Patent US3858488A successfully refreshed from Google Patents.
US3858488A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Vehicle brake actuators
Assignee: Grau Ltd
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Filing: 1972-07-28
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Granted: 1975-01-07
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Expires: 1992-07-28
Abstract
Abstract A vehicle brake actuator comprises an output member which is subject to the action of a first piston working in a cylinder which is pressurised to apply the brake and the biasing force of a spring. A second piston works independently of the first piston in a second cylinder which is normally pressurised to relieve the output member of the spring biasing force. The first piston and the spring are arranged to act on the output member independently of and in parallel with each other.
Inventors
- 👤 Charles Newstead
- 👤 Andrew Charles Walden Wright
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 08:19
CPC Classifications
F; F16; F16D; F16D65/00; F16D65/14; F16D65/28; F16D65/16; F16D65/22; F16D2121/00; F16D2121/02; F16D2121/12; F16D2123/00
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
139 words
An actuator for a vehicle brake comprising an output member moveable between brake applied and released positions, resilient means operatively connected to said output member and biasing it towards its brake applied position, a first fluid operable member working in a working chamber of a first cylinder and operatively connected to said output member parallel with but independently of said resilient means to move said output member to its brake applied position in response to fluid pressure in said first cylinder, a second fluid operable member working in a working chamber of a normally pressurized second cylinder and operatively connected to said resilient means to relieve said output member of the biasing force of said resilient means, and a common, fixed, solid partition wall separating said working chamber of said first and second cylinders and preventing fluid communication therebetween.
Claim 2
Dependent Claim
139 words
An actuator for a vehicle brake comprising an output member moveable between brake applied and released positions, resilient means operatively connected to said output member and biasing it towards its brake applied position, a first fluid operable member working in a working chamber of a first cylinder and operatively connected to said output member parallel with but independently of said resilient means to move said output member to its brake applied position in response to fluid pressure in said first cylinder, a second fluid operable member working in a working chamber of a normally pressurized second cylinder and operatively connected to said resilient means to relieve said output member of the biasing force of said resilient means, and a common, fixed, solid partition wall separating said working chamber of said first and second cylinders and preventing fluid communication therebetween.
Claim 3
Dependent Claim
41 words
An actuator according to claim 1, wherein the operative connection between said first fluid operable member and said output member is a simple abutting engagement so as to enable said output member to move independently of said first fluid operable member.
Claim 4
Dependent Claim
32 words
An actuator according to claim 1, wherein said resilient means comprises a coil compression spring, said first and second fluid pressure operable members and cylinders being wholly contained within said coil spring.
Claim 5
Dependent Claim
62 words
An actuator according to claim 1, including an inner housing comprising one end member arranged to abut said output member, another end member arranged to abut said second fluid operable member, and an intermediate member connected to said end members, and means operatively connecting said inner housing and said resilient means so that the biasing force thereof acts on said inner housing.
Claim 6
Dependent Claim
57 words
An actuator according to claim 4, including hold-off means for manually preventing said spring means from applying the brake, wherein said hold-off means comprises a manually axially movable member arranged to engage said other end member of said inner housing and move said inner housing axially to relieve said output member of said resilient means biasing force.
Claim 7
Dependent Claim
43 words
An actuator according to claim 1, including a main body portion, the working chambers of said first and second cylinders being constituted by oppositely directed blind bores formed in said body portion and defining therebetween a common solid partition wall separating said bores.
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) | 1978-01-06 | 1978-07-08 | 1979-01-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-01-06 | 1982-07-08 | 1983-01-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-01-06 | 1986-07-08 | 1987-01-07 | $7700.00 | Window Closed / Lapsed |