US3929341A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of making polytetrafluoroethylene sealing elements with hydrodynamic action
Assignee: Federal Mogul LLC
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Filing: 1974-11-13
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Granted: 1975-12-30
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Expires: 1994-11-13
Abstract
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.
Inventors
- 👤 William E Clark
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 08:45
CPC Classifications
F; F16; F16J; F16J15/00; F16J15/16; F16J15/32; F16J15/3244; B; B29; B29D; B29D99/00; B29D99/0053; F16J15/328; B29C; B29C2793/00; B29K; B29K2027/00; B29K2027/12; B29K2027/18; B29L; B29L2031/00; B29L2031/26; Y; Y10; Y10T; Y10T29/00; Y10T29/49; Y10T29/49636; Y10T29/49702; Y10T29/49789; Y10T29/49798; Y10T29/49826; Y10T29/49908; Y10T29/49915; Y10T29/49917; Y10T29/49918
Claims Analysis
Total Claims: 22
Claim 1
Independent Claim
127 words
A METHOD FOR MANUFACTURING AN OIL SEAL HAVING AN ELEMENT MADE FROM A TUBULAR BILLET OF POLYTETRAFLUOROETHYLENE OR THE LIKE HAVING AN OUTER CYLINDRICAL SURFACE, A CONCENTRIC INNER CYLINDERICAL SURFACE, AND AN ANNULAR BODY BETWEEN SAID CYLINDRICAL SURFACES, COMPRISING THE STEPS OF: FACING OFF ONE END WALL PERPENDICULAR TO SAID CYLINDRICAL SURFACES, SLICING SAID BILLET AT A DESIRED THIN DISTANCE FROM SAID FACED END WALL TO PROVIDE A WASHER AND TO PROVIDE A NEWLY FACED END WALL WHICH IS THEREAFTER SLICED, PROCEEDING THUSLY THROUGH SAID BILLET TO PROVIDE A PLURALITY OF SAID WASHERS, AND COINING ONE FACE OF EACH OF SAID WASHER TO PROVIDE HYDRODYNAMIC MEANS FOR RETURNING OIL, LEADING FROM THE INTERSECTION OF SAID WALL WITH ITS INNER CYLINDRICAL SURFACE AND EXTENDING FOR A DESIRED WIDTH.
Claim 2
Independent Claim
127 words
A METHOD FOR MANUFACTURING AN OIL SEAL HAVING AN ELEMENT MADE FROM A TUBULAR BILLET OF POLYTETRAFLUOROETHYLENE OR THE LIKE HAVING AN OUTER CYLINDRICAL SURFACE, A CONCENTRIC INNER CYLINDERICAL SURFACE, AND AN ANNULAR BODY BETWEEN SAID CYLINDRICAL SURFACES, COMPRISING THE STEPS OF: FACING OFF ONE END WALL PERPENDICULAR TO SAID CYLINDRICAL SURFACES, SLICING SAID BILLET AT A DESIRED THIN DISTANCE FROM SAID FACED END WALL TO PROVIDE A WASHER AND TO PROVIDE A NEWLY FACED END WALL WHICH IS THEREAFTER SLICED, PROCEEDING THUSLY THROUGH SAID BILLET TO PROVIDE A PLURALITY OF SAID WASHERS, AND COINING ONE FACE OF EACH OF SAID WASHER TO PROVIDE HYDRODYNAMIC MEANS FOR RETURNING OIL, LEADING FROM THE INTERSECTION OF SAID WALL WITH ITS INNER CYLINDRICAL SURFACE AND EXTENDING FOR A DESIRED WIDTH.
Claim 3
Dependent Claim
36 words
The method of claim 1 having the additional step of forming each said washer under pressure to permanently deform the radially inner portion thereof to a frustoconical shape, leaving an outer annular rim that is planar.
Claim 4
Dependent Claim
80 words
The method of claim 2 having the additional steps of assembling the seal into a case, mounting the assembled seal on a cylindrical mandrel of substantially the same size as the shaft with which the seal is to be used, and then coating an outer peripheral portion of the case with a material to improve bore sealing, said coating being done at an elevated temperature, the supporting of the seal on the mandrel maintaining the frustoconical shape of the washer.
Claim 5
Dependent Claim
75 words
The method of claim 3 wherein after the step of forming said frustoconical shape, the assembled seal is mounted on a cylindrical mandrel larger in diameter than the inner diameter of said seal, and while supported thereon, coating an outer peripheral wall of said outer case with a solvent-carried material, said coating being done at an elevated temperature, said supporting of said seal on said mandrel preventing relaxation of said frustoconical shape by the heat.
Claim 6
Dependent Claim
28 words
The method of claim 1 wherein before said slicing step, the outer periphery of said billet is made to the final peripheral size given to each said washer.
Claim 7
Dependent Claim
34 words
The method of claim 1 wherein after said slicing step and before said coining step there is a step of trimming the inner and outer peripheries of each said washer to a desired size.
Claim 8
Dependent Claim
15 words
The method of claim 6 in which said coining and trimming steps are performed simultaneously.
Claim 9
Dependent Claim
20 words
The method of claim 1 wherein said forming step is done while simultaneously assembling said element into a seal case.
Claim 10
Dependent Claim
17 words
The method of claim 1 wherein said coining step comprises coining a spiral groove in said washer.
Claim 11
Dependent Claim
9 words
The product resulting from the method of claim 1.
Claim 12
Independent Claim
136 words
A method for manufacturing an oil seal element from a tubular billet of polytetrafluoroethylene or the like having inner and outer cylindrical surfaces and an annular body between said cylindrical surfaces, comprising the steps of: facing off one end wall perpendicular to said cylindrical surfaces, slicing said billet at a desired thin distance from said faced end wall to provide a wafer and to provide a newly faced end wall which is thereafter sliced, proceeding thusly through said billet to provide a plurality of said wafers, substantially simultaneously blanking and piercing each said wafer to provide inner and outer peripheries of desired diameters, and coining one face of each said wafer to provide hydrodynamic means for returning leaked fluid, leading from the intersection of said wall with its inner periphery and extending for a desired width.
Claim 13
Independent Claim
136 words
A method for manufacturing an oil seal element from a tubular billet of polytetrafluoroethylene or the like having inner and outer cylindrical surfaces and an annular body between said cylindrical surfaces, comprising the steps of: facing off one end wall perpendicular to said cylindrical surfaces, slicing said billet at a desired thin distance from said faced end wall to provide a wafer and to provide a newly faced end wall which is thereafter sliced, proceeding thusly through said billet to provide a plurality of said wafers, substantially simultaneously blanking and piercing each said wafer to provide inner and outer peripheries of desired diameters, and coining one face of each said wafer to provide hydrodynamic means for returning leaked fluid, leading from the intersection of said wall with its inner periphery and extending for a desired width.
Claim 14
Dependent Claim
17 words
The method of claim 11 wherein said coining is done substantially simultaneously with said blanking and piercing.
Claim 15
Dependent Claim
54 words
The method of claim 11 having the additional step of forming each said wafer under pressure to permanently deform the radially inner portion thereof to a frustoconical shape, leaving an outer annular rim that is planar, while sandwiching said outer annular rim between two metal case members and while locking said case members together.
Claim 16
Dependent Claim
48 words
The method of claim 11 wherein said blanking, piercing, and coining are done by gripping both faces of said wafer and flattening them between two members, blanking and piercing it while continuing to grip it, and then coining it with the same two members that were gripping it.
Claim 17
Dependent Claim
26 words
The method of claim 11 wherein said coining is followed by releasing the gripping while holding said wafer by one coining member away from other members.
Claim 18
Dependent Claim
9 words
The product resulting from the method of claim 11.
Claim 19
Independent Claim
64 words
A METHOD FOR MANUFACTURING AN HYDRODYNAMIC OIL SEAL ELEMENT FROM A GENERALLY FLAT WAFTER OF POLYTETRAFLUOROETHYLENE OR THE LIKE, COMPRISING THE STEPS OF: SUBSTANTIALLY SIMULTANEOUSLY BLANKING AND PIERCING SAID WAFTER TO PROVIDE THE DESIRED INNER AND OUTER DIMENSIONS, AND COINING ONE FACE OF SAID WAFER TO PROVIDE HYDRODYNAMIC MEANS FOR RETURNING LEAKED FLUID, LEADING FROM ITS INNER PERIPHERY AND EXTENDING FOR A DESIRED WIDTH.
Claim 20
Independent Claim
64 words
A METHOD FOR MANUFACTURING AN HYDRODYNAMIC OIL SEAL ELEMENT FROM A GENERALLY FLAT WAFTER OF POLYTETRAFLUOROETHYLENE OR THE LIKE, COMPRISING THE STEPS OF: SUBSTANTIALLY SIMULTANEOUSLY BLANKING AND PIERCING SAID WAFTER TO PROVIDE THE DESIRED INNER AND OUTER DIMENSIONS, AND COINING ONE FACE OF SAID WAFER TO PROVIDE HYDRODYNAMIC MEANS FOR RETURNING LEAKED FLUID, LEADING FROM ITS INNER PERIPHERY AND EXTENDING FOR A DESIRED WIDTH.
Claim 21
Dependent Claim
35 words
The method of claim 17 having the additional step of forming each said wafer under pressure to deform the radially inner portion thereof to a frustoconical shape, leaving an outer annular rim that is planar.
Claim 22
Dependent Claim
18 words
The method of claim 17 in which said coining and blanking and piercing steps are performed substantially simultaneously.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-12-29 | 1979-06-30 | 1979-12-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-12-29 | 1983-06-30 | 1983-12-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-12-29 | 1987-06-30 | 1987-12-30 | $7700.00 | Window Closed / Lapsed |