"Cutter Head" Not Means Plus Function Limitation

In Carl Landers, et al. v. Sideways, LLC (Fed. Cir, July 27, 2005, nonprecedential), the Federal Circut concluded that district court improperly construed the term "cutter head" as a means-plus-function limitation in claim 33 of U.S. Patent No. 6,125,949 (below):

33. An apparatus for use with upset tubing having a lower end in a well casing
to cut a hole in the wall of the casing and a lateral channel extending
outwardly from the casing, the apparatus comprising:

an elbow to be mounted on the upset tubing at its lower end to be lowered
into the well casing, said elbow providing an inlet and outlet with a passageway
therebetween, said inlet opening upwardly in the upset tubing and said outlet
opening outwardly toward the wall of the casing;

a motor, a flexible shaft and a cutter head, said flexible shaft extending
between the motor and the cutter head to provide a rotary drive connection, said
flexible shaft and cutter head being movable through the passageway to have the
cutter head engage the well casing adjacent the outlet to cut a hole in the
casing; and,

a cutting nozzle and hose configured to be lowered into the elbow
passageway to exit the outlet and cut the lateral channel outwardly from the
hole by fluid pressure from the nozzle.

Accourding to the appellate court, claim 33 contains several limitations providing structure to the cutter head, e.g., the cutter head must rotate, it is connected at one end to a “flexible shaft,” and it must be moveable through the “inlet” and “outlet” of an L-shaped “passageway.” Furthermore, the district court’s construction, which limited “cutter head” to a ball cutter and its equivalents, was erroneous under the doctrine of claim differentiation with respect to dependent claim 34 which limited the “cutter head” to “a ball cutter.”

To support the district court’s interpretation of the term “cutter head” as
a means-plus-function limitation, Sideways argues that the term should not be
given its ordinary meaning. According to Sideways, the patentee experimented
unsuccessfully with many different types of cutter heads and succeeded only with
a ball cutter. This argument, however, misses the point. The relevant inquiry is
how a person of ordinary skill in the art would have understood the simple term
“cutter head,” not whether other cutter heads succeeded or failed in cutting
well casings. Moreover, we note that the patent specification does not indicate
that only a ball cutter is capable of making a hole in a well casing.

We also reject Sideways’ contention that the term “cutter head” was properly
construed as a means-plus-function limitation because it lacks sufficiently
definite structure. Specifically, Sideways argues that the patent specification
and claims do not provide any structural detail concerning the cutter head. The
law does not require, however, that the specification and claims contain
exacting details of every structure recited in the claims. As we explained
above, the relevant inquiry focuses on whether a person of ordinary skill in the
art would have understood the limitation “cutter head” to have a sufficiently
definite structure.

Unless the intrinsic evidence compels a contrary result, a claim limitation should be given its ordinary and customary meaning. Phillips, slip op. at 9. We note that Landers, in its appellate briefing, has provided a good starting point for this task on remand by providing examples of “cutter heads” in the prior art. Appellants’ Opening Br., at 23-25. Accordingly, we vacate the district court’s finding of noninfringement of the ’949 patent, to the extent that that finding was based on an erroneous claim construction of the term “cutter head.” Furthermore, we remand for the court to give the term “cutter head” its ordinary and customary meaning, and
redetermine whether Sideways’ device meets that limitation.