Patent Publication Number: US-11040859-B2

Title: Frameless elevator counterweight

Description:
BACKGROUND 
     Elevator systems are useful for carrying passengers and items between different levels in a building. Different configurations of elevator systems have been used for many years. One type of elevator system configuration relies upon traction between a drive sheave or traction sheave and the load bearing members, such as round steel ropes or flat belts, that support the elevator car and a counterweight. In such elevator systems, movement of the traction sheave results in movement of the load bearing members and corresponding movement of the elevator car. 
     Counterweights are provided in elevator systems for known reasons. One issue associated with many counterweights is that they tend to be expensive and space-inefficient. Typical counterweights require separate provisions for guides to follow along guiderails, filler weight retention and alignment, connection with the roping assembly, and significant structural provision to retain all of the weight. Additionally, heavier counterweights tend to require larger frames which require even more space. Adding hoistway space to accommodate a larger counterweight tends to add significant cost because that requires a deeper pit, higher overhead clearance, a wider hoistway, or a combination of them. Further, more expensive structural materials are often used for larger sized counterweights. 
     SUMMARY 
     An illustrative example embodiment of an elevator counterweight includes a frameless stack of a plurality of weights that are connected to maintain a vertical and horizontal alignment of the weights. A plurality of guides are directly supported on at least some of the weights. The plurality of guides are configured to guide movement of the counterweight along elevator guide rails. 
     In an example embodiment having one or more features of the elevator counterweight of any of the previous paragraphs, the plurality of weights includes a top weight and a bottom weight. The top weight and the bottom weight each include lateral edges. At least one of the guides is supported near one of the lateral edges, respectively, of the top weight. At least one of the guides is supported near one of the lateral edges, respectively, of the bottom weight. 
     In an example embodiment having one or more features of the elevator counterweight of any of the previous paragraphs, a portion of each of the guides extends laterally beyond the lateral edges. 
     In an example embodiment having one or more features of the elevator counterweight of any of the previous paragraphs, the weights respectively include a channel on each of two oppositely facing lateral edges, the channels are aligned vertically and the channels are configured to receive a portion of an elevator guiderail within the channel. 
     In an example embodiment having one or more features of the elevator counterweight of any of the previous paragraphs, the guides are at least partially situated within the channel of the at least some of the weights. 
     In an example embodiment having one or more features of the elevator counterweight of any of the previous paragraphs, the guides respectively comprise a piece of low friction material secured to the at least some of the weights within the channels. 
     In an example embodiment having one or more features of the elevator counterweight of any of the previous paragraphs, the guides extend along an entire height of the channels. 
     In an example embodiment having one or more features of the elevator counterweight of any of the previous paragraphs, the guides at least partially secure the weights in the horizontal alignment. 
     In an example embodiment having one or more features of the elevator counterweight of any of the previous paragraphs, the weights each include an opening through the weight and the counterweight comprises a tie rod received at least partially in the openings, the tie rod securing the weights in the vertical and horizontal alignment. 
     In an example embodiment having one or more features of the elevator counterweight of any of the previous paragraphs, the weights respectively comprise at least one of a boss and a recess. The bosses are sized to be received into the recesses. The boss on one of the weights is received into the recess on another one of the weights to securely interconnect the ones of the weights together. 
     In an example embodiment having one or more features of the elevator counterweight of any of the previous paragraphs, the weights respectively comprise at least one of a lug and a recess. The recesses are sized to receive at least a portion of the lugs. The lug on one of the weights is received into the recess on another one of the weights to securely interconnect the ones of the weights together. 
     In an example embodiment having one or more features of the elevator counterweight of any of the previous paragraphs, the lugs extend at least partially from a lateral edge of the weights and the recesses are at least partially formed along a lateral edge of the weights. 
     An example embodiment having one or more features of the elevator counterweight of any of the previous paragraphs includes at least one sheave supported on at least one of the weights, the sheave being rotatable relative to the at least one of the weights about an axis that remains stationary relative to the at least one of the weights. 
     An illustrative example embodiment of an elevator system includes the elevator counterweight of any of the previous paragraphs. 
     An example embodiment having one or more features of the elevator system of any of the previous paragraphs includes at least one guiderail and wherein the weights respectively include a channel that is configured to receive at least a portion of the guiderail. 
     In an example embodiment having one or more features of the elevator system of any of the previous paragraphs, the guides are secured at least partially within the recess of at least two of the weights and the guides contact the portion of the guiderail. 
     In an example embodiment having one or more features of the elevator system of any of the previous paragraphs, the guides comprise pieces of low friction material lining the recesses of all of the weights. The guides at least partially secure the weights in the horizontal alignment. 
     In an example embodiment having one or more features of the elevator system of any of the previous paragraphs, the at least one guiderail comprises two guiderails, the guiderails are situated on opposite sides of the weights, the guiderails are spaced apart a first distance and the weights include lateral edges that are spaced apart a second distance that is greater than the first distance. 
     In an example embodiment having one or more features of the elevator system of any of the previous paragraphs, the weights are secured together by at least one of cooperating bosses or lugs and correspondingly shaped recesses on the weights or tie rods received at least partially through an opening in the weights. 
     An example embodiment having one or more features of the elevator system of any of the previous paragraphs includes at least one sheave supported on at least one of the weights, the sheave being rotatable relative to the at least one of the weights about an axis that remains stationary relative to the at least one of the weights. 
     The various features and advantages of at least one disclosed example embodiment will become apparent to those skilled in the art from the following detailed description. The drawings that accompany the detailed description can be briefly described as follows. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  schematically illustrates selected portions of an elevator system including an elevator counterweight designed according to an embodiment of this invention. 
         FIG. 2  schematically illustrates an example arrangement of connecting features for securing weights together. 
         FIG. 3  schematically illustrates another example arrangement of securing features to secure weights together. 
         FIG. 4  illustrates a selected feature of an example embodiment from a first perspective. 
         FIG. 5  illustrates the feature shown in  FIG. 4  from another perspective. 
         FIG. 6  illustrates another frameless counterweight configuration designed according to an embodiment of this invention. 
         FIG. 7  illustrates selected features of the embodiment shown in  FIG. 6 . 
     
    
    
     DETAILED DESCRIPTION 
     Embodiments of this invention include frameless counterweights that make efficient use of space and offer the capability to realize a heavier counterweight in an economical manner. 
       FIG. 1  schematically illustrates selected portions of an elevator system  20 . An elevator car  22  and counterweight  24  are situated within a hoistway  26 . A plurality of load bearing members  28 , such as round steel ropes or flat belts, support the elevator car  22  and counterweight  24 . A machine  30 , which includes a motor and brake, controls movement of a traction sheave  32  to control movement of the load bearing members  28 , which controls movement of the elevator car  22  and counterweight  24 . Counterweight guiderails  34  are illustrated in  FIG. 1  but guiderails for the elevator car  22  are not shown. Those skilled in the art will understand that more components are required in the elevator system  20 , such as elevator car guiderails. 
     The counterweight  24  is frameless and includes a plurality of weights  40  in a stack. The weights  40  are connected together in a way that maintains a vertical and horizontal alignment between the weights  40  without requiring an external frame. In the example of  FIG. 1 , a sheave  42  is supported beneath the stack of weights  40  in an underslung manner. An underslung configuration, such as that shown in the example of  FIG. 1 , contributes to eliminating a need for a structural frame for the counterweight  24 , in part, because the sheave  42  effectively supports the stack of weights  40  and the load bearing members  28  are beneath the sheave  42 . 
       FIG. 2  illustrates one example way in which the weights  40  are connected together. Each of the weights  40  in this example includes at least one boss  44  and at least one correspondingly shaped recess  46 . The bosses  44  on one of the weights  40  are received into the recesses  46  on an adjacent one of the weights  40  when the stack of weights  40  are assembled. 
       FIG. 3  illustrates another arrangement for securing the weights  40  together. This example includes a plurality of lugs  50  and recesses  52 . The lugs  50  are received into corresponding recesses  52  to secure the weights  40  to each other. When the weights  40  are secured to each other using features like those shown in  FIGS. 2 and 3 , the weights  40  remain in a desired vertical and horizontal alignment with each other without requiring an external frame to hold the weights  40  in appropriate positions. 
     As shown in  FIGS. 4 and 5 , the illustrated example embodiment of the counterweight  24  includes recesses  56  that receive guides  58 , which facilitate movement of the counterweight  24  along the guiderails  34 . The recesses  56  extend inward toward a center of the weights  40  on lateral edges  60  of each weight  40 . The guides  58  in some embodiments are received in only some of the weights  40 . In the example illustration of  FIG. 5 , the guides  58  extend along an entire length or height of the stack of weights  40 . In some such arrangements, the guides  58  have sufficient stiffness or rigidity to contribute to maintaining the horizontal alignment of the weights  40 . 
     The guides  58  in the illustrated example embodiment comprise a strip or sheet of low friction material for sliding along a portion of the guiderails  34 . Other embodiments include guides that have rollers that follow along the guiderails  34 . 
     One feature of the example embodiment shown in  FIGS. 4 and 5  is that a spacing S between the guiderails  34  is smaller than a width W or spacing between the lateral edges  60  of the weights  40 . This configuration allows for a portion of the weights  40  to extend horizontally further outward than the spacing S between the guiderails  34 . This configuration is different than counterweights that include a frame, in part, because the frame typically has to occupy space between the guiderails, which requires the filler weights to be even smaller. With the illustrated example embodiment, on the other hand, the weights  40  can be wider making more efficient use of space within the hoistway because more weight per unit height can be incorporated into the counterweight  24  compared to framed counterweight designs. 
       FIGS. 6 and 7  illustrate another example embodiment of a counterweight  24 ′. In this embodiment, the weights  40  include guides  64  situated near the lateral edges  60  of a top weight plate  70  and a bottom weight plate  72 . The guides  64  in this example extend beyond the lateral edges  60  of the weights  40 . The weights  40  in this embodiment also include recesses  56  configured to receive at least a portion of the guiderails  34 , respectively. Again, the ability to have portions of the weights  40  situated further apart than the spacing S between the guiderails  34  makes more efficient use of space within the hoistway  26  and allows for realizing heavier counterweights without requiring excessive height. 
     The bottom weight plate  72  in this example includes supports  66  that support the sheave  42  in an underslung configuration. In another embodiment configured similar to that shown in  FIGS. 6 and 7 , the supports  66  for the sheave  42  are secured to the top weight plate  70 . 
     As shown in  FIGS. 6 and 7 , tie rods  78  are received through openings  80  in the weights  40 . The tie rods  78  secure the weights  40  together to maintain a vertical and horizontal alignment of them. Tie rods  78  may be used in combination with other connecting features, such as those shown in  FIGS. 2 and 3 . 
     The illustrated embodiments and others allow for realizing the required functionality of a counterweight within an elevator system without requiring a frame that surrounds and supports filler weights. Instead, the weights  40  are in a frameless stack on which the guides  58 ,  64  are directly supported. Additionally, the components for suspending the counterweight  24  within the hoistway  26  are incorporated onto or connected to at least one of the weights without requiring separate frame components. 
     While different embodiments are illustrated and described above, the various features of them are not limited to the particular embodiment shown. Variations and combinations other than those illustrated are possible to realize other embodiments. In other words, one or more features of each of the illustrated embodiments may be combined with one or more features of another embodiment. 
     The preceding description is exemplary rather than limiting in nature. Variations and modifications to the disclosed examples may become apparent to those skilled in the art that do not necessarily depart from the essence of this invention. The scope of legal protection given to this invention can only be determined by studying the following claims.