Patent ID: 7328642

Claim:
A hole-punching assembly structure for hole-punching unit, comprises a positioning piece, a clamping piece, a plurality of tool holders, two balancing rods and a plurality of hole mountings, wherein each end of the positioning piece couples to one of the plurality of hole mountings via one of two balancing rods, each one of the plurality of tool holders goes through the positioning piece axially for the positioning piece to fix each one of the plurality of tool holders, each one of the plurality of tool holders having a first end extending to one of the plurality of hole mountings and a second end being blocked by the clamping piece, thereby allowing the clamping piece to force the plurality of tool holders to move axially for hole-punching operation, the positioning piece comprising a main plate, the main plate having one retaining edge disposed protrudently at each side thereof, each retaining edge having a gliding rail concavely formed towards an end thereof and in symmetry with another retaining edge, the gliding rail having an end contiguous to the main plate and connected to a receiving slot, and the retaining edge forming a confining part along an outer rim of the receiving slot; the clamping piece having an elastic plate contiguous to the main plate, the elastic plate having one rod disposed at each end thereof, each rod having a first end and a second end protruded through the receiving slot respectively, the confining part being used for restraining each rod to fix the clamping piece.