Patent US3651908A successfully refreshed from Google Patents.
US3651908A
Expired / Lapsed
US
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Sprag clutches
Assignee: Renold Ltd
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Filing: 1970-06-01
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Granted: 1972-03-28
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Expires: 1990-06-01
Abstract
Abstract A sprag clutch in which the forces on the sprags during outer race over running give rise to only a small but positive rubbing load between the sprags and the inner race at all outer race over running speeds within a designed limit.
Inventors
- 👤 Benjamin D Oldfield
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 18:55
CPC Classifications
F; F16; F16D; F16D41/00; F16D41/06; F16D41/069; F16D41/07
Claims Analysis
Total Claims: 29
Claim 1
Independent Claim
229 words
A sprag-retainer assemblage for use in a sprag clutch, in an annular gap between inner and outer races of the clutch to transmit unidirectional drive between the clutch driving and driven race, the assemblage comprising an annular sprag retainer, a ring of sprags in the retainer, and, for each sprag an energising spring individual to the sprag for biasing the sprag into substantially line contact with the inner race of the clutch, by tilting the sprag substantially about a line of contact with the outer race of the clutch, with a component of spring force directed radially inwardly of the assemblage, such that the centrifugal force acting on the spring during overrunning of the outer race of the clutch relieves the spring force on the sprag, the centre of gravity of each sprag being disposed close to or in the radial axial plane of the assemblage containing said line of contact between said sprag and the outer race during over-running of the outer race of the clutch such that the centrifugal force acting on the sprag during overrunning of the outer race of the clutch acts in conjunction with the spring force on the sprag so as to maintain a small but positive load between the sprag and the inner race on over run of the outer race, at least within a predetermined limit of outer race over-running speed.
Claim 2
Dependent Claim
229 words
A sprag-retainer assemblage for use in a sprag clutch, in an annular gap between inner and outer races of the clutch to transmit unidirectional drive between the clutch driving and driven race, the assemblage comprising an annular sprag retainer, a ring of sprags in the retainer, and, for each sprag an energising spring individual to the sprag for biasing the sprag into substantially line contact with the inner race of the clutch, by tilting the sprag substantially about a line of contact with the outer race of the clutch, with a component of spring force directed radially inwardly of the assemblage, such that the centrifugal force acting on the spring during overrunning of the outer race of the clutch relieves the spring force on the sprag, the centre of gravity of each sprag being disposed close to or in the radial axial plane of the assemblage containing said line of contact between said sprag and the outer race during over-running of the outer race of the clutch such that the centrifugal force acting on the sprag during overrunning of the outer race of the clutch acts in conjunction with the spring force on the sprag so as to maintain a small but positive load between the sprag and the inner race on over run of the outer race, at least within a predetermined limit of outer race over-running speed.
Claim 3
Dependent Claim
41 words
A sprag-retainer assemblage as claimed in claim 1 wherein the centrifugal force acting on each sprag during over-running of the outer race of the clutch passes through said line of contact of the sprag with the outer race of the clutch.
Claim 4
Dependent Claim
61 words
A sprag-retainer assemblage as claimed in claim 1 wherein the centrifugal force acting on each sprag during over-running of the outer race of the clutch passes to that side of said line of contact of the sprag with the outer race of the clutch such as to oppose the spring force tending to tilt the sprag about said line, as aforesaid.
Claim 5
Dependent Claim
15 words
A sprag-retainer assemblage as claimed in claim 1 wherein said spring is a blade spring.
Claim 6
Dependent Claim
35 words
A sprag-retainer assemblage as claimed in claim 4 wherein the blade spring comprises a lightweight, elongated arm anchored to the sprag retainer at one end, the other, free end of the arm engaging the sprag.
Claim 7
Dependent Claim
39 words
A sprag-retainer assemblage as claimed in claim 5 wherein said spring arm is anchored at its radially inner end, the arm extending outwardly at an angle to the radial direction to its other, free end which engages the sprag.
Claim 8
Dependent Claim
43 words
A sprag-retainer assemblage as claimed in claim 6 wherein the blade spring is of U-shape comprising a further elongated arm joined with said first said elongated arm at its radially inner end, and said further elongated arm is attached to the sprag retainer.
Claim 9
Dependent Claim
24 words
A sprag retainer as claimed in claim 7 wherein said further elongated arm is permanently attached to the retainer, for example, by being moulded-in.
Claim 10
Dependent Claim
19 words
A sprag retainer as claimed in claim 7 wherein said further elongated arm is removably attached to the retainer.
Claim 11
Dependent Claim
26 words
A sprag retainer as claimed in claim 9 wherein said further elongated arm makes interlocking engagement in an axially and radially extending pocket in the retainer.
Claim 12
Dependent Claim
70 words
A sprag-retainer assemblage as claimed in claim 1 wherein the sprags are positioned each in a separate compartment in the sprag retainer having oppositely facing circumferentially spaced bounding faces which co-operate with one another, in use of the assemblage, to prevent rotation of the sprag in either direction to a position beyond a limiting position in which it can move out of driving contact with the inner and outer races.
Claim 13
Dependent Claim
65 words
A sprag-retainer assemblage as claimed in claim 11 wherein said oppositely facing bounding faces define a funnel shape in radial planes normal to the axis of the assemblage, the faces having portions converging radially outwardly to substantially parallel portions thereof which portions co-operate with curved surface portions of the sprag to position the sprag circumferentially relative to the other sprags in use of the assemblage.
Claim 14
Dependent Claim
57 words
A sprag-retainer assemblage as claimed in claim 12 wherein said funnel shape is assymetrical, being enlarged on that side of the axial radial plane of the assemblage which contains the centre of gravity of the sprag which is remote from the low corner of the radially inner end face of the sprag in use of the assemblage.
Claim 15
Dependent Claim
62 words
A sprag-retainer assemblage as claimed in claim 12 wherein the sprags and the retainer have interlocking formations which are urged into interlocking engagement with one another by the springs individual to the sprags so long as the assemblage is free of any races, the interlocking formations then resisting radially inward or radially outward displacement of the sprags with respect to the retainer.
Claim 16
Dependent Claim
34 words
A sprag-retainer assemblage as claimed in claim 14 wherein the interlocking formations comprise, in each case, an axially extending part-cylindrical bead on the retainer and an axially extending smoothly curved concavity in the sprag.
Claim 17
Dependent Claim
39 words
A sprag retainer assemblage as claimed in claim 15 wherein the bead is formed at the junction of the surface portions of one of said oppositely facing bounding faces of the compartment in the sprag retainer cOntaining the sprag.
Claim 18
Dependent Claim
18 words
A sprag-retainer assemblage as claimed in claim 1 wherein the retainer is formed as or comprises a moulding.
Claim 19
Dependent Claim
19 words
A sprag-retainer assemblage as claimed in claim 1 wherein the retainer is formed as or comprises a plastic moulding.
Claim 20
Dependent Claim
41 words
A sprag-retainer assemblage as claimed in claim 1 wherein the retainer comprises an annular body and an annular end piece fixed to the body, the end piece defining one of two axially spaced bounding faces of each compartment of the retainer.
Claim 21
Dependent Claim
18 words
A sprag-retainer assemblage as claimed in claim 19 wherein the end piece is removably fixed to the body.
Claim 22
Dependent Claim
32 words
A sprag-retainer assemblage as claimed in claim 20 wherein the body is flexible and the body and the end piece have a groove-and-lip connection engageable and disengageable by flexure of the body.
Claim 23
Dependent Claim
55 words
A sprag-retainer assemblage as claimed in claim 12 wherein the retainer comprises a cage ring having a circumferentially extending row of window openings in alternate ones of which inserts are mounted to define portions of said oppositely facing bounding faces of said compartments, the sprags being located one in each of the other window openings.
Claim 24
Dependent Claim
42 words
A sprag-retainer assemblage as claimed in claim 22 wherein the inserts define radially outwardly converging portions of said oppositely facing bounding faces of said compartments, the window openings containing the sprags presenting said substantially parallel portions of said oppositely facing bounding faces.
Claim 25
Dependent Claim
25 words
A sprag-retainer assemblage as claimed in claim 22 wherein the cage ring is of metal and the inserts are of plastic material e.g. plastic mouldings.
Claim 26
Dependent Claim
20 words
A sprag-retainer assemblage as claimed in claim 22 wherein the inserts are composed of an extruded section of plastic material.
Claim 27
Dependent Claim
227 words
A sprag clutch comprising inner and outer races defining an annular gap and a sprag-retainer assemblage in the annular gap to transmit unidirectional drive between the clutch driving and driven race, said assemblage comprising an annular sprag retainer, a ring of sprags in the retainer, and, for each sprag, an energising spring individual to the sprag and biasing the sprag into substantially line contact with the inner race of the clutch by tilting the sprag about substantially a line of contact with the outer race of the clutch, with a component of spring force directed radially inwardly of the clutch whereby the centrifugal force acting on the spring during over-running of the outer race of the clutch relieves the spring force on the sprag, the centre of gravity of each sprag being disposed close to or in the radial axial plane of the clutch containing said line of contact between said sprag and the outer race during over-running of the outer race of the clutch such that the centrifugal force acting on the sprag during over-running of the outer race of the clutch acts in conjunction with the spring force on the sprag so as to maintain a small but positive load between the sprag and the inner race on over run of the outer race, at least within a predetermined limit of outer race over-running speed.
Claim 28
Dependent Claim
227 words
A sprag clutch comprising inner and outer races defining an annular gap and a sprag-retainer assemblage in the annular gap to transmit unidirectional drive between the clutch driving and driven race, said assemblage comprising an annular sprag retainer, a ring of sprags in the retainer, and, for each sprag, an energising spring individual to the sprag and biasing the sprag into substantially line contact with the inner race of the clutch by tilting the sprag about substantially a line of contact with the outer race of the clutch, with a component of spring force directed radially inwardly of the clutch whereby the centrifugal force acting on the spring during over-running of the outer race of the clutch relieves the spring force on the sprag, the centre of gravity of each sprag being disposed close to or in the radial axial plane of the clutch containing said line of contact between said sprag and the outer race during over-running of the outer race of the clutch such that the centrifugal force acting on the sprag during over-running of the outer race of the clutch acts in conjunction with the spring force on the sprag so as to maintain a small but positive load between the sprag and the inner race on over run of the outer race, at least within a predetermined limit of outer race over-running speed.
Claim 29
Dependent Claim
52 words
A sprag-retainer assemblage as claimed in claim 12 wherein said spring is a blade spring which comprises a lightweight, elongated arm anchored to the sprag retainer at its radially inner end, said arm extending outwardly at an angle to the radial direction, the other, free end of said arm engaging the sprag.
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) | 1975-03-28 | 1975-09-27 | 1976-03-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-03-28 | 1979-09-27 | 1980-03-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-03-28 | 1983-09-27 | 1984-03-28 | $7700.00 | Window Closed / Lapsed |