Claims
- 1. In an apparatus for molding an article which includes a pair of mold members having recesses in their opposed surfaces which are adapted to mate to form a mold cavity, a pneumatic cylinder having a piston rod secured to one of the mold members for moving the mold members together to a collapsed position in which the mold cavity is of a volume less than the desired volume of the article being molded, a pipe connecting the pneumatic cylinder to a source of air under pressure, valve means connected to said pipe for allowing air to pass from the source to the pneumatic cylinder but preventing air to pass from the pneumatic cylinder to the source, and means for injecting a plastic mold material into the mold cavity when it is in its collapsed position to fill the cavity and force the mold members apart until they are in an expanded position in which the mold cavity is of the desired volume of the article, the improvement comprising
- an enclosed air reservoir connected to the pipe between the pneumatic cylinder and the valve means into which the air from the cylinder flows when the mold material moves the mold members to their expanded position for maintaining a substantially uniform pressure on the plastic mold material in the mold cavity when the material is moving the mold members from their collapsed position to their expanded position.
- 2. Apparatus in accordance with claim 1 in which the volume of the air reservoir with respect to the volume of the hydraulic cylinder is such as to provide a pressure of no greater than 30 psi on the mold material.
Parent Case Info
This is a division of application Ser. No. 350,087, filed Feb. 18, 1982, now U.S. Pat. No. 4,414,167, issued Nov. 8, 1983.
US Referenced Citations (8)
Divisions (1)
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Number |
Date |
Country |
Parent |
350087 |
Feb 1982 |
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