Open Claim Language Saves Patentee From Disclaimer

WeightMachineFree Motion Fitness v. Cybex (Fed. Cir. 2005).

Free Motion sued Cybex and Nautilus for infringement of its patents relating to pulley-based exercise machine. After construing the claims, the district court granted summary judgment of noninfringement to the defendants and also found that an amendment made to the claims during prosecution estopped Free Motion from asserting equivalence.

‘First’ pivot point: On appeal, the CAFC took issue with the district court’s interpretation of the term ‘first’ — finding in patent claims, the adjective ‘first’ generally does not suggest a location of the element.  Rather, terms such as ‘first’ and ‘second’ are used as labels to distinguish similar elements from one another.

‘Adjacent’: Construing the term ‘adjacent,’ the  CAFC resorted to a dictionary definition, but first “scrutinize[d] the intrinsic evidence in order to determine the most appropriate definition.” 

‘A cable’: Because the specification described the cable system as using a “single cable,” defendants argued that the claimed ‘a cable’ should be limited to a single cable rather than the usual ‘one or more cables.’  The CAFC rejected that argument, because there was not evidence of “a clear intent by the patentee to limit the article to the singular.”

Disclaimer: During prosecution, the patentee argued over a piece of prior art and included a statement that “the claimed assembly provides for virtually no variation in in cable tension [as disclosed in the prior art].” Defendants argued that, because their system did include the variation in cable tension, that Free Motion should be estopped from asserting infringement. 

The CAFC disagreed, holding that patent law does not allow a party to “avoid infringement of a patented claim using an open transitional phrase, such as comprising, by adding additional elements.”

The presence of an undesirable prior art feature in addition to the elements recited in the claim, even when the undesirability of that feature formed the basis of an amendment and argument overcoming a rejection during prosecution, does not limit the claim unless there is a clear and unmistakable disclaimer of claim scope. Here, there is no such disclaimer. The “comprising” language allows additional features. The disclaimer, if there was one, only applied to the “claimed assembly,” not unclaimed features added to the patented device.

Vacated and Remanded.

DISSENT: In dissent, Judge Prost dove into the intrinsic evidence and argued that it fully supported the lower court’s decision.


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