Saab Seaeye Ltd v Atlas Elektronik GmbH & Anor

This is a patent action about underwater mine clearance operations. The claimant (Saab) is the manufacturer of, inter alia, defence equipment. The defendants are the owners of two patents relating to mine clearance devices. The claimant seeks revocation of the patents on the grounds of want of novelty, lack of inventive step and (in relation to one of them) insufficiency. The defendants counterclaim for infringement. There are third parties to the action, but two of them have settled and the third (Mr Dann) has undertaken to be bound by the result of the claim and did not participate at the trial. There are non-patent claims in these proceedings, but they have been stayed for the time being or, as against Saab, have been discontinued. At the beginning of the trial there was an application by the defendants to amend their counterclaim in relation to “essential means” infringement. Saab did not oppose the amendment, and I formally allow it. The trial comes on with a degree of expedition ordered by this court because of Saab’s commercial need to answer the questions which this action raises.

The priority dates of the patents were about a month apart (August and September 2010), and the experts agreed there was no material difference between those dates for the purposes of any of the issues in this action. I can therefore proceed on the footing that they shared the same priority date for practical purposes.

Most of the background to the patents was common ground and it is convenient to set it out here. Underwater mines are explosive devices intended to explode in the proximity of ships so as to sink or damage those ships. They are of various types. Some are physically attached to ships. They can be ignored for the purposes of this action. Some are tethered or moored - these are of the kind commonly depicted in cartoons as floating below the service and looking like roundish objects with spikes on them, though they do not, in the real world, all look like that. Others are deployed so as to rest on the sea bed. They can all be activated in various ways - by contact, by sound, and by detecting magnetic variations caused as a steel ship passes nearby.

During or at the end of conflicts it becomes necessary to clear mines that have been laid. The process of doing so (mine counter-measures, or MCM) falls into two categories - mine-sweeping and mine-hunting. The former activity involves indiscriminate activity such as towing cutting devices under the surface across a wide area, to release such moored mines as may be there so that they float to the surface where they can be destroyed by gunfire. Dragging chains along the sea bed is one indiscriminate way of dealing with bottom-dwelling mines. Acoustically or magnetically triggered mines can be sought to be exploded by mimicking (“spoofing”) the acoustic or magnetic signature of a ship to which the mine is tuned to respond (“influence mine sweeping”). This involves using large scale equipment to generate a spoof signal over a wide area in the hope that relevant mines are nearby, listening and sensitive to the signal. The patents are not concerned with any of this sort of indiscriminate activity.

Mine hunting is a more targeted activity and is what the patents in this case are concerned with. The purpose of this activity is to identify specific mines, and then to attack those mines individually. If an individual moored mine is identified its specific cable could be cut so that it floats up to the surface where it can, as above, be destroyed by gunfire. However, the preferred method is to destroy the mine without releasing it to float around in an uncontrolled fashion, and in any event seabed mines have to be destroyed where they are.

One method of destroying them is to use a fairly large amount of explosive deposited nearby, and to explode it, in the hope (or expectation) that that explosion will also trigger the mine. This procedure has drawbacks. It requires the use of a substantial amount of explosives and a degree of uncertainty as to whether it will be enough to do the job. There are obvious dangers in ships moving round the sea containing large amounts of explosives. A more focused activity requires divers to swim up to the mine and physically disable it. The dangers of this are obvious.

A yet more focused activity is to explode a smaller amount of explosive in a shaped charge close to or even fixed to the mine itself. Such devices can be placed closed to the mine, or even attached to it by a diver. Alternatively, they could be manoeuvred close to the device by using a remotely operated vehicle (“ROV”). An ROV is what its name suggests - a vehicle capable of manoeuvring under water and carrying out various tasks there - transportation, carriage of objects, and the manipulation of objects. Many have a form of manipulator arm on them. They are controlled by an operator at some distance via a wire carrying an electronic signal (generally speaking - it is possible to do it via an acoustic signal, but that does not have as much bandwidth for the signal). The ROV will generally carry lights and cameras so that the operator can see what he or she is doing on a remote screen. By the priority date there were expendable ROVs, to which explosives were fitted in the form of a shaped charge. A shaped charge is a way of focusing the explosive effect so that less explosive is necessary than would otherwise be the case. Those ROVs were manoeuvred close to the mine, and detonated via an electrical signal (over an umbilical connecting cord) or an acoustic signal when close enough, with the shaped charge doing its work of destroying the mine. The ROV is sacrificed. That is obviously expensive.

The explosive device has preferably to be physically fixed to the mine. The ways of doing that are limited. One particularly striking, and counter-intuitive, way of achieving it featured in one of the patents and in the prior art. It was apparently found that a nail gun could be used without setting off the mine. One of the patents involves this technique. In this action it is disputed as to whether it was common general knowledge at the priority date.

In this action Saab was represented by Mr Thomas Moody-Stuart; the defendants were represented by Mr Iain Purvis QC and Mr Tom Alkin.

UK Patent no 2482576B was published on 8th February 2012, and has a priority date of 6th August 2010. It is entitled “A neutrally buoyant underwater weapon clearance appliance”. The claims said to be independently valid are set out in Annex 1 to this judgment. The defendant has applied unconditionally to amend this patent and does not seek to defend the unamended patent. I can therefore consider the proposed amended patent only. Having considered the observations of the Patent Office, I consider that it would be right to allow the amendment, provided that the amended claims would be valid. I therefore have to consider those would-be amended claims only.

The Annex sets out the alleged independently valid claims as sought to be amended. Claims 1 and 9 are said to be infringed; the others are not.

In order to assist navigation round the claims, the significant matters in relation to each claim are as follows. Generally speaking, the invention involves carrying an explosive to a mine on an ROV. Claim 1 describes a device for clearing mines, which has a “detachable connection” to an ROV, has neutral buoyancy and a nail-gun for attaching the clearance appliance (explosive) to the body of a mine. Claim 2 describes such a device but adds that it has no “alignment moment”, that is to say that it does not pitch, turn or roll in the water (it is in no way self-righting). Claim 5 substitutes a spoofing device to the triggering mechanism to set off the mine. Instead of a charge which blows itself and the mine up, the device contains a spoofing device which mimics the signal to which the mine is sensitive, thus triggering it. Claim 9 adds simultaneity of the firing of the nail gun to attach the device with the process of detachment of the device from the delivery vehicle - as the nail fires, the clearance device is detached from the means of transportation (as opposed to the nail gun firing first, and then the detachment happening afterwards). Claim 10 is a claim to a particular method of achieving that simultaneous disconnection.

Turning to the body of the patent, the description describes a technically simple method of disposal by sending divers to fit an explosive charge manually; but that is dangerous to the diver and limited to maximum diving depths. A further method is to send an unmanned underwater vehicle (ROV), using a manipulator arm fitted to the vehicle, to place a large charge “in the area” of the mine and exploding it; but that requires a large amount of explosive which makes trimming the ROV difficult, requires large storage facilities on the mine-hunting ship and gives rise to a dangerous presence of large quantities of explosive on that ship. A yet further method involves mine-destruction “drones” with shaped charges. These underwater unmanned vehicles are moved “directly adjacent” to the target mine and the shaped charge is detonated, together with the vehicle. This method is costly because the vehicle is sacrificed.

The description says that the invention addresses the problem of making disposal cheaper without significantly increasing the amount of explosive charge required. This requires the exact positioning of the small amount of explosive. It is also necessary to address the problem of trimming. The release of an explosive device which had hitherto been attached to a small ROV would be capable of affecting the trim of the latter, leading to the need to re-trim (and extend the time of operations) or the loss of the ROV.

“The invention therefore provides for the weapon clearance appliance not to be an integral component of an underwater vehicle but to provide it only as an attachment for an unmanned underwater vehicle. The underwater vehicle is therefore now used only as a transport vehicle for the actual weapon clearance appliance, which is released from the underwater vehicle. For this purpose, the weapon clearance appliance has means for detachable connection to the underwater vehicle. The weapon clearance appliance is therefore separated from the underwater vehicle in the area of the weapon, thus allowing the underwater vehicle to move away from the danger area before the weapon is detonated.” (Pages 3-4).

I have quoted those words, and emphasised some of them, because they are relevant to a construction point that arises in this action.

The device is constructed so as to have neutral buoyancy, so that its release does not lead to a change in the buoyancy affecting the underwater vehicle.

The method is said to provide for explosives, and/or for a spoof device capable of simulating the characteristics of marine vessels. The spoof device is attached to an ROV, and attached to or placed down adjacent to the mine. It mimics a passing vessel and triggers the mine to explode itself.

In one special embodiment the device is chosen so that it has no specific alignment in the water, so that it not only remains in the position it was left in (because of its neutral buoyancy), it also remains in the alignment it was left in. This is said to prevent any torque from acting on the ROV when the device is released.

Shaped charges and spoof devices are included in later special embodiments. The charge or spoof device can be activated by radio buoy, an electro-acoustic transducer, a firing cable or a time fuse.

A further special embodiment requires a “holding apparatus” for fixing the device to the mine. This can be a “nail-firing appliance”, an electromagnet, a reduced-pressure appliance and/or a clamping device. Such apparatuses are advantageously activated by the device making contact with the mine; additionally, this can be achieved by metal sensors which signal that the device is directly in the area of the mine.

“According to a further special embodiment of the weapon clearance appliance, the means for detachable connection of the weapon clearance appliance to an unmanned underwater vehicle and the holding apparatus are designed such that, when the holding apparatus for fixing the weapon clearance appliance to the weapon is activated, the means for detachable connection are operated at the same time, thus releasing a mechanical connection between the weapon clearance appliance and the unmanned underwater vehicle. [page 8 - this is the simultaneous detachment of claim 9].”

There then follows a special embodiment in which a particular form of attachment/detachment mechanism is identified in words and in drawings. It is one in which the detachment mechanism is on the device itself, and in which the firing of the nail gun works so as move other parts which effect the detachment. This embodiment is elaborated further later and ultimately found expression in claim 10.

The description goes on:

“According to a further specified example the means for detachable connection are designed to hold the weapon clearance appliance on a supporting frame of the unmanned underwater vehicle. According to this example, the weapon clearance appliance is placed in the area of the weapon by the unmanned underwater vehicle. An embodiment such as this is advantageous when it is not possible to attach the weapon clearance appliance directly to the weapon, for example because of severe shellfish growth. In a situation such as this, the weapon clearance appliance is placed on the base of the waterway or the seabed in the area of the weapon, and the clearance charge is then fired or the spoof device activated.”

The description goes on to describe one particular embodiment, described by reference to diagrams, in which the clearance device is held on to the nose of an ROV by means of a rubber band. The band is attached by loops to two retractable features on the device and acts on a projection on the ROV. Thus the device is connected to the ROV. When the release mechanism is operated the retractable features retract, releasing the rubber band and the device is then separated from the ROV. That level of generality of description will suffice. For present purposes it is sufficient to note that it is an embodiment in which the detachable connection mechanism operates by features operating on the device itself (the two retractable features), and not features on the ROV. “In the process, the connection between the weapon clearance appliance and the underwater vehicle is broken …”.

Page 18 says:

“The invention makes it possible to provide conventional unmanned underwater vehicles, in particular minehunting drones, with a multiple use, since the actual weapon clearance appliance is provided merely as an attachment to the underwater vehicle. Therefore, only the weapon clearance appliance need be sacrificed during each operation, while the unmanned underwater vehicle can be reused.”

This UK patent (number 2483861B) is entitled “Attachment device and assemblies and systems using same”, was published on 28th March 2012 and has a priority date of 21st September 2010. It relates to “an impact initiated attachment device and assemblies and systems using the same … The device is particularly useful in the attachment of a disrupting explosive charge to ordnance for disposal”, principally but not exclusively in a marine environment.

The description refers to the desirability of placing a shaped charge at an optimum stand-off distance when disposing of underwater mines, and goes on: “It is the positioning and fixing of the shaped charge which has been a capability gap in some fields.” The patent seeks to address this by proposing a front face of the device with a protruding trigger. The device is presented to the mine and when pressed against it the trigger operates a mechanism which deploys an attachment device - a nail gun, hooks or harpoon devices. In the words of the description:

“In one aspect there is provided in the following an impact initiated attachment device for attachment to an target [sic], the device comprising: a housing having a front face which abuts against the target in use, one or more fasteners, a drive mechanism for driving the fastener(s) from a first position within the housing to a second position protruding from the front face of the housing, and a trigger mechanism for triggering activation of the drive mechanism comprising a trigger extending from the front face of the housing.

“Because the trigger extends from the front face of the housing, all that is required to activate the drive mechanism is to press the device onto the surface of the target whereby to press the trigger. It is therefore very simple to operate since the user does not have to place the device and then fire it, which might be particularly difficult in an underwater environment. The user can concentrate on the positioning of the device and simply has to apply some additional pressure to activate the drive mechanism.

…

A line such as a bungee or other elastic cord may be attached to the housing arranged to be released from the housing on activation of the drive mechanism. This is particularly useful when carrying the device underwater. The line may be used to attach the device to a vehicle for example so that the vehicle is released when the attachment device has been activated.

…

The assembly may comprise a cowl or collar to which the attachment device and one or more disruptors are attached. This is particularly suitable for use with a submersible vehicle. The cowl or collar may be designed to fit over the nose of the vehicle so that the assembly can be guided by the vehicle. The assembly may comprise multiple disruptors arranged in parallel around the collar or cowl.”

Issues of construction arise in relation to the mechanical nature, or otherwise, of the trigger mechanism, and issues arise in relation to the manner in which the explosive charge device is attached to a delivery ROV with a “line” attached to the device. The parts of the description relevant to those matters are as follows. I omit numerical cross-references to diagrams.

Page 5 describes hand-held deployment (deployment by a diver) and page 6 goes on to consider “ROV deployment”.

“Alternatively, a shore or ship mounted dispenser for the proprietary plastic tube initiation system may be used and one or more impact initiated attachment devices (Grapplers) and Disruptors may be mounted in a Cowl or collar mounted on an ROV (or manned vehicle).

A typical operation using this set up would be to prepare an assembly comprising two Grapplers and two Disruptors mounted into a Cowl. This would then be fitted to a ROV or Sea Scooter using a Bungee Cord attachment which in turn is joined via Release Bolts on the Grapplers to be described in more detail below.”

The Grappler (the fixing mechanism) is described on page 7.

“The Grappler consists of a Barrel assembly, comprising a housing which may be produced from aluminium alloy and a Breech assembly, which may be produced from acetyl or other similar material. Both components and are preferably designed such that they are sealed to prevent water ingress and operate from 0 to 300 metres depth or more. Upon impact with a target, the front mounted trigger is activated and the Grappler is attached to the target by means of one or more high-tensile nails, which are fired (and retained) using a proprietary powder actuated impact tool cartridge. The illustrated cartridge is a rim activated cartridge.

More specifically the Grappler is an indirect acting tool that uses a retained piston and captive nail to transfer energy from a proprietary impact tool cartridge to secure the grappler unit to the desired target. Contained in the Barrel Assembly is the Trigger mechanism, which ultimately fires the Grappler. The trigger is designed such that it is sealed to prevent water ingress into the housing. The trigger itself is a simple protrusion extending through a hole in the front wall of the housing. The trigger is retained in the housing by means of an annular collar which is biased against the front wall by means of a spring captured in a chamber within the housing. The trigger may be direct acting as shown Fig 2b or may act by other means. Trigger has a shaft that extends through the chamber and is integral with the shaft in this example. The collar is sealed against the ingress of water into the chamber.

An alternative trigger mechanism is shown in Fig 2c.”

A description of 2c appears, but it is unnecessary to set it out. It is sufficient to record that it describes a different mechanical link between the trigger and the ultimate detonating mechanism.

The Cowl is described in more detail at page 11.

“The cowl consists of a moulding of reinforced glass fibre or similar material with holders for the Grapplers (usually two but at least one), manacle restraints for the Disruptors and other clips and restraints to attach the proprietary plastic tube detonator initiation system.

…

The Cowl is slid onto the front of the ROV and a bespoke Bungee Cord is clipped on underneath joining both Release Bolts on the Grapplers.”

And at the foot of page 12 is a passage relied on by the defendants:

“The assemblies of attachment and disruptor enable a disruptor/demolition method that is less susceptible to stray electromagnetic and electrostatic energy than current methods.”

The relevant claims appear in Annex 2 below. Claims 1 and 3 are said to be independently valid and infringed. Claims 7 and 15 are said to be independently valid but not infringed.

Three witnesses provided evidence by way of witness statement and documents only, without being called for cross-examination. Two of them were Mr Keith Riches and Mr Lewis Simpson. Their material provided information about one of the pieces of prior art which was a physical product known as SeaSting. SeaSting was (as will appear) a project developed by BAeSEMA for disposing of mines, being deployed by an ROV, fastening itself with a nail gun and then exploding a shaped charge. Both men were involved in its development. Their evidence goes to its functionality and, to a degree, the scope of its disclosure and marketing. Since they were not cross-examined their evidence stands unchallenged.

The third was Mr Christopher Lade, who gave evidence proving and elaborating on a product and process description of the Saab device which is said to infringe in this case (called Ballista). No issue arises as to his evidence.

Mr David Jackson gave expert evidence for Saab. He has a degree in mechanical engineering and has 25 years of experience in underwater weapons systems and worked for many years for GEC Marconi (which became part of BAe Systems) until he left and became a consultant in 2011. There is no doubting his experience in underwater defence systems, and his knowledge of mine counter-measures. He worked on a mine-hunting product (called Archerfish) involving an expendable ROV and which was supplied to the US Navy. As it happens he was the project manager for the SeaSting project late in its life and took the decision to abandon it. He was briefed on its capabilities but had no part in its development. He was not able to give detailed evidence about certain aspects of its functionality. He approached his expert evidence carefully but his views on obviousness were sometimes a little over-enthusiastic, as is best demonstrated by his reliance on a piece of prior art called Backstein (US patent no 4,970,957). This piece of prior art was effectively abandoned when Mr Moody-Stuart stopped cross-examining Dr Takel (the defendants’ expert) on it, and actually abandoned in his final speech. I shall not take time setting out its content. Suffice it to say that reliance on it always looked somewhat far-fetched, and Mr Jackson’s evidence about it somewhat stretched notions of obviousness and requires one to view the rest of his evidence on obviousness accordingly.

Dr Stephen Takel gave expert evidence for the defendant. He is a physicist and mechanical and electronic engineer by training and has worked in the defence sphere for some time. Between 1994 and 2001 he worked in or with mine counter-measures, and has kept abreast of matters since. Like Mr Jackson, he is technically well qualified to give expert evidence in this case. He gave his evidence in a clear and measured manner. However, he did demonstrate a tendency to view something as inventive just because it had not occurred to him personally, which does not suggest that he always had an eye on the skilled team as he ought to have done. I have to view with a little care any views he expressed on inventiveness but on the whole preferred his evidence to Mr Jackson’s where they differed. His reasoning tended to be more appealing.

There was little between the parties in relation to the skilled addressee to whom the patents should be taken to be addressed, and such differences as there are do not seem to matter much.

Mr Jackson considered that the skilled addressee would be a team with a practical interest in designing, developing and testing an underwater mine counter-measure system, comprising an ROV used to inspect, target and destroy mines and sunken ordnance. The team would be an engineer having a working knowledge of explosives and warheads, an engineer having a working knowledge of ROVs and a person with practical experience of such a system - for example, an ex-Navy officer or a qualified diver experienced in explosives and mine clearance.

Dr Takel considered the addressee would be a single person who was a designer of MCM and specifically Explosive Ordnance Disposal (EOD). He or she would be a physicist or mechanical or electrical engineer working in the MCM department or laboratory of a defence research or manufacturing company or organisation, with an undergraduate degree in physics or engineering but probably no post-graduate academic qualifications. He or she would have worked there for at least 5 years.

The expertise of each side’s addressee was essentially the same save that Mr Jackson added the person with practical experience and Dr Takel did not think that that person would necessarily be part of an addressee team. If it matters I think that Mr Jackson is more likely to be right, but I did not detect that that made any difference to this case.

One aspect that was of potential importance to common general knowledge was the length of experience of the individuals in the notional team. Dr Takel’s report accepted that his person would have at least 5 years post-qualification experience, and in his cross-examination he accepted that Mr Jackson’s team would be likely to have experience of 10 years or more. If it matters, I am not satisfied that one has to imagine that length of experience - between 5 to 10 years is probably appropriate. The age profile is of potential relevance because on the facts it might impact on whether SeaSting was common general knowledge. As will appear, it would be more likely to have been noticed by someone with 10 years experience at the priority date than by one with 5.

The general material set out in the Introduction section of this judgment contains a large part of common general knowledge (CGK). There was some debate as to whether SeaSting, and in particular the use of nailguns demonstrated by SeaSting, was CGK. By the end of the trial it was not clear that this made a difference to either side’s case, but Mr Moody-Stuart relied on it and did not abandon the contention and I should deal with it. It was the only contentious issue in relation to CGK.

SeaSting was the commercial implementation (or attempted commercial exploitation - it was never sold) of one of the other pieces of prior art, namely BAe (see below). In short, it was a device delivered up to a mine by an ROV with an arm. The device contained a shaped charge and fixed itself to the mine automatically when sensors pressed against the mine indicated there was contact. The fixing was done by a nail gun. The release of the device from the ROV arm was done by the operator of the ROV.

SeaSting was designed by BAe in the early 1990s. The concept was first devised by a Mr Derek Beattie, and Mr Keith Simpson took it over in 1995. It received a certain amount of publicity in the trade, though the extent was not clearly demonstrated, and it was presented to a number of navies (apparently at face to face meetings). It was demonstrated at sea to the Swedish navy, but it was never sold and the project was abandoned in 2000.

Publication of it occurred in the following manner:

Based on this material Mr Moody-Stuart invited me to find that SeaSting and nail gun attachment was CGK. I find that it was not, as at the priority date. While Jane’s was a standard work of reference to which the skilled addressee might be expected to refer, and whose contents could amount to CGK on well-known authorities, SeaSting did not appear in the edition of Jane’s current at the priority date, and there was no evidence that the skilled addressee would go back over a number of years. In any event, even if the addressee did go back 4 years, it would still not disclose the nail gun attachment, and more work would be necessary to track down particulars. Brochures would not give all those particulars. It was not demonstrated how easy it would have been to track down the two conference papers which disclose them. Jane’s does not provide or generate a route to CGK of SeaSting for these purposes.

It was also submitted that the UDT conference would have been attended by a skilled addressee, who would therefore have encountered the two presentations and the particulars of SeaSting there. This would work for Mr Moody-Stuart if the skilled team had a person of sufficient age and experience to have attended it. As at the priority date this would have had to have been a person of at least 14 years experience. It would then have had to have been of sufficient interest to that person that it would have been remembered, across the years, by that person, and form part of their stock of knowledge. It was submitted that the use of a nail gun was striking and would have stuck in the mind. That may be true to a degree, but there was no evidence that it was so striking that it was somehow passed on or disseminated to newcomers to the field in any significant way. Taking this evidence in the round I am not satisfied that SeaSting, or the nail gun aspect of it, was CGK in 2010.

There was no dispute as to the correct approach to construction. Both sides cited the same authority. In Virgin Atlantic v Premium Aircraft [2010] RPC 8 at [5] the Court of Appeal summarised the general principles follows:

“One might have thought there was nothing more to say on this topic after Kirin-Amgen Inc v Hoechst Marion Roussel Ltd [2005] RPC 9. The judge accurately set out the position, save that he used the old language of Art.69 EPC rather than that of the EPC 2000, a Convention now in force. The new language omits ‘the terms of’ from Art.69. No one suggested the amendment changes the meaning. We set out what the judge said, but using the language of the EPC 2000:

“[182] The task for the court is to determine what the person skilled in the art would have understood the patentee to have been using the language of the claim to mean. The principles were summarised by Jacob LJ in Mayne Pharma Pty Ltd v Pharmacia Italia SpA [2005] EWCA Civ 137 and refined by Pumfrey J in Halliburton Energy Services Inc v Smith International (North Sea) Ltd [2005] EWHC 1623 (Pat) following their general approval by the House of Lords in Kirin-Amgen Inc v Hoechst Marion Roussel Ltd [2005] RPC 9. An abbreviated version of them is as follows:

(i)

The first overarching principle is that contained in Article 69 of the European Patent Convention.”

(ii)

Article 69 says that the extent of protection is determined by the claims. It goes on to say that the description and drawings shall be used to interpret the claims. In short the claims are to be construed in context.

(iii)

It follows that the claims are to be construed purposively – the inventor’s purpose being ascertained from the description and drawings.

(iv)

It further follows that the claims must not be construed as if they stood alone – the drawings and description only being used to resolve any ambiguity. Purpose is vital to the construction of claims.

(v)

When ascertaining the inventor’s purpose, it must be remembered that he may have several purposes depending on the level of generality of his invention. Typically, for instance, an inventor may have one, generally more than one, specific embodiment as well as a generalised concept. But there is no presumption that the patentee necessarily intended the widest possible meaning consistent with his purpose be given to the words that he used: purpose and meaning are different.

(vi)

Thus purpose is not the be-all and end-all. One is still at the end of the day concerned with the meaning of the language used. Hence the other extreme of the Protocol – a mere guideline – is also ruled out by Article 69 itself. It is the terms of the claims which delineate the patentee’s territory.

(vii)

It follows that if the patentee has included what is obviously a deliberate limitation in his claims, it must have a meaning. One cannot disregard obviously intentional elements.

(viii)

It also follows that where a patentee has used a word or phrase which, acontextually, might have a particular meaning (narrow or wide) it does not necessarily have that meaning in context.

(ix)

It further follows that there is no general ‘doctrine of equivalents.’

(x)

On the other hand purposive construction can lead to the conclusion that a technically trivial or minor difference between an element of a claim and the corresponding element of the alleged infringement nonetheless falls within the meaning of the element when read purposively. This is not because there is a doctrine of equivalents: it is because that is the fair way to read the claim in context.

(xi)

Finally purposive construction leads one to eschew the kind of meticulous verbal analysis which lawyers are too often tempted by their training to indulge.”

Both sides also draw attention to the need not to confuse carefulness with over-meticulousness - per Pumfrey J in Haliburton v Smith [2006] RPC 2 at para 69.

An issue arises as to the meaning of “means for detachable connection” in claim 1 (and claim 9). The defendants say that that wording requires some sort of active element on the clearance device which does the connecting and disconnecting, and not just something passive like a loop or an eye which engages with something on the ROV. There must be something active on the device itself which participates in the connection and disconnection, even if there is also something active on the ROV. The claimant says that such a limitation is not required by the patent. Something passive like a loop or eye is within the claims.

As a matter of ordinary English, and taking the wording of claim 1 by itself for the moment, they would not, in my view, require the defendants’ limitation. A “means for connection” can be active or passive. The word “detachable” describes the connection - it describes a connection that can be purposely broken. A combination of the words does not require the breaking means to be present on any particular side of the connection provided that the connection can be broken. The defendants’ construction would mean that the words could be paraphrased: “means for detaching (or breaking) a detachable connection”. As words in the context of claim 1 they do not naturally bear that meaning.

However, it is necessary to construe them in the context of the description. There are a few parts of the description that bear on the point.

The first is an absence. There is nothing in the description which suggests why putting the means for disconnection on the device (as opposed to the ROV or an arm on the ROV) has any particular merit. As Mr Moody-Stuart put it, the limitation does not fulfil any purpose of claim 1, and its purpose does not otherwise appear from the description.

Pages 3 and 4 introduce the concept. Having set out the disadvantages of other methods of disposal (divers, non-proximate explosive charges, expendable drones which are manoeuvred close to the mine), and referred to the costliness of the last of those alternatives, it then sets out the desirability of using small charges, a small ROV and the problems for self-trimming of ROVs posed by carrying charges. It then goes on (as set out above):

“The invention therefore provides for the weapon clearance appliance not to be an integral component of an underwater vehicle but to provide it only as an attachment for an unmanned underwater vehicle. The underwater vehicle is therefore now used only as a transport vehicle for the actual weapon clearance appliance, which is released from the underwater vehicle. For this purpose, the weapon clearance application has means for detachable connection to the underwater vehicle. The weapon clearance appliance is therefore separated from the underwater vehicle in the area of the weapon, thus allowing the underwater vehicle to move away from the danger area before the weapon is detonated.” (my emphasis)

This is the first reference to “means for detachable connection”, and the emphasis is on the ability to disconnect. The detachable connection is “For this purpose”, and the “purpose” is for the ROV to be only a means of transportation, as opposed to being part of the explosive device. That purpose is achieved by an ability to detach, wherever the active means of disconnection are. This supports Saab’s construction.

The same point arises out of the last paragraph of the description which seems to summarise the purpose of the invention:

“The invention makes it possible to provide conventional unmanned underwater vehicles, in particular minehunting drones, with a multiple use, since the actual weapon clearance appliance is provided merely as an attachment to an underwater vehicle. Therefore, only the weapon clearance appliance need to be sacrificed during each operation while the unmanned underwater vehicle can be reused. This makes it possible to significantly reduce the costs of mine clearance.”

While this does not directly address the construction point, it does indicate a purpose of the invention to which the presence or absence of active connection/disconnection means on the device is irrelevant, and it does not indicate what purpose, in terms of the invention, would be served by having active means on the device.

Mr Purvis relied on a later passage which deals with simultaneity of disconnection at page 9:

“According to a further special embodiment of the weapons clearance application, the means for detachable connection of the weapons clearance appliance to an unmanned underwater vehicle and the holding apparatus are designed such that, when the holding apparatus for fixing the weapon clearance appliance to the weapon is activated, the means for detachable connection are operated at the same time, thus releasing a mechanical connection between the weapon clearance appliance and the unmanned underwater vehicle.”

He submitted that this presupposes that the “means” (which are on the device, not the ROV) can be operated - that is to say, they are active. This is a linguistic proposition. I agree that this is what this embodiment is describing. In this embodiment the means are designed to be “operable”. However, this is a specific embodiment, and in my view it is only a limited detraction, for the purposes of the specific embodiment, from the general position, which is that the means are not required to be active. It is also true that the patent contains drawings showing a simultaneous release mechanism, but the drawings are described (on page 9) as special embodiments, and the elaborations of those drawings are similarly described. They are not stated as reflecting some general limitation (in this respect).

Mr Purvis also relied on “a further example, outside the scope of the claims” (in the words of the amended patent) under which the “means for detachable connection” were designed to hold the weapons clearance application on a frame of the unmanned underwater vehicle. The frame is placed in the area of the mine. He pointed out that in this case the connection means must be active on the device, and not on the frame, and that supported his general construction. I agree, but again that is a special embodiment (and not one within the claims anyway).

Last, he pointed to claim 9, which (as pointed out above) seems more clearly to require an active connection on the device. Even if it did (which I consider below) it is a special embodiment which does not, in my view, coincide with the scope of the general limitation applicable to claim 1.

Taking all these factors into account, I consider that the expression “means for detachable connection” in claim 1 does not require that those means have an active element on the weapons clearance device. Some passive means suffice.

One further point arises because of one of the pieces of prior art (BAe). It arises because that device has 4 flat surfaces intended to be gripped by a “hand” on an ROV manipulator arm. For the reasons that I give later, I do not consider that a mere gripping area amounts to any “means of detachable connection”.

Claim 9 has to be considered separately because, as appears above from the passage from page 9 of the description, as a matter of language it appears that the means for detachable connection referred to there is actually active on the device - the means on the device are “operated”, which suggests that they have to be active. The operation “releases” the connection. In this case I accept the submissions of defendants - the “means for detachable connection” have to have an active element on the device which is capable of being operated and releasing the connection. The same applies to claim 10.

A point arises over the meaning of the words “a trigger mechanism for triggering activation of the drive mechanism comprising a trigger extending from the front face of the housing” in claim 1. The defendants contend that these words are limited to a mechanical trigger mechanism. The claimant contends that they cover any type of sensor and activation system - electronic, hydraulic, mechanical or anything else.

I agree with the defendants’ case on this, largely for the reasons that they give. The Oxford Dictionary of English contains definitions which support this case. “Trigger” is defined as:

“a small device that releases a spring or catch and so sets off a mechanism, especially in order to fire a gun”;

And “mechanism” as:

“a system of parts working together in a machine; a piece of machinery”.

Thus the conventional use of the phrase supports the conclusion that a mechanical, and not (for example) an electrical mechanism is required. This gains further support from within claim 1 itself in the reference to the trigger “extending from the front face of the housing”, which clearly suggests a mechanical part at at least that stage of the chain of action.

Nothing in the description in the patent points in any other direction. At page 7 it describes a plainly mechanical trigger. It goes on to describe an alternative system, again obviously purely mechanical.

On p 12 the description sets out one of the apparent benefits of the invention:

“The assemblies of attachment and disruptor enable a disruptor/demolition method that is less susceptible to stray electromagnetic and electrostatic energy than current methods.”

Mr Purvis submitted that this advantage was true only if the system was mechanical. An electrical system would risk the additional influences which the mechanical system was said to be designed to avoid. This point has to be approached with caution. As Mr Moody-Stuart pointed out, this advantage is apparently related to the assemblies, not the mechanical trigger. It might be capable of being true if related expressly to the mechanical nature of the trigger system, but it is not expressly so related. Furthermore, the “current methods” are not identified in the description, so it is not possible to elaborate the meaning from that factor. The experts were not in terms asked about this possible advantage and to what it would relate, and did not volunteer possibilities in their reports, although in other parts of their evidence they did refer to undesirable influences from some electrical components. Accordingly, while this statement would be consistent with possible benefits of a mechanical (as opposed to an electrical) system, I do not think it has the weight which Mr Purvis would give to it.

Nonetheless, I consider that Mr Purvis’s construction is correct.

A similar debate arose in relation to claim 3, and the answer is the same.

Three pieces of prior art were cited against the patents in suit in the pleading. They were SeaSting, a UK patent GB2234203A (”BAe”) and a paper by Mr Beattie. These are all closely related - SeaSting seems to be the commercial exploitation of BAe, and Mr Beattie’s paper describes various features of it. However, by the time of the trial Mr Moody-Stuart indicated that he was not relying on Beattie, so I shall consider only the other two pieces.

This patent (priority date 3rd July 1986) claims to be for:

“An underwater weapon 1 for mine countermeasures a shaped charge 2 which is attached to a target mine 26 by means of an explosive attachment unit 10 e.g. a nail gun. Contact sensors 5 and hydrostatic transducer 7 in conjunction with safety and arming unit 6 make the weapon safe until it is underwater in contact with a mine. A transducer 9 enables the weapon to be armed and detonated by remote control. A multi-faceted portion 8 enables the weapon to be gripped and manipulated by remote control.”

The figures in the patent are these:

The description goes on to describe the attachment of an explosive device so as to secure it to an object which it is wished to destroy, the attachment preferably being via a nail gun. It extols the virtues of a shaped charge and refers to various aspects which it is not necessary to set out here. Figures 2a to 2d show the weapon being transported, attached and armed by a remote signal. Various features of the device are described and at page 2 it is said:

"A faceted portion 8 at the closed end of the weapon casing enables the entire weapon to be gripped and manipulated by the remotely operated vehicle…"

Page 3 goes on:

“In figure 2a the underwater weapon is carried to the target area by the remotely operated vehicle 20 which carries the weapon using the claw 23 of the manipulator arm 22 to gripped facets 8 on the weapon. Control signals are transmitted between the remotely operated vehicle and the disposal weapon via a command line 25 connected to a socket 16 on the mine disposal weapon. When the remotely operated vehicle has reached its target area the mine to be disposed of is inspected with on-board sensors.… In figure 2b the manipulator arm 22, with weapon is extended and the ROV is moved towards mine 26 until contact is made with the mine casing and signalled by sensors 5. Although an articulated manipulator arm 22 is shown being extended and folded in figures 2a to 2d a limited function manipulator arm could be used which is fixed and has no extension capability. When the operator receives a signal indicating that successful contact has been made with the mine the operator triggers the explosive fastening device 10 by a signal via the ROV command line 25 (Figure 2b). Alternatively the fastening device can be arranged to detonate automatically upon contact of the sensors 5 with the mine casing. Upon receipt of the correct signal the firing mechanism 11 detonates a percussion 12. The force of the explosion from the percussion cap drives the toughened nail 13 forwardly through aperture 14 to penetrate the casing of the mine to be destroyed. As the nail 13 penetrates the mine casing a friction weld is produced which holds the weapon securely in place on the mine. When the weapon is attached to the mine the ROV is withdrawn and recovered (Figure 2c). The weapon is armed and detonated remotely by an acoustic signal 27 which is detected by acoustic receiver 9 (Figure 2d).”

Seasting is described in general terms above. The evidence as to what SeaSting disclosed lacked precision. There were marketing brochures, but they did not describe all its features. Some things have to be inferred from less than clear photographs. Mr Riches and Mr Simpson give some evidence about it, but Mr Riches does it by producing brochures and then completing a claims chart in relation to the integers of various claims. Mr Simpson does that as well, but he does also provide some shortly stated general descriptions of its functions. It was, as appears above, deployed by an ROV and had two sensors above which would abut a target mine. This would cause attachment via a nail gun (the nail protruding between the two contact sensors, according to Mr Simpson), and it was neutrally buoyant (a feature not disclosed by BAe). Having been connected to the mine, the ROV would disconnect from SeaSting and retire to a safe distance. The charge (a shaped charge) would then be detonated remotely using acoustic methods. Both witnesses say that “The detachable connection used was a manipulator arm” and that it was tested with a particular ROV (a Double Eagle). This is apparently shown in a picture in a brochure. The arm is shown as looking like a rod, connected somehow to the SeaSting, but the manner of connection is not apparent. The brochure comments that “SeaSting is deployed using a limited function manipulator arm on a Remotely Operated Vehicle (ROV)”.

The manner of attachment of the arm to SeaSting is not known. There was a degree of intelligent speculation by the experts. Dr Takel originally suggested that the connection might be magnetic, but indicated considerable uncertainty about that in cross-examination. He thought that the end of the manipulator arm might have been inserted into an orifice on SeaSting, but resisted the idea that something like a pole would be a manipulator arm. Mr Jackson did not express any particular view - he treated SeaSting in this respect as being like BAe even though it did not obviously have the equivalent of the facetted gripping feature of BAe. All in all it is not possible to understand how SeaSting worked in this respect with any clarity.

As the case developed it became apparent that SeaSting added very little to BAe. Mr Moody-Stuart did not quite abandon it as a separate piece of prior art, but it can (save where the contrary appears) usually be taken as the same, and I generally do not consider it separately, doing so only where necessary.

The challenges to the 576 patent were novelty, obviousness and insufficiency.

There was originally an assertion that BAe anticipated the 576 patent. However, Mr Moody-Stuart abandoned this attack in his final submissions because he accepted that BAe did not disclose neutral buoyancy.

However, Saab continued to assert that SeaSting anticipated this patent. Seasting does disclose neutral buoyancy. Whether it anticipates will depend on whether it has “means for detachable connection”. In order to understand this it would be necessary to understand how Seasting was actually attached. That never was established. If it was in effect gripped, as contemplated by BAe, then even on the construction that I have found that would not, in my view, amount to “means for detachable connection”. Gripping by, or providing a gripping surface for, is in my view not the same as providing means for a connection. One of the experts speculated that there may have been an orifice which somehow received part of the manipulator arm. That might provide passive means for detachable connection, but one needs to know what the system was before forming a view. If Saab wish to rely on a piece of prior art as anticipating it must make sufficiently clear what the prior art discloses. It has not done so on the evidence, so it is not possible to establish anticipation. The manner of joining (I prefer not to use the word “connection” at this point) has not been made apparent by Saab. I find that the 576 patent was not anticipated by SeaSting.

There was little dispute on the relevant law applicable to this attack on the patents, and one side or the other (or sometimes both) invited me to rely on the following principles, which are variously applicable to the obviousness attacks on both patents.

Most of the principles can be extracted from the judgments of Kitchin and Lewison LJJ in Medimmune v Novartis [2012] EWCA Civ 1234.

“84.

The starting point is that an invention must involve an inventive step, and it is to be taken to involve an inventive step if it is not obvious to a person skilled in the art having regard to matter which properly forms part of the state of the art at the priority date (sections 1(1) and 3 of the Patents Act 1977, corresponding to Articles 52(1) and 56 of the European Patent Convention).

85.

It is often convenient, but by no means essential, to consider an allegation of obviousness using the structured approach explained by this court in Pozzoli v BDMO SA [2007] EWCA Civ 588, [2007] FSR 37 at [23]:

“(1)(a) Identify the notional 'person skilled in the art';

(b)

Identify the relevant common general knowledge of that person;

(2)

Identify the inventive concept of the claim in question or if that cannot readily be done, construe it;

(3)

Identify what, if any, differences exist between the matter cited as forming part of the 'state of the art' and the inventive concept of the claim or the claim as construed;

(4)

Viewed without any knowledge of the alleged invention as claimed, do those differences constitute steps which would have been obvious to the person skilled in the art or do they require any degree of invention?”

….

93.

Ultimately the court has to evaluate all the relevant circumstances in order to answer a single and relatively simple question of fact: was it obvious to the skilled but unimaginative addressee to make a product or carry out a process falling within the claim….”

(per Kitchin LJ)

“181 …It cannot be said too often that the statutory question is: was the invention obvious at the priority date? It is not: was it obvious to try? The questions of the degree of expectation of success and the length of time thought to be needed to undertake a trial have taken on lives of their own. I think that this happened in our case. Insistence on the statutory question is not a novel thought. It is also an obvious one: see Conor Medsystems Inc v Angiotech Pharmaceuticals Inc [2007] EWCA Civ 5 [2007] RPC 20 (§§ 44, 45 per Jacob LJ, approved on appeal: [2008] UKHL 49 [2008] RPC 28 § 42 per Lord Hoffmann; § 49 per Lord Walker; § 55 per Lord Neuberger). In Generics (UK) Ltd v H Lundbeck A/S [2007] EWHC 1040 (Pat) [2007] RPC 32 (§72) Kitchin LJ (as he then wasn't) said:

“The question of obviousness must be considered on the facts of each case. The court must consider the weight to be attached to any particular factor in the light of all the relevant circumstances. These may include such matters as the motive to find a solution to the problem the patent addresses, the number and extent of the possible avenues of research, the effort involved in pursuing them and the expectation of success.”

… 184. In many “obvious to try” cases, it is the idea of trying that constitutes the inventive step. It was no doubt this that led Sir Donald Nicholls V-C to say in Molnlycke AB v Procter & Gamble Ltd [1994] RPC 49 that:

“… obviousness connotes something which would at once occur to a person skilled in the art who was desirous of accomplishing the end." (Emphasis added)”

One must guard against an obviousness case built on taking a number of successive steps to get to the invention, because of the danger of using impermissible hindsight. As Fletcher-Moulton LJ said in British Westinghouse v Braulik [1910] RPC 209 at 230:

“I confess that I view with suspicion arguments to the effect that a new combination, bringing with it new and important consequences in the shape of practical machines, is not an invention, because, when it has once been established, it is easy to show how it might be arrived at by starting from something known and taking a series of apparently easy steps. This ex post facto analysis of invention is unfair to the inventors and in my opinion is not countenanced by English Patent Law.”

And as Lord Diplock said in Technograph v Mills & Rockley [1972] RPC 346 at 362:

“The cross-examination of the respondent’s expert followed with customary skill the familiar ‘step by step’ course. I do not find it persuasive. Once an invention has been made it is generally possible to postulate a combination of steps by which the inventor might have arrived at the invention that he claims in his specification if he started from something that was already known. But it is only because the invention has been made and had proved successful that it is possible to postulate from what starting point and by what particular combination of steps the inventor could have arrived at his invention. It may be that taken in isolation none of the steps which it is now possible to postulate, if taken in isolation, appears to call for any inventive ingenuity. It is improbable that this reconstruction a posteriori represents the mental process by which the inventor in fact arrived at his invention, but even if it were, inventive ingenuity lay in perceiving that the final result which it was the object of the inventor to achieve was attainable from the particular starting point and in his selection of the particular combination of steps which would lead to that result.”

Contemporaneous events (relied on by Mr Purvis) have their place in the assessment of obviousness, but such evidence is secondary to the expert evidence and it must be viewed with care:

“71.

The primary evidence to be considered is that of properly qualified expert witnesses who can explain to the court whether the relevant step would have been obvious to the skilled person having regard to the state of the art. All other evidence is secondary to that primary evidence. Evidence of contemporaneous events can be of assistance when testing the expert's primary evidence. So also can evidence of commercial success. Secondary evidence has its place and the weight to be attached to it will vary from case to case. However, such evidence must be kept firmly in its place as Sir Donald Nicholls V.C. explained in Molnlycke v Procter & Gamble Ltd (No 5) [1994] RPC 49 at 113.” (per Kitchin LJ).

Mr Moody-Stuart also drew attention to the next paragraph:

“72.

If a particular route is an obvious one to take, it is not rendered any less obvious from a technical point of view merely because there are a number, and perhaps a large number, of other obvious routes as well: Brugger v Medic-Aid Ltd [1996] RPC 635 at 661.”

In Schlumberger Holdings v Electromagnetic Geoservices AS [2010] RPC 33 Jacob LJ considered secondary evidence at some length. He observed:

“77.

It generally only comes into play when one is considering the question "if it was obvious, why was it not done before?" That question itself can have many answers showing it was nothing to do with the invention, for instance that the prior art said to make the invention obvious was only published shortly before the date of the patent, or that the practical implementation of the patent required other technical developments. But once all other reasons have been discounted and the problem is shown to have been long-standing and solved by the invention, secondary evidence can and often does, play an important role. If a useful development was, in hindsight, seemingly obvious for years and the apparently straightforward technical step from the prior art simply was not taken, then there is likely to have been an invention.”

And at paragraph 88 he warned against treating secondary evidence as of only minor importance.

In Brugger Laddie J considered the position where all that is in issue is design choices:

“Choosing between a number of equally effective readily available design options does not involve an inventive step …”.

Though, of course, that is only applicable where all that is in issue can be properly characterised as “design choices”. One must not allow that concept to mask an inquiry as to whether various choices were obvious or inventive.

From time to time Mr Purvis relied on that fact that a given feature had apparently not occurred to Mr Riches or Mr Simpson when SeaSting was in the course of development. He was able to do that because they had each given evidence about Seasting, and he suggested that their silence on the point demonstrated the lack of obviousness of the feature.

I did not find this a significant part of the evidence in this case. Mr Riches was the Business Development manager of various projects. It does not seem that he had an involvement with the actual development of the ideas behind SeaSting and was more concerned with its promotion, though he understood its manner of operation. Accordingly, his silence on any particular point is not particularly significant.

Mr Simpson was more concerned with the actual development of the product, so his state of mind would be more relevant. His evidence does not deal with what other ideas he might have had in his evidence, and the points in question are undeveloped in his evidence. True it is that he does not say that any given alternative development did or did not occur to him or the development team, but I do not draw any real significance from his failure to say anything about features which SeaSting or BAe did not have in the circumstances of this case and bearing in mind the nature of the evidence that he gave.

Accordingly, secondary evidence does not play a real part in this case. I should also record that in his final submissions Mr Moody-Stuart told me that Mr Simpson was “extremely ill” and was not capable of providing more evidence than he had provided. I have not taken that into account. There was no evidence of that, and I am not aware that his evidence was given under a Civil Evidence Act notice which indicated that he could not attend to give evidence. He was not cross-examined because Mr Purvis chose not to have him called.

Neutral buoyancy is not disclosed by BAe, but Dr Takel accepted that it would be obvious to add that feature to BAe. It is accepted that neutral buoyancy is disclosed by SeaSting. The obviousness debate in relation to BAe took place on the only remaining distinctive battleground, namely of “means for detachable connection”.

My conclusion on whether (in claim 1) the detachable means have to be active means that the actual battleground at the trial becomes irrelevant. The dispute about obviousness and connection was one in which Mr Moody Stuart was saying that it would be obvious to add active means to BAe and Mr Purvis was saying it was not. In the light of my conclusion that (for the purposes of claim 1) active means are not required, that debate focuses on the wrong point. However, I have formed a view about what BAe discloses which means that another area of dispute arises. On the proper construction of the patent it is apparent to me that the device has to have some means of connection, and I have reached the conclusion that BAe does not disclose any. It merely has 4 flats which are gripped. The word “detachable”, in my view, connotes an “attachment”, and in its context I consider that it requires more than merely gripping. There must be some degree of interlinking. Having a place where the device can be conveniently gripped by something which does no more than grip does not, in my view, amount to “means of detachable connection”. Whether or not a mere grip is an “attachment” (the opposite of “detachment”, and which has to exist before there can be a “detachment”), using that as an isolated expression, and whether or not a grip, by itself, is a “connection”, the composite phrase, to my eyes, requires an attachment in the form of a degree of fixing or interlinking which is not provided by a mere grip. So a site which provides surfaces for gripping is not “a means of detachable connection”. I should say that this was not a point specifically taken by Mr Purvis, but one or two of his submissions or questions in cross-examination suggested the point might arise.

That conclusion, together with my conclusions on whether active means are required by the patent, means that the battleground ought to shift. It means that a question might arise as to whether it would be obvious to add a passive means of detachable connection. That was not a point that was addressed as such at the trial. However, the point having occurred to me in the course of the preparation of this judgment, I asked the parties for their submissions on it, and duly received them. Having considered the matter carefully, I consider that I can fairly deal with the point, the parties having had a further opportunity to consider that question when provided with the draft of this judgment.

I find that it would have been obvious to add such means. Having considered the evidence on the type of ROVs available on the priority date, and the limited evidence (particularly of Mr Takel in cross-examination) and applying a degree of common sense, I think that it would be obvious to apply some means of attachable connection (in the sense of forming an attachment) which can be detached from something at the end of an ROV arm. It is not a great step from holding the device with a “hand”, and certainly not an inventive one.

However, the battleground at this trial does arise in relation to claim 9 and it is convenient to deal with it at this point

Mr Jackson considered that this would be an obvious development over BAe (and SeaSting). He considered that the skilled team would have considered alternative connections involving simple modifications to the ROV and/or the clearance device, and each would have been standard and routine design choices. Among those obvious choices would have been putting some form of active release mechanism on the device itself.

I think that this was an instance of “design choice” being used to mask something more profound that would be required. BAe clearly shows a device being manipulated into place with a gripper arm by which it is held. There are particular flats on the device which permit this grip. The ROV operator decides whether the conditions are right to release the grip, and opens the claws of the gripper accordingly. Mr Jackson’s reasoning involved keeping the arm. It was, he said, a good way of keeping the ROV, and its electromechanical influences, away from the mine lest it trigger it. The arm might be a full manipulator arm or a limited manipulator arm. A limited arm might not have a claw. In such a case a release system would have to be devised and one such system might be a latch on the device which would be triggered by a line extended from the ROV. What he did not explain was why one would consider moving the active attachment mechanism away from the ROV at all. The ROV is the thing that is controlled by the operator, and the operator will also control the release. It would be natural (obvious) to replace a claw mechanism with some other mechanism for attaching where the claw would otherwise be but it was not apparent why it would be obvious to move this mechanism to the device. That seems to me to be a step too far, and is an example of using the concept of design choice to mask something more original than that.

Dr Takel did not think an active detachment mechanism on the device was obvious. He was cross-examined on this and stood fast. He was asked to consider the use of an ROV without a manipulator arm, and if necessary attaching something like a pole or a frame to carry the device to the mine. He was then invited to consider that the ROV was a limited class of ROV which did not have a power socket so the release mechanism would have to be mechanical, and was invited to accept that it would be obvious, in that case, to put the active means of release on the device. He did not accept that, and I accept his evidence about it. I do not see the mechanical non-inventive logic that would put the release mechanism there rather than on the frame or pole. The suggestions made to him, and the case of obviousness made on the basis of them, also have the vice of inviting a chain of supposition which takes the situation too far away from BAe. BAe shows an ROV with a fully functioning manipulator arm, though it also refers to a limited function arm. Mr Moody-Stuart’s chain of reasoning first requires a step away from that to ROVs without that function. It also (in his frame analysis) steps away from it in requiring the ROV to get closer to the mine (thereby offending his own expert’s perception that it was a good thing to keep the mine at manipulator arm’s length); and then he adds the suggested serious modification of the holding/releasing mechanism. That is too many steps.

I therefore find:

For the same reasons it is not obvious over SeaSting either. SeaSting involves a manipulator arm, possibly limited, but there would for similar reasons be no obviousness in adding the active means to the device.

The additional integer in relation to this claim is one which provides that the device has no alignment moment - it is not “self-righting” in water and will stay in the same orientation (unless acted on by a force). This is said by the patent to have the effect that the ROV would not have to re-trim itself on releasing the device - otherwise the self-righting effect would have to be compensated for by trimming the ROV while it was carrying it, and that trimming would have to be adjusted when the device is released. This aspect is not explicitly referred to in the 576 patent, though as Mr Jackson accepted the effect of the nail gun as shown in the diagrams would provide a “keel effect”.

Mr Jackson’s evidence was that designing the relative positions of the centres of buoyancy and mass so as to achieve a desired result was a routine design choice in designing underwater vehicles and devices. Appropriate design of those relative positions would determine whether the device had an alignment moment or not. It would have been obvious to design the device so as to minimise the power expended by the ROV, to allow for a speedier operation and to minimise the effect on trim of releasing the device. In his cross-examination he repeated that considering this sort of factor was a frequent design consideration, though most of his evidence was given in relation to the design of ROVs rather than the devices they carry. He gave a particular example of an ROV used in this field (as a self-destructive device) called Archerfish (on which he had worked) which was designed so as to minimise roll and pitch stability because it was desired to produce a manoeuvrable machine.

Dr Takel accepted that the extent to which one wished to make an underwater appliance self-righting was a standard design consideration. Again, much of his evidence was in relation to ROVs themselves, but he accepted the need to consider alignment moments for devices other than ROVs. Given a need to use a device with all sorts of ROVs (which was put to him, as was the fact that that might be dangerous to do so) he accepted that one way to avoid trimming issues was to have a device with no alignment moment. One thing that was particularly put to him was use with a small ROV of a kind which had hitherto been treated as disposable, though he later expressed the view that that use would be inventive. He had never seen anything used from an ROV which did not have an alignment moment to keep it stable.

In my view the starting point for this consideration is the fact that alignment moment is something that is considered as a matter of routine in the design of underwater appliances. There was no evidence to the effect that there was an inbuilt assumption that one always had to have some specific stability. The 576 patent itself did not say anything express about it. If it was being considered, then in my view, on the evidence, the absence of alignment moment would be considered as much as a positive alignment moment, even if the answer was often that it was not desired or needed. It is within the range of possible answers for the uninventive skilled team which considers implementing the 576 patent. I find that this feature was obvious over BAe (and SeaSting).

It follows that Claim 2 is obvious over BAe (and Seasting).

The obviousness point here arises over the use of a spoof device rather than a shaped charge. Saab submits that it would be obvious to modify BAe (and SeaSting) to bring about this substitution.

Mr Jackson’s report said that the use of spoofing had been known for decades. It was used in influence (wide area) mine-sweeping and in mine jamming. It was a technique with which the skilled team would have been deeply familiar and he asserted it would have been obvious to consider using a spoofing device in place of the shaped charge. His cross-examination on this was short. He had not seen (but had not looked for) evidence that the idea had been used elsewhere. He acknowledged that the idea did not occur to him when developing Archerfish but explained that spoofing was less reliable than explosives and the brief for Archerfish required the reliability which explosives brought in achieving “high order detonation” of the mine (ie actually triggering the explosive in the mine). This was an obvious development.

Dr Takel’s report rebutted this assertion of obviousness with a similar generalised statement that it was not obvious. In cross-examination he said that, other than wide-scale influence sweeping, he had never heard of a spoof device fixed to a mine to make it go off. He identified one of the benefits as being able to attach spoofing devices to a number of mines, and then detonate them all at once to clear a path for an approaching force. He did not see any difficulty about making a spoofing device small enough.

I prefer Dr Takel’s evidence on this point. The focus of mine hunting in the 576 patent, and the prior art referred to in it, was on using explosives to cause an explosion. The use of a spoofing device is rather different. Dr Takel thought it was clever when he saw the idea, and although his views about obviousness are not as important as the reasons for them, I think that that reflects a lack of obviousness.

I therefore find that this integer is not obvious over BAe and Seasting.

This claim has two integers to consider for obviousness - first, active means for detachment on the device and second, disconnection from the ROV simultaneously with the attachment of the device to the mine. I have already held that the first is not obvious. I therefore deal here only with the second.

There is nothing in BAe which teaches anything like simultaneous detachment. The device is in the grip of the manipulator arm and presumably requires positive release by the operator. I accept Mr Purvis’s submission that if anything it teaches away from automatic detachment because the operator would want to make sure that attachment had taken place.

Mr Jackson’s report suggested that the skilled team would be motivated to consider simultaneous detachment in order to keep the mission time down. I found that unconvincing. It would involve the saving of only seconds in a mission lasting as much as 10 to 15 minutes (or more). While I would accept that a skilled addressee would have in mind the speed of a mission, I do not consider that the saving of a few seconds while an operator checked whether there had been a fix would be motivation to bring about simultaneous attachment, particularly since the supposition of BAe is probably that the operator will want to check before releasing - that was the way SeaSting worked, according to Mr Riches.

After his report Mr Jackson said that it occurred to him that another reason for simultaneous detachment was to reduce the effect of buffeting on a vehicle that was attached too long to a mine. Such buffeting from currents and vortices was a known phenomenon as at the priority date, and could damage the device or ROV. This idea had not occurred to him by the time he wrote a reply report (he did not refer to it there).

Dr Takel disputed obviousness and pointed out that the evidence of Mr Riches indicated that in SeaSting the operator visually checked to ensure that fixing had taken place before releasing SeaSting and withdrawing the ROV. In cross-examination he accepted Mr Jackson’s two reasons would be reasons for not wishing to delay around fixing the mine (though Mr Moody-Stuart’s own question described the time reduction as “marginal”), and accepted that a third (which had not occurred to Mr Jackson) was that one would not want to keep an ROV in too close proximity to a mine for longer than necessary because of the electromagnetic influence it might have on it. He accepted that they would be reasons to “drop and run”. He did not accept, however, and it was not put to him, that those factors would have been sufficiently apparent to the skilled addressee to make simultaneous detachment an obvious addition to BAe.

I do not consider that the idea was obvious. Mr Jackson’s reasoning demonstrated clear hindsight thinking. His second factor was something that occurred to him once he had thought about the idea of simultaneous detachment for some time, which is not an effective approach to the question of obviousness. It does not support a case that the skilled team would have had them in mind and would have sought the simultaneity answer to them. His first reason (shortening mission time) would not, in my view, provide an incentive at all. As Mr Moody-Stuart said, the time effect was “marginal”.

I therefore consider that this integer is not an obvious development of BAe.

This claim is for a particular manner of effecting a simultaneous detachment. Since the idea behind it is not obvious (see claim 9) this cannot be obvious either.

There were several aspects to the originally pleaded claim of insufficiency, but by the time of final speeches the point came to be one turning on the requirement of “neutral buoyancy”.

The nature of this point, too, changed during the course of the proceedings. Mr Jackson’s report expressed the view that it is in practice impossible to achieve perfect neutral buoyancy across a range of water densities, and variable densities might occur in closely proximate areas of water. One could design for the purpose for which the device was to be deployed, but it was unclear to him what the parameters of “neutrally buoyant” were.

This seemed to be the basis on which Mr Moody-Stuart opened the case. He described the point as being “how neutral is neutrally buoyant”. This point (or these points) were not pursued in final speeches. Mr Moody-Stuart took another tack at that point, relying on an ambiguity version of insufficiency and evidence that emerged from Dr Takel’s evidence. He seemed to accept precision in neutral buoyancy was not required - it was not a precise concept for these purposes and a limited variation about the absolute would suffice and was within the claims and that “substantial” neutral buoyancy would suffice. (I infer this from his not taking issue with a reference in Dr Takel’s evidence to this effect). However, he took up a reference to neutral buoyancy in the patent referring to its purpose:

“Release [of the appliance] does not lead to a (positive or negative) change in the buoyancy of the underwater vehicle. The underwater vehicle can therefore be controlled without any problems even after [release]”.

And he then relied on evidence given by Dr Takel in cross-examination in which he is said to have opined that in this context neutral buoyancy would depend on the vehicle to which the device was attached. The bigger the ROV, the less the significance of a departure from strict neutral buoyancy. Mr Moody-Stuart’s case was that unless one knew the characteristics of the ROV to which the device was to be attached, one could not tell whether the patent would be infringed. The patent was ambiguous and therefore insufficient.

The statutory requirement of “sufficiency” is expressed in section 72(1)(c) of the Patent Act 1977. As Arnold J said in Sandvik v Kennametal [2011] EWHC 3311 (Pat) at para 106:

“106.

A patent is invalid "if the specification does not disclose the invention clearly enough and completely enough for it to be performed by a person skilled in the art" (section 72(1)(c) of the 1977 Act). The patent will be insufficient if the skilled person is unable to carry out the claimed invention given the description of it in the specification and common general knowledge (sometimes called "classical insufficiency").”

The question of insufficiency by reason of ambiguity was dealt with by Lord Hoffmann in Kirin-Amgen Inc v Hoechst Marion Roussel Ltd [2005] RPC 9. The problem in that part of that case was that the relevant claim required a comparison with a comparator (uEPO) which varied from sample to sample. At paragraph 126 he said:

“The Court of Appeal… said that it was sufficient that some uEPO could be tested against eEPO by SDS–PAGE. The fact that it did not specify which uEPO and that choosing one uEPO would bring the product within the claim and another would not was ‘lack of clarity dressed up to look like insufficiency.’ For my part, I do not think that can be right. If the claim says that you must use an acid, and there is nothing in the specification or context to tell you which acid, and the invention will work with some acids but not with others but finding out which ones work will need extensive experiments, then that in my opinion is not merely lack of clarity; it is insufficiency. The lack of clarity does not merely create a fuzzy boundary between that which will work and that which will not. It makes it impossible to work the invention at all until one has found out what ingredient is needed.”

I do not consider that the present case falls within the same category. There was no doubt about what “neutral buoyancy” meant, in its narrowest sense. If it matters, I consider that Mr Moody-Stuart was correct to accept, as he apparently did, that neutral buoyancy was not an absolute and that a limited variation around the absolute would still provide “neutral buoyancy”. Minor departures from the absolute would not materially affect the object of this integer. So there was no difficulty about its meaning in that wider sense either. This would no more be a question of ambiguity-insufficiency which invalidated the patent than the departure from verticality would have been in Catnic Components Ltd v Hill [1982] RPC 183 (where the question was actually one of construction).

The question is then whether the possible variation in the ROV is of the same nature as the variability of comparator in Kirin-Amgen in terms of sufficiency. I do not consider that it is. In Kirin-Amgen the invention was defined, in terms, by reference to a comparison which was variable from sample to sample. That is not the same in the present case. The concept of neutral buoyancy is not so used, and is a standalone concept which would have been understood by the skilled team. They would have understood that some variation around the absolute would still come within the concept. The concept is capable of being affected, in practice, by variables. One of them is the density of the water in which the device is to be used. However, as Mr Jackson accepted in his report, that was a known feature and:

“… the skilled team would have had no issue in designing the buoyancy of an appliance for the purpose for which it is going to be deployed. The difficulty I have with this claim is that it is unclear to me what the parameters of “neutrally buoyant” are.” (para 176)

So that variable poses no difficulty for the skilled team, who can design around it. The first sentence also applies to the nature of the ROV. So far as necessary, the skilled team would be likely to be able to design for variations of ROV. There was no suggestion that these were so variable as to pose any problem in this respect, and the skilled team would be able to carry out the invention despite this variable.

All this is nothing to do with the ambiguity version of insufficiency relied on by Mr Moody-Stuart, and this insufficiency point fails. I also record misgivings as to the manner in which it arose. Mr Jackson’s report suggested that his only difficulty with the patent in terms of insufficiency was the degree of permitted variation around the absolute - see his paragraph 176 quoted above. Mr Moody-Stuart’s written opening submissions made it clear that this was the only point, and (as identified above) his oral opening submissions confirmed that. The variable nature of ROVs was something that came up in cross-examination as a sort of concept, and was dealt with briefly, with no consideration of the scope of likely variations which would seem to me to have had a potential bearing on the point. It was not really fully developed as a matter of evidence. This was unsatisfactory, and had the position on the merits not been so clear I would have been unlikely to have allowed reliance on the point.

These are obviousness points, as appears below.

I have already determined that this patent refers to a mechanical system only (see the construction point above). The principal debate in relation to obviousness under this claim relates to BAe and whether it would be obvious to implement it with a mechanical as opposed to an electrical system. Saab contended that it would.

The first logical question is whether BAe discloses an electrical system. It does not explicitly specify the nature of its operating system in terms. Dr Takel considered that various references in it had the effect that the skilled addressee would assume an electrical connection. Mr Jackson did not accept that.

In my view Dr Takel is correct. As he points out, BAe contains various references to “signals”. A safety and arming unit “is responsive to signals from a hydrostatic sensor and a pair of contact detection sensors”; the device is manoeuvred by the arm “until contact is made with the mine casing and signalled by [the contact] sensors”; “when the operator receives a signal indicating that successful contact has been made …”; “upon receipt of the correct signal the firing mechanism detonates a percussion cap”. I consider that he is correct in saying that they betoken an electrical system. Mr Jackson suggested that some of the signals might be mechanical, like an old-fashioned railway signal (his parallel). I think that is extremely unlikely. It is hard to see how that would work, and his interpretation involves a forced view of “signal”.

That being the case, the obviousness point becomes one of whether it would be obvious to implement BAe with a mechanical rather than that electrical system. Mr Jackson maintained it was. However, such a system would face some complexities in relation to BAe. First, it would have to cater for 2 sensors. Second, BAe provides for a signal both to operate a safety and arming unit (to make sure the device did not go off prematurely or in handling) and (in the relevant embodiment) the mechanism which fired the nail gun. That would extend the functions of the rods, levers, springs and other matters that had to achieve all this. Mr Jackson stated that it was possible, though he had not even roughed out how it might be achieved. All this was in the face of his acceptance that in any event there were some items which had to be electrically powered anyway - the sensors and the safety and arming unit. He expressed concern about increasing electromagnetic influences by having an electronic triggering mechanism, but had not calculated whether it would be significant. In the end he accepted that it might not be possible to achieve the sort of mechanical system he had in mind. This does not lead to a compelling case for obviousness.

Dr Takel was cross-examined first on the footing that BAe did not clearly disclose an electrical mechanism; then he was asked to assume delivery by a diver, which would require the minimising of influences. He accepted that starting from BAe, in those circumstances, one would consider a mechanical system, but he did not accept one would implement it and still tended to favour electrical mechanisms. When asked to consider the context of delivery by ROVs, he declined to accept that choosing a mechanical system would be non-inventive. The trouble with this cross-examination was that it proceeded from two false positions. The first is delivery by a diver. BAe does not suggest that. If anything, it teaches away from it and towards delivery by an ROV. The second is that it ignores the fact that BAe teaches sensors connecting with the safety and arming unit as well as the nail driver, and the obviousness of doing that via mechanical means was not put. All in all I do not consider that this cross-examination advanced Mr Moody-Stuart’s case.

My conclusion is that Mr Moody-Stuart has failed to establish the obviousness of providing a mechanical system in BAe, and so his case on this point fails.

There was a second small obviousness point about the re-positioning of the trigger from where it was shown in BAe to the front of the “housing” as in the 861 patent. Dr Takel seemed to accept that this was obvious, and I so find. Mr Purvis did not address any submissions to the point.

No additional point arises in relation to SeaSting.

This claim involves the addition of a “striker” to the drive mechanism. Mr Moody-Stuart advanced the same obviousness case on electrical vs mechanical as in relation to claim 1. It fails for the same reason as the obviousness point on claim 1.

This claim is for an attachment device (a) which is attached by a “line” (b) which is released on activation of the mechanism which fixes to the mine. This is said to be obvious over BAe (and Seasting).

Integer (b) is simultaneous detachment. I have already held this to be not obvious above.

Integer (a) relates to a particular means of attachment - a “line”. An example is given of a bungee which is attached to the housing so that it is released when a release bolt (which is part of the triggering mechanism) is propelled to its forward position. Considering this in the context of BAe therefore involves substituting the apparent claw on the end of the manipulator arm, or similar feature, with a line or cord.

Mr Jackson said that tying one thing to another underwater was a familiar fixing technique. I am sure it is, in appropriate circumstances. In his cross-examination he accepted that a manipulator arm of some sort was a given of BAe, but that different methods of fixing to it would be considered, and one of them would be a line. He did not say it would be obvious to use a line. He did not offer a suggestion as to how this line would be simultaneously released from a manipulator arm, or how it would be deployed. I am afraid I found his evidence in cross-examination on this point, which was intended to support the obviousness of this sort of combination of line and manipulator arm, completely unconvincing. At one point he suggested adapting the control line that is shown in the BAe diagrams (which passes signals from the device to the ROV) to be a line which holds the device in place. That seemed to me to be a very odd suggestion.

Nothing in Dr Takel’s cross-examination would support the idea that this sort of development of BAe was obvious. He was asked some questions about attachment and bungees, but did not accept that their use was obvious in this context. He was criticised by Mr Moody-Stuart for substituting what would and would not have occurred to him personally for questions of inventiveness, and he did indeed seem to do that, but in this context that approach does not affect the rest of his evidence.

For those reasons I find that this claim is not obvious over BAe (or Seasting).

This claim involves the attachment of fixing and explosive devices to a collar or cowl. The “assembly” referred to is an assembly of one or more explosive devices and one or more fixing devices as described in previous claims.

This claim has an unstated assumption behind it. The cowl is, according to the description, a cowl for fitting over the nose of an ROV or a sea scooter (a powered underwater towing device). The purpose of the collar is not described but it would seem that it would be another way of attaching it to such a device. Accordingly, the extent of the inventiveness of this claim has to be judged in this context. The main dispute between the experts boils down to whether this underlying assumption involves inventiveness. Mr Jackson said that to do this would be an obvious development of BAe; Dr Takel did not.

Mr Jackson approached the matter on the footing that the development of ROVs had moved on since BAe. By the priority date there were smaller, cylindrical drones which would be in the contemplation of the skilled team as a potential delivery system. Such devices did not have manipulator arms so a different method of delivery would have to be used for these drones (which were smaller, lighter and cheaper). They would have to be fixed somehow away from the very front of the drone because the drones had devices such as cameras there, and a structure such as a collar or cowl would be an appropriate way of holding the device away from those devices. If the devices were on a collar, a hydrodynamic covering would be obvious to apply to it. He said that each step along this route away from BAe would be the sort of thing the skilled team would do, along with separating the attaching (nail gun) module from the explosive device so that each would be separate on the collar.

Dr Takel suggested that none of these steps were suggested by BAe and disputed the obviousness of taking them. He identified the real inventiveness in using an ROV without a manipulator arm - the sort of smaller ROV contemplated by Mr Jackson. If a small vehicle of that nature was the starting point then he accepted that a collar was not inventive but a cowl was. He said he had seen collars attached to cylindrical objects but not cowls.

As identified by Mr Purvis, this attack really turns on whether or not the skilled team, when faced with BAe, would think (non-inventively) about delivery by a smaller ROV, cylindrical in shape, and without a manipulator arm. If they would then they would think about attaching devices by a collar (though probably not by a cowl). In my view they would not consider the alternative ROVs. It is true that such ROVs existed at the priority date, and would have been known to the skilled addressee. They were of different types, larger and smaller, some cylindrical, some far from cylindrical. Those cylindrical ones did not have a manipulator arm. Some of the cylindrical ones were non-disposable versions of the disposable mine-hunting type. However, having considered Mr Jackson’s evidence on the point, I do not consider that it would have non-inventively occurred to the skilled addressee, considering the development of BAe, to use an armless ROV to deliver the explosive device to the mine. BAe demonstrated an apparently feasible method of getting a mine to a device. The mine was held by familiar technology - a manipulator arm. The smaller armless ROVs were either vehicles which had built in explosives, or were versions of them which were intended not to get explosive to a mine and then withdraw - they had different functions. The idea of using one of those ROVs actually to carry explosives to the mine would, in my view, have been inventive.

Mr Purvis said that this conclusion was supported by Mr Jackson’s own evidence. When first instructed he had been given BAe without the patent and asked to consider what improvements and changes could be made to the system described there. It did not appear that this particular improvement had occurred to him at that point. When this was pointed out to him by Mr Purvis, by way of challenge, he replied:

“Because I was not asked to contemplate carrying BAe on a small ROV. I was asked to consider BAe, the patent.”

This provides a small, but only a small, piece of support for Mr Purvis’s case (which is what I have just found in favour of). It demonstrates that it did not occur to him to look at a smaller ROV as an improvement on BAe, and he can be regarded as an inherently more inventive person than the skilled team. But on the facts of a case like this the significance of that is limited. I would have reached the same conclusion without this piece of evidence.

Accordingly that key element of the claimant’s reasoning is absent. Without it the obviousness case stops at an early stage in Mr Jackson’s slightly extended chain of reasoning. It follows that this claim is not obvious over BAe. The same applies to Seasting.

The infringement issues that arise do so in relation to one of Saab’s products called Ballista. Saab does not intend to deal in this product any more, but issues may arise in relation to historic acts. It is not disputed that Ballista infringes claims 1 and 3 of the 861 patent. Limited issues arise in relation to the 576 patent in relation to “means for detachable connection”. It does not appear to be disputed that insofar as Saab is correct on the “means for detachable connection” point, then Ballista infringes. I have held that it is correct in relation to claim 1 but not claim 9. There is, therefore, an issue in relation to claim 9.

Ballista was the subject of a product and process description and I had the benefit of having a sample which demonstrated its working in terms of the connection between its two parts (without explosives or the armed mechanics of a working nail gun). The relevant parts of its working can be shortly described as follows, by reference to the photographs and drawings in Annex 3.

The complete product is shown in Photo 1. The lower fatter part is the part containing the shaped charge and can be ignored. The upper thinner part contains the connection/disconnection part, which is relevant for present purposes. The nail gun unit is to the right; the ROV would attach to the left. The target mine would be situated to the right.

Photo 2 shows the end of the nail gun unit which presses against the mine in its state after the nail gun has fired. The protruding button is the trigger button which triggers the firing of the nail gun inside. The emerged nail is shown alongside the trigger button.

Photo 3 shows both ends. The protruding element to the left is a cocking piece, which I shall call the silver rod. This piece is an active piece in that it moves as part of the detaching process. It is cocked, and then released when the nail gun fires. In a released state it is completely within the unit. In its cocked state it protrudes; the photograph shows it in its cocked state, achieved by inserting a special tool and pulling it out until it clicks into place. It is linked internally so that as part of the firing process it disappears rapidly into the housing.

Diagram 1 shows a representation of the whole device in its cocked and assembled state, waiting to be fired against a mine which would be to the left. Again, the lower bulk is the shaped charge and can be ignored other than noting it is attached to Parts 1 and 2. The upper part is the nail gun and detachment mechanism. It comprises three parts, shown labelled 1, 2 and 3. Part 1 is the nail gun part, corresponding to photos 2 and 3 (with a slightly more bulbous end). It is held in part 2, which has flanges and a recess at its right-hand end (marked). (This part is to the left of Photo 1). That assembled unit fits into part 3, which is the part which is attached to an ROV and retained on the ROV when release has been effected (the “retained part”).

The retained part has a central rod which is pressed against by a spring and is linked to two jaws (shown). The drawing shows the spring in a compressed state. When in that state the jaws move inwards. In an uncompressed state the central rod moves to the left and the jaws move outwards. If the assembled nail gun device is inserted and the central rod is depressed (and the spring compressed) the jaws move inwards and engage with the flange and recess in part 2, holding the parts together. If the spring were not compressed, the central rod would move left and the jaws would move outwards, releasing their grip.

The release mechanism exploits that arrangement. In its cocked state the silver rod protrudes from the right hand end of the nail gun unit. It engages with the central rod of the retained part, pushing it and compressing the spring. The jaws then close and engage with the flanges, holding the parts together. The nail gun part is constructed so that when the nail fires the silver rod retreats to the left (inside the unit). That releases the constraint on the central rod and its spring, and it moves left. That in turn causes the jaws to part and nail gun elements (parts 1 and 2) are released.

The defendants say that that silver rod which is cocked and which retreats is an active means which initiates the release mechanism, it is on the device part of the arrangement and there are therefore means for detachable connection within the meaning of those words in claim 9. Saab disputes this on the footing that the active means for disconnection are on the ROV side (the retained part). The silver rod is at most the means for activating the means for detachable connection.

The answer to this question, in my view, involves considering the actual wording of claim 9, and not deciding it by reference to the paraphrase “active means”, which has otherwise done good service in these proceedings. Claim 9 uses the words “means for detachable connection are operated”. One needs to identify the means and any “operation” that might take place. In my view it would not be right to view the means, in this case, as being only the flanges. The means for detachable connection also involve the silver rod, without which there would (on Ballista) be no connection or disconnection. Until the silver rod engages with the central rod there is no connection, and until it retreats there is no disconnection. So both elements are part of the means of the detachable connection means. Those means are “operated” when the silver rod retreats, with the consequential mechanical effects on the retained part. In the circumstances Ballista, in my view, infringes claim 9.

It follows that Claims 1 and 2 of the 576 patent fall to be revoked. The remainder of the revocation claims fail. The infringement claims succeed to the extent appearing above. I shall hear the parties further as to what relief flows from my findings on infringement.