Patent US3640587A successfully refreshed from Google Patents.
US3640587A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Vehicle wheel braking systems
Assignee: Rootes Motors Ltd
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Filing: 1970-03-30
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Granted: 1972-02-08
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Expires: 1990-03-30
Abstract
Abstract A vehicle wheel braking system having a hydraulic pressure operated brake capsule of causing wheel slip, a positive action pump driven in synchronism with the wheel to produce hydraulic pressure for operating the brake and means for varying the braking effect to maintain wheel slip at a substantially constant value or within a predetermined range when maximum braking is required.
Inventors
- 👤 Peter James Milner
- 👤 Richard Keith Hodkin
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 20:32
CPC Classifications
B; B60; B60T; B60T8/00; B60T8/32; B60T8/34; B60T8/40; B60T8/4095
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
148 words
A vehicle wheel braking system comprising a fluid pressure operated brake capable of causing wheel slip, a positive action fluid pump driven by a wheel to be braked and meaNs for varying the braking effect to maintain wheel slip at a substantially constant value comprising means for producing a control pressure which is proportional to vehicle speed and a fluid line along which the volumetric output of the pump which is proportional to actual wheel speed flows, the fluid line containing two restrictions, in series whereby there is produced a pressure downstream of the pump in two parts, a first part upstream of the restrictions being connected to the fluid pressure operated brake and a second part between the restrictions and one of which restrictions is automatically variable to maintain a substantially constant pressure relationship between said control pressure and said second part for any particular vehicle speed.
Claim 2
Dependent Claim
148 words
A vehicle wheel braking system comprising a fluid pressure operated brake capable of causing wheel slip, a positive action fluid pump driven by a wheel to be braked and meaNs for varying the braking effect to maintain wheel slip at a substantially constant value comprising means for producing a control pressure which is proportional to vehicle speed and a fluid line along which the volumetric output of the pump which is proportional to actual wheel speed flows, the fluid line containing two restrictions, in series whereby there is produced a pressure downstream of the pump in two parts, a first part upstream of the restrictions being connected to the fluid pressure operated brake and a second part between the restrictions and one of which restrictions is automatically variable to maintain a substantially constant pressure relationship between said control pressure and said second part for any particular vehicle speed.
Claim 3
Dependent Claim
21 words
A vehicle braking system as claimed in claim 1 wherein the upstream restriction is varied in accordance with the control pressure.
Claim 4
Dependent Claim
25 words
A vehicle braking system as claimed in claim 1 or claim 2 wherein the outlet side of the downstream restriction is at substantially atmospheric pressure.
Claim 5
Dependent Claim
30 words
A vehicle braking system as claimed in claim 1 wherein the control pressure is derived from a pump driven by another wheel which is unbraked, lightly braked or intermittently braked.
Claim 6
Dependent Claim
38 words
A vehicle braking system as claimed in claim 1 wherein the means for producing the control pressure include a radar device which determines vehicle speed and which controls a source of fluid pressure in accordance with vehicle speed.
Claim 7
Dependent Claim
50 words
A vehicle braking system as claimed in claim 1 wherein the means for producing the control pressure comprise a further fluid line connected to the first fluid line and which further line is opened by pressure pulses in the first line which occur during excessive slip of the braked wheel.
Claim 8
Dependent Claim
29 words
A vehicle braking system as claimed in claim 6 wherein said further line contains a nonreturn valve which is opened by a pressure pulse in the first fluid line.
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) | 1975-02-07 | 1975-08-09 | 1976-02-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-02-07 | 1979-08-09 | 1980-02-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-02-07 | 1983-08-09 | 1984-02-08 | $7700.00 | Window Closed / Lapsed |