Lifting tongs

Claim 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 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.

Claim 3

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.

Claim 4

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.