Effective Specification Drafting - The Case Study Based on A WindSurfer Patent (continued)

Technical features - I - identification of a single novel feature

In most cases the applicant will require the broadest available†Protection17, and for that purpose it will usually be appropriate to file main †independent claims based on a single novel feature that introduces an advantage†and hence is arguably inventive.

Initial attention was focused on the unsupported pivoted mast that was†held upright by a user to sail the board. Embodiments of the pivot could have a †single axis, two axes or three axes. On the premise that it is best to start with the†minimum difference from the known prior art, i.e. the Sailfish/Sunfish sailboards,†it would have been logical at the initial filing stage to cover pivoting about a†single axis. One starting point statement of invention could therefore have been†based on a board having a sailing rig including firstly an unsupported mast †pivotally attachable to the board for movement about at least one axis and†secondly hand control means for grasping by a user for positioning the mast. The†US versions of the Windsurfer patent preserve the broadest definition of the†invention as originally filed, and refer to "wind propulsion means pivotally†associated with the body means and adapted to receive wind for motive power." †The word pivotally in the above statement covers all three possibilities for the†number of pivot axes. From this definition, it would have been possible to†reconstruct a technical problem, treating the Sailfish/Sunfish sailboards as closest†known prior art, of providing a sailboard whose control demands new skills and†that provided a greater sensation of speed and excitement.

The inventors might have objected to such a broad statements of†invention based on their experience with their unsatisfactory Skate prototype in†which the mast and sail were pivoted only for movement in a fore and aft plane.†In that prototype, heeling movements of the sail were transmitted to the board †and made it impossible for the user to stand on the board, so that Skate was never†sailed. However, the patent attorney could have replied that Skate used a†surfboard hull and was therefore of low roll stability. If the inventors intended to†cover other sailing craft, their heavier and deeper hulls might provide sufficient†roll stability for control from a standing position. Part of the task of the patent †attorney is to seek protection covering versions of the invention that use only†some features of the preferred embodiment, thereby sacrificing some but not all†of the benefits obtainable. Limiting the claims to multi-axis pivoting at the initial†filing stage would have been unwise because of the risk that a third party would†find a way of making single-axis pivoting practical.

In the disclosed embodiment pivoting the mast in the fore and aft plane†appeared to be the most important because it facilitated steering. Providing an†additional axis for pivoting the mast in a plane transversely of the hull prevented†heeling forces on the sail from being transmitted via the mast to the hull which †though advantageous was arguably less critical. Permitting the mast to rotate†about its axis relative to the hull becomes advantageous where the sail is attached†to the mast by a sock and is stiffened by battens so that the actions of pulling the†sail in or letting the sail out tend to rotate the mast. In the prototypes where the†booms are pivoted to the mast and the sail is wholly of flexible cloth the mast †rotation feature may be a non-critical refinement. One useful subsidiary claim†could therefore have specified that the sailing rig was pivotally attachable to the†board for movement in at least a plane aligned with the fore and aft direction of†the board, with the supporting advantage that the hand control means could be†used to steer the board towards or away from the apparent wind by manual †adjustment of the mast position in said fore-and aft plane18. Further subsidiary†claims could have introduced the second and third pivot axes, with their†associated advantages being explained in the description.

Technical features - II - arcuate booms

Arcuate for the shape of the booms provides an example of the use of an†unexplained structural definition where a functional definition would have been†more effective. The meaning of arcuate became critical in the UK infringement†proceedings because it provided the only available distinction from another prior †sailing craft19 that had been found by the defendants. It used a split boom formed†from straight pieces of wood that became curved to some extent when the craft†was being sailed. The only purposes disclosed in the patent for the arcuate†booms were to provide a grip for the user and to hold the sail taught. Straight†booms achieved these purposes equally effectively. The Court refused to take †notice of the fact that the booms were shaped and curved so that the sail would†take up an aerofoil shape because such a requirement was neither discussed in†the specific description nor a feature of any dependent claim, and the fact that the†feature might be discerned by inspection of the drawing was not persuasive.

Structural claims often suffer from the problem that they are narrow and†easily circumvented, especially when they introduce a geometrical feature. In the†US, the classic case is Winans v Denmead20 , where the patentee claimed a†railway truck for transporting coal. It had a coal hopper of inverted frustoconical†shape to give a relatively small base that could extend below the frame of the†truck and between its axles to give a low centre of gravity. The defendant's truck†was similar, except that their hopper had the form of a hexagonal pyramid i.e. it †had a number of straight walls instead of the required single curved wall. The†resulting infringement controversy reached the US Supreme Court before it was†finally resolved in the patentee's favour. In the UK, the classic case is Catnic v†Hill & Smith21 in which the patentee claimed a vertical wall in a lintel structure†and the alleged infringement had a wall inclined at a few degrees to the vertical. †Again, the resulting infringement controversy was litigated as far as the House of†Lords, and infringement was established only on the basis of a widened or†"purposive" construction of the claim language. That language cannot be†regarded as successful if infringement can only be established on appeal to the†highest court in the relevant jurisdiction. In the case of the Windsurfer patent, it †was foreseeable that third parties might design a split boom arrangement in†which the booms were spaced to give the sail sufficient space to take up its†natural aerofoil shape, but that were not arcuate. An example appears from Fig. 9†which is taken from a third party patent22 that formed part of the Windsurfer†licensing package considered by the EU Commission. If an unauthorised third †party had adopted such a triangular boom structure, there would have been no†literal adoption of the arcuate claim language, and proof of infringement on the†basis of a widened "purposive construction" of that language would have been†difficult.

Technical features - III - body means

The reference to "body means" in claim 1 of the UK patent is not further †qualified in any of the subsidiary claims. In the description the hull is merely†referred to as a "surfboard" without further explanation. It therefore appears that†the inventors or their attorneys were of the opinion that the board either was not†novel or differed from known sailboards only in such minor details as to provide†no contribution to the invention. That was also the opinion of the German Patent †Office, which after being notified about references disclosing wishbone rigs and†about the Darby sailboard allowed a claim to the rig but refused a claim to the†rig/board combination on the ground that the board contributed nothing novel.

Windsurfer had a policy of granting licenses to manufacture boards only †on condition that they were supplied together with rigs. The EU Commission†objected to this policy on the ground that a patent should not be used to restrict†competition in the boards which were not covered by the claims of the German†patent, and their objection was upheld on appeal to the EU Court23 . The same†view about the separate novelty of the board and other components was taken in†proceedings for infringement of the corresponding Canadian patent24 , where the†Federal Court of Appeals said:

"No one has never alleged...

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