US1928213A - Lifting sling - Google Patents

Description

p 1933- M. SHOWERS, JR., ET AL 1,928,213

' LIFTING SLING Filed May 10, 1932 3 Sheets-Sheet 1 By Bali a L. t1 1,

ATTORNEYS.

Sept. 26, 1933.

L. M. SHOWERS, JR, ET AL LIFTING SLING 3 Sheets-Sheet 2 m NH My Hm.- I r M E Q! a Lewzsimsiw 7 im INVENTOR iWI/a ATTORNEYS.

Sept. 26, 1933.

L. M. SHOWERS, JR., El AL LIFTING SLING Filed May 10, 1932 3 Sheets-Sheet 3 IN VEN TOR Jra fluphfliy la WA TTORNEYS.

Patented Sept. 26, 1933 PATENT bFFIC E:

LIFTING SLING Lewis ML Showers, In, Juniata, and RalphL.

' I 'Stifile Altoona, Pal

I Application May/10, 1932. Serial No.610,44s

- 10 Claims. (C1. 294- 67) Ourinventionrelates to'lifting slings and more particularly to lifting slings which :are: adapted to'besuspendedfroman overhead hoisting apparatus, and which. are especially useful for 5 handling shipping' containers, such as=less-than-' carload-lot=containers, drop-bottom containers, demountable truck bodies or the like. Such containersare customarily accommodated: in spaced 1 relation in double .or'single rows onrthe floor of tates I a. hoistingiapparatus having provision for raising, lowering andfshifting ascontainer ina' able truck' bodies, and when the merchandise is unevenly distributed therein with the center of gravity of the load longitudinally distant from I the center of the container.

provideiin a'lifting sling, designed: forjuse with containers or the like, a pair of load carryingarms.

whichtiare'movable longitudinally to permit'th'e slingutobe'so' adjusted with respect tothe object. to be lifted that the center of gravity of the load will come longitudinally beneathi'the central suspension point of the sling, thereby preventing tilting of the object while itis suspended from thesling; I

in sucha lifting sling means for counter balancing-theweight of the movableload carrying arms so that when no load is carried'by the sling'it will be maintained in alevel 'positionirrespective designated at 5.

40 of the positions of the load carrying arms.

Our: invention is preferably further characterized by the provision of laterally extensible load carrying arms: adapted for adjustment to. accommodate containers of varying sizes; and by the provision of meansfor automatically locking the loadcarrying arms 'to the frame'of' the sling incident'to the raising of a load; and by other! sling 50f "ourzinvention, showing its aapplicatiomto afreightcar; To position them properly necessionto itsseat .orfraising a container from its seat Accordingly; one object of the inventiorr isto' Another object of the invention is .to provide.

Fig. I represents "a side' elevation of a lifting.

a truck bocly'container, thetop portion of which is indicated in diagrammatic outline beneath the sling.

Fig. II represents a top plan view of the sling.

by itself. 7 e

Fig. III represents an end elevation of the-- same. 7 V

Fig. IV represents a cross section of the same, taken as indicated by the lines IV--IV of Figs. I and II;

FigvV represents a cross section of the same, taken as indicated by the lines V-Vof Figs. I and II.

Fig. VI represents adetailed cross section of the end'portion of one ofthe load carrying arms,= ii= taken 'asindicated by the lines VIVI of Fig. II;

Fig. VII represents a detailed cross section of one of the trolleys upon which a load carrying arm is supported, taken as indicated by the lines I VII-VII of Fig. I. I r "s Fig; VIII represents a detailed cross'section of one of the counterweights, taken as indicated by the lines VIII-VIII of Figs. I and II.

Figs. IX and X represent enlarged detailed views of a load supporting wheeled carrier with portions thereof broken away for 'clearness of illustration", showing respectively the position of the yoke when no load is carried and the'position of the same when carrying a load; and,

"Fig. XI represents a modified or alternative form which the load carrying arms may take.

With particular reference to Figs. I, II and IV of the 1 drawings; there is shown an example of a lifting sling of our invention, in which the; framecomprises two channel beams 1rplaced" backto back and joined by plates Z-and 3 at the top and bottom; respectively, to form in effect: an I-beam the top flanges whereof are desige natedwat4-and' the bottom flanges whereof dare. Attachedv to the top of the frame at the center thereof, there is alifting eye 6 which is adapted to be suspended from a; hook 7 of an overhead hoisting apparatus.- The particular type of overhead hoisting apparatus to be used forms no part of our invention, .but"

it iscontemplated that the frame of the lifting slingwillbe freely suspended from the overhead. hoisting apparatus rather than rigidly attached? thereto. I I r y a Supported on the bottom. flanges 5' of the I-.beam frame, with 3 capacity for longitudinal movement thereon; thereare two wheeled car-g,

riersirorn 'whichload carryingv arms, compre hensively designated 8a and8b are suspended; I there being one such load carrying .arrnzizttr.eachp end of the frame. Each wheeled carrier comprises a pair of trolleys 9 on opposite sides of the frame joined together by a yoke 10 which straddles the bottom flanges 5; of the frame. Each trolley in turn comprises two wheels 11 and semi-elliptical leaf springs 12 curled at their ends to engage the axles 13 of the wheels and to form a span therebetween. As shown in Fig. VII, the wheels 11 are provided with ball bearings 14, and each'axle 13 is in the form of a bolt having a nut 15 thereon for maintaining the leaf springs, 12, the wheel 11, and the ball ample. clearance from the bottom fianges'5' of the I-beam frame, and on one of its inner vertical surfaces 22,-there is mounted a pair of swinging pawls 23. Each pawl 23 terminates in 3a tooth 24 which is adapted upon the flexing of the'springs 12 under load to engage a notched member or rack 25 disposed along the web of the I-beam frame, in the manner shown in Fig. X, wherein a portion of the yoke 10 is broken .away to showthe position of a pawl. There is one such rack 25 at one side of the frame extending from the center thereof to the end, and another such rack at the opposite side extendingwfrom, the center of the frame to, the

{other end. When no load is carried by the sling, j

the yoke 10 is raised by the springs 12 to the position shown in Fig. IX, in which case inclined surfaces 26 of, the yoke engage. lugs 2'7 on the swinging pawls, causing the pawls to be raised with the yoke and hence to be free from.

engagement with the rack 25.

From the above description it will be apparentv that the bottom fianges'5 of the channel beams 1 afford a track upon which the wheeled. carriers are independently movable lengthwise of the frame; and it will be further apparent that the wheeled carriers supporting the load carrying arms 8a, 8b are normally'unobstructed in their movement, but when a load is carried on thearms 8a,

8b, incident to theresulting downward flexure of the springs 12, the wheeled carriers are locked:

to the frame by the engagement of the fixed pawls 23 with the teeth ofthe rack 25. At the outer end of each rack 25,-there is provided'a block 30,

shown clearly in Figs. I and V, which serves as a stop limiting the travel'of the wheeled carrier. As a wheeled carrier approaches the .end of the frame, the ledge 31, shown clearly in Figs. I and IV, strikes the block 30 and prevents further movement.

At each end of the I'-beam frame there is a transverse plate 32. Adjacent to each plate 32 there are brackets 33 which afford a bearing for the shafts 35 of sheaves 36. The sheaves 36 are supported on ball bearings 37, as shown in Fig. V. 0n the top flanges 4 ofthe I-beam frame,- there are provided movable counterweights 38b and 38a for balancing the weightof the load carrying arms 8b,-and 8a, when a load is carried by the lifting sling in order to maintain the Sling At the base portion of each yoke' .-The yoke 10 is interiorly configured to provide in a level position irrespective of the positions of the load carrying arms. Each counterweight 38a, 38b may take the form shown in Fig. VIII in which the same comprises a rectangular block having depending ears 39 which serve as guides and recessed portions 40 in which rollers 41 are housed, the rollers 41 traveling on the top surface of the upper flanges 4 of the channel beams, and the ears 39 guiding the movement of the counterweight by engagement with the edges of the flanges 4. Each counterweight 38a, 38b is centrally slotted at 42 with the slot terminating in an inclined wall 43 so that the wings of the lifting eye 6 may enter the slot permitting the counterweight .to be movedinward from the ends of the frame to a point very near the center thereof.

Each counterweight 38a, 38b is also recessed at the top thereof, as indicated at 44, to provide a cavity which may be filled with lead or other material of the desired weight to effect the final balancing adjustment so that the frame will be in equilibrium with each counterweight 38a, 38b compensating forthe weight of the load carrying arm 8a, 8b at the opposite end of the frame.

The counterweight designated at 38b is connected by a wire cable 45b with the load carry-- ing arm 81), and similarly the counterweight 38a is connected by a wire cable 45a with the load carrying arm 8a. Thus'with reference to Fig. I, it will beseen that the wire cable 45b is attached as indicated at 46 to the top of the yoke 10 of the load carrying arm 8b. The cable 451) passes around a sheave-36 at the end of the frame shown at the right hand of the figure; then runs along the top of the frame through the counterweight 38a, passing freely through this counterweight; then runs through the counterweight 38b to which it is secured by a clamp 47 then passes around a sheave 36 at the opposite end of the frame; then passes through an eye 48 at the top of the yoke 10 of the load carrying arm 8a; and ultimately terminates ina turnbuckle-49 at the load carrying arm 8b. The other'cable 45a takes a similar course at the opposite side of the frame, connecting the loadpcarryingarm 8a with the counterweight 38a. Accordingly, 'it will be apparent that when no load is carried on the lifting sling, the load carrying arms 8a, 8b, irrespective of their positions, will be automatically balanced, and the sling thus maintained in equilibrium.

The load carrying arms 8a, 8b may take the form shown in Figs. I, II and III, in which case each arm comprises the pivoted connecting member 20, wire cables 50 terminating in hooks 51,

and an extensible spreader for varying the distance between the hooks 51. The spreader comprises interfitting tubular members 52 and 53 which are correspondingly internally and externally threaded. On the tubular member 52, hand wheels 54'are provided. By turning the hand wheels 54 in one direction, the tubular members 53 are' caused to be extended laterally; and by turning the handles 54 in the opposite direction, the tubular members 53 are contracted. The spreader terminates at each end in a head 55 grooved at 56 to receive the wire cable 50. Clamps 57 secure the cables to the spreader heads 55.

Alternatively the load carrying arms may take the form incomprehensively designated at 80 in Fig. XI. In this form a similar connecting mem-' ber 20 is employed for pivotal attachment to a wheeled carrier. Wire cables 58 leading from the connecting member 20 join the :endsof a spreader 59 and form therewith a triangle. The

. spreader 59 may be suitably made of seamless tubing with heads '60 of eiipanded formation. Each head '60 of the spreader 59 is slotted, as indicated at 61, and provided with three spaced notches 62 at-the slot 60.; Movable in the slot 60 atea'ch end of the spreader 59, there'is a link 63 which carries-ahook 64. In an obvious manner, the distance-between thetwo-hooks 64 of the load carrying arm 80 may be varied within limits by moving the links 63 from one notch 62 to another.

In Fig. I there is indicated diagrammatically at A, the top portion of a so-called demountable truck body having fixed attachments B near the viously described.

corners thereof engaged by the suspension hooks 51 of the load carrying arms 8a and 8b. With the truck body A disposed in relation to the lifting sling, as shown in Fig. I, the center line CL of the truck body is somewhat'remote longitudinally from the central suspension point of the I-beam frame, as indicated at :6. Assuming that the line CG represents a transverse plane through the center of gravity of the truck body A, the lifting sling would be positioned as shown in the drawings, with the load carrying arms 8a and 8b spaced unequally from the center of the I-be am frame so as to cause the central suspension point of the frame to come longitudinally above the center of gravity of the truck body. When the truck body is thus engaged, it may be raised without tilting and hence without danger of striking adjacent truck bodies or of jamming against guides on the vehicle platform from which it is raised.

From the above description it will be apparent that by employing load carrying arms such as shown at Ben and 8b, or at 80, which are independently movable, the lifting sling may be adapted for use with containers or truck bodies of varying sizes, and the load carrying arms may be so adjusted, by trial and error, as to permit a container to be suspended with the hook of the overhead hoisting apparatus longitudinally over the center of gravity of the container. When a container is thus engaged, and the lifting sling "is raised, the weight of the container causes the springs 12 of the trolleys 9 to flex downward which locks the load carrying arms 8a, 81) against longitudinal movement of the I -bea1n frame. After a container has been hoisted, shifted and lowered to a new position, and the lifting sling is disengaged therefrom, when the lifting sling is raised free of the load, it will be maintained in equilibrium by the action of the counterweights as pre- While we have described one example of the practice of our invention, showing, however, alternative arrangements for the load carrying arms, it will be apparent that various changes may be made in the form of the lifting sling herein described and illustrated without departing from the spirit of our invention as defined in the claims hereto annexed, and it will be further apparent that certain features of the invention may at times be used to advantage without a cor responding use of other features.

While in railroad parlance a distinction is made between containers and truck bodies, it is to beunderstood that the word containerias used in this application is used in its generic sense and is intended toinclude so-called truck bodies,

as well as other particular forms of containers. Having thus described our invention, we claim: 1. A lifting sling for hoisting rectangular containers comprising a frame adapted to be suspended at its center from an overhead hoist, load carrying arms movable independently on said frame; and means for counterbalancing 'each'saidarm whereby the frame is maintained in level position-when no load is carried thereon, irrespective of the positions of said arms.v

' 2. A lifting sling for lioistingrectangular containers comprising a frame adapted to be sus-- pended at its center from an overhead hoist, load carrying arms movable independently on said frame, and counterweights movable with said arms to maintain said frame in level position when no load is carried thereon, irrespective of the positions of said arms.

3. A lifting sling for rectangular containers, comprising a frame adapted to be suspended at its center from an overhead hoist, load carrying arms movable independently on said frame, a counterweight for each said arm disposed at the opposite end of the frame therefrom, and means connecting said counterweights with said arms whereby the counterweights are automatically movable with said arms to maintain said frame in level position when no load is carried thereon.

4. A lifting sling for rectangular containers comprising an I-beam frame adapted to be centrally suspended from an overhead hoist, laterally extending load carrying arms movable longitudinally on said frame, and counterweights for each said arm automatically movable to maintain said frame in level position when no load is carried thereon irrespective of the positions of said arms.

5. A lifting sling for rectangular containers comprising a frame adapted to be suspended from an overhead hoist, and load carrying arms movable longitudinally on said frame, said arms being normally unobstructed in their movement but being adapted to be locked to the frame by the weight of the load when a container is raised by said arms.

6. A lifting sling comprising a frame adapted to be suspended from an overhead hoist, and load carrying arms movable on said frame, said arms being normally spring supported with capacity for sliding movement on said frame but being adapted to be locked to the frame by the weight of the load when a load is raised thereby.

7. A lifting sling comprising a frame adapted to be suspended from an overhead hoist, said frame having a longitudinal track thereon and a notched member adjacent to said track, a carrier movable on said track, load carrying members on said carrier, and means whereby said carrier and load carrying members are normally unobstructed in their movement along said track but are adapted to be locked to said notched member by the weight of the load when a load is raised thereby.

8. A lifting sling comprising a frame adapted to be suspended from an overhead hoist, said frame having a track thereon and having a notched member adjacent to said track, a carrier movable on said track, load carrying arms suspended from said carrier, said carrier including nected by aleaf spring, a'load carrying arm supported on said spring, a notched member am'aof a load by said arms.

10. A lifting sling for containers of varying sizes comprising a frame adapted to be suspended from anoverhead hoist, and a load carryingarm movable longitudinally on said ,frame including interfitting tubular members extensible by rela-- tive rotation for adjusting. said arm to accommodate containers of varying widths.

LEWIS M. SHOWERS, JR. 7 RALPH L. STIFFLER;

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