US3921046A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Elevator speed control apparatus
Assignee: Mitsubishi Electric Corp
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Filing: 1973-12-18
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Granted: 1975-11-18
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Expires: 1993-12-18
Abstract
Abstract An apparatus comprising a first device having a frequency characteristic for controlling the speed of an elevator cage driven by an induction motor. The cage speed is controlled by changing the voltage applied to the motor according to the output of the first device connected into a control system. The apparatus further comprises a second device capable of cancelling the frequency characteristic of the first device and of generating a signal for setting the output of the first device to a value corresponding to the input to the first device. The signal from the second device is supplied to the first device prior to the deceleration of the cage.
Inventors
- 👤 Nobuo Anzai
- 👤 Hiroshi Kamaike
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 05:36
CPC Classifications
B; B66; B66B; B66B1/00; B66B1/24; B66B1/28; B66B1/285; H; H02; H02P; H02P23/00; H02P23/20
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
235 words
Apparatus for controlling an elevator cage driven through an induction motor comprising: means for generating a speed command signal; means for generating an actual speed signal, means for comparing the speed command signal and the actual speed signal to generate a resultant difference signal; a delay characteristic circuit having first switch means therein for applying a delay characteristic to the resultant difference signal when the first switch means is in a first state and for applying no delay characteristic to the resultant difference signal when the first Switch means is in a second state; a saturation signal generating circuit having its input connected to the output of the delay characteristic circuit and having second switch means therein for generating a saturation signal to be applied to a distribution circuit when the second switch means is in a first state and for applying the output of the delay characteristic circuit to the distribution circuit when the second switch means is in a second state, the first switch means being switched from its first state to its second state at a given deceleration decision point and being switched from its second state to its first state upon reaching a deceleration command point, the second switch means being switched from its second state to its first state after the end of acceleration and being switched from its first state to its second state at the beginning of deceleration.
Claim 2
Dependent Claim
235 words
Apparatus for controlling an elevator cage driven through an induction motor comprising: means for generating a speed command signal; means for generating an actual speed signal, means for comparing the speed command signal and the actual speed signal to generate a resultant difference signal; a delay characteristic circuit having first switch means therein for applying a delay characteristic to the resultant difference signal when the first switch means is in a first state and for applying no delay characteristic to the resultant difference signal when the first Switch means is in a second state; a saturation signal generating circuit having its input connected to the output of the delay characteristic circuit and having second switch means therein for generating a saturation signal to be applied to a distribution circuit when the second switch means is in a first state and for applying the output of the delay characteristic circuit to the distribution circuit when the second switch means is in a second state, the first switch means being switched from its first state to its second state at a given deceleration decision point and being switched from its second state to its first state upon reaching a deceleration command point, the second switch means being switched from its second state to its first state after the end of acceleration and being switched from its first state to its second state at the beginning of deceleration.
Claim 3
Dependent Claim
37 words
Apparatus for controlling an elevator cage driven by an induction motor in accordance with claim 1 wherein the second switch means is switched from its second state to its first state immediately after the end of acceleration.
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) | 1978-11-17 | 1979-05-19 | 1979-11-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-11-17 | 1983-05-19 | 1983-11-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-11-17 | 1987-05-19 | 1987-11-18 | $7700.00 | Window Closed / Lapsed |