The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Oct. 12, 1976
Filed:
Sep. 18, 1975
William E Clark, Chelsea, MI (US);
Federal-Mogul Corporation, Southfield, MI (US);
Abstract
A method for manufacturing an oil seal element from polytetrafluoroethylene and the like. A tubular billet of polytetrafluoroethylene or the like is provided with inner and outer cylindrical surfaces approximating the desired diameter, and an end wall is faced off perpendicular to the cylindrical surfaces. A series of washers of a desired thickness is then sliced from the billet. In one form of the invention, each washer may next be cut to exactly the desired inner and outer diameter, and, simultaneously, spiral grooves or other hydrodynamic shapes may be formed on one face of each washer, leading from the inner periphery of each washer for a desired distance toward the outer periphery; this may be done by using a novel blank-pierce-coining die that both trims the seal and coins the groove between a pair of metal surfaces at very heavy pressure to permanently deform the material in these surfaces. Each washer is formed under pressure to permanently deform the radially inner portion thereof to a frustoconical shape, this operation preferably being carried on during assembly of the seal. The assembled seal may be held on a shaft-size mandrel during application of a coating to the metal case.