Patent US3660730A successfully refreshed from Google Patents.
US3660730A
Expired / Lapsed
US
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Solenoid drive circuit
Assignee: Design Elements Inc
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Filing: 1970-12-16
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Granted: 1972-05-02
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Expires: 1990-12-16
Abstract
Abstract A circuit for initially applying an unusually large drive voltage to a solenoid coil and for subsequently reducing the applied voltage during the travel of the solenoid plunger. The solenoid coil is serially connected to a first transistor circuit operating as an on-off switch and also is serially connected to a second transistor circuit operating to variably control the voltage applied to the solenoid. A capacitor-charge timing circuit controls the variable transistor and thereby gradually reduces the voltage applied to the solenoid.
Inventors
- 👤 Edwin E Mason
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 13:19
CPC Classifications
H; H01; H01F; H01F7/00; H01F7/06; H01F7/08; H01F7/18; H01F7/1805; B; B41; B41J; B41J7/00; B41J7/36; B41J7/46
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
196 words
A solenoid drive circuit for energizing and de-energizing a solenoid in response to suitable signals at a drive circuit input, said circuit comprising: a. a first electronic switch means in series with said solenoid and a source of driving power, for switching current through the solenoid, the first switch means including and being controlled at said drive circuit input; b. an electronic valve means connected in series with the solenoid at one solenoid terminal for variably controlling a portion of the current through said solenoid, the valve means having a control input; c. a timing means for providing a time changing current for controlling said valve means and comprising serially connected timing resistance, capacitance, and a diode connected to permit current flow charging the capacitance, said timing means connected between the control input of said valve means and a source of d.c. electrical power; and d. capacitance discharge means for at times discharging the capacitance and comprising a second electronic switch means connected across said capacitance, the control input of the second electronic switch means connected to have at least the voltage across said diode applied to the control input of the second electronic switch means.
Claim 2
Dependent Claim
196 words
A solenoid drive circuit for energizing and de-energizing a solenoid in response to suitable signals at a drive circuit input, said circuit comprising: a. a first electronic switch means in series with said solenoid and a source of driving power, for switching current through the solenoid, the first switch means including and being controlled at said drive circuit input; b. an electronic valve means connected in series with the solenoid at one solenoid terminal for variably controlling a portion of the current through said solenoid, the valve means having a control input; c. a timing means for providing a time changing current for controlling said valve means and comprising serially connected timing resistance, capacitance, and a diode connected to permit current flow charging the capacitance, said timing means connected between the control input of said valve means and a source of d.c. electrical power; and d. capacitance discharge means for at times discharging the capacitance and comprising a second electronic switch means connected across said capacitance, the control input of the second electronic switch means connected to have at least the voltage across said diode applied to the control input of the second electronic switch means.
Claim 3
Dependent Claim
33 words
A solenoid drive circuit according to claim 1 whErein said source of d.c. electrical power is at the other solenoid terminal and a dissipating resistance is serially connected to said second electronic switch.
Claim 4
Dependent Claim
36 words
A circuit according to claim 2 wherein there is provided a holding current conducting means, connected parallel to said valve means for permitting a minimum holding current to flow through the solenoid, bypassing the valve means.
Claim 5
Dependent Claim
21 words
A drive circuit according to claim 2 wherein an input resistance is connected across the input terminals of said valve means.
Claim 6
Dependent Claim
34 words
A drive circuit according to claim 4 wherein the valve means is a field effect transistor having its gate connected to said charging circuit and the charging current flows substantially through said input resistance.
Claim 7
Dependent Claim
36 words
A drive circuit according to claim 2 wherein the valve means comprises a bipolar transistor connected in a common emitter configuration and wherein the timing circuit charging current is substantially emitter-base current of said bipolar transistor.
Claim 8
Dependent Claim
48 words
A drive circuit according to claim 2 wherein a. said series capacitance and diode share a common node; and b. said second electronic switch is a transistor having its common terminal connected to said common node and its input terminal connected to the opposite side of the diode.
Claim 9
Dependent Claim
84 words
A drive circuit according to claim 7 wherein a. the valve means comprises a bipolar transistor connected in a common emitter configuration and wherein the timing circuit charging current is substantially emitter base current of said bipolar transistor; b. a leakage resistance is connected between the emitter and base terminals of said bipolar transistor; and c. a holding current conducting means is connected parallel to said valve means for permitting a minimum holding current to flow through the solenoid by passing the valve means.
Claim 10
Dependent Claim
70 words
A circuit according to claim 8 wherein a. said first electronic switch means is a darlington amplifier connected between a common terminal of said power supply and said solenoid; and b. said holding current conducting means is a resistor having a resistance approximately equal to Ecc/Imin - Rs where Rs is the solenoid d.c. resistance, Ecc is the voltage of said source and Imin is the minimum solenoid holding current.
Claim 11
Dependent Claim
29 words
A circuit according to claim 9 wherein said timing capacitance is approximately in the range of 1 microfarad to 4 microfarads and said timing resistance is approximately 2200 ohms.
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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) | 1975-05-02 | 1975-11-01 | 1976-05-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-05-02 | 1979-11-01 | 1980-05-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-05-02 | 1983-11-01 | 1984-05-02 | $7700.00 | Window Closed / Lapsed |