Patent US3922857A successfully refreshed from Google Patents.
US3922857A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Vehicle dual braking systems
Assignee: Girling Ltd
•
Filing: 1973-11-02
•
Granted: 1975-12-02
•
Expires: 1993-11-02
Abstract
Abstract A pressure generating device for a vehicle braking system comprises pressure generating members, preferably pistons of a tandem master cylinder, and pressure chambers, preferably chambers of a master cylinder, one of which is connected through a control valve to a vehicle brake. An operating valve is provided which is directly and positively actuated in response to predetermined excess movement of one of the members, upon a pressure failure in one of the chambers, to pass the full pressure of the other chamber to the wheel brake, rendering the control valve effectively inoperative.
Inventors
- 👤 Michael Albert Carey
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 19:00
CPC Classifications
B; B60; B60T; B60T11/00; B60T11/10; B60T11/28; B60T11/34; B60T11/16; B60T11/20; B60T8/00; B60T8/26
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
131 words
In a vehicle braking system comprising a master cylinder having primary and secondary pressure chambers and primary and secondary pistons slidable in said chambers, mechanical actuating means for effecting movement of said primary and secondary pistons to generate pressure in the respective chambers, first and second fluid pressure operated brakes operatively connected to the respective primary and secondary pressure chambers, a fluid pressure proportioning valve between said primary pressure chamber and the brake operatively connected thereto, disabling means for disabling the proportioning effects of said proportioning valve, and means in said master cylinder for directly and positively operating said disabling means by the secondary piston upon predetermined excess movemeNt thereof in response to loss of fluid pressure in the secondary pressure chamber following operation of said pistons to apply said brakes.
Claim 2
Dependent Claim
131 words
In a vehicle braking system comprising a master cylinder having primary and secondary pressure chambers and primary and secondary pistons slidable in said chambers, mechanical actuating means for effecting movement of said primary and secondary pistons to generate pressure in the respective chambers, first and second fluid pressure operated brakes operatively connected to the respective primary and secondary pressure chambers, a fluid pressure proportioning valve between said primary pressure chamber and the brake operatively connected thereto, disabling means for disabling the proportioning effects of said proportioning valve, and means in said master cylinder for directly and positively operating said disabling means by the secondary piston upon predetermined excess movemeNt thereof in response to loss of fluid pressure in the secondary pressure chamber following operation of said pistons to apply said brakes.
Claim 3
Dependent Claim
74 words
In the system according to claim 1 wherein the disabling means comprises a port in said master cylinder connected to one of said wheel brakes, and the means in said master cylinder for operating said disabling means comprises said secondary system cooperating with said port to define a normally closed valve which is opened by said predetermined excess movement of said secondary piston to admit pressure from said primary chamber to said wheel brake.
Claim 4
Dependent Claim
65 words
In the system according to claim 1 wherein said disabling means comprises a further normally closed valve provided externally of said master cylinder, said operating means in said master cylinder comprising a valve stem on said further valve and extending into said master cylinder, said stem being engageable by said secondary piston to open said valve upon said predetermined excess movement of said secondary piston.
Claim 5
Dependent Claim
65 words
In the system of claim 3 wherein said stem extends into said master cylinder intermediate the ends thereof, and wherein said secondary piston includes a recess having aubtment means therein, said valve stem in normal operation extending into said recess clear of said abutment means but being engaged by said abutment means to open said valve upon said predetermined excess movement of said secondary piston.
Claim 6
Dependent Claim
41 words
In the system according to claim 3 wherein said valve stem extends into the secondary chamber of said master cylinder and is directly engageable by said secondary piston upon predetermined excess movement thereof following loss of pressure in said secondary chamber.
Claim 7
Dependent Claim
43 words
In the system according to claim 4, wherein said primary chamber constitutes said source and said valve stem extends into said secondary chamber and is engageable by said secondary piston upon predetermined excess movement thereof following loss of pressure in said secondary chamber.
Claim 8
Dependent Claim
47 words
In the system according to claim 6, wherein said master cylinder has an end wall which constitutes a wall of said secondary chamber, and wherein said valve stem extends through said wall, whereby it is engageable by said secondary piston as the latter bottoms in said cylinder.
References Cited (Backward Citations)
US3701567A
Cited
US3661426A
Cited
US3674954A
Cited
US3686864A
Cited
US3774973A
Cited
US3727989A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-12-01 | 1979-06-02 | 1979-12-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-12-01 | 1983-06-02 | 1983-12-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-12-01 | 1987-06-02 | 1987-12-02 | $7700.00 | Window Closed / Lapsed |