GB1378777A - Zigzag blanking device for use in a press - Google Patents

Abstract

1378777 Zig-zag punching AIDA ENG Ltd 14 Jan 1972 1775/72 Heading B3W A zig-zag blanking device comprises a punch holder 3 and a die holder 4 arranged to traverse in unison an intermittently advancing strip A to be blanked, the traversing movement being effected by intermittently rotating a rotary disc 13 provided with an eccentric pin 14 through 180 degrees alternately in opposite directions. The die holder 4 is mounted in gibs (7), (Fig. 3, not shown) for sliding movement in the press frame 6 from left to right and back as seen in Fig. 2. An extension 10 of die holder 4 has a groove 11 in its underside in which a block 15 is slidable. Loosely fitting in the block is the pin 14 which is mounted on the disc 13 by means of a screw 17, secured to the plate at 16 and in threaded engagement with the pin. The pin is eccentrically disposed on the disc relative to a shaft 12 which rotates the disc so that rotation of the plate causes the holder 4, and through guides 5 the holder 3, to move to the left or right depending on the direction of rotation, the block 15 sliding along the groove 11. The eccentricity of the pin relative to the shaft is varied, to vary the travel of the holders, by rotating the screw 17. The drive to the shaft 12 includes a sun and planet gear arrangement 27, 28, the gear 28 being rotated about its own axis and about gear 27 by a gear 33 driven by a gear shaft (34), Fig. 5 (not shown), from the press drive shaft. A pin 30 on the gear 28 fits loosely in a member 26 slidable in a groove 25 in the underside of a reciprocable member 22. The member 22 slides on guides 21 and is connected to a rack 19 which meshes with a pinion 18 on the lower end of the shaft 12. In operation, the gear 33 is rotated through 180 degrees per press cycle, moving the gear 28 about the gear 27 while the gear 28 rotates about its axis. The eccentric pin 30 moves the member 26 along the groove 25 in one direction and then the other during one rotation of the gear 28 around gear 27 and thus reciprocates the member 22 and the rack 19. The shaft 12 is thereby rotated through 180 degrees alternately in opposite directions, to move the punch and die assembly between punching positions. The portions d-a and b-c of the path C of pin 30 correspond to the holders 3 and 4 being stationary and on either side of these portions the speed of the holders is reduced or increased which avoids the adverse effects of inertia.