US1839389A - Lifting tongs - Google Patents

Description

Jan. 5, 1932. M. R HEPPENSTALL ,3

LIFTING TONGS Filed April 11, 1931 IN'VENTOR WITNESS Patented Jan. 5, 1932 UNITED s'rATEs PATENT QFFICE MAX 3. HEPPENSTALL, OF PITTSBURGH, PENNSYLVANIA, ASSIGNOR TO HEPPENSTALL COMPANY, OF PITTSBURGH, PENNSYLVANIA, A CORPORATION OF PENNSYLVANIA LIFTING TONGS Application filed April 11,

This invention relates to lifting tongs having a latch for alternatelyholding grapplingmembers in open position and releasing them. Particularly, it relates to tongs of the type shown in U. S. Patent No. "1,506,827 to Gellert.

. The object of the invention is to'improve and to simplify the construction of lifting tong latches of the typeherein contemplated to the end that they may be. economically manufactured from few parts, that wear on i the parts may be reduced, and that-the tongs may have a wide opening and closing range for engaging articles of a large range 0 sizes or dimensions.

The preferred embodiment of this-invention is illustrated in the accompanying drawings, wherein :Fig. 1 is a fragmentary elevation of upper toggle links locked to lower grappling arms in open position, with the walls of the upper latch element in, vertical section; Fig. 1A a corresponding assembly of tongs suspended and locked in open position; Fig. 2 a fragmentary elevation of the toggle links and grappling arms in partly unlocked position with the walls of the upper latch element in vertical section; Fig. 2A

a corresponding assembly of open tongs as. they-are brought to rest upon an object; Fig. 3 afragmentary elevation of the toggle links and grappling arms in unlocked and lifting position with the walls of the upper latch element in ve-rtical section; Fig. 3A a corresponding assembly of tongs closed to lift an object; and Fig. 4 a horizontal section on line A-A of Fig. 1 through the connecting pin,

and showing in plan the lowerlatch element or keeper.

' The drawings illustrate ingot tongs having suspension means 1, toggle or link arms 2 pivoted at their upper ends to each other and to the suspension means, and grappling arms 3 pivoted together at 4 and having their upper ends pivoted at 5 to the lower ends of links 2. Two separable latch members 6and 7 are fastened rigidly to a link arm 2- and to a grappling arm 3, respectively, and extend inwardly toward each otherf Preferably, pivot pins 20 and 4 of the tongs extend .t-hrough these latch members, and, in ad- 1931. Serial No. 529,381.

dition, upper latch element 6 is bolted to its link arm and an edge of lower latch element 7 is welded to the outside of its grippling arm. These latch elements may be otherwise secured to the tongs, and,-if desired, may be Preferably, the bottom pin 9 is provided with an elongate head 10, adjacent to which there is a neck 11 forming a shoulder 12 with the main body of the pin. Thus, pin 9 enters keeper 7 when the head 10 of the pin is parallel to sl0t'8, and it is locked to the keeper by rotation. Preferably, for a reason presently to be explained, neck 11 is of such length as to afford vertical play of the pin in slot 8. Upper latch element or sleeve 6 encloses the upper end of pin 9, and is provided interorly with a series of cams 13 and 14, preferably formed on cylinders detachably connected to sleeve 6. Pin 9 is supported within sleeve 6 by lateral lugs 15 preferably formed integrally with the pin and lying between these cam surfaces. Cams 13 and 14 are of such configuration that as sleeve 6 and pin 9 move longitudinally with Felation to each other the pin is rotated by engagement of its lugs 15 with the cams, such rotation causcngaged by and released from keeper 7.

Lugs 15 of pin 9 are preferably substan-,

f the relative positions of the slot and pmp ing the lower ends of pin 9 to alternately be bases disposed vertically (Fig. 3). Corres vertical faces which limit the turning of the pondingly, the cams include substantially pin by their sloping faces. Each upper cam 13 overlaps a lower cam 14: to-turn lugs 15 angularly as they are pushed up from lower cam 14. Therefore, the narrow width of lugs 15.afl"ords appreciable clearance between lugs 15 and thelower points of upper cams 13, and

wear of the points of the cams is accordingly eliminated or materially reduced. Preferably the upper and lower cams are angularly disposed forty-five dcgres apart from each other, each cam. being ninety degrees 1 n length so that the head 10 of the pm 9 is alternately turned parallel to and at right angles to slot 8 of keeper '2'.

In operation, the tongs may initially be assumed to be suspended freely, with the grappling arms locked in open position, as illustrated by Figs. 1 and 1A.. In this posi tion, lugs 15 at the top of pin 9 rest at the bottoms of lower cams 1a and suspend pin 9 in such position that its'lower headlO engages keeper 7 beneath and transversely of slot 8. As shown in Figs. 2 and 2A, when the tongs are lowered until they rest upon an object, such as an ingot 16, shoulder 12 of pin 9 is supported upon keeper 7 so that pin 9 is restrained from descending further. Sleeve G-then telescopes downwardly upon the pin bringing an upper cam 13 into engagement with lugs 15 to rotate the pin 9 so as to turn its head 10 forty-five degrees to partially unlatched position. Neck 11 above lug 10 is of such length that during this interval lug 10 is spaced below the slotted surface of keeper 7. With the tongs thus partial ly unlatched, they are raised to again bring a cam 14 against lugs 15 to cause pin 9 to be rotated to complete its ninety degree turn.

This'places the head of the pin parallel to slot 8,-and, as the pin remains substantially vertical, it is withdrawn by the further raising of the tongs. Latch members 6 and 7 thus are separated, and grappling arms 3 close upon the object to be engaged by them.

As shownin Figs. 3 and 3A, the latch imposes no restriction upon the size of objects which may be engaged by the'tongs. In the closed position of the tongs, pin 9 is suspended by its upper lugs 15 from sleeve 6, and prevent from rotation by the engagement of its lugs 15 by cam 14. As the tongs arelowered and the object released, lower head 10 of pin 9 readily re-enters slot 8 of keeper 7.- Shoulder 12 above head 10 comes to rest on the upper surface of keeper 7 to prevent further downwardmovement of pin 9, and upper cam 13 descends with sleeve 6 to engage lugs 15 and rotate the pin forty-five degrees to a cross position under slot 8 of the keeper. Then, as the tongs are lifted, cams 14 complete the rotation of pin 9 to ninetyf degrees where the latch elements are in completely locked position to hold grappling arms 3 open, as shown initially in Figs. 1

and 1A.-

According to the provisions of the Patent ever, I desire to have it understood that, within the scope of the appended claims, the

aesaaeo invention may be practiced otherwise than as specifically illustrated and described.

I claim:

1. In a lifting tongs, the combination with pairs of pivotally connected grappling arms and closing links forming a toggle, of a latch comprising a member rigidly attached to one of said links, a pin suspended from said member for rotary and longitudinal movements therein, and a keeper rigidly attached to one of said arms, said member and pin being provided with interengaging cams and lugs for rotating said pin upon longitudinal movement thereof by the opening and closing of the tongs, and said keeper and the lower end of said pin being provided with interengaging elements for locking the tongs in closed position, the lower end of the pin being free from the keeper when the tongs are unlocked.

2. In a lifting tongs, the combination with pairs of pivotally connected grappling arms and closing links forming a toggle, of a latch comprising a sleeve rigidly attached to one of said .links and provided interiorly with oppositely-disposed pin-engaging cams, a pin suspended from said sleeve and provided with lugs engaging the cams thereof for rotating the pin upon its longitudinal movements within the sleeve, and a keeper rigidly attached to one of said arms, said keeper and the lower end of said pin being provided. with interengaging elements for locking the tongs in closed position, the lower end of the pin being free from the keeper when the tongs are unlocked.

3.. In a lifting tongs, the combination with a pair of pivotally connected grappling arms and closing links forming a toggle, of a latch comprising a sleeve rigidly attached to one of said links and. provided interiorly with oppositely-disposed pin-engaging cams, a pin suspended from said sleeve and provided with lugs engaging the cams thereof for rotating the pin upon its longitudinal move-. ments within the sleeve, and a keeper rigidly attached to one of said arms and provided with an elongateslot, the lowerend of said pin being provided with'an elongate head for engaging said keeper. through said slot therein.

In testimony whereof, I sign my name.

MAX R. HEPPENSTALL.

Images