US5032335A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Manufacture of sealing elements of composite sintered polymeric material
Assignee: Federal Mogul World Wide LLC
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Filing: 1989-07-12
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Granted: 1991-07-16
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Expires: 2009-07-12
Abstract
Abstract A sealing element for use with a radial lip oil seal includes a mounting section formed of a first polymer and a sealing section formed of a second polymer. The sealing element sections are bonded together during a common sintering operation so that each polymer is sintered only once. This reduces molecular degradation of the polymers typically caused by multiple sintering operations.
Inventors
- 👤 David Wilson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 13:58
CPC Classifications
B; B29; B29B; B29B11/00; B29B11/04; B29C; B29C43/00; B29C43/006; B29C43/02; B29C43/027; B29C43/14; B29C43/146; B29C43/20; B29C43/203; B29C65/00; B29C65/02; B29C66/00; B29C66/50; B29C66/51; B29C66/54; B29C66/545; B29C66/70; B29C66/71; B29C66/80; B29C66/83; B29C66/832; B29C66/8322; B29D; B29D99/00; B29D99/0053; C; C08; C08J; C08J5/00; C08J5/12; C08J5/121; F; F16; F16J; F16J15/00; F16J15/16; F16J15/32; F16J15/3204; F16J15/3228; F16J15/328; B29C2043/029; B29C2793/00; B29C66/01; B29C66/05; B29C66/10; B29C66/11; B29C66/112; B29C66/1122; B29C66/52; B29C66/522; B29C66/5227; B29C66/52271; B29C66/52272; B29C66/543; B29C66/72; B29C66/721; B29C66/7212; B29C66/7214; B29C66/72143; B29C66/73; B29C66/731; B29C66/7311; B29C66/73111; B29C66/73112; B29K; B29K2027/00; B29K2027/12; B29K2027/18; B29K2105/00; B29K2105/06; B29K2105/16; B29L; B29L2009/00; B29L2031/00; B29L2031/26; C08J2327/00; C08J2327/02; C08J2327/12
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
162 words
A method of forming annular sealing elements comprising the steps of: a. forming a first tubular preform by applying pressure in a range of 250 to 2500 PSI, without heat, to a confined mass of polymer powders comprising polytetrafluoroethylene; b. forming a second tubular preform by applying pressure in a range of 250 to 2500 PSI, without heat, to a confined mass of polymer powders comprising flourine-based polymer; c. arranging said first and second tubular preforms concentrically one within the other, to form a composite tube; d. applying pressure in the range of 2,000 to 20,000 PSI to said composite tube, to thus compact the tube and form a mechanical bond across the polymer powders at the annular interface between the two preforms; e. heating the compacted composite tube to sinter the polymers and achieve coalescence of the polymers at their annular interface, and f. slicing through said heated compacted composite tube along radial planes so as to form said sealing elements.
Claim 2
Independent Claim
162 words
A method of forming annular sealing elements comprising the steps of: a. forming a first tubular preform by applying pressure in a range of 250 to 2500 PSI, without heat, to a confined mass of polymer powders comprising polytetrafluoroethylene; b. forming a second tubular preform by applying pressure in a range of 250 to 2500 PSI, without heat, to a confined mass of polymer powders comprising flourine-based polymer; c. arranging said first and second tubular preforms concentrically one within the other, to form a composite tube; d. applying pressure in the range of 2,000 to 20,000 PSI to said composite tube, to thus compact the tube and form a mechanical bond across the polymer powders at the annular interface between the two preforms; e. heating the compacted composite tube to sinter the polymers and achieve coalescence of the polymers at their annular interface, and f. slicing through said heated compacted composite tube along radial planes so as to form said sealing elements.
Claim 3
Dependent Claim
17 words
The method of claim 1 wherein prior to said heating said polymers are of virgin unsintered material.
Claim 4
Dependent Claim
23 words
The method of claim 1 wherein the pressure applied in step a is substantially the same as the pressure applied in step b.
Claim 5
Dependent Claim
23 words
The method of claim 1 wherein a heating temperature in the range of 650° F. to 750° F. is used in step e.
Claim 6
Dependent Claim
32 words
The method of claim 1 wherein the first and second tubular preforms are left untreated and uncoated during the period between their initial formation and their being concentrically arranged, per step c.
Claim 7
Dependent Claim
17 words
The method of claim 1, wherein said heating comprises free sintering said compacted tube n an oven.
References Cited (Backward Citations)
US3311522A
Cited
US3255278A
Cited
US4102966A
Cited
US4243235A
Cited
US4364884A
Cited
US4391861A
Cited
US4937025A
Cited
US4900629A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1994-07-15 | 1995-01-14 | 1995-07-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-07-15 | 1999-01-14 | 1999-07-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2002-07-15 | 2003-01-14 | 2003-07-16 | $7700.00 | Window Closed / Lapsed |