Hakim v. Cannon Avent Group, PLC, et al.
Failure to retract arguments made during prosecution of the parent application resulted in a narrow construction of claim terms in the patent issued from the child application.
Hakim originally sued Avent in District Court (W.D. La.) asserting infringement of Hakim’s United States Patents No. 6,321,931 (the ‘931 patent) and No. 6,357,620 (the ‘620 patent) by Avent’s leak-resistant drinking cups. The district court granted Avent’s motions for summary judgment that the ‘931 patent is not infringed, based on the claim construction that limited the ‘931 claims to a sealing mechanism that includes a flexible valve material or diaphragm having a slit. On appeal, the CAFC affirmed.
The technology at issue relates to drinking cups that prevent the spilling of liquid if the cup is tipped over. Hakim’s patented cups have a valve through which fluid can pass when suction is applied by a person by way of a drinking spout, whereby the valve closes to seal the cup when a person is not drinking. Avent’s accused drinking cup has a valve with a flexible diaphragm having a central opening, but the opening is not a slit that opens and closes, but simply a hole in the diaphragm. The diaphragm rests against a plastic mount that has a conical head that seals the hole. Upon suction by a person seeking to drink, the diaphragm is lifted off the conical head, exposing the hole and permitting fluid to flow from the cup to the drinking spout.
During the initial prosecution of the ‘931 application, the presence of the slit in the flexible valve material was emphasized as distinguishing all of the claims from the cited references. The broader term “opening” was subsequently introduced to claims when Hakim filed a continuation application after receiving a notice of allowance for claims wherein the word “slit” appeared instead of “opening.” The continuation claims were allowed without any comment or rejection by the examiner.
In construing the claims of the continuation patent, the district court held Hakim to his arguments in the parent application that the invention included the presence of a slit in the flexible material. The district court stated: “Because Hakim did not retract any of his arguments distinguishing the prior art, he is held to the restrictive claim construction he argued during prosecution of the patent.” (Emphasis mine). Hakim argued, however, that he informed the Examiner that the new claims in the continuation were broader than those previously allowed, and that when the Examiner allowed the new claims without rejection, there is a presumption that the Examiner had assured himself of the patentability of the new claims. The CAFC disagreed.
Hakim had the right to refile the application and attempt to broaden the claims. However, an applicant cannot recapture claim scope that was surrendered or disclaimed. The district court did not err in holding that the examiner’s action in allowing the continuation claims without further prosecution was based on the prosecution argument in the parent. Although a disclaimer made during prosecution can be rescinded, permitting recapture of the disclaimed scope, the prosecution history must be sufficiently clear to inform the examiner that the previous disclaimer, and the prior art that it was made to avoid, may need to be re-visited.
Accordingly, the CAFC held that the district court correctly ruled that the word “opening” is properly construed to mean the sealing mechanism provided by the slitted diaphragm.