Seikosha Co., Ltd.

Hiroshi Noritake

Yoshiaki Ikeda

Yoshio Tamura

Takeo Murayama

Satoru Yoshizawa

Hideo Onda

Kazuhiko Kogo

An injection molding machine includes a sub-mold hollow structure defining a plurality of sub-mold hollows which are formed in at least one of a fixed-side base plate and a movable-side base plate with a keyway being formed in the base plate in which the sub-mold hollow structure is formed. A changeable sub-mold is detachably mounted in each of the sub-mold hollows, and a comb-shaped fixing key is detachably engaged in the keyway and fixes the changeable sub-molds when the comb-like fixing key is inserted into the keyway.

Injection molding machine having exchangeable sub-molds

A lead screw for moving, for example, a printing head or a magnetic head. The screw is molded from plastics by a split mold comprising a plurality of longitudinally extending sections. It has on its outer peripheral surface a helical groove satisfying the following relationship: ##EQU1## where P: pitch of the groove;

Lead screw for moving a head

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Tokyo, Japan

Hiroshi Noritake