US2394779A - Adjustable tongs - Google Patents

Description

Feb. 12, 194s. J. A. HUNTER ET AL ADJUSTABLE Tones Filed May 29, 1944 3 Sheets-Sheet 1 FIE- E- Il 11M/l Il Ma l .fa/7W 4 Hlm/75 md y HAC-@M4N Maag? FCB. i2, 1945. J. A HUNTER ET AL 2,394,779

ADJUSTABLE TONGS 3 sheets-'sheet 2 :dg y M7 M h www k 1&5. y Hh. f W J w w i f M Feb. i2, 194.16.

J. A, HUNTER x-:TAL

ADJUSTABLE ToNGs Filed May 29, 1944 3 Sheets-Sheet 3 'In :"Il lll fllh y j j! i I ll /meizfa Patented Feb. 12, 1946 2,394,779 ADJUSTABLE 'roNGs John A. Hunter, Pittsburgh, and Herman E.

Muller, Sr., Swissvale, Pa., assignors to Carnegie-Illinois Steel Corporation, a corporation of New Jersey Application May 29, 1944, Serial No. 537,872

6 Claims.

One object of the invention is to provide lifting 5 tongs capable of handling an increased range of body sizes and still stay within the vertical clearance available for engaging and disengaging them.

While not limited thereto, the invention is 1o peculiarly well suited for application to a conv` ventional type of lifting tongs used for transporting ingots to the soaking pits of a steel mill.

For a completeunderstanding of the invention, reference should be made to the following detailed disclosure, the accompanying drawings, and the appended claims.

In the drawings:

Figure l is an elevation of ingot lifting tongs embodying the herein claimed invention.

Figure 2 is an elevation at right angles to Figure l.

Figure 3 is anenlarged detail section on line III-III of Figure 2, with the pivotal centers for the tongs shown in position for engagement with large sized workpieces..

Figure 4 is a horizontal section on line IV-IV of Figure 3.

Figure 5 is a view similar to Figure 3, but showing the pivotal centers for the tongs shifted to `3 positions t0 adapt the tongs for handling smaller Workpieces.

Figure 6 is a horizontal section on line VI-VI of Figure 5.

Figure 7 is a fragmentary detail section on line VII--VII of Figure l.

Referring in detail to the drawings, I0 represents the housing of ingot-lifting mechanism of conventional construction adapted to be suspended from a carriage traveling on a suitable overhead crane (not shown). Rotatably supported by the housing I0 is aspindle I2 having a gear I4 secured thereto, meshing with a pinion I6 carried by a shaft I8 adapted to be rotated under manual control of the crane operator so as to turn the spindle about its vertical axis when desired, in order to rotate the ingot suspended from the tongs in a manner well known to those skilled in the art. Securely bolted and keyed to the spindle I2 is a pair of complementary memA 5 bers 2li-2D having converging guideways 22 formed therein for coaction with tong-actuating rollers 24 rotatably mounted near the free extremities 0i arms 26 forming the upper portions of the gripping'tongs 28. Each tong 28 includes a gripping jaw 30 carrying an inserted tooth 32 adapted to dig into and grip an ingot or other workpiece 34.

The present invention is directed particularly to an improved mounting for the tongs 28, so arranged that the pivotal center oi at least one of the tongs can be shifted relatively to its supporting hanger 36 so as to thereby vary the 'gripping range of the tongs independently of the normal extent of movement of the members 20 with relation to the hanger 36. In the preferred embodiment of the invention illustrated each tong is pivotally supported on an intermediate portion 38 of a pin indicated as a Whole at 40 having axially aligned journal portions 42 and 44 which are eccentric to said portion 38. The journal portions 42 and 44 are seated in respective bores 46 and 48 formed in hub extensions 50 and 52 formed integrally on the hanger 36. The journal portions 42 and 44 are of different diameters, but are both concentric to the same longitudinal axis, as indicated by the point :r in Figures 3 and 5. The pivotal tong-supporting portion 38 of each pin is eccentric to the point at, the center of the circular supporting portion being indicated at the point y in Figures 3 and 5. The amount of eccentricity is indicated by dimension arrows z in Figures 3 and 5.

Extending longitudinally through each tong pivot pin is a hole 54 to accommodate a bolt 56 loosely tted therein and having integrally secured thereto a head 58 which constitutes a keeper the central portion of which is seated in a slot 60 formed in an extension 62 projecting outwardly from the trunnion portion 44 of the pin. Another portion of the keeper is seated in a slot 64 formed in the cuter face of the extension 52 of the hanger. The end of the bolt 56 remote from the keeper carries a washer 66 of a diameter slightly greater than the trunnion portion 46. The washer is retained in place by castellated nut 68 screwed on the end of the bolt and locked in position by a suitable cotter pin. The washer and nut are surrounded by a shroud portion 'I0 formed on the hub extension 50. This shroud portion forms a recess I2 and thus protects the Washer and pin from splashing metal and slag. In a similar manner, the keeper 53 is protected by a shroud portion 14. The shroud portions shield the parts from splashing metal or slag freezing to the parts, and they also protect the pivotal mounting from striking against objects such as ingots, ingot molds, and the like, during the normal operation of the apparatus.

In normal operation of ingot lifting tongs, when l the members 28-20 are moved upwardly with respect to the hanger 36, the wedging or cam action of the guides 22 will rock the tongs about their pivotal supports and thus cause the teeth 32 of the jaws to approach one another and firmly grip the ingot or similar workpiece. To release this` grip, tension is applied in the conventional man-` ner to a pull rod T6, causing the hanger '36 to approach the members 20, whereupon the camming action of the wedge guideways 22 causes the tong jaws 30 to swing outwardly away from one another and thus release their grip on the ingotV or workpiece.

Since the working stroke of the members 20 of.V

the tong mechanism is usuallyrxed by limits of the design of existing apparatus, such as crane runways and roof structures. it governs the number of sizes of workpieces which can be handled. i

since the normal gripping range of the tong is a function of the stroke of said members 20. With the'improved eccentric pin mountingof the present invention herein'shown and described, the gripping range of the tongs can be easily and quickly increased, for exampleirom the minimum range of Figures 5 and 6 to the maximum gripping range of Figures. 3 and 4, by simply turning the'eccentric pins 4i! for a half revolution. To do this it is necessary merely for the operator to remove'thenuts S8 and washers l515 and disengage the keepers 58 from the slots 60 and 54, whereupon a special wrench is `engaged with the slot B; so as to eiect the turning of each pin from the position of Figure 5 to the position of Figure 3. This adjustment will bodily shift the pivotal axis for-each tong a distance equal to twice the eccentricity as measured between the points :c and y. vAfter the adjustmentgthe bolt 56 will be reinserted through the hole 54, and the keeper por'- tion 58 engaged with the slots 60 and llill, wherel upon the washers 6'6 and nuts 68 will be assembled in position to thus lockthe tongs intheir new position.v It is to be noted that the centers :c and y, in the positionsof either Figure 3 or Figure 5, are-in the same horizontal plane. Thus the eccentric centers are in dead center relation7 and no torque is transmitted to thekeeper 58 of the bolt 5S when the tongs are in load-*sustaining conl dition. Y

The eccentric pin tong pivotal support, constructed, proportioned, and arranged as shown, 1

is advantageous since such design permits renewal and replacement of the pivot pins, when necesl is of smaller diameter than the circularY hole in the tong which accommodates. the pivotal por- Desirably, lthe diameter of the journal tion 38. portion A2 is equal to the diameter ofthe pivotal portion 38 minus the eccentricity e as measured between the points :c and y, and similarly the diameter of the journal portion 44 is desirably equal tothe diameter of the'pivotal portion 38 plus the l eccentricity a measured between points x and y. As'thus proportioned, it is apparent that the smaller circular journal portion 4.2 is tangent to thevr circle dening the pivotal portion 38 on one end, and similarlyy the larger circular journal portion. at the other end is tangent to the circle i ofthe` pivot portion38. Such tangency of these parts is apparent from an inspection of Figures 1, 3, 4, 5, and 6. f f

Iflromthe drawings when read in connection with the foregoing description, it will be apparent that our invention provides for quickly and easily varying the gripping range of lifting tongs independently of the normal extent of movement of the tong-actuating member with respect to the hanger on which the tongs are mounted, and it will also be apparent that the design and construction of the parts is such that the tong-supporting pins can be quickly and easily dismantled or assembled for replacement or repair by an endwise movement. The parts as shown and described are of rugged construction, and are so arranged that they can be quickly and safely `adjusted by relatively unskilled labor.

While we have described a preferred construction the utility of which has been demonstrated by an actual reduction tol practice, it is to be understood'that various modications and substitutions of equivalents may be made without departure from the invention as defined in the allpended claims.

We claim':

1. Lifting apparatus of the character described, comprising a suspended hanger, work-gripping tongs pivotally supported thereby, a member movable relatively to the hanger and carrying means for rocking the tongs upon movement of the member relatively to said hanger, an eccentric pin for shifting the pivotal centerrof at least one of said tongs relatively to said hanger so as to vary the Y gripping range of said tongs independently of the normal extent of movement of said member with relation to said hanger, the hanger being provided with respective'shroud portions surrounding and protecting the outerY extremities of said eccentric pm.l

2. Lifting apparatus of the character described, comprising a suspended hanger, work-gripping tongs lpivotally supported by said hanger, a member movable relativelyv to the hanger and carrying means for rocking the tongs upon movement of the spindle relatively to said hanger, and an eccentric pin for shifting the pivotal center of at least one of said tongs relatively to said hanger.

so as to vary the gripping range of saidV tongs independently of the normal extent of movement of said member with relation to rsaid hanger, said pin having a slotted extension at one end thereof, a keeper coacting therewith normally locking the with respective shroud portions surrounding and protecting the outer extremities of said eccentric 3. Lifting apparatus of the character described, comprising a suspended hanger, work-gripping tongs pivotallyA supported by said hanger, a member movable relatively to the hanger and carrying means for rocking the tongs upon movement of the member relatively to said hanger, pivot pins for said tongs having journal portions seated in said hanger and which are eccentric to the pivot portions of the pin on whichithe tongs are mounted, removable keeper means normally locking said pins against turning, the hanger being provided Ywith respective shroud portions surrounding and protecting the outer extremities of said eccentric pin.

4. Lifting apparatus of the character described, comprising a suspended hanger, work-gripping tongs pivotally supported by said hanger, aV member movable-relatively to the hanger and carrying-means for rocking the tongs upon movement of the spindle relatively to said hanger, pivot pins forjsaid tongs having journal portions seated in ..75 said hangers which are eccentric to the pivot porpin against turning, the hanger being providedY tions thereof on which the tongs are mounted, each pivot pin having a longitudinally extending bore therethrough, a slotted extension on said pin, and a bolt extending through said bore and having a keeper head seated in said slotted extension, said hanger having respective shroud portions adjacent the extremities of said journal portions of said pins and adapted to shield them from splashed molten metal or slag.

5. Lifting apparatus of the character described, comprising a hanger, Work-gripping tongs pivotally supported by said hanger, pivot pins for said tongs having concentric circular journal portions at the opposite ends thereof of different diameters, each pin having an intermediate circular portion eccentric to said journal portions on which the tongs are mounted, the smaller journal portion being tangent to the intermediate porj tion and the larger journal portion being tangent to the intermediate portion, the points of tangency of said journal portions being diametrically opposite, each pin having a longitudinally-extending bore therethrough, a bolt extending through said bore and having the keeper head engaging a slot formed in the larger journal portion and an aligned slot formed in said hanger,

said bolt carrying a washer adjacent the smaller journal portion which is of a diameter larger than said smaller journal portion, and a retaining nut carried by said bolt, the parts being thus constructed and arranged so that the pivot pin can be readily disengaged from theA tong and the hanger for replacement or repair by an endwise movement upon removal of said bolt, nut, and Washer, said hanger being provided with respective shroud portions extending axially beyond the end of said bolt and beyond the outer face of said keeper head.

6. Lifting apparatus of the character described, comprising a suspended hanger, Work-gripping tongs pivotally supported by said hanger, a member movable relatively to the hanger and carry ing means for rocking the tongs upon movement of the member relatively to said hanger, and pivot pins for said tongs having journal portions seated in said hanger, the hanger being provided with respective shroud portions adjacent the outer extremities of the journal portions of said pins and adapted to shield them from splashed molten metal or slag. Y

JOHN A. HUNTER. HERMAN E. MULLER, Sn.

Images