US2790672A - Attachment for lifting tongs - Google Patents

Description

April 30, 1.957 J. w., PICK ET AL 2,790,672

ATTACHMENT FOR LIF'TING TONGS Filed oct. ze, 195s I lim-ll' 54, i. ng, L g; ...mmummlml fz; F?

Unid Sme Para '0 ATTACHMENT FOR LIFTING TONGS Joseph W. Pick, Middletown, Otto E. Martin,Hamlton, and Earl P. Gividen and Richard L. Frye, Middletown, Ohio, assignors to Armco Steel Corporation, Middletown, Ohio, a corporation of Ohio Application October 26, 1953, Serial No. 388,167

4r Claims. (01294-406) This inventionrelates to an improvement in lifting tongs of the type commonly used in steel mills for lifting coils and the like. Such lifting tongs generally have a pair of shoe-bearing, load-grappling arms carried `'by a toggle. .When the toggle is lifted, the shoes move toward each other to grip and lift the loa'd and when the load is disposed, the shoes spread apart to release it. Lifting tongs of the type under consideration are disclosed in the Heppenstall patent, No. 2,536,932, dated January 2, 1951.

By virtue of the design of lifting tongs such as outlined above, it is a characteristic of such tongs that their gripping eiiciency decreases as the gripping jaws approach each other. Thus, in the handling of coils of steel if the coils are relatively thick, the tongs grip them rmly and handle them eiciently. However, when thin walled coils are involved (and by thin walled coils we mean coils having a wall thickness less than about 8), considerable trouble is had in that the tongs fail to grip the coil tightly and the coil slips out. This is particularly true if the crane operator raises the tongs too fast or if the coils have been oiled.

With the foregoing considerations in mind, it is an object of the present invention to provide an improvement in lifting tongs `by means of which thin walled coils or other relatively thin loadsrequiring a bite of less than about 8 may be handled as efficiently as loads requiring a larger bite.

it is another object of the invention to provide such an improvement which will not interfere with the use of the tongs in the conventional manner. It is still another object of the invention to provide Such a device which can readily -be installed on existing tongs for the purpose described.

These and other objects of the invention which we shall discuss in more detail hereinafter or which will 'become apparent to those skilled in the art, upon reading these specifications, we accomplish by that construction and arrangement of parts of which we shall now describe an exemplary embodiment.

Reference is made to the drawing forming a part hereof and in which:

Figure 1 is a fragmentary elevational view of lifting tongs in position to engage a coil of steel or the like, showing our improvement in non-operating position.

Figure 2 is a fragmentary cross. sectional View taken on the line 2-2 of Figure l.

Figure 3 is a fragmentary view similar to Figure 1 showing our device in its operative position for use with a thin walled coil.

Figure 4 is a fragmentary cross sectional view taken on the line 4 4 of Figure 3.

Figure 5 is a perspective View of one of the hinge blocks, and

Figure 6 is a perspective view of one of the hinge links.

Briefly, in the practice of our invention we provide a pair of filler blocks pivotally mounted on hinge links which hinge links are hinged adjacent yopposed edges of the gripping shoe on one of the arms of the tongs. The gripping shoes may be positioned over the gripping face of the gripping shoe or they may be swung aside into inoperative position. A pair of tension springs hold the hinge blocks yieldingly in one position or the other.

The details of construction and operation of the tongs form no part of the present invention and for an understanding thereof, reference is made to the said Heppenstall patent.

For purposes of the present disclosure, it is necessary to point out only that the tongs comprise a pair of shoebearing, load-grappling arms indicated generally at 10 and 11. The arm 10 is provided with the shoe 12 and the arm 11 is provided with the shoe 13. The tongs which are generally designated by the character T are suspended from a crane by means of an element 14 and it will be understood that as the element 14 is raised, the arms 10 and 11 and therefore the shoes 12 and 13 are caused to approach each other to grip a load positioned therebetween. As a load, we have shown in these drawings a coil of steel C.

The tongs function in conventional manner, as long as the coil C is 8" or more in thickness, without the use of 4our improvement as shown in Figures l and 2. Where. however, the coil is a thin walled coil, less than about 8" in wall thickness, as indicated at C in Figures 3 and 4, the device of our invention becomes necessary.

We provide a pair of filler blocks 15, best seen in perspective in Figure 5. These filler blocks are provided with the pintles 16 'by means of which they may be pivotally or hingedly mounted and with an attaching element 17 to which a spring may be attached.

The hinged blocks 15 are mounted on the arm 11 by means of the hinge links 18, best seen in perspective in Figure 6. The links 18 have the pintles 19 and 20 and they are also provided with a stop abutment 21. Pintle brackets 22 are secured by welding or in other suitable manner to the arm 11 behind the shoe 13. The hinge links 18, of which we have shown two on each side, are then hinged by means of pins 23 passing through the pintle brackets 22 andthe pintles 19.

The blocks 15 are then pivotally mounted on the three ends -of the hinge links 18 -by means of pins 24 which pass through the pintles 16 and 2t).

A back stop member 25 is provided on the arm 11 to limit the rearward movement of the links 18, as best `seen in Figure 2, and it will be clear that the abutments 21 limit the outward swinging 4movement of the filler blocks 15.

Springs 26 connect the securing elements 17 with the securing elements 17a on the arm 11 and from a consideration of Figures 2 and 4 it will be observed that in the movement of the blocks 15 from the inoperative position of Figure 2 to the operative position `of Figure 4, the axes of the springs 26 cross over the axes of the hinge pins 23. It will also be observed that the axes of the springs 26 are at all times inside the axes of the hinge pins 24.

The operation of the device will be clear from what has been said above. lf normal coils, having a wall thickness of about S or more, are being handled, the blocks 15 are moved to the position of Figure 2 and the tongs operate in conventional manner. When, however, a relatively thin load, such as a thin walled coil C', requiring a bite of less than about 8 is to be handled, the blocks 15 are swung into the position of Figure 4 whereby the size of the bite is effectively reduced without causing the gripping arms of the tongs to approach each other unduly.

It will be clear that numerous modifications may be made without departing from the spirit of this invention s modera and we, therefore do not intend to limit ourselves except as set forth in the claims which follow.

opposed vertical edges of said shoe, ailler block pivotally secured to the treeendsptthe resptivehinse links., and

Having now fully described our invention, what u n claim as new and desire to secure by Letters Patent is:

1. In combination with lifting tongs of the type having a pair of shoe-bearing, load-grappling arms carried by a toggle, such that when the toggle is lifted the shoes move toward each other to grip and lift a load, and when the load is deposited the shoes spread apart to release it; hinge links pivotally secured to one of said shoes adjacent opposed edges of sai-d shoe, a ller block pivotally secured to the free ends of the respective hinge links, and tension springs secured at one end to the respective ller blocks adjacent the free end of said blocks, and at their other ends to the arm carrying said shoe, the axes of said springs in, one position of said blocks passing inside the first mentioned pivots, and in the other position outside the first mentioned pivots to hold said blocks yieldingly in one position or the other,

`2. In combination with lifting tongs of the type having a pair of shoe-bearing, load-grappling arms carried yby a toggle, such that when the toggle is lifted the shoes move toward each other to grip and lift a load, and when the load is deposited the shoes spread apart to release it; hinge links pivotally secured to one of said shoes adjacent tension springs secured at one end to the respective filler blocks adjacent the free end of said blocks, and at their other ends to the arm carrying said shoe, the axes of said springs in one position of said blocks passing inside the rst mentioned pivots, and in the other position outside the first mentioned pivots to hold said 'blocks yieldingly in one position or the other.

3. The structure of claim 1, wherein stops are provided on said hinge links to limit the outward hinging movement of said ller blocks with respect to said hinge links.

4. The structure of claim 1, wherein stops are provided to limit the outward hinging movement of said hinge links and wherein'stops are provided on said hinge links to iimit the outward hinging movement of said ller blocks with respect to said hinge links.

References Cited in the lc of this patent UNITED STATES PATENTS 2,536,932 Heppenstall Jan. 2, 1951 2,610,890 Jaeger Sept. 16, 1952 2,670,985 King May 2, 1954

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