“Spreader for osteotomy”


In the prior instance, the Tokyo District Court found that the patent in question was infringed under the doctrine of equivalents. The case was appealed to the Intellectual Property High Court (IP High Court) which affirmed the prior instance judgment, on the grounds of literal infringement.

Legal Issue:

The case concerned whether the defendant’s product includes the claimed feature of “one pair of … swinging members is provided with engaging parts” (feature E)

Summary of Conclusions:

Feature E is directed to “a spreader for osteotomy, wherein one pair of said two pairs of swinging members is provided with engaging parts which are to be engaged with the other pair of swinging members when assembled with the other pair of the swinging members.” The court interpreted “one pair of … swinging members is provided with engaging parts” to mean that the “engaging parts” are provided to the swinging members and to require that it can be distinguished which of the two pairs of swinging parts the engaging parts are provided to, and further asserted that it is sufficient if such distinction can be made. The court went on to assert that as long as the “engaging parts” are”provided” to one pair of swinging members, seeing the entire swinging members including the “engaging parts,” the “engaging parts” can be said as a part thereof, and this does not exclude that the engaging parts be constituted by an additional member.

The Defendant’s product was described as including swinging members 1 and 2, an attachment and an angle adjustment unit. The court found that, before an opening operation, a protrusion of the attachment is fitted into an opening of swinging members 1 and 2 which are assembled, and that two pins of the angle adjustment unit are inserted into pin holes to fix the swinging members to one another. In view of such fixation aspect, the pin of the angle adjustment unit and the protrusion of the attachment which correspond to “engaging parts” can be said as being provided to the swinging members 1 and 2.

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This decision concerns an appeal made to a prior decision which has drawn attention for its finding of infringement under the doctrine of equivalents, with regard to a feature which was added into the claim in an amendment during the examination stage. The IP High Court’s decision in the matter was awaited with anticipation in view of its previous judgments asserting that when an amendment is made to restrict the scope of the claims during patent prosecution, the patent holder is no longer permitted to assert equivalence about the restricted feature (Case No. 2015 (Ne) 10127 – “Web-Pos method”; and Case No. 2016 (Ne) 10007 – “Chair with vibration function”). However, the IP High Court did not discuss the issue of equivalence in the present decision.