GB1274799A - Improvements in or relating to shearing machines - Google Patents

Abstract

1,274,799. Flying shears. ZDARSKE STROJIRNY A SLEVARNY NARODNI PODNIK. 4 June, 1970 [13 June, 1969], No. 26924/70. Heading B3W. A flying shear which can readily be adapted to cut stationary material comprises a frame 4, a lower cutter 12 pivotally mounted in the frame, an upper cutter 10 mounted on an eccentric shaft 5 also mounted in the frame, a pair of arms 13 rigid with cutter 12 being connected to a pair of arms 14 rigid with cutter 10 by eccentric pins 17 adjustable to vary the cutting clearance, and means 20-22 for moving the lower cutter along the feed path of material to be cut. An electric motor 27 drives the shaft 5 through gearing, a mis-cut eccentric shaft 7, feed rolls 2 through variable-speed gearing and a shaft 26, Fig. 2, which drives a crank 20 for synchronizing the movement of the cutters with the movement of the material to be cut. A connecting rod 21 is pivotally connected with a nut 22, which is movable along a slot in the lower cutter support 11 by means of a screw 23 driven by a motor 25, to vary the radius R 2 according to the length of stock to be cut so that at the moment of cutting the horizontal component of velocity of the lower cutter 12 is equal to the stock velocity. A selsyn or other indicator indicates the adjustment of the nut and thus the length to be cut. To extend the range of possible cut lengths a mis-cut device is provided in the drive to the eccentric shaft 7 comprising clutches (43), (44) Fig. 3 (not shown) which can be selectively engaged to vary the transmission ratio. If only basic lengths are to be cut the shaft is located in its uppermost position and does not rotate, the clutch 43 locking the shaft to the drive housing 3. The drive to the feed rolls 2 includes a clutch 46, a differential gear 50 and a variable speed gear-box 52. The drive to the shaft 26 carrying the crank 20 includes a clutch 36. For cutting stationary sheet material the drive to the feed rollers and to the shaft 26 is interrupted by disengagement of clutches 36, 46 and application of brakes 37, 47. Auxiliary feed rollers are actuated when the clutch 46 is disengaged.