Patent US3082928A successfully refreshed from Google Patents.
Patent US3795178A successfully refreshed from Google Patents.
US3795178A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Hydraulic actuator holding system
Assignee: Individual
•
Filing: 1972-09-11
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Granted: 1974-03-05
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Expires: 1992-09-11
Abstract
Abstract The invention improves on a locking valve for holding a hydraulic actuator in place. The locking valve has a pair of check valves and a shuttle piston movable hydraulically between the check valves for opening the check valves in response to an upstream directional valve for moving the actuator, and the improvement is a central opening in the shuttle piston communicating with a return line, bleed holes communicating with both faces of the shuttle piston and the central opening, and centering springs for the shuttle piston. The valve then locks against back pressure from the hydraulic actuator and also allows any positive leakage from upstream to bleed through the shuttle piston and back through the return line without building up a pressure that can eventually open the valve. The system also includes a loading valve arrangement for maintaining pressure on the hydraulic actuator.
Inventors
- 👤 R Roche
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 19:40
CPC Classifications
F; F15; F15B; F15B13/00; F15B13/01; Y; Y10; Y10T; Y10T137/00; Y10T137/2496; Y10T137/2544; Y10T137/2554; Y10T137/8593; Y10T137/87169; Y10T137/87233; Y10T137/87241
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
281 words
A system having an hydraulic actuator, a pair of actuator lines having alternate flow for moving said actuator, a control valve, a pair of control lines having alternate flow under control of said control valve, and a locking valve for relaying said alternate flow from said control lines to said actuator lines for moving said actuator and for blocking said actuator lines to hold said said actuator in place in the absence of flow from said control valve, said system comprising: a. said locking valve having a shuttle piston with a central opening, and a pair of check valves axially aligned with said shuttle piston on opposite sides of said shuttle piston; b. said control lines communicating with opposite faces of said shuttle piston and respective ones of said check valves for alternatively opening one of said check valves by hydraulic pressure and moving said shuttle piston to engage and open the other one of said check valves; c. a return line having a check valve and communicating with said central opening when said shuttle piston is in a central position between said check valves, said return line bypassing said control valve; d. centering spring means for biasing said shuttle piston toward said central position; and e. said shuttle piston having bleed holes communicating with both faces of said shuttle piston and said central opening for bleeding any positive leakage from said control valve through said control lines into said central opening and through said return line without opening said check valves and without moving said shuttle position from said central position, said return line being blocked by said shuttle piston when said shuttle piston opens either of said check valves.
Claim 2
Independent Claim
281 words
A system having an hydraulic actuator, a pair of actuator lines having alternate flow for moving said actuator, a control valve, a pair of control lines having alternate flow under control of said control valve, and a locking valve for relaying said alternate flow from said control lines to said actuator lines for moving said actuator and for blocking said actuator lines to hold said said actuator in place in the absence of flow from said control valve, said system comprising: a. said locking valve having a shuttle piston with a central opening, and a pair of check valves axially aligned with said shuttle piston on opposite sides of said shuttle piston; b. said control lines communicating with opposite faces of said shuttle piston and respective ones of said check valves for alternatively opening one of said check valves by hydraulic pressure and moving said shuttle piston to engage and open the other one of said check valves; c. a return line having a check valve and communicating with said central opening when said shuttle piston is in a central position between said check valves, said return line bypassing said control valve; d. centering spring means for biasing said shuttle piston toward said central position; and e. said shuttle piston having bleed holes communicating with both faces of said shuttle piston and said central opening for bleeding any positive leakage from said control valve through said control lines into said central opening and through said return line without opening said check valves and without moving said shuttle position from said central position, said return line being blocked by said shuttle piston when said shuttle piston opens either of said check valves.
Claim 3
Dependent Claim
45 words
The system of claim 1 wherein abutment means limits the travel of said shuttle piston, and said bleed holes are blocked by said abutment means at the limits of travel of said shuttle piston to prevent any bleed during said flow from said control valve.
Claim 4
Dependent Claim
39 words
The system of claim 1 including a pair of normally closed and manually openable shut-off valves connected between said return line and said actuator lines for manually bypassing said locking valve and said check valve in said return line.
Claim 5
Dependent Claim
53 words
The system of claim 1 wherein said locking valve has a plurality of housing parts joined together along generally transverse planes, and O-ring seals are arranged between said parts along said transverse planes so any leakage between said parts is external to said valve and visible from outside said valve to facilitate repair.
Claim 6
Dependent Claim
19 words
The system of claim 1 wherein said check valves of said locking valve have seats formed of resilient plastic.
Claim 7
Dependent Claim
115 words
The system of claim 1 including a high-pressure line bypassing said control valve, one pair of double-check valves having bleed through passages for limited flow in one direction being supplied by said high pressure line and outputting into respective ones of said control lines, and another pair of double-check valves having bleed through passages for limited flow in one direction being supplied by respective ones of said control lines and outputting into said return line, said pairs of double-check valves cooperating for maintaining pressure in one of said control lines to hold said check valves of said locking valve open to maintain pressure on said actuator at a limit of motion position of said actuator.
Claim 8
Dependent Claim
58 words
The system of claim 1 wherein said check valves of said locking valve have seats formed of resilient plastic, abutment means limits the travel of said shuttle piston, and said bleed holes are blocked by said abutment means at the limits of travel of said shuttle piston to prevent any bleed during said flow from said control valve.
Claim 9
Dependent Claim
39 words
The system of claim 7 including a pair of normally closed and manually openable shut-off valves connected between said return line and said actuator lines for manually bypassing said locking valve and Said check valve in said return line.
Claim 10
Dependent Claim
115 words
The system of claim 8 including a high-pressure line bypassing said control valve, one pair of double-check valves having bleed through passages for limited flow in one direction being supplied by said high pressure line and outputting into respective ones of said control lines, and another pair of double-check valves having bleed through passages for limited flow in one direction being supplied by respective ones of said control lines and outputting into said return line, said pairs of double-check valves cooperating for maintaining pressure in one of said control lines to hold said check valves of said locking valve open to maintain pressure on said actuator at a limit of motion position of said actuator.
Claim 11
Dependent Claim
53 words
The system of claim 9 wherein said locking valve has a plurality of housing parts joined together along generally transverse planes, and O-ring seals are arranged between said parts along said transverse planes so any leakage between said parts is external to said valve and visible from outside said valve to facilitate repair.
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) | 1977-03-04 | 1977-09-03 | 1978-03-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-03-04 | 1981-09-03 | 1982-03-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-03-04 | 1985-09-03 | 1986-03-05 | $7700.00 | Window Closed / Lapsed |