US4334687A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Shaft seal with multi-slitted sleeve
Assignee: Carl Freudenberg KG
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Filing: 1980-11-20
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Granted: 1982-06-15
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Expires: 2000-11-20
Abstract
Abstract A shaft seal for preventing leakage from a gap between a bore hole in a machine housing and a rotating shaft is disclosed. The seal consists of a contact pressure ring of elastic material and a multi-slitted, thin sleeve of polytetrafluoroethylene which is permanently joined to the inner wall of the ring.
Inventors
- 👤 Helmut Holzer
- 👤 Ernst M. von Arndt
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 20:00
CPC Classifications
F; F16; F16J; F16J15/00; F16J15/16; F16J15/32; F16J15/3244; F16J15/3284
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
115 words
A shaft seal for preventing leakage around a rotating shaft, which comprises: a contact pressure ring of elastic material, and a multi-slitted, thin sleeve of polytetrafluoroethylene permanently joined to the inner wall of the ring, The slits forming an angle with the axis of shaft rotation of from about 5° to about 45° and extending radially through the complete sleeve and axially from one end of the sleeve to the other, and the inside diameter of the sleeve being smaller than the diameter of the shaft so that when the seal is assembled onto the shaft, the slits open to form channels through which the elastic material of the ring expands to contact the shaft.
Claim 2
Dependent Claim
115 words
A shaft seal for preventing leakage around a rotating shaft, which comprises: a contact pressure ring of elastic material, and a multi-slitted, thin sleeve of polytetrafluoroethylene permanently joined to the inner wall of the ring, The slits forming an angle with the axis of shaft rotation of from about 5° to about 45° and extending radially through the complete sleeve and axially from one end of the sleeve to the other, and the inside diameter of the sleeve being smaller than the diameter of the shaft so that when the seal is assembled onto the shaft, the slits open to form channels through which the elastic material of the ring expands to contact the shaft.
Claim 3
Dependent Claim
30 words
A seal according to claim 1 wherein the ratio of the inside diameter of the sleeve to the outside diameter of the shaft is from about 0.85 to about 0.95.
Claim 4
Dependent Claim
23 words
A seal according to claim 1 or 2 wherein the slits are straight and form a uniform angle with the axis of rotation.
Claim 5
Dependent Claim
23 words
A seal according to claim 1 or 2 wherein the slits are curved and form a differential angle with the axis of rotation.
Claim 6
Dependent Claim
27 words
A seal according to claim 1 or 2 which further comprises a second set of slits in a mirror symmetry arrangement with the first set of slits.
Claim 7
Dependent Claim
17 words
A seal according to claim 5 wherein the first and second set of slits intersect each other.
Claim 8
Dependent Claim
32 words
A seal according to claim 4 wherein the average of the differential angle formed by each curved slit in relation to the axis of rotation is from about 10° to about 30°.
Claim 9
Dependent Claim
19 words
A gap seal according to claim 1 wherein the entire inner surface of the sleeve rests upon the shaft.
Claim 10
Dependent Claim
46 words
A lip seal according to claim 1 wherein at least one of the end faces of the pressure ring is beveled and the interior portion of the inner diameter surface of the seal is raised off the shaft to form at least one circular sealing lip.
Claim 11
Dependent Claim
32 words
A lip seal according to claim 9 which further comprises a stiffening ring with a circular projection which is mated to a circular slot in an end face of the pressure ring.
Claim 12
Dependent Claim
16 words
A lip seal according to claim 9 or 10 wherein one circular sealing lip is formed.
Claim 13
Dependent Claim
16 words
A lip seal according to claim 9 or 10 wherein two circular sealing lips are formed.
Claim 14
Dependent Claim
55 words
A seal according to claim 1 or 2 wherein after assembly of the seal, the sleeve material between the channels has the form of plates with parallel adjacent boundary edges and the ratio of the width of the plates in the circumferential direction to the width of the channels is a maximum of about 15.
Claim 15
Dependent Claim
15 words
A seal according to claim 1 or 2 wherein the pressure ring is elastic material.
Claim 16
Dependent Claim
31 words
A seal according to claim 1 or 2 which further comprises a flange-shaped member joined to a diaphragm-like circular member which is joined to an end face of the pressure ring.
Claim 17
Dependent Claim
43 words
A seal according to claim 1 or 2 wherein the helical twist of the angles of the slits in relation to the axis of rotation combines with the rotational movement of the shaft to produce a conveyance effect toward the sealed off medium.
Claim 18
Dependent Claim
20 words
A seal according to claim 1 or 2 wherein the sleeve is from about 0.2 to about 0.3 mm thick.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1985-06-14 | 1985-12-14 | 1986-06-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1989-06-14 | 1989-12-14 | 1990-06-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1993-06-14 | 1993-12-14 | 1994-06-15 | $7700.00 | Window Closed / Lapsed |