WO2010059167A1

WO2010059167A1 - Tension arrangement for elevator system without a counterweight

Info

Publication number: WO2010059167A1
Application number: PCT/US2008/084493
Authority: WO
Inventors: Richard J. Ericson; Loren D. Fanion; Stephen R. Nichols; Robin Mihekun Miller; Harold Terry; Daryl J. Marvin
Original assignee: Otis Elevator Company
Priority date: 2008-11-24
Filing date: 2008-11-24
Publication date: 2010-05-27

Abstract

An exemplary tension device for maintaining a desired amount of tension on a traction and load bearing assembly that supports and moves an elevator car includes an anchor member configured to be secured in a fixed position in a hoistway. At least one sheave is rotatably supported on the anchor member. A lever has a first end pivotally supported for movement relative to the anchor member. A mass is at least partially supported by the lever near a second end of the lever. At least one termination is configured to secure an end of at least one portion of the traction and load bearing assembly relative to the lever. The termination is supported on the lever between the first end and the mass.

Description

TENSION ARRANGEMENT FOR ELEVATOR SYSTEM WITHOUT A COUNTERWEIGHT

BACKGROUND

[oooi] Elevator systems are useful for carrying passengers, cargo or both between various levels within a building, for example. Many elevator systems use a hydraulic arrangement for moving the elevator car as desired. Other elevator systems are traction-based and utilize a roping arrangement of load bearing members that support the elevator car. The load bearing members are also used for moving the elevator car. Traction between an elevator machine and the load bearing members allows the machine to move the load bearing members, which causes the desired movement of the elevator car.

[0002] Most traction-based elevator systems utilize a counterweight to maintain sufficient traction to achieve desired movement and position of the elevator car. While counterweight arrangements have proven effective, there are situations where it would be desirable to be able to eliminate a counterweight while still utilizing a traction-based elevator system. For example, some installations have limited space available and eliminating a counterweight would allow for reducing the size of the hoistway in new construction installations or would allow for maintaining the size of the car in modernization installations that replace hydraulic elevators.

[0003] Example elevator systems without a moving counterweight are shown in the published applications US 2006/0225965, WO 2004/094289 and WO 2004/094287. In those documents, a tensioning device acts directly on the load bearing assembly used for supporting and moving the elevator car.

[0004] Another situation presents challenges while attempting to use a counterweight. Replacing a hydraulic elevator drive arrangement with a traction- based arrangement can be problematic. Hydraulic elevator systems do not rely upon a counterweight. The hoistway is not arranged to accommodate a counterweight if it is designed for a hydraulic system, initially. When attempting to retrofit such a system with a traction-based arrangement, it is necessary to accommodate a counterweight within a hoistway space that previously was not configured to fit a counterweight. One approach at such a retrofitting arrangement is shown in GB 2,411,887. That document discloses a configuration for fitting a counterweight within a hoistway that previously included a hydraulic elevator system.

SUMMARY

[0005] An exemplary tension device for maintaining a desired amount of tension on a traction and load bearing assembly that supports and moves an elevator car includes an anchor member configured to be secured in a fixed position in a hoistway. At least one sheave is rotatably supported on the anchor member. A lever has a first end pivotally supported for movement relative to the anchor member. A mass is at least partially supported by the lever near a second end of the lever. At least one termination is configured to secure an end of at least one portion of the traction and load bearing assembly relative to the lever. The termination is supported on the lever between the first end and the mass. [0006] An exemplary elevator system includes an elevator car. A traction and load bearing assembly supports the elevator car. A machine selectively causes movement of the traction and load bearing assembly to cause movement of the elevator car. A first termination secures a first end of the traction and load bearing assembly above the elevator car. At least one upper sheave is positioned above the elevator car. A plurality of lower sheaves are positioned below the elevator car. At least one car sheave is supported on an underside of the elevator car. The car sheave moves with the elevator car. An anchor member is secured in a fixed position below the elevator car. The anchor member supports the lower sheaves. A lever has a first end pivotally supported by the anchor member. A mass is supported by the lever near a second end of the lever. A second termination is supported on the lever between the mass and the first end. The second termination secures a second end of the traction and load bearing assembly such that the mass provides tension on the traction and load bearing assembly sufficient to achieve traction for moving the traction and load bearing assembly and the elevator car. The traction and load bearing assembly at least partially wraps around the upper sheave, the lower sheaves and the at least one car sheave. The load supported by the traction and load bearing assembly is balanced relative to a center of the elevator car.

[0007] An exemplary method of changing an elevator system includes removing a hydraulic -based elevator machine arrangement from a hoistway and installing a traction-based elevator machine arrangement. A traction sheave, a plurality of deflector sheaves and a traction and load bearing assembly of the traction based elevator machine arrangement supports an elevator car and moves the elevator car. A mass is installed in a pit of the hoistway such that the mass remains in the pit during all operating conditions of the traction-based elevator machine arrangement. The mass provides tension on the traction and load bearing assembly sufficient to provide adequate traction between the traction sheave and the traction and load bearing assembly to achieve movement of the elevator car. The mass is supported on a lever that has a first end supported by an anchor member that supports at least one of the sheaves below the elevator car with the mass near a second end of the lever.

[0008] The various features and advantages of the disclosed examples will become apparent to those skilled in the art from the following detailed description. The drawings that accompany the detailed description can be briefly described as follows.

BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 schematically illustrates selected portions of an example elevator system.

[oooio] Figure 2 is an elevational view of one example tension device. [oooii] Figure 3 is a perspective illustration of the example of Figure 2.

[oooi2] Figure 4 schematically illustrates an example technique of changing an elevator system.

DETAILED DESCRIPTION [oooi3] Figure 1 schematically shows selected portions of an elevator system

20. An elevator car 22 is moveable between various levels within a hoistway 23. A machine (e.g., motor and brake) 24 causes the desired movement and placement of the elevator car 22. A traction and load bearing assembly (TLBA) 26 has one end secured by a termination 28 above the elevator car 22. The TLBA 26 wraps at least partially around deflection sheaves 32 and 34 that are supported for movement with the elevator car 22. In the illustrated example, the TLBA 26 is arranged in an underslung configuration because it passes beneath the elevator car 22 about the sheaves 32 and 34. The TLBA 26 then wraps at least partially around a traction sheave 36 that is located above the elevator car 22 in this example. Operating the machine 24 in a known manner using traction between the TLBA 26 and the traction sheave 36 achieves the desired movement and position of the elevator car 22.

[oooi4] The TLBA 26 extends from the traction sheave 36 down to a deflection sheave 38 located beneath the elevator car 22. The TLBA 26 also partially wraps around another deflection sheave 40 located beneath the elevator car 22. The TLBA 26 proceeds up and at least partially wraps around a deflection sheave 42 supported beneath the elevator car 22 for movement with the car. Another end of the TLBA 26 is secured by a termination 44.

[oooi5] Including the single deflection sheave 42 on the underside of the car 22 reduces the number of sheaves required compared to other arrangements. Moreover, the arrangement of the TLBA 26 as schematically shown in Figure 1 balances the loads relative to a center of the elevator car 22. Maintaining a balanced load in this regard better facilitates desired movement of the elevator car 22 within a hoistway 23 by reducing the likelihood that the car will tend to sway side-to-side. [oooiό] In the illustrated example, one edge or side of the deflection sheave 40 is spaced from the termination 44 a distance that is approximately equal to a diameter of the deflection sheave 42. This allows the portions of the TLBA 26 extending between the deflection sheave 40 and the termination 44 on the one hand to the deflection sheave 42 on the other hand to be parallel to each other and perpendicular to the floor of the elevator car 22. Additionally, using the single deflection sheave 42 for redirecting the TLBA 26 from the sheave 40 to the termination 44 reduces the weight and cost associated with the elevator car 22.

[oooi7] In this example, the termination 44 is secured to a lever 46. The example lever arrangement 46 allows for using existing pivoting joint terminations 44.

[00018] One end of the lever 46 is supported by an anchor member 48 that also supports at least the deflection sheave 40 in a desired position beneath the elevator car 22. A mass 50 is supported near an opposite end of the lever 46. The mass 50, the lever 46 and the location of the termination 44 on the lever 46 between the mass 50 and the end of the lever 46 that is supported by the anchor member 48 all cooperate to provide sufficient tension on the TLBA 26 to achieve a desired amount of traction for controlling movement of the elevator car 22.

[oooi9] The illustrated traction-based elevator system does not require a moving counterweight for purposes of maintaining the desired amount of tension on the TLBA 26. Although the mass 50 moves as the lever 46 pivots, the mass 50 remains in a pit of the hoistway 23 during all operating conditions of the elevator system 20. The mass 50 moves only minimally compared to the amount a traditional counterweight moves as the elevator car 22 moves. [00020] Another feature of the example of Figure 1 is a damper 51 associated with the mass 50 to damp movement of the mass 50 for purposes of reducing vibration that might otherwise be associated with movement of the mass 50. This provides enhanced elevator ride quality.

[00021] The example system does not require a separate roping arrangement for tension or balancing of loads. Additionally, it does not require separate drive cables and load supporting cables. The TLBA 26 supports all loads of the elevator car and provides the necessary traction as it is the only roping arrangement within the example elevator system 20 used for purposes of supporting the elevator car 22 or causing movement of it. [00022] In the example of Figure 1, the machine 24 is positioned above the elevator car 22. In another example, the machine 24 is located in the pit of the hoistway 23. In one example, the machine 24 is supported on the lever 46 so that it provides the entire mass 50 or at least a portion of the mass 50.

[00023] In the example of Figure 1, the TLBA 26 is shown as wrapping around two underslung sheaves 32, 34. In other embodiments, however, the sheaves 32, 34 could be placed on top of the car 22 in an overslung configuration.

[00024] Referring to Figures 2 and 3, an example tension device configuration including the anchor member 48, the lever 46 and the mass 50 includes a beam 52 that is secured to a hoistway pit surface 54 using fasteners 56. In one example, the fasteners 56 are at least partially provided within the pit floor during construction of the pit. In another example, the fasteners 56 are secured to the pit surface 54 in a retrofit installation. When the pit surface 54 comprises a concrete slab, appropriate concrete anchors may be selected by those skilled in the art.

[00025] The beam 52 is oriented parallel to the pit surface 54 and, in this example, parallel to the floor of the elevator car 22. The beam 52 in this example comprises two beam sections that are spaced apart from each other with the sheaves 38 and 40 extending between the two sections. The beam 52 provides rotatable support to the sheaves 38 and 40 such that they are rotatable relative to the anchor member 48. [00026] In the illustration of Figure 2, a hold down beam 60 is oriented at least partially transverse to the beam 52. The hold down beam 60 in this example is secured to a hoistway wall using a mounting bracket 62. The hold down beam 60 provides additional support for maintaining the beam 52 in the desired location relative to the pit surface 54.

[00027] The example of Figure 2 includes another anchor bracket 64 providing additional hold down support.

[00028] The lever 46 in this example comprises a first portion 70 that is oriented generally perpendicular to a second portion 72. In this example, the first portion 70 and the second portion 72 each comprise a plurality of beams that are spaced apart with a cross beam 76 extending between them.

[00029] A termination mounting member 78 extends between the two beams of the second portion 72 in this example. The termination mounting member 78, as best appreciated from Figure 3, supports the plurality of terminations 44 corresponding to the number of round ropes or flat belts used for the TLBA 26.

[00030] The mass 50 in this example includes a first portion 80 that is received within the spacing between the two beams of the first portion 72. Another portion 82 of the mass 50 is received above the beams of the first portion 72. A third portion 84 of the mass 50 in this example is received below the beams of the first portion 72. The entire mass 50 is supported by the lever 46 near one end of the second portion 72.

Positioning the mass 50 near the end of the lever 46 and the terminations 44 near a central location on the lever 46 provides a mechanical advantage of at least 2: 1. Such an arrangement reduces the amount of mass required for the mass 50. In one example, the mass 50 is approximately one -half the size of tensioning masses or counterweights from previous elevator arrangements.

[00031] One feature of the illustrated example is that the deflection sheave 40 rotates about the sheave axis 90. The lever 46 is pivotally supported on the anchor member 48 so that it pivots about a pivot axis that is coincident with the sheave axis 90. Having coincident axes provides for a more compact configuration that reduces the requirement for hoistway or pit space within which to fit the example tension device.

[00032] As can be appreciated from Figure 2, rail footings 92 are secured in a fixed position relative to the pit surface 54. Lower ends of guide rails 94 that are used for guiding movement of the elevator car 22 are secured to the rail footings 92. In this example, the rail footings 92 provide additional hold down support to the anchor member 48 by appropriate connections between the rail footings 92 and components of the anchor member 48.

[00033] One feature of the illustrated example is that only car guide rails 94 are required. No counterweight guide rails are needed. This provides cost savings in terms of materials and installation time.

[00034] Having the illustrated configuration including a common axis about which the sheave 40 rotates and the lever 46 pivots provides a single anchor point for the entire tension device, which simplifies installation and better-utilizes hoistway and pit space. Minimizing the footprint in the pit reduces the amount of hoistway size required by the tension device. This allows for utilizing a larger elevator car 22, for example. Additionally, all of the space typically allocated for a moving counterweight is usable for other purposes such as additional building space outside of the hoistway or increased elevator car size. [00035] Another feature of the example arrangement is that it is well-suited for retrofitting a hydraulic-based elevator system with a traction-based elevator system. One challenge at retrofitting hydraulic systems in the past has been determining an economical way to incorporate a moving counterweight into a hoistway that was not originally designed to accommodate one. With the illustrated example, there is no requirement for a moving counterweight and it is much easier to retrofit a hydraulic- based elevator system with a traction-based arrangement.

[00036] Figure 4 schematically illustrates a process of removing a hydraulic- based elevator machine arrangement 100 from a hoistway. A traction based elevator machine arrangement such as that shown in Figures 2 and 3 is installed in the hoistway. By installing the mass 50 in the pit of the hoistway, there is no requirement for accommodating a moving counterweight within the space previously allocated to the hydraulic arrangement 100.

[00037] There are various features of the illustrated examples. The levered arrangement is well suited to limited space availability in a hoistway pit. The reduced mass, size and cost of the example tension device makes it more economical to retrofit an existing building or hoistway compared to other traction-based arrangements. The reduced size of the mass 50 allows for the mass 50 to be made of a wider variety of material such as pre-cast concrete, steel or cast iron. [00038] The compact arrangement of the components allows for easier shipping, handling and installation. This increases the economies associated with installation or retrofitting an elevator system. For example, the pit tensioning arrangement of the illustrated example can be completely factory pre- assembled, and dropped into position using a fork lift truck or other commercial rigging device, without modification to an existing or new pit size or shape.

[00039] Minimizing hoistway size is possible because the space normally occupied by the counterweight is no longer required. This feej44&β£*÷facilitates maximization of rentable floor space for high rise elevator applications, without increasing the size or depth of pit space required.

[00040] The levered system as described above is a material improvement over the prior art because a levered tensioning system is significantly reduced in size and mass, and can fit in an existing available hoistway pit. The levered system also provides a feature useful for damping vibrations and noise, thus improving car ride and passenger comfort. The ability of the mass to move up and down as the lever pivots reduces tension variations in the TLBA that otherwise tend to occur upon elevator car acceleration and deceleration. A shock absorber element can also be added to the device to damp the motion of the pivoting tension mass, which further improves car ride in some examples. [00041] The preceding description is exemplary rather than limiting in nature.

Variations and modifications to the disclosed examples may become apparent to those skilled in the art that do not necessarily depart from the essence of this invention. The scope of legal protection given to this invention can only be determined by studying the following claims.

Claims

CLAIMSWe claim:

1. A tension device for maintaining a desired amount of tension on a traction and load bearing assembly for supporting and moving an elevator car, comprising: an anchor member configured to be secured in a fixed position in a hoistway; at least one sheave rotatably supported on the anchor member; a lever having a first end pivotally supported for movement relative to the anchor member; a mass at least partially supported by the lever near a second end of the lever; and at least one termination configured to secure an end of at least one portion of the traction and load bearing assembly, the at least one termination being supported on the lever between the first end and the mass.

2. The device of claim 1, wherein the at least one sheave is rotatable about a sheave axis and the lever is pivotable about a pivot axis and wherein the sheave axis and the pivot axis are coincident.

3. The device of claim 1, wherein the anchor member comprises an anchor beam that is configured to be secured in a position generally parallel to a pit floor of a hoistway and the at least one sheave is supported by the beam.

4. The device of claim 3, wherein the lever comprises a first portion that is coupled with the anchor beam and a second portion oriented generally perpendicular to the first portion and generally parallel to the anchor beam.

5. The device of claim 1, wherein the lever comprises a plurality of spaced apart members and the mass is at least partially received in a spacing between the spaced apart members and another part of the mass is outside of the spacing.

6. The device of claim 3, comprising a hold down beam that is generally transverse to the anchor beam, the hold down beam being configured to be secured to a surface in a hoistway to maintain the anchor beam in a desired position.

7. The device of claim 1, comprising at least one rail footing configured to at least partially support a guide rail, the at least one rail footing being coupled with the anchor member.

8. The device of claim 1, wherein the anchor member provides a single structure for mounting the at least one sheave, the lever and the mass in a pit of a hoistway.

9. An elevator system, comprising: an elevator car; a traction and load bearing assembly that supports the elevator car; a machine that selectively causes movement of the traction and load bearing assembly to cause movement of the elevator car; a first termination securing a first end of the traction and load bearing assembly above the elevator car; at least one upper sheave above the elevator car; a plurality of lower sheaves below the elevator car; at least one car sheave supported on an underside of the elevator car for movement with the elevator car; an anchor member secured in a fixed position below the elevator car, the anchor member supporting the lower sheaves; a lever having a first end pivotally supported by the anchor member; a mass supported by the lever near a second end of the lever; and a second termination supported on the lever between the mass and the first end, the second termination securing a second end of the traction and load bearing assembly such that the mass provides tension on the traction and load bearing assembly sufficient to achieve traction for moving the traction and load bearing assembly and the elevator car, wherein the traction and load bearing assembly at least partially wraps around the upper sheave, the lower sheaves and the at least one car sheave such that the load supported by the traction and load bearing assembly is balanced relative to a center of the elevator car.

10. The system of claim 9, wherein the car sheave has a diameter and a distance between one of the lower sheaves and the termination is approximately equal to the diameter.

11. The system of claim 9, wherein at least one of the lower sheaves is rotatable about a sheave axis, the lever is pivotable about a pivot axis and the sheave axis and the pivot axis are coincident.

12. The system of claim 9, wherein the anchor member comprises a beam that is secured in a position generally parallel to a floor of the elevator car and the lower sheaves are supported by the beam.

13. The system of claim 12, wherein the lever comprises a first portion that is coupled with the beam and a second portion oriented generally perpendicular to the first portion and generally parallel to the beam.

14. The system of claim 9, wherein the lever comprises a plurality of spaced apart members and the mass is at least partially received in a spacing between the spaced apart members and another part of the mass is outside of the spacing.

15. The device of claim 12, comprising a hold down beam that is generally transverse to the anchor beam, the hold down beam being secured in a position to maintain the hold down beam in a desired position.

16. The system of claim 9, comprising a plurality of guide rails that guide vertical movement of the elevator car; and at least one rail footing coupled with the anchor member, the rail footing at least partially supporting a portion of at least one of the guide rails.

17. The system of claim 9, wherein the anchor member provides a single structure for mounting the lower sheaves, the lever and the mass below the elevator car.

18. A method of changing an elevator system, comprising the steps of: removing a hydraulic-based elevator machine arrangement from a hoistway; installing a traction-based elevator machine arrangement in the hoistway including a traction sheave, a plurality of deflector sheaves and a traction and load bearing assembly that supports an elevator car and moves the elevator car; and installing a mass in a pit of the hoistway such that the mass remains in the pit during all operating conditions of the traction-based elevator machine arrangement and provides tension on the traction and load bearing assembly sufficient to provide adequate traction between the traction sheave and the traction and load bearing assembly to achieve movement of the elevator car, wherein the mass is supported on a lever that has a first end supported by an anchor member that supports at least one of the sheaves below the elevator car with the mass near a second end of the lever.

19. The method of claim 18, wherein the lever pivots about a pivot axis, the at least one of the sheaves rotates about a sheave axis and the pivot axis is coincident with the sheave axis.