Patent ID: 7354250

Claim:
An apparatus comprising: a slot defined between eccentric bushes; a latch pin fitted to a rotary shaft such that it is latched to the slot; and a restraint unit to restrain the eccentric bushes when the rotary shaft is rotated, the restraint unit comprising: a restraint member mounted in the rotary shaft to move forward or rearward in a radial direction of the rotary shaft, the restraint member having a hollow portion; a supporting shaft extending from the latch pin to be inserted into the hollow portion of the restraint member; a return spring interposed between an outer circumference of the supporting shaft and the restraint member to move the restraint member inward toward the center of the rotary shaft when the rotary shaft is not rotated; an inwardly protruding portion formed in the restraint member to support one end of the return spring; and a nut being fastened on a distal thread portion of the supporting shaft extending in the restraint member to support the other end of the return spring.