Patent US3022230A successfully refreshed from Google Patents.
US3554387A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Buffers and draw gear for railways, tramways and like vehicles
Assignee: Oleo International Holdings Ltd
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Filing: 1968-07-22
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Granted: 1971-01-12
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Expires: 1988-07-22
Abstract
Abstract A hydraulic buffer or draw gear shock absorber for rail vehicles having means to control flow of liquid from a compression chamber in a cylinder into a reservoir chamber in a hollow plunger which flow control means provide flow restriction of different characteristics during slow inward plunger movement and during rapid inward plunger movement respectively, the said control means comprising a sleeve which, during slow inward plunger movement cooperates with a seat in the cylinder to provide substantially no flow until a predetermined pressure is built up in the compression chamber and during rapid inward plunger movement, moves away from the seat and cooperates with a profiled member to provide increasing flow restriction as the buffer plunger moves inwardly.
Inventors
- 👤 Peter W Thornhill
- 👤 Quinton H Carlton
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 07:50
CPC Classifications
B; B61; B61G; B61G11/00; B61G11/12
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
272 words
A hydraulic buffer or draw gear shock absorber for railway, tramway or the like vehicles comprising a cylinder unit, a plunger unit adapted to be forced into said cylinder unit when a load is applied to said buffer or draw gear shock absorber, a compression chamber and a reservoir chamber; said plunger unit acting to displace liquid from said compression chamber to said reservoir chamber when said plunger unit is forced into said cylinder unit; resilient means to provide a recoil force opposing inward movement of said plunger, and flow restricting means to control the flow of liquid from said compression chamber to said reservoir chamber; said flow-restricting means comprising a member cooperating with a seat during slow movement of said plunger unit relative to said cylinder unit to close an escape path for liquid from said compression chamber to said reservoir chamber unless the pressure therein exceeds a value determined by loading means acting on said member; said member comprising a sleeve slidably mounted in said plunger unit so that the bore of said sleeve forms a passage connecting said compression chamber to said reservoir chamber, the seat with which said sleeve cooperates being formed or provided at one end of said cylinder unit and further comprising a profiled member extending from that end of said cylinder into said sleeve; said member during rapid movement of said plunger unit relative to said cylinder unit being moved out of cooperating relation with said seat and cooperating with said profiled member to provide a resistance to liquid flow from said compression chamber which increases as said plunger moves inwardly of said cylinder unit.
Claim 2
Dependent Claim
272 words
A hydraulic buffer or draw gear shock absorber for railway, tramway or the like vehicles comprising a cylinder unit, a plunger unit adapted to be forced into said cylinder unit when a load is applied to said buffer or draw gear shock absorber, a compression chamber and a reservoir chamber; said plunger unit acting to displace liquid from said compression chamber to said reservoir chamber when said plunger unit is forced into said cylinder unit; resilient means to provide a recoil force opposing inward movement of said plunger, and flow restricting means to control the flow of liquid from said compression chamber to said reservoir chamber; said flow-restricting means comprising a member cooperating with a seat during slow movement of said plunger unit relative to said cylinder unit to close an escape path for liquid from said compression chamber to said reservoir chamber unless the pressure therein exceeds a value determined by loading means acting on said member; said member comprising a sleeve slidably mounted in said plunger unit so that the bore of said sleeve forms a passage connecting said compression chamber to said reservoir chamber, the seat with which said sleeve cooperates being formed or provided at one end of said cylinder unit and further comprising a profiled member extending from that end of said cylinder into said sleeve; said member during rapid movement of said plunger unit relative to said cylinder unit being moved out of cooperating relation with said seat and cooperating with said profiled member to provide a resistance to liquid flow from said compression chamber which increases as said plunger moves inwardly of said cylinder unit.
Claim 3
Dependent Claim
34 words
A hydraulic buffer or draw gear shock absorber according to claim 1, wherein the loading means acting on the sleeve are constituted by the resilient means providing the recoil force on the plunger unit.
Claim 4
Dependent Claim
63 words
A hydraulic buffer or draw gear shock absorber according to claim 2, wherein the reservoir chamber is formed in the plunger unit, the resilient means providing the recoil force acting through a movable wall on liquid in said reservoir chamber to displace said liquid into the compression chamber when a compressive force acting on the buffer or draw gear shock absorber is relieved.
Claim 5
Dependent Claim
102 words
A hydraulic buffer or draw gear shock absorber according to claim 3, wherein the sleeve is slidable in an opening in the inner end wall of the plunger unit and has a flange at its end which extends into the reservoir chamber which flange is a sliding fit in a tube extending from the said inner end wall of the plunger unit into the reservoir chamber so that an annular space is provided between said tube and the sleeve when the latter is displaced inwardly of said reservoir chamber, the said annular space being sealed against the entry of air or liquid.
Claim 6
Dependent Claim
27 words
A hydraulic buffer or draw gear shock absorber according to claim 4, wherein a nonreturn valve is provided to allow escape of liquid from said annular space.
Claim 7
Dependent Claim
32 words
A hydraulic buffer or draw gear shock absorber according to claim 5, wherein cushioning means are provided to cushion the final portion of the movement of the sleeve into the reservoir chamber.
Claim 8
Dependent Claim
29 words
A hydraulic buffer or draw gear shock absorber according to claim 6, wherein the cushioning is provided by trapping liquid between opposed annular surfaces on the sleeve and tube.
Claim 9
Dependent Claim
23 words
A hydraulic buffer or draw gear shock absorber according to claim 1, wherein the seat for the sleeve is supported by resilient means.
Claim 10
Dependent Claim
33 words
A hydraulic buffer or draw gear shock absorber according to claim 1, wherein at least one nonreturn valve is provided for the return of liquid from the reservoir chamber to the compression chamber.
Claim 11
Dependent Claim
48 words
A hydraulic buffer or draw gear shock absorber according to claim 1, wherein the profiled member in formed with a reduced neck adjacent its larger end, tHe sleeve having a portion of reduced internal diameter which surrounds said neck when the buffer or shock absorber is fully extended.
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) | 1974-01-11 | 1974-07-13 | 1975-01-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-01-11 | 1978-07-13 | 1979-01-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-01-11 | 1982-07-13 | 1983-01-12 | $7700.00 | Window Closed / Lapsed |