US3552273A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Piston and cylinder unit having stroke limiting means
Assignee: Webley and Scott Ltd
•
Filing: 1968-12-11
•
Granted: 1971-01-05
•
Expires: 1988-12-11
Abstract
Abstract A fluid-powered piston and cylinder unit provided with limit means for limiting the stroke of the piston in the cylinder, the limit means comprising a sidewall of an annular recess in the piston and a piston ring accommodated in an annular groove in the cylinder, the ring being spring-loaded radially inwardly so as to project into the piston recess with the recess and groove in register, whereby the piston ring is engageable with the sidewall of the annular rebate positively to limit the piston stroke in one direction.
Inventors
- 👤 Harold Frederick Resuggan
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 21:42
CPC Classifications
B; B66; B66F; B66F3/00; B66F3/24; B66F3/25; B66F3/30; F; F03; F03C; F03C1/00
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
110 words
A fluid-powered piston and cylinder unit wherein the piston is formed with an annular rebate and a piston ring is disposed in an internal annular groove in said cylinder, said ring being spring-loaded radially inwardly so as to project into said annular rebate when said rebate is opposite said groove, a pressure relief valve in said piston, an actuating member for said valve movably mounted on and with respect to said piston, and piston stroke limiting means comprising cooperating abutment surfaces on said ring and member engageable when said ring projects inwardly into said rebate during piston movement in one direction whereby said member is displaced to operate said valve.
Claim 2
Dependent Claim
110 words
A fluid-powered piston and cylinder unit wherein the piston is formed with an annular rebate and a piston ring is disposed in an internal annular groove in said cylinder, said ring being spring-loaded radially inwardly so as to project into said annular rebate when said rebate is opposite said groove, a pressure relief valve in said piston, an actuating member for said valve movably mounted on and with respect to said piston, and piston stroke limiting means comprising cooperating abutment surfaces on said ring and member engageable when said ring projects inwardly into said rebate during piston movement in one direction whereby said member is displaced to operate said valve.
Claim 3
Dependent Claim
40 words
In the piston and cylinder unit defined in claim 1, means defining a further abutment surface on said moving piston adapted to engage said ring after the valve has been operated, to sequentially provide a positive stop for said piston.
Claim 4
Dependent Claim
41 words
In the piston and cylinder unit defined in claim 1, cooperating means on said piston and ring engageable for radially spreading the ring out of said rebate to disengage said abutment surface during movement of the piston in the opposite direction.
Claim 5
Dependent Claim
35 words
A piston and cylinder unit according to claim 1, wherein the piston is provided with a transverse passage accommodating the valve actuating member for movement of the latter axially of the cylinder with the passage.
Claim 6
Dependent Claim
38 words
A piston and cylinder unit according to claim 1, wherein the piston ring and an adjacent part of the cylinder are provided with apertures to permit passage of fluid out of the cylinder from the relieve relief valve.
Claim 7
Dependent Claim
41 words
A piston and cylinder unit according to claim 5, including an elastic garter seal mounted on the cylinder to encircle the apertured part of the latter, whereby passage of fluid from the exterior to the interior of the cylinder is prevented.
Claim 8
Dependent Claim
56 words
A fluid-powered piston and cylinder unit as defined in claim 6, wherein said valve actuating member extends across said piston within said passage which is large enough to permit axial displacement of said member relative to the moving piston, and said abutment surface comprise an axial end of said ring and opposite ends of said member.
Claim 9
Dependent Claim
30 words
A piston and cylinder unit according to claim 1, wherein the piston ring is split and is made of spring metal to provide inherent radial inward spring-loading of the ring.
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) | 1974-01-04 | 1974-07-06 | 1975-01-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-01-04 | 1978-07-06 | 1979-01-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-01-04 | 1982-07-06 | 1983-01-05 | $7700.00 | Window Closed / Lapsed |