Judge Hacon :
- The Claimant ("VPG") owns European Patent (UK) No. 2,099,626 B1 ("the Patent") which claims an invention entitled "System for indicating the state of loading of a vehicle". In particular those who operate trucks and other commercial vehicles need to know that the vehicle is neither over-loaded such as to make the vehicle in breach of relevant regulations and possibly dangerous on the road, nor under-loaded such that the vehicle is being used inefficiently. The invention claimed is an improved means of measuring the load of a vehicle and displaying it.
- The Defendant ("AEL") admits infringement of the Patent if it were valid, but alleges that Patent is invalid. The sole ground of invalidity relied on is lack of inventive step in relation to each of three items of prior art. This fell to be assessed as of 29 November 2006.
- The only claims alleged to be independently valid are claims 1 and 7, 13, 14 and 15. The Defendant's allegation of invalidity was directed only to claims 1 and 7. Claim 1 is a product claim and claim 7 a method claim which closely corresponds to claim 1. Neither party identified any reason why the validity of the two claims would not stand or fall together, so I will focus just on claim 1.
- Mr Hughes appeared for the Claimant and Mr St Ville for the Defendant.
- The Patent is directed to a type of on-board system for indicating the state of loading of a vehicle. 'On-board' systems use a device mounted on the vehicle, as opposed to external means of assessing the loading such as a weighbridge. The device in the Patent is incorporated in what are called 'suspension assemblies', each of which consists of a number of 'suspension components'. Paragraph 3 of the Patent explains the basic structure of a vehicle for the purposes of the invention:
" A commercial vehicle is typically made up of three major components for description purposes, namely multi-component suspension assemblies, a chassis and a body. Each suspension assembly itself is made up of a number of suspension components such as axle housings, beams, springs, damping components and bearings. Under loading conditions, these suspension components will move relative to each other and also relative to the chassis or body."
- The Patent goes on to explain how prior art on-board devices for indicating the state of loading of a vehicle exploited the movement between individual suspension components, or between a component and the chassis or body, when a load is applied to the vehicle.
" Early weighing systems to indicate axle or vehicle overloading rely on sensors which react to the movement of one of these components relative to another of these components within the suspension assembly or one of these components relative to the chassis or body. These early weighing systems therefore rely on a dynamic device which is attached physically to a number of components that move relative to each other in order to indicate the relative position of one component to another. The dynamic device may be considered as a two (or more) part device and the extent to which parts move (or are affected by the movement of other parts) can be related to the payload weight. One such device is disclosed in US-A-6566864. A conventional weighing system of this type is adversely affected by the very harsh environmental conditions in which it is installed and special measures are required to enable adequate sealing or shielding of the device in service. The weighing system is inherently susceptible to damage from large resilient objects caught or thrown up from a road surface. A device can be damaged if the axle or wheel encounters an over-travel event not typically seen in service (such as travelling on a particularly poor surface or as a result of vehicle collision)."
- An important point to note about the acknowledged prior art is that each device is attached to at least two components of the vehicle. It is the movement of these components relative to one another, caused by application of the load to the vehicle, which the device translates into a signal. The greater the relative movement, the stronger the signal and in turn the higher the reading on a meter or other suitable indicator of load.
- It was common ground that there were two means by which a device could detect relative motion of vehicle components. The first was linear, i.e. the device simply detected the change in linear distance between the components. The second was angular. Such devices had what could be thought of as arms joined at a common pivot. Each arm, at a part distant from the pivot, was attached to a vehicle component. As the components moved relative to one another due to a load being applied to the vehicle the angle between the arms was caused to change. The device generated a signal proportionate to the degree of angle change and thus gave an indication of the size of the load.
- Having described the prior art the Patent goes on to set out the invention. It is the idea of measuring the load applied to a vehicle by using a device attached to only one component of the vehicle, specifically a component of the suspension assembly. The device exploits the angular deflection of such a component when a load is applied to the vehicle. An example is shown in figure 4 of the Patent: a strut is joined by bearings at one end to the wheel hub assembly, which is supported by the spring damper assembly, and to the chassis at the other. When a load is applied, the hub and the chassis move vertically relative to each other and the strut joining them is caused to change its angle to the vertical. The device is fixed to the strut. It can detect a change of its angle relative to the vertical or horizontal and generates a signal which is proportional to the degree of change. This signal is taken also to be broadly proportional to the load applied to the vehicle and is used to create a reading for that load on a suitable display.
- The device is referred to in the specification as a 'transducer'. In claim 1 it is referred to as an 'inclinometer or accelerometer'. Dr Lloyd Davis, who acted as expert witness for VPG, explained that in the context of the Patent electrical (as opposed to mechanical) inclinometers and accelerometers were relevant and that the means for measuring inclination and acceleration respectively are closely related. I need not distinguish the two. As to their function it is enough for me to quote the following from Dr Davis's report:
"112. It is the purpose of an inclinometer to generate a reference plane (internally within the device), be that vertical or horizontal, and then measure the degree of difference between that plane and the body to which the instrument is attached."
- The specification introduces the claimed invention in the following way:
" The present invention relates to a system for indicating the state of loading of a vehicle which exploits a transducer intimately mounted on or attached to a suspension component of a suspension assembly.
 Thus viewed from one aspect the present invention provides a system for indicating the state of loading of a vehicle having suspension components comprising:
a transducer mountable on a single suspension component such that a signal relating to the angular deflection of the suspension component can be generated; and
a controller configured to receive the signal and generate an output representative of the state of loading of the vehicle.
 The system of the invention has the advantage that the transducer is mountable on a single suspension component and does not suffer the disadvantages occasioned by debris and is resilient to over-travel events. There are also no disadvantages as are typically experienced with systems of the prior art whereby mechanical wear can be a significant drawback and the connecting portions of two or more pieces require sealing."
- The inclinometer may be mounted on any of a number of alternative suspension components, such as a strut, a leaf spring or a trailing arm of the suspension assembly (see paragraph 24).
- The signal delivered by the inclinometer may be affected by the inclination (longitudinal angle to the horizontal) or attitude (transverse angle to the horizontal) of the vehicle as whole. At paragraphs 14 and 15 the Patent discusses preferred embodiments of the claimed system which include reference devices to measure inclination or attitude, as the case may be, which measurements are used to adjust, and by implication render more accurate, the value given by the inclinometer. Paragraph 14 says this:
" The system may include a reference device capable of measuring the angle of inclination of the vehicle chassis or body. A knowledge of the angle of inclination of the vehicle chassis or body may be used to adjust the value of the angles measured by the transducers to allow use of the system on ground that is not level (ie on an incline)."
- Claim 1 is as follows, divided into the integers adopted by both parties:
(a) A system for indicating the state of loading of a vehicle having suspension components comprising:
(b) a single suspension component of a coiled spring damper combination suspension assembly, a leaf spring suspension assembly, a trailing arm type suspension assembly or a rubber suspension assembly;
(c) at least one inclinometer or accelerometer mounted on the single suspension component,
(d) the inclinometer or accelerometer being configured to measure an angular deflection of said suspension component;
(e) a controller configured to generate an output signal representative of the state of loading of the vehicle,
(f) wherein the controller is configured to use the measured angular deflection to generate the output signal and
(g) a sensory output device for indicating the state of loading in response to the output signal of the controller.
Construction of claim 1
- A point of contention was the meaning of 'suspension component'. This has relevance when it comes to consider one of the items of prior art. The particular point is whether a 'suspension component' includes a component which is either the hub or part of the hub assembly. Neither expert took the view that as a matter of general usage the hub or any of the hub assembly would be part of the suspension. On the other hand, neither asserted that 'suspension component' was a term of art with a strict definition that would necessarily exclude the hub assembly from being part of the suspension components. Both gave views as to what the skilled person would understand the term to mean by reference to the Patent, but that was a matter for argument.
- Mr Hughes contended that 'suspension component' could not be part of anything that was in relation to the hub. He focussed on paragraph 38 of the Patent and in particular this sentence (reference numerals omitted):
"The spring damper assembly and struts which are components of the suspension assembly have bearings at each end allowing constrained movement of the hub."
Mr Hughes' point was that 'hub' and 'components of the suspension' are in that sentence treated as distinct, so the hub cannot have been intended to be a suspension component. I am not sure this works as a matter of general construction. Certainly the spring damper assembly and the struts are said to be components of the suspension assembly, but not the only ones. There is nothing in that sentence which perforce excludes the hub from also being a component of the suspension.
- Mr St Ville relied on paragraph 3 of the specification, quoted above. The first sentence divides a commercial vehicle into three major components: (i) multi-component suspension assemblies, (ii) a chassis and (iii) a body. The third sentence explains that under loading the suspension components will move relative to each other and also relative to the chassis or body. This would be true of the hub. The second sentence of paragraph 3 provides a list of suspension components, which does not include the hub but which is non-exclusive so there is no necessary reason to exclude 'hub' from the list.
- Beginning with the words of claim 1 itself, integer (a) (see above) requires the system to have suspension components. Either the system or the suspension components must comprise 'a single suspension component' of one of the four assemblies specified in integer (b), i.e. either a coiled spring damper combination assembly, a leaf spring suspension assembly, a trailing arm type suspension assembly or a rubber suspension assembly. The suspension component of integer (b) is also that of integer (c) – it is the suspension component on which the inclinometer or accelerometer is mounted.
- Paragraph 13 of the specification states:
" The transducer may be a static device. The transducer is or incorporates an inclinometer or accelerometer. The transducer may be mountable close to a vehicle axle. The suspension component is a component of a rubber suspension assembly, a trailing arm-type suspension assembly, a leaf-spring suspension assembly or a coiled spring damper suspension assembly."
- The final sentence suggests that the inclinometer must be mounted on a suspension component which forms part of one of the four stated suspension assemblies. There may be room for taking the view that the skilled person would construe the claim to cover alternative and equivalent suspension components, if such exist. I leave that to one side because the point was not raised and it makes no difference to the arguments raised before me which, although concerned with whether the hub could be part of the suspension system generally, I take to apply equally and specifically to each of the four suspension assemblies identified in integer (b). I will assume in this judgment that all vehicles have at least one of the four specified suspension assemblies.
- Although not put quite this way, I take AEL's argument to be that irrespective of which of the four assemblies may be used in a vehicle, the hub would be understood by the skilled person to form part of that assembly. VPG argues to the contrary.
- It was common ground that any part of the chassis and body would be excluded from the term 'suspension component'. So would any part of the drive train – see paragraphs 38 and 46. Although those paragraphs refer to the figure of the Patent, neither expert seemed willing to stretch 'suspension component' to form any part of the drive train. In my view, despite initial misgivings about whether a part of a vehicle which could be described as being 'in relation to a hub' of the vehicle could be a suspension component, the skilled person would adopt a purposive construction of that term. The purpose of a suspension component from the point of view of performing the invention is to be susceptible to variation in its angle relative to the vertical or horizontal when the vehicle is loaded. Then it can accommodate an inclinometer or accelerometer which will function as required by the invention. For that reason I think that the skilled person would not adopt an overly strict definition of the term 'suspension component' and include within its meaning any component outside the chassis, body and drive train which will fulfil the function just described.
Minimum accuracy of the claim 1 system
- A second point of construction emerged during the trial. Is the system claimed in claim 1 limited to any minimum standard of accuracy in its indication of the state of loading of the vehicle? This assumed significance in the context of distinguishing claim 1 over the closest prior art. Mr Hughes dealt with the point as part of his submissions regarding the final stage of the structured analysis of obviousness in Pozzoli SpA v BDMO SA  EWCA Civ 588;  FSR 37, at . I turn to Pozzoli shortly. However, although not the subject of submissions, it seems to me there is a point of construction that should be addressed.
- Integer (g) of claim 1 requires that the sensory output device is for indicating the state of loading of the vehicle in response to the output signal of the controller. According to the usual rules of patent construction, the sensory output device must be suitable for that purpose. The device itself must be functionally capable of indicating the state of loading, but in my view the skilled person would expect the system as a whole to be sensitive enough to indicate the state of loading of a vehicle and claim 1 to be limited accordingly. This may not be much of a limitation. The sensory output device need only be a flashing strobe light or siren (page 6, line 11) which implies enough sensitivity to detect a load that is dangerously heavy. Moreover there is no limitation in claim 1 which excludes from its scope systems which are commercially unattractive.
The law in relation to inventive step
- Both parties addressed the issue of inventive step according to the structured approach set out by Jacob LJ in Pozzoli SpA v BDMO SA  EWCA Civ 588;  FSR 37, at :
"(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?"
The person skilled in the art
- There was a dispute about the technical field from which the skilled person is drawn. VPG's case was that he or she came from the vehicle on-board weighing industry. This is one of the several industrial sectors which serve the motor industry, producing equipment for installation into vehicles. This sector produces devices of various kinds to measure the loading of a vehicle. If this is right, by implication the common general knowledge of the skilled person is confined to that derived from this particular sector.
- AEL suggested that the relevant field of the skilled person, or possibly team, was the on-board weighing industry and the automotive industry generally. In his expert report Michael Baker, expert for AEL, said that this was because the skilled team encompassed both (a) those likely to have a practical interest in the subject matter of the invention and also (b) those from the field of the problem which the invention claimed was trying to solve.
- Generally it is sufficient to identify the skilled person as the person who is likely to have a practical interest in the subject matter of the invention and practical knowledge and experience of the kind of work in which the invention is intended to be used, see Catnic Components Ltd v Hill & Smith  R.P.C. 183, at 242-3. That characterisation will always apply where the court is considering construction of the patent or an allegation of insufficiency. On certain facts such a characterisation will be inappropriate for the skilled person enrolled to assess inventive step, see Schlumberger Holdings Ltd v Electromagnetic Geoservices AS  EWCA Civ 819;  RPC 23. This seems to have been what AEL had in mind. In Environmental Defence Systems Ltd v Synergy Health plc  EWHC 1306 (IPEC);  FSR 6, at - I considered the care which sometimes needs to be taken in identifying the technical field from which the skilled person is drawn for the purpose of assessing inventive step.
- In the present case, though, I see no real difficulties that need teasing out. The technical field of the invention claimed and that of the prior art are the same. In cross-examination Mr Baker said that vehicle on-board weighing systems were manufactured by specialist suppliers to the automotive industry, albeit in consultation with the customer vehicle manufacturer. I take the view that the skilled person is an individual who designs on-board weighing systems and therefore works for a supplier to the automotive industry. He (to be taken to include she) will have knowledge not just derived from experience in the on-board weighing field but also of the automotive industry more generally as would be derived from regular consultations with those working in that industry. The skilled person has the usual characteristics of ordinary skill and no inventive capacity. It is likely that he would have one or more technical qualifications, probably an HND rather than an engineering degree, but this is not an instance in which the precise educational attainment of the skilled person matters.
The skilled person's common general knowledge
- On the evidence before me, the following would have been part of the skilled person's basic stock of reliable information drawn from his technical field of expertise. As such it would have formed part of the common general knowledge in the art:
(i) On-board systems for indicating the state of loading of a vehicle, in every case based on a device attached to two components of the vehicle ("double attachment devices").
(ii) A wide range of alternative means could be installed in a vehicle which would serve to measure its loading including load cells, air pressure transducers, strain gauges, linear displacement transducers, rotary displacement transducers, inclinometers and accelerometers.
(iii) Some of these means directly measured the force applied by the load, such as a load cell. Others measured the force indirectly by measuring the change in angle of a component of the vehicle when the load is applied.
(iv) The use of an inclinometer, attached to one component of the vehicle, as a reference device to measure the inclination or attitude of the vehicle and to compensate for it by adjusting the reading given by the means which measured loading. In some cases the means was turned off if the vehicle inclined beyond a certain angle.
(v) In-cab displays of the vehicle load.
The inventive concept
- The steps for assessing obviousness in Pozzoli are, as Jacob LJ indicated, an elaboration on the four steps earlier proposed by Oliver LJ Windsurfing International Inc v Tabur Marine (Great Britain) Ltd  R.P.C. 59:
"There are, we think, four steps which require to be taken in answering the jury question [as to obviousness]. The first is to identify the inventive concept embodied in the patent in suit. Thereafter, the court has to assume the mantle of the normally skilled but unimaginative addressee in the art at the priority date and to impute to him what was, at that date, common general knowledge in the art in question. The third step is to identify what, if any, differences exist between the matter cited as being "known or used" and the alleged invention. Finally, the court has to ask itself whether, viewed without any knowledge of the alleged invention, those differences constitute steps which would have been obvious to the skilled man or whether they require any degree of invention."
- Before Pozzoli Jacob J explained what was meant by the inventive concept in Unilever plc v Chefaro Proprietaries Ltd  R.P.C. 567, at 580:
"It is the 'inventive concept' of the claim in question which must be considered, not some generalised concept to be derived from the specification as a whole. Different claims can, and generally will, have different inventive concepts. The first stage of identification of the concept is likely to be a question of construction: what does the claim mean? It might be thought that there is no second stage – the concept is what the claim covers and that is that. But that is too wooden and not what courts applying Windsurfing stage one have done. It is too wooden because if one merely construes the claim one does not distinguish between portions which matter and portions which, although limitations on the ambit of the claim, do not. One is trying to identify the essence of the claim in this exercise."
- The inventive concept is not the same thing as the inventive step. The latter can vary according to the prior art under scrutiny whereas the former has only one identity for each claim. Identifying the essence of the claim and thus the inventive concept comes, in both the Windsurfing and Pozzoli analyses, before the prior art is addressed (see also Pozzoli at ). The inventive concept is therefore what the patentee asserts to be the essence of the invention as inferred from the words of the claim and the specification as a whole through the eyes of the skilled person. The skilled person will make the assessment with the common general knowledge of the relevant technical field in mind. It may be that one way of looking at the inventive concept is that it is the product or process claimed shorn of common general knowledge. If so, having the inventive concept defined at an early stage makes the later key stage of indentifying the inventive step a less cluttered assessment. This would only apply to the Pozzoli analysis. The third and fourth stages of the Windsurfing analysis require a comparison between the prior art and the alleged invention, which is the totality of what is claimed.
- There have been differing judicial views as to the importance of identifying the inventive concept. For example, Laddie J emphasised that it was important because identifying the inventive concept can reveal the vice of a claim which contains embodiments to which the inventive step does not apply, see Brugger v Medic-Aid Ltd  R.P.C. 635, at 656. By contrast in Pozzoli itself Jacob LJ indicated that coming to a concluded view on the inventive concept is optional, particularly when the parties cannot agree what it is or reaching a view on inventive concept would serve no useful purpose (at -). In Actavis UK Ltd v Novartis AG  FSR 18, Jacob LJ said this:
" I would only add an extra word about step 2 – identifying the inventive concept. It originally comes from Oliver L.J.'s formulation of the approach in Windsurfing International Inc v Tabur Marine (Great Britain) Ltd  R.P.C. 59 at 73. Strictly, the only thing that matters is what is claimed – as Lord Hoffmann said in Conor Medsystems Inc v Angiotech Pharmaceuticals Inc  UKHL 49;  RPC 28 at :
"The patentee is entitled to have the question of obviousness determined by reference to his claim and not to some vague paraphrase based upon the extent of his disclosure in the description."
 The "inventive concept" can be a distraction or helpful. It is a distraction almost as soon as there is an argument as to what it is. It is helpful when the parties are agreed as to what it is. In this case, for instance, although the claim has a numerical limitation defining what is meant by "sustained release", as a practical matter both sides proceeded on the basis that it was for a sustained release formulation of fluvastatin.
 The first three steps merely orientate the tribunal properly. Step 4 is the key, statutory step."
- Strictly, if the court does not define the inventive concept, the third and fourth stages of the Pozzoli analysis cannot be done. I believe what Jacob LJ had in mind was that if identifying the inventive concept is left out, one goes back to performing the third and fourth stages of the Windsurfing analysis.
- I take from this that depending on the facts and how each side presents its case, the court has the option of either defining the inventive concept and thereby streamlining the key stage of the analysis – the statutory assessment of inventive step – or alternatively it may leave out any identification of the inventive concept, in which case the prior art will be compared with the claimed invention as a whole. I will largely do the former, but cross-check the conclusion reached by also doing the latter.
- It is not in dispute that on-board systems for indicating the state of loading of a vehicle formed part of the common general knowledge, or that the vehicles had suspension components of one of the four types specified in integer (b) of claim 1. These systems used double attachment devices. It was also part of the common general knowledge that controllers could be used to generate an output signal from double attachment devices, the signal being representative of the state of loading of the vehicle, and that the signal could be used to indicate to the state of loading on a sensory output device to a user of the vehicle, such as a meter or other display.
- Separately, it was part of the common general knowledge to use a inclinometer or accelerometer attached to a component of a vehicle to measure the angular deflection of the vehicle, for the purpose of providing reference data to improve the performance of a double-attachment device.
- With this in mind, I take VPG's inventive concept to be the use of an inclinometer or accelerometer mounted on a single suspension component of a vehicle to generate a signal which is used to indicate the state of loading on a display.
- As I have stated, I think claim 1 is, at least on a literal reading, limited to mounting the inclinometer or accelerometer on a single suspension component which forms part of one of the four assemblies referred to in integer (b) of claim 1. The specification of the Patent does not lead me to think that this limitation is part of VPG's inventive concept. Neither party asserted that it is.
The prior art
- There were three cited items of prior art:
(i) European Patent No. 0625697 B1 ("Hi-Tech Scales");
(ii) US Patent No. 6,591,677 ("Rothoff"); and
(iii) A datasheet for the QG30 sensor from the Quadro range marketed by Dewit Industrial Sensors bv, the sensor being used for measuring (among other things) inclination ("the QG30 datasheet").
- Overwhelmingly attention was focussed on the second of these, Rothoff. Rothoff discloses a system for detecting the loading of a vehicle using an accelerometer.
- Rothoff begins with a discussion of the prior art, i.e. 'height-estimators' which detect the loading of a vehicle by measuring the distance between a sprung and unsprung part of the vehicle. These are said to be vulnerable to rough road conditions and to be difficult to install and calibrate. Rothoff continues:
"According to the invention there is provided a detecting system for detecting the loading of a vehicle, wherein the detecting system comprises at least one accelerometer in a first position and arranged in a predefined direction on said vehicle, wherein the acceleration of gravity in said pre-defined direction may be used as a reference value for the accelerometer and said accelerometer is arranged to detect the deviation of acceleration relative to said first position, said deviation being related to the loading of the vehicle." (col. 1, lines 51-59)
- One way in which the accelerometer can work is by detecting its angular displacement, i.e. its angular change from the vertical:
"In an embodiment of the invention the detected change in vertical acceleration relative to said first position is related to an angular displacement of the accelerometer from said first position, relative to a point, caused by the displacement of a vehicle due to the actual loading." (col. 2, lines 1-5)
- Rothoff gave details of preferred embodiments which led to debate:
"Preferably the accelerometer is arranged fixedly in relation to a hub of said vehicle and the change in camber and/or caster is detected. In a preferred embodiment the accelerometer is installed on a shaft of a spindle. Depending on the type of shaft the camber readings can be taken into account." (col. 2, lines 9-13, my underlining)
- Counsel on both sides indicated that I need be concerned only with camber, not caster. Camber relates to the wheels of a vehicle and is shown in figure 2 of Rothoff. It is the angle of variation from the vertical of a wheel. When a vehicle is loaded the top of the wheels tend to move inwards relative to the bottom of the wheels which are in contact with the ground. This causes the wheels to tilt from the vertical. The extent of that tilt is the camber. If an inclinometer/accelerometer is attached to the hub of a wheel, it too will tilt away from the vertical. The extent of tilt is related to the load and if measured can therefore be used to assess the load.
- The purpose of assessing the load of a vehicle contemplated by Rothoff is to allow automatic adjustment of the road clearance, springing and damping of the vehicle:
"The detecting system is preferably connected to a control unit in order to control the springing and damping behaviour of said vehicle. For this purpose the detecting system according to a preferred embodiment of the invention is connected to a spring and damper system of said vehicle. This arrangement makes it possible to detect the road clearance. In situations where the clearance is insufficient due to e.g. heavy carrying load or the fact that the vehicle passes an uneven spot on the road the spring and damper system of the vehicle can be activated in order to prevent damage." (col. 2, lines 39-49)
Rothoff is not concerned with informing users of a vehicle of the weight of its load.
- Rothoff expressly does not limit the claimed invention to a particular type of accelerometer/inclinometer fixed at a particular place on a vehicle:
"The exact shape, size and position on the vehicle of the accelerometers can also be modified as well as the type of accelerometer in order to meet specific requirements and are in the above only given as guidance." (col. 4, lines 27-30)
- The figures in Rothoff illustrate its system using a diagram of a passenger car, identified in the trial as a Volvo saloon. This reflects the primary concern of the specification with passenger cars. But the reader is told this:
"The detecting system is intended for all kinds of vehicles such as trucks, vans, tanks etc. and is not limited to a car as shown in FIG 1." (col. 4, lines 31-33)
The reference to 'tanks' was treated by both sides as surprising until Mr Baker, in cross-examination, helpfully pointed out the American origins of the Rothoff specification and said that 'tanks' is an Americanism for road tankers, such as oil tankers.
The difference between Rothoff and the inventive concept
- There was one agreed difference between Rothoff and the inventive concept as I have defined it and one in dispute. The acknowledged difference is that Rothoff does not disclose the use of the signal from the accelerometer to indicate the state of loading of the vehicle. The sole function of the accelerometer which is disclosed is to control the springing and damping behaviour of the vehicle.
- The difference that was in dispute came from this teaching in Rothoff:
"Preferably the accelerometer is arranged fixedly in relation to a hub of said vehicle and the change in camber and/or caster is detected."
There is no reference to fixing the accelerometer to a suspension component. I have found that on a purposive construction 'suspension component' will include any component outside the chassis, body and drive train which is susceptible to variation in its angle relative to the vertical or other reference direction when the vehicle is loaded. That would include a non-rotating part of the hub assembly. The experts were agreed, as was self-evident, that where Rothoff talked of arranging the accelerometer fixedly in relation to a hub it could not mean literally fixing it to a rotating hub, but to some non-rotating part of the hub assembly. On the construction of the Patent as I have found to be, this second difference falls away.
- The differences between Rothoff and claim 1 as a whole came down to the same two points and following my finding on construction, just one.
Whether the differences constitute steps which would have been obvious to the person skilled in the art
- I begin by addressing an argument advanced by Mr Hughes. He submitted that as a matter of law, commercial realities had to be taken into account at the final stage of the Pozzoli analysis. In other words I must assume that the skilled person's view of what is and what is not obvious is coloured by his knowledge of what will be commercially attractive. In the context of these proceedings I take this to mean that if the skilled person, having carefully read Rothoff, found the idea of a system as claimed in claim 1 of the Patent technically obvious but commercially unattractive and accordingly dismissed the idea of attempting to make such a system, the claimed invention would as a consequence not be obvious. I do not accept this.
- So far as I am aware, the closest a court has come to addressing the point was in Dyson Appliances Ltd v Hoover Ltd  EWCA Civ 1440;  RPC 22. At first glance, though only that, Aldous LJ seems to have been rejecting a contention made to the Court of Appeal that the commercial prejudices of the skilled person should never be taken into account:
" Mr Hobbs submitted that when considering obviousness the court was not concerned with commercial considerations such as the perceived "mindset" in favour of the use of bags, only technical matters were relevant. To support that submission he referred us to the judgment of Slade L.J. in Hallen Co. v. Brabantia (U.K.) Ltd  R.P.C. 195 at page 213 line 31:
"If the plea of obviousness is to succeed, the court has to be satisfied that it would have appeared to the hypothetical technician, skilled in the art but lacking in inventive capacity, worthwhile to coat the helix of a self-pulling corkscrew with a friction-reducing material for purpose (a) or purpose (b) above or both of them. As cases such as Technograph and Beecham show, he is not to be expected to take steps or try processes which he would not regard as worthwhile. In using the word 'worthwhile', we mean worthwhile as a possible means of achieving or assisting in practice the objective which he has in view. This, we infer, was what the judge had in mind in saying that the word 'obvious' in section 3 is directed to whether or not an advance is 'technically or practically obvious'. We do not think that the hypothetical technician must also be taken as applying his mind to the commercial consequences which might follow if the step or process in question were found in practice to achieve or assist the objective which he had in view. As Oliver L.J. said in the Windsurfing case,  R.P.C. 59 at page 72, 'What has to be determined is whether what is now claimed as inventive would have been obvious, not whether it would have appeared commercially worthwhile to exploit it'. We thus agree with the judge that the word 'obvious' in section 3 is not directed to whether an advance is 'commercially obvious'. We do not think that he misdirected himself in the relevant passage of his judgment."
Since at least the Hallen case, it has been recognised that the patent system is not available to protect mere commercial improvements. The observations of Slade L.J. were directed at that issue which is step four of the Windsurfing steps.
 I do not believe the judge fell into error in paragraph 156 of his judgment. The mantle of the skilled person is that of an actual skilled person. The purpose of assuming the mantle of the skilled person is to enable the decision as to what is obvious to be a decision based on actual facts. They include all the attitudes and perceptions of such a person."
- 'The attitudes and perceptions' of the skilled man that were in issue becomes clear from paragraph 156 of the judgment of Michael Fysh QC, sitting as a Deputy Judge of the Patents Court, at first instance:
"A Prejudice in favour of bags
 In paragraphs 30–47, I have recorded my findings with regard to the hypothetical skilled addressee and the common general knowledge to be attributed to the addressee at the relevant time. I wish however to add this. Common general knowledge has both positive and negative aspects. I have so far considered under this topic, as is customary, only positive aspects of the knowledge with which the skilled addressee is to be imbued. In my view in certain cases (and I believe this to be one of them), negative aspects of knowledge must in approximation to reality, play their part. At the priority date of the patent, I believe that such as the "mindset" within the vacuum cleaner industry, no notional, right-thinking addressee would ever have considered the viability of purifying dirt-laden air from a vacuum cleaning operation, other than by means of using a bag or bag and final filter. For present purposes, the addressee is nonetheless deemed to have been presented with (in effect) three items of prior art wherein it is proposed to clean dirt-laden air by means not of bags but by cyclonic action alone. He is also assumed to take some interest in them however inimical the proposals may be to his likely way of thinking at the time. In terms of its impact on the issue of obviousness, I believe that this negative thinking which as Mr Kitchin suggested amounted to prejudice, would at least have caused the addressee to regard modification to any of these prior art proposals with considerable reserve if not overt scepticism. This likelihood must, I consider, be given due weight. In my view of the matter, I cannot think that any of the cited prior art would ex facie be likely to have lead the addressee at the relevant date with any enthusiasm to effect the often substantial changes which would bring these proposals within a claim of the patent: see para. 153. My view in this regard is bolstered (but not precipitated) by Mr Dyson's evidence of what actually happened when he tried to interest the industry in Dyson I."
- I entirely accept that the skilled person must be taken to have in mind all the concerns and prejudices held by those in his field. But only technical ones. I can see nothing in Dyson which supports Mr Hughes' proposition that commercial prejudices are also to be considered. Furthermore, to do so would go against what was said by the Court of Appeal in Hallen.
- That takes me to whether it was obvious, in the light of Rothoff, to use the signal from the accelerometer to indicate to a user of the vehicle or other person the state of loading of the vehicle.
- Mr Hughes submitted that the skilled person would find Rothoff so off-putting that he would not consider it to be a sound basis for creating a system as claimed in the Patent. His reasons were these:
(1) The system in Rothoff relies on the change of camber of the wheels when the vehicle is loaded to alter the angle of the accelerometer, which is arranged fixedly in relation to a hub. The change in camber will depend on the position of the wheels.
(2) Rothoff speaks of 'estimating' the loading of the vehicle.
(3) Vehicles heavier than a family saloon are designed to minimise camber, so the change in angle of an accelerometer fixed in relation to the hub assembly would change little.
(4) Rothoff teaches arranging the accelerometer fixedly in relation to a hub, which would be impossible because the hub rotates.
(5) The figures in Rothoff show the accelerometer attached not to the hub itself but to a backing plate or shield for the hub.
(6) In a preferred embodiment Rothoff refers to installing the accelerometer on the shaft of a spindle. Dr Davis said this was unclear and not illustrated in the figures.
(7) Rothoff refers to measuring how loading affects the angle of a sprung part of the vehicle, whereas the hub and hub assembly are not part of the sprung part of the vehicle.
(8) The figures given in Rothoff for the output signal of the accelerometer suggest that these are accelerometers with a non-linear response curve. This would introduce an unwelcome complexity into the system.
(9) The indication of accuracy given in the Rothoff specification makes no sense. It states
"When measuring the downloading of the vehicle during standstill the accelerometer has accuracy in the range around one g where a deviation of 1 mm is detectable".
- This list may be quite long, but even cumulatively it was not established that they would lead the skilled person to reject the idea of adapting Rothoff to provide a system that indicated the loading of a vehicle, always assuming such an idea occurred to the skilled reader in the first place. I will go through the list.
(1)-(3) These go to the accuracy that the skilled person would expect of a system adapted from Rothoff to indicate the loading of a vehicle. In the case of (3), claim 1 of the Patent encompasses cars, not just trucks, so it is not relevant.
(4)-(6) The skilled person would not suppose that the accelerometer in Rothoff could be attached to the hub itself. The figures indicated that in fact Rothoff had in mind part of the hub assembly. The reference to a preferred embodiment in which the accelerometer is attached on a shaft of a spindle was, as the experts acknowledged, not as clear as it might be. But at most the skilled reader would ignore this embodiment.
(7) If anything, this objection seems to me to clarify matters in the mind of the skilled person. The Rothoff system is said to measure how loading affects the sprung part of the vehicle. Since the accelerometer is to be arranged in relation to the hub assembly, the skilled person is likely to realise that the hub assembly is being treated as included in the sprung part of the vehicle for the purpose of this document.
(8) This again goes to accuracy.
- I will take the final objection separately. Mr Baker suggested that the sentence I have quoted from Rothoff contained a typo and would be interpreted by the skilled person to mean:
"When measuring the downloading of the vehicle during standstill the accelerometer has accuracy in the range around one g where a deviation of 1
mm milli g is detectable".
Dr Davis agreed that this would make sense. He also said that it would suggest good accuracy. On that evidence I do not believe that the skilled person would be deterred from adapting Rothoff on grounds of lack of accuracy.
- Moreover it was common ground that however accurate and sensitive the inclinometer or accelerometer may be at detecting a change of angle, it is always in the nature of systems measuring a vehicle's load by such a change of angle that accuracy of the system as a whole is going to be limited. Expectations would not have been high. The experts explained that there is no simple relationship between the movement of the suspension system and the load applied to a vehicle. Mr Baker said that vehicles' suspension systems did not move in a neat and directly proportional relationship to the load applied to it. In particular he referred to a phenomenon known as 'hysterisis'. The position of the suspension system will generally be different if the load is increased to X kg than it would be if the load is decreased to X kg. That is because of an inbuilt resistance to a change in position. This will be equally true of the system claimed in the Patent, that disclosed in Rothoff, or any other.
- In cross-examination Mr Baker accepted that some of the matters in Rothoff which I have listed above would be perceived by the skilled person as off-putting. Mr Baker was not, however, deterred from his overall position that despite the shortcomings of Rothoff it would have been obvious for the skilled person to adapt it to make a system falling within claim 1 of the Patent.
- Dr Davis's principal reservation about Rothoff was that in his view it did not disclose use of an accelerometer/inclinometer on a suspension component. He also refused to be drawn on whether the skilled person would consider adapting Rothoff to use a visual display. As to the latter, since it was an agreed part of the common general knowledge that double attachment devices had visual displays, I accept Mr Baker's view that this is indeed something that the skilled person would have contemplated as a possible variation on Rothoff.
- Given my view on the correct construction of claim 1, Dr Davis's principal reservation falls away. I should add that even if the skilled person would not have interpreted 'suspension components' to include the hub or hub assembly, I would have reached the view that the skilled person, having read Rothoff, would have found it obvious to attach the accelerometer to a suspension component. First, Rothoff expressly states that the position of the accelerometer can be changed in order to meet specific requirements. Secondly, the skilled person would have known that the function of the accelerometer is to provide a signal in response to angle change caused by the loading of the vehicle. The skilled person would in my view have recognised that the accelerometer should be located in a place that allowed it to fulfil this function, rather than being overly concerned about whether that place was strictly part of the hub assembly.
Hi-Tech Scales and the QG30 datasheet
- Mr St Ville only referred to the other two pieces of prior art for a limited purpose. He relied on Hi-Tech Scales to show that the skilled person wishing to measure the angular displacement of the suspension would have thought it obvious to use an inclinometer. The inclinometer of the QG30 datasheet would have been an obvious one to use. They seem to me to make no real difference.
No long felt want advanced
- I would only add this. No argument of long felt want was run by VPG. Superficially one might have expected an argument of that kind in these proceedings. The evidence from the experts suggested that this was a field in which the performance of inclinometers and accelerometers was advancing at quite a rapid rate in the period leading up to the Patent's priority date. Had long felt want been run, it is possible that it was around 2006 when such advances made a system of the type claimed in the Patent commercially attractive. As it is, long felt want was not enrolled to assist VPG's case so the change in performance of inclinometers is neutral.
- Claims 1 and 7 of the Patent are invalid for lack of inventive step over Rothoff.