Federal Circuit Reminder that “Comprising” is Open-Ended in Patent Claims

Construing patent a patent claim whose preamble recited an “electrical power distribution plugstrip comprising in combination” a variety of elements listed in the body of the claim, the Federal Circuit overturned a finding of infringement based on a construction that “the claimed invention was limited to a single, fully-integrated device.”  Server Technology, Inc. v. American Power Conversion Corp., No. 2015-1605 (Fed. Cir. Sept. 23, 2016).

Claim 15 of U.S. Patent No. 7,702,771 recites:

An electrical power distribution device connectable to one or more electrical loads in an electrical equipment rack, the electrical power distribution device comprising in combination:

an enclosure having a length that is longer than a width of the enclosure;

a power input penetrating the enclosure;

a plurality of power outputs disposed along an area on a face of said length of the enclosure, each among the plurality of power outputs being removably connectable to a corresponding one of said one or more electrical loads;

a plurality of power control relays disposed in the enclosure, each among said plurality of power control relays being connected to said power input and to one or more corresponding power outputs among said plurality of power outputs;

a digital current information display disposed on another area of the enclosure in current determining communication with at least one among said power input and said plurality of power outputs; and

a current information reporting system (i) associated with the enclosure (ii) in power information determining communication with at least one among said power input and said plurality of power outputs, and (iii) communicatingly connectable with a distal current information reporting system through a communications network external to the electrical power distribution device.

A key issue in this appeal was the district court’s construction of “the word ‘plugstrip’ in claim 15” as including “a one-piece limitation; the claimed invention was limited to a single, fully-integrated device.”  A jury verdict of infringement followed presentation by experts concerning the one-piece limitation, and the judge’s statements at trial that the patents-in-suit “had a one-piece limitation.”

The district court was incorrect to interpret “the term 'comprising' in claim 15 of the ’543 patent to require that all six elements must be contained inside a single enclosure.”  The Federal Circuit has “recognized that ‘comprising’ is a term of art that means “including but not limited to.” The use of “comprising” in claim 15 “only means that the plugstrip must have at least all six of the claimed elements, but not that all six elements must be contained in a single enclosure.”  A dependent claim called out the two-piece embodiment, and moreover, “the fact that the specification discloses a one-piece embodiment does not limit the plain language of claims that are broader than that disclosed embodiment.”  The court therefore reversed the court’s claim construction, and the jury’s finding of infringement.

This (non-precedential) Federal Circuit opinion, though arising from a claim construction in litigation, is a useful reminder against patent examiners’ attempts to limit claims in ways not mandated by the claim language.  A claimed device can comprise various elements without being limited to those elements, or to a particular arrangement of those elements.

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