Patent Publication Number: US-2012024675-A1

Title: Drive assembly for a passenger conveyor

Description:
BACKGROUND 
     Passenger conveyors such as escalators and moving walkways typically include moving surfaces such as steps that carry passengers between landings at opposite ends of the conveyor. The moving surfaces are propelled by a drive assembly including a motor, a drive sprocket and a step chain. The motor typically causes the drive sprocket to rotate. The step chain is driven by the sprocket. The step chain is secured to the moving surfaces in a manner that results in the desired conveyor operation. 
     Conventional passenger conveyor drive assemblies present various issues. One issue is noise and vibration associated with step chain linkages moving along the path and interacting with the drive sprocket. Another issue is that step chains typically require lubrication, which introduces materials and maintenance issues. Additionally, typical step chain arrangements require maintenance, which introduces additional expense and inconvenience for building owners. 
     SUMMARY 
     An exemplary drive assembly for a passenger conveyor includes a belt including a plurality of cords at least partially encased in a jacket. A plurality of connecting blocks are secured to the belt longitudinally spaced apart from each other along the belt. 
     The various features and advantages of the disclosed example 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  illustrates an example passenger conveyor. 
         FIG. 2  illustrates selected portions of an example passenger conveyor drive assembly. 
         FIG. 3  illustrates other selected portions of an example passenger conveyor drive assembly. 
         FIG. 4  is a cross-sectional illustration of an example connecting block and belt configuration. 
         FIG. 5  is a cross-sectional illustration of another example connecting block and belt configuration. 
         FIG. 6  is a cross-sectional illustration of another example connecting block and belt configuration. 
         FIG. 7  is a cross-sectional illustration of another example connecting block and belt configuration. 
         FIG. 8  is a cross-sectional illustration of another example connecting block and belt configuration. 
         FIG. 9  is a cross-sectional illustration of another example connecting block and belt configuration. 
         FIG. 10  is a cross-sectional illustration of another example connecting block and belt configuration. 
         FIG. 11  is a cross-sectional illustration of another example connecting block and belt configuration. 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 1  shows selected portions of an example passenger conveyor  20 . The illustrated example conveyor  20  is an escalator. Other examples include moving walkways. The conveyor  20  includes a plurality of moving surfaces  22 , which comprise steps in this example. The moving surfaces  22  carry a passenger between landings  24  and  26 . A handrail  28  moves with the moving surfaces  22  to provide a surface for an individual to grasp while being carried by the conveyor  20 . 
     As can be appreciated from  FIGS. 1-3 , the conveyor  20  includes a drive assembly  30  comprising a belt  32  and a plurality of connecting blocks  34  secured to the belt  32 . The connecting blocks  34  are spaced from each other longitudinally along a length of the belt  32 . 
     A drive wheel  40  is rotated by a motor (not illustrated) and imparts a moving force to move the belt  32  and the connecting blocks  34  along a path corresponding to the path followed by the moving surfaces  22 . The connecting blocks  34  cooperate with a correspondingly configured surface or features on the drive wheel  40  such that the connecting blocks  34  are positively engaged by the drive wheel  40  to move them and the belt  32 . In the illustrated example, the connecting blocks  34  are at least partially received within recesses  42  in the drive wheel  40 . In this example, the drive wheel  40  also includes an exterior drive surface  44  that engages the belt  32  directly to propel the belt  32 . In this example, frictional engagement between the drive surface  44  and the belt  32  facilitates moving the belt as desired. 
     The connecting blocks  34  provide a positive driving surface and the belt  32  provides a frictional driving surface for causing desired movement of the belt  32  and the connecting blocks  34 . The moving surfaces are coupled with the belt  32  by a connection between the connecting blocks  34  and axles  46  such that movement of the belt  32  and connecting blocks  34  results in corresponding movement of the moving surfaces  22 . In this example the connecting blocks  34  have interiorly facing connection surfaces that are configured to be connected to the axles  46 . The moving surfaces  22  are connected to the axles  46  using a conventional step-to-axle connection in one example. In another example, the connecting blocks  34  have at least one connection surface configured to be connected directly to a portion of a moving surface  22 . The connecting blocks  34  facilitate coupling the moving surfaces  22  to the belt  32  so that the drive assembly  30  can move the moving surfaces  22  as desired. 
     In the example of  FIG. 3 , the spacing between the connecting blocks  34  corresponds to the pitch of the axles  46 . In another example, not every connecting block is coupled to a moving surface  22  or axle  46 . In such an example some of the connecting blocks serve as positive drive elements without providing a connection between the drive assembly  30  and the moving surfaces  22 . 
     There are various possible configurations of a drive assembly  30  designed according to this invention. One example is shown in  FIG. 4 . This example includes a belt  32  having a plurality of cords  50  that extend longitudinally along the length of the belt  32 . In one example the cords  50  comprise steel. In another example, the cords  50  comprise a polymer. The cords  50  are at least partially covered by a jacket  52 . One example jacket material comprises a urethane such as thermoplastic polyurethane. 
     The connecting blocks  34  in this example include a first portion  54  received against one side of the belt  32  and a second portion  56  received on an oppositely facing side of the belt  32 . In this example, there is one first portion  54  and two second portions  56 . Securing members  58  hold the connecting blocks  34  in their desired positions on the belt  32 . One example includes threaded securing members  58  such as bolts that are received through holes in the belt  32  and are threaded into at least one of the portions  54  or  56 . 
     The connecting blocks in one example comprise metal. One example comprises steel. Some connecting blocks have a polymer coating. Other example connecting blocks comprise hard plastic materials. 
       FIG. 5  shows another example in which there are two first portions  54  spaced from each other. 
       FIG. 6  illustrates another variation in which the second portions  56  have an interior surface arranged at an oblique angle relative to an axis of rotation of the drive wheel  40 . This example also includes securing block portions  60  that are received against exterior surfaces on the first portion  54  and the second portions  56 . The securing members  58  are not received through the belt  32  in this example as can be appreciated from the drawing. 
     The example of  FIG. 7  is similar to that of  FIG. 4  but has the additional securing block portions  60  and securing member  58  received on the opposite sides of the belt  32 . In  FIG. 8  the first portion  54  and the second portions  56  extend laterally outward considerably further than the outside dimension of the jacket  52  of the belt  32 . In this embodiment, the securing members  58  are secured to at least one of the portions  54  and  56 , but are not received through the belt  32 . 
       FIG. 9  shows another example drive assembly arrangement in which two belts  32 A and  32 B are included. In this example, a spacer  70  is placed between the belts  32 A and  32 B at the locations of the connecting blocks  34 . Using multiple belts can increase the load bearing capacity of the drive assembly. Such an example may be particularly well-suited for use in a passenger conveyor having a relatively longer run, for example. 
       FIG. 10  shows another multiple belt example. The two belts  32 A and  32 B are side-by-side in this example (instead of being stacked together as in the example of  FIG. 9 ). The greater width of the driving surface  44  in this example provides sufficient frictional engagement with both belts  32 A and  32 B. 
     In each of the examples of  FIGS. 4 through 10 , at least some of the surface of the belt  32  is exposed facing the exterior drive surface  44  on the drive wheel along the entire length of the belt  32 . These examples provide for frictional driving engagement between the drive wheel  40  and the belt  32  wherever the belt  32  wraps about the drive wheel  40 . 
     In the example of  FIG. 11 , the belt  32  has an at least partially V-shaped cross section and the drive surface  44  has a corresponding V-shaped configuration such that there is frictional engagement between three surfaces at the interface between the belt  32  and the drive surface  44 . 
     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.