Patent US3789737A successfully refreshed from Google Patents.
US3789737A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Self-purging brake actuator
Assignee: Bendix Corp
•
Filing: 1972-03-27
•
Granted: 1974-02-05
•
Expires: 1992-03-27
Abstract
Abstract A brake actuator is disclosed for fluid pressure actuating braking system. The actuator includes an actuating piston slidably mounted within a housing and defining a pair of pressure chambers between opposite ends of the piston and corresponding ends of the housing. High pressure fluid is communicated into one of the chambers where it acts upon the end of the piston to drive the latter in a brake actuating direction. A check valve permits air to exhaust from the other chamber, but prevents atmospheric air from being drawn into the latter when the piston is returned upon release of the brake. A sleeve is slidable relative to the piston and moves relative to the latter when the piston is actuated to prevent communication between the chambers during a brake actuation, but opens the passage upon return movement of the piston upon release of the brakes to permit fluid in the one chamber to communicate into the other chamber, thereby preventing contamination of the latter by atmospheric air.
Inventors
- 👤 R Burnett
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 23:03
CPC Classifications
F; F16; F16D; F16D65/00; F16D65/14; F16D65/28; B; B60; B60T; B60T17/00; B60T17/08
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
234 words
In a fluid actuator: a housing defining a compartment therewithin; piston means slidably mounted in said compartment and dividing the latter into a pair of chambers; means for admitting pressurized fluid into one of said chambers to thereby drive said piston means in an actuating direction; resilient means returning said piston means upon release of said pressurized fluid; passage means extending through said piston means to communicate said chambers; first valve means responsive to movement of said piston means to close said passage means when said piston means is driven in said actuating direction and maintaining said passage means closed until after termination of movement of the piston means in the actuating direction, but opening said passage means to permit communication between said chambers when said resilient means returns said piston means; and second valve means permitting communication between the other chamber and the exterior of the housing, but preventing communication in the reverse direction, said first valve means including slidable means slidably carried by said piston means and moving into sealing engagement with the latter to prevent communication through said passage means when said piston means is urged in the actuating direction, but sliding relative to the piston means to open said passage means when the piston means is urged in the return direction; and resisting means carried by said housing and engaging said slidable means to resist sliding movement of the latter.
Claim 2
Dependent Claim
234 words
In a fluid actuator: a housing defining a compartment therewithin; piston means slidably mounted in said compartment and dividing the latter into a pair of chambers; means for admitting pressurized fluid into one of said chambers to thereby drive said piston means in an actuating direction; resilient means returning said piston means upon release of said pressurized fluid; passage means extending through said piston means to communicate said chambers; first valve means responsive to movement of said piston means to close said passage means when said piston means is driven in said actuating direction and maintaining said passage means closed until after termination of movement of the piston means in the actuating direction, but opening said passage means to permit communication between said chambers when said resilient means returns said piston means; and second valve means permitting communication between the other chamber and the exterior of the housing, but preventing communication in the reverse direction, said first valve means including slidable means slidably carried by said piston means and moving into sealing engagement with the latter to prevent communication through said passage means when said piston means is urged in the actuating direction, but sliding relative to the piston means to open said passage means when the piston means is urged in the return direction; and resisting means carried by said housing and engaging said slidable means to resist sliding movement of the latter.
Claim 3
Dependent Claim
40 words
The invention of claim 1: said slidable means being an annular member circumscribing said piston means; said resisting means including an annular seal carried by said housing and slidably and frictionally engaging the outer circumferential surface of said annular member.
Claim 4
Dependent Claim
223 words
In a fluid actuator: a housing defining a compartment therewithin; piston means slidably mounted in said compartment and dividing the latter into a pair of chambers; means for admitting pressurized fluid into one of said chambers to thereby drive said piston means in an actuating direction; resilient means for urging said piston means in a return direction upon release of said pressurized fluid in said one chamber; passage means extending through said piston means to communicate said chambers; slidable means slidably carried on said piston means and shiftable relative to the latter from a first position permitting communication through said passage means to a second position closing said passage means; said slidable means being responsive to movement of said piston means to move from said first position to said second position when movement of said piston in the actuating direction is initiated, remaining in said second position during further movement of said piston means in said actuating direction, shifting from said second position to said first position when movement of the piston means in said return direction is initiated, and remain-ing in said first position during movement of the piston means in said return direction; said slidable means being a sleeve circumscribing said piston means; and an annular seal circumscribing said sleeve and frictionally engaging the sleeve to resist movement of the latter.
Claim 5
Dependent Claim
223 words
In a fluid actuator: a housing defining a compartment therewithin; piston means slidably mounted in said compartment and dividing the latter into a pair of chambers; means for admitting pressurized fluid into one of said chambers to thereby drive said piston means in an actuating direction; resilient means for urging said piston means in a return direction upon release of said pressurized fluid in said one chamber; passage means extending through said piston means to communicate said chambers; slidable means slidably carried on said piston means and shiftable relative to the latter from a first position permitting communication through said passage means to a second position closing said passage means; said slidable means being responsive to movement of said piston means to move from said first position to said second position when movement of said piston in the actuating direction is initiated, remaining in said second position during further movement of said piston means in said actuating direction, shifting from said second position to said first position when movement of the piston means in said return direction is initiated, and remain-ing in said first position during movement of the piston means in said return direction; said slidable means being a sleeve circumscribing said piston means; and an annular seal circumscribing said sleeve and frictionally engaging the sleeve to resist movement of the latter.
References Cited (Backward Citations)
US300401A
Cited
US487132A
Cited
US2742878A
Cited
US2755779A
Cited
US2778339A
Cited
AT200459B
Cited
US3476019A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-02-04 | 1977-08-06 | 1978-02-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-02-04 | 1981-08-06 | 1982-02-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-02-04 | 1985-08-06 | 1986-02-05 | $7700.00 | Window Closed / Lapsed |