Patent US3842949A successfully refreshed from Google Patents.
US3842949A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Disc brakes
Assignee: Girling Ltd
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Filing: 1973-02-02
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Granted: 1974-10-22
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Expires: 1993-02-02
Abstract
Abstract A spring brake actuator for a vehicle wheel disc brake comprises a pad assembly, a strut of adjustable length having a first part fast with a piston of a fluid pressure motor, the piston being spring biassed in a brake-applying direction, and a second part manually adjustable axially relative to the first part between an operative position, in which has thrust transmitting engagement with the pad assembly and holds the first part clear of the assembly, and an inoperative position in which it is released from thrust transmitting engagement with the pad assembly. The first strut part is held clear of the pad assembly either by the application of fluid pressure to the piston or by the engagement of the piston with a mechanical stop under the action of the spring bias.
Inventors
- 👤 C Newstead
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 11:02
CPC Classifications
F; F16; F16D; F16D66/00; F16D66/02; F16D66/021; F16D66/022; F16D66/025; F16D65/00; F16D65/14; F16D65/16; F16D65/18; F16D65/38; F16D65/40; F16D65/52; F16D65/56; F16D65/567; F16D2121/00; F16D2121/02; F16D2121/12; F16D2123/00
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
208 words
In or for a vehicle wheel disc brake having a rotatable disc, a spring brake actuator which comprises a friction pad assembly for frictionally engaging said disc to apply the brake, a thrust transmitting assembly acting on said pad assembly in a brakeapplying direction, and a fluid pressure motor including spring means, a pressure responsive member operable to oppose said spring means and mechanical stop means limiting movement of said pressure responsive member in said brake applying direction, said thrust transmitting assembly comprising a strut of adjustable length having a first part fast with said pressure responsive member, and a second part manually adjustable axially relative to said first part, between an operative position in which said second part has simple abutting engagement with said pad assembly and holds said first part clear of said pad assembly and an inoperative position in which said second part is released from simple abutting engagement with said pad assembly, said first part being held clear of thrust transmitting engagement with said pad assembly either by the application of fluid pressure to said pressure responsive member of said motor, or by engagement of said pressure responsive member of said motor with said mechanical stop means under the action of said spring means.
Claim 2
Dependent Claim
208 words
In or for a vehicle wheel disc brake having a rotatable disc, a spring brake actuator which comprises a friction pad assembly for frictionally engaging said disc to apply the brake, a thrust transmitting assembly acting on said pad assembly in a brakeapplying direction, and a fluid pressure motor including spring means, a pressure responsive member operable to oppose said spring means and mechanical stop means limiting movement of said pressure responsive member in said brake applying direction, said thrust transmitting assembly comprising a strut of adjustable length having a first part fast with said pressure responsive member, and a second part manually adjustable axially relative to said first part, between an operative position in which said second part has simple abutting engagement with said pad assembly and holds said first part clear of said pad assembly and an inoperative position in which said second part is released from simple abutting engagement with said pad assembly, said first part being held clear of thrust transmitting engagement with said pad assembly either by the application of fluid pressure to said pressure responsive member of said motor, or by engagement of said pressure responsive member of said motor with said mechanical stop means under the action of said spring means.
Claim 3
Dependent Claim
34 words
An actuator according to claim 1, wherein said first strut part comprises a tubular sleeve and said second strut part includes an adjuster member extending co-axially within said sleeve and in screw-threaded engagement therewith.
Claim 4
Dependent Claim
63 words
An actuator according to claim 2, wherein said second strut part comprises a transmission member disposed between said adjuster member and said pad assembly and dimensioned and arranged to enter said sleeve in said inoperative position of said adjuster member, said adjuster member bearing on said pad assembly through the intermediary of said transmission member in said operative position of said adjuster member.
Claim 5
Dependent Claim
16 words
An actuator according to claim 3, wherein said transmission member is formed of low friction material.
Claim 6
Dependent Claim
85 words
An actuator according to claim 1, wherein said pad assembly comprises a backing member and a friction pad mounted on the backing member and wherein the permissible movement of said second strut part between said inoperative position, in which it is just released from thrust transmitting engagement with said pad assembly, and position when said strut is of maximum length is approximately equal to twice the maximum thickness of said friction pad less the maximum permissible movement of said pressure responsive member of said motor.
Claim 7
Dependent Claim
34 words
An actuator according to claim 5, wherein said first and second strut parts carry stop means and said permissible movement of said second strut part is limited by the interengagement of said stop means.
Claim 8
Dependent Claim
54 words
An actuator according to claim 1, including a fixed member, wherein said spring means comprises a stack of Belleville washers acting directly between said fixed member and said first strut part, said Belleville washers surrounding both said first and second strut parts and being disposed between said pressure responsive member and said pad assembly.
Claim 9
Dependent Claim
45 words
An actuator according to claim 1, including a fixed member, wherein said spring means comprises a stack of Belleville washers acting between said fixed member and said pressure responsive member and arranged on one side of said pressure responsive member remote from said pad assembly.
Claim 10
Dependent Claim
26 words
An actuator according to claim 1, including means for detecting and indicating excessive movement of said first strut part due to wear of said pad assembly.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-10-21 | 1978-04-22 | 1978-10-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-10-21 | 1982-04-22 | 1982-10-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-10-21 | 1986-04-22 | 1986-10-22 | $7700.00 | Window Closed / Lapsed |