Finding that the patentee “failed to produce any evidence to the contrary,” the U.S. Court of Appeals for the Federal Circuit affirmed the district court’s finding that the patentee did not raise a genuine issue of material fact as to infringement of the patent directed to a hunting blind. Stumbo v. Eastman Outdoors, Case Nos. 2007-1186, -1205 (Fed. Cir., Nov. 28, 2007) (Moore, J.).

Steve Stumbo filed suit against Eastman Outdoors, Inc. and Ameristep Corp. for infringement of U.S. Patent No. 5,628,338 (the ’338 patent) directed to a hunting shelter or blind having a “closable vertical opening,” depicted as a slit opening at a side edge or vertical corner, through which a person can enter or exit the blind. The defendants’ accused products also included openings, albeit triangular-shaped openings. The defendants moved for summary judgment as to all of Stumbo’s claims, arguing that the accused products do not infringe the ’338 patent, either literally or under the doctrine of equivalents. The district court construed “closable vertical opening” as a “slit-like opening that runs straight up and down or perpendicular to the plane of the horizon.” The court concluded that, based on this construction, no genuine issue of material fact existed as to whether the accused products infringed the ’338 patent, literally or under the doctrine of equivalents. Stumbo appealed the district court’s decision to grant summary judgment of non-infringement

The Federal Circuit reviewed the district court’s summary judgment decision de novo, but did not turn a blind eye to the district court’s line of reasoning. The Court adopted the lower court’s construction of “closable vertical opening” and found that there was no dispute as to literal infringement under this construction. Under the doctrine of equivalents analysis, the Court found that the specification stated that leg members of the blind “must flex in order to enable the door opening to expand for ingress and egress.” Eastman Outdoors and Ameristep both offered testimonial evidence that the accused products do not have this structural limitation and do not operate in substantially the same way with substantially the same result. In dismissing a declaration submitted by Stumbo, the Court stated that Stumbo “has not produced a single shred of particularized evidence as to how the vertical opening of the ’338 patent creates substantially the same result [as the accused products].” The Court further stated that the conclusory declaration “did not explain how either opening operated or how the differences were insubstantial” and explained that “[h]aving failed to produce any evidence to the contrary, Stumbo has not raised a genuine issue of material fact as to infringement” by the accused products. Given these findings, the Court affirmed the district court’s grant of summary judgment of noninfringment.

Practice Note: This case serves as yet another reminder to those drafting and prosecuting patent applications to avoid, as much as possible, imperative language in the specification or in arguments. The Court used the same phrase from the specification (i.e., “leg member must flex”) to confine the scope of the asserted claims in both the literal infringement and doctrine of equivalents analyses.