Stumbo v. Eastman Outdoors, Inc.

Steve Stumbo (plaintiff) held a patent for a portable, collapsible blind, or shelter, for use by hunters and outdoor enthusiasts. Each of the patent’s claims described the claimed invention as having a “closable vertical opening” along a corner for ingress and egress. Eastman Outdoors, Inc., and Ameristep Corporation (collectively, Eastman) (defendants) also manufactured portable, collapsible blinds. For ingress and egress, their products offered a zippered triangular opening on the blinds’ side wall. When Stumbo sued Eastman for patent infringement, Eastman argued that there was no direct infringement because the triangular openings were not the same as Stumbo’s vertical-slit openings. Eastman also argued that there was no infringement under a doctrine-of-equivalents theory because the triangular openings did not operate in substantially the same way to create substantially the same result as Stumbo’s vertical-slit openings. Stumbo argued that the phrase “closable vertical opening” described only the orientation of the opening as being vertical as opposed to horizontal. He therefore claimed that vertical openings in many shapes, including triangles, could support a direct-infringement claim. The district court concluded that the phrase “closable vertical opening” was properly construed to mean a slit-like opening running straight up and down. The court therefore granted summary judgment in Eastman’s favor, finding neither direct infringement nor infringement under the doctrine of equivalents. Stumbo appealed.