US2685974A

US2685974A - Mechanical loading tongs

Info

Publication number: US2685974A
Authority: US
Publication date: 1954-08-10
Anticipated expiration: 1971-08-10

Description

Aug. 10, 1954 Filed July 25, 1952 W. P. KERN MECHANICAL LOADING TONGS 2 Sheets-Sheet 1 INVENTOR Woooeow P KEEN,

Aug. 10, 1954 w. P. KERN MECHANICAL LOADING TONGS 2 Sheets-Sheet 2 Filed July 25, 1952 4 4 Q7 V V 5 M)? 4,4; 7% 3 F 0 m ATTORNEYS Patented Aug. 10, 1954 3 UNITED STATES'PATENT OFFICE MECHANICAL LOADING TON GS Woodrow P. Kern, Rainier, Wash.

Application July 25, 1952, Serial No. 300,822

' 2 Claims.

I This invention relates to a mechanical loading tongs, adapted to be mounted upon a conventional power shovel. V The following are objects of the invention:

/ First, to provide a tongs or grapple that can be mounted on power shovels without requiring extensive modification thereof; and

Second, to provide a tongs that is under. the control of the operator at all times.

Other objects will appear from the following description, the claims appended thereto, and from the. annexed drawing, in which like reference characters designate like partsthroughout the several views, and wherein:

Figure l is a side elevation of a shovel having the tongs mounted thereon; I

Figure 2 is an enlarged top plan view of the tongs;

Figure 3 is a sectional View on line 3-3 of Figure 2;

Figure 4 is a sectional view on line 4-4 of Figure 3;

Figure 5 is a side elevation of the tongs, the lower ends of the tong members being broken away;

Figure 6 is a section on line 6-6 of Figure 5; and

Figure 7 is a View similar to Figure 3 in which the upper portion of the structure is broken away,

showing a modification.

A power shovel l6 has a boom l2 provided intermediate its ends with a toothed drum I4 in mesh with the dipper stick l6. At the outer end of the boom is a sheave l8, and a conventional series of operating cables are trained over the sheave, for the purpose of controlling the swinging of the boom and dipper stick. All this is conventional and does not per se form part of the invention. 7

Secured rigidly to the outer end of the dipper stick is a U-shaped extension 20, projecting longitudinally of and beyond the dipper stick and having its bight formed with a head block 22. The head block is formed with a centrally disposed bore24 opening upon the top and bottom surfaces. of the block.

A stub shaft 26 is rotatable within the bore and is integral with a reduced upper end portion 28 projecting above the "upper surface of block 22. integrally with a fiat, enlarged head 30 which in the present instance, but not necessarily, is of rectangular outer configuration.

Keyed to the portion 28 is a large pulley 32 overlying the top surface of the head block 22.

At its lower end, the shaft is formed anti-friction means 34 being interposed between the pulley and block and being formed, in the illustrated embodiment of the invention, as a ball hearing.

The portion '23 is externally threaded, and threaded'iy engaged thereon is a nut 36 that holds the pulley and end portion 28 assembled.

To the underside of the head 36 I weld spaced eyes 38, loosely receiving depending yokes 46 of inverted u shape. The upper ends of crossed tong members 42 are extended between the legs of the respective yokes and are pivotally joined to the yokes. The lower ends of said members are curved inwardly toward one another as at 42 for engaging an object, not shown, to be lifted. Intermediate their ends, the tongs are pivotally joined by a pivotpin 46.

The tongs normally swing to the closed position shown. Means is provided, however, for

54 depending from the bight of a bracket 56 of inverted U shape straddling and fixedly mounted upon the head block 22. The cable 50, after being trained about the sheave, is passed over the boom sheave l8, and extends to the cab of the shovel, where it is wound upon 'a reel 58. The reel is rotatable in opposite directions, under the control of the operator, by any suitable mechanism, not shown.

Means is also provided for rotating the connected tong members about an axis normal to the axis of pin 46. To this end, the pulley 32 is circumferentially grooved as at 66, a cable 62 extending within the groove about the pulley.

Cable 52 extends along the dipper stick, through an eye 64 on the stick, and is windable upon a spool 66 located within the cab and rotatable by a suitable mechanism, not shown.

The winding of the cable 62 upon the spool is adapted to rotate the pulley 60, and hence stub shaft 26, head 38, and tong members 42, in one direction. Movement thereof in a reverse direction is provided for by a spring 68, connected at one end to lug won the extension 20, and at its other end to an eye bolt 12 threaded in and extending radially of the pulley 32. That end portion of the cable 62 that is trained about the pulley is also connected to the eye bolt. When the cable 62 is wound upon the spool 66, the spring will be placed under tension. Thereafter,

when the spool is freed for rotation in a cableunwinding direction, the spring will return to its normal condition and will rotate the pulley in a reverse direction. The bolt 12 is so located, it should be noted, as to halt the reverse rotation of the pulley at a location in which the tong members will be disposed in a plane aligned longitudinally with the dipper stick.

To impart to thestructure greater versatility in handling objects to be loaded, I provide, at opposite sides of the head 30, upwardly curved horns 16, and a horn 18 may also be forwardly directed from the head block 22.

Figure '7 shows a modified connection of the tong members to the head 30, that eliminatesthe shackles or yokes 40. Depending, spaced eyes, welded to the block 30, have parallel, spaced apart legs 80, 82 of different lengths, merging into converging bight portions84. The bights of the respective eyes of the modified form are thus of acute angled configuration, and are extended downwardly and in-the direction of one another.

Receivedin-therespective bights of the eyes are connecting pins 86, that slide upwardly and downwardly uponthe'bight portions-8t responsive to opening and closing of thetong members.

Important characteristics of the invention are as follows:

First, the invention canbe mounted upon the dipper stick oi-a conventional-power shovel; and

secondythetongsare under the positive control of the shovel operator-at a11- times, not only w'ithmespectto opening and closing of the tong jaws, but also'with respect torotation-of the tong members about "an axis normal to the axis of 7 their pivotal connection'to one another.

It is believed clear thatthe invention is not necessarily confinedto the'specific use or uses thereof described above, since it maybe utilized for anypurposeto which itmay be suited. Nor is the 'invention'to be necessarily limited to the specific construction illustrated and described, since such construction is only intended to be illustrative of the principles of operation and the "means presently devised to carry out said principles, it being "considered that the invention comprehends-any minor change in construction thatmaybe permitted within the scope of the appended claims.

'What is claimed is:

1. In a loading device, the combination, with a dipper stick mounted upon and extending outwardly-of a power shovel, of a head block mounted at the outer end of the dipper stick, 'saidheao. I block having an aperture centrally thereof; a stub shaft rotatablymounted in'the aperture of the head block'for rotary movement about an axis normal to the longitudinal center line of the dipper stick; a head rigid with said stub shaft and disposed beyond one end of the head block; a-pulley secured to the stub shaft for rotation therewith'beyond the other end ofthe head block; a flexible element trained about said pulley .and having one end extended inthe direction of the inner end of the dipper stick; means at said one end'of the'fiexible .element arranged for shifting the elementin one direction under the control of an operator, for rotating the head in one direction; a spring connected at its opposite ends to the other end of the flexible element and tothe dipper stick respectively and tensioned to normally shift the element in an opposite direction, to impart return rotary movement to the head, the head having an axial bore extending therethrough and continuing through the stub shaft and pulley; a pair of eyes depending from one end of the head and disposed at opposite sides of said bore; a pair of tong members depending from saidieyes. said tong members having upper ends joined to ;the eyes by pivotalconnections shiftable radially of said bore, the tong members having crossed intermediate portions and articleengaging jaws at their lower ends; a pivot pin connecting the crossing portions of the tong members and=arranged normally to the axis of rotation of the'head; a cable connected at one end .to the pivot' apinzand extending axially of and center bore openingupon the top and --bott0m surfaces of the-block astub shaft rotatable withinthe bore ofthe head block, said stub shaft being formed integrally with a reduced upper end portion projecting above the upper end surface of the block and being further-formed integrally with an-enlarged head engaged against the lower end surface of the head block; a stub shaftdr-ive pulley secured to =the upper end portion of said stub shaft for rotation with the stub shaft; means for rotating said pulley for imparting rotatablemovement to the stub shaft; eye means dependingfrom-said head ofthe stub shaft and 'spaced diametrically of said head at opposite sides of the axis of rotation of the stub shalt; crossed tong members pivotally connected to one another intermediate the opposite ends thereof and having pivotal-connections at one end tosaid :eyemeans, said stub shaft-having an end'to end bore aligned with the center of rotation :of the stub shaftand' head; and acable elementextend- 1in g through said bore oft-he stub shaft and-shiftablelongitudinally of the stub shaft, said cable element being connected to thejtong members at "the pointer pivotal connection-of the-tong'members-to one another, for opening and closing the tang members responsive to movement of the cable element longitudinally of the stub shaft bore.

"References Cited in'the'flle or this patent 'UNITEDSTATES PATENTS