Plastic article or earthenware shaping or treating: apparatus – Female mold and charger to supply fluent stock under... – With product ejector
Reexamination Certificate
1998-10-05
2001-03-27
Pyon, Harold (Department: 1722)
Plastic article or earthenware shaping or treating: apparatus
Female mold and charger to supply fluent stock under...
With product ejector
C264S334000, C425S139000, C425SDIG005
Reexamination Certificate
active
06206682
ABSTRACT:
BACKGROUND OF THE INVENTION
Parts are commonly molded by injecting a heated polymer or die casting metal through a sprue hole, along a gate, and into a cavity formed between a pair of plates. Then, the cover plate is lifted and the gate part is broken away by a first ejector pin. Finally, the molded part is ejected from the mold by one or more second ejector pins. The molding press or other equipment in which the mold lies, commonly has a single knock-out piston that moves up to raise the ejector pins. Thus, a mechanism is required which is moved by the knockout piston, to lift the ejector pins in sequence. The design of such mechanism can be complicated by the fact that the upper ends of the ejector pins may have different horizontal positions for molds used for different parts. Presently, rack and pinion mechanisms are used to move at least one of the ejector pins, but this results in complexity and parts that can be readily damaged. A molding assembly with a mechanism for lifting ejector pins in a predetermined sequence, where the ejector pins can have different horizontal positions, and which was of simple construction, would be of value.
SUMMARY OF THE INVENTION
In accordance with one embodiment of the present invention, a mold assembly is provided for use in a molding machine that includes a knockout piston that can be forcefully moved up, where the assembly is constructed to lift different ejector pins in a predetermined sequence, in a simple, versatile, and rugged construction. First and second ejector pins are mounted respectively on first and second ejectors that can each move vertically, with the second ejector lying below the first one. The second ejector has a hole, and a force member is moveable largely vertically within the hole, the force member having upper and lower ends and being taller than the hole. The lower end of the force member lies directly over the knockout piston while the upper end of the force member lies directly below the first ejector, so when the piston is initially raised, it moves up the force member to move up the first ejector and ejector pin without moving the second ejector. The hole that receives the force member is narrower than the knockout piston, so when the knockout piston reaches the bottom of the second ejector, it then lifts the second ejector to lift the second ejector pin. Since the ejector pins are both mounted on vertically moving ejectors, they can be readily supported at different horizontal positions on the corresponding ejectors.
The force member can be a cam pivotally mounted about a horizontal axis on the second ejector. The cam upper end can be further spaced from the axis than the cam lower end, so the first ejector is moved up more rapidly than the second one. The force member can be a simple shaft that moves vertically.
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ITT Manufacturing Enterprises Inc.
Luk Emmanuel
Pyon Harold
Turner Roger C.
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