In the downstroke of the press slide and punch-holder 1, the upper flange of member 2 pushes roller a downward, turning lever 3 and cam 4 counterclockwise about a fixed axis. As cam 4 turns, it pushes plunger 5 downward so that punch 6 forces work 7 between the ends of side punches 10 and 11 causing the tabs of the work to be bent upward. As the press slide continues moving downward, spring 9 returns plunger 5 to its upper position and cams b and c apply pressure to sliding side punches 10 and 11, moving them toward the centre. This bends over the tabs of work 7. As punch-holder 1 begins its upstroke, the lower flange of member 2 turns lever 3 clockwise so that cam 4 again pushes plunger 5 downward and punch 6 presses tightly on the folded tabs of work 7. At the same time, springs 12 and 13 return side punches 10 and 11 to their initial position. Thus, in one downstroke and one upstroke of punch-holder 1, three processing operations are performed. Spring 14, backing up lower die member 8, compensates for the added thickness of the folded-over tabs and eliminates bottoming of punch 6.
$3223$CmL,HP$