• Fred Hadidi

Are all the claims for a patent titled “Reduced Opening Elastic Drawstring Bag” limited to a bag wit


Poly-America, L.P. v. API Industries, Inc.

2016-1200, Decided: October 14, 2016

Case Summary

Are all the claims for a patent titled “Reduced Opening Elastic Drawstring Bag” limited to a bag with a “reduced opening,” even if they do not explicitly recite the “reduced opening” feature? Yes, if the patent owner clearly and unambiguously disavows claims lacking that feature.

Plaintiff Poly-America asserted claim 10 of its US Patent 8,702,308 against an elastic drawstring garbage bag (without a reduced opening) manufactured by API Industries. This claim does not explicitly discuss the relative widths of the bag’s opening and body, but it does recite “short seals”—two structures at either side of the bag’s top opening that secure the elastic drawstrings.

Before trial, the district court construed the “short seal” limitation as “A seal for securing the elastic drawstring, which seal is located adjacent to a side seal [which secures the bag’s body panels], and that is not substantially aligned with the side seal, but extends inwardly from the interior edge of the side seal.” The court construed the claim this way because the patent owner identified a reduced bag opening (provided by the short seals) as “one of the characteristics of the invention,” and distinguished prior art drawstring garbage bags on the ground that they do not disclose reduced openings. Since API’s accused products are conventional drawstring garbage bags with short seals that do not extend inwardly, infringement was impossible under this construction.

On appeal, the patent owner argued that the district court could only construe the “short seal” limitation as it did by importing limitations from embodiments described in the specification, misreading the prosecution history and ignoring principles of claim differentiation. The Federal Circuit disagreed, ruling that Poly-America had disavowed drawstring bags with short seals that do not extend inwardly.

In its discussion of the ‘308 patent’s specification, the panel noted that every embodiment of the elastic drawstring bag has a “reduced opening” created by the inwardly extended short seals; that every section of the specification indicates the importance of inwardly extended short seals; that the patent identifies the use of inwardly extended short seals to create a reduced width opening as “one of the characteristics of the present invention;” that the specification identifies the extended short seals as an improvement upon prior art trash bags; and that the only depiction of a bag without the “reduced opening” feature is identified as prior art.

In its discussion of the ‘308 patent’s file history, the Court explained that Poly-America distinguished all of the patent’s claims on the basis that the prior art did not disclose the “reduced opening” feature. The panel concluded that these statements in the specification and prosecution history amounted to “a clear and unmistakable disavowal of short seals that do not extend inwardly.”

Finally, in dismissing Poly-America’s argument that claim differentiation principles preclude importing the “reduced opening” limitation into claim 10 (because other claims include that limitation), the panel said that “claim differentiation does not serve to broaden claims beyond their meaning in light of the patent as a whole, and it cannot override clear statements of claim scope found in the specification and prosecution history.”

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