Leveling control system for hydraulic elevator
First Claim
1. A hydraulic elevator system comprising:
- a car;
a plurality of landings;
jack means for raising and lowering the car between landings;
pump means for supplying pressurized hydraulic fluid;
a hydraulic valve for selectively directing fluid from said pump means to said jack means for raising said car;
level up sensing means for detecting car position at a plurality of selected releveling distances below floor level position; and
processor control means (a) for changing releveling distance responsive to at least one elevator operating parameter;
(b) for selecting an effective hysteresis value as a function at least of releveling distance;
(c) for actuating said pump means responsive to the actuation of said level up sensing means; and
(d) for actuating said hydraulic valve responsive to the actuation of said level up sensing means for a distance dependent upon said effective hysteresis value.
1 Assignment
0 Petitions
Accused Products
Abstract
A hydraulic elevator includes level sensors for establishing dead zones of different sizes and for changing the dead zone while the car is stopped at a floor. A controller selects the size of the dead zone, for purposes of relevel operations, based upon elevator operating state (e.g. doors open or closed, time of day, time since last run) or other parameters (excess oil temperature, motor temperature, or excess motor starts). The controller also selects an effective hysteresis value either to return the car to floor level or to move the car to a position above floor level. In this manner, the controller maintains a small dead zone, and returns the car to level, when the doors are open. When the doors are closed, a larger dead zone is selected to reduce the frequency of relevel operations. Moreover, under certain conditions, the car is moved, during releveling, to a position above the landing, to further reduce the number of required relevel operations over time.
29 Citations
14 Claims
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1. A hydraulic elevator system comprising:
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a car; a plurality of landings; jack means for raising and lowering the car between landings; pump means for supplying pressurized hydraulic fluid; a hydraulic valve for selectively directing fluid from said pump means to said jack means for raising said car; level up sensing means for detecting car position at a plurality of selected releveling distances below floor level position; and processor control means (a) for changing releveling distance responsive to at least one elevator operating parameter;
(b) for selecting an effective hysteresis value as a function at least of releveling distance;
(c) for actuating said pump means responsive to the actuation of said level up sensing means; and
(d) for actuating said hydraulic valve responsive to the actuation of said level up sensing means for a distance dependent upon said effective hysteresis value. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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Specification