The Number Theory System PARI

A staple driving device comprising a nosepiece assembly including a rigid structure having opposed flat side surfaces defining the sides of a drive track for guidingly engaging the legs of a leading staple during the driving movement thereof, a forwardly facing flat surface extending between the side surfaces for guidingly engaging the rear surface of a leading staple during the driving movement thereof, and longitudinally extending surfaces defining an opening of a staple-shaped configuration extending forwardly into communication with the drive track defining surfaces, and a rigid member mounted on said rigid structure forwardly of said staple-shaped opening for (1) translational movement in a direction parallel with the movement of the staple driving element between a locked operating position and a raised unlocked position and (2) pivotal movement between the raised unlocked position and a forwardly extending open access position, the rigid member having (1) staple stop surfaces facing rearwardly when the rigid member is in its locked operative position for engaging the forward surface of a leading staple after the feeding movement thereof, (2) staple guiding surfaces facing rearwardly when the rigid member is in its locked operative position for guidingly engaging the forward surface of a leading staple during the driving movement thereof, and (3) cam surfaces extending upwardly and forwardly from the upper end of staple stop surfaces when the rigid member is in its locked operative position operable (1) when the rigid member is pivoted from its unlocked position into its open access position to permit limited forward movement of a leading staple feed through the opening, and (2) when the rigid member is pivoted from its open access position to move a leading staple rearwardly into a position of alignment with the drive track.