US3572808A

US3572808A - Lifting tongs

Info

Publication number: US3572808A
Application number: US774795A
Authority: US
Inventors: Boyd Columbus Miller
Original assignee: Individual
Current assignee: Individual
Priority date: 1968-11-12
Filing date: 1968-11-12
Publication date: 1971-03-30
Anticipated expiration: 1988-03-30

Abstract

The present invention is directed to an improved lifting device for lifting steel beams and girders such as the type used in heavy construction work and comprises a scissorslike pair of tongs with inturned flanges that are so formed as to close around one flange of a beam for lifting and transferring the beam, properly oriented, into position. A latch holds the arms of the tongs apart when no load is being carried, as for example, after a load has been deposited.

Description

United States Patent 2,415,898 2/1947 Meadows 294/106 2,668,733 2/1954 Boticki 294/1 18 3,201,167 8/1965 Wamplerm. 294/106X 3,348,872 10/1967 Kolinski 294/1 19X Primary ExaminerHarvey C. Hornsby Assistant Examiner-Douglas D. Watts Att0rneysClifton T. Hunt, Jr., Charles R. Rhodes and Hunt,

Heard & Rhodes ABSTRACT: The present invention is directed to an improved lifting device for lifting steel beams and girders such as the type used in heavy construction work and comprises a scissorslike pair of tongs with inturned flanges that are so formed as to close around one flange of a beam for lifting and transferring the beam, properly oriented, into position. A latch holds the arms of the tongs apart when no load is being carried, as for example, after a load has been deposited.

PATENTED HARBO I971 INVENTOR B Y "Mum W M41 LIFTING TONGS The present invention utilizes the principle of the scissors and ice tongs in an apparatus for lifting heavy beams and girders and moving them about from one place to another. Moreover, the present invention enables an I-beam to be lifted into position for assembly while keeping the web of the beam vertical at all times and generally in the same position in which it will be fixed in place. This can be very beneficial, especially in the construction of tall buildings or where the beam is positioned in difficult, hard to get to places. The device herein described inherently releases its grip on the beam when the weight of the load is removed and a latch mechanism locks the lifting legs in the open position for removal from the load and during the transfer back to the pick up station while empty. As a result of the minimization of the necessary operating space, the steel beams or girders themselves may be stored or stacked closer together in the storage position than has heretofore been possible.

A further refinement of the device includes a notch or indent in each of the inturned flanges for providing clearance for those beams having reinforcing stiffeners which might otherwise interfere with the lifting operation. The improved tongs maintain a solid grip on the beam throughout lifting, even in the presence of ice, grease, wet paint or other slippery substances, since the heavier the load, the tighter the grip.

It is therefore an object of the invention to provide an improved device which may be removably suspended from the hook of a crane for lifting and emplacing heavy girders and beams while maintaining them in a properly oriented working position.

It is another object of the invention to provide a device which permits a smooth and easy pickup of heavy beams and girders and a means for locking the tongs in an open position while empty, thereby facilitating removal of the tongs from one load and proper placement about another load.

It is yet a further object of the invention to provide an improved lifting device for heavy beams and girders whereby the load itself provides the means for tightening the grip thereon, and the heavier the load, the tighter the grip.

The various features of the invention will be apparent from the following description of an illustrated embodiment thereof, which should be read in conjunction with the accompanying drawings, in which:

FIG. I is a perspective view of the improved device constructed in accordance with the present invention, and showing the device being used to lift a beam keeping it in the working position;

FIG. 2 is a perspective view similar to FIG. 1 but looking at the other side and showing the invention locked in the open position; and

FIG. 3 is a perspective view of the device removed from its environment and toward the closed position.

Referring more particularly to the drawings, in FIG. 1 the reference number broadly indicates a set of lifting tongs according to the present invention suspended from the hook H of a crane and supporting a beam G. The lifting tongs 10 comprises essentially four major elements: a first arm 20, a second arm 30, a lifting ring 40, and a latch mechanism broadly indicated at 50.

Arm comprises a main body portion 22 including an opening through the upper end thereof and a gripping member or hand 24 welded or otherwise secured to the lower end of the arm, terminating in an inturned flange 26 which bears against the undersurface of the upper cross flange F and supports the weight of the beam or girder G. A handle 28 is attached to the edge of body portion 22 near the lower end thereof, to be used by a workman in locating the tongs at a desired point along the beam.

Arm 30 is similar to arm 20, comprising a body portion 32 having an opening through the upper end thereof and a gripping member or hand 34 at the other or lower end ter-' minating in anintumed flange 36. A handle 38 similar to handle 28 is similarly positioned on the edge of body portion 32 for the same purpose as that of handle 28.

Guide loops

42 and 44 are pivotally attached to the upper ends of

arms

20 and 30 respectively by any suitable means, for example by

rods

46 and 47 extending; through the terminal ends of

loops

42 and 44 respectively and extending through the said openings in the upper ends of

body members

22 and 32. Loops 42 and 44 extend loosely about ring 40 and serve to slidably retain ring 40 in a prescribed position relative to the upper ends of

arms

22 and 32. Ring 40 further includes a transverse locking bar 48 secured as at 49 to the outer periphery of the ring at a position between the two

loops

42 and 44. Locking bar 48 is permanently secured to the periphery of locking ring 40 and is adapted to be moved into and out of engagement with

notches

56 and 57 in the locking member 50 as hereinafter described. Latching mechanism 50 comprises a web 51 and a pair of downwardly extending legs Hand 53 which receive locking ring 40 therebetween. A pivot pin 54 joins the lower ends of

legs

52 and 53 remote from web 51, and also serves to pivotally connect

arms

20 and 30. At a point approximately halfway between the extremities of the latching mechanism, each

leg

52 and 53 includes

respective indents

56 and 57 which are adapted to receive locking bar 48 to hold the

gripping members

34 and 24 apart as the device is being removed from or positioned about an upper flange F or moved from position to position without any load therein. In the locked position described above,

loops

42 and 44 prevent outward movement of the upper ends of

arms

20 and 30, and the inner edges of the: upper portions of the arms engage the outer periphery of ring 40 to prevent the arms from coming together.

In operation, the locked device, as shown in FIG. 2, is lowered until inturned

flanges

26 and 36 are slightly below the flange E of a beam to be lifted, and slightly spaced laterally therefrom. The operator spins the locking ring 40 counterclockwise in FIG. 2 moving the locking rod 48 out of engagement with

indents

56 and 57, causing the web 51 to move downwardly by gravity toward the ring 40 and imparting corresponding downward movement to the pivot pin or rod 54. The downward movement of pivot pin 54 causes inward movement of the upper ends of

arms

20 and 30 and corresponding inward movement of the

gripping hands

24 and 34 toward the closed position shown in FIG. 1. As the crane operator applies a lifting force on the device, the inturned

flanges

26 and 36 securely grip the under edges of the flange F of the beam for lifting.

The greater the weight, the tighter will be the grip on the beam, since the vertical force downward will tend to pull the arms together during lifting. The beam is lifted keeping the web of the beam in a vertical or working position and the beam is moved directly into place, without requiring any twisting or turning to properly orient it for assembly.

When the beam has been moved to a desired location, the

gripping members

24 and 34 may be released by merely lowering the device until the pressure is removed from inturned

edges

26 and 36 and the locking rod 4 8 is lowered toward the

notches

56 and 57. Meanwhile, the pivot pin 54 rises causing outward movement of the gripping

members

24 and 34 as the web 51 rises within the ring 40. At this point, a workman may rotate the ring 40 clockwise in FIG. 2 until rod 48 is in engagement with

indents

56 and 57. This locks the device into open position, so that it may be easily removed from about flange F and retained in open position until it is properly placed about another beam to be moved, where the process begins again.

An additional feature of the device is the provision of

notches

27 and 37 in

flanges

26 and 36 respectively. The function of these notches is to provide clearance for the inturned

flanges

26 and 36 in case the beam is provided with stiffeners or ribs R at the point where it is desired to lift the beam. In such a case the ribs R are received within the

notches

27 and 37, and do not interfere with the operation of the device.

Although the present invention has been described in detail, it is recognized that departures may be made therefrom within the scope of this invention, which is to be limited only by the scope of the claims which follow:

lclaim:

l. Lifting tongs for transferring and emplacing relatively heavy construction elements such as beams and girders comprising a pair of arms positioned in scissorslike arrangement, pivot means connecting said arms to each other at the point where the two arms cross, said arms being reciprocally movable around the pivot means between an open position where the lower ends of the arms are spread apart and a closed position wherein the lower ends are close together, said lower end of each arm terminating in a gripping hand including an intumed lower edge, said lower edges having a longitudinal dimension extending in a direction perpendicular to the plane of said arms, a first means for connecting the upper ends of said arms to a lifting crane whereby when a lifting force is applied to the upper ends of said arms, the weight of the load causes the lower ends to move toward each other tightening the grip, a second means for supporting said tongs independently of said first means, said second means comprising an upstanding leg connected at its upper end to said crane and at its lower end to said pivot means and having a notch spaced above said pivot means, a locking bar extending transversely across the path of and between said reciprocally movable anns and selectively engageable with said notch in said leg.

2 Lifting tongs for transferring and emplacing relatively heavy construction elements such as beams and girders comprising a pair of arms positioned in scissorslike arrangement, pivot means connecting said arms to each other at the point where the two arms cross, said arms being reciprocally movable around the pivot means between an open position where the lower ends of the arms are spread apart and a closed position wherein the lower ends are close together, said lower end of each arm terminating in a gripping hand including an intumed lower edge, said lower edges having a longitudinal dimension extending in a direction perpendicular to the plane of said arms, a first means for connecting the upper ends of said arms to a lifting crane whereby when a lifting force is applied to the upper ends of said arms, the weight of the load causes the lower ends to move toward each other tightening the grip, a second means for locking said arms in said open position comprising an inverted U-shaped locking member including a web and a pair of parallel, downwardly extending legs extending loosely about said ring and attached at their lower end to said pivot means below said ring, each of said legs including a locking indent in corresponding edges thereof, and a transverse locking bar secured to said ring and movable therewith between said loops, said bar being responsive to rotation of said ring to move into engagement with said indents for locking said arms in the open position.

Claims

1. Lifting tongs for transferring and emplacing relatively heavy construction elements such as beams and girders comprising a pair of arms positioned in scissorslike arrangement, pivot means connecting said arms to each other at the point where the two arms cross, said arms being reciprocally movable around the pivot means between an open position where the lower ends of the arms are spread apart and a closed position wherein the lower ends are close together, said lower end of each arm terminating in a gripping hand including an inturned lower edge, said lower edges having a longitudinal dimension extending in a direction perpendicular to the plane of said arms, a first means for connecting the upper ends of said arms to a lifting crane whereby when a lifting force is applied to the upper ends of said arms, the weight of the load causes the lower ends to move toward each other tightening the grip, a second means for supporting said tongs independently of said first means, said second means comprising an upstanding leg connected at its upper end to said crane and at its lower end to said pivot means and having a notch spaced above said pivot means, a locking bar extending transversely across the path of and between said reciprocally movable arms and selectively engageable with said notch in said leg.

2. Lifting tongs for transferring and emplacing relatively heavy construction elements such as beams and girders comprising a pair of arms positioned in scissorslike arrangement, pivot means connecting said arms to each other at the point where the two arms cross, said arms being reciprocally movable around the pivot means between an open position where the lower ends of the arms are spread apart and a closed position wherein the lower ends are close together, said lower end of each arm terminating in a gripping hand including an inturned lower edge, said lower edges having a longitudinal dimension extending in a direction perpendicular to the plane of said arms, a first means for connecting the upper ends of said arms to a lifting crane whereby when a lifting force is applied to the upper ends of said arms, the weight of the load causes the lower ends to move toward each other tightening the grip, a second means for locking said arms in said open position comprising an inverted U-shaped locking member including a web and a pair of parallel, downwardly extending legs extending loosely about said ring and attached at their lower end to said pivot means below said ring, each of said legs including a locking indEnt in corresponding edges thereof, and a transverse locking bar secured to said ring and movable therewith between said loops, said bar being responsive to rotation of said ring to move into engagement with said indents for locking said arms in the open position.