Improver Corp v Remington Consumer Products Ltd
The Catnic approach to claim construction was restated as three questions about whether a variant has a material effect, whether that would have been obvious, and whether the patentee intended strict compliance.
Facts
Improver held a patent for a hair removing device, the Epilady, which used a rotating helical spring to pluck hairs from the skin. Remington made a similar device, which used a rotating rubber rod with slits in it instead of a spring. Improver sued for infringement, arguing that the rubber rod was equivalent to the helical spring.
Legal principle
Hoffmann J held that Remington had not infringed the patent. He restated the Catnic test in three questions: first, does the variant have a material effect upon the way the invention works; if not, second, would this have been obvious at the date of publication of the patent to a reader skilled in the art; if so, third, would the reader skilled in the art nevertheless have understood from the language of the claim that the patentee intended that strict compliance with the primary meaning was an essential requirement of the invention. He found that the skilled reader would have understood that the claim to a helical spring was not intended to cover a rubber rod. These questions became known as the Protocol questions.
Related cases on patents: claim construction and infringement
- Actavis UK Ltd v Eli Lilly & Co [2017] UKSC 48
- Catnic Components Ltd v Hill & Smith Ltd [1982] RPC 183
- Gillette Safety Razor Co v Anglo-American Trading Co Ltd (1913) 30 RPC 465
- Grimme Maschinenfabrik GmbH & Co KG v Scott [2010] EWCA Civ 1110, [2011] FSR 7
- Kirin-Amgen Inc v Hoechst Marion Roussel Ltd [2004] UKHL 46, [2005] RPC 9
- Monsanto Technology LLC v Cefetra BV Case C-428/08, [2010] ECR I-6765
- Schütz (UK) Ltd v Werit (UK) Ltd [2013] UKSC 16, [2013] RPC 16
- Smith Kline & French Laboratories Ltd v Evans Medical Ltd [1989] FSR 513
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