EP1123891A2

EP1123891A2 - Dead end hitch for elevator rope

Info

Publication number: EP1123891A2
Application number: EP01301162A
Authority: EP
Inventors: Boris Traktovenko
Original assignee: Otis Elevator Co
Current assignee: Otis Elevator Co
Priority date: 2000-02-09
Filing date: 2001-02-09
Publication date: 2001-08-16
Also published as: EP1123891A3; JP2001247277A

Abstract

A dead end hitch (80) is disclosed for traction elevator systems that minimizes the height requirements within an elevator hoistway. The dead end hitch (80) includes a substantially non-vertical lever (90) pivotally attached to a support structure (50). A termination device (66) for terminating a tension member (68) is supported by the lever (90) at a height position substantially the same as the height position of the lever (90). Tension equalization devices such as springs (96) may be disposed at various locations of the lever (90). In one embodiment, the tension equalisation device is located intermediate the lever end (82) and the termination device (66). In another embodiment (Fig. 4) the tension equalization device (76) is located at a lever end (62) remote from the termination device (66). The configuration disclosed reduces the amount of vertical space needed within the elevator hoistway for the dead end hitch (80).

Description

The present invention relates generally to traction elevator systems and more particularly to dead end hitches for traction elevator systems.
Traction elevator systems having 2:1 roping configurations typically include a car and counterweight connected through idler pulleys to multiple tension members with the tension members extending over a traction sheave effectively between the idler pulleys with respect to the rope. The traction sheave is rotationally driven by a machine mounted in a machine room above the hoistway to displace the car and the counterweight in an opposing motion relationship. It is necessary to terminate the ends of the rope to an overhead support structure. This is generally accomplished though the use of termination devices and dead end hitches (to which the termination devices mount). The dead end hitches are in turn supported by the support structure such as the ceiling of the hoistway or a separate support member. While conventional units are safe and reliable, significant overhead clearance is required to mount such conventional dead end hitches. Because building space is at a premium, a device that generally increases the total height required in an elevator hoistway is not desirable. It is desirable to reduce the space required above the top of the elevator car when the car is at its highest location.
For the foregoing reasons, a need exists to minimize the height requirements of dead end hitches.
A dead end elevator hitch assembly is provided herein that reduces the overhead clearance requirements of conventional dead end hitch arrangements. Conventional dead end hitch assemblies generally include a vertical member suspended from a support structure. The termination device is situated beneath the dead end hitch for suspending a load such as an elevator car or counterweight by tension members. However, while safe and reliable, conventional dead end hitch configurations require additional height in the elevator hoistway.
In accordance with the invention there is provided a dead end hitch in an elevator system comprising:
a lever arranged non-vertically, said lever being attached to a structure in the elevator system by a pivot, and supporting a termination device; and
a tension equalizing device disposed between said lever and the structure.
The dead end hitches embodying the invention described herein substantially reduce the height required in the elevator hoistway by allowing the termination device to be supported at substantially the same height as the dead end hitch. The dead end hitch includes a lever positioned non-vertically, and preferally generally horizontally, and pivotally supported by the support structure. The location and type of pivotal support may be adapted to the particular support configurations.
Another feature of the present invention is the versatility it affords in the positioning of tension equalization springs and any height adjustment mechanisms. In conventional arrangements, tension equalization springs (or other tension member equalization or vibration isolation assemblies) add to the overall required height of the hoistway. However, with the arrangements described herein, the tension equalization spring and any height adjustment mechanisms may be positioned on approximately the same vertical level as the termination device, rather than above the termination device.
Further features and advantages of the present invention will become readily apparent to those skilled in this art from the following detailed description and accompanying drawings, wherein only preferred embodiments of the invention are shown and described, simply by way of illustration. The drawings and description are to be regarded as illustrative in nature, and not as restrictive on the scope of the invention.
Referring now to the drawings wherein like elements are numbered alike in the several FIGURES:
Figure 1 is a schematic of a traction elevator system utilizing a 2:1 roping configuration;
Figure 2 is a schematic of an existing dead end hitch;
Figure 3 is a schematic of a swivel version of an existing dead end hitch;
Figure 4 is a schematic of an embodiment of a dead end hitch of the present invention;
Figure 5 is a schematic of another embodiment of a dead end hitch of the present invention;
Figure 6 is a front perspective view of a portion of a dead end hitch;
Figure 7 is a side elevation of the embodiment of the dead end hitch as depicted in Figure 6;
Figure 8 is a schematic diagram representing the range of vertical adjustment of the present invention;
Figure 9 is a top plan view of dead end hitches supporting multiple tension members (not shown); and
Figure 10 is a cross-sectional view of the dead end hitches as depicted in Figure 9 at section A-A.
Referring now to the drawings, and particularly to Figure 1, a schematic view of a well known traction elevator system 10 utilizing a 2:1 roping configuration is generally depicted. Traction elevator system 10 generally includes a car 12 and a counterweight 14 which are mounted in an elevator shaft of a building for vertical movement between pre-determined travel limits. A sheave and tension member arrangement for driving car 12 and its counterweight 14 includes a tension member 16 attached at one end to a first dead end hitch 30 extending to the undersides of idler sheaves 18 positioned atop car 12. Tension member 16 extends to a traction sheave 20 generally situated proximate to the top of the hoistway, and further traverses a second idler sheave 22 atop counterweight 14 and extends therefrom to a second dead end hitch 32. Traction sheave 20 is powered by a traction drive machine 24, which may include an AC or DC drive motor, to drive traction sheave 20 causing car 12 and counterweight 14 to become vertically displaced in an opposing motion relationship. It is, of course, contemplated that the configuration of the traction drive components can vary. For example, idler sheaves 18 may be positioned beneath car 12 and idler sheave 22 may be positioned beneath counterweight 14.
Both first and second dead end hitches 30 and 32 attach to an overhead support structure 26, which may comprise, for example, a beam or slab resting upon or extending from vertical supports (not shown). The instant invention is concerned generally with minimizing the distance that either or both dead end hitches extend below support structure 26.
Figure 2 schematically depicts an existing dead end hitch 40 having a shackle 42 generally disposed through a support structure 26 to maintain the weight of car 12 or counterweight 14 (not shown) suspended by a tension member 48 via an intermediary termination device 46. Support structure 26 may depend from a vertical support or wall 27, or can be, for example, a horizontally configured member traversing a structure. A force arrow F represents the overall force applied to support 26. The moment applied to support 26 can be determined generally from F and the distance L, which represents the distance between vertical support 27 and tension member 48. Above the support structure 26, a tension equalization spring 44 provides bias between shackle 42 and support structure 26. Tension equalization spring 44 is maintained in position by resting atop support structure 26 and is maintained between support structure 26 and the top of shackle 42 by, for example, a blocking portion or collar 43 (in one arrangement) perpendicularly from shackle 42. The overall height of dead hitch 40 is determined by the length of shackle 42, which is generally defined by the height of tension equalization spring 44, the spring stroke and the thickness of support structure 26.
Referring now to Figure 3, a schematic of a conventional swivel dead end hitch 40 generally known in the art is shown. The swivel feature reduces the bending moment on the termination and the tension member upon occurrence of horizontal pull on tension member 48. Such a dead end hitch includes shackle 42 pivotally attached at a pivot 38 intermediate to support 26 and vertical support structure 27. Dead end hitch 40 includes a load (not shown) attached by tension member 48 via termination device 46. Above pivot 38 tension equalization spring 44 is disposed and maintained thereon by a blocking portion or collar 43 protruding perpendicularly (in one arrangement) from shackle 42. Pivot 38 allows the hitch assembly 40 to rotate thereby reducing the bending moment on termination device 46 and tension member 48 when horizontal forces are exerted upon tension member 48 and/or termination device 46.
Turning now to various embodiments of the present invention, dead end hitches are provided that substantially reduce the height required at the top of an elevator hoistway. This is accomplished by generally by supporting the termination device at substantially the same height as a dead end hitch. The dead end hitch, including a lever configured generally non-vertically and a tension equalization device between the non-vertical lever and a structure of the elevator hoistway, is positioned at approximately the same vertical height as the end of the termination device opposite the end terminating the tension member (i.e., the supported end).
Figure 4 is a schematic view of a dead end hitch 60 embodying the present invention. The top of an elevator hoistway is generally shown including a lateral support 50 and a vertical member 52. Lateral support 50 is, for example, a ceiling or separate support or structural member capable of holding the weight of dead end hitch 60 and the load (elevator car or counterweight) attached thereto. Lateral support 50 also is integral with, or depends from, vertical member 52 which is, for example, a hoistway wall or side rails.
Dead end hitch 60 includes a lever 70 attached to lateral support 50 by hangers 74 at a pivot 72. Pivot 72 is intermediate to a first lever end 61 and a second lever end 62. First lever end 61 is generally proximate to vertical member 52. The materials of construction may vary for dead end hitch 60 (and further dead end hitches detailed herein). In one arrangement, lever 70 is formed of bar steel cut to the desired size. Furthermore, it is contemplated that the positioning of pivot 72 can differ. That is, while the embodiment shown in Figure 4 includes pivot 72 located generally centrally upon lever 70, one skilled in the art will appreciate that the precise location of pivot 72 may vary depending on factors including, but not limited to, the positioning of the other components, their weights and other balancing considerations.
A termination device 66 having tension member 68 extending therefrom supports a load such as a car or counterweight (not shown). The termination device 66 includes a clevis, or a short shackle having a clevis, at its supported end that is pivotally attached to lever 70 at first lever end 61. In this configuration, termination device 66 may be supported by the pivotal attachment at substantially the same height as lever 70, rather than below a shackle as shown with reference to Figures 2 and 3.
A tension equalization device such as a spring 76 is disposed between lever 70 (generally at second end 62) and lateral support 50. Spring 76 compensates for variations on the tension in tension member 68 (particularly when a plurality of tension members 68 are employed) and to provide vibrational isolation from the vibrations of tension member 68.
Referring now to Figure 5, a schematic of another configuration of a dead end hitch 80 embodying the present invention is provided. Dead end hitch 80 includes a lever 90 having a first lever end 81 and a second lever end 82. Lever 90 is pivotally attached to support 50 at a pivot 92. Pivot 92 is situated on lever 90 at second lever end 82. Hangers 94 secure pivot 92 to lateral support 50.
Termination device 66 is attached to a first lever end 81 of a lever 90 proximate to vertical member 52 generally as described above, thereby supporting termination device 66 at substantially the same height as lever 90.
A tension equalization device is positioned between lateral support 50 and lever 90. The tension equalization device includes a spring 96 positioned on an intermediate member 98. Member 98 is generally shaped as a rod and is connected to lateral support 50. Spring 96 is positioned below lever 90 generally intermediate to first lever end 91 and second lever end 82. Spring 96 is maintained on member 98 by a blocking portion or collar 97. Member 98 and collar 97 may be, for example, a monolithic structure. Alternatively, collar 97 may be removable from member 98 (i.e., collar 97 may be a threaded nut). Member 98 may be, for example, a rod positioned through an opening in lever 90. Alternatively, member 98 can be configured to fit around lever 90. It will be appreciated by one skilled in the art that the configuration of the tension equalization device may readily be changed.
Force arrows F (shown in Figures 4 and 5) represent the overall force applied to support 50. Additionally, the moment applied to support 50 is determined generally from F and the distances L between tension member 68 and vertical support 52. The force and moment applied to the support are generally the same as for a conventional design (for example, as shown in Figure 2), while also eliminating the need for a shackle that is subject to horizontal stresses.
The distance required for the dead end hitch can be further reduced by placing one or more levers (similar to lever 70 described with respect to Figure 4 and lever 90 described with respect to Figure 5) between a plurality of generally parallel support members. Referring now to Figures 6, 7, 9 and 10, a dead end hitch assembly 100 is depicted. The structural configuration of the hoistway generally includes vertical member 52 having a plurality of lateral supports 50 depending substantially perpendicularly therefrom. Further, a cross-member 54 is located atop lateral supports 50.
Dead end hitch 100 includes a lever 110 generally supported by lateral supports 50. Lever 110 is pivotally maintained between lateral supports 50 by a pin 115 disposed through pivot apertures 114 upon lateral supports 50 and lever 110. Termination device 66 having tension member 68 extending therefrom is pivotally supported by lever 110 at first lever end 111. Lever 110 is formed generally of a pair of cut bar steel members bent and secured together (for example, welded together) so that there is an opening or gap between the first lever end 111 and a second lever end 112 to allow a tension equalization device to be positioned between lever 110 and cross-member 54. The tension equalization device includes a rod 118 generally supporting a spring 116. Of course, it is contemplated that the opening may be accomplished by casting lever 110 or by machining an opening.
Rod 118 is secured to cross-member 54 by a securement means such as a nut 122. Spring 116 is disposed upon rod 118 below lever 110 and is maintained thereon by, for example, a protrusion or a collar 120.
The height of termination device 66 may also be adjusted by increasing or decreasing the extension length (i.e., the length of rod 118 that extends below lever 110 and that maintains spring 116). For example, by increasing the extension length, termination device 66 is at a lower position as lever 110 is sloped downwardly due to the rotation about pin 115 (see Figure 7, lever 110b in phantom). Conversely, by decreasing the extension length, termination device 66 is at a higher position as lever 110 is sloped upwardly due to the rotation about pin 115 (see Figure 7, lever 110a in phantom). The depicted configuration having rod 118 secured to cross-member 54 is ideal for adjustability, as nut 122 may be rotated to increase or decrease the extension length. Alternatively, a nut or other adjustable device may be positioned under lever 110 upon rod 118, i.e., adjacent to spring 116, to vary the length of rod 118. However, it is contemplated that where adjustability is not required, other configurations may be employed. For example, rod 118 may be welded to cross-member 54, or rod 118 and cross-member 54 may be a monolithic member.
The present design provides a large degree of adjustability relative to the overhead height required since much of the vertical space used for lever rotation, which is between lateral supports 50, is otherwise unusable. Furthermore, the horizontal motion upon vertical adjustment if minimal. Referring now to Figure 8, a diagram representing the range of vertical adjustment is provided. For a lever arm having a length of 200 mm, a degree of vertical adjustment equal to 50 mm requires 14 degrees of rotation up and down from the position of lever 110 parallel to lateral support 50. In providing 50 mm of vertical adjustment in the schematic shown, only 1.5 mm of lateral motion results. Consequently, in addition to minimizing vertical space required, the design of Figures 6-10 minimizes required lateral space in the hoistway.
While four lateral supports 50 and three levers 110 are shown in Figures 9 and 10, it is understood that more or less lateral supports 50 may be included thereby changing number of the locations available for levers 110. It is also understood that neighboring lateral supports 50 may or may not have a lever 110 supported therebetween. The positioning of levers 110 is generally complementary to the arrangement of tension member or tension members.
To facilitate assembly and minimize the total number of components, a common pin 115 can be used, as shown in Figure 9. That is, a pin 115 may be disposed through a plurality of pivot apertures 114 upon lateral supports 50 and levers 110.
To perform maintenance or adjustments to one of the dead end hitch assemblies 100, the remaining dead end hitch assemblies may be structurally supported by one or more pins 126 disposed through secondary apertures 124 upon lateral supports 50 and lever 110. Thereafter, pin 115 may be removed from apertures 114.
While preferred embodiments have been shown and described, various modifications and substitutions may be made thereto without departing from the scope of the invention. Accordingly, it is to be understood that the present invention has been described by way of illustration and not limitation.

Claims

A dead end hitch (60; 80; 100) in an elevator system (10) comprising:

a lever (70; 90; 110) arranged non-vertically, said lever (70; 90; 110) being attached to a structure (50) in the elevator system by a pivot (72; 92; 115), and supporting a termination device (66); and

a tension equalizing device disposed between said lever (70; 90; 110) and the structure (50).
A dead end hitch as in claim 1, wherein said pivot (72) is positioned intermediate a first position (61) and a second position (62), said first position (61) being a position on said lever (70) where said tension equalization device is disposed, and said second position (62) being a position on said lever (70) where the termination device (66) is supported.
A dead end hitch as in claim 1 or 2, wherein said tension equalization device includes a spring (76), said spring (76) being disposed between the lever (70) and the structure (50).
A dead end hitch as in claim 1, wherein said tension equalization device is positioned intermediate a first position (81; 91; 111) and a second position (82; 112), said first position (81; 91; 111) being a position on said lever (90; 110) where said pivot (92; 115) is disposed, and said second position (82; 112) being a second position on said lever (90; 110) where the termination device (66) is supported.
A dead end hitch as in claim 4, wherein said tension equalization device includes a member (98; 118) and a spring (96; 116), said member (98; 118) being attached to the structure (50), and said spring (96; 116) being disposed between said member (98; 118) and said lever (90; 110).
A dead end hitch as in claim 5, wherein said lever (90; 110) includes an opening, said member (98; 118) being disposed through said opening.
A dead end hitch as in claim 5 or 6, wherein said member (98; 118) is configured to adjust the position of the lever (90; 110).
A dead end hitch as in claim 5, 6 or 7, wherein said member (98; 118) is configured by including a threaded portion on said member adapted to receive a nut (122).
A dead end hitch as in any of claims 5 to 8, wherein the structure (50) includes a pair of lateral members (50) having a vertical height, wherein the lever (110) is attached between the lateral members (50) at a vertical position that at least partially overlaps the vertical height of the lateral members (50).
A dead end hitch as in claim 9, wherein the structure (50) further includes a cross member (54) disposed over the lateral members (50), wherein the member (118) of the tension equalization device is attached to the cross member (54).