US4631467A
Expired / Lapsed
US
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Escalator passenger flow control
Assignee: Otis Elevator Co
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Filing: 1985-05-28
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Granted: 1986-12-23
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Expires: 2005-05-28
Abstract
Abstract A variable-frequency, variable-voltage (VVVF) converter is interposed in the line between an AC source and an asynchronous escalator motor. Current to the motor is sensed to determine load in conjunction with a passenger detector and load simulating electronic system and the frequency and voltage of the converter are automatically adjusted in response thereto to control escalator speed. The system includes a converter to supply the asynchronous drive motor of the escalator with variable frequency and an appropriate control circuit for manual or automatic operation of the escalator at different speeds, which is equivalent to different motor frequencies.
Inventors
- 👤 Dietrich E. Herrmann
- 👤 Detlev Abraham
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 18:42
CPC Classifications
H; H02; H02P; H02P27/00; H02P27/04; H02P27/045; B; B66; B66B; B66B25/00; Y; Y02; Y02B; Y02B50/00
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
165 words
A circuit for providing a load signal (74) indicative of the number of passengers on an escalator, comprising: means (66) for providing a step speed signal (f step ) indicative of the speed of the escalator; means (77) for providing a step number signal (s) indicative of the number of steps in an escalator run; sensor means (60) for providing an entry signal (P) indicative of the entry of a passenger onto the escalator; variable length shift register means (76) for providing a down signal (78) in response to the entry signal (p) having moved through the shift register, wherein the length of the register is determined by the step number signal (s) and the rate of the register is determined by the step speed signal (f step ); and up/down counter means (72) for incrementing the load signal (74) in response to each occurrence of the entry signal and for decrementing the load signal in response to each occurrence of the down signal (78).
Claim 2
Dependent Claim
165 words
A circuit for providing a load signal (74) indicative of the number of passengers on an escalator, comprising: means (66) for providing a step speed signal (f step ) indicative of the speed of the escalator; means (77) for providing a step number signal (s) indicative of the number of steps in an escalator run; sensor means (60) for providing an entry signal (P) indicative of the entry of a passenger onto the escalator; variable length shift register means (76) for providing a down signal (78) in response to the entry signal (p) having moved through the shift register, wherein the length of the register is determined by the step number signal (s) and the rate of the register is determined by the step speed signal (f step ); and up/down counter means (72) for incrementing the load signal (74) in response to each occurrence of the entry signal and for decrementing the load signal in response to each occurrence of the down signal (78).
Claim 3
Dependent Claim
67 words
A circuit according to claim 1 characterized by: means (65b) for providing a first signal (r) indicative of the speed ratio of the escalator drive motor and step chain; means (65a) for providing a second signal (f m ) indicative of the escalator drive motor speed; and divider means (64) for providing the step speed signal (f step ) in response to the first and second signals.
Claim 4
Dependent Claim
44 words
A circuit according to claim 1 characterized by: logic means (68) for altering the value of the signal (P) based on the possible number of passengers on the steps, which depends on the step width and empirical values describing the loading of the escalator.
Claim 5
Dependent Claim
246 words
An escalator comprising: an asynchronous drive motor (20); a control circuit (22) for providing variable-frequency control pulses (V f ), the frequency of which are related to a speed reference signal (n) indicative of a desired running speed for the drive motor (20); a variable-frequency, variable-voltage inverter (18) connected to the drive motor (20) for controlling the speed thereof in response to the frequency of the variable-frequency control pulses (V f ) from the control circuit (22); characterized by: means (66) for providing a step speed signal (f step ) indicative of the speed of the escalator; means (77) for providing a step number signal (s) indicative of the number of steps in an escalator run; sensor means (60) for providing an entry signal (P) indicative of the entry of a passenger onto the escalator; variable length shift register means (76) for providing a down signal (78) in response to the entry signal (p) having moved through the shift register, wherein the length of the register is determined by the step number signal (s) and the rate of register is determined by the step speed signal (f step ); and up/down counter means (72) for incrementing the load signal (74) in response to each occurrence of the entry signal and for decrementing the load signal in response to each occurrence of the down signal (78); and means (80) for providing the speed reference signal (n) to the controller as a function of the load signal (74).
Claim 6
Dependent Claim
246 words
An escalator comprising: an asynchronous drive motor (20); a control circuit (22) for providing variable-frequency control pulses (V f ), the frequency of which are related to a speed reference signal (n) indicative of a desired running speed for the drive motor (20); a variable-frequency, variable-voltage inverter (18) connected to the drive motor (20) for controlling the speed thereof in response to the frequency of the variable-frequency control pulses (V f ) from the control circuit (22); characterized by: means (66) for providing a step speed signal (f step ) indicative of the speed of the escalator; means (77) for providing a step number signal (s) indicative of the number of steps in an escalator run; sensor means (60) for providing an entry signal (P) indicative of the entry of a passenger onto the escalator; variable length shift register means (76) for providing a down signal (78) in response to the entry signal (p) having moved through the shift register, wherein the length of the register is determined by the step number signal (s) and the rate of register is determined by the step speed signal (f step ); and up/down counter means (72) for incrementing the load signal (74) in response to each occurrence of the entry signal and for decrementing the load signal in response to each occurrence of the down signal (78); and means (80) for providing the speed reference signal (n) to the controller as a function of the load signal (74).
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) | 1989-12-22 | 1990-06-23 | 1990-12-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-12-22 | 1994-06-23 | 1994-12-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-12-22 | 1998-06-23 | 1998-12-23 | $7700.00 | Window Closed / Lapsed |