Osaka District Court, 1998 (Wa) 12899 — Electric Pipe Bending Apparatus
更新日：2 日前
Article information
Article type: Case note
Categories: Patents
Topics: Doctrine of equivalents, Claim interpretation
First published on this website: 2026-10-16
Display and classification checked: 2026-10-17
Case information: 1998 (Wa) 12899
Osaka District Court, 1998 (Wa) 12899 — Electric Pipe Bending Apparatus
* The defendant simultaneously sold an “electric straight-pipe bender,” a “bender shoe,” and a “bender guide.” Assembling the three infringed the patent.
⇒ Held to constitute direct infringement!!
* The estoppel objection under the fifth requirement was rejected, and equivalence was recognized.
Arguments that did not affect inventive step.
(Excerpt from the decision)
The portions of the plaintiff’s … statements in written opinions and other documents during prosecution of the patent application that concerned the pipe holder (…) asserted, in comparison with the publicly known technology cited in the notice of reasons for refusal or the decision of refusal, that the invention’s pipe-supporting parts were not at the starting point of bending but were distributed on both sides of it, avoiding undesirable lateral pressure from the outside of the bend. Apart from that, they merely described differences from the cited references in line with the wording of Claim 1 concerning the pipe-supporting member before the complete amendment at issue, and cannot be regarded as expressing an intention specifically to exclude other structures of pipe-supporting members. Moreover, through the complete amendment, the pipe-supporting member (pipe holder), originally described in the specification as “a pipe-supporting member having a straight-axis semicircular groove, connected to the matrix via a base plate and functioning as an auxiliary device freely rotatable about a pin mounted on the base plate so as to cooperate with the matrix and the auxiliary matrix during bending,” became “a pipe holder (…) provided on the outer peripheral portion of the rotary former, holding the pipe near the starting portion of bending, and keeping the pipe integral with the rotary former during rotation of the rotary former.” Accordingly, among the statements concerning the pipe-supporting member in the above written opinions and other documents, those relating to points changed by that amendment provide no basis for limiting the interpretation of the claims after amendment (…). The invention was patented as satisfying the patentability requirements notwithstanding the above changes concerning the pipe holder. The applicant’s statements about the pipe holder in written opinions and other documents during prosecution therefore cannot be regarded as a case in which the applicant made statements limiting the meaning of the claims in response to an examiner’s reasons for refusal or grounds of a patent opposition, those statements were accepted by an examiner or trial examiner, and a decision to grant a patent resulted.
Accordingly, the defendant’s argument for a restrictive interpretation under the doctrine of estoppel cannot be accepted.
Originally published: 2025-03-18
Original Japanese post: https://ameblo.jp/hideki-takaishi/entry-12890374936.html
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2026-10-16: The AMEBLO source was first published on this website.
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