US3918767A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Antiskid vehicle brake system for individual wheel control including a fluid pressure comparator device
Assignee: Wabco Westinghouse GmbH Germany
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Filing: 1974-04-04
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Granted: 1975-11-11
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Expires: 1994-04-04
Abstract
Abstract An electronic antiskid brake control system for effecting adjustment of brake pressure on the individual wheels of a common axle of a vehicle independent of the operator controlled brake pressure in such a manner that when a predetermined brake pressure difference arises between the respective wheels, due to the skidding of one wheel, the higher wheel brake pressure is adjusted so as to prevent the brake pressure difference from exceeding the predetermined difference. In one embodiment, a control piston subject to the different wheel brake pressures operates a switch armature between a pair of electrical contacts via which one or the other of modulating valves in the respective wheel brake lines is energized when the predetermined brake pressure difference arises. In a second embodiment, a pressure limiting valve subject to the different wheel brake pressures is connected in each brake line between the modulating valve and brake cylinder to adjust the brake pressure of that wheel when the other wheel brake pressure is greater by the predetermined brake pressure difference. Until this predetermined brake pressure difference develops, the non-skidding wheel in each of the above embodiments produces normal braking to obtain good stop distances, while steering stability is maintained by limiting the brake pressure difference in excess of that which is considered unsafe.
Inventors
- 👤 Erich Reinecke
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 04:06
CPC Classifications
B; B60; B60T; B60T8/00; B60T8/32; B60T8/34; B60T8/341; B60T8/342; B60T8/343
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
162 words
An antiskid brake control system for a vehicle having a pair of independently rotatable wheels on a common axle of the vehicle, said system comprising: a. a fluid pressure actuated brake device for each of said wheels; b. an operator controlled foot valve device via which the brake actuating fluid pressure is selectively controlled; c. a brake line connecting said foot valve device with each wheel brake device to convey the brake actuating fluid pressure thereto; d. modulator valve means in each said brake line for modulating the fluid brake pressure at said brake device connected therewith; and e. evaluation means for each of said wheels operative responsive to a particular dynamic condition thereof for effecting operation of said modulator valve means of a respective wheel, wherein the improvement comprises; f. means for comparing the fluid brake pressure effective at said brake device of each said wheel so as to influence the higher fluid brake pressure when a predetermined difference arises therebetween.
Claim 2
Dependent Claim
162 words
An antiskid brake control system for a vehicle having a pair of independently rotatable wheels on a common axle of the vehicle, said system comprising: a. a fluid pressure actuated brake device for each of said wheels; b. an operator controlled foot valve device via which the brake actuating fluid pressure is selectively controlled; c. a brake line connecting said foot valve device with each wheel brake device to convey the brake actuating fluid pressure thereto; d. modulator valve means in each said brake line for modulating the fluid brake pressure at said brake device connected therewith; and e. evaluation means for each of said wheels operative responsive to a particular dynamic condition thereof for effecting operation of said modulator valve means of a respective wheel, wherein the improvement comprises; f. means for comparing the fluid brake pressure effective at said brake device of each said wheel so as to influence the higher fluid brake pressure when a predetermined difference arises therebetween.
Claim 3
Dependent Claim
35 words
The system as recited in claim 1, further characterized in that the higher wheel brake pressure is influenced in such sense as to prevent the respective wheel brake pressure differential from exceeding said predetermined difference.
Claim 4
Dependent Claim
113 words
The system as recited in claim 2, further characterized in that said means for comparing the respective wheel brake pressures is a differential pressure switch comprising: a. a pair of electrical switch contacts; b. an actuator piston subject on opposite sides thereof to said respective wheel brake pressures; c. spring means for biasing said actuating piston in a neutral position; and d. a switch armature carried by said actuating piston for engagement with one or the other of said switch contacts when said piston is moved in either direction from said neutral position to energize and thereby effect said operation of the modulator valve means of whichever wheel exhibits the higher brake pressure.
Claim 5
Dependent Claim
55 words
The system as recited in claim 3, further characterized in that said spring means loads said piston an amount corresponding to said predetermined difference between said wheel brake pressures to prevent energization of the modulator valve means associated with the higher wheel brake pressure until said brake pressure differential between the respective wheels is exceeded.
Claim 6
Dependent Claim
183 words
The system as recited in claim 1, further characterized in that said means for comparing the respective wheel brake pressures is a differential pressure limiting device disposed in the brake line of each wheel intermediate the modulator valve means and the brake cylinder of that wheel, each pressure limiting device comprising: a. piston valve means for controlling the brake pressure of one of the wheels in accordance with actuation to a first position in which fluid pressure communication is established between the one wheel brake cylinder and modulator valve means in response to loading of said piston valve means by the brake pressure of the other wheel and to a second position in which the one wheel brake pressure is reduced in response to loading of said piston valve means by the brake pressure of the one wheel; and b. bias means for loading said piston valve means toward said first position so as to delay actuation of said piston valve means from said first position to said second position until the one wheel brake pressure exceeds the other by said predetermined difference.
Claim 7
Dependent Claim
153 words
The system recited in claim 5, wherein said piston valve means comprises: a. a piston member having its opposite faces subject to the respective wheel brake pressures and including an extension arm on which is formed an exhaust valve seat; and b. a valve member separate from said piston member and having a through passage to atmosphere, said valve member in said first position being engageable with said exhaust valve seat to interrupt fluid pressure communication between said through passage and the one wheel brake cylinder and disengaged from a supply valve seat to establish fluid pressure communication between the one wheel modulator valve means and brake cylinder, and in said second position being engageable with said supply valve seat to interrupt fluid pressure communication between the one wheel modulator valve means and brake cylinder and disengaged from said exhaust valve seat to communicate said through passage with the one wheel brake cylinder.
Claim 8
Dependent Claim
62 words
The system recited in claim 6, further characterized in that said piston member in an intermediate position between said first and second positions cooperates with said valve member such that said supply and exhaust valve seats are concurrently engaged by said valve member to interrupt fluid pressure communication between the brake cylinder and both the modulator valve means and said through passage.
Claim 9
Dependent Claim
15 words
The system recited in claim 5, wherein said bias means is comprised of a spring.
Claim 10
Dependent Claim
81 words
The system recited in claim 8, further characterized in that said piston valve means is operative responsive to the respective wheel brake pressures effective in first and second chambers in which said piston valve means operates, said spring being disposed in a fluid pressure isolated third chamber into which an arm of said piston valve means extends for engagement with said spring to establish said spring load in accordance with which said piston valve means is biased toward said first position.
Claim 11
Dependent Claim
24 words
The system recited in claim 5, wherein said bias means is comprised of said piston valve means in the form of a differential piston.
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) | 1978-11-10 | 1979-05-12 | 1979-11-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-11-10 | 1983-05-12 | 1983-11-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-11-10 | 1987-05-12 | 1987-11-11 | $7700.00 | Window Closed / Lapsed |