One wrinkle of IPR practice is that patentees are often in the position of advocating a narrower claim scope than the challenger — just the opposite of what is usually seen in district court litigation. The narrowing strategy is logical — particularly where there is very close prior art, a patentee may need to seek a narrow construction in the IPR to avoid the prior art, and then worry about infringement later. However, the Federal Circuit decisions that restrict efforts by district court defendants to limit a claim to the preferred embodiment also functions to limit patentees in IPRs. The Federal Circuit’s November 9, 2016 decision in Schoeller-Bleckmann Oilfield Equipment AG v. Churchill Drilling Tools US, Inc. is a good example of that dynamic.
Schoeller was an appeal from the PTAB’s decision that the challenged claims were anticipated and obvious. The technology involved drilling apparatuses, and specifically a mechanism for allowing and restricting the flow of liquid through a drill string to activate and deactivate a downhole tool. The only issue on appeal was whether the Board properly construed “ball-like portion.” In the claim, that limitation was a part of a “deformable activator” that restricts fluid flow when engaged with a seat.
The issue presented was whether the Board properly construed the term as “a structure with at least one outer curve” (which would encompass a deformable ball), or whether the term was limited to the “deformable ring” shown in the patent’s figures (as advocated by the patentee).
The Federal Circuit affirmed the Board, finding the patentee’s narrowing effort was contrary to the Court’s repeated teaching that claim terms should not be limited to a preferred embodiment without a clear intent to redefine the term or a clear disavowal of claim scope, citing Thorner v. Sony as an example. Looking particularly to the patent, the Court determined the specification allowed a ball as a species of the “ball-like portion” based on a specification passage stating “the dart can pull the ball downwardly.” This case serves as a good reminder that a broad specification can actually hurt a patentee in an IPR.