US1733236A - Lifting tongs - Google Patents

Description

1.. G. PEARCE LIFTING Tones Filed Feb. i4, 192s Patented Oict.

UNITED STATES PATENT OFFICE LIFTING TONGS Application filed February 14, 1929. Serial No. 339,864.

My invention relates to lifting tongs and is hereinafter described more particularly in connection with the handling of metal bars, but it will be understood that the device is capable of use in lifting and transporting various other materials.

One of the objects of my invention is to eliminate the dangerous and laborious task of placing slings around hot bars by providing a series of arms which will automatically encircle the bars, enabling them to be lifted by a crane. The mechanism embodied in my invention is so arranged that the whole operation of placing the device over the bars,

closing the arms7 carrying the bars to the desired location, and depositing them there by opening the arms, can be performed entirely by the man operating the crane which carries this device, thereby eliminating the necessity of a man approaching the hot bars.

Another object of my invention is to simplify and improve generally the structure and operation of lifting tong devices.

The invention described herein relates to a device consisting principally of a spreader beam from which are suspended one pair or a series of pairs of carrier arms or tongs, each pair of arms being hinged on a common pin or shaft and opposed to .each other, and a 3o;mechanism to automatically open and close these arms. The device is so arranged that it may be carried by means of a crane and laid with the arms in the open position over a number of bars and the arms closed to com- 'pletely encircle the bars and to permit of their being carried to another location where the arms are openedthus depositing the bars.

Itis common practice in steel mills to carry steel bars by a crane using a magnet or chain slings placed around the bars, but'it is often necessary to carry hot steel bars, as, for instance, when it is desired to place them in an annealing pit to cool slowly and owing to the non-magnetic characteristics of steel above a certain temperature it is impossible to lift them with a magnet, which makes it necessary to place chain slings around the hot bars in order to lift them.

Some of the forms which my invention may take are shown in the accompanying drawing wherein Figure 1 is a view of the apparatus, partially in side elevation and partially in section; Fig. 2 is an end elevational view of the structure of Fig. 1 with the tongs in open position; Fig. 3 is a view similar to F 2, but showing the tongs in closed position; Fig. 4 is a view taken on the line lV-IV of Fig. 1; Fig. 5 is a View showing the manner in which the guide bars are mounted; Fig. 6 shows views of one of the lifting hooks and of one of the stop collars with which it is associated; Fig. 7'shows views of one of the guide bars and of a stop collar that has co-operative relation thereto, and Fig. 8 is a view similar to Fig. 2,' but showing a modification thereof.

As shown in Figs. 1 to 7, the apparatus comprises a spreader beam 10 which may have a suitable connection with a traveling crane (not shown) in any manner wellknown in the art. The load is transmitted to the spreader beam through hangers 11 in whose lower ends a hook-supporting or rock shaft- 12 is mounted for oscillatory movement.

Hooks 13 are loosely supported on the shaft 12 and have limited rotative movement thereon, the rotation being limited by means of the end walls of a recess 14 which come into contact with the lug of a stop collar 16 that isA rigidly secured to the shaft 12, so that when the shaft 12 is in a given rotative position, the hook 13 may swing freely to and from the positions shown in Figs. 2, 3 and 4., as hereinafter explained.

Tongs 17 are arranged in pairs and are pivotally mounted upon a hinge shaft 18. The tongs 17 have extended portions 19 that are engaged by links 20 whose upper ends have pivotal connection with a pin 21 with one of the hangers 11. The pivot pin 21 eX- tends through a slide block 22 that has vertical movement in a slot or slideway 23 of the hanger l1.

It will be seen that with the parts occupying the positions shown in Fig. 2, the tongs 17 will be supported through the links 20, the pin 21, the block 22, and the hanger 11, with the result that such hooks are held in spread-apart relation. In'this position, the tongs are ready to engage bars which are indicated at 24, for the purpose of transporting them. The bars 24 are shown as mounted on skid rails 25 such as are ordinarily provided in steel mills for supporting metal bars or ingots and which are spaced apart to 'permit the tongs 17 to pass between them, as shown in Fig. 2. A The tongs 17 at their upper or horizontal portions may rest directly upon the bars, but I have shown them as supported by separator sleeves 26 which rest directly upon the skid rails and which are supported upon rods 27 that extend through the tongs.

The-sleeves 26 may be dispensed with, if desired, but they serve to hold the tongs in properly spaced relation longitudinally' of the "rods: 27, and are removable to permit gfyusubstitution of sleeves of other lengths, to vary the spacing between the tongs at eich side 'ofthe tong structure and to thus adapt it for handling bars of various lengths. rEhe bars 27' serve the further function of insuring ftliat the tongs will move in unison.

The tongs being supported from the pins 21,V asshown in Fig. 2, they are of course spread-apart relation as above-explained. After they have been lowered into bar-engag- Bolling position, asin Fig. 2, further lowerirg movement of the spreader 10 will be pe mitted, by reason of the slidable engaor-,inent between the blocks 22 and the hang s 11. This further downward movement results i1 lowering of the hinge shaft 12 and the hooks 13 carried thereby, until the inclined faces ofthe hooks engage the hinge shaft 1, thas causing them to be pushed to one side and to then pass beneath the hinge shaft 18 as 40'shown'in Fig. 3.y Y

If the beam 1G be now elevated, trie hangers 11 will 'carry withv them the .hook suppe shaft 12"'and the hook 13 will in ti n litt the hinge shaft 18, the tongs 17 swinging,-through the actionzof gravity, into the position shown in Fig. '3, thus closing about the bars 24.

-VVhenthe bars 24 have been transportl to'their'destination, the spreader 1r=eam 10 is lowered until the'bars 24 are brought to rest 56fu`pon a supporting surface, to thereby relieve the hinge shaft 18 of the weight of the tongs andthe bars, and permitting the beam l() to to 'belowered to such position that the hooks 13";can be swung clear of the shaft 18.

Thereupon, the shaft 12 is rocked by means of a crank 29 which may be operated by the cranemenll The crank 29 is rigidly secured to the" shaft 12 and the-shaft also has rigidly secured thereto the stop collars 16 which, as 60"above-explained, have lugs 15 that entend into: recesses 14 of the hooks, so that when the V bb'elevated," theshaft 12 will be raised to the' position shown in Fig. 2 and the tongs 17 will be spread apart, through taking up of the lost motion between the blocks 22 and the hangers 11.

ln order to maintain the beam 10, the hook .0 shaft 12, and the hinge shaft 18 in verticallyalined relation, and thus prevent the moving partsof the structure from becoming disarranged relative to one another and to insure their smooth operation, l provide guiding bars 31 which have slidable connection with the beam 10 at their upper ends, and whose lower ends are supported on the shaft 18. The shaft 12 entends through blocks 32 that are slidably mounted in slideways or 5g slots in the bars 31, so that while the hinge shaft 12 may have the necessary vertical movement to permit the hooks 13 to be moved into and out of engagement with the shaft 18, the shaft 12 will nevertheless be heldin 85 proper vertical alinement between the shaffU 18 and the beam 10.

ln orner to limit rotative movement ofthe shaft 12 when it is rocked by the crankY 29, l secure one or more stop collars 3st thereto 9c which are cut out as shown in Fig. 7, and into which'cut-out portions, lugs 35 of hangers 11 extend, the length of the cut-out portion depending upon tlie arc through which it is desired to rotate the sli'aft12. Y 95 Referring now to Fig. 8, l show a structure wherein each hook 17L and its eznendedV portions 19lnt are disposed at diametrically opposite sides of the shaft- 18. Links it) are connected to the extensionsv 19? and are slid-V ably supported from the hanger beam 10 .as ai'e the links 28 of Fig. 2.

lt will be seen, iowever, that in this'arrangement, the hooks 17 n are closed through elevation of the spreader beam 10 instead of being'thereby forciblyopened, and that the hook 13 is utilized to hold the tongs 17L1 open, or spread apart, such hook engaging with a pin ell which has connection withHthe tongs through links 42.

In this latter arrangement, whenit isfdesired to engage a bar or bars for the purpose of transport-ing them, the tongs are brought into operative position with respect tothe bars whereupon the hook 13 is'swung out'of' latching position so that upon upward movement ofthe beam 10, the tongs will be closed and the material lifted.

In thefhandling of shorter bars, I- may utilize auxiliary or intermediate tongs l5 as 12u shown in Fig. 1. These tongs 45 areipivotally and slidably supported from the shaft'18 and are movable in unison with the tongs 17 by means of the connected rods 27 that entend through all of the tong arms on `each side of the structure. y

I claim as my invention v1. Lifting tongstructure i comprising beam, a hook-supporting shaft connectedY to said beam, hinge shaft-,tongs pivotally E3 mounted on said hinge shaft, a hook carried by the first-named shaft and movable into and out of engaging position with the hinge shaft, a vertically-disposed guide member for maintaining said beam and said shafts in vertical alinement, and a lost-motion connection between the hinge shaft and the beam for permitting movement of the beam and the hinge shaft relative to one another in a direction longitudinally of said guide member.

2. Lifting tong structure comprising a beam, a hook supporting shaft connected to said beam, a hinge shaft, tongs mounted on said hinge shaft, a hook carried by the first- 0 named shaft and movable into and out of engaging position with the hinge shaft, a guide member for maintaining said beam and said shafts in vertical alinement, and means providing lost motion connection in a vertical direction between the tongs and the said beam.

3. Tong structure comprising a plurality of pairs of tongs mounted upon a hinge shaft for opening and closing movement and slidably supported thereon, and means Carried u. by the tong members at one side of said shaft for causing unitary movement thereof and permitting adjustment of the tong members longitudinally of said shaft.

t. rlong structure comprising a beam, a hook supporting shaft disposed beneath the beam, a hinge shaft disposed beneath the hook-supporting shaft, the said beam end shafts being disposed in parallelism, tongs carried by the hinge shaft, a hanger connecting the hook supporting shaft t-o the beam,

a lost motion connection betweenv'the beam and the tongs, and a hook carried by the hooksupporting shaft in position to engage the hinge shaft when the said shafts are in proximity to one another.

5. Tong structure comprising a beam, a hook-supporting shaft ydisposed beneath said beam, a hinge shaft disposed beneath the hook-supporting shaft, the said shafts and beam being in parallelism, means connecting the hook-supporting shaft and the beam, pairs of tongs carried by the hinge shaft, and having link connection with the beam, and a hook carried by the hook-supporting shaft in position to engage the hinge shaft when said shafts are moved into proximity to one another.

6. Tong structure comprising a beam, a hook-supporting shaft disposed beneath said beam, a hinge shaft disposed beneath the hook-supporting shaft, the said shafts and beam being in parallelism, means connecting the hook-supporting shaft and the beam, pairs of tongs carried by the hinge shaft and having link connection with the beam, and a plurality of hooks carried by the hook-supporting shaft at points spaced longitudinali thereof in position to engage the hinge sha t when said shafts are brought into proximity to one another.

7. Tong structure comprising a beam, a hook-supporting shaft disposed beneath said beam, a hinge shaft disposed beneath the hook-supporting shaft, the said shafts and beam being in parallelism, means connecting the hook-supporting shaft and the beam, pairs of tongs carried by the hinge shaft and having link connection with the beam, a plurality of hooks carried by the hook-supporting shaft at points spaced longitudinally thereof in position to engage the hinge shaft when said shafts are brought into proximity to one another, means for oscillating the hook-supporting shaft, and lost mot-ion connection between said shaft and the hooks.

8. Tong structure comprising a beam, a hook-supporting shaft carried thereby, a hinge shaft, tongs pivotally mounted on said shaft intermediate their ends, a link carried by the upper end of each of the tong members, a lost motion connection between said links and the beam, and a hook carried by the hooksupporting shaft in position to engage the hinge shaft when said shafts are brought into proximity to one another.

9. Tong structure comprising a beam, a hook-supporting shaft carried thereby, a hinge shaft, tongs pivotally mounted on said shaft intermediate their ends, a link carried by the upper end of each of the tong members, a lost motion Connection between said links and the beam, a hook carried by the hooksupporting shaft in position to engage the hinge shaft when said shafts are brought into proximity to one another, other tongs pivotally mounted on the hinge shaft, and connections between the first-named tongs and the second-named tongs to effect unitary movement thereof.

In testimony whereof I, the said LEONARD G. PEARCE have hereunto set my hand.

LEONARD G. PEARCE.

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