Patent ID: 7251973

Claim:
A hydroforming apparatus for hydroforming a workpiece, the apparatus comprising: a die comprising: a lower die section mounted in a lower die holder; an upper die section mounted on an upper die holder; at least one of the upper and lower die holders being movable relative to the other between an open position, in which the workpiece is positionable between the upper and lower die holders, and a closed position, in which the lower and upper die sections combine to define a die cavity therebetween in which the workpiece is hydroformed; each of the upper and lower die holders comprising an outer surface respectively; an outer ring subassembly comprising: a ring; at least one first cam segment attached to an inner surface of the ring; at least one second cam segment; at least one tapered wedge positioned between said at least one first and second cam segments; the second cam segment being movable between an open position, in which the second cam segment is disposed distal to the first cam segment, and a closed position, in which the second cam segment is disposed proximal to the second cam segment; at least one biasing means for biasing said at least one second cam segment to the closed position; said at least one tapered wedge being movable between an extended position, in which said at least one second cam segment is pushed by said at least one tapered wedge to the open position, and a retracted position, in which said at least one second cam segment is moved to the closed position by said at least one biasing means; said at least one second cam segment including a lower surface shaped to engage the outer surface of the upper and lower die holders; and the outer ring subassembly being movable between a forward position, in which the lower surface of said at least one second cam segment engages the outer surface upon said at least one tapered wedge moving to the extended position, and a returned position, in which the lower surface is disengaged from the outer surface.