Patent US3761793A successfully refreshed from Google Patents.
US3761793A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Device for controlling speed of electric automobile
Assignee: Hitachi Ltd
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Filing: 1972-03-16
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Granted: 1973-09-25
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Expires: 1992-03-16
Abstract
Abstract In an electric automobile, the motor for driving the wheels is powered by an attached battery through a thyristor chopper circuit. The current conduction rate of the chopper circuit is controlled either by the accelerator pedal in case of manual drive or by making a comparison between the actual driving speed and the instructed speed in case of automatic drive so that the manipulation of the automobile is simplified.
Inventors
- 👤 S Naito
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 17:18
CPC Classifications
H; H02; H02P; H02P7/00; H02P7/06; H02P7/18; H02P7/24; H02P7/28; H02P7/285; H02P7/29; H02P7/2913; B; B60; B60K; B60K31/00; B60K31/02; Y; Y10; Y10S; Y10S388/00; Y10S388/907; Y10S388/917; Y10S388/92
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
119 words
A speed control device for use in an electric automobile comprising a driving motor which is powered by a dc supply through a thyristor chopper circuit; a pulse oscillator circuit; a circuit for firing a main thyristor in said thyristor chopper circuit in response to the output of said pulse oscillator circuit; a monostable multivibrator circuit which is driven into its quasi-stable state by means of said pulse oscillator circuit; a circuit for firing a turn-off thyristor in said thyristor chopper circuit when said multivibrator recovers its stable state; and a circuit for controlling the period of said quasi-stable state of said multivibrator depending upon the difference between the instructed speed and the actual driving speed of said automobile.
Claim 2
Dependent Claim
119 words
A speed control device for use in an electric automobile comprising a driving motor which is powered by a dc supply through a thyristor chopper circuit; a pulse oscillator circuit; a circuit for firing a main thyristor in said thyristor chopper circuit in response to the output of said pulse oscillator circuit; a monostable multivibrator circuit which is driven into its quasi-stable state by means of said pulse oscillator circuit; a circuit for firing a turn-off thyristor in said thyristor chopper circuit when said multivibrator recovers its stable state; and a circuit for controlling the period of said quasi-stable state of said multivibrator depending upon the difference between the instructed speed and the actual driving speed of said automobile.
Claim 3
Dependent Claim
83 words
A speed control device according to claim 1, wherein said circuit for controlling the period of said quasi-stable state of saId multivibrator comprises a transistor, a manual control circuit, an automatic control circuit which delivers an output in response to the difference between said instructed speed and said actual driving speed, and a change-over switch which selectively connects the baye circuit of said transistor with either the output terminal of said manual control circuit or the output terminal of said automatic control circuit.
Claim 4
Dependent Claim
63 words
A speed control device according to claim 2, wherein two switches are further provided which are adapted to suppress the oscillation of said pulse oscillator circuit when both of them are actuated, one of which is actuated when said change-over switch selects said manual control circuit, and the other of which is actuated when the accelerator pedal of said automobile is completely released.
Claim 5
Dependent Claim
69 words
A speed control device according to claim 1, further comprising first means providing an output indicative of the instructed speed and second means providing an output indicative of the actual driving speed of said automobile, said circuit being responsive to the outputs of said first and second means for controlling the period of said quasi-stable state of said multivibrator to provide for a constant driving speed for said automobile.
Claim 6
Dependent Claim
32 words
A speed control device according to claim 4, wherein said second means includes a tachometer generator mechanically coupled to one of said driving motor and one of the wheels of said automobile.
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) | 1976-09-24 | 1977-03-26 | 1977-09-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-09-24 | 1981-03-26 | 1981-09-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-09-24 | 1985-03-26 | 1985-09-25 | $7700.00 | Window Closed / Lapsed |