GB774562A - Improvements in machines for the die-forming of metallic sheet elements - Google Patents

Abstract

774,562. Stamping. COSTRUZIONI MECCANICHE BENELLI GAVAZZI SOC. AR.L. Jan. 13, 1955 [Sept. 11, 1954], No. 1063/55. Class 83 (4). A machine for perfoming successive pressing operations on sheet metal workpieces comprises a number of stationary dies 8 arranged in a circle, a number of complementary dies 7 on a frame 6 movable on guides 4 by a crankshaft 13 and connecting rod 14, a circular conveyer ring 44 with grippers 56a for conveying workpieces from one station to the next and at least two feed stations which are external to the circle of dies 7, 8 and at which dies 7a, 8a cut out the workpiece from strip and perform the first pressing operation. At each feed station the strip is fed by means 16 across pivoted bridges 17 to a die 8a. After the workpiece has been cut out and preliminarily pressed by the dies 7a, 8a, a cam 19 on the shaft 13 acts through a lever 20 to raise the bridges 17, a cam 37a moves grippers 33 together to grip the workpiece and a crank 40 on a shaft 41 driven by the shaft 13 moves a member 31 on which the grippers 33 are pivoted inwards to transfer the workpiece to a block 24. The die 8a is preferably at a lower level than the dies 8 and tha block 24 can be raised to the higher level by springs under the control of linkage 26, 27 co-operating with a cam 28 on the shaft 13. The conveyer ring 44 is indexed by a pawl 48 on a ring 49 oscillated by a pinion 50 engaging a toothed arc on the ring 49 and driven by a gear sector 51 oscillated by a cam 54 on the shaft 13. A pawl 55 for locking the ring 44 in indexed position is operated by another cam 54a. Each gripper 56a on the ring 44 is closed on the workpieces by springs and is opened when the frame 6 is lowered for the pressing operation by a cam surface 63 acting on a roller 60 on a rod 59 connected to the gripper linkage. The pressed workpieces are expelled from the dies by ejectors each operated by a rod 65 and a lever 66 having a roller engaging a cam surface 67 adjustably fitted on a cylinder 11 above the frame 6. The lower end of the cylinder 11 is connected to cylinders 12 containing a compressed fluid such as air, in order that the piston 10 connected to the frame 6 may cushion the movement of the frame.