Case: Catnic Components Ltd v Hill &amp; Smith Ltd [1982] RPC 183
Outcome: cited
a purposive approach to construction of the claims does not mean that clear limitations in the scope of the monopoly contained in the language of the claims can be avoided or the reach of the monopoly extended beyond the clear limits of the language selected. A purposive approach to construction as opposed to a purely literal one will raise the question of whether persons with practical knowledge and experience of the kind of work in which the invention was intended to be used, would understand that strict compliance with the descriptive words or phrases used in a claim was intended to be an essential requirement of the invention. If so, as a matter of construction, a variant would fall outside the monopoly claimed even though it could have no material affect on the way the invention works. That question does not arise where the variant would in fact have a material affect upon the way the invention works ( Catnic Components Ltd v Hill &amp; Smith Ltd [1982] RPC 183 ; Kirin-Amgen Inc. v Hoechst Marion Roussel Ltd (2004) 64 IPR 444). The construction of the language of a claim, adopted by the Court, ultimately determines infringement. The question is whether the alleged infringement is comprehended by the clear language of the claim ( Sachtler applying Catnic and PhotoCure ASA v Queen's University at Kingston [2005] FCA 344 ; (2005) 216 ALR 41). Construction of the claims The point of this discussion is that it may tell the Court something about construction of the claims. If the claims are confined to a single unitary reverse wound spring, might that integer be regarded as an inessential integer if there is no functional difference between a spring clutch that includes such a spring and a spring clutch that incorporates three separate springs in adjacent alignment reflecting alternate winding. Would persons with practical knowledge and experience in the subject matter addressed by the invention understand that strict compliance with a particular descriptive word or phrase appearing in a claim was intended by the patentee to be an essential requirement of the invention so that any variation would fall outside the monopoly claimed even though it could have no material affect upon the working of the invention. Lord Diplock in Catnic Components Ltd v Hill &amp; Smith Ltd (supra) noted that such a question would not arise where the variation would in fact have a material affect upon the working of the invention. The Improver or protocol questions ( Improver Corporation v Remington Consumer Products Ltd [1990] FSR 181) pose questions, the answers to which assist construction . That is to say, the questions test whether a reasonable person skilled in the art reading the language of the claims in context would think that the patentee was intending to confine the monopoly to the natural or primary meaning of the words selected or, alternatively, would such a person think that the patentee was intending to include within that meaning a variant of no material functional difference ( Root Quality Pty Ltd v Root Control Technologies Pty Ltd [2000] FCA 980 ; (2000) 177 ALR 231). Mr Hunter and SBriggs concede that claims1, 2, 8, 10 and 11 of the patent in suit have been anticipated by reason of figure 12 in US Patent 643 (Table A, para 38, Hunter affidavit, 6 March 2008). Figure 12 shows two helical springs of reverse winding. At column 7, line 8 of US Patent 643, a reference is made to a complex arrangement of interleaved springs which will afford the advantages of the invention. An example is given of three springs which could be interleaved and used with a housing engaging three keys placed in a particular way. At line 13 of column 7, another way is described to bring the tabs of a spring close together. The specification says this: Yet another way to bring the spring tangs [another word which describes tabs of a spring] close together along the spring axis is to use two springs, one spring wound with a clockwise helix , and the other with a counterclockwise helix . FIG 12 depicts a possible spring configuration for such a spring. These springs could be used in place of springs 95 and 97 of the clutch of FIGS 10 and 11 to provide the benefit of our invention for loading in one direction. [emphasis added] The above reference suggests that two springs of reverse winding might be used in the depiction in the Figure 10 drawing. Figures 10 and 12 are Schedules 7 and 8 to these reasons. Claim 1 of US Patent 643 is in these terms: 1. A spring clutch for lowering and raising a window shade comprising: a shaft; at least first and second helically wound axially mounted springs having first and second ends for making frictional contact with the shaft; first engaging means corresponding to each of said at least first and second springs for selectively applying a tightening force to one of the said ends of each of said springs for inhibiting rotation thereof with respect to said shaft; second engaging means for selectively applying a loosening force to the other of the said ends of each of said springs for promoting rotation thereof with respect to said shaft; wherein each of said first engaging means is radially and symmetrically disposed about said shaft for substantially eliminating radial bearing forces.