US4580790A
Expired / Lapsed
US
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Sintered polytetrafluoroethylene composite material and seal assembly
Assignee: The AT&T MVPD Group LLC
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Filing: 1984-06-21
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Granted: 1986-04-08
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Expires: 2004-06-21
Abstract
Abstract A composition of matter adapted for use as a sealing material and in fabricating bushings, rider rings and structural support pads. The composition is sintered polytetrafluoroethylene (PTFE) having uniformly dispersed therein from 5 to 50 volume percent of filler particles selected from the group consisting of glass particles and mineral particles having a Rockwell C hardness of between 10 C to 50 C wherein the filler particles are present in the polytetrafluoroethylene when the sintering occurs. Lead glass, soda-lead glass and soda-lime glass are among the filler particles which are incorporated into the PTFE to form structurally strong compositions which generate low amounts of wear debris.
Inventors
- 👤 Paul R. Doose
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 21:25
CPC Classifications
C; C09; C09K; C09K3/00; C09K3/10; C09K3/1006; C09K3/1009; C08; C08K; C08K3/00; C08K3/01; C08K3/013; C08K3/40; C09K2200/00; C09K2200/02; C09K2200/0243; C09K2200/0252; Y; Y10; Y10S; Y10S277/00; Y10S277/935; Y10S277/936; Y10S277/937; Y10S277/944; Y10S277/945; Y10S277/946
Claims Analysis
Total Claims: 23
Claim 1
Independent Claim
55 words
A composition of matter comprising: sintered polytetrafluoroethylene having uniformly dispersed therein from 5 to 50 volume percent of filler particles selected from the group consisting of glass particles and mineral particles having a Rockwell C hardness of between about 10C to 50C wherein said filler particles are present in the polytetrafluoroethylene when the sintering occurs.
Claim 2
Dependent Claim
55 words
A composition of matter comprising: sintered polytetrafluoroethylene having uniformly dispersed therein from 5 to 50 volume percent of filler particles selected from the group consisting of glass particles and mineral particles having a Rockwell C hardness of between about 10C to 50C wherein said filler particles are present in the polytetrafluoroethylene when the sintering occurs.
Claim 3
Dependent Claim
14 words
A composition of matter according to claim 1 wherein said filler particles are glass.
Claim 4
Dependent Claim
21 words
A composition of matter according to claim 2 wherein said glass is lead glass, soda-lead glass, soda-lime glass or borosilicate glass.
Claim 5
Dependent Claim
16 words
A composition of matter according to claim 1 wherein said mineral is gypsum, calcite or apatite.
Claim 6
Dependent Claim
26 words
A composition of matter according to claim 1 wherein said filler particles are sufficiently small to pass through a screen having a mesh size of 325.
Claim 7
Dependent Claim
16 words
A composition of matter according to claim 5 wherein said particles have a random angular shape.
Claim 8
Dependent Claim
15 words
A composition of matter according to claim 1 wherein said filler particles are lead glass.
Claim 9
Dependent Claim
21 words
A composition of matter according to claim 7 wherein said lead glass contains from 1 to 70 weight percent lead oxide.
Claim 10
Dependent Claim
19 words
A composition according to claim 7 wherein said lead glass contains from 50 to 70 weight percent lead oxide.
Claim 11
Dependent Claim
21 words
A composition of matter according to claim 7 wherein said sintered polytetrafluoroethylene contains from 20 to 50 weight percent lead glass.
Claim 12
Dependent Claim
21 words
A composition of matter according to claim 1 wherein said sintered polytetrafluoroethylene contains from 10 to 30 weight percent soda-lead glass.
Claim 13
Dependent Claim
23 words
A composition of matter according to claim 2 wherein the sintering temperature of the polytetrafluoroethylene is above the annealing point of said glass.
Claim 14
Dependent Claim
21 words
A composition of matter according to claim 12 wherein said glass is lead glass, soda-lead glass, soda-lime glass or borosilicate glass.
Claim 15
Dependent Claim
67 words
A composition of matter comprising: sintered polytetrafluoroethylene having uniformly dispersed therein from 5 to 50 volume percent of filler particles selected from the group consisting of glass particles having a Rockwell C hardness of between about 10C to 50C wherein said filler particles are present in the polytetrafluoroethylene when the sintering occurs and wherein the temperature of said sintering is above the annealing point of said glass.
Claim 16
Dependent Claim
67 words
A composition of matter comprising: sintered polytetrafluoroethylene having uniformly dispersed therein from 5 to 50 volume percent of filler particles selected from the group consisting of glass particles having a Rockwell C hardness of between about 10C to 50C wherein said filler particles are present in the polytetrafluoroethylene when the sintering occurs and wherein the temperature of said sintering is above the annealing point of said glass.
Claim 17
Dependent Claim
60 words
A composition of matter according to claim 14 wherein said glass is lead glass or soda-lead glass and said sintering temperature is above the melting point of lead and wherein the polytetrafluoroethylene is maintained at the sintering temperature for a sufficient time and the atmosphere surrounding said polytetrafluoroethylene is sufficiently oxygen free to form metallic lead within said sintered polytetrafluoroethylene.
Claim 18
Dependent Claim
38 words
A composition of matter according to claim 15 wherein sufficient oxygen is provided in the atmosphere surrounding said polytetrafluoroethylene during the sintering to prevent the lead oxide in said lead glass or soda-lead glass from forming metallic lead.
Claim 19
Dependent Claim
131 words
In a seal assembly including a first member having a first sealable surface, said first surface having a first Rockwell hardness, a second member having a second sealable surface located in sealing relation to said first sealable surface, said second surface having a second Rockwell hardness, said seal assembly further including sealing material located between said first and second sealable surfaces to provide a seal therebetween, wherein the improvement comprises: sealing material comprising a sintered polytetrafluoroethylene having uniformly dispersed therein from 5 to 50 volume percent of glass filler particles having a Rockwell C hardness of between about 10C to 50C wherein said filler particles are present in the polytetrafluoroethylene when the sintering occurs and wherein the temperature of said sintering is above the annealing point of said glass filler particles.
Claim 20
Dependent Claim
131 words
In a seal assembly including a first member having a first sealable surface, said first surface having a first Rockwell hardness, a second member having a second sealable surface located in sealing relation to said first sealable surface, said second surface having a second Rockwell hardness, said seal assembly further including sealing material located between said first and second sealable surfaces to provide a seal therebetween, wherein the improvement comprises: sealing material comprising a sintered polytetrafluoroethylene having uniformly dispersed therein from 5 to 50 volume percent of glass filler particles having a Rockwell C hardness of between about 10C to 50C wherein said filler particles are present in the polytetrafluoroethylene when the sintering occurs and wherein the temperature of said sintering is above the annealing point of said glass filler particles.
Claim 21
Dependent Claim
21 words
An improved seal assembly according to claim 17 wherein said glass is lead glass, soda-lead glass, soda-lime glass or borosilicate glass.
Claim 22
Dependent Claim
28 words
An improved seal assembly according to claim 17 wherein said first and second members are made from material having a Rockwell C hardness of from 20 to 65.
Claim 23
Dependent Claim
19 words
An improved seal assembly according to claim 19 wherein said first and second members are made of carbon steel.
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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) | 1989-04-07 | 1989-10-07 | 1990-04-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-04-07 | 1993-10-07 | 1994-04-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-04-07 | 1997-10-07 | 1998-04-08 | $7700.00 | Window Closed / Lapsed |