Patent Publication Number: US-2023159303-A1

Title: Belt with layered load bearing elements

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of U.S. application Ser. No. 16/055,596, filed Aug. 6, 2018, the disclosure of which in incorporated herein by reference in its entirety. 
     BACKGROUND 
     Embodiments disclosed herein relate to elevator systems, and more particularly, to a load bearing member configured for use in an elevator system. 
     Elevator systems are useful for carrying passengers, cargo, or both, between various levels in a building. Some elevators are traction based and utilize load bearing tension members such as ropes or belts for supporting the elevator car and achieving the desired movement and positioning of the elevator car. 
     Where ropes are used as tension members, each individual rope is not only a traction device for transmitting the pulling forces but also participates directly in the transmission of the traction forces. Where belts are used as a tension member, a plurality of load bearing elements are embedded in a common elastomer belt body. The load bearing tension elements are exclusively responsible for transmitting the pulling forces, while the elastomer material transmits the traction forces. Due to their light weight and high strength, load bearing tension members formed from unidirectional fibers arranged in a rigid matrix composite provide significant benefits when used in elevator systems, particularly high rise systems. However, the unidirectional composite construction results in a high bending stiffness which can produce substantial bending stress when used in an elevator system where the load bearing tension member is wrapped around a traction sheave. 
     BRIEF DESCRIPTION 
     In one embodiment, a load bearing tension member for an elevator system includes a plurality of tension elements arrayed across a tension member width. The tension elements are offset from a tension member central axis, the central axis bisecting a tension member thickness and extending across the tension member width. The tension elements include a plurality of fibers extending along a length of the tension element, and a matrix material in which the plurality of fibers are embedded. A jacket at least partially encapsulates the plurality of tension elements. 
     Additionally or alternatively, in this or other embodiments, the plurality of tension elements are at least two tension elements arranged symmetrically about the tension member central axis, with a first tension element located at a first side of the tension member central axis and a second tension element located at a second side of the tension element. 
     Additionally or alternatively, in this or other embodiments the first tension member and the second tension member are separated by a separator layer of jacket material. 
     Additionally or alternatively, in this or other embodiments the plurality of tension elements are alternatingly staggered relative to the tension member central axis, along the tension member width. 
     Additionally or alternatively, in this or other embodiments the plurality of tension elements are arrayed such that a center of each tension member is positioned along a preselected arc. 
     Additionally or alternatively, in this or other embodiments the plurality of fibers includes one or more of carbon, glass, aramid, nylon, or polymer fibers. 
     Additionally or alternatively, in this or other embodiments the plurality of fibers includes steel fibers. 
     Additionally or alternatively, in this or other embodiments the tension elements have a rectangular or circular cross-section. 
     Additionally or alternatively, in this or other embodiments the jacket is formed from an elastomeric material. 
     Additionally or alternatively, in this or other embodiments the matrix material is a polyurethane, vinylester, or epoxy material. 
     In another embodiment, an elevator system includes a hoistway, an elevator car movable along the hoistway, and one or more tension members operably connected to the elevator car to move the elevator car along the hoistway. A tension member of the one or more tension members includes a plurality of tension elements arrayed across a tension member width. The tension elements are offset from a tension member central axis, the central axis bisecting a tension member thickness and extending across the tension member width. The tension elements include a plurality of fibers extending along a length of the tension element, and a matrix material in which the plurality of fibers are embedded. A jacket at least partially encapsulates the plurality of tension elements. 
     Additionally or alternatively, in this or other embodiments the plurality of tension elements are at least two tension elements arranged symmetrically about the tension member central axis, with a first tension element located at a first side of the tension member central axis and a second tension element located at a second side of the tension element. 
     Additionally or alternatively, in this or other embodiments the first tension member and the second tension member are separated by a separator layer of jacket material. 
     Additionally or alternatively, in this or other embodiments the plurality of tension elements are alternatingly staggered relative to the tension member central axis, along the tension member width. 
     Additionally or alternatively, in this or other embodiments the plurality of tension elements are arrayed such that a center of each tension member is positioned along a preselected arc. 
     Additionally or alternatively, in this or other embodiments the preselected arc matches a sheave crown of the elevator system. 
     Additionally or alternatively, in this or other embodiments the plurality of fibers includes one or more of carbon, glass, aramid, nylon, or polymer fibers. 
     Additionally or alternatively, in this or other embodiments the plurality of fibers includes steel fibers. 
     Additionally or alternatively, in this or other embodiments the tension elements have a rectangular or circular cross-section. 
     Additionally or alternatively, in this or other embodiments the matrix material is a polyurethane, vinylester, or epoxy material. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The following descriptions should not be considered limiting in any way. With reference to the accompanying drawings, like elements are numbered alike: 
         FIG.  1    is a schematic view of an embodiment of an elevator system; 
         FIG.  2    is a cross-sectional view of an embodiment of a load bearing tension member of an elevator system; 
         FIG.  3    is a cross-sectional view of an embodiment of a tension element for a tension member of an elevator system; 
         FIG.  4    is a cross-sectional view of another embodiment of a load bearing tension member of an elevator system; 
         FIG.  5    is a cross-sectional view of yet another embodiment of a load bearing tension member of an elevator system; and 
         FIG.  6    is a cross-sectional view of still another embodiment of a load bearing tension member of an elevator system. 
     
    
    
     DETAILED DESCRIPTION 
     A detailed description of one or more embodiments of the disclosed apparatus and method are presented herein by way of exemplification and not limitation with reference to the Figures. 
     Shown in  FIG.  1    is a schematic view of an exemplary traction elevator system  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  14  operatively suspended or supported in a hoistway  12  with one or more load bearing tension members, for example belts  16 . The one or more belts  16  interact with sheaves  18  and  52  to be routed around various components of the elevator system  10 . Sheave  18  is configured as a diverter, deflector or idler sheave and sheave  52  is configured as a traction sheave, driven by a machine  50 . Movement of the traction sheave  52  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 . Diverter, deflector or idler sheaves  18  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 . 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. The sheaves  18  and  52  each have a diameter, which may be the same or different from each other. 
     In some embodiments, the elevator system  10  could use two or more belts  16  for suspending and/or driving the elevator car  14  In addition, the elevator system  10  could have various configurations such that either both sides of the one or more belts  16  engage the sheaves  18 ,  52  or only one side of the one or more belts  16  engages the sheaves  18 ,  52 . The embodiment of  FIG.  1    shows a  1 : 1  roping arrangement in which the one or more belts  16  terminate at the car  14  and counterweight  22 , while other embodiments may utilize other roping arrangements. 
     The belts  16  are constructed to 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  14  and counterweight  22 . 
       FIG.  2    provides a cross-sectional schematic of an exemplary belt  16  construction or design. The belt  16  includes a plurality of tension elements  24  extending longitudinally along the belt  16  and arranged across a belt width  26 . The tension elements  24  are at least partially enclosed in a polymeric jacket  28  to restrain movement of the tension elements  24  in the belt  16  with respect to each other and to protect the tension elements  24 . The jacket  28  defines a traction side  30  configured to interact with a corresponding surface of the traction sheave  52 . A primary function of the jacket  28  is to provide a sufficient friction between the belt  16  and the traction sheave  52  to produce a desired amount of traction therebetween. The jacket  28  should also transmit the traction loads to the tension elements  24 . In addition, the jacket  28  should be wear resistant and protect the tension elements  24  from impact damage, exposure to environmental factors, such as chemicals, for example. Exemplary materials for the jacket  28  include the elastomers of thermoplastic and thermosetting polyurethanes, polyaramid, and rubber, for example. Other materials may be used to form the jacket  28  if they are adequate to meet the required functions of the belt  16 . 
     The belt  16  has a belt width  26  and a side belt thickness  32 , with an aspect ratio of belt width  26  to belt thickness  32  greater than one. The belt  16  further includes a back side  34  opposite the traction side  30  and belt edges  36  extending between the traction side  30  and the back side  34 . While sides  32  and  36  are illustrated as flat surfaces, other shapes of sides  32  and  36 , for example, fully or partially convex or concave, may be used in other embodiments. While six tension elements  24  are illustrated in the embodiment of  FIG.  2   , other embodiments may include other numbers of tension elements  24 , for example, 4, 10 or 12 tension elements  24 . Further, while the tension elements  24  of the embodiment of  FIG.  2    are substantially identical, in other embodiments, the tension elements  24  may differ from one another. 
     An exemplary tension element  24  is illustrated in  FIG.  3   . The tension element  24  includes a plurality of load bearing fibers  38  suspended in a matrix material  40 . Exemplary load bearing fibers  38  used to form a tension element  24  include, but are not limited to, carbon, glass, aramid, nylon, and polymer fibers for example. Each of the fibers  38  within a single tension element  24  may be substantially identical or may vary. In addition, the matrix material  40  may be formed from any suitable material, such as polyurethane, vinylester, and epoxy for example. The materials of the fibers  38  and matrix material  40  are selected to achieve a desired stiffness and strength of the belt  16 . 
     In some embodiments, the tension elements  24  are formed as thin layers, in some embodiments by a pultrusion process. In a standard pultrusion process, the fibers  38  are impregnated with the matrix material  40  and are pulled through a heated die and additional curing heaters where the matrix material  40  undergoes cross linking. A person having ordinary skill in the art will understand that controlled movement and support of the pulled fibers may be used to form a desired linear or curved profile of the untensioned belt  16 . It is to be appreciated that in some embodiments, other fibers  38  such as steel fibers may be embedded in the matrix material  40 . 
     Referring again to  FIG.  2   , the tension elements  24  are arranged to reduce bending resistance of the belt  16 , to allow for use of smaller sheave  18 ,  52  diameters, thereby reducing space occupied by the elevator system  10 . The belt  16  has a central belt axis  42  extending across the belt width  26  and bisecting the belt thickness  32 . Tension elements  24  are arranged, not at the central belt axis  42 , but symmetrically about the central belt axis  42  with equal numbers of tension elements  24  on each side of the central belt axis  42 . The tension elements  24  are separated by a separator layer  44  of, for example, jacket  28  material. 
     Referring now to  FIG.  4   , in some embodiments, the tension elements  24  are alternatingly staggered about the central belt axis  42 , with alternating tension elements  24  located mostly, or entirely, at a first side  46  of the central belt axis  42  and at a second side  48  of the central belt axis  42 . Further, referring now to  FIG.  5   , the tension elements  24  may take other shapes, such as circular as shown, or oval or other shapes. 
     Another embodiment is illustrated in  FIG.  6   . In this embodiment, the traction sheave  52  has a crowned sheave surface  54 . In some embodiments the crown is a constant crown radius  56 . In the belt  16 , the tension elements  24  are arrayed across the belt  16  in a pattern defined by a tension element curve  58 . Each tension element center of the tension elements  24  is located along the tension element curve  58 . In the embodiment shown the tension element curve  58  is defined by a tension element radius  60 , which is equal to the crown radius  56 , but inverted relative to the crown radius  56 . This arrangement has the technical effect of equalizing loads on the tension elements  24  regardless of their position along the belt width  26 . 
     The term “about” is intended to include the degree of error associated with measurement of the particular quantity based upon the equipment available at the time of filing the application. 
     The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the present disclosure. As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises” and/or “comprising,” when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, element components, and/or groups thereof. 
     While the present disclosure has been described with reference to an exemplary embodiment or embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the present disclosure. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the present disclosure without departing from the essential scope thereof. Therefore, it is intended that the present disclosure not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this present disclosure, but that the present disclosure will include all embodiments falling within the scope of the claims.