Patent Application
20200002132
Exemplary embodiments pertain to the art of elevator systems. More particularly, the present disclosure relates to compensation members for high rise elevator systems utilizing lightweight suspension members.
Elevator systems utilize a suspension member operably connected to an elevator car and a counterweight in combination with, for example, a machine and traction sheave, to suspend and drive the elevator car along a hoistway. In high speed applications, typically greater than 3.5 m/s, compensation and tie-down members similarly extend between the elevator car and the counterweight, but via a tie-down sheave typically located in the bottom of the hoistway. The compensation member and tie-down sheave serve to stabilize operation of the elevator system.
High rise elevator systems utilizing lightweight suspension members require similarly lightweight members for compensation and tie-down. For high performance lightweight suspension members, approximately >3× strength/mass/length of wire rope, and high rises, approximately greater than 500 meters, wire rope of the same mass per unit length as the lightweight suspension member will not have sufficient strength for tie-down. On the other hand, utilizing the same lightweight member for both suspension and compensation and tie-down results in a compensation member having a strength exceeding what is required for tie-down by approximately a factor of 2, and which will increase cost of the elevator system.
In one embodiment, a compensation and tie-down member for an elevator system includes one or more lightweight compensation tension elements having a first tensile strength/unit mass/unit length, and one or more heavier weight compensation tension elements having a second tensile strength/unit mass/unit length less than the first tensile strength/unit mass/unit length.
Additionally or alternatively, in this or other embodiments the one or more lightweight compensation tension elements each comprise a plurality of fibers located in a matrix material.
Additionally or alternatively, in this or other embodiments the one or more heavier weight compensation tension elements each include a plurality of steel wires.
Additionally or alternatively, in this or other embodiments the compensation and tie-town member is configured as a compensation belt with the one or more lightweight compensation tension elements and the one or more heavier weight compensation tension elements are arrayed across a lateral width of the compensation and tie-down member.
Additionally or alternatively, in this or other embodiments a compensation jacket at least partially encapsulates the one or more lightweight compensation tension elements and the one or more heavier weight compensation tension elements.
Additionally or alternatively, in this or other embodiments the one or more heavier weight compensation tension elements are located at a laterally outermost position in the compensation and tie-down member.
Additionally or alternatively, in this or other embodiments the one or more lightweight compensation tension elements and the one or more heavier weight compensation tension elements are arranged as a rope.
Additionally or alternatively, in this or other embodiments the one or more heavier weight compensation tension elements is located at a center of the rope as a center strand, with the one or more lightweight compensation tension elements located as outer strands of the rope.
Additionally or alternatively, in this or other embodiments one or more lightweight compensation tension elements and one or more heavier weight compensation tension elements are arranged as outer strands of the rope.
In another embodiment, an elevator system includes a hoistway, an elevator car movable along the hoistway, one or more suspension members operably connected to the elevator car to move the elevator car along the hoistway, a counterweight operably connected to the elevator car via the one or more suspension members, and one or more compensation and tie-down members operably connected to the elevator car and the counterweight to stabilize operation of the elevator system. The one or more compensation and tie-down members includes one or more lightweight compensation tension elements having a first tensile strength/unit mass/unit length, and one or more heavier weight compensation tension elements having a second tensile strength/unit mass/unit length less than the first tensile strength/unit mass/unit length.
Additionally or alternatively, in this or other embodiments a total suspension member mass per unit length of the one or more suspension members is within +/−10% of a total compensation member mass per unit length of the one or more compensation and tie-down members.
Additionally or alternatively, in this or other embodiments the one or more suspension members each include a plurality of suspension tension elements, each suspension tension element including a plurality of fibers located in a matrix material.
Additionally or alternatively, in this or other embodiments a total number of compensation tension elements in the one or more compensation elements is fewer than the total number of suspension tension elements in the one or more suspension elements.
Additionally or alternatively, in this or other embodiments the number of compensation and tie-down members is fewer than the number of suspension members.
Additionally or alternatively, in this or other embodiments the one or more lightweight compensation tension elements each include a plurality of fibers located in a matrix material.
Additionally or alternatively, in this or other embodiments the one or more heavier weight compensation tension elements each include a plurality of steel wires.
Additionally or alternatively, in this or other embodiments the compensation and tie-down member is configured as a compensation belt with the one or more lightweight compensation tension elements and the one or more heavier weight compensation tension elements are arrayed across a lateral width of the compensation and tie-down member.
Additionally or alternatively, in this or other embodiments a compensation jacket at least partially encapsulates the one or more lightweight compensation tension elements and the one or more heavier weight compensation tension elements.
Additionally or alternatively, in this or other embodiments the one or more heavier weight compensation tension elements are located at a laterally outermost position in the compensation and tie-down member.
Additionally or alternatively, in this or other embodiments the one or more lightweight compensation tension elements and the one or more heavier weight compensation tension elements as arranged as a rope.
The following descriptions should not be considered limiting in any way. With reference to the accompanying drawings, like elements are numbered alike:
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
The elevator system 10 further includes one or more compensation and tie-down members 24 extending from the elevator car 14 toward a hoistway pit 26 around a tie-down sheave 28 and up to the counterweight 22. A tie-down mass 30 is disposed in the hoistway pit 26 and affixed to the tie-down sheave 28. The compensation and tie-down members 24, tie-down sheave 28 and tie-down mass 30 stabilize motion of the elevator car 14 along the hoistway 12.
Referring now to
The suspension members 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.
Referring now to
The belt 32 has a belt width 36 and a belt thickness 42, with an aspect ratio of belt width 36 to belt thickness 42 greater than one. The belt 32 further includes a back side 44 opposite the traction side 40 and belt edges 46 extending between the traction side 40 and the back side 44. While ten tension elements 34 are illustrated in the embodiment of
Referring now to
To balance the elevator system 10, the compensation and tie-down members 24 together have a compensation mass per unit length roughly equal to the sum of the suspension mass per unit length of the suspension members 16. In some embodiments, the compensation and tie down member mass per unit length is within +/−10% of the sum of the suspension mass per unit length of the suspension members 16. Further, a compensation tensile strength of the compensation and tie-down members 24 is about half of the suspension tensile strength of the suspension members 16. Because of the difference in strength requirement, it is desired to construct the compensation and tie-town members 24 differently from the suspension members 16 to take advantage of the lower tensile strength requirement while also matching the compensation mass per unit length to the suspension mass per unit length.
The suspension members 16 have a tensile load Factor of Safety (FOS) of 12 whereas the compensation and tie-down members 24 have a FOS of 5, resulting in nominally a 2:1 ratio. It should also be noted that lightweight suspension members 16 such as carbon fiber composite belts or synthetic fiber ropes can have (strength/weight/length) values significantly greater than steel wire rope or cords, being nominally 3 to 6 times greater.
Because the ratio of the suspension member FOS divided by the compensation member FOS is about 2:1, using the same tension member for both sides will result in excess strength on the compensation side. The present disclosure is an optimally tuned pair of suspension and compensation members which roughly balance the masses and have a nominally 2:1 ratio in strength. This optimally tuned configuration is associated with the full set of tension members 16, 24 bearing the loads for the elevator system. Thus, the sizing of the individual tension members 16, 24 is not of primary significance, but rather the different (strength/weight/length) ratios.
The current disclosure seeks to develop the optimally tuned compensation and tie down members 24 for elevator systems 10 which use lightweight suspension members 16 that have (strength/weight/length) ratios equal to or greater than 3 times that of convention elevator steel wire rope. For these systems 10, the (strength/weight/length) of steel wire rope is not high enough to have sufficient compensation member strength for nominally balanced tension member set mass. To achieve such an optimal compensation and tie-down member 24, a novel design is employed which uses two or more different compensation tension elements with substantially different (strength/weight/length) values. The different load bearing compensation tension elements are selected so that for two different elements, the ratio of their (strength/weight/length) is 2:1 or larger and for more than two different elements the ratio of the highest and lowest (strength/weight/length) values are 2:1 or larger. This includes the use of nominally non-load bearing material or ballast, such as steel in a non-rope or cord configuration. This configuration provides for balanced compensation to within 20% including the effects of the traveling cable and a strength ratio of nominally 2:1 which could range from 2.5:1 to 1.5:1. As before, this applies most broadly to the set of tension and compensation members, not the individual ones. However, it also can apply to each suspension member individually. As described in this configuration, the different tension elements are incorporated into a single member, thus mechanically coupling them which has the advantage of the tension element supporting the weight of the lower (strength/weight/length) element.
In a broader configuration, the compensation member set can be comprised of individual members with substantially different (strength/weight/length) ratios. An example of this would be to use lightweight suspension members and conventional wire rope side by side. The (strength/weight/length) ratios of the different suspension members would be 2:1 or greater.
Referring to
The compensation tension elements 62 are configured and arranged in the compensation belt 60 such that the compensation mass per unit length is substantially equal to the suspension mass per unit length. For example, the total compensation mass per unit length of the compensation and tie-down members 24 is within +/−10% of the total suspension mass per unit length of the suspension members 16. In other embodiments, the total compensation mass per unit length of the compensation and tie-down members 24 is within +/−5% of the total suspension mass per unit length of the suspension members 16. To achieve this, the compensation belt 60 may utilize a combination of lightweight compensation tension elements 62a and relatively heavier weight compensation tension elements 62b. Compensation tension elements 62a and 62b may differ in, for example, materials utilized to form the tension elements 62a and 62b. In some embodiments, the lightweight compensation tension elements 62a are formed from a plurality of fibers, such as carbon fiber, glass fiber aramid fiber, or their combination, disposed in a matrix material. Materials such as polyurethane, vinylester, or epoxy may be utilized as the matrix material. The lightweight compensation tension elements 62a have a first strength/mass/length. Heavier weight compensation tension elements 62b may be a steel cord, formed from a plurality of steel wires arranged into one or more strands 66. The heavier weight compensation tension elements 62b have a second strength/mass/length less than the first strength/mass/length. A heavier weight compensation tension element 62b formed from steel wires has a mass of about 3.5 times the mass of an equally-sized lightweight compensation tension element 62a formed from carbon fibers.
In the embodiment of
In the embodiment of
In other embodiments, such as shown in
In other embodiments, illustrated in
While described herein the context of compensation belts, one skilled in the art would readily appreciate that similar considerations may be applied to elevator systems 10 with other types of suspension members 16 and compensation members 24, such as elevator systems 10 utilizing synthetic fiber ropes.
The benefits of the compensation and tie-down member 24 configurations disclosed herein include reduction in cost of the compensation and tie-down members 24 while still meeting the tensile strength requirements.
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.
