US3887856A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Push-button-operated motor speed control circuit
Assignee: Unisys Corp
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Filing: 1973-10-02
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Granted: 1975-06-03
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Expires: 1993-10-02
Abstract
Abstract A push-button-operated motor speed control circuit for use in a bidirectional speed control system for a film drive motor. The push buttons control the operation of switches for variably charging or discharging a storage capacitor which supplies a biasing potential to the gate of a field-effect transistor. The variable level of charge on the capacitor determines the amount of current passed by the FET, and variations in this current may then be used to vary the running speed of the film drive motor. An infinite number of speeds between predetermined upper and lower limits is made possible by the infinite number of possible voltage levels on the storage capacitor. The level of voltage stored on the capacitor is determined by the length of time that a push button is depressed, and both the steady state value of voltage on the capacitor and the steady state value of the motor speed are those values existing at the instant that the push button is released.
Inventors
- 👤 Frank N Cicchiello
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 03:33
CPC Classifications
H; H02; H02P; H02P7/00; H02P7/06; H02P7/18; H02P7/24; H02P7/28; H02P7/285; H02P7/288; H02P7/2885; Y; Y10; Y10S; Y10S388/00; Y10S388/907; Y10S388/91
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
168 words
A motor speed control system for controlling current flow to a motor comprising: current-control means including two current-carrying electrodes, and a control electrode having substantially complete current flow isolation with respect to said current-carrying electrodes, said current-control means being coupleable to the motor for controlling current flow to the motor as the function of a voltage level upon said control electrode; means coupleable to the motor for providing a settable minimum current flow level to the motor; a capacitor connected to said control electrode for controlling the voltage level on said control electrode in proportion to the charge on said capacitor; first manually operable means having a controllable duration of actuation for charging said capacitor, the charging of said capacitor being directly proportional to the duration of actuation of said first manually operable means; and second manually operable means having a controllable duration of actuation for discharging said capacitor, the discharging of said capacitor being directly proportional to the duration of actuation of said second manually operable means.
Claim 2
Dependent Claim
168 words
A motor speed control system for controlling current flow to a motor comprising: current-control means including two current-carrying electrodes, and a control electrode having substantially complete current flow isolation with respect to said current-carrying electrodes, said current-control means being coupleable to the motor for controlling current flow to the motor as the function of a voltage level upon said control electrode; means coupleable to the motor for providing a settable minimum current flow level to the motor; a capacitor connected to said control electrode for controlling the voltage level on said control electrode in proportion to the charge on said capacitor; first manually operable means having a controllable duration of actuation for charging said capacitor, the charging of said capacitor being directly proportional to the duration of actuation of said first manually operable means; and second manually operable means having a controllable duration of actuation for discharging said capacitor, the discharging of said capacitor being directly proportional to the duration of actuation of said second manually operable means.
Claim 3
Dependent Claim
168 words
A motor speed control system for controlling current flow to a motor comprising: current-control means including two current-carrying electrodes, and a control electrode having substantially complete current flow isolation with respect to said current-carrying electrodes, said current-control means being coupleable to the motor for controlling current flow to the motor as the function of a voltage level upon said control electrode; means coupleable to the motor for providing a settable minimum current flow level to the motor; a capacitor connected to said control electrode for controlling the voltage level on said control electrode in proportion to the charge on said capacitor; first manually operable means having a controllable duration of actuation for charging said capacitor, the charging of said capacitor being directly proportional to the duration of actuation of said first manually operable means; and second manually operable means having a controllable duration of actuation for discharging said capacitor, the discharging of said capacitor being directly proportional to the duration of actuation of said second manually operable means.
Claim 4
Dependent Claim
168 words
A motor speed control system for controlling current flow to a motor comprising: current-control means including two current-carrying electrodes, and a control electrode having substantially complete current flow isolation with respect to said current-carrying electrodes, said current-control means being coupleable to the motor for controlling current flow to the motor as the function of a voltage level upon said control electrode; means coupleable to the motor for providing a settable minimum current flow level to the motor; a capacitor connected to said control electrode for controlling the voltage level on said control electrode in proportion to the charge on said capacitor; first manually operable means having a controllable duration of actuation for charging said capacitor, the charging of said capacitor being directly proportional to the duration of actuation of said first manually operable means; and second manually operable means having a controllable duration of actuation for discharging said capacitor, the discharging of said capacitor being directly proportional to the duration of actuation of said second manually operable means.
Claim 5
Dependent Claim
48 words
The motor speed control system of claim 1, wherein said current-control means further includes means for providing a settable maximum current flow level to the motor, and means for insuring a linear control of current flow to the motor between said maximum and said minimum current flow levels.
Claim 6
Dependent Claim
54 words
The motor speed control system of claim 1, wherein said current control means includes an FET transistor, said control electrode includes the gate electrode of said FET transistor, one of said current-carrying electrodes includes the drain of said FET transistor, and the other of said current-carrying electrodes includes the source of said FET transistor.
Claim 7
Dependent Claim
42 words
The motor speed control system of claim 1, which further includes: means coupled to said minimum current flow level means for disabling said minimum current flow level means; and discharging means coupled to said control electrode for substantially immediately discharging said capacitor.
Claim 8
Dependent Claim
64 words
The motor speed control system of claim 4, which further includes: a first switching element having a duration of actuation controlled by said first manually operable means; a second switching element having a duration of actuation controlled by said second manually operable means; and third manually operable means for controlling said discharging means and said means for disabling said minimum current flow level means.
Claim 9
Dependent Claim
91 words
The motor speed control system of claim 5, wherein said first, second, and third manually operable means include first, second and third pushbuttons and relay coils, respectively; the period of depression of said first and second pushbuttons controlling the energization of said first and second relay coils for determining the duration of actuation of said first and second switching elements, respectively; and any depression of said third pushbutton being operable to energize said third relay coil for controlling said switching means and said means for disabling said minimum current flow means.
Claim 10
Dependent Claim
39 words
The motor speed control system of claim 3, wherein said means for providing a settable maximum current flow level to the motor includes variable resistive means coupled to the drain of said FET for adjustably limiting current flow thereto.
Claim 11
Dependent Claim
52 words
The motor speed control system of claim 1, wherein said means for providing a settable minimum current flow level to the motor includes a voltage divider, said voltage divider including a potentiometer for setting said minimum current flow level, and said potentiometer including a wiper connected to the source of said FET.
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) | 1978-06-02 | 1978-12-02 | 1979-06-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-06-02 | 1982-12-02 | 1983-06-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-06-02 | 1986-12-02 | 1987-06-03 | $7700.00 | Window Closed / Lapsed |