| 摘要 |
A method and apparatus for molding a product having internal threads includes a threaded mold core and a device for rotating the mold core about the axis of its threads and for axially withdrawing the core from the mold at a rate that is related to the rate of rotation, according to the pitch of the threads. This is accomplished by a cam, which is rotated in synchronism with the device that rotates the core, and a follower for displacing the core as the cam is rotated. The cam follower is fixed with respect to the mold. The cam and threaded core are positioned on a carrier, along with the device for rotating the core, such that rotation of the cam displaces the carrier away from the mold. The core is inserted into the mold, prior to the molding process, by displacing the carrier toward the mold without rotating the core. In one embodiment, the cam is rotated by a uni-directional motor such that resetting of the cam after the core is withdrawn is accomplished by forward indexing of the cam a small amount to a zero position.
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