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  • Writer's pictureYork Faulkner

Patent Specification’s Narrow Description Disavows Claims to Alternative Variations of the Invention

Updated: May 27, 2021

In Wastow Enterprises, LLC v., Inc. et al., No. 2020-2349 (Fed. Cir. May 14, 2021), the U.S. Court of Appeals for the Federal Circuit, affirmed the district court’s patent claim construction—effectively ending Wastow’s patent infringement case against Truckmovers.

The court’s claim construction ruling limited all variations of the claimed vehicle towing systems to devices having “a universal folding boom trailer”—including claims that nowhere recite “a universal folding boom trailer” as a claim element. The district court found and the Federal Circuit agreed that Wastow had disavowed all towing systems that do not have “a universal folding boom trailer.” Lacking evidence that Truckmover’s towing systems utilize “a universal folding boom trailer,” Wastow stipulated to a judgment of non-infringement under the district court’s claim construction ruling.

Courts have traditionally imposed a high threshold for proving disavowed claim scope, requiring evidence that the patentee “specifically excluded” certain embodiments of the invention. See Abbott Labs. v. Andrx Pharms., Inc., 473 F.3d 1196, 1211 (Fed. Cir. 2007). The Federal Circuit has similarly explained that disavowal requires proof a “clear and unmistakable surrender.” See Abraxis Bioscience, Inc. v. Mayne Pharma (USA) Inc., 467 F.3d 1370, 1381 (Fed. Cir. 2004); see also SciMed Life Systems, Inc. v. Advanced Cardiovascular Systems, Inc., 242 F.3d 1337, 1347 (Fed. Cir. 2001) (“clear and binding statement to the public”).

Under such elevated evidentiary requirements, courts typically base disavowal rulings on patentee expressions of what the invention is NOT rather than on descriptions of what the invention IS. For example, statements in a patent’s specification disparaging certain prior art features while touting the inventions’ alternatives to those features have been found to disavow the disparaged features, placing them outside the claimed scope of the invention. See, e.g., SciMed Life Systems, 242 F.3d at 1342-43 (derogation of “dual lumen” catheters); Tronzo v. Biomet, Inc., 156 F.3d 1154, 1159 (Fed. Cir. 1998) (“inferior” non-conical shaped cup for artificial hip).

Wastow made no such disclaimers of specific prior art features or embodiments—neither in the patent’s specification nor during prosecution of the patent application. Rather, the district court based its claim-limiting disavowal ruling on the patent specification’s insistence on describing a “universal folding boom trailer” as a central feature of the invention.

The district court explained that “[a]lthough there was no explicit disavowal of other devices, the patentees description of the ‘the present invention’ as referring to a universal folding boom trailer and the repeated, consistent use of the complete term ‘universal folding boom trailer’ to refer to the claimed device together support the conclusion that the patentee implicitly disavowed claim terms lacking a ‘universal folding boom trailer.’” Wastow Enters. v., Inc., No. 4:19-cv-00249-NKL *7 (W.D. Missouri May 26, 2020) (emphasis added). The district court therefore construed the term “device” appearing in the patent’s claim preambles as referring to a “universal folding boom trailer.” Id. at *2.

The Federal Circuit was likewise persuaded that the specification’s repeated “[description of] ‘the present invention’ as a universal folding boom trailer” evidences an implicit disavowal of any other variation of the invention. Wastow Enter., No. 2020-2349 at 6. The court further reasoned that “[t]he patent’s title—‘Universal Folding Boom Trailer’—also indicates that a relevant artisan would understand that the claims require a universal folding boom trailer.” Id. at 7. The court also observed that the specification failed to use the phrase “the present invention” together with such non-limiting talismans as “one technique,” “can be carried out,” and “a way” when discussing preferred embodiments of the invention. Id. at 8.

This is not the first time that a patent specification’s overly narrow description of the invention resulted in a disavowal of claim scope. The Federal Circuit noted that it elsewhere explained that “‘an inventor may disavow claims lacking a particular feature when the specification describes ‘the present invention’ as having that feature.’” Id. at 5-6 quoting Poly-America, L.P. v. API Indus., Inc., 839 F.3d 1131, 1136 (Fed. Cir. 2016); also citing Luminara Worldwide, LLC v. Liown Elecs. Co., 814 F.3d 1343, 1353 (Fed. Cir. 2016) (disavowal resulting from such expressions as “the present invention includes” and “the present invention is”).

This case, therefore, is one of a growing number of cautionary examples to patent drafters of the risks inherent in narrow descriptions of the invention. Much attention is ordinarily given to precision in claim drafting and care is exercised during prosecution of the application to avoid disclaiming certain embodiments of the invention. In the end, however, the patent’s specification becomes not only the focus of claim construction but also the best evidentiary expression of the inventor’s intent such that it “may reveal an intentional disclaimer, or disavowal, of claim scope by the inventor [which] . . . is regarded as dispositive.” Phillips v. AWH Corp., 415 F.3d 1303, 1312-17 (Fed. Cir. 2005).

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