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US 4,709,757 AGranted
Method of injection molding and plastic part formed thereby
AssigneeJohnson Service Company
InventorTom C. Bly
Life of this patent
Estimating the term…
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AssigneeJohnson Service Company
InventorTom C. Bly
Estimating the term…
A process for forming a plastic part having a tubular portion that is continuous and without any flash/mismatch due to mold parting lines in which an injection mold is provided having a cavity formed with a cylindrical surface portion and a core member removably inserted endwise into the cylindrical portion. A molten plastic material is injected into the cavity so that it extends into the cylindrical portion and around the core member. The core member is then withdrawn in an axial direction from the cylindrical portion after the plastic material therein has solidified enough to retain its tubular shape but before it has completely cooled to thereby enable the plastic material to shrink radially inwardly away from the cylindrical surface. Thereafter, the molded tubular shape and the cylindrical mold surface are moved relative to each other in an axial direction so that they are moved away from each other and the tubular portion is withdrawn from the mold, with the tubular portion yielding or flexing to whatever extent is necessary in order to clear the mold.
The method of forming a plastic part having a tubular portion with a radially enlarged lip at the terminal end thereof comprising:
A plastic molded radiator part having a tubular portion for supporting a hose, said tubular portion being provided with a smooth external surface uninterrupted with any sharp protrusions that could extend into a hose on said tubular portion and having a radially enlarged external surface lip at the terminal end thereof and a reduced thickness wall portion at the terminal end.
Dependencies are inferred from the claim text.