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US 4,214,507 AGranted
One-piece plastic piston
OwnerJules M. Hock, Donald S. de Vries, Jr.inventors
Life of this patent
Estimating the term…
Abstract
A piston comprising a core molded from a rigid thermoplastic material and a seal element molded on the core from a flexible thermoplastic material to form a unitary assembly.
Claims9
A unitary piston comprising:
- a core molded from a rigid thermoplastic material, said core consisting of a disc-shaped member having opposite sides and a radially extending flange at the perimeter thereof spaced axially inwardly from said sides, said flange having a plurality of holes extending therethrough;
- and
- a seal element made from a flexible thermoplastic material molded on said core, on at least opposite sides of said flange and on said perimeter, the material of said seal element extending through said holes in said flange to connect the material on said opposite sides to form a mechanical bond between said seal element and said core,
- there being no adhesion or chemical bond between said core and said seal element, said mechanical bond being the only means for holding said seal element on said core.
1 more element
A method of making a piston comprising the steps of:
- molding a core element from a rigid thermoplastic material, said core element consisting of a disc-shaped member having opposite sides and a radially extending flange at the perimeter thereof spaced axially inwardly from said sides, said flange having a plurality of holes extending therethrough;
- placing said core element in a mold without any adhesive or chemical bonding material on said core element;
- molding a seal element from a flexible thermoplastic material on said core element, on at least opposite sides of said flange and on said perimeter, the material of said seal element extending through said holes in said flange to connect the material on said opposite sides to form a mechanical bond between said seal element and said core element;
- and
- cooling said mold to prevent adhesion or chemical bonding of said seal element on said core element whereby said mechanical bond is the only means for holding said seal element on said core element.
2 more elements
Dependencies are inferred from the claim text.