Prosecution Disclaimer Narrows Claim Term In Continuation Patent

Hakim v. Cannon Avent Group, PLC, et al. (05-1398) - February 23, 2007

Hakim's patents covered drinking cups that prevent the spilling of liquid if the cup is tipped over. During patent prosecution, Hakim described his distinctions from the cited references by emphasizing that the flexible valve material in his mechanism had a "slit."

Hakim filed a continuation, where the word "opening" replaced "slit." The filing of the continuation was accompanied by an attorney letter stating that Hakim was broadening the claims on this basis.

The defendant's 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.

In construing the claims of the continuation patent, the district court held Hakim to his arguments in the parent application that the invention includes the presence of a slit in the flexible material. The 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." It was stressed that when Hakim wrote to the examiner that he was broadening the claims, he did not specifically point out that he no longer intended to be limited to the specific mechanism that he had previously argued was the distinguishing feature of his invention.

The CAFC affirmed:

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 Although a disclaimer made during prosecution can be rescinded, permitting recapture of the disclaimed scope, the prosecution history must be sufficiently clear to inform the examiner that the previous disclaimer, and the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.