Disc base board molding die including stamper plate attaching/detaching device

Abstract

To injection-mold a base board for an optical disc or the like, an injection molding die includes a stamper plate attaching/detaching device installed therein. The stamper attaching/detaching device includes as essential components a stamper plate attaching/detaching bush adapted to be fitted into a tapered bush fitting hole formed in a die half on the movable side together with a stamper plate to be firmly placed on a die cavity, an actuating rod having a pinion gear formed at the fore end part thereof to mesh with a rack formed at the lower end part of the stamper plate attaching/detaching bush, and a lock nut for immovably hold the actuating rod during a series of molding operations. The stamper plate is removably fitted around the outer periphery of a flange portion of the stamper plate attaching/detaching bush. As the actuating rod is rotated by actuating a knob with an operator's hand, the stamper plate attaching/detaching bush is quickly linearly displaced in the die half on the movable side in the upward/downward direction via meshing engagement of the pinion gear of the actuating rod with the rack of the stamper plate attaching/detaching bush. To linearly displace the stamper plate attaching/detaching bush in the upward/downward direction, a pair of actuating rods each extending in parallel with each other may be arranged in the symmetrical relationship relative to the center axis of the stamper plate attaching/detaching bush.

Dependencies are inferred from the claim text.