| 摘要 |
<p>In a piercing die assembly for punching a plurality of radially extending holes in a tubular member, a die structure having an upper open end for receiving a tubular member to be punched and with the die structure having means for supporting the tubular member in a pre-punching position including radially inner and outer die walls for backing up inner and outer wall surfaces of the tubular member to be punched, a plurality of spaced radially movable punch assemblies operatively connected with the die structure and having a series of radially movable punches, the punch assemblies having bearings positioned at radially outer ends of the punches and with each bearing and its associated punch being radially movable simultaneously together, a vertically movable ring-shaped actuator member positioned radially outwardly of the punches and movable axially from a pre-punching position to a post-punching position, a plurality of spaced cams mounted on the ring-shaped actuator member and movable up and down therewith from a pre-punching position to a post-punching position and with the cams being positioned for contacting and actuating the bearings and the punches to punch holes in the tubular member in a preplanned manner, press means for moving the actuator member from its pre-punching position and actuating said cams to actuate the punches to punch the tubular member, each of said cams being associated in radial adjacency with an associated one of said punch assemblies and workable together for punching holes in the tubular member, means for returning said press means to its pre-punching position, and retraction means for retracting the bearings and the punches after completing a punching operation to place the punches in readiness for another punching operation.</p> |
