US3810529A

US3810529A - Elevator system

Info

Publication number: US3810529A
Application number: US00364162A
Authority: US
Inventors: L Tosato; F Solymos
Original assignee: Westinghouse Electric Corp
Current assignee: CBS Corp
Priority date: 1973-05-25
Filing date: 1973-05-25
Publication date: 1974-05-14
Anticipated expiration: 1991-05-14
Also published as: JPS5346333B2; ES426626A1; FR2230575A1; DE2425216A1; BR7404162D0; BE815461A; FR2230575B1; JPS5020449A; GB1465166A; AU6899774A; CA974900A; IT1013905B

Abstract

An elevator system including an elevator car and counterweight interconnected via hoisting roping for movement in the hoistway of a building having a plurality of landings to be served by the elevator car. Compensation for the hoisting roping includes a chain which interconnects the car and counterweight, and a compensator sheave which guides and tensions the chain. The sheave includes a circumferential groove formed by first and second axially spaced elastomeric members, with the grooves being sized such that alternate links of the chain extend edgewise into the groove, while the intervening links rest against the outer peripheries of the first and second members.

Description

United States Patent [191 Tosato et al.

[111 3,810,529 1451 May 14, 1974 ELEVATOR. SYSTEM [75] Inventors: Lawrence Tosato, Millburn;

Frederick Solymos, Glen Ridge, both of NJ.

[73] Assignee: Westinghouse Electric Corporation,

Pittsburgh, Pa.

[22] Filed: May 25, 1973 [2i] Appl. No.: 364,162

[52] US. Cl. 187/94, 254/190 R [51] Int. Cl B66!) l7/l2, 866d H36 [58] Field of Search 187/94; 254/190 R [56] References Cited UNITED STATES PATENTS 3,279,762 l0/l966 Bruns l87/94 X Primary Examiner-Richard E. Aegerter Assistant ExaminerH. S. Lane Attorney, Agent, or Firm--D. R. Lackey 5 7] ABSTRACT An elevator system including an elevator car and counterweight interconnected via hoisting roping for movement in the hoistway of a building having a plurality of landings to be served by the elevator car. Compensation for the hoisting roping includes a chain which interconnects the car and counterweight, and a compensator sheave which guides and tensions the chain. The sheave includes a circumferential groove formed by first and second axially spaced elastomeric members, with the grooves being sized such that alternate links of the chain extend edgewise into the groove, while the intervening links rest against the outer peripheries of the first and second members.

9 Claims, 9 Drawing Figures PATENTEBm 14 1914 same or 3 FIG ELEVATOR SYSTEM BACKGROUND OFTHE INVENTION 1. Field of the Invention The invention relates in general to elevator systems, and more specifically to elevator systems which utilize chain compensation for the hoisting roping.

2. Description of the Prior Art When the total travel distance of an elevator car in a building can exceed about 100 feet, the weight of the hoisting ropes which interconnects the car'and counterweight via the traction sheave, adds significantly to the unbalanced load which must be lifted and accelerated by the elevator drive machine, with the amount of unbalance continuously changing as the elevator car and counterweight move in the hatchway. Thus, it is conventional to provide some type of compensation 7 system to reduce the unbalanced load for any position of the car and counterweight in the hoistway. The compensation system makes torque requirements more uniform and assists in landing accuracy.

Conventional or ordinary link chains are used for the compensating weight on elevator systems which operate below about 400 feet per minute. Chain compensation is attractive because of its low cost, but chains become excessively noisy above speeds of 400 feet per minute. Thus, a plurality of wire ropes reeved about a weighted compensator sheave are conventionally used on elevator systems which exceed a speed of about 400 feet per minute.

Since chain compensation has distinct economic advantages over rope compensation, ways are constantly being sought to reduce chain noise and chain sway, to thus enable chain compensation to be successfully used at higher elevator speeds. Co-pending application Ser.

No. 240,241, filed Mar. 31, 1972, now US. Pat. No. 3,768,596 which is assigned to the same assignee as the present application, teaches an arrangement for reducing chain noise, which arrangement extends the upper speed limit for chain compensated elevator systems to about 500 feet per minute. With this arrangement, resilient spacers formed of a material such as rubber, are disposed about alternate links of the chain. The spacers are dimensioned to fully extend the links and to maintain them in their extended position, which reduces the noise in the natural loop of the chain formed below the car and counterweight, and it also reduces the noise due to the chain striking components in the hoistway due to chain sway, by using spacers which have an out side diameter larger than the width dimension of the links.

US. Pat. No. 2,537,075 teaches the use ofa substantially U-shaped rubber tire on a sheave for reducing chain noise.

Resilient spacers, while successfully increasing the top speed limit of a chain compensated elevatorsystem to about 500 feet per minute, reduce the economic advantage of chains over wire ropes, since the resilient spacers are disposed over alternate links of the chain over substantially the complete length of the chain. Further, while the noise created by the chain striking the sides of the hoistway is reduced, it would be desirable to completely eliminate chain sway, if it can be accomplished economically and without creating maintenance problems.

Reeving the chain about a sheave which is faced with sound deadening material prevents sway of the chain and reduces chain noise in the loop, but at the expense of increasing maintenance costs. The chain links dig into the firmly backed sound deadening material, resulting in accelerated wear thereof.

SUMMARY OF THE INVENTION Briefly, the present invention is a new and improved elevator system which includes an elevator car and counterweight interconnected via hoist roping. and via compensation for the weight of the hoist roping. The compensation includes a link chain and a sheave. The link chain is connected to the bottoms of the car and counterweight, extending downwardly therefrom about the sheave, which is disposed in the pit.

The sheave includes elastomeric means disposed about its periphery. The elastomeric means may be a single structure having first and second axially spaced members which extend outwardly from a common back portion to define a circumferential groove; or, it may include first and second independent members which are held in spaced relation to provide a circumferential groove. In a preferred embodiment of the invention, the first and second members are substantially cylindrical and tubular in cross-sectional configuration.

The first and second members are sized and axially spaced such that alternate links of the chain extend edgewise into the circumferential groove while the intervening links remain outside the groove, the flat broad sides of which are supported by the outer peripheries of the first and second members. The depth of the groove is selected such that it exceeds the dimension of the portion of the link which extends into the groove, precluding any digging of the link into the elastomeric material or the backing support therefor. The sides of the members which define the groove support and contact opposite sides of the links which extend therein, providing a positive guide for the chain. Compression of the first and second members by the flatwise sides of the chain links compresses the cylindrical members into an elliptical configuration which reduces the width of the circumferential groove to provide a firm guide for different chain sizes without the necessity of changing the unstressed width of the circumferential grooves.

BRIEF DESCRIPTION OF THE DRAWINGS l a sheave constructed according to the teachings of the invention, which may be used for the compensator sheave shown in FIG. 1;

FIG. 3 is a fragmentary view of one edge of the sheave shown in FIG. 2;

FIGS. 4,5, 6, 7 and 8 are cross-sectional views of a portion of the sheave shown in FIG. 2, taken between the arrows IV-IV, illustrating different structural arrangements which may be used for providing a circumferential groove in the sheave; and

FIG. 9 is a perspective view of an elevator system which may be constructed according to the teachings of the invention. I

DESCRIPTION OF PREFERRED EMBODIMENTS Referring now to the drawings, and FIG. 1 in particular, there is shown a traction elevator system 10 constructed according to the teachings of the invention. Elevator system 10 includes an elevator car 12 mounted for movement in a hoistway 14 of a structure or building having a plurality of floors, indicated generally at 16, which floors are served bythe elevator car 12. An elevator drive motor 18 may be mounted on the floor of a penthouse in the building, which floor is illustrated generally by line 20, with the drive motor having a drive shaft 22 to which a traction sheave 24 is secured. An idler or deflection sheave 26 may be secured to the lower surface of the penthouse floor 20, if required.

Hoist ropes or cables 28 interconnect the elevator car 12 with a counterweight 30. The hoist ropes 28, as illustrated, interconnect the elevator car 12 and counterweight 26 with a one-to-one roping arrangement, wherein they are directly connected to the crossheads of the elevator car 12 and counterweight 30, but a twoto-one roping may be used for either the car, or counterweight, or both, if desired.

Compensation for the weight of the hoist ropes is provided, according to the teachings of the invention,

by a chain 32 and a compensator sheave 36 disposed below the travel path of the car 12, i.e., in the bottom part 38 of the hoi'stway l4, commonly referred to as the pit, with the compensator sheave 36 being mounted for rotation about its axis 37. Buffers for the car and counterweight 30 are also disposed in the pit, but they are not shown as they may be conventional.

Sheave 36 is constructed according to the teachings of the invention to reduce the operating noise of the chain 32, to prevent sway of the chain 32 'at all elevator speeds, and to accomplish these silencing and guiding functions without incurring offsetting economic penalties such as excessive initial cost, increased maintenance, or both. Sheave 36 is also constructed to achieve theseresults when used with elevator speeds up to about 700 feet per minute, allowing chain compensation to be used at elevator speeds at which only rope compensation was heretofore considered practical.

FIGS. 2 and 3 are side and end elevational views, respectively, of sheave 36, which views are shown partially cut away in order to more clearly illustrate the teachings of the invention.

Except for its outer periphery, sheave 36 may be'of any suitable conventional construction, including a cylindrical outer metallic member 40, an inner metallic structure 41 having a opening for receiving a shaft 42 upon which the sheave 36 is rotatably mounted, and means shown generally at 44, such as a web or plurality of spokes, for supporting member 40 from the inner structure 41.

Elastomeric means 50 is disposed about the outer peripheiy of cylindrical member 40, providing a circumferential groove 52 about the outer periphery of the sheave 36.

Elastomeric means 50 includes first and second axially spaced

members

54 and 56 which are disposed between plate-like

metallic guide members

58 and 60.

Guide members

58 and 60, which may be washer or disc shaped, are firmly secured to opposite sides of the cylindrical member 40, such as by screws 62, to form a circumferential trough or channel about sheave 36.

The construction of the elastomeric means 50 and its dimensional relationship with the chain 32 may be more readily apparent by observing cross-sectional views of the elastomeric means and chain, with the elastomeric means 50 constructed according to different embodiments of the invention in the different views. I

Specifically, FIG. 4 is a cross-sectional view of elastomeric means 50 and chain 32 taken between and in the direction of arrows IV-IV as illustrated in FIG. 2. The first and

second members

54 and 56 are independent in this embodiment, i.e., not connected to one another, each having a circular cross-sectional configuration, and each formed of a solid rod of elastomeric material. The elastomeric material is preferably polyurethane, because of its excellent wear characteristics, but any suitable elastomer may be used. The members are each formed into a continuous loop having an inside diameter equal to the outside diameter of the cylindrical member 40. The outside diameter of the material from which

members

54 and 56 are formed is selected to provide a gap between the

members

54 and 56 when these members are placed within the channel formed by

guide members

58 and 60 and axially spaced such that they contact the

guide members

58 and 60, respectively.

The chain 32 is an ordinary link chain having a series of interconnected metallic links, with alternate links 72 being of like orientation, and the intervening links 74 being of like orientation. The centerline 76 through the opening of link 72 extends in the same direction as and parallel to the centerline 37 of the sheave 36, while the centerline 78 of link 74 extends in a direction perpendicular to the direction of centerline 37. The alternate links 72 extend edgewise into the circumferential groove 52 provided by gap 70, while the intervening links 74 lie flatwise on the outer peripheries of

membe'rs

54 and 56. The edgewise dimension of the links .72, which is the dimension of the stock from which the links are made, is about the same as the dimension of gap 70, and there may be a slight interference fit between the link stock and the dimension of gap 70 in order to accommodate different sizes of chains without modification of the sheave, and still provide a positive guide for the edgewise oriented links 72. As illustrated in FIG. 4, the imaginary lines 80 and 82 of the stock which forms the two sides of link 74, which lines are parallel with the centerline 78 of the opening of link 74, extend through the axes of

members

54 and 56, but different sizes of chains may vary this relationship somewhat while still resting the sides of the intervening links against the outer peripheries of

members

54 and 56. A line 84 disposed through the axes of

members

54 and 56, which line is perpendicular to lines 80 and 82, intersects the axis of the side of link 72 which extends into the circumferential groove 52, but this dimensional relationship may change slightly with different sizes of chains, and with the compression of the resilient elastomeric material due to the tension of the chain 32 produced by the weight of the sheave 36 and by any auxiliary bias means which is used to provide the desired tension in the chain. It is important to note that the side of link 72 which extends into the circumferential groove 52 does not contact the bottom 90 of the groove, that the edgewise links 72 are positively guided by the sides of

members

54 and 56 which define the grooves, and that the links 74 do notextend into the groove but are supported flatwise on the outer peripheries of the

members

54 and 56. These relationships are necessary in order to provide a sheave which will guide the chain 32 without any tendency of the chain to ride up out of the groove and without any digging or scraping contact between the chain and the elastomeric material which would excessively wear and severely shorten the useful operating life of the sheave. It will also be noted that these relationships may be maintained for any given sheave dimension for a predetermined range of chain sizes. In other words, it is not necessary to provide a sheave for each chain size, as a given sheave will accommodate more thanone chain size.

As hereinbefore stated, the sides of the flatwise oriented links 74 bear against the

members

54 and 56 with apredetermined force determined by the amount of tension the compensation system is designed to introduce into the chain. This force against

members

54 and 56 compresses the resilient elastomeric material from which the

members

54 and 56 are formed, to provide a substantially elliptical cross-sectional configuration in the portions of

members

54 and 56 which are under the pressure points. The dimension of gap 70 is thus reduced at these pressure locations to even more firmly grip the sides of the links 72 and to perform this gripping function over a predetermined range of chain sizes. FIG. 5 is a cross-sectional view which is similar to that of FIG. 4, except the elliptical cross-sectional configuration of the elastomeric members when stressed is promoted by forming the

members

54 and 56 from tubular material, which enables them to be compressed more easily for any given chain force against their outer peripheries. Since

members

54 and 56 are modified in FIG. 5, they will be referred to as members 54' and 56' when describing this embodiment.

Members 54' and 56' define

central openings

92 and 94, respectively, with the wall thickness being selected to provide the desired compression of members 54' and 56', and thus the desired dimensional change of the circumferential groove 52, as the members 54' and 56' are compressed or stressed.

FIG. 6 is a view which is similar to that shown in FIG. 5, with FIG. 5 representing the relationship of the chain 32 and elastomeric means 50 just prior to the chains compression of the elastomeric means, and FIG. 6 represents their relationship after members 54' and 56' are compressed. It will be noted that the central axis 91 of the side of chain link 72 which extends into the circumferential groove 52 moves downwardly by a dimension 96. The movement of the axis 91 oflink 72 below the

axes

93 and 95 of members 54' and 56, respectively, as viewed in FIG. 6, is desirable as it exerts an even greater aligning force on the links 72. The sides of the members 54' and 56' which define the gap dimension 70 of groove 52 tend to pull the chain links 72 towards the bottom 90 of the groove.

While the members of the elastomeric means 50 which define the circumferential groove in the sheave 36 may be independent members, they also may be part of an integral structure which may be formed such as by extruding the elastomeric material through a die having the desired configuration. Embodiments of the invention in which

members

54 and 56 are portions of a single unitary structure are illustrated in FIGS. 7 and 8. Since elastomeric means 50 is an entirely different structure in FIG. 7, it will be referred to as elastomeric member 100. Elastomeric member 100 includes

solid projections

102 and 104 which extend outwardly in spaced relation from a common side of a back portion 106. Elastomeric member 100 has a smooth inner surface defining a diameter selected to snugly fit the outside diameter of the cylindrical member 40. The

projections

102 and 104 preferably have a substantially circular cross-sectional configuration, except of course where they are connected to the back portion 106, and they function as hereinbefore described relative to the embodiment of the invention shown in FIG. 4. The

members

102 and 104 may function to reduce the gap dimension solely by compression of the members by the flatwise oriented links 74, in which event the bottom of the groove would be disposed in the location illustrated by the broken line 110, which location is substantially tangent to the circular configuration of

members

102 and 104. The reduction in the width of the of the circumferential groove 52 may also be accomplished by a combination of compression and cantilever bending of

members

102 and 104, if desired, by lowering the bottom of the groove to the location indicated by reference numeral 112 in FIG. 7.

FIG. 8 illustrates an embodiment of the invention which is similar to the embodiment shown in FIG. 7, except

members

102 and 104 are hollow or tubular. Since member is modified in this embodiment, it is referred to as elastomeric member 100', and its extensions are referred to with

reference numerals

102 and 104. As illustrated, projections 102' and 104 define

central openings

114 and 116, respectively, and they function as hereinbefore described relative to the embodiment of the invention shown in F I65. 5 and 6.

If it is desired to tie or lock down the sheave 36, such that the sheave 36 cannot move upwardly beyond a predetermined point, any conventional lockdown arrangement may be used, or the lockdown arrangement disclosed in co-pending application Ser. No. 347,285, filed Apr. 2, 1973, which is assigned to the same ass'ignee as the present application, may be used. A compensation system with a lockdown feature, as is well known in the art, applies a predetermined tension to the compensating rope or chain while automatically accommodating permanent and elastic changes in the length of the hoisting rope. The upward movement of the sheave, however, is limited, in order to tie the car and counterweight together to achieve similar rates of deceleration for both the car and counterweight during a buffer stop of either, or a safety stop of the car.

FIG. 9 is a perspective view of an elevator system which includes tensioning and lockdown apparatus 122 which may utilize the teachings of the invention hereinbefore described. In this embodiment, an elevator car 124 and counterweight 126 are interconnected by hoist roping 128 which is reeved about a traction sheave (not shown), with the traction sheave being driven by drive means shown generally at 130. Two

ordinary link chains

132 and 134 are used to provide compensation for the hoist roping 128, with the chains being ,connected to points spaced equally on opposite sides of the center gravity of the car, and to similar points on the counterweight. The spacing 136 between the two chains may be any suitable dimension. The car and counterweight buffers may be disposed between the chains, in which event the dimension 136 would be greater than illustrated in H0. 9.

Each chain has the ends of its loop spread by a dimension which is much greater than would be provided by a natural loop, to provide good car balance, without requiring the use of a sheave having the necessarily large diameter required to achieve this spread. This resuit is obtained by using two smaller diameter sheaves for each chain. The distance between the axes of these smaller diameter sheaves is made adjustable so that the desired chain spread may be obtained without changing the construction of the sheaves themselves.

Specifically, chain 132 is disposed to run about first and

second sheaves

140 and 142, and chain 134 is disposed to run about first and

second sheaves

144 and 146, with these sheaves each being constructed as hereinbefore disclosed relative to sheave 36 shown in FIG.

.2. Sheaves 140 and -144 are mounted for rotation on a mension 152 between

axes

148 and 150 is selected for each application, and is adjustable so field changes may be made, if necessary.

Sheaves

140, 142, 144 and 146 are mounted on a common frame 160, and the frame 160 is pivotable about axis 162 in a vertical plane. Frame 160 may be constructed of two spaced

angles

164 and 166, with a plurality of openings 168 disposed in the facing portions of the angles for rotatably mounting the sheaves and for adjusting the dimension 152 between the sheaves. Means for pivoting the frame 160 is provided at one end thereof, such as a hinge for each angle, with ahinge 170 for angle 164 being illustrated in the figure. One side of the hinge 170 is connected to the angle 164, and the other side is fixed to a vertically extending mounting member, such as angle 172. in like manner, a hinge would be connected to angle 166, and to a vertical mounting member or angle 174.

The frame 160 is biased downwardly about the pivot axis 162 by any suitable biasing means, such as compression springs 176 and 178, but a single spring may be used if desired.

Rod members

180 and 182 each have one end fixed to

angles

172 and 174, respectively, and they extend through openings in

angles

164 and 166, through

lower spring seats

184 and 186, through

springs

176 and 178, and through openings in upper spring seats 188 and 190, respectively. The outwardly extending ends of the

rod members

180 and 182 are threaded, and

nuts

192 and 194 are disposed thereon and advanced to the point necessary to urge the upper spring seats 188 and 190 against the springs in order to compress them and provide the proper bias, and thus the desired tension in the

chains

132 and 134. Elastic and permanent stretch of the hoisting rope is automatically accommodated, and upward movement of the sheaves is limited when the

springs

176 and 178 pipe, to prevent slack in the chains due to buffer and safety stops.

In summary, there has been disclosed a new and improved elevator system of the traction type which successfully extends chain compensation for the hoisting ropes to elevator systems which operate at speeds up to about 700 feet per minute, by reducing chain noise and eliminating chain sway without offsetting economic penalties, either in initial cost or higher maintenance costs. The compensating chain is firmly guided by a sheave which has a groove formed of spaced elastomeric members, with alternate links of the chain extending edgewise into the groove, and with the intervening links resting flatwise on the outer peripheries of the elastomeric members, outside the circumferential groove. This arrangement provides the silencing and guiding functions without scraping, digging and twisting of the chain links, thus providing a low cost, long life, low maintenance compensation system.

We claim as our invention:

1. An elevator system, comprising:

an elevator car,

a counterweight,

motive means for said car and counterweight including hoisting roping interconnecting said car and counterweight,

a compensating chain having a plurality of interconnected links, said compensating chain interconnecting said car and counterweight,

tensioning means for tensioning and guiding said compensating chain,

said tensioning means including a sheave and elastomeric means,

said elastomeric means including first and second axially spaced members disposed about the outer periphery of said sheave to define a circumferential groove therein having a predetermined width dimension,

said first and second members of the elastomeric means being shaped and spaced such that alternate links of said compensating chain extend edgewise into the circumferential groove, contacting the spaced opposed sides of the first and second members, and the intervening links of said compensating chain rest against the outer peripheries of said first and second members.

2, The elevator system of claim 1 wherein the first and second members of the elastomeric means are independent, each having a substantially circular crosssectional configuration.

3. The elevator system of claim 1 wherein the first and second members of the elastomeric means are independent, tubular members.

4. The elevator system of claim 3 wherein the first and second tubular members are dimensioned such that the tensioned compensating chain compresses a portion of each of the tubular members into a substantially elliptical cross-sectional configuration, reducing the width dimension of the circumferential groove.

5. The elevator system of claim 1 wherein the elastomeric means includes a base portion, with the first and second members of the elastomeric means being integrally connected to and extending outwardly from said base portion.

6. The elevator system of claim 5 wherein the first and second members each have a substantially circular cross-sectional configuration.

7. The elevator system of claim 6 wherein the first and second members are tubular.

8. The elevator system of claim 1 wherein the tensioning means includes support means pivotally mounted at a point located below the travel paths of the elevator car and counterweight, with the sheave being rotatably mounted on said support means, and

port means permits limited pivotal movement thereof, preventing movement which attempts to raise the sheave beyond a predetermined point.

Claims

1. An elevator system, comprising: an elevator car, a counterweight, motive means for said car and counterweight including hoisting roping interconnecting said car and counterweight, a compensating chain having a plurality of interconnected links, said compensating chain interconnecting said car and counterweight, tensioning means for tensioning and guiding said compensating chain, said tensioning means including a sheave and elastomeric means, said elastomeric means including first and second axially spaced members disposed about the outer periphery of said sheave to define a circumferential groove therein having a predetermined width dimension, said first and second members of the elastomeric means being shaped and spaced such that alternate links of said compensating chain extend edgewise into the circumferential groove, contacting the spaced opposed sides of the first and second members, and the intervening links of said compensating chain rest against the outer peripheries of said first and second members.

2. The elevator system of claim 1 wherein the first and second members of the elastomeric means are independent, each having a substantially circular cross-sectional configuration.

8. The elevator system of claim 1 wherein the tensioning means includes support means pivotally mounted at a point located below the travel paths of the elevator car and counterweight, with the sheave being rotatably mounted on said support means, and means biasing said support means to tension the compensating chain.

9. The elevator system of claim 8 whErein the pivotal movement of the support means is in a substantially vertical plane, and wherein the means biasing the support means permits limited pivotal movement thereof, preventing movement which attempts to raise the sheave beyond a predetermined point.