Abstract:
An apparatus for moving elevator equipment, particularly an elevator car when stuck in a shaft, comprises a suspension point which is connected to the elevator equipment by an adjustable-height connection. Contrary to the prior art, the suspension point includes a length-adjustable assembly configured for engagement with opposing walls of the shaft or opposing guide rails within the shaft at any chosen location along the shaft. The invention thus provides a localized solution that can be used conveniently at any position within the shaft and is therefore independent of the position, and indeed the presence, of any lifting hooks within the shaft.

Description:
[0001]     The present invention relates to an apparatus for moving elevator equipment disposed within an elevator shaft and is particularly adapted for the release of a car stuck in the shaft.  
       BACKGROUND OF THE INVENTION  
       [0002]     Occasionally, an elevator car can become stuck within a shaft and it is necessary to release the car before the elevator can be returned to normal operation. Such a situation can occur if safety gear mounted on the car has been released to frictionally engage with the guide rails so as to bring the car to an abrupt emergency stop. The energy dissipated through this frictional engagement can in some instances cause the safety gear (and thereby the car) to stick to the guide rails. The common practice to effect the release of the car is to suspend it from a lifting hook located at a position above the car within the hoistway by a rope or cable and to then hoist the rope or cable so as to raise and thereby release the car. This procedure becomes cumbersome and time consuming if the nearest lifting hook is not within easy reach of the car roof.  
       BRIEF DESCRIPTION OF THE INVENTION  
       [0003]     The objective of the present invention is to overcome this problem by providing an apparatus for moving elevator equipment disposed within a shaft. The apparatus comprises a suspension point and height-adjustable means configured for interconnecting the suspension point within the shaft and the elevator equipment. Contrary to the prior art, the suspension point comprises a length adjustable means configured for engagement with opposing walls of the shaft or opposing guide rails within the shaft. Hence, the invention defines a localized solution that can be used conveniently at any position within the shaft and is therefore independent of the position, and indeed the presence, of any lifting hooks within the shaft.  
         [0004]     Preferably, the length adjustable means includes shoes for frictional engagement with the opposing walls of the shaft or opposing guide rails. Accordingly, the user does not have to make any special surface preparation before installing the apparatus. In a preferred embodiment, each shoe has a U-shaped housing defining a tapered channel to receive a blade of the guide rail, the channel being wider at its bottom than at its top, and further comprises a roller for insertion into the channel. This is a quick and effective way of securing the length adjustable means to the opposing guide rails.  
         [0005]     In one embodiment, the length adjustment means includes a bar having opposing ends for insertion into sleeves provided on the opposing shoes. Each of the sleeves may be spring biased away from the bar towards the opposing guide rail or wall. Alternatively, a series of adjustment holes can be provided in the bars and a pin can be passed through the sleeve and one of the adjustment holes to fasten the bar to the sleeve.  
         [0006]     In an alternative embodiment, the length adjustment means may include two interconnectable bars. The bars can be interconnected at a central hub. Preferably, the bars are accommodated in through holes in the hub. As before, each bar can have a series of adjustment holes and can be fastened to the hub by a pin passing through the hub and one of the adjustment holes. Advantageously, the through holes intersect within the hub. Hence each of the bars extends outwards and downwards from the hub to engage with the guide rail or shaft wall. The inclined angle each bar makes with the corresponding guide rail or wall helps enhance the friction therebetween especially when force is exerted on the apparatus. The force exerted through the interconnected bar arrangement has a horizontal as well as a vertical component at the opposing shaft walls or guide rails; the vertical component to overcome the weight and sticking force of the trapped elevator equipment; the horizontal component of the force ensures the shoes are held firmly in place against the opposing shaft walls or guide rails.  
         [0007]     The length adjustable means can include a threaded hole, in which case the height adjustable means can be a threaded bolt for rotatable engagement with the threaded hole of the length adjustable means. Alternatively, a conventional lift device such as a chain block or a rope hoist can be used. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0008]     The invention is herein described by way of specific examples with reference to the accompanying drawings in which:  
         [0009]      FIG. 1  is a general diagrammatic overview of a lifting apparatus according to a first embodiment of the present invention;  
         [0010]      FIG. 2  is a partial plan view of the apparatus of  FIG. 1 ;  
         [0011]      FIG. 3  is a perspective view of the of the hub of the apparatus shown in  FIGS. 1 and 2 ;  
         [0012]      FIG. 4  is a plan view of a lifting apparatus according to a second embodiment of the present invention;  
         [0013]      FIG. 5  is a partial, exploded view of region A in  FIG. 4 , depicting an end shoe of the lifting apparatus; and  
         [0014]      FIG. 6  is a lateral cross-section through the end shoe along line B-B of  FIG. 5 , further depicting a locking mechanism for the end shoe. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0015]      FIG. 1  illustrates a car  6  which is stuck within a shaft  2  of an elevator installation. A lifting apparatus  10  according to a first embodiment of the invention is erected on top of the car  6  to lift and thereby free the car  6 . As shown in  FIG. 2 , the lifting apparatus  10  comprises a square thread bolt  20  having a flange  22  located at its lower end. The flange  22  is inserted into and retained in a space defined between an inner, upper collar  14  and an outer, lower collar  16  of a U-shaped retainer  12  mounted on the roof  8  of the car  6 . The bolt  20  and the flange  22  are freely rotatable with respect to the retainer  12 . A handle  24  is secured to an upper end of the square thread bolt  20  to enable the user to manually rotate the bolt  20 .  
         [0016]     The bolt  20  passes through and engages a correspondingly threaded hole  28  provided in a hub  26 . Accordingly, relative rotation between the hub  26  and the bolt  20  causes the hub  26  to move along the length of the bolt  20 . Two structural tubes  40  are adjustably mounted within holes  30  shown in  FIG. 3  provided through the hub  26  and extend outwards and downwards from either side of the hub  26  towards opposing walls  4  of the shaft  2 . A shoe  46  is pivotally mounted on an end  44  of each tube  40 . Each shoe has a toothed surface  48  to enhance the frictional engagement between the shoe  46  and the shaft wall  4 .  
         [0017]     Once the bolt  20  has been erected on the car roof  8 , the tubes  40  are extended from the hub  26  until the shoes  46  engage with the opposing walls  4  of the shaft  2 . In this position, each tube  40  is inclined to the normal N of the respective wall  4  at an angle α. The tubes  40  are then secured to the hub  26  by retention pins  32  inserted through pin holes  34  in the hub  26  and adjustment holes  42  in the tubes  40  (as shown in  FIG. 3 ).  
         [0018]     The lifting apparatus  10  is now fully installed and in operation the user turns the handle  24  in an anticlockwise direction causing the bolt  20  to move upwards within the hub  26 . After the inherent initial slack in the system has been taken up, the lifting apparatus  10  builds up sufficient lifting force to firstly overcome the weight of the car and then, with further rotation of the handle  24 , the lifting force is sufficient to overcome the force retaining the car  4  in its stuck position. The stuck car  4  is thereby released.  
         [0019]      FIG. 4  shows a second embodiment of the present invention wherein a lifting apparatus  60  is secured between T-profile guide rails  50  mounted on the shaft walls  4  to release a car stuck within the shaft  2 . Each guide rail  50  has laterally extending side flanges  52  and a transverse guide blade  54 . The side flanges  52  are affixed to the corresponding side wall  4  through brackets (not shown). The transverse guide blades  54  extend into the shaft  2  to provide a guiding surface for the guide shoes or roller guides (not shown) provided on the car  6 .  
         [0020]     The lifting apparatus  60  comprises an intermediate bar  62  with telescopic end shoes  72  to engage with the opposing guide blades  54 . A conventional lifting device  66  such as a chain block or rope hoist is installed between a lifting eye  64  on the intermediate bar  62  and fastening means  68  on the car  6 .  
         [0021]     As shown in  FIG. 5 , an exploded view of section A in  FIG. 4 , the intermediate bar  62  is received in a sleeve  74  provided in each end shoe  72 . The end shoes  72  are extended outwards from the intermediate bar  62  until they partially envelope the blade  54  of the respective guide rail  50  and adjustment pins  76  are then inserted through the sleeves  74  and adjustment holes  70  in the intermediate bar  62  to lock the arrangement between the opposing guide rails  50 .  
         [0022]      FIG. 6  is a cross-section through line B-B of  FIG. 5  and shows how each end shoe  72  envelopes and subsequently engages with its corresponding guide rail  50 . The housing  78  is generally U-shaped, having a first end limb portion  78   a  and a second tapered limb portion  76   b  defining a channel  80  therebetween. The guide rail blade  54  is accommodated within this channel  80 , which is broader at the bottom than at the top. To secure the locked arrangement of intermediate bar  62  and end shoes  72  to the guide rails  50 , a captive roller  86  is inserted through the bottom of the channel  80  alongside the guide rail blade  54 . As the roller  86  is moved upwards along an inclined surface  84  of the second tapered limb portion  76   b  of the housing  76 , it comes to a point where the channel  80  is only sufficient in width to accommodate the roller  86  and the guide rail blade  54 . At this point the roller  86  and the guide rail blade  54  frictionally engage and become wedged in the channel  80 , and any downward motion of the locked arrangement of intermediate bar  62  and end shoes  72  relative to the guide rail  50  is prevented. Preferably, the inner surface  85  of the first limb portion  78  has a high coefficient of friction.  
         [0023]     With the lifting apparatus  60  installed as discussed above, the user operates the lifting device  66  to lift and release the trapped car  6 . To dismantle the lifting apparatus  60 , the user pulls down on a winged nut  90  connected to an axle  88  of the roller  86 , thereby unfastening the end shoe  72  from the guide rail  50 .  
         [0024]     In the embodiments described above it is assumed that the car  6  is of the self-supporting type. However, it will be apparent to those skilled in the art that the invention can equally be employed for cars supported in a frame wherein the lifting apparatus would be attached to the upper yoke of the car frame rather than the car roof.  
         [0025]     It will also be understood that the invention can be used to release a stuck counterweight, or indeed any equipment within the elevator shaft  2 .  
         [0026]     Furthermore, it will be realised that individual components of the two embodiments described in detail above can be combined to give further variants of the invention. For example, the end shoe housings  78  of the second embodiment could be used to secure the interconnected bars  40  of the first embodiment to the guide rails  50 . In another example, the intermediate bar  62  of the second embodiment could have a threaded hole to engage with the threaded bar  20  of the first embodiment.