US3729931A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Boosted hydraulic systems
Assignee: Wabco Automotive UK Ltd
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Filing: 1970-12-14
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Granted: 1973-05-01
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Expires: 1990-12-14
Abstract
Abstract A boosted hydraulic system for brake, clutch or similar actuation and adapted to actuate two independent load circuits comprises a manually-operable master cylinder, valve means actuated hydraulically or mechanically by movement of the master cylinder piston and controlling flow of pressurized fluid to a servo device and to one load circuit, and a supplementary hydraulic cylinder actuated mechanically by the piston of the servo device and the output of which actuates the second load circuit, the fluid delivered by the master cylinder also acting on the piston of the supplementary hydraulic cylinder but, in the event of failure of the servo device, by-passing said piston to flow directly to said second load circuit.
Inventors
- 👤 B Shilton
- 👤 D Byron
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 21:05
CPC Classifications
B; B60; B60T; B60T13/00; B60T13/10; B60T13/12; B60T13/14; B60T13/142; B60T13/145; B60T13/146
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
216 words
A dual hydraulic system for vehicle brake actuation comprising two sets of brakes and a separate hydraulic operating circuit for each set of brakes, means providing a full power hydraulic pressure source, a manually operable master cylinder adapted to generate hydraulic pressure independently of said source when operated, a supplementary hydraulic cylinder connected to one of said circuits for actuating one set of brakes and having a piston therein, a servo device adapted to control said piston, means including valve means connected to be operated by the hydraulic pressure generated when said master cylinder is operated to apply the brakes for operably connecting said hydraulic pressure source to the other of said circuits to actuate the other set of brakes and to also actuate said servo device to displace said supplementary piston to actuate said one set of brakes, by-pass means for supplying hydraulic pressure generated by the master cylinder directly to said one circuit in the event that there is insufficient hydraulic pressure applied to said servo device when said master cylinder is operated to apply the brakes, said by-pass means comprising a passage extending through said suppleMentary piston to said one circuit and seal means operable in response to normal actuation of said servo device by said hydraulic pressure source to close said passage.
Claim 2
Dependent Claim
216 words
A dual hydraulic system for vehicle brake actuation comprising two sets of brakes and a separate hydraulic operating circuit for each set of brakes, means providing a full power hydraulic pressure source, a manually operable master cylinder adapted to generate hydraulic pressure independently of said source when operated, a supplementary hydraulic cylinder connected to one of said circuits for actuating one set of brakes and having a piston therein, a servo device adapted to control said piston, means including valve means connected to be operated by the hydraulic pressure generated when said master cylinder is operated to apply the brakes for operably connecting said hydraulic pressure source to the other of said circuits to actuate the other set of brakes and to also actuate said servo device to displace said supplementary piston to actuate said one set of brakes, by-pass means for supplying hydraulic pressure generated by the master cylinder directly to said one circuit in the event that there is insufficient hydraulic pressure applied to said servo device when said master cylinder is operated to apply the brakes, said by-pass means comprising a passage extending through said suppleMentary piston to said one circuit and seal means operable in response to normal actuation of said servo device by said hydraulic pressure source to close said passage.
Claim 3
Dependent Claim
34 words
The dual hydraulic system defined in claim 1, wherein means is provided for applying master cylinder generated pressure to said supplementary piston while said servo device is being actuated to displace said supplementary piston.
Claim 4
Dependent Claim
47 words
The dual hydraulic system defined in claim 1, wherein said master cylinder contains a movable hydraulic pressure generating piston and said valve means includes actuating means adapted to be positively operated by said master cylinder piston in the event of failure of master cylinder generated hydraulic pressure.
Claim 5
Dependent Claim
70 words
The dual hydraulic system defined in claim 1, wherein said master cylinder contains a movable hydraulic pressure generating piston and said valve means includes valve actuating means having a slidably mounted abutment adjacent said master cylinder piston and preload spring means disposed between said master cylinder piston and said abutment, whereby initial displacement of said master cylinder piston in the brake applying direction will positively actuate said valve actuating means.
Claim 6
Dependent Claim
55 words
The dual hydraulic system defined in claim 1, wherein said valve means comprises a seating element disposed in a passage connected to said source, and a control piston slidably mounted with respect to said seating element and operated in response to operation of said master cylinder to engage said element to open said valve means.
Claim 7
Dependent Claim
25 words
The dual hydraulic system defined in claim 5, wherein positive abutment means are provided on the master cylinder and control pistons for positive valve operation.
Claim 8
Dependent Claim
102 words
A dual hydraulic system as recited in claim 1, wherein said servo device includes a piston slidable with respect to the piston of the supplementary hydraulic cylinder and having an end adapted to engage and displace the piston of the supplementary hydraulic cylinder, said seal means being provided on said end of said servo piston to seal off said by-pass passage when said servo piston is engaging and displacing said supplementary cylinder piston, the hydraulic pressure generated by said master cylinder acting on an annular face of said supplementary cylinder piston surrounding the region engaged by said end of said servo piston.
Claim 9
Dependent Claim
66 words
A dual hydraulic system as recited in claim 1, wherein the servo device includes a piston which together with the piston of the supplementary hydraulic cylinder forms a dual piston structure, said by-pass passage extending through said dual piston structure, and said seal means including a valve for controlling said by-pass passage adapted to close automatically when said piston structure moves away from ''''brakes off'''' position.
Claim 10
Dependent Claim
123 words
A dual hydraulic system as claimed in claim 1, wherein the servo device includes a piston which together with the piston of the supplementary hydraulic cylinder forms a dual piston structure having an enlarged head, pressurized fluid of the servo system being directed to the rear face of said enlarged head whilst fluid displaced by the master cylinder is conducted to the front end of said supplementary hydraulic cylinder by way of said by-pass passage which extends through the dual piston structure, and said seal means including valve means co-acting with an end wall of said supplementary hydraulic cylinder and operable to close off said passage as soon as the dual piston structure moves under servo power away from the ''''brakes off'''' position.
Claim 11
Dependent Claim
100 words
A boosted hydraulic system as claimed in claim 1, wherein the servo device includes a piston which together with the piston of the secondary hydraulic cylinder forms a dual piston structure, said piston structure being hollow and providing said by-pass passage at one point by which fluid from the master cylinder is delivered to the secondary hydraulic cylinder ahead of the piston structure, and said piston structure accommodating said seal means including a tappet valve element responsive to the pressure developed in the servo system and co-acting with a seating in the piston structure to close off said by-pass passage.
References Cited (Backward Citations)
US2862364A
Cited
US3183670A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-04-30 | 1976-10-30 | 1977-05-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-04-30 | 1980-10-30 | 1981-05-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-04-30 | 1984-10-30 | 1985-05-01 | $7700.00 | Window Closed / Lapsed |