Patent US3861756A successfully refreshed from Google Patents.
US3861756A
Expired / Lapsed
US
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Anti-skid system for vehicles
Assignee: Nabco Ltd
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Filing: 1973-08-20
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Granted: 1975-01-21
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Expires: 1993-08-20
Abstract
Abstract An anti-skid system for vehicles comprising a wheel speed detector, a generator for generating an approximate vehicle body speed pattern when the wheel deceleration attains a first reference setting, a first comparator for comparing the wheel speed with the approximate vehicle body speed pattern, a differentiator for differentiatng the wheel speed, a second comparator for comparing the differentiator output with a second reference setting, a third comparator for comparing the differentiator output with a third reference setting, apparatus for changing over the level of the first, second and third reference settings depending on the road surface condition, and two solenoid operated valves whose solenoids are electrically connected to the comparators through AND gates for controlling the brake fluid pressure applied to the wheel cylinders.
Inventors
- 👤 Tetsuro Arikawa
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 18:23
CPC Classifications
B; B60; B60T; B60T8/00; B60T8/17; B60T8/176; B60T8/1763; B60T8/17633; B60T8/32; B60T8/72
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
275 words
An anti-skid system for vehicles comprising means for detecting the rotating speed of a wheel, means for generating an approximate vehicle body speed pattern signal when the rate of reduction of the wheel speed responsive output of said wheel speed detecting means reaches the level of a first reference setting due to the application of the brake, first comparing means for comparing the wheel speed responsive output of said wheel speed detecting means with the approximate vehicle body speed pattern signal thereby generating a first control signal depending on the relation therebetween, means for differentiating the wheel speed responsive output of said wheel speed detecting means thereby producing a signal representative of the wheel acceleration, second comparing means for comparing the output of said differentiating means with a second reference setting representative of a predetermined deceleration thereby generating a second control signal depending on the relation therebetween, third comparing means for comparing the output of said differentiating means with a third reference setting representative of a predetermined acceleration thereby generating a third control signal depending on the relation therebetween, and switch means responsive to vehicle body deceleration for setting said first, second and third settings to one of two levels depending on the road surface condition, said first and third comparing means being connected through an AND gate to the solenoid of a solenoid operated valve in a modulator, said first and second comparing means being connected through another AND gate to the solenoid of another solenoid operated valve in said modulator so as to selectively energize and de-energize the solenoids of said solenoid operated valves thereby relieving, maintaining and increasing the brake fluid pressure.
Claim 2
Dependent Claim
275 words
An anti-skid system for vehicles comprising means for detecting the rotating speed of a wheel, means for generating an approximate vehicle body speed pattern signal when the rate of reduction of the wheel speed responsive output of said wheel speed detecting means reaches the level of a first reference setting due to the application of the brake, first comparing means for comparing the wheel speed responsive output of said wheel speed detecting means with the approximate vehicle body speed pattern signal thereby generating a first control signal depending on the relation therebetween, means for differentiating the wheel speed responsive output of said wheel speed detecting means thereby producing a signal representative of the wheel acceleration, second comparing means for comparing the output of said differentiating means with a second reference setting representative of a predetermined deceleration thereby generating a second control signal depending on the relation therebetween, third comparing means for comparing the output of said differentiating means with a third reference setting representative of a predetermined acceleration thereby generating a third control signal depending on the relation therebetween, and switch means responsive to vehicle body deceleration for setting said first, second and third settings to one of two levels depending on the road surface condition, said first and third comparing means being connected through an AND gate to the solenoid of a solenoid operated valve in a modulator, said first and second comparing means being connected through another AND gate to the solenoid of another solenoid operated valve in said modulator so as to selectively energize and de-energize the solenoids of said solenoid operated valves thereby relieving, maintaining and increasing the brake fluid pressure.
Claim 3
Dependent Claim
76 words
An anti-skid system as claimed in claim 1, wherein said first and second reference settings are set to a higher level and said third reference setting is set to a lower level when the vehicle runs on a high friction road surface, while said first and second reference settings are set to a lower level and said third reference setting is set to a higher level when the vehicle runs on a low friction road surface.
Claim 4
Dependent Claim
55 words
Apparatus as claimed in claim 1 wherein said means for obtaining said first control signal includes means for comparing the rate of decrease of wheel speed to a predetermined rate of decrease and for generating a signal representing said approximate vehicle body speed when said rate of decrease of wheel speed equals said predetermined rate.
Claim 5
Dependent Claim
41 words
Apparatus according to claim 1 wherein the approximate vehicle body speed pattern signal, when initiated, is equal to the wheel speed responsive output of the wheel speed detecting means and thereafter said pattern signal is reduced at a predetermined constant rate.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-01-20 | 1978-07-22 | 1979-01-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-01-20 | 1982-07-22 | 1983-01-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-01-20 | 1986-07-22 | 1987-01-21 | $7700.00 | Window Closed / Lapsed |