Consider a Prosecution
History Disclaimer for Every
Michael V. Messinger & Jon E. Wright
Consider a Prosecution History Disclaimer
for Every Continuation Application
Michael V. Messinger and Jon E. Wright
Patent owners and practitioners should consider modifying their continuation practice in
light of a recent case from the Federal Circuit. In Hakim v. Canon Avent Group, the court
appeared to lay down strict requirements for practitioners using continuation applications to
broaden unnecessarily narrow claims and clarify unnecessary estoppels created during
prosecution of parent applications. In Hakim, the court relied on statements made during
prosecution of a parent application to narrowly construe a claim term that was explicitly
broadened in the child application. The court ruled that the applicant's efforts to disclaim the
perceived estoppel were insufficient.
In a case involving "sippy-cup" valves, patent owner Hakim argued around asserted prior
art references by pointing to two separate mechanisms used to prevent leakage. The first
mechanism was a flexible valve material having a "slit" therein that responds to suction. The
second mechanism was a "blocking element" against which the "slit" rested when in a relaxed
position. Hakim stated that "[n]one of the references cited in the Office Action
suggest such a no-spill mechanism having a slit sitting against a blocking element such as recited
in all of the pending claims." The Examiner allowed the pending claims.
Believing that the term "slit" was too narrow, Hakim filed a continued prosecution
application, or a CPA. The CPA was accompanied by an attorney letter stating that Hakim was
broadening claims 1 and 2, and an amendment changing "slit" to "opening." The continuation
claims were allowed with no further comment or rejection by the examiner, and issued in U.S.
Patent No. 6,321,931 ("the '931 patent").
Hakim sued Cannon Avent Group ("Avent") alleging that its sippy-cup