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US4535879A
Expired / Lapsed
US
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Control system for controlling the engagement of a pressure-operated actuator
Assignee: Rockford Powertrain Inc
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Filing: 1984-02-29
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Granted: 1985-08-20
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Expires: 2004-02-29
Abstract
Abstract A smooth, optimum engagement of a pressure-operated actuator, such as a brake or clutch, is obtained by producing a pulse width modulated signal, having a gradually changing duty cycle, which is then used to control a three-way on/off solenoid valve to which is supplied pressurized fluid such as air. The solenoid valve is rapidly switched between pressure in and exhaust out in accordance with the changing duty cycle in order to develop a gradually increasing fluid pressure for application to the actuator.
Inventors
- 👤 Fred D. Sturges
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 13:40
CPC Classifications
F; F16; F16D; F16D48/00; F16D48/06; F16D48/066; F16D48/02; F16D2048/0257; F16D2048/0269; F16D2500/00; F16D2500/10; F16D2500/102; F16D2500/1028; F16D2500/50; F16D2500/502; F16D2500/50239; F16D2500/70; F16D2500/704; F16D2500/70402; F16D2500/7041; F16D2500/70414; F16D2500/71; F16D2500/7107; F16D2500/7109
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
66 words
A control system for controlling the rate of engagement of a pressure-operated actuator, comprising: means for developing a pulse width modulated signal having a duty cycle which gradually changes in a constant direction; means responsive to said pulse width modulated signal for producing a gradually increasing fluid pressure; and means for applying the gradually increasing fluid pressure to the actuator to effect a smooth engagement thereof.
Claim 2
Dependent Claim
66 words
A control system for controlling the rate of engagement of a pressure-operated actuator, comprising: means for developing a pulse width modulated signal having a duty cycle which gradually changes in a constant direction; means responsive to said pulse width modulated signal for producing a gradually increasing fluid pressure; and means for applying the gradually increasing fluid pressure to the actuator to effect a smooth engagement thereof.
Claim 3
Dependent Claim
95 words
A control system for controlling the fluid pressure applied to a pressure-operated actuator to optimize the rate of engagement of the actuator, comprising: a pulse width modulation circuit for developing a pulse width modulated signal; control means for controlling said pulse width modulation circuit to gradually change the duty cycle of the pulse width modulated signal in a constant direction; means responsive to said pulse width modulated signal for producing a gradually increasing fluid pressure; and means for applying the gradually increasing fluid pressure to the actuator to effect a smooth engagement of the actuator.
Claim 4
Dependent Claim
95 words
A control system for controlling the fluid pressure applied to a pressure-operated actuator to optimize the rate of engagement of the actuator, comprising: a pulse width modulation circuit for developing a pulse width modulated signal; control means for controlling said pulse width modulation circuit to gradually change the duty cycle of the pulse width modulated signal in a constant direction; means responsive to said pulse width modulated signal for producing a gradually increasing fluid pressure; and means for applying the gradually increasing fluid pressure to the actuator to effect a smooth engagement of the actuator.
Claim 5
Dependent Claim
14 words
A control system according to claim 2 wherein the fluid pressure is air pressure.
Claim 6
Dependent Claim
13 words
A control system according to claim 2 wherein the actuator is a clutch.
Claim 7
Dependent Claim
57 words
A control system according to claim 2 wherein the gradually increasing fluid pressure is produced by supplying pressurized fluid to a three-way on/off solenoid valve which is rapidly switched between pressure in and exhaust out in response to the pulse width modulated signal, the fluid pressure applied to the actuator being proportional to the signal's duty cycle.
Claim 8
Dependent Claim
30 words
A control system according to claim 2 and including means for changing the rate at which the duty cycle changes in order to vary the engagement rate of the actuator.
Claim 9
Dependent Claim
59 words
A control system according to claim 2 wherein said pulse width modulation circuit includes a triangular wave generator, for producing a triangular shaped signal, and a comparator, the triangular shaped signal along with a gradually changing control signal, developed by said control means, being applied to said comparator to produce said pulse width modulated signal at the comparator's output.
Claim 10
Dependent Claim
50 words
A control system according to claim 7 and including means for establishing said control signal at a fixed amplitude level, which causes the comparator's output to be held at a constant amplitude level, in order to provide a zero fluid pressure to establish and to maintain disengagement of the actuator.
Claim 11
Dependent Claim
82 words
A control system according to claim 7 wherein said control means includes a capacitor; means for charging the capacitor relatively rapidly to apply a constant-amplitude control signal to the comparator, which results in a fixed amplitude level at the comparator's output and a zero fluid pressure; and means for discharging the capacitor relatively slowly to apply a gradually decreasing control signal to the comparator to gradually increase the duty cycle of the pulse width modulated signal and gradually increase the fluid pressure.
Claim 12
Dependent Claim
30 words
A control system according to claim 9 and including means for varying the rate at which the capacitor discharges in order to change the rate of engagement of the actuator.
Claim 13
Dependent Claim
30 words
A control system according to claim 7 wherein said control means includes a resistance-capacitance circuit, the capacitance discharging relatively slowly through the resistance to produce the gradually changing control signal.
Claim 14
Dependent Claim
39 words
A control system according to claim 11 wherein said capacitance is held in a charged condition to maintain a fixed amplitude control signal which results in a fixed amplitude level at the comparator's output and a zero fluid pressure.
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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) | 1988-08-19 | 1989-02-18 | 1989-08-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-08-19 | 1993-02-18 | 1993-08-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-08-19 | 1997-02-18 | 1997-08-20 | $7700.00 | Window Closed / Lapsed |