Claim Interpretation and Implicit Definitions in the Specification

Patents are powerful tools to help protect business interests. Often the key issues that affect business (validity and/or infringement) come down to claim interpretations. The patentee wants an interpretation broad enough to ensnare the accused device, but not so broad as to encompass the prior art. On the flip side, the accused infringer has too options - a narrow interpretation that enables it to avoid infringement, or a broad interpretation that encompasses the prior art. The tension between these is what pushes and pulls at the meaning of claims, enabled and amplified by the imprecision of language.

But finding the proper interpretation can be tricky, especially because claims terms should be interpreted in light of the specification. One overt way in which the specification impacts claim interpretation is when the specification explicitly defines a term. But the specification’s impact can be more nuanced, such as when the specification implicitly defines a term. As explained in the Phillips case (Phillips v. AWH Corp., 415 F.3d 1303, 1321 (Fed. Cir. 2004), this includes where the specification acts as a dictionary by defining a term by implication.

Examples of a definition by implication are subtle and easy to overlook. Today we see an example where neither the applicant nor the examiner realized the specification had such an implicit definition until it was pointed out by the PTAB in their decision reversing a rejection. The technology relates to baseball bats, and in particular to a cantilevered insert for an Easton bat (sn 16/803,557).

Claim 1 is provided below:

As a quick aside, I recently enjoyed some 80 MPH fun at the cages with my trusty 33/30 Easton (see the video below). My bat is old and definitely did not have this most recent innovation. Nevertheless it was great to still be able to make contact.

Returning to patent prosecution, the examiner interpreted the “spacer elements” forming the gap so broad as to read on prior art using an adhesive layer. In other words, according to the examiner, since the adhesive layer was spaced between the tube and the outer shell, it served as a spacer.

The Applicant obviously disagreed and asserted that the examiner’s interpretation was too broad, because the whole point of the spacers was to form a gap, and the cited art had no such gap.

The PTAB approached the issue by considering an alternative example in the specification that had only a single spacer, plus adhesive:

Paragraph [0047] is reproduced below as well:

Thus, the PTAB confirmed that the examiner’s interpretation was too broad because if bonding adhesive could serve as a spacer within the meaning of claim 1, then the FIG. 8 embodiment described in paragraph [0047] would have two spacers instead of just one whenever adhesive is used to bond the proximal end to the barrel segment. The fact that the applicant considered the FIG. 8 embodiment to have only one space (e.g., by omitting one or more space elements at the proximal end), by implication, defined the scope of “spacer” more narrowly than interpreted by the examiner.

While the Board here went out of its way to review the specification for consistency in the applicant’s use of claim terms, many applicants are not so fortunate. When there is an issue as to proper interpretation, every applicant must check their own specification for how the term is used (in all instances) and whether there are arguments for (or against) the examiner’s interpretation based on usage in the specification.