US3783362A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Electronic control device for intermittent operation of a windscreen wiper, particularly for motor vehicles
Assignee: Industrie Magneti Marelli SRL
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Filing: 1971-11-02
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Granted: 1974-01-01
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Expires: 1991-11-02
Abstract
Abstract An adjustable electronic timing device for controlling the operating speed of windscreen wipers. A switch is provided for operating the wipers in either a continuous or an intermittent fashion. During intermittent operation, a programmable unijunction transistor (PUT) is caused to conduct to trigger an SCR which is connected in circuit to the wiper motor. A capacitor is charged during each wiping cycle and discharges at the termination of each wiping cycle to prevent retriggering of the SCR until the capacitor is fully discharged. The wiper operating frequency is adjusted by adjusting the resistivity of the discharge path for the capacitor. A braking circuit is provided for dynamic braking of the wiper motor.
Inventors
- 👤 E Basso
- 👤 G Viviani
- 👤 L Cartabia
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 17:56
CPC Classifications
B; B60; B60S; B60S1/00; B60S1/02; B60S1/04; B60S1/06; B60S1/08; B60S1/0803; B60S1/0807; Y; Y10; Y10S; Y10S318/00; Y10S318/02
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
315 words
An electronic control device for a windscreen wiper motor having a pair of input terminals comprising: a supply source; a wiper selector switch connected to said source; a silicon controlled rectifier (SCR) for connecting said switch to a first input terminal of said motor; said selector switch being operable between an open and a closed position; timing circuit means comprising a programmable unijunction transistor (PUT) having anode and cathode electrodes coupled between said selector switch and the trigger electrode of the SCR and having a gate electrode; a timing capacitor coupled between the remaining input terminal of the motor and said gate electrode; charging means coupled between said timing capacitor and said SCR for abruptly charging said capacitor when said SCR conducts; said PUT being rendered conductive only when the voltage level at its gate electrode is below the voltage at its anode to immediately trigger the SCR into conduction upon closure of said selector switch; said timing capacitor being adapted to charge to a voltage level higher than the voltage level at its anode to prevent said motor from operating for a predetermined time interval after completion of one wiping cycle; said motor means including switch means operated by said motor for directly coupling the first input terminal of said motor to said source as soon as the motor is energized to begin an operating cycle causing said SCR to be turned off and for disconnecting said motor from said source at the end of each wiping cycle; discharge means coupled across said capacitor for controlling the discharge rate of the timing capacitor and thereby controlling the time interval between the end of a wiping cycle and the beginning of the next wiping cycle by controlling the time interval required for the voltage level applied by the timing capacitor to the PUT gate electrode to fall below the voltage level at said PUT anode.
Claim 2
Dependent Claim
315 words
An electronic control device for a windscreen wiper motor having a pair of input terminals comprising: a supply source; a wiper selector switch connected to said source; a silicon controlled rectifier (SCR) for connecting said switch to a first input terminal of said motor; said selector switch being operable between an open and a closed position; timing circuit means comprising a programmable unijunction transistor (PUT) having anode and cathode electrodes coupled between said selector switch and the trigger electrode of the SCR and having a gate electrode; a timing capacitor coupled between the remaining input terminal of the motor and said gate electrode; charging means coupled between said timing capacitor and said SCR for abruptly charging said capacitor when said SCR conducts; said PUT being rendered conductive only when the voltage level at its gate electrode is below the voltage at its anode to immediately trigger the SCR into conduction upon closure of said selector switch; said timing capacitor being adapted to charge to a voltage level higher than the voltage level at its anode to prevent said motor from operating for a predetermined time interval after completion of one wiping cycle; said motor means including switch means operated by said motor for directly coupling the first input terminal of said motor to said source as soon as the motor is energized to begin an operating cycle causing said SCR to be turned off and for disconnecting said motor from said source at the end of each wiping cycle; discharge means coupled across said capacitor for controlling the discharge rate of the timing capacitor and thereby controlling the time interval between the end of a wiping cycle and the beginning of the next wiping cycle by controlling the time interval required for the voltage level applied by the timing capacitor to the PUT gate electrode to fall below the voltage level at said PUT anode.
Claim 3
Dependent Claim
28 words
The device of claim 1 further comprising a voltage divider coupled between said source and said PUT anode for controlling the voltage level applied to the PUT anode.
Claim 4
Dependent Claim
26 words
The device of claim 1 further comprising a smoothing capacitor coupled between the PUT anode and reference potential for smoothing the input to the PUT anode.
Claim 5
Dependent Claim
40 words
The device of claim 1 wherein said discharge means further comprises an adjustable resistance element for altering the discharge rate of the timing capacitor, said discharge circuit (R4, R5) of said control capacitor (C1) is of a variable time constant.
Claim 6
Independent Claim
12 words
The device of claims 1 wherein said charging means comprises a diode.
Claim 7
Dependent Claim
41 words
The device of claim 1 further comprising series connected resistor element and capacitor element coupled across the input terminals of the motor for preventing undesirable discharge of said timing capacitor and hence preventing spurious triggering of the SCR by the PUT.
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) | 1976-12-31 | 1977-07-02 | 1978-01-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-12-31 | 1981-07-02 | 1982-01-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-12-31 | 1985-07-02 | 1986-01-01 | $7700.00 | Window Closed / Lapsed |