Abstract:
A belt for suspending and/or driving an elevator car extending longitudinally along a length of the belt. An inner belt layer formed from a first material is bonded to the plurality of tension elements at a first side of the belt. The inner belt layer forms an inner belt surface interactive with a traction sheave of an elevator system. An outer belt layer formed from a second material is bonded to the plurality of tension elements at a second side of the belt. The plurality of tension elements are located between the first side and the second side.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    The subject matter disclosed herein relates to belts utilized in elevator systems for suspension and/or driving of the elevator car and/or counterweight. 
         [0002]    Conventional elevator systems use rope formed from steel wires as a lifting tension load bearing member. Other systems utilize a lifting belt formed from a number of steel cords, formed from steel wires, retained in an elastomeric jacket. The cords act as the load supporting tension member, while the elastomeric jacket holds the cords in a stable position relative to each other, and provides a frictional load path to provide traction for driving the belt. 
         [0003]    More recent developments in the area of composites include the use synthetic fibers such as carbon fiber and glass fiber to provide a higher strength to weight ratio than steel. The fibers are first impregnated with thermoset resins and then cured to form rigid and brittle composite cords that are later surrounded with an elastomer to provide traction for the belt. Although a belt with carbon fiber and thermoset resin will provide improved strength to weight advantages compared to steel cord belt, significant manufacturing, performance and durability challenges exist. For example, the long curing cycle of the thermoset resin and entrapment of air voids during cure present a manufacturing challenge. Further, the rigid construction is contrary to the desire for a flexible belt capable of many thousands of bending cycles without brittle or fatigue failure in the field. 
       BRIEF DESCRIPTION OF THE INVENTION 
       [0004]    In one embodiment, a belt for suspending and/or driving an elevator car includes a plurality of tension elements extending longitudinally along a length of the belt. An inner belt layer formed from a first material is bonded to the plurality of tension elements at a first side of the belt. The inner belt layer forms an inner belt surface interactive with a traction sheave of an elevator system. An outer belt layer formed from a second material is bonded to the plurality of tension elements at a second side of the belt. The plurality of tension elements are located between the first side and the second side. 
         [0005]    Additionally or alternatively, in this or other embodiments, the first material is different from the second material. 
         [0006]    Additionally or alternatively, in this or other embodiments, the tension elements include steel cords, carbon fiber, polymer fiber and/or glass fiber. 
         [0007]    Additionally or alternatively, in this or other embodiments, the plurality of tension elements are at least partially enclosed in a matrix material. 
         [0008]    Additionally or alternatively, in this or other embodiments, the inner belt layer includes a tape including the first material. 
         [0009]    Additionally or alternatively, in this or other embodiments, the outer belt layer includes a tape including the second material. 
         [0010]    Additionally or alternatively, in this or other embodiments, the inner belt layer and/or the outer belt layer are thermally bonded to the plurality of tension elements. 
         [0011]    Additionally or alternatively, in this or other embodiments, the first material is one of high performance polymer fibers such as highly oriented thermoplastics (i.e. Dyneema®), aramids (i.e. Kevlar®,), aromatic polyethers (i.e. PEEK, PEKK) or polyimides to enhance abrasive and wear resistance of the inner surface. 
         [0012]    Additionally or alternatively, in this or other embodiments, the second material is selected to enhance one or more of moisture or UV resistance, fire resistance or vibration damping of the belt. 
         [0013]    In another embodiment, a method of forming a belt for suspending and/or driving an elevator car includes arranging a plurality of tension elements to extend longitudinally along a belt length. An inner belt layer comprising a first material is applied to a first side of the plurality of tension elements to form an inner belt surface. An outer belt layer comprising a second material different from the first material is applied to a second side of the plurality of tension elements forming an outer belt surface. The plurality of tension elements are located between the inner belt surface and the outer belt surface. 
         [0014]    Additionally or alternatively, in this or other embodiments, the plurality of tension elements are at least partially enclosed in a matrix material prior to applying the inner layer and/or the outer layer. 
         [0015]    Additionally or alternatively, in this or other embodiments, the tension elements include steel cords, carbon fiber and/or glass fiber. 
         [0016]    Additionally or alternatively, in this or other embodiments, the inner belt layer includes a tape including the first material. 
         [0017]    Additionally or alternatively, in this or other embodiments, the outer belt layer includes a tape including the second material. 
         [0018]    Additionally or alternatively, in this or other embodiments, the inner belt layer and/or the outer belt layer are thermally bonded to the plurality of tension elements. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0019]      FIG. 1A  is a schematic of an exemplary elevator system having a 1:1 roping arrangement; 
           [0020]      FIG. 1B  is a schematic of another exemplary elevator system having a different roping arrangement; 
           [0021]      FIG. 1C  is a schematic of another exemplary elevator system having a cantilevered arrangement; 
           [0022]      FIG. 2  is a cross-sectional view of an embodiment of an elevator belt; and 
           [0023]      FIG. 3  is schematic view of an embodiment of a manufacturing process for an elevator belt. 
       
    
    
       [0024]    The detailed description explains the invention, together with advantages and features, by way of examples with reference to the drawings. 
       DETAILED DESCRIPTION OF THE INVENTION 
       [0025]    Shown in  FIGS. 1A, 1B and 1C  are schematics of exemplary traction elevator systems  10 . Features of the elevator system  10  that are not required for an understanding of the present invention (such as the guide rails, safeties, etc.) are not discussed herein. The elevator system  10  includes an elevator car  12  operatively suspended or supported in a hoistway  14  with one or more belts  16 . The one or more belts  16  interact with one or more sheaves  18  to be routed around various components of the elevator system  10 . The one or more belts  16  could also be connected to a counterweight  22 , which is used to help balance the elevator system  10  and reduce the difference in belt tension on both sides of the traction sheave during operation. 
         [0026]    The sheaves  18  each have a diameter  20 , which may be the same or different than the diameters of the other sheaves  18  in the elevator system  10 . At least one of the sheaves could be a traction sheave  52 . The traction sheave  52  is driven by a machine  50 . Movement of drive sheave by the machine  50  drives, moves and/or propels (through traction) the one or more belts  16  that are routed around the traction sheave  52 . 
         [0027]    At least one of the sheaves  18  could be a diverter, deflector or idler sheave. Diverter, deflector or idler sheaves are not driven by a machine  50 , but help guide the one or more belts  16  around the various components of the elevator system  10 . 
         [0028]    In some embodiments, the elevator system  10  could use two or more belts  16  for suspending and/or driving the elevator car  12 . In addition, the elevator system  10  could have various configurations such that either both sides of the one or more belts  16  engage the one or more sheaves  18  (such as shown in the exemplary elevator systems in  FIGS. 1A, 1B or 1C ) or only one side of the one or more belts  16  engages the one or more sheaves  18 . 
         [0029]      FIG. 1A  provides a 1:1 roping arrangement in which the one or more belts  16  terminate at the car  12  and counterweight  22 .  FIGS. 1B and 1C  provide different roping arrangements. Specifically,  FIGS. 1B and 1C  show that the car  12  and/or the counterweight  22  can have one or more sheaves  18  thereon engaging the one or more belts  16  and the one or more belts  16  can terminate elsewhere, typically at a structure within the hoistway  14  (such as for a machineroomless elevator system) or within the machine room (for elevator systems utilizing a machine room. The number of sheaves  18  used in the arrangement determines the specific roping ratio (e.g. the 2:1 roping ratio shown in  FIGS. 1B and 1C  or a different ratio).  FIG. 1C  also provides a so-called rucksack or cantilevered type elevator. The present invention could also be used on elevator systems other than the exemplary types shown in  FIGS. 1A, 1B and 1C . 
         [0030]    The belts  16  are constructed to have sufficient flexibility when passing over the one or more sheaves  18  to provide low bending stresses, meet belt life requirements and have smooth operation, while being sufficiently strong to be capable of meeting strength requirements for suspending and/or driving the elevator car  12 . 
         [0031]      FIG. 2  provides a schematic of an exemplary belt  16  construction or design. The belt  16  includes a plurality of tension elements  32  extending longitudinally along the belt  16 . The tension elements  32  may be cords formed from steel wires, or may be formed from other materials such as carbon fiber, polymer fiber such as aramid fiber and/or glass fiber. The tension elements  32  are arrayed laterally across a width  34  of the belt  16  and, as stated above, extend longitudinally along a belt length. In some embodiments, a binder or matrix  36  is disposed around the tension elements  32  to retain the tension elements  32  in selected positions relative to each other. In some embodiments, the matrix  36  is formed from a thermoplastic polymer such as nylon, PP (polypropylene), PET (polyethylene terephthalate), PEI (polyetherimide), or PEEK (polyether ether ketone). Fillers and/or modifiers may be added to the matrix  36  to enhance select properties of the matrix such as strength, durability, and/or frictional properties. 
         [0032]    The belt  16  construction is a laminate construction, with the tension elements  32  disposed at a middle portion  38  of the belt  16 , in some embodiments substantially at a center of the belt  16 , and layers of additional material disposed on the tension element  32  layer to form the remainder of the belt  16 . This construction of the belt  16  allows for use of different materials in discrete layers of the belt  16 , and selection of those materials based on selected properties for those layers. For example, in the embodiment shown in  FIG. 2 , one or more inner layers  40  forming an inner or traction surface  42  of the belt  16 , are applied to the tension members  32  and are formed from materials selected for their abrasive and wear resistance as the traction surface  42  interacts with the traction sheave  52  to drive the elevator system  10 . Materials suitable for the inner layers  40  include performance polymer such as highly oriented thermoplastics (i.e. Dyneema®), aramids (i.e. Kevlar®), aromatic polyethers (i.e. PEEK, PEKK) polyimides, urethanes and other abrasion resistant polymers. 
         [0033]    In the middle portion  38  of the belt  16  a number of middle layers  44  may be included, in addition to or instead of the tension elements  32 . The middle layers  44  are formed form materials having high stiffness and high strength, especially high tensile strength. Materials utilized for the middle layers  44  include carbon fiber. In addition, the carbon fiber material would utilize fine fibers to maintain high tensile stiffness of the middle layers  44  while having relatively low bending stiffness to prevent the belt  16  from having a high rigidity. 
         [0034]    The belt  16  also includes one or more outer layers  46 , forming an outer surface  48  opposite the traction surface  42 . The outer layers  46  may be formed from the same materials as the inner layers  40 , or alternatively may be formed from other materials that are, for example, more cost effective than those of the inner layers  40 , or materials having other properties to enhance performance of the belt  16 . For example, the outer layers  46  may be formed of materials providing environmental protection such as moisture or UV resistance, or fire resistance or vibration damping. Materials that may be utilized for fire resistance include fiberglass mesh, Kevlar® or aluminum mesh. It is to be appreciated that such environmental protection materials may also be utilized in the inner layers  40 . In addition to or instead of environmental protection, the outer layers  46  may include materials or sensors  54  embedded therein to monitor the health or condition of the tension elements  32 . The sensors  54  may periodically transmit information regarding the condition of the tension elements  32  to a control system (not shown). 
         [0035]    Referring now to  FIG. 3 , a schematic illustration of a manufacturing process for a belt  16  is illustrated. Each layer  40 ,  44 ,  46  is formed using preformed tapes, with the functional material of the layer formed into the tape with a tape matrix material. As with matrix  36 , the tape matrix material may be a thermoplastic polymer such as nylon, PP, PET, PEI or PEEK. The tapes are then consolidated into the belt  16  as shown by a continuous manufacturing process. The process utilizes one or more sets of forming rollers  56  through which the tapes forming layers  40 ,  44  and  46 , along with tension members  32  are passed. The rollers  56  apply pressure to the structure. To cure the belt  16  in embodiments here the tape matrix is a thermoplastic polymer, for example, the structure is then heated to adhere the layers  40 ,  44 ,  46  to each other. In other embodiments, adhesives or other means may be utilized to adhere the layers  40 ,  44 ,  46  to each other. 
         [0036]    The structure and manufacturing process of the belt  16  disclosed herein allows for tailor of belt  16  properties to achieve a wide variety of functional requirements, and in some embodiments allows for health monitoring of the belt. The materials may be selected to improve functional life of the belt  16 . Each layer of the belt may be tailored for specific requirements without significant changes to the manufacturing process or to other layers of the belt. Further, the continuous manufacturing process reduces manufacturing cost of the belt. 
         [0037]    While the invention has been described in detail in connection with only a limited number of embodiments, it should be readily understood that the invention is not limited to such disclosed embodiments. Rather, the invention can be modified to incorporate any number of variations, alterations, substitutions or equivalent arrangements not heretofore described, but which are commensurate with the spirit and scope of the invention. Additionally, while various embodiments of the invention have been described, it is to be understood that aspects of the invention may include only some of the described embodiments. Accordingly, the invention is not to be seen as limited by the foregoing description, but is only limited by the scope of the appended claims.