Corresponding Structure in the Specification Does Not Render a Means-Plus-Function Term Structural
Before Reyna, Taranto, and Stoll. Appeal from the PTAB.
Toro petitioned for IPR of an MTD Products patent relating to lawnmowers. MTD argued the term “mechanical control assembly” was a means-plus-function term. The Board concluded the disputed phrase was primarily functional, but that a personal skilled in the art would have understood the term to denote structure based on the specification and prosecution history. Thus, the Board determined the term was not a means-plus-function term and held the challenged claims were obvious.
The Federal Circuit disagreed. Interpreting a means-plus-function limitation involves two steps. The first step is to determine whether the limitation is a means-plus-function limitation. If so, the second step is to look to the specification to identify structure that performs the claimed function(s). The Board correctly found the term was primarily functional, but erred in determining that corresponding structure in the specification meant the term was not a means-plus-function term. As the Federal Circuit explained, “this view would seem to leave § 112 ¶ 6 without any application: any means-plus-function limitation that met the statutory requirements . . . would end up not being a means-plus-function limitation at all.” While the specification and file history are relevant, they did nMot clearly disclaim that the claim limitation was a means-plus-function limitation. Thus, the Federal Circuit vacated and remanded for further consideration.
Editor: Paul Stewart