Patent Publication Number: US-2016221792-A1

Title: Locking device for elevator car

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The invention relates to elevator safety devices and more particularly to a locking device including locking members each having a spring biased lock pin adapted to insert into a hole of a plate member mounted on a surface of a shaft when the door of a cab of an elevator is open or retract when the door is closed. 
     2. Description of Related Art 
     A cab of an elevator may slip after being locked after arriving at a desired floor. This is because, after a long period of time of use, there is wear of the hoist ropes, low adhesive friction between the hoist ropes and the drive sheave, overload of the car, etc. 
     Thus, the need for improvement of the locking device for an elevator still exists. 
     SUMMARY OF THE INVENTION 
     It is therefore one object of the invention to provide a locking device comprising two sets of a plurality of locking members disposed on two sides of a cab of an elevator respectively, each locking member including a spring-biased retractable lock pin extending out of either side of the cab; and two sets of a plurality of plate members disposed on two opposite surfaces of a shaft respectively, each plate member including a hole aligned with the lock pin; wherein the locking members co-act with a door of the cab; and wherein the lock pin is configured to either extend into the hole for locking the door of the cab when the door of the cab is open or remove out of the hole for unlocking the door of the cab when the door of the cab is closed. 
     The above and other objects, features and advantages of the invention will become apparent from the following detailed description taken with the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of the cab of an elevator incorporating a locking device according to a first preferred embodiment of the invention; 
         FIG. 2  is a side view in part section showing the unlocked locking member when the cab door is closed; 
         FIG. 3  is a view similar to  FIG. 2  showing the locked locking member when the cab door is open; 
         FIG. 4  is a view similar to  FIG. 3  showing the lock pin (i.e., the car) prevented from moving further upward when contacts an upper end of the hole; 
         FIG. 5  is a view similar to  FIG. 3  showing the lock pin (i.e., the car) prevented from moving further downward when contacts a lower end of the hole; and 
         FIG. 6  is a perspective view of an elevator incorporating a locking device according to a second preferred embodiment of the invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring to  FIGS. 1 to 5 , a locking device for a cab  20  of an elevator  1  installed in a shaft  10  in accordance with a first preferred embodiment of the invention is shown and discussed in detail below. 
     The cab  20  is hoisted by hoist ropes  50  and includes a door  21 . The locking device includes two locking members  30  provided on two sides of the cab  20  respectively. The locking member  30  includes a retractable lock pin  31  extending out of one side, and a torsion spring  32  put on the lock pin  31 . Two plate members  40  are provided on two opposite surfaces of the shaft  10  at each floor respectively. The plate member  40  includes a hole  41  aligned with the lock pin  31 . 
     The locking member  30  co-acts with the door  21 . In detail, the lock pin  31  may extend into the hole  41  for locking the door  21  when the door  21  is open and the lock pin  31  may remove out of the hole  41  for unlocking the door  21  when the door  21  is closed. 
     As shown in  FIGS. 4 and 5 , the hole  41  is greatly larger than the forward end of the lock pin  31  so that an allowance between the hole  41  and the lock pin  31  is planned. 
     Referring to  FIG. 6 , a locking device for a cab  20  of an elevator  1  installed in a shaft  10  in accordance with a second preferred embodiment of the invention is shown. The characteristics of the second preferred embodiment are substantially the same as that of the first preferred embodiment except the following: 
     A plurality of locking members  30  are provided on two sides of the cab  20  respectively. 
     While the invention has been described in terms of preferred embodiments, those skilled in the art will recognize that the invention can be practiced with modifications within the spirit and scope of the appended claims.