US3029100A - Lifting tongs - Google Patents

Description

E. A. LAINE LIFTING TONGS April 10, 1962 3 Sheets-Sheet 1 Filed May 16, 1960 E. A. LAlNE LIFTING TONGS April 10, 1962 3 Sheets-Sheet 2 Filed May 16, 1960 c alll rf'flv 2 United States Patent 3,029,100 LIFTING TONGS Edward A. Laine, Leechburg, Pa., assignor to Allegheny Ludlurn Steel Corporation, Brackenridge, Pa., a corporation of Pennsylvania Filed May 16, 1960, Ser. No. 29,400 4 Claims. (Cl. 294-106) This invention relates to lifting tongs, and in particular to lifting tongs of the type for engaging, lifting and transporting coils of steel strip.

Tongs of this type and which utilize a pair of loadgrappling, shoe-bearing arms carried by a toggle or the like have been known heretofore, being designed so that when the toggle is lifted, the shoes move towards each other to grip and lift the load, and when. the load is deposited, the shoes spread apart to release the load. The prior art tongs, however, have had a number of disadvantages in that structural weaknesses often develop so that the load is gripped imperfectly. Generally such tongs designed for lifting coils which may be of different diameter are provided with only one pair of opposed shoes for gripping only one side of the coil, thus creating an unbalanced load condition in the tong apparatus and often causing considerable damage to the coil being transported which is gripped on only one side of the coil, whereby sagging of the unsupported side is permitted. Difiiculty has also be encountered with the prior art tongs in applying equal force to the gripping shoes so as to obtain substantially equal pressure on the coil in the gripping Zone.

An object of this invention is to provide a lifting tong having two pairs of opposed shoes operable for gripping diametrically opposite sides of a coil with substantially equal pressure applied simultaneously thereto.

Another object of this invention is to provide lifting tongs having two pairs of opposed shoes for gripping opposite sides of a coil and to include in the construction a linkage mechanism for effecting equal movement of the corresponding shoes of each pair to thereby equalize the1 gripping force applied to the opposite sides of the cor A further object of this invention is to provide lifting tongs having two pairs of opposed shoes for gripping opposite sides of a coil and to include in the construc tion a linkage mechanism for initiating and simultaneously effecting the movement of one shoe of each pair to seat against the inside surface of the coil prior to effecting movement of the other shoe of each pair to simultaneously seat against the outer surface of the coil and to apply gripping pressure thereto.

Other objects of this invention will become apparent from the following description when taken in conjunction with the accompanying drawing in which:

FIGURE 1 is a view in side elevation and partly in section of the tongs showing the gripping shoes in a spread or open position;

FIG. 2 is a view in section of the tongs taken along the line II-II of FIG. 1;

FIG. 3 is a top plan view of the tongs of FIG. 1;

FIG. 4 is a view in side elevation and partly in section of the tongs of FIG. 1 showing the gripping shoes in a closed, grappling position;

FIG. 5 is a view in section of a portion of the gripping shoe mountings taken along the line V-V of FIG. 1, and

FIGS. 6, 7, 8, 9, l0 and 11 are views in section taken along lines VI-VI, VII-VII, VIII-VIII, IX-XI, X-X and XI-XI, respectively, of FIG. 1.

Referring to the drawings, the tongs illustrated are formed particularly for gripping and transporting coils of steel strip such as the coil 10, the coil gripping members being two pairs of opposed shoes 12-14 and 16-18 3,029,109 Patented Apr. 10, 1962 disposed to grip diametrically opposite side wall portions of the coil. In this embodiment a frame member 20 is utilized to support the linkage mechanism (to be described hereinafter) which actuates and supports the opposed gripping shoes. The frame member is of a substantially rectangular shape having a pair of spaced opposite side walls 22 connected by spaced opposite end walls 24.

The corresponding external shoes 12 and 18 and the corresponding internal shoes 14 and 16 of the pairs of shoes are pivotally carried on similar grappling arms which extend below the lower edge of the supporting frame member 20. Thus shoes 12 and 18 are carried at the lower end of spaced grappling arms 26 and 28, respectively, which are disposed in opposite relation to one another whereas shoes 14 and 16 are carried at the lower end of spaced grappling arms 39 and 32, respectively, which are also disposed in opposite relation to one another. Each of the grappling arms 26 and 28 is in the form of a bell crank lever, the lower end of which extends below the frame 20 for receiving the shoes 12 and 18, respectively. The shoes 12 and 18 have their coil contacting faces curved to substantially the outside curvature of the coil surface that is to be engaged and have a pair of spaced flange members 34 and 36, respectively, only one of each of which is illustrated, extending from the back of the shoe in spaced relation to fit closely adjacent to the opposite sides of the lower end of grappling arms 25 and 28 and being pivotally mounted thereon as by means of bearing pins 38 and 40, respectively.

The grappling arms 30 and 32 on the other hand are each formed of a pair of spaced longitudinally extending levers 42-44 and 46-43 (see FIGS. 1, 2, 3, 6 and 9) pivotally mounted as by pins 5i and 52, respectively, which are supported in the side walls 22 of the frame 26. The grappling arms 30 and 32 also have their lower ends disposed to extend below the frame 2!} to receive the shoes 14 and 16, respectively. In this instance the shoes have their contacting faces formed with a curvature corresponding to the curvature of the inside surface of the coil that is to be gripped, whereas the back of the shoes 14 and 16 is provided with outwardly extending spaced flanges 54-56 and 58-60, respectively, disposed to fit in between and closely adjacent to the lower ends of the levers 42-44 and 46-48, respectively, and to be pivotally secured thereto as by means of pins 62 and 64, respectively, spacer members 65 and 68, respectively, being disposed about such pins between the fianges of the shoes. As illustrated in FIGS. 1 and 4, the lower surface of the gripping arms 30 and 32 is each provided with a cam lobe seat 70 and 72, respectively, and a cam ramp '74 and 76, respectively, each of the cam ramps having a curved surface having a predetermined radius, the purpose of which will be explained more fully hereinafter.

Movement of the shoe-carrying arms 26-28 and 30-32 is controlled by operation of a toggle 78 which has pairs of upper and lower links 80-82 and 84-86, respectively, the upper links being hung at their upper ends as by pins 88 and 90, respectively, to a supporting bar 92 which is connected as by a pin 94 to a bail or clevis 96 by which the tongs are lifted. In this embodiment, each pair of upper and lower toggle links includes spaced front and rear members, these being upper links 98-100 and 10 104 and lower links 106-108 and 110-112, the upper and lower links being pivotally connected as by pins 114 and 116 (see FIGS. 8 and 11) which carry suitable spacer members and 117, respectively. The lower links 84 and 86 are pivotally connected to and supported on the frame 20 as by pins 118 and 120, respectively, spacer members 122 and 124 being disposed between the spaced lower links 106-108 and 110-112, respectively, about such pins.

In order to effect predetermined movement of the arms 31 and 32 to actuate the shoes 14 and 16 into engagement with the inner surface of the coil 16, each of the links 166-468 and 116-112 of such arms is provided with a cam 126-123 and 136-132, respectively, on the external surface of such links, such cams being disposed with their lobes to engage and seat in the cam lobe seats '72 and 76, respectively, of the arms 32 and 30, respectively, when the toggle '78 is in the collapsed position illustrated in FIG. 1 and to bias such arms 32 and 311 about their respective pivots 52 and 50 as the toggle 78 is raised towards the position illustrated in FIG. 4' with the end of the cams 126-128 and 130-132 riding on the cam ramps 76 and 74, respectively, of the arms 32 and 31), respectively, Without efiecting further movement thereof. The cam ramps are provided with such radii that arms .30 and 32 are locked into a stationary position after their initial movement and cannot be displaced by forces of external shoes 12 and 18.

The arms 84 and 86 are connected at their lower ends as by means of pins 134 and 136, respectively, to support and actuate outer grappling arms 28 and 26, respectively, such arms being provided with elongated openings 138 and 146, respectively, positioned angularly therein extending lengthwise of the arc of movement of the pins 134 and 136 toprovide in effect a predetermined amount of lost motion between such pins and the grappling arms before pivotal movement of the lower links 84 and 86 about their respective pivot pins 118 and 120 will effect any movement of the grappling arms 28 and 26, respectively. This predetermined lost motion is designed to permit a positive operation of the grappling arms 32 and 36 through the action of the cam lugs to force the shoes 16 and 14, respectively, into engagement with the surface of the inside diameter of the coil before any movement of the outer shoes 18 and 12 is initiated by a raising of the toggle 73. As illustrated in FIG. 6, the gappling arm 28 is mounted in assembled relation to links 166-188 and is spaced therefrom by spacer member 135 about the pin 134.

As illustrated, the bell crank grappling arm 26 has an end thereof connected as by pin 142 to the lower end pair of links 144-146 which are also pivotally mounted on pin 56 and the bell crank grappling arm 28 has an end thereof connected as by pin 14 8 to an end of a pair of links 150-152 which are pivotally mounted on pin 52, the links 150-152 and the grappling arm links being spaced by spacers 153 as pivotally mounted on pin 52 (see FIG. 7). The other ends of links 144-4 16 and 150-152 are connected (see FIG. 10) as by pins 154 and 156, respectively, to a connecting link 158. The grappling arms 26 and 28 are thus supported from the pins 50 and 52 in cooperation with the pins 136 and 134, respectively, and are so connected as by the link 158 that simultaneous movement of the arms and consequently shoes 12 and 18 will be eifected as the arms are moved, to thereby effect an equalizing of the pressure applied through each of such shoes. A pin 160 is carried by the frame and extends between the side walls 22 thereof, being disposed as a stop between the lower ends of grappling arms 36 and 32 to limit movement thereof towards the open position so as to insure that both shoes 14 and 16 will move equal distances from the coil.

Where it is desired to provide the use of a latching mechanism to hold the grappling arms in their open position so that the tongs can be readily positioned on a coil or to free the coil, a latching mechanism 162, illustrated in dot-dash outline in FIG. 1, is mounted on one of the links of arm 86 for cooperating with a keeper member 164 that is carried at the end of the frame 26. The latching mechanism comprises a sleeve 166 carrying a vertically reciprocable and rotatable plunger 1168 provided with an enlarged head portion. The latching mechanism is preferably of a type clearly disclosed in Patent No. 1,839,389 and is designed so that when the plunger enters the keeper member 164, certain cams (not shown) formed interior-1y of sleeve 166, effect a rotation of the plunger which locks the members together. In this posh tion, the tongs can be lifted clear of a coil and be moved into position to pick up another coil. As the tongs are positioned to seat on the coil to be picked up, the plunger 163 is again rotated so as to permit it to withdraw from the keeper when the tongs are again lifted.

In practice, the coils of steel strip material which are to be conveyed are usually wound on substantially standard rnandrels so as to have a substantially constant internal diameter which is in the neighborhood of 19 to 20 inches. This is a fact regardless of the thickness of the coil which may range from 10' inches up to 15 inches wall thickness. The tongs of this invention are designed for use with such a substantially constant internal diameter coil, the grappling arms 31) and 32 being designed so that the shoes 14 and 16 carried thereby clear and fit within the internal diameter when the tongs are in the open position so that the tongs can be lowered in a grappling position over the coil with the shoes 16 and 16 within the confines of the internal diameter of the coil disposed to engage the internal surface of the coil.

In operation, the tongs are positioned over the coil with the grappling arms in the position illustrated in FIG. 1. When thus positioned, the latching mechanism 162 is released, as described hereinbefore, and with tie latching mechanism so released, the toggle 78 is raised as by means of a suitable lifting hook (not shown) engaging the bail 96 to spread the pantograph formed by the upper links 31) and 82 and the lower links 34 and 86 of the toggle 73. As links 84' and 86 are pivoted about their pivotal pins 118 and 120, respectively, the cams 126-128 and 130- 132, respectively, are actuated about the pivots 118 and 120, respectively, to engage the cam lobes 72 and 79, respectively, against the cam ramps '74 and 76 of the grap pling arms 32 and 36, respectively, to form such grappling arms about their pivot pins 52 and 56, respectively, to drive the shoes 16 and 14, respectively, into contact engagement with the internal surface of the coil 16. Continued upper movement of the toggle 78 has no further effect on the grappling arms 32 and 31) since the surface of cams 126-128 and 136-132 engages and rides on the predetermined radii of cam ramps 76 and 74 of the grappling arms 32 and 36, respectively, such continued movement of the cams 126-128 and 130-132 to the position illustrated in FIG. 4 merely serving to maintain the shoes 16 and 14 in positive engagement with the internal surface of the coil 10.

It is to be noted that the initial movement of the lower links 84 and 86 of the toggle 78 about the pivot pins 113 and 126, respectively, effects a positive drive of the internal shoes 16 and 14, respectively, into engagement with the internal surfaces of the coil 11 Such initial movement of the shoes 16 and 14 and of the links 84 and 86 has no effect on the grappling arms 28 and 26, respectively, since the pins 134 and 136, respectively, carried at the end of the links 84 and 86, respectively, slide in the slots 138 and 140, respectively, contained in the grappling arms 28 and 26, respectively. The slots 138 and are of predetermined length so that sufiicient movement of the cams 126-128 and 130-132, respectively, can be obtained to force the shoes 16 and 14, respectively, into engagement with the internal surfaces of the coil 10 before any movement of grappling arms 28 and 26 will be effected. Continued movement of the toggle in an upward direction after the shoes 16 and 14 have been actuated as described will cause the pins 134 and 136 to slide in the slots 138 and 140 of the grappling arms 23 and 26 to the point where the pins 134 and 136 engage the lower portion of such slots to thereby drive the grappling arms 28 and 26 in a direction toward the outer surfaces of the coil 10, it being noted that such driving force applied to the outer grappling arms effectively drives the grappling arms 28 and 26 inwardly towards the coil 10 effecting a movement of the links 150 and 144, respectively, about the pivot pins 52 and 50, respectively, the links 150 and 144 being integrally connected as by the connecting link 158. Because of the connecting linkage between the ends of the grappling arms 28 and 26, simultaneous movement thereof is obtained and, when the shoes 18 and 12 engage the outer surfaces of coil 10, substantially equal pressure is applied thereby to the outer surface of the coil, it being noted that when thus applied, each pair of shoes 12-14 and 16--18 has the shoe members thereof in alignment with each pair being applied diametrically opposite one another to the inner and outer surfaces of the coil. It will be appreciated, that with the coil gripped in this manner, the coil is firmly supported and will not sag when transported by the tongs. By gripping the coil first by the inner shoes 14 and 16 and later by the outer shoes 12 and 18, it will be appreciated that movement of the coil during the gripping action is prevented since the coil is centered with respect to the tongs through the action of the inner shoes 14 and 16 engaging the inner surfaces of the coil prior to effecting the engagement of the outer shoes 12 and 18 with the outer surfaces.

After the coil has been transported to the location where it is to be placed, the lifting; force on the toggle 78 is released so that the toggle 78 tends to collapse of its own weight with the result that thelo-wer links 84 and 86 pivot about their pivot pins 118 and 120, respectively, to drive the pins 134 and 136, respectively, away from the lower ends of the Slots 138 and 140, respectively, contained in the grappling arms 28 and 26,, respectively, so as to release the pressure on the shoes 18 and 12, respectively. As the pins 134 and 136 move in the slots 138 and 140, respectively, they. finally engage the opposite ends of such slots to apply a positive force to the grappling arms 28 and 26, respectively, to drive such grappling arms in a direction to release the shoes 18 and 12, respectively, from engagement with the outer surfaces of the coil 10. The continued collapse of the toggle 78 effects movement of the cams 126128. and 130-432 along the surfaces 76 and 74, respectively, until the lobes thereof slide into the cam lobe seats 72 and 70, respectively, causing movement of grappling arms 32 and 30 to permit movement of such grappling arms about their fixed pivot pins 52 and respectively, to drive the shoes 16 and 14, respectively, away from their contact engagement with the internal surface of the coil. Of course, when the toggle 78 is collapsed as described, the latching mechanism 162, where utilized, efiects a positive latching of the operating linkage so that the tongs may be lifted from the coil in the open position illustrated in FIG. 1. It is to be noted that in such position the lower link 84, formed of the spaced links 186 and N8, seats against the upper edge of the cam lug 132 to prevent further collapse of the toggle 78 beyond the position illustrated. It is also to be noted that in such position the grappling arms 30 and 32 seat against the pin 16%) to thereby limit pivotal movement of the grappling arms about their fixed pivots in a direction away from the internal diameter of the coil.

This invention provides tongs that can be readily constructed by anyone skilled in the art having the teachings of this invention before him, which tongs are strong and easy to operate while giving ample support to the coil without permitting sag of such coil. The invention makes it possible to effect economies in the handling or" strip material in that it definitely prevents damage to the coil of the type encountered through the use of the tongs of the prior art.

I claim:

1. Lifting tongs for the engagement and transportation of a coil of strip material comprising, a supporting frame member, a toggle disposed to be raised and lowered and to extend above said frame member, the toggle having a pair of lower links disposed to extend in opposite directions with, an end of each terminating within said frame member, means, for pivotally supporting said lower links within said frame member at a point spaced from said terminating end, two aligned pairs of opposed inner and outer grappling arms disposed within but having a lower end thereof extending below said frame member, a coilengaging shoe member carried by said lower end of each of the. inner and, outer grappling arms of the two pairs, means for pivotally supporting the inner grappling arms of the two pairs within said frame member, means conmeeting the terminating end of each of said lower links of the toggle to an associated one of the outer grappling arms whereby movement of the. outer grappling arms is effected in1 response to, pivotal movement of said lower links, means carried by each of the lower links and movable therewith disposed in sliding engagement with an associated one of the inner grappling arms to effect a pivotal movement thereof as the toggle is raised to move the shoe members carried thereby into engagement with the inner surface of the coil, the, connecting means between said lower links and the outer grappling arms including a lost motion means whereby movement of the outer grappling arms to move. the shoe members carried thereby into engagement with the outer surface of the coil as the t ggle is raised is delayed until after movement of the inner grappling arms is completed, and linkage, mechanism connecting the outer grappling arms to equalize the movements thereof and the pressures applied thereby to the coil.

2. Lifting tongs for the engagement and transportation of a coil of strip material comprising, a supporting frame member, a toggle disposed. to be raised and lowered and to extend above said frame member, the toggle having a pair of lower links disposed to extend in. opposite directions with an end of each terminating within said frame member, means for pivotally supporting said lower links within said frame member at, a point spaced from said terminating end, two aligned, pairs of opposed inner and outer grappling arms disposed within but having a lower end thereof extending below said frame, member, a coilengaging shoe member carried by said lower end of each of the inner and outer grappling arms. of the two pairs, means for pivotally supporting the inner grappling arms of the two pairs within said frame member, means connecting the terminating end of each of said lower links of the toggle to an associated one of the outer grappling arms whereby movement of the outer grappling arms is effected in response to pivotal movement of said lower links, means carried by each of the lower links and movable therewith disposed in sliding engagement with an associated one of the inner grappling arms to effect a pivotal movement thereof as the toggle is raised to move the shoe members carried thereby into engagement with the inner surface of the coil and to move the shoe members carried thereby away from the inner surface of the coil as the toggle is lowered, stop means carried by said frame member disposed to limit the pivotal movement of the inner grappling arms to move the shoe members carried thereby away from the inner surface of the coil to a predetermined equalized movement, the connecting means between said lower links and the outer grappling arms including a lost motion means whereby movement of the outer grappling arms to move the shoe members carried thereby into engagement with the outer surface of the coil as the toggle is raised is delayed until after movement of the inner grappling arms is completed, and linkage mechanism connecting the outer grappling arms to equalize the movements thereof and the pressures applied thereby to the coil.

3. Lifting tongs for the engagement and transportation of a coil of strip material comprising, a supporting frame member, a toggle disposed to be raised and lowered and to extend above said frame member, the toggle having a pair of lower links disposed to extend in opposite directions with an end of each terminating within said frame member, means for pivotally supporting said lower links within said frame member at a point spaced from said terminating end, two aligned pairs of opposed inner and outer grappling arms disposed within but having a lower end thereof extending below said frame member, a coilengaging shoe member carried by said lower end of each of the inner and outer grappling arms of the two pairs, means for pivotally supporting the inner grappling arms of the two pairs within said frame member, means connecting the terminating end of each of said lower links of the toggle to an associated one of the outer grappling arms whereby movement of the outer grappling arms is effected in response to pivotal movement of said lower links, means carried by each of the lower links and movable therewith disposed in sliding engagement with an associated one of the inner grappling arms to effect a pivotal movement thereof as the toggle is raised to move the shoe members carried thereby into engagement with the inner surface of the coil, the connecting means between said lower links and the outer grappling arms including a lost motion means whereby movement of the outer grappling arms to move the shoe members carried thereby into engagement with the outer surface of the coil as the toggle is raised is delayed until after movement of the inner grappling arms is completed, a pair of bell crank levers, each of the bell crank levers being pivotally mounted in spaced relation in the frame member and having a lower end thereof pivotally connected to an associated one of the outer grappling arms, and a connecting link pivotally connected between the pair-of bell crank levers to effect an equalization of the movement thereof and of the outer grappling arms connected thereto to equalize the pressures applied thereby to the coil.

4. Lifting tongs for the engagement and transportation of a coil of strip material comprising, a supporting frame member, a toggle disposed to be raised and lowered and to extend above said frame member, the toggle having a pair of lower links disposed to extend in opposite directions with an end of each terminating within said frame member, means for pivotally supporting said lower links within said frame member at a point spaced from said terminating end, two aligned pairs of opposed inner and outer grappling arms disposed within but having a lower end thereof extending below said frame member, a coil-engaging shoe member carried by said lower end of each of the inner and outer grappling arms of the two pairs, means for pivotally supporting the inner grappling arms of the two pairs within said frame member, means connecting the terminating end of each of said lower links of the toggle to an associated one of the outer grappling arms whereby movement of the outer grappling arms is effected in response to pivotal movement of said lower links, means carried by each of the lower links and movable therewith disposed in sliding engagement with an associated one of the inner grappling arms to efiect a pivotal movement thereof as the toggle is raised to move the shoe members carried thereby into engagement with the inner surface of the coil, and to move the shoe members carried thereby away from the inner surface of the coil as the toggle is lowered, stop means carried by said frame member disposed to limit the pivotal movement of the inner grappling arms to move the shoe members carried thereby away from the inner surface of the coil to a predetermined equalized movement, the connecting means between said lower links and the outer grappling arms including a lost motion means whereby movement of the outer grappling arms to move the shoe mem bers carried thereby into engagement with the outer surface of the coil as the toggle is raised is delayed until after movement of the inner grappling arms is completed, a pair of hell crank levers, each of the bell crank levers being pivotally mounted in spaced relation in the frame member and having a lower end thereof pivotally connected to an associated one of the outer grappling arms, and a connecting link pivotally connected between the pair of hell crank levers to effect an equalization of the movements thereof and of the outer grappling arms connected thereto to equalize the pressures applied thereby to the coil.

References Cited in the file of this patent UNITED STATES PATENTS 2,816,793 Elberty Dec. 17, 1957 2,830,842 Heppenstall Apr. 15, 1958

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