Method injection molded a plastic part with a round tubular portion
Patent 4873043 Issued on October 10, 1989. Estimated Expiration Date: 
March 25, 2008. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.
March 25, 2008. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.Patent ReferencesMethod of making and applying ethylene-propylene diene terpolymer texturized heat shrinkable tubing Method of injection molding and plastic part formed thereby Patent #: 4709757 InventorAssigneeApplicationNo. 173145 filed on 03/25/1988US Classes:264/237, Cooling264/328.1, Introducing material under pressure into a closed mold cavity (e.g., injection molding, etc.)264/336Ejecting or stripping before full set or cure of workExaminersPrimary: Silbaugh, Jan H.Assistant: Heitbrink, Jill L. Attorney, Agent or FirmInternational ClassB29C 045/40AbstractA process for forming a plastic part having a tubular portion that is continuous and without an 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 The core member is then withdrawn in an axial direction from the cylindrical portion after the plastic material therein has solidified enough to retain its tubular shape but before it has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 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relative to each other in an axial direction so that they are moved away from each other and the tubular portion is withdrawn from the mold, with the tubular portion yielding or flexing to whatever extent is necessary in order to clear the mold.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 inner surface of the tubular portion is formed with a symmetrical discontinuous inner surface to insure even shrinking of the tubular portion during cooling and thereby insure roundness of the tubular portion of the molded part.Field of SearchCoolingCompleting vulcanization or polymerization UTILIZING HEAT RELEASABLE STRESS TO RESHAPE SOLID WORKPIECE (E.G., ELASTIC MEMORY, ETC.) Introducing material under pressure into a closed mold cavity (e.g., injection molding, etc.) Article or material ejecting, core or mold stripping or separating Ejecting or stripping before full set or cure of work To shrink To complete vulcanization or polymerization To cool | |
