Patent GB-490291-A (GB)
Title: Improvements in and relating to presses for cutting sheet metal
IPC: B21D28/08
Filed: 1937-02-11
Abstract: 490,291. Punching. RHODES, C. J. Feb. 11, 1937, No. 4079. [Class 83 (iv)] Metal-sheet feeds.-In a "stagger " type of sheet-metal punching-press with a step-by-step feed first in one direction and then after displacement in the opposite direction, means is provided for automatically taking a single sheet from a stack, and presenting it to grippers, which automatically grip it and subsequently free it after it has been completely perforated. As shown, a gravity slide 6 is mounted on a transverse slide 2 carrying racks which are reciprocated in opposite directions through gearing 11, rods 7a, 8a and pawls 9, 10. The movement is in timed relation with the operation of the punch over the die x. An arm 12 is tripped after each row of holes partly to rotate a shaft 13 having staggered projections 14 and carried by the slide 2. The sheets s are maintained in position in a magazine 25 by upstanding lugs and a rubber sucker 35 descends against the action of a spring on to the top sheet. Compressed air applied to the left-hand end of the cylinder 18, with reference to Fig. 2, moves a piston rod 18b and thereby a plate 29 carrying the sucker supporting rods 33. The rods pass through lugs 34 and are operated by linkage from a cam 77 on a shaft 67 to raise and lower the suckers. A cam 84 on the same shaft actuates valve operating linkage to connect the suckers to the suction side of a pump or to the atmosphere. A third cam 92 on the shaft 67 actuates linkage operating a valve connected to a reservoir supplied with compressed air from the pump. The valve has a neutral position and two other positions making connection of the respective sides of the cylinder 18 with the reservoir. A similar operation of another three way valve is made by a fourth cam 102 to supply compressed air to the lower end of a cylinder 45 to hold the gravity slide 6 in its upper position. A fifth cam 107 operates a roller 108, arm 109, shaft 110, arm 112, and link 113, connected to the main machine clutch. A lever 114 is operatively connected to a one revolution clutch, which clutches a worm wheel 68 to the shaft 67 to depress the suckers. The second cam 84 causes suction to be applied, and the cam 77 raises the suckers and sheet from the magazine. Thereupon the third cam brings the compressed air into action in the cylinder 18 to move the plate 29 laterally. The cam 77 depresses the plate on to the lateral slide. Compressed air is applied momentarily to the right-hand end of the cylinder 18 to cause the sheet to be moved into engagement with a stop 120. The cam 102 then causes compressed air to be removed from lower end of the cylinder 45. The gravity slide can then move down until a pawl 15 engages the top projection 14. A forked member continues downward and causes a bell crank to be rotated and the upper edge of the sheet to be gripped. The second cam cuts off suction from the suckers and the first cam moves to raise the suckers. The third cam then moves for the return of the suckers to the initial position and the fifth cam causes the press to be put into operation. When the last row has been punched the slide 6 engages a projection and the press is stopped.