US1700587A

US1700587A - Cable equalizer for elevators

Info

Publication number: US1700587A
Application number: US223011A
Authority: US
Inventors: Ray P Higbee
Original assignee: Westinghouse Electric and Manufacturing Co
Current assignee: CBS Corp
Priority date: 1927-09-30
Filing date: 1927-09-30
Publication date: 1929-01-29
Anticipated expiration: 1946-01-29

Description

R.. P. HIGBEE CABLE EQUAL IZER FOR ELEVATORS Flled Sept 30, 1927 Jan. 29, 1929.

INVENTOR 541/ P Hiybee T'i' RNEY Patented Jan. 2a, 1929.

RAY P. HIGBEE, or PrrILAnnLriara, rniamsyrverna.Assrsuon To wrisamaueusn ELECTRIC &. MAnUrAo'i-Umne GOMEANY, .a eonren-A'rmnor PENESYLVANIA- CABLE EQUALIZER FOR ELEVATORS.

Application filed es -amber 30, 1-927. Serial No. 223,011.

My invention relates to equalizers for distributing a load drawn by or supported by a plurality'of drawing or supporting devices in such manner that each of the drawing or supporting devices will receive an equal amount of the load. invention has special reference to equalizers for elevators, hoists and similar machinery wherein the load is supported upon a plurality ofcables.

An objectof my inventionis to provide a device for distributing the total load equally 1 between a plurality of draft devices.

Another object of my invention is to provide a cable equalizer for the above stated purposes which is simple in construction, and has a minimum of parts. 7

Another object of my invention is to provide a cable equalizer system forelevators wherein the distribution of the load upon each of the cables is achieved by a division of load, both at the counterweight and at the elevator cab structure. v

My invention will be described with referonce to the accompanying drawing, where-- in 4 Figure 1 is a perspective View of a portion of my cablebqualizing device attached to the superstructure of the elevator cab,

Fig. 2 is an end view of the assembly of my cable-equalizing device attached to the superstructure of the elevator cab; and r Fig. 3 is a side elevation of'a cable-equalizing device which I propose to use on the elevator counterweight.

In modern elevator equipment, it is usual to employ a cab of such weight and designed to carry such loads that it is not feasible to support the cab structure upon a single cable. Hence, it has long been the practice to use a number of supporting cables, ranging from 2 to 8 or more cables per elevator. These cables are attached to the supporting structure of the elevator cab andare tensioned when installed to equalize the load upon the several cables. This tensioning is extremely inaccurate at the initial installation of the cables, since the only manner in which the tension may be tested is to compare the resistance to turning of the locking nuts as each of the cables is drawn taut.

It is well known that after a few days service the cables stretch to their extreme normal length, after which any further stretching is dependent upon theweight placed upon the cab and the elasticity of the cables. This initial stretching is not uniform in allcof the cables, varying between the several cables in extreme degrees. Thus, a'few days after installation of cables, thetens'ion on each of the cables has undergone a great change, regardless of the care which may have been taken in the initial installation.

' The result of the change in the tensioning of the cables as previously described is that one of the cables is tensioned to a greater amount than the others and the'tension of each cable varies with reference to the remainder, so that only one or two out of a total of 4, 6 or'8 cables does the actual work of supporting the load.

' Various devices have been designed time to time to overcome this fault 'an-dto automatically'adjust the load upon the cables the stretching occurs. "However, these devices usually comprisea complicated system of levers, rollers or other devices, the cost of manufacture and the delicacy of adjustment of which render their use impracticable.

Ipropose to use a simple system of levers based upon the well-known principle'of moments of force varying according as the load is placed closer to, or farther from the fulcrum.

Referringto Fig. 1, I have'illustrateda portion of the structure of an elevator cab,

ordinarilycomprising a pair of spaced apart channel irons, one of which is designated as l 1 and shown in full lines, the other of which is designated as 2' and is shown'in dotted lines. These spaced apart channel irons extend across the top of the elevator cab and have attached thereto the remainder of the supporting structure {not shown) for the.

elevator cab platform in a manner wellknown in the elevator art. An opening 3 in the channel iron member 2 receives therethrough a supporting bar 4 which extends through a similar, alinedopening 5 in the other channel member 1. Between the two channel members 1 and 2', the supporting bar 4 passes through openings in each of two telescoping equalizing members designated as 6 and 7.

The equalizing member 7 comprises a U- .shaped element having a solid portion 8 and two relatively'narr-ow legs 9 and 10 extend- The other equalizing member 6 comprises an elongated member formed of squared stock and is provided with

tapered openings

17 and 18 near the ends of the bar, which openings correspond in form to the opening 12.

in the member 7. The bar 6 is also provided with spaced

apart openings

19 and 20 extending in a plane at right angles to the openings 1'7 and 18. The distance between the

openings

19 and 20 is the same as the distance between the openings 13 and 15 and 1A and 16 in the legs 9 and 10, respectively, of the bar 7. i

The supporting bar i extends through the opening 16 in leg 10, the opening 20 of member 6 and. the opening 15 in leg 9, and in this manner connects the equalizing member 7 in su ortin en a ement with channel iron b 21 6 members 1 and 2 and with equalizing member 6. It will be noted that the opening 20 is formed in oval cross section, slightly larger than is necessary to fit the supporting bar l,

thus permitting a slight vertical movement between the members-6 and 7. A connecting bar 21 extends through the alined openings 14 and 13 or the members 10 and 9 and also through the opening 19 of the member 6, thus pivotally connecting the extending legs 9 and 10 with the member 6.

It will be noted that the connecting bar 21 extends only so far as is necessary to pass through the members 9, 10 and 6, and does not extend into engagement with either of channel members, 1 and '2.

As a means of attaching the cables to the equalizing bars, a bolt 22 is inserted through the opening 12 in the member 7 and is secured in the opening by any suitable means, represented as a pair of nuts 23 and 2st. The nut 23 acts as a head tor the bolt while the nut 24 engaging the nut 23 serves as a locknut to prevent the nut from becoming loosened, when subjected to the usual shocks occasioned by movements of the elevator cab.

The upper portion of the bolt 22 is formed with a bolt head 25 extending through an opening inthe strap 26 of a clevis 27, to which the elevator supporting cable 28 is at tached in any well known manner. This arrangement of clevis and cableis well known in the art and does not form any part of. my invention. r

Assuming, for example, that an elevator cab of such proportions and weight as to re quire the use of six cables, my device may be used to distribute the total weight of the cab equally between each of the six cables. Referring to Fig. 3, the cables, designated by the characters A, B, C, D, E and F, are secured to the counterweight 29 by means of a pivotally connected equalizing bar 30. The bar 30 is suitably supported upon the counterweight structure 29 by means of a pair of brackets 31, (only one of which is shown) through which passes a supporting pin 32, which also passes through an opening 33 in the equalizing member 30.

The supporting cables A, B, C, D, E and F are divided into groups of three, one group comprising the cables A, B and C attached to the equalizing bar 30 upon one side of the supporting pivot pin 32 in suitably tapered openings in the bar 30, such openings being designated by the

reference numerals

34, 35 and 36. The c bles A, B and C are each secured by a bolt, nut and clevis structure similar to that described with reference to Figs. 1 and 2. The remaining cables D, E and F are secured in

suitable openings

37, 38 and 39 upon the end of the bar 30 opposite to that to which the first three cables are secured.

By suitably spacing the

openings

36 and 37 at equal distances from the center of the supporting pivot pin 32, an equal distribution of the load of the counterweight may be secured. By corresponding equal spacing of the

openings

35, 38 and 34, 39, the load may be distributed equallybetween each of the two groups of cables, A, B, C, and D, E, F.

It is obvious, however, that the load be tween cables A, B and C will not be equal with this arrangement and this unbalancing of load is compensated for by the use of the second portion of my equalizing structure, on the elevator cab.

By reference to Fig. 2, it will be readily seen that the complete assembly for the. assumed number of cables necessitates the use of two of the structures shown in 1, one for each group of three'cables. Assume the use of two such structures, one of which, designated generally by the numeral 40, will act asa seeming device for one of the groups of cables, for example, A, B and C, while the other of the structures, designated generally by the numeral 1-1, may be used to secure the remaining group of cables D, E and F.

The arrangement of the cables may be such that the cable A willbe secured at the opening 17 in the member 6, the cable B may be secured in the opening 18 of the member 6 and the cable C in the opening 12 of the member 7. By properly spacing the opening 17 l a distance (X) from the center, or fulcrum point, of the connecting bar 21, equal to the distance (Y) between the opening 18 and the center of the bar 21,- it is readily by application of the simple principle of levers, that an equal distribution of the load between the cables A and B will be secured. If the distance (ltd) between the center of the supportingbar a (the fulcrum "for member?) and the opening 12 is made twice that of the distance (Nlbetween the center of the supporting bar 4 and the center of the connecting bar 21,11. further equal distribution ofthe load between the cable C and each of the cables A and B will be accomplished. Thus, half the combined counterweight and elevator cab structure. load (halved by the use of the equalizer on the counterweight) will be distributed equally between the cables A, B and C. I

By a similar location of the cables, D, E

and F on the structure 4:1,a similar distribu-.

tion of half the total load equally between each of these three cables will be achieved. Thus, the total load of the counterweight and cab will be equally distributed between each of the six cables, each cable supporting but one-sixth of the load."

In the event of a stretching of one of the cables with reference to the other, the equalizing bar to which it is attached may rotate about its pivot without varying the load upon any of the remaining cables. The elongation of either of cables A and B, causing the rotation of the member 6, will not cause any variation of the load upon cable C, by reason of the fact that the enlarged opening 20, through which the supporting pin 4 passes, by acting as a pivot for the supporting bar 7 will permit the bar 6 to rotate without changing theposition of the member 7. Similarly, elongation of the cable C, causing the rotation of the member 7' about its pivot a, will move the member 6 slightly upwardly, slackening the cables A and B to thus restore equal tension upon the three cables.

It is thus seen that n y device may be used to equally divide the load between the several cables in an elevator system, placing an equal strain upon each of the cables. It is well recognized in the elevator art that the unequal tensioning of the several cables causes one or more of the cables to wear more rapidly than the remainder; but the use of my device will prevent this undue wear upon any one of the cables and will thus increase the life of the entire set. Moreover, by equalizing the strain on each of the cables, the danger of cable breakage is obviated, thus rendering the elevator using'my device more safe in operation.

l/Vhile I have illustrated my device in combination with a system of six cables, it is readily seen that by a suitable selection of the numbers and arrangement of the pieces of apparatus shown in Figs. 1 and 2, my device may be adapted for use with any'number of cables, either an odd number or an even numbet. Itlereevearhe number of parts n eces-s sary for the-use ofmy device is relatively small and the construction extremely simple.

The embodiment of mydevice shown is merelyillustrative and I do not desire to be on each of said groupsequally between the cables of said groups.

2. I11 :1. cable equalizer for an elevator supported by a plurality of cables and substantially balanced by acounterweight,means at said counterweight for dividing the load equally between a plurality of groups of said cables, and means at said elevator for each of said 1 groups for dividing the load on each group equally between groups. i V v 3. In a cable equalizer for a system of the type wherein two members are supported in substantially balanced relation to each other by a plurality of cables, means at one of said members for dividing the total load equally between a plurality of groups of said cables, each of said groups comprising a plural odd number of said cables, and means at the other of said members for each of said the cables of said 7 groups for dividing the load on each of said groupsequally between the cables ojfsaid group.

4. In a device for distributing a load be tween a plurality of load-supporting devices, means for dividing the load equally between a plurality of groups of said supporting devices, each of said groups comprising three of said supporting devices, means for dividing the load equally between each of the supporting devices in each of said groups compris-f ing a lever, a fulcrum for, said lever, means for attaching one of said load-supporting devices to said lever at oppositesides of said fulcrum, a second lever, a fulcrum for said second lever, means for attaching the load to the fulcrum of said second lever, means for attaching one end of said second lever to the fulcrum of said first lever, and means for attaching the third of said load-supporting de vices t0 the opposite end of said second lever at a distance from the fulcrum of said second lever equal to twice the distance between the fulcrums of said levers. y

5. In a device for distributing a load" equally between three load-supporting devices, a lever,a fulcrum for said lever, means for attaching said supporting devices on o posite sides of said fulcrum and at equal distances from said fulcrum, a second lever, on said second lever equal to one third of the means for attaching one end of said second distance between thepoint of attachment of lever to the fulcrum of said first lever, means said third supporting devices and the point for attaching the third of said supporting deof attachment of said first lever. vices to the other end of said second lever, In testimony whereofflhave hereunto suband means for attaching the supported load scribed my name this 19th day of August,

at the fulcrum of said second lever, said last 1927.

mentioned fulcrum beinglocated at a point RAY 1. HIGBEE.