Print PDF

Statements in Parent Application Prosecution History Did Not Act as Disclaimers Where Claims Differed from Child Application

06-1576
June 27, 2007

Decision icon Decision

Last Month at the Federal Circuit - July 2007

Judges: Michel, Bryson (author), Dyk

[Appealed from: E.D. Va., Judge Brinkema]

In Saunders Group, Inc. v. Comfortrac, Inc., No. 06-1576 (Fed. Cir. June 27, 2007), the Federal Circuit reversed and remanded the district court’s grant of SJ of noninfringement. Specifically, the Federal Circuit held that the district court erred in construing the claims of U.S. Patent No. 6,899,690 (“the ’690 patent”) to require the presence of at least one pressure activated seal, a limitation that was not present in the accused devices.

The Saunders Group, Inc. (“Saunders”) competes with the defendants in the market for relatively inexpensive and lightweight cervical traction devices, the subject of the ’690 patent. Cervical traction is a physical therapy treatment in which a device is used to generate a sustained force pulling upward on the patient’s neck so as to relieve pressure on enflamed or enlarged nerves. Saunders filed an action against the defendants for infringement of the ’690 patent. The district court held that the term “pneumatic cylinder” in the asserted claim was limited to a pneumatic cylinder containing at least one pressure activated seal. At the same time, the district court granted SJ of noninfringement.

On appeal, the Federal Circuit held that the district court erred in narrowly construing the claim term “pneumatic cylinder” to require at least one pressure activated seal. The Court noted that it was not disputed that the ordinary meaning of “pneumatic cylinder” does not require the presence of pressure activated seals. The Court also found that nothing in the text of the ’690 patent and its prosecution history justified such a restrictive construction of the term.

Moreover, the Court explained that the strongest indication that the term “pneumatic cylinder,” as used in the ’690 patent, was not meant to include pressure activated seals as a matter of definition could be found in a comparison of independent claim 1 and claim 6, which depends from claim 1. The Court noted that claim 1 does not expressly require a “pressure activated seal,” whereas claim 6 adds a further limitation reciting a pressure activated seal. The Court concluded that the doctrine of claim differentiation supports the inference that claim 1 encompasses cylinders without pressure activated seals.

The Court also found that the prosecution history of the ’690 patent further supported the conclusion that the term “pneumatic cylinder” is not restricted to ones that use pressure activated seals. The parent application specifically required at least one pressure activated seal in all of its claims. When the patentees filed a continuation application, they omitted that limitation from some, but not all, of the new claims. The Court concluded that this was a strong indication that the claims not reciting pressure activated seals were not intended to require them.

The Court also concluded that the Petition to Make Special was significant because the applicants asserted in that document that the defendants’ device lacking a pressure activated seal infringed the independent claims of the application. Furthermore, although the specification did not describe any pneumatic cylinders without pressure activated seals, the Court nevertheless noted that a patent that only describes a single embodiment is not necessarily limited to that embodiment. Although the specification contained passages that described the traction device as comprising at least one pressure activated seal, the Court noted that those passagesdid not expressly statethat the pressure activated seal was an “essential component of the invention.” Slip op. at 9. The Court concluded that “[w]hile the restrictive language of the specification might be sufficient in other contexts to limit the scope of the claims, it is not sufficient in this case, where the language of the claims so clearly distinguishes between those claims that require the presence of a pressure activated seal and those that do not.” Id.

Nor was the Court persuaded by the defendants’ argument that the prosecution history of the parent application unambiguously disclaimed pneumatic cylinders lacking pressure activated seals. The Court noted that the claims in the parent application explicitly required at least one pressure activated seal, and the alleged disclaimer in the prosecution history distinguished the prior art focused on a particular claim limitation, the “pressure activated seal,” found in the claims of the parent application—and was not directed to the invention as a whole. The Court thus held that “[w]hen the purported disclaimers are directed to specific claim terms that have been omitted or materially altered in subsequent applications (rather than to the invention itself), those disclaimers do not apply.” Id. at 10. Moreover, the Court found that statements in the parent application prosecution history that argued that prior art pneumatic cylinders were unable to maintain the required traction force did not establish that the cylinder in the ’690 patent must contain a pressure activated seal.

Lastly, the Federal Circuit held that the district court erred in applying the maxim that claims should be construed to preserve their validity and also erred in concluding that if claims 1 and 16 were construed broadly, they would not be enabled because the specification only described a pneumatic cylinder having at least one pressure activated seal. The Federal Circuit explained that in light of the structure of the claims (with some reciting pressure activated seals and others lacking that information), the focus of the Petition to Make Special on the defendants’ device, and the absence of any clear disclaimer in the specification or prosecutionhistory, the claim term “pneumatic cylinder” unambiguously encompasses cylinders that do not use pressure activated seals. The Court noted that any validity issues that the defendants had preserved could be addressed on remand.