Kokan Kako Co., Ltd.

Takanosuke Ohki

A pipe material is tightly clamped into a first pair of split forming dies to form a first formed tubular body which comprises a cylindrical wall part and a flat wall part, and then the first formed body is clamped tightly into a second pair of split forming dies, the interior of which is formed to be complementary to a toothed rack to be produced on the flat wall part. A mandrel is then forcefully inserted, either with or without vibration, into the bore of the first formed part while contained within the second forming dies, so that the teeth of a rack are formed on the flat wall of the first formed part by plastic deformation. A rack thus produced from a pipe material is light in weight and inexpensive, while functionally equivalent to a rack conventionally produced by machining from a round bar.

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Yokohama, Japan

Takanosuke Ohki