Title: Method of making polytetrafluoroethylene sealing elements with hydrodynamic action

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 an outer cylindrical surface of the desired diameter and an inner cylindrical surface approximating but slightly smaller than 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. The flat washer is then first assembled with a metal case and then a desired hydrodynamic shape, such as a spiral groove, is coined in. Preferably, the inner pierce is completed at this time. Each washer may then be formed under pressure to permanently deform the radially inner portion thereof to a frustoconical shape. The assembled seal may be held on a shaft-size mandrel during application of a coating to the metal case.

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Inventors: Clark, William E. (Chelsea, MI, US)
Butler, John David (Van Wert, OH, US)

Application Number: 546882
Filing Date: 1975-02-04
Publication_date: 1976-02-24
Assignee: Federal-Mogul Corporation (Southfield, MI)
Primary Class(es): 29/417 29/511, 29/DIG34, 264/159, 264/163, 264/293, 264/296
Other Classes:
US Patent Ref:

1936804	Nov, 1933	Stein	29/DIG.
3004297	Oct, 1961	Stover	264/163.
3032825	May, 1962	Proud	264/159.
3137935	Jun, 1964	Gachot	29/450.
3207826	Sep, 1965	Yost	264/320.
3268984	Aug, 1966	Kupchick	277/184.
3549445	Dec, 1970	McMahon	29/445.
3857156	Dec, 1974	Clark	264/295.

Other Refs:
Primary Examiner: DiPalma, Victor A.
Assistant Examiner:
Attorney: Owen, Wickersham & Erickson