US3661428A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Electrical circuit arrangements for converting a variable rate of pulse transmission into a related electrical output quantity
Assignee: US Philips Corp
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Filing: 1969-09-16
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Granted: 1972-05-09
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Expires: 1989-09-16
Abstract
Abstract An anti-lock vehicle brake control system comprising a wheel sensor for generating a train of pulses at a frequency proportional to the wheel speed. A switching transistor receives the pulses. A first capacitor is coupled to the output of the switching transistor via a first isolation diode. The switching transistor causes the first capacitor to charge up to a predetermined voltage level for each pulse received. A discharge circuit allows the first capacitor to discharge in the interval between successive pulses. A second capacitor is permanently connected to a source of charging current and is also coupled to the first capacitor via a second isolation diode so that the second capacitor will discharge towards the voltage level on the first capacitor to produce a voltage on the second capacitor that is proportional to wheel speed. The latter voltage is used to actuate a control valve in the vehicle brake fluid pressure system to relieve the braking pressure whenever said capacitor voltage exceeds a given value.
Inventors
- 👤 Denis Sharp
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 12:09
CPC Classifications
B; B60; B60T; B60T8/00; B60T8/32; B60T8/321; B60T8/3235; B60T8/324; B60T8/17; B60T8/172; B60T8/58; B60T8/72; G; G01; G01R; G01R23/00; G01R23/02; G01R23/06; G01R23/09; H; H03; H03K; H03K9/00; H03K9/06
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
206 words
An anti-lock vehicle brake control system comprising, a source of Fluid pressure to control the braking force on a vehicle wheel, a wheel sensor for producing a train of pulses at a frequency that is related to the vehicle wheel speed, transistor switching means coupled to said wheel sensor to receive said pulse train, a first isolating diode, a first capacitor coupled to said transistor switching means via said first diode, said transistor switching means being responsive to the pulses in said pulse train to cause said first capacitor to be charged to a predetermined voltage level via said first diode, circuit means for discharging said first capacitor during the period between successive pulses in the pulse train, a second capacitor, a charge circuit including a source of voltage permanently connected to said second capacitor, a second isolating diode coupling said first and second capacitors together so that the charge on the second capacitor can decay towards the level of charge on the first capacitor to produce a voltage on the second capacitor that is determined by the wheel speed, and control valve means actuated in response to a given voltage level on said second capacitor to relieve the fluid pressure applied to the vehicle brakes.
Claim 2
Dependent Claim
206 words
An anti-lock vehicle brake control system comprising, a source of Fluid pressure to control the braking force on a vehicle wheel, a wheel sensor for producing a train of pulses at a frequency that is related to the vehicle wheel speed, transistor switching means coupled to said wheel sensor to receive said pulse train, a first isolating diode, a first capacitor coupled to said transistor switching means via said first diode, said transistor switching means being responsive to the pulses in said pulse train to cause said first capacitor to be charged to a predetermined voltage level via said first diode, circuit means for discharging said first capacitor during the period between successive pulses in the pulse train, a second capacitor, a charge circuit including a source of voltage permanently connected to said second capacitor, a second isolating diode coupling said first and second capacitors together so that the charge on the second capacitor can decay towards the level of charge on the first capacitor to produce a voltage on the second capacitor that is determined by the wheel speed, and control valve means actuated in response to a given voltage level on said second capacitor to relieve the fluid pressure applied to the vehicle brakes.
Claim 3
Dependent Claim
136 words
A brake control system as claimed in claim 1 wherein said transistor switching means comprises, an input transistor coupled to the wheel sensor, means for biasing said input transistor at its threshold of conduction so that each pulse received turns the transistor on thereby producing at its output electrode a square wave voltage at the pulse frequency, a differentiating circuit coupled to said transistor output electrode for differentiating each cycle of said square wave voltage, a switching transistor which is normally biased into conduction, and means coupling the output electrode of the switching transistor to the first diode and the input of said switching transistor to the output of the differentiating circuit so that the switching transistor is cut-off in response to the leading voltage spike produced therein during each cycle of the square wave voltage.
Claim 4
Dependent Claim
74 words
A brake control system as claimed in claim 2 wherein said switching transistor output electrode is the collector electrode, means connecting said first diode and said first capacitor in series to said collector electrode, a resistor connected in shunt with the first diode, a second resistor connecting said collector to a source of DC voltage, said first capacitor being charged via said second resistor and said first diode when said switching transistor is cut-off.
Claim 5
Dependent Claim
30 words
A brake control system as claimed in claim 3 wherein said circuit means for discharging the first capacitor comprises said shunt resistor and the emitter-collector path of the switching transistor.
Claim 6
Dependent Claim
31 words
A brake control system as claimed in claim 2 wherein said first and second diodes are series connected with opposite polarity between the switching transistor output electrode and the second capacitor.
Claim 7
Dependent Claim
109 words
A brake control system as claimed in claim 1 wherein said transistor switching means comprises, an input transistor coupled to the wheel sensor, means for biasing said input transistor at its threshold of conduction so that the transistor undergoes a change of its conductive state in response to each pulse received, a differentiating circuit coupled to said transistor output electrode for differentiating the output pulses appearing thereat to produce positive going and negative going voltage spikes, the voltage spikes of one polarity being applied through said first diode to charge said first capacitor, and a resistor connected in shunt with said first capacitor to provide a discharge path therefor.
Claim 8
Dependent Claim
39 words
A brake control system as claimed in claim 6 further comprising a third diode connected between the output of the differentiating circuit and ground and poled so as to bypass to ground the voltage spikes of the other polarity.
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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) | 1975-05-09 | 1975-11-08 | 1976-05-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-05-09 | 1979-11-08 | 1980-05-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-05-09 | 1983-11-08 | 1984-05-09 | $7700.00 | Window Closed / Lapsed |