PTAB decision vacated for not identifying "means plus function" claim

The outcome in MTD Products:


The Toro Company sought inter partes review of
claims 1–16 of U.S. Patent No. 8,011,458 before the U.S.
Patent and Trademark Office’s Patent Trial and Appeal
Board. The Board instituted review and, in its final written decision,
held the challenged claims obvious under
35 U.S.C. § 103. Critical to its decision, the Board determined that
the claim term “mechanical control assembly . . . configured to” perform certain functions is not a
means-plus-function term subject to 35 U.S.C. § 112, ¶ 6.
MTD Products Inc., owner of the ’458 patent, appeals the
Board’s decision.

We conclude that the Board erred by conflating corresponding structure
in the specification with a structural
definition for the term, and by misinterpreting certain
statements in the prosecution history. Under the appropriate legal framework,
we conclude that the term “mechanical control assembly” is a means-plus-function term
governed by § 112, ¶ 6. We therefore vacate the Board’s
obviousness conclusion, which was predicated on its incorrect claim construction,
and remand for further proceedings consistent with this opinion. Because we are
persuaded by MTD’s primary argument, we do not reach
its alternative arguments.



Of the Board's error:


We conclude that the Board erred, however, when it relied on the specification’s
description of a “ZTR control assembly” to conclude that the claim term “mechanical
control assembly” has an established structural meaning.
While the parties agreed that the ZTR control assembly in
the specification is the structure “corresponding to” the
claimed mechanical control assembly, MTD did not agree
that the specification expressly defines the claim term “mechanical control assembly.”
That the specification discloses
a structure corresponding to an asserted means-plus-function claim term
does not necessarily mean that the claim
term is understood by persons of ordinary skill in the art to
connote a specific structure or a class of structures.

(...)

Interpretation of an asserted means-plus-function limitation involves two steps.
First, we determine if the claim
limitation is drafted in means-plus-function format. As
part of this step, we consider whether the claim limitation
connotes “sufficiently definite structure” to a person of ordinary skill in the art.
If we conclude that the limitation is
in means-plus-function format, the second step requires us
to review the specification to identify the structure that
performs the claimed function(s) and thus “corresponds to”
the claimed means. While related, these two inquiries are
distinct. In this case, however, the Board conflated these
distinct inquiries, holding that the specification’s disclosure of corresponding
structure demonstrates that the alleged means-plus-function term is sufficiently definite so
as to not invoke § 112, ¶ 6. The Board’s analysis implies
that so long as a claim term has corresponding structure in
the specification, it is not a means-plus-function limitation.
This is not consistent with our prior decisions. Indeed, this
view would seem to leave § 112, ¶ 6 without any application: any means-plus-function limitation that met the
statutory requirements, i.e., which includes having corresponding structure in the specification, would end up not
being a means-plus-function limitation at all.
While we agree with the Board that the specification
plays a role in assessing whether particular claim language
invokes § 112, ¶ 6, we do not agree that the patent specification at issue here renders the nonce term “mechanical
control assembly” sufficiently structural to a person of ordinary skill in the art.