Patent ID: 7628103

Claim:
A punching apparatus for punching a plurality of holes through an edge portion of a stack of papers, the apparatus comprising: a frame; a document support providing a document supporting surface configured to receive the stack of papers in a punching position wherein the edge portion of the stack of papers extends in a longitudinal direction; a plurality of punches provided in a row extending in the longitudinal direction, each punch comprising a punching end configured to punch through the stack of papers in a punching direction generally perpendicular to the longitudinal direction to form the plurality of holes, a driving end, and an internal bore extending therethrough from the punching end to the driving end, the bore being open to the punching end for enabling document segments punched from the stack of papers to pass therethrough as the punch is driven through the edge portion of the stack of papers; a punch drive system comprising a shaft extending in the longitudinal direction, one or more cams fixed on the shaft, and a driver for selectively rotating the shaft; each cam being positioned adjacent the driving end of an associated one of the punches, each cam having a camming portion configured to apply force to the associated punch in the punching direction by engaging the driving end thereof in a camming action as the shaft is rotated to thereby drive the punching end thereof through the edge portion of the stack of papers to form the plurality of holes; and a relief opening provided for each associated punch and camming portion, the relief opening being communicated to the internal bore at least when the camming portion is engaged in the camming action with the driving end of the associated punch for enabling the document segments passing through the internal bore to exit the internal bore, the relief opening being provided either (i) by a pair of spaced apart walls on the driving end of the punch configured to engage the camming portion of the cam such that the relief opening is disposed between camming surfaces formed by the spaced apart walls, or (ii) on the camming portion of the cam such that the relief opening is disposed between camming surfaces of the camming portion.