Patent Application
20180208436
The subject matter disclosed herein relates to elevator systems. More particularly, the present disclosure relates to termination of suspension members of elevator systems.
A typical elevator system includes an elevator car, suspended by one or more suspension members, typically a rope or belt, that moves along a hoistway. The suspension member includes one or more tension members and is routed over one or more sheaves, with one sheave, also known as a drive sheave, operably connected to a machine. The machine drives movement of the elevator car via interaction of the drive sheave with the suspension member. The elevator system further typically includes a counterweight interactive with the suspension member. One or more of the ends of the suspension member are terminated, or retained in the hoistway.
Elevator rope or belt terminations typically rely on the ability to either wrap the rope or belt around a wedge, or the ability to spread the individual wires of the rope and create a knob by placing the spread wires into a socket and potting with a material such as a babbitt or epoxy-based potting compound. These typical methods do not work for suspension members that utilize tension members formed from or including unidirectional fibers in a rigid matrix. In such an arrangement, the tension member will fracture if bent around a typical wedge radius, and the fibers are not able to be spread and bent to be utilized in the potted arrangement. Methods of terminating the suspension member which do not require such deformation occupy significant amounts of space and require a relatively high clamping force to retain the suspension member. Such methods are prone to undertightening, resulting in slippage of the suspension member.
Thus, belts with such fiber tension members are typically terminated by capture of a substantially straight portion of the belt in a wedge-based termination. Such terminations utilize high clamping forces, which result in high shear stresses at the belt, in particular at an interface between the tension member and a enclosing the tension members. The high shear stresses may result in damage to the belt at the jacket/tension member interface.
In one embodiment, a termination device for a suspension member of an elevator system includes a housing and a wedge assembly located in the housing. The wedge assembly includes a wedge interactive with the housing to apply a clamping force to the suspension member in response to an axial load acting on the suspension member and a compliant shear element secured to the wedge or the suspension member and configured to reduce shear loads on the suspension member.
Additionally or alternatively, in this or other embodiments the compliant shear element is secured to a wedge inner surface and is configured to abut the suspension member.
Additionally or alternatively, in this or other embodiments the wedge assembly includes a wedge outer surface opposite the wedge inner surface, the wedge outer surface abutting a housing inner surface.
Additionally or alternatively, in this or other embodiments the compliant shear element is secured to one of the wedge or the suspension member via one or more of an adhesive, a mechanical fastener or a mechanically interlocking feature.
Additionally or alternatively, in this or other embodiments the compliant shear element has a stiffness in the range of 0.025 and 1.0 Giga Pascals.
Additionally or alternatively, in this or other embodiments the compliant shear element includes one or more friction-enhancing features to produce a desired frictional force between the compliant shear element and the suspension member.
In another embodiment, an elevator system includes a hoistway, an elevator car located in the hoistway, a suspension member operably connected to the elevator car to suspend and/or drive the elevator car along the hoistway, and a termination device located in the hoistway and operably connected to a suspension member end of the suspension member. The termination device includes a housing, and a wedge assembly located in the housing. The wedge assembly includes a wedge interactive with the housing to apply a clamping force to the suspension member in response to an axial load acting on the suspension member, and a compliant shear element secured to the wedge or the suspension member and configured to reduce shear loads on the suspension member.
Additionally or alternatively, in this or other embodiments the compliant shear element is secured to a wedge inner surface and abuts the suspension member.
Additionally or alternatively, in this or other embodiments the wedge assembly includes a wedge outer surface opposite the wedge inner surface, the wedge outer surface abutting a housing inner surface.
Additionally or alternatively, in this or other embodiments the compliant shear element is secured to the wedge via one or more of an adhesive, a mechanical fastener or a mechanically interlocking feature.
Additionally or alternatively, in this or other embodiments the compliant shear element has a stiffness in the range of 0.025 and 1.0 Giga Pascals.
Additionally or alternatively, in this or other embodiments the compliant shear element includes one or more friction-enhancing features to produce a desired frictional force between the compliant shear element and the suspension member.
Additionally or alternatively, in this or other embodiments the suspension member includes a plurality of tension elements extending along a length of the suspension member, each tension element including a plurality of fibers extending along the length of the suspension member bonded into a polymer matrix, and a jacket substantially retaining the plurality of tension members.
Additionally or alternatively, in this or other embodiments the plurality of fibers are formed from one or more of carbon, glass, polyester, nylon, or aramid material.
Additionally or alternatively, in this or other embodiments the compliant shear element is configured to reduce shear forces between the plurality of tension elements and the jacket.
The subject matter is particularly pointed out and distinctly claimed at the conclusion of the specification. The foregoing and other features, and advantages of the present disclosure are apparent from the following detailed description taken in conjunction with the accompanying drawings in which:
Shown in
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 24. The traction sheave 24 is driven by a machine 26. Movement of drive sheave by the machine 26 drives, moves and/or propels (through traction) the one or more belts 16 that are routed around the traction sheave 24. 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 26, but help guide the one or more belts 16 around the various components of the elevator system 10.
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 or only one side of the one or more belts 16 engages the one or more sheaves 18. The embodiment of
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.
Referring now to
Referring now to
A shear element 62 is located between the wedge inner surface 60 and the belt 16. The shear element 62 is configured to relax the shear loading on the belt 16, particularly at the interface between the tension elements 28 and the jacket 44, reducing shear levels at this interface to prevent damage to or failure of the interface. The shear element 62 is a compliant element, and is formed from, for example, a thermoplastic urethane (TPU), rubber or elastomeric material. In some embodiments, a stiffness of the shear element 62 is between about 0.025 and 1.0 Giga Pascals.
As shown in the graph of
Referring again to
Referring now to
The shear element 62 reduces shear forces at the jacket 44 and tension element 28 interface, thus reducing risk of damage and/or failure of the interface and reducing the risk of tension element 28 slippage at the termination 46.
While the present disclosure has been described in detail in connection with only a limited number of embodiments, it should be readily understood that the present disclosure is not limited to such disclosed embodiments. Rather, the present disclosure can be modified to incorporate any number of variations, alterations, substitutions or equivalent arrangements not heretofore described, but which are commensurate in spirit and/or scope. Additionally, while various embodiments have been described, it is to be understood that aspects of the present disclosure may include only some of the described embodiments. Accordingly, the present disclosure is not to be seen as limited by the foregoing description, but is only limited by the scope of the appended claims.
