On Monday, August 12, the Federal Circuit issued a precedential opinion on means-plus-function claims. The opinion serves as an important reminder to practitioners that generic claim terms lacking sufficiently definite structure may be subject to §112, ¶6 or §112(f).A copy of the Federal Circuit’s opinion can be found here.
In the opinion, the Federal Circuit vacated a decision by the Patent Trial and Appeal Board that found a patent owned by Calfee client MTD Products Inc was invalid. Calfee’s attorneys argued that the claims of MTD’s patent were patentable because a term recited in the claims of the patent – “mechanical control assembly”– was a means-plus-function term. The Court agreed with MTD that the term is a means-plus-function term subject to 35 U.S.C. §112, ¶6 and remanded the case back to the Board for further proceedings. The Court found that the Board erred by conflating corresponding structure in the specification with a structural definition of the
term, and by misinterpreting certain statements in the prosecution history. John Cipolla, Tracy Johnson, Mark McDougall, and Andrew Alexander from Calfee’s Intellectual Property group represented MTD in the case. John Cipolla argued MTD’s case to the Federal Circuit. Read more about the decision here.
The Federal Circuit explained that a generic, nonce term will not connote definite structure merely because it is used in the specification to describe structure unless the patentee acted as its own lexicographer to define the term. Although the Board correctly found that “mechanical control assembly” is a nonce term, it erred when it then relied on the patent’s specification to conclude that the term had an established structural meaning. The specification did not expressly define “mechanical control assembly,” and the Court reasoned that just because the specification discloses a structure corresponding to the “mechanical control assembly”
does not mean that the term is understood to connote a specific structure or class of structures.
The Federal Circuit also noted that the prosecution history will not exclude a finding of a means-plus-function term unless there is a clear and undisputed statement foreclosing application of §112, ¶6 or §112(f). The Court here found that statements made by MTD during prosecution of the patent did not clearly disclaim a means-plus-function interpretation of “mechanical control assembly.” The statements were not in the means-plus-function context and were not inconsistent with means-plus-function claiming.
Calfee’s Intellectual Property attorneys understand that claim construction is critically important in all areas of patent practice. With one of the largest IP practices in a general practice firm within the Midwest, we have broad experience and a deep bench in patent prosecution, litigation, opinions and counseling. If you have any questions about how this decision impacts your business and patent needs, please feel free to contact us.