In Poly-America, L.P. v. API Industries, Inc., Appeal No. 2016-1200, the Federal Circuit affirmed a narrow claim construction based on a “clear and unequivocal” disavowal of claim scope in the specification and prosecution history.
Poly-America sued API for infringing its drawstring trash bag patent. The entry of judgment turned, in part, on the construction of the term “short seal.” The accused device had short seals that did not extend inwards. The patent claim did not specify whether the short seals of the bag extended inwards. The district court construed the term to require inward extending seals based on the specification and prosecution history. The district court entered judgment in favor of API.
The Federal Circuit affirmed, explaining that the inventor clearly, unequivocally, and intentionally limited the claimed invention to inwardly extending short seals. Every embodiment described in the specification had the limitation. Additionally, every section of the specification indicated the importance of inwardly extending short seals. The Federal Circuit reasoned that those two facts together justified the district court’s construal of “short seal.” The Federal Circuit additionally reasoned that the district court’s claim construction was strengthened by Poly-America’s disavowed non-inwardly extending short seals in the prosecution history of the patent.