Patent GB-1089088-A (GB)
Title: Flying shear of variable cut lengths
IPC: B23D25/04
Filed: 1966-07-29
Abstract: 1,089,088. Flying shears. HALLDEN MACHINE CO. July 29, 1966 [Aug. 4, 1965], No. 34118/66. Heading B3W. A flying shear comprises co-operating blades mounted on an arm for moving the blades back and forth along the stock feed path on oscillation of the arm, and for guiding one blade in shearing relation with the other, and three eccentrics power driven at the same speed, the first and third eccentric being driven in the same direction, of which the first eccentric turnably supports the arm, the second eccentric is pivotally connected to the one blade by a follower strap and the third eccentric has a follower strap pivotally connected to the arm at a point remote from the first eccentric and means for disengaging the first and third eccentrics from and re-engaging them with the power means to permit angular adjustment of the disengaged eccentrics relative to each other and to the second eccentric so that on their reengagement the combined oscillation given by them to the arm will be of correspondingly different amplitudes. The shear is adapted to cut rods and comprises an apertured die 30 mounted on a frame 26 which slides on a base 20. A co-operating apertured cutter 36 slides in guides 32 in the frame and is reciprocated by an eccentric 72 which has a follower strap 70, pivotally connected to the cutter carrier. The frame 26 is reciprocated along the feed path by an oscillating arm 44, which is connected to the frame by a link 54. The arm is mounted on an eccentric 46 (the " first " eccentric) and is pivotally connected at its lower end 58 to the follower strap 60 of an eccentric 62 (the " third " eccentric). The rod s is fed to the cutters through a guide 40 by opposing cooperating chains 80 (Fig. 1). With the eccentrics 72, 46 and 62 in the relative positions shown in Fig. 3, the cutter is in its top-most position and the combined effect of the eccentrics 46 and 62 is to cause the amplitude of oscillation of the arm 44 to be a maximum. Shear drive.-A motor 90 drives the feed chains 80 at constant speed and also drives a shaft 124 which carries one sun-wheel 126 of a differential gear 128. The second sun-wheel 132 is connected to the shear input drive-shaft 168 through a clutch 160 and gears 164, 166. The motor 90 also drives an infinitely variable speed gear 140, the output shaft of which is connected to the planet wheel carrier 130 of the differential gear 128. With the rod being fed at constant speed, the length cut will vary as the operating speed of the shear is varied, thus if the cut length is to be increased the speed of the shaft 168 is reduced so that the time interval between successive cutting actions of the dies is increased and a greater length of rod passes through the dies meanwhile. The input shaft 168, carries a gear 174 which meshes with a similar size gear 176 on the shaft 64 of the synchronizing eccentric 62, and with similar gears 170, 172 which respectively drive the eccentrics 46 and 72. The gears 176 and 170 are locked to their respective shafts by dog clutches and pointers 216, 214 indicate the position of the major axis of the eccentric relative to the gear, by scales 212, 210. Operation.-The relative positions of the eccentrics shown in Fig. 3 is that necessary when the shear is set for cutting the rod into maximum lengths. If shorter lengths are to be cut, then the speed of the shaft 168 is increased to reduce the duration of the operating cycle. This increase of the operating speed of the shear also increases the reciprocating speed of the frame 26, so that it will no longer correspond to the feed speed of the rod, which is constant. The speed of the frame, at the instant of cutting, is reduced by rotating the shafts 64 and 48, relative to their driving gears and in opposite directions. The extreme position is that in which the eccentrics have each been rotated 90 degrees from the position shown in Fig. 3 and there will then be no motion of the frame 26 at the instant of cutting. Miss-cut device.-The pivoted joint between the follower strap 70 and the cutter carrier 34 includes an eccentric 244 which is rotated through a rack-and-pinion 250, 252 by a fluid cylinder 256. The control of the cylinder is not described. Pendulum shear.-A similar system of eccentrics is employed for controlling the amplitude of oscillation of a pendulum shear, Fig. 7 (not shown) but in this case the speed of operation of the shear is constant and the speed of the stock is varied to match the speed of the shear by a differential gear in the drive to the rod feed rolls 310.