Reversing a summary judgment of non-infringement based on a claim construction that excluded a disclosed embodiment, the U.S. Court of Appeals for the Federal Circuit, finding no disclaimer or estoppel during prosecution, vacated the district court claim construction and remanded the case. Oatey Co. v. IPS Corp., Case No. 07-1214 (Fed. Cir., Jan. 30, 2008) (Newman, J.).

The patented invention concerns washing machine outlet boxes to collect hoses for the input and output water flow of washing machines. Oatey’s patent is directed to an outlet box easily installed in a wall during building construction that accommodates two output drain ports and that has a “tailpiece” to collect the effluent from these ports and release it into a single drain pipe. Prior outlet boxes required that the installer perform several welds to join separate drain pipes from the drain ports into a single pipe below the outlet box.

As described in the preferred embodiments, the tailpiece may be integrally formed with the bottom wall or welded to the bottom wall of the box. In either event, the tailpiece contains two fluid passageways that feed into a drain pipe. The patent drawings also illustrate an alternate embodiment in which instead of two fluid passageways, two juxtaposed drain ports are separated only by a dividing wall. The Oatey claims recited “first and second juxtaposed drain ports” in the bottom wall.

The district court construed this clause to require “two separate identifiable physical elements that are adjacent or near each other,” thus excluding the alternate disclosed embodiment where a single opening was divided by a wall in the tailpiece. Oatey stipulated it could not meet its burden of proving infringement on this claim construction and appealed.

The Federal Circuit, after string citing a line of cases for the proposition that “[w]e normally do not interpret claim terms in a way that excludes embodiments disclosed in the specification,” went on to note that there was no “disclaimer or estoppel during prosecution, as would preclude recovery of such lost scope” and that the patent specification “explicitly” stated that the opening in the bottom wall of the box, in conjunction with the tailpiece, “may itself define the drain ports.” Thus, the Federal Circuit reversed, concluding that “where claims can reasonably be interpreted to include a specific embodiment, it is incorrect to construe the claims to exclude the embodiment, absent probative evidence on the contrary.”