US3568570A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Anticreep hydraulic positioning system
Assignee: Babcock and Wilcox Co
•
Filing: 1969-03-05
•
Granted: 1971-03-09
•
Expires: 1989-03-05
Abstract
Abstract A hydraulically actuatable piston which is subjected to a constant bias (e.g. gravity) in a direction opposite to that in which it is movable under hydraulic pressure is provided with means for accurately maintaining a stationary piston positioning under hydrostatic pressure despite leakage past the piston by a metering valve actuatable by differential movement between the piston and cylinder, fluid being constantly supplied to the underside of the piston and metered past the valve.
Inventors
- 👤 Gordon R Winders
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 09:15
CPC Classifications
F; F15; F15B; F15B15/00; F15B15/08; F15B15/14; F15B15/149; F15B15/1423; F15B15/1447
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
187 words
Hydraulic actuating and positioning means comprising a cylinder part and a piston part, means to deliver fluid to a space in the cylinder on one side of the piston to move the piston, and to trap fluid in such space to substantially immobilize the piston, and means for preventing unwanted movement of the piston when the fluid is trapped, comprising supplemental makeup fluid delivery means connected to said space and having a fluid delivery capacity in excess of the rate of leakage past the piston, and flow control means responsive to relative movement of the piston and cylinder for variably controlling the effective maintenance of makeup fluid in said space in proportion to leakage past the piston as measured by such relative movement, said flow control means comprising a bypass passage past the piston, a valve movable to vary the rate of flow through said passage, and actuating means for the valve comprising a member having limited lost motion connection to the piston and having a friction-slip connection to the cylinder, the frictional resistance of the friction-slip connection exceeding the resistance of said valve to operative movement.
Claim 2
Dependent Claim
187 words
Hydraulic actuating and positioning means comprising a cylinder part and a piston part, means to deliver fluid to a space in the cylinder on one side of the piston to move the piston, and to trap fluid in such space to substantially immobilize the piston, and means for preventing unwanted movement of the piston when the fluid is trapped, comprising supplemental makeup fluid delivery means connected to said space and having a fluid delivery capacity in excess of the rate of leakage past the piston, and flow control means responsive to relative movement of the piston and cylinder for variably controlling the effective maintenance of makeup fluid in said space in proportion to leakage past the piston as measured by such relative movement, said flow control means comprising a bypass passage past the piston, a valve movable to vary the rate of flow through said passage, and actuating means for the valve comprising a member having limited lost motion connection to the piston and having a friction-slip connection to the cylinder, the frictional resistance of the friction-slip connection exceeding the resistance of said valve to operative movement.
Claim 3
Dependent Claim
182 words
Hydraulic actuating and positioning means comprising a cylinder part and a piston part, means to deliver fluid to a space in the cylinder on one side of the piston to move the piston, and to trap fluid in such space to substantially immobilize the piston, and means for preventing unwanted movement of the piston when the fluid is trapped, comprising supplemental makeup fluid delivery means connected to said space and having a fluid delivery capacity in excess of the rate of leakage past the piston, and flow control means responsive to relative movement of the piston and cylinder for variably controlling the effective maintenance of makeup fluid in said space in proportion to leakage past the piston as measured by such relative movement, wherein said flow control means comprises a valve movable to vary said rate of flow and actuating means for the valve comprising a member having a friction-slip connection to one of said parts and a limited lost motion connection to the other part, the frictional resistance of the friction-slip connection exceeding the resistance of said valve to operative movement.
Claim 4
Dependent Claim
182 words
Hydraulic actuating and positioning means comprising a cylinder part and a piston part, means to deliver fluid to a space in the cylinder on one side of the piston to move the piston, and to trap fluid in such space to substantially immobilize the piston, and means for preventing unwanted movement of the piston when the fluid is trapped, comprising supplemental makeup fluid delivery means connected to said space and having a fluid delivery capacity in excess of the rate of leakage past the piston, and flow control means responsive to relative movement of the piston and cylinder for variably controlling the effective maintenance of makeup fluid in said space in proportion to leakage past the piston as measured by such relative movement, wherein said flow control means comprises a valve movable to vary said rate of flow and actuating means for the valve comprising a member having a friction-slip connection to one of said parts and a limited lost motion connection to the other part, the frictional resistance of the friction-slip connection exceeding the resistance of said valve to operative movement.
Claim 5
Dependent Claim
24 words
Means as defined in claim 2 including an escape passage from said space, said valve being arranged to vary the flow through said passage.
Claim 6
Dependent Claim
17 words
Means as defined in claim 3 wherein said escape passage and valve are carried by the piston.
Claim 7
Dependent Claim
31 words
Means as defined in claim 4 wherein said member for actuating the valve comprises a piston ring having lost motion connection to the piston and a friction fit in the cylinder.
Claim 8
Dependent Claim
17 words
Means as defined in claim 3 wherein the escape passage and valve are carried by the cylinder.
Claim 9
Dependent Claim
29 words
Means as defined in claim 6 wherein said member for actuating the valve has a limited lost motion connection to the cylinder and a frictional-slip connection to the piston.
Claim 10
Dependent Claim
16 words
Means as defined in claim 2 wherein said valve is in said supplemental fluid delivery means.
References Cited (Backward Citations)
US599618A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-03-08 | 1974-09-07 | 1975-03-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-03-08 | 1978-09-07 | 1979-03-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-03-08 | 1982-09-07 | 1983-03-09 | $7700.00 | Window Closed / Lapsed |