US3810682A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Anti-lock brake system
Assignee: Motors Liquidation Co
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Filing: 1973-03-12
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Granted: 1974-05-14
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Expires: 1993-03-12
Abstract
Abstract An anti-lock brake system utilizes automatic transmission governor pressure as the average rear wheel speed input signal. A check valve communicates fluid from the governor to an accumulator where it is stored. A flow control valve discharges fluid from the accumulator at a constant rate providing a pressure rate or change in the accumulator somewhat exceeding the pressure rate or change or the governor pressure during vehicle deceleration at the maximum achievable rate. The pressure differential resulting between the accumulator pressure and the wheel speed pressure from the governor during periods of excessive wheel deceleration operates a control valve which exhausts the support pressure from a conventional brake pressure modulator to release the brakes. A period of wheel acceleration follows the brake release and during the resulting wheel speed recovery, the accumulator is recharged and the control valve is shifted to reapply support pressure to the modulator. An acceleration sensing circuit is provided which senses the rapid wheel speed recovery subsequent to brake release on a high coefficient surface and reapplies support pressure to the modulator even before the control valve is restored to its normal position so as to hasten the application of the brakes and thereby compensate for the inherent time delay in cycling of the control valve and modulator.
Inventors
- 👤 T Demers
- 👤 E Koivunen
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 20:34
CPC Classifications
B; B60; B60T; B60T8/00; B60T8/32; B60T8/34; B60T8/42; B60T8/4208; B60T8/4225
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
174 words
An anti-lock brake system comprising, a brake pressure modulating means effective to modulate brake pressure communicated to a wheel brake as a function of a control pressure communicated to the brake pressure modulating means, means providing fluid at a pressure proportional to the speed of the wheel and a pressure rate of change proportional to wheel acceleration and deceleration, hydraulic means providing a reference pressure during periods of excessive wheel slip, hydraulic means responsive to the differential between the wheel speed proportional pressure and the reference pressure to vary the control pressure communicated to the brake pressure modulator to cause release of the brake pressure when the pressure differential exceeds a predetermined level and to increase the brake pressure when the differential falls below the predetermined level, and hydraulic means responsive to a predetermined pressure rate of change of the wheel speed proportional pressure for varying the control pressure in the brake pressure modulating means to initiate brake pressure reapplication irrespective of the differential between the wheel speed proportional pressure and the reference pressure.
Claim 2
Dependent Claim
174 words
An anti-lock brake system comprising, a brake pressure modulating means effective to modulate brake pressure communicated to a wheel brake as a function of a control pressure communicated to the brake pressure modulating means, means providing fluid at a pressure proportional to the speed of the wheel and a pressure rate of change proportional to wheel acceleration and deceleration, hydraulic means providing a reference pressure during periods of excessive wheel slip, hydraulic means responsive to the differential between the wheel speed proportional pressure and the reference pressure to vary the control pressure communicated to the brake pressure modulator to cause release of the brake pressure when the pressure differential exceeds a predetermined level and to increase the brake pressure when the differential falls below the predetermined level, and hydraulic means responsive to a predetermined pressure rate of change of the wheel speed proportional pressure for varying the control pressure in the brake pressure modulating means to initiate brake pressure reapplication irrespective of the differential between the wheel speed proportional pressure and the reference pressure.
Claim 3
Dependent Claim
206 words
In a vehicle anti-lock brake system having brake pressure modulating means acting to cyclically release and reapply the brake pressure as a function of a control pressure communicated thereto and hydraulic wheel condition sensing and control logic means for providing the control pressure and including means providing fluid at a pressure proportional to the speed of the braked wheel and at a pressure rate of change to the acceleration and deceleration of the braked wheel, and means for hastening reapplication of brake pressure when wheel acceleration exceeds a predetermined level so as to compensate for inherent time delays in the anti-lock system, said means comprising, an accumulator, orifice means commUnicating wheel speed proportional pressure fluid to the accumulator to charge the accumulator during wheel acceleration and provide a differential between the accumulator pressure and wheel speed proportional pressure when the wheel acceleration causes a flow rate in excess of the flow threshold of the orifice, and valve means operable by a predetermined differential between the wheel speed proportional pressure and the accumulator pressure to vary the control pressure to the brake pressure modulating means to increase the brake pressure irrespective of the control pressure communicated thereto by the hydraulic wheel condition sensing and control logic means.
Claim 4
Dependent Claim
206 words
In a vehicle anti-lock brake system having brake pressure modulating means acting to cyclically release and reapply the brake pressure as a function of a control pressure communicated thereto and hydraulic wheel condition sensing and control logic means for providing the control pressure and including means providing fluid at a pressure proportional to the speed of the braked wheel and at a pressure rate of change to the acceleration and deceleration of the braked wheel, and means for hastening reapplication of brake pressure when wheel acceleration exceeds a predetermined level so as to compensate for inherent time delays in the anti-lock system, said means comprising, an accumulator, orifice means commUnicating wheel speed proportional pressure fluid to the accumulator to charge the accumulator during wheel acceleration and provide a differential between the accumulator pressure and wheel speed proportional pressure when the wheel acceleration causes a flow rate in excess of the flow threshold of the orifice, and valve means operable by a predetermined differential between the wheel speed proportional pressure and the accumulator pressure to vary the control pressure to the brake pressure modulating means to increase the brake pressure irrespective of the control pressure communicated thereto by the hydraulic wheel condition sensing and control logic means.
Claim 5
Dependent Claim
286 words
An anti-lock brake system comprising, a brake pressure modulating means operable to selectively release and reapply the brake pressure to a wheel brake, governor means driven at wheel speed and providing fluid at a pressure proportional to wheel speed and a pressure rate of change proportional to the wheel acceleration and deceleration, a first accumulator, check valve means communicating wheel speed proportional pressure fluid to the first accumulator to charge the first accumulator, flow control valve means discharging pressure fluid from the first accumulator at a maximum rate and providing a differential between the wheel speed proportional pressure and the first accumulator pressure during wheel deceleration causing a pressure rate of change through the governor means exceeding the pressure rate of change through the flow control valve, control valve means operable by the differential between wheel speed proportional and first accumulator pressure to operate the brake pressure modulating means to release the brake pressure when the differential exceeds a predetermined level and to increase the brake pressure when increasing wheel speed subsequent to brake pressure release causes the differential pressure to fall below a predetermined level, a second accumulator, orifice means communicating wheel speed proportional pressure fluid to the second accumulator to charge the second accumulator during wheel acceleration and provide a differential between the second accumulator pressure and wheel speed proportional pressure when the wheel acceleration causes a flow rate in excess of the flow threshold of the orifice, and valve means operable by a predetermined differential between the wheel speed proportional pressure and the second accumulator pressure to operate the brake pressure modulating means to increase the brake pressure irrespective of the differential between the wheel speed proportional pressure and the first accumulator pressure.
Claim 6
Dependent Claim
286 words
An anti-lock brake system comprising, a brake pressure modulating means operable to selectively release and reapply the brake pressure to a wheel brake, governor means driven at wheel speed and providing fluid at a pressure proportional to wheel speed and a pressure rate of change proportional to the wheel acceleration and deceleration, a first accumulator, check valve means communicating wheel speed proportional pressure fluid to the first accumulator to charge the first accumulator, flow control valve means discharging pressure fluid from the first accumulator at a maximum rate and providing a differential between the wheel speed proportional pressure and the first accumulator pressure during wheel deceleration causing a pressure rate of change through the governor means exceeding the pressure rate of change through the flow control valve, control valve means operable by the differential between wheel speed proportional and first accumulator pressure to operate the brake pressure modulating means to release the brake pressure when the differential exceeds a predetermined level and to increase the brake pressure when increasing wheel speed subsequent to brake pressure release causes the differential pressure to fall below a predetermined level, a second accumulator, orifice means communicating wheel speed proportional pressure fluid to the second accumulator to charge the second accumulator during wheel acceleration and provide a differential between the second accumulator pressure and wheel speed proportional pressure when the wheel acceleration causes a flow rate in excess of the flow threshold of the orifice, and valve means operable by a predetermined differential between the wheel speed proportional pressure and the second accumulator pressure to operate the brake pressure modulating means to increase the brake pressure irrespective of the differential between the wheel speed proportional pressure and the first accumulator pressure.
References Cited (Backward Citations)
US3672731A
Cited
US3718375A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-05-13 | 1977-11-12 | 1978-05-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-05-13 | 1981-11-12 | 1982-05-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-05-13 | 1985-11-12 | 1986-05-14 | $7700.00 | Window Closed / Lapsed |