When piston 1 is moved to the right by fluid entering the left end of cylinder 5, movable jaw 2 clamps workpiece 3 which is mounted on fixed locating pin 4. At the same time, the action of the fluid moves cylinder 5 with wedge member 6 to the left, clamping workpiece 3 with the second movable jaw 7. When the workpiece is clamped, wedge member 6 and a similar wedge member at the left end of the piston rod spread springs members 8 at the ends of the movable jaws, thereby jamming the jaws in their guides.
$3742$SHP,GC$