Hydraulic elevator

Abstract

Disclosed is a hydraulic elevator in which the load and/or the oil temperature are detected under the running condition of a cage of the hydraulic elevator and a proper value of the deceleration delay time corresponding to this running condition is obtained to thereby control the flow of pressure-oil on the basis of the proper value of the deceleration delay time. Various values of the deceleration delay time are stored in advance in the form of table with respect to various values of load and oil temperature.

We claim: 
     
       1. In a hydraulic elevator system in which a cage is moved by hydraulic means including a cylinder and a plunger, a control apparatus comprising: instruction means for producing a cage deceleration instruction in response to the cage reaching a predetermined deceleration position in advance of a stop position where the cage is to be stopped;   memory means for storing a plurality of values of deceleration delay time as a function of the temperature of the oil used for driving the hydraulic means and the load of the elevator;   data retrieval means connected to said memory means for retrieving one of said plurality of values corresponding to detected values of the oil temperature and elevator load; and   drive means responsive to said deceleration instruction for causing said cage to begin to decelerate after expiration of a delay time corresponding to the value retrieved by said data retrieval means following the producing of said deceleration instruction by said instruction means.   
     
     
       2. A control apparatus according to claim 1, wherein said memory means includes a plurality of areas for storing said plurality of values, respectively, such that any one of said plurality of values is selectively readout by designating one temperature of a predetermined oil temperature range in which the detected value of the oil temperature exists and one load of a predetermined load range in which the detected value of the elevator load exists. 
     
     
       3. A control apparatus according to claim 2, further comprising computing means for computing correction values of the deceleration delay times stored in said memory means on the basis of the actual running characteristic of the cage, the detected value of the oil temperature and the detected value of the elevator load, including means for using said correction values for correcting the respective values stored in said memory means corresponding to said detected values of the oil temperature and the elevator load. 
     
     
       4. A control apparatus according to claim 3, wherein said correction value is computed on the basis of an expected full running speed of the cage, an expected landing speed of the cage and an expected deceleration time interval which are calculated as a function of the detected values of the oil temperature and the elevator load. .Iadd. 
     
     
       5.  In a hydraulic elevator system in which a cage is moved upwards or downwards by hydraulic means including a hydraulic cylinder and a flow rate control valve and said cage is decelerated in response to the cage reaching a predetermined deceleration-initiating position to reduce its speed to a lower landing-running speed, the combination of: memory means for storing a delay time to be used for controlling the deceleration of said cage;   means for outputting an instruction so as to cause said cage to initiate the deceleration at the delay time read out of said memory means after said cage reaches said deceleration initiating position;   means for controlling the deceleration of said cage according to said instruction as outputted;   means for determining an actual landing time interval during which said cage continues to run at said lower landing-running speed, when the deceleration of said cage has been controlled by said instruction;   means for determining a landing time difference between said actual landing time interval and a desired landing time interval and for correcting said delay time based on said landing time difference; and   means for renewing the delay time stored in said memory means by said corrected delay time. .Iaddend. .Iadd.6. The combination according to claim 5, wherein said actual landing time is determined by estimation as a function of at least one of the load and the oil temperature of the hydraulic elevator system. .Iaddend. .Iadd.7. The combination according to claim 5, wherein said memory means stores a plurality of values of said delay time which can be selectively read out by designating the load and the oil temperature of said hydraulic elevator system. .Iaddend. .Iadd.8. The combination according to claim 5, wherein said memory means stores a plurality of values of said delay time which can be selectively read out by designating one of the load and the oil temperature of said hydraulic elevator system. .Iaddend. .Iadd.9. In a hydraulic elevator system in which a cage is moved by hydraulic means including a cylinder and a plunger, a control apparatus comprising:   instruction means for producing a cage deceleration instruction in response to the cage reaching a predetermined deceleration position in advance of a stop position where the cage is to be stopped;   memory means for storing a plurality of values of deceleration delay time;   data retrieval means connected to said memory means for retrieving one of said plurality of values corresponding to detected values of the oil temperature and elevator load; and   drive means responsive to said deceleration instruction for causing said cage to begin to decelerate after expiration of a delay time corresponding to the value retrieved by said data retrieval means following the producing of said deceleration instruction by said instruction means. .Iaddend.