US1940249A - Device for equalizing strains on hoisting ropes - Google Patents

Description

Dec. 19, 1933. J. E. EVANS DEVICE FOR EQUALIZING STRAINS ON HOISTING ROPES Filed Dec. 3. 1931 2 Sheets-Sheet l J. E. EVANS Dec. 19, 1933.

DEVICE FOR EQUALIZING STRAINS ON HOISTING ROPES Filed Dec. 3. 1931 2 Sheets-Sheet 2 Patented Dec. 19, 1933 DEVICE FOR EQUALIZING STRAINS ON .HOISTING ROPES Joseph E. Evans, Bedford, Ind., assignor to Evans Elevator Equalizer Company, Bedford, Ind., a corporation of Indiana Application December 3, 1931. 'Serial No. 578,625

16 Claims. (01. 18'71) My invention relates to a device for equalizing strains which, in the particular embodiment hereinafter described, was more particularly designed for use in connection with hoisting cables employed for raising and lowering elevator cars carrying passengers or freight from one floor to another of buildings, especially tall buildings of the sky-scraper type developed in recent years. In such installations it is commen practice to employ a group of wire cables connected at one end to the car and 'at the other end to a counterweight, and tracking in peripheral grooves in a suspension drum, or pcwer-driven hoisting drum, at the top of the elevator shaft. As is already well understood, a tendency to unequal travel .of the cables over the hoisting drum is apt to arise from unavoidable inequality in the depth of the grooves of the pulley, or differences in the size of the cables,

or the amount of stretch which they exhibit from various causes, and means for permitting such variation in travel while maintaining an equal tension .on all the cables is highly important. It is the object of my invention to 5 provide an improved strain-equalizer for such use of the type employing floating pulleys severally connected to the cables and an equalizing cable engaging in alternation such fioating pulleys .and a set of lower pulleys secured to the car, which shall have certain novel and desirable features of construction in the arrangement of the two sets of pulleys, the construction of a block member providing bearings for the lower pulleys and an associated retaining plate, a 5 pulley block and connected safety bolt which provides also a bearing abutment for certain biasing springs employed in the device, and in other details in the construction and arrangement of the parts of the device which will be apparent from the description hereinafter given.

Among the objects of my invention may be mentioned the biasing springs before referred to, operating in a novel manner to yieldingly stress the hoisting cables in such a way that they will tend to return to a pre-adjusted uniform normal position with reference'to their attachment to the car and counterweight. With the ends indicated in view I have devised and invented the equalizing suspension device hereinafter described in.- detail, the essential elements of my invention being more particularly pointed out in the appended claims. v

In the drawings, Figure 1 is a side view of fragments of an elevator car and a counterweight connected to each other by means of hoistingcables running over a hoisting drum and secured to the car and counterweight by means of my novel equalizing devices;

Fig. 2 is a front view of the form of equalizer secured to the counterweight;

Fig. 3 is a side view of the same; v

Fig. 4 is a horizontal section of the device just above the floating pulleys, the plane of the section being indicated by the dotted line 4-4 of Fig. 2; 6

Fig. 5 is a horizontal section on the line 55 of Fig. 2; v

Fig. 6 is a fragmentary section in a plane indicated by the dotted line 6--6 of Fig. 5;

Fig. 7 is a fragmentary section of the same parts as indicated by the dotted line 7-7 of Fig. 6, showing the plane of the section;

Fig. 8 is a vertical section extending transversely of the supporting beams of the car (as counterweight), illustrating a modified form of bearing casting for rotatably supporting the equalizing pulleys secured to the car; and

Fig. 9 is a second modified form of bearing block which may be employed for the same purpose.

Like-reference characters indicate like parts in all the figures of the drawings.

For reasons which will later be explained I connect the group of hoisting cables connecting the car and counterweight at the end only (as the counterweight end) by means of an equalizing device provided with biasing springs, while at the opposite end they are connected by means of a device which is, or may be, substantially the same, excepting that it is not provided with biasing springs. In the construction illustrated, the car A, a fragment of which is shown, is connected by one of my novel equalizingdevices B with the group of hoisting cables 0 which run in grooves in the hoisting drum D and idler drum E in a manner well-known in elevator installations, the other end of the cables being connected to the counterweight F by the equalizer G, which is of the same construction as the equalizer B, excepting for the additional provision of biasing springs, as before mentioned, and as will later be described in detail.

Describing first the construction of the equalizer G, it will be understood that the frame of the counterweight (or of the car, in case the arrangement should be reversed) includes ordinarily, and as shown, a pair of parallel channeliron beams 1-1 which are spaced apart a proper distance to provide for the reception .between them of a bearing-block member 2 which n A o u in the form of my invention illustrated in Figs. 1 to 3 is a metal casting flanged at the top and formed with bolt holes arranged to receive clamping bolts 3 which engage also orificed cross-bars 4 below the beams l and serve. to secure the bearing block to the car.

As best shown in Figs. 6 and 7 the blocks 2 are formed with vertical slots whichextend through them from top to bottom the overlapping zigzag order shown in Fig. 5, and which are of proper size to receive the lower or equalizing pulleys 6, five in number in the present case. These pulleys are pivotally mounted upon bearing pins 7 which extend through them and project on both sides into opposite semi-cylindrical seats formed at the top of vertical recesses 8 which extend in opposite directions from the faces of the slots 5. Below the bearing pins 7 of the pulleys 6, in the recesses 8 mentioned, are arranged filler blocks BZ'preferably of wood by means of which the pins are firmly secured, in place and prevented from rotating. To the bottom of the casting l is bolted a retaining plate 9 which servesto clamp the filler blocks in position and prevents disengagement of the parts when assembled.

It may here be explained that the hoisting cables C, six in number in the present instance, are individually connected to the members of a set of upper, floating pulleys 10 which are engaged in loops of an equalizing cable 11 anchored at its ends by rope socket blocks 12 to the associated retaining plate and bearing block,

. and consequently to the counterweight (or car) frame, as shown in Figs. 2 and 3.

Describing next the parts associated with the hoisting cables and floating pulleys 10, each cable C is secured to a threaded socket block 13 which is connected by a right-and-left threaded adjusting bolt 14 with the threaded shank of a pulley block 15 formed with parallel side portions 1'7 between which the'associated pulley is pivotally mounted, lock nuts 16 being provided to secure the parts together in adjusted relation.

Preferably, and as shown, the side portions 17 of each pulley block 15 extend downwardly in the form of a pair of elongated ears between the lower ends of which is pivotally mounted the upper eye portion of a safety bolt lawhich below extends loosely through orificesin the block 2 and retaining plate 9. The opening between the portions 17 of the pulley block provides space for the threading of the equalizing cable 11 through the block after the cable has been cut to proper length and equipped with sockets, the pulley being removed for this purpose. However, if desired .the lower end of the portions 17 may be connected, sufficient space for threading the equalizing cable being otherwise provided. At its lower threaded end each bolt carries nuts 19 which serve to adjustably confine between it and the retaining plate above it a coiled compression biasing spring 20 which under its intended normal adjustment is not under any tension, but just contacts the retaining plate and the upper nut. The nuts 19 at the lower end of the safety bolts form heads for the latter whichin case the equalizing cable should break will bring up against the bearing block 2, the springs 20 in such case acting as buffer members.

While I regard the jointed flexible connection provided by the ears 17 of the bearing block 15 and the eye of the bolt 18 as desirable, it will be understood that a rigid connection of the bearing member and bolt may be provided if preferred. Also, it will be understood that means for preventing rotation of the connected parts while permitting a vertical sliding movement of the bolts 18 with relation to parts stationarily secured to the counterweight, or car, as by a ieathered connection, or its equivalent, may be provided if desired.

The floating pulleys 10, like the lower pulleys 6, are arranged in front and rear rows in overlapping inclined relation, in such manner that the equalizing cable 11 will track vertically from its point of anchorage underneath the right side of the right member of the group of upper pulleys and adjacent the right end of the group of lower pulleys, as viewed in Fig. i, to the groove of said right hand upper pulley, and then in succession will track in vertical stretches between the lowerand upper pulleys in a zigzag path to its point of anchorage adjacent the left end of the group of lower pulleys and directly underneath the left side of the left upper pulley. The arrangement is such that the loops of the equalizing cable engaged bythe upper pulleys will extend alternately forwardly of and rearwardly of the longitudinal center line of the group of such upper pulleys in staggered and oppositely inclined overlapping relation.

As above explained the lower pulleys, which are. likewise staggered and oppositely inclined from. the longitudinal center line of the group, but at a different angle of inclination, are so arranged that the reaches of the equalizing cable between the upper and lower pulleys track vertically, and from this different inclination of angles and the staggered overlapping relationship of the parts it results that the loop of the cable around each upper pulley tracks in one reach into a pulley on one side (front or rear) of the device and in the other reach into a pulley on'theopposite side of the device-01 to an anchorage at the ends-and from each lower pulley the equalizing cable likewise tracks into an upper pulley on one side and another upper pulley on the opposite side of the device.

Inasmuch as the space between the channel- .ii'on beam members which constitute the crosshead of the car frame is in some makes and. styles of elevators quite narrow, it is obvious that the inclined and staggered relationship of the pulleys is of great utility in enabling the lower pulleys, to be compactly arranged and capable of installation in the space between the pulleys of greater diameter to be employed in a given space than by any other arrangement known to me. The pulleys shown in the rangement illustrated are approximately of the same size and if desired pulleys of precisely the same diameter may be used by slight modification of proportions, while retaining the same arrangement. It is obvious that where space permits a widening of the casting pulleys of greater iameter may beused, and also that the angles of inclination, as well as the diameter of the biasing springs are unnecessary.

pulleys, may be changed as necessary 01' desired to vary the spacing of the rope centers.

The equalizing device used at the car end of the. hoisting cables (marked B as a whole in Fig. 1) differs from the equalizer above described only in that the springs 20 are omitted, and that due to the omission of the springs the bolts 18 are somewhat shortened.

It will be understood that in the usual functioning of the device, inequalities in size of parts or degree of stretch in the hoisting cables will be taken up by a shifting of relative vertical position of the upper pulleys as the cables run in one direction over the suspension drum,

and that the causes producing unequal travel of the hoisting cables will act in the reverse direction to restore the pulleys to their original position as the car moves in the opposite direction and returns to its first position. So far as these conditions are concerned, therefore, the It has been found, however, that in some cases one or more of the hoisting cables may tend to creep in one direction or the other in its groove in the suspension drum, probably because of unequal twist in the cables, or slippage from other reasons not fully understood. In any case, whether with or without creeping or slippage, any difference in the horizontal position of the pulleys of that one of the equalizer provided with biasing springs acts to put the spring of any oneor more of the pulleys standing higher than its normal position of equal horizontal adjustment under a compressive strain acting on the particular hoisting rope in the same direction as the stress of gravity exerted through the equalizing cable on the pulley connected to such rope, and the spring thus takes up a part of the weight of the car and correspondingly relieves the weight on the remaining cables.

The total weight of the car is accordingly in part taken up severally by such springs as are under compression and these portions communicated directly to-the cables respectively stressed by the springs while the remaining weight is sustained in equal parts by the floating pulley and distributed equally among the cables. The expansive stress of any particular spring under compression manifestly tends to restore the connected pulley to its normal position in which the spring is uncompressed, although to an extent deter-mined by the strength of the springs, their effect is to prevent perfect equalization of the strain on the hoisting cables. I therefore employ them upon one end of the cables only, --preferably the counterweight end,-since in the travel of the car and counterweight from one extreme posiheight above the lower pulleys.

The arrangement of the channel iron frame members of the car (or counterweight) through which my equalizing device is secured to the car vary in elevator cars of different sizes and makes, and it is desirable to provide means for adapt- The perfecting my device to cars differing in construction. In Fig. 8 I have shown the position. and arrangement of a bearing block for the lower pulleys, marked 30, which may be installed between the channel members 1 of thecar frame, and secured in position by bolts 31 equipped with nuts engaging the bearing block structure and cross-bars 5-5 above and below the members 1.

In Fig. 9 I have shown a differently formed bearing block 32, formed with flanges 33 on its lower side extending beneath the channel iron frame members 1, and secured to such members by clamping bolts 34 engaging the cross-bar 5 above said frame members.

I claim: v I

l. A suspension device for connecting an elevator car to a group of hoistingropes including a plurality of floating pulleys severally connected with the hoisting ropes, a plurality of other lower pulleys one less in number than said floating pulleys pivoted to the car, and an equalizing cable anchored at both ends to the car and engaging said floating pulleys and lower pulleys in alternation, said floating pulleys being arranged in front and rear rows disposed in staggered relation and said lower pulleys being also disposed in front and rows in staggered relation, the arrangement being further such that said equalizing cable will track between said pulleys in vertical reaches from one point of anchorage adjacent one end of said group of lower pulleys to its other point of anchorage adjacent the opp0- site end of such group of lower pulleys in a generally'zigzag path in loops extending in alternate order between said front and rear rows of pulleys.

2. A suspension device according to claim 1 "n wl1ich the pulleys of one rowv of one set of ulleys are inclined from the longitudinal center ne of the device oppositely with respect to the ulleys of the other row.

3. A suspension device according to claim 1 in which the pulleys of one row of each set of pulleys are inclined from the longitudinal center line of the device oppositely with respect to the pulleys of the other row of the particular set, and in which the angle of inclination of the pulleys of one'set differs from that of the other set.

'4. A suspension device according to claim 1 in which the outer reach of each loop of the equalizing cable engaging a lower pulley tracks into a floatin pulley on the same side of the device and the inner reach tracks into a floating pulley on the other side. I

5. A suspension device according to claim 1 in which the outer reach of each loop of the equalizing cable engaging a lower pulley tracks into a floating pulley on the same side of the device and the inner reach tracks into a floating pulley on the other side, and in which the inner reaches of theequalizing cable lie in alternate order upon opposite sides of the longitudinal center line of the device.

6. A suspension device for connecting an elevator car to a group of hoisting ropes including a plurality of floating pulley blocks individually connected to said ropes and floating pulleys in said blocks, an orificed bearing block secured to the car, other lower pulleys pivotally mounted in said bearing block, an equalizing cable anchored to the car and engaging said floating and lower. pulleys in alternation, and headed safety bolts severally secured to said pulley block and slidably passing through orifices in said bearings block.

7. A suspension device for connecting an elevator car to a group of hoisting ropes including a plurality of floating pulley blocks individually connected to said ropes and floating pulleys in said blocks, an orificed bearing block secured to the car, other lower pulleys'pivotally mounted in said bearing block, an equalizing cable anchored to the car and engaging said floating and lower pulleys in alternation, headed safety bolts severally secured to said pulley block and slidably passing through orifices in said bearing block, and buffer member between said bolts and bearing block.

8. A suspension device for connecting an elevator car to a group of hoisting ropes including a plurality of floating pulley blocks individually connected to said ropes and floating pulleys in said blocks, an orificed bearing block secured to the car, other lower pulleys pivotally mounted in said bearing block, an equalizing cable anchored to the car and engaging said floating and lower pulleys in alternation, headed safety bolts severally secured to said pulley block and slidably passing through orifices in said bearing block, and compression springs arranged severally on said bolts between the heads thereof and said bearing block.

9. A suspension device for connecting an elevator car to a group of hoisting ropes including a plurality of floating pulley blocks individually connected to said ropes and floating pulleys in said blocks, an orificedbearing block secured to the car, other lower pulleys pivotally mounted in said bearing block, an equalizing cable anchored to the car and engaging said floating and lower pulleys in alternation, and safety bolts severally pivoted to the lower ends of said pulley blocks and headed at their lower ends, said bolts being arranged to slidably pass through orifices in said bearing block.

10. A suspension device for connecting an elevator car to a group of hoisting r0 es including a plurality of floating pulley blocks individually connected to said ropes and floating pulleys in said blocks, an orificed bearing block secured to the car, other lower pulleys pivotally mounted in said bearing block, an equalizing cable anchored to the car and engaging said floating and lower pulleys in alternation, headed safety bolts severally secured to said pulley block and slidably passing through orifices in said bearing block, and compression springs interposed between the heads of said bolts and said bearing block, said springs being in normal position of the parts under no stress.

' 11'. The combination, in an elevator system including a car and a counterweight, of a plurality of hoisting ropes, a hoisting drum engaged by said ropes, an equalizing device connecting said ropes at one end to said car, and a second equalizing device connecting said ropes at the other end to said counterweight, one only of said equalizing devices including biasing means tending to yieldingly maintain the hoisting ropes in a certain position of longitudinal relationship to each other.

12. The combination, in an elevator system including a car and a counterweight, of a plurality of hoisting ropes, a hoisting drum engaged by said ropes, an equaiizing device connecting said ropes at one end to said car, and a second equalizing device connecting said ropes at the other end to said counterweight, the equalizing device connected to said counterweight only including biasing means tending to yieldingly maintain the hoisting ropes in a certain position of longitudinal relationship to each other.

13. The combination, in an elevator system including a car and a counterweight, of a plurality of hoisting ropes, a hoisting drum engaged by said ropes, an, equalizing device connecting ropes at one end to said car, and a second equalizing device connecting said ropes at the other end to said counterweight, the equalizing device connected to said counterweight including springs severally connected to the ropes, said springs being in normal position of the ropes under .no stress and upon relative longitudinal shifting of the position of the ropes being individually tensioned in opposition to a movement shortening the particular rope.

14. In an equalizing device for connecting hoisting ropes to an elevator car, said device including upper and lower sets of pulleys connected by equalizing rigging, means for pivotally securing the pull ys of said lower set to the car including a cast metal bearing block arranged'to be secured between car frame members, said block being formed with two rows of inclined staggered vertical orifices arranged to receive the pulleys. I

15. In an equalizing device for connecting hoisting ropes to an elevator car, said device including upper and lower sets of pulleys connected by equalizing rigging, means for pivotally securing the pulleys of said lower set to the car including a cast metal bearing block arranged tobe secured between car frame members, said block being formed with two rows of inclined staggered vertical orifices arranged to receive the pulleys, and the side walls of said orifices being formed with vertical grooves extending upwardly from the bottom of the casting to the axis of the pulley, and pivots fixed in said blocks at the top of said grooves.

16. An equalizing device having the structure recited in claim 15 in which filler blocks are arranged in the vertical grooves mentioned in said claim and a retaining plate is secured to the bearing block below said filler blocks.

JOSEPH E. EVANS.

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