Joiners cramp for piping - has jacking arm sliding along leg of L=shaped bar locked by wedging action with counter couple applying ball to leg

摘要

The cramp, comprises an 'F' shaped e.g. steel frame (1,6,7) of which the lower arm (1) is slidably mounted on the leg (6). This arm (1) has a threaded bore (8) for a transverse screw (9) upon which the movable jaw (10) and a handle (H) are mounted, also equipped to lock onto the leg by a wedging action. A rectangular window (2) in the base of the arm (1) allows the passage of the leg (6), accommodating a socket for a locking ball (5). An arm nib (4) may locate the ball socket, nominally offset below the arm (1) and in the angle subtended with the leg (6). The screw (9) is rotated to wedge a workpiece (11) between the movable jaw (10) and the upper fixed arm (7). The jacking reaction is provided by an arm couple. This couple results in an intense localised pressure applied by the ball (5) to the leg (6), locking the arm (1) in the required position.