Apparatus for making polytetrafluoroethylene sealing elements with hydrodynamic action
US3985487A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Sep 18, 1975 |
| Grant date | Oct 12, 1976 |
| Priority date | — |
| Expiry date | Sep 18, 1995 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S425/047
- WIPO fieldOther special machines
- WIPO sectorMechanical engineering
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 met…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.