Patent GB-1080616-A (GB)
Title: Flying shear providing for multiple minimum cut-lengths and further variable cut-lengths
IPC: B23D36/00
Filed: 1966-05-24
Abstract: 1,080,616. Flying shears. HALLDEN MACHINE CO. May 24, 1966 [Aug. 4, 1965], No. 23170/66. Heading B3W. A pendulum or drum type flying shear has first and second turnable means operative during each revolution of the first means to move the blades once into and from shearing relation and also in the direction of moving stock at the time of cut and operative on turning movement of the second means in opposite directions at the time of cut to increase and decrease respectively the speed of the blades in the stock moving direction, power means including a clutch for driving the means on clutch engagement, a device measuring the length of stock advanced to the blades, such device being pre-settable for different cut lengths and operative to engage the clutch when the required stock length has been advanced, means to disengage the clutch after one cycle of the blades and other mechanism to operate the shear for two different minimum cut lengths at the same speed of the first means, comprising an eccentric operatively connected with the second means and driven through a clutch at the same speed as the first means, the eccentric being on disengagement of the second clutch adjustable into one of two different angular positions in which on reengagement of the clutch and drive of the eccentric it will turn the second means in opposite directions at the time of cut. The pendulum shear, Fig. 2, comprises a frame 14 which is oscillated by eccentrics 24 on a main shaft 26. A blade 18 is mounted on the frame and co-operates with a movable blade 20 which slides in guideways in the frame 14 and which is reciprocated by eccentrics 36 through connecting rods 34. The eccentrics 24 and 36 are displaced by 180 degrees. The bottom of the frame 14 is connected by a pivot 38 to an arm 40 the other end of which is mounted on an eccentric 42 journalled in the frame 12. The shear is driven by a variable speed motor through a one-revolution pneumatic clutch. Sheet metal is fed to the shear by pinch rolls and in turn drives an impulse generator connected to a counter which is part of a control mechanism for the clutch so that the shear operates after a predetermined length of metal has been fed. With the eccentric 42 stationary, the minimum length of sheet material which can be cut is when the shear operates continuously. Provision is made for cutting two different minimum cut lengths of material by providing a shaft which is driven at the same speed as the main shaft and to which the eccentric 42 can be connected by a dog-clutch. By disengaging the dog-clutch the initial position of the eccentric relative to the eccentrics 24 can be set so that the effect of the eccentric 42 is either additive or subtractive on the flying speed of the blades. The feeding speed of the material is adjusted to match the flying speed of the blades. The drum shear, Fig. 8.-The drive to the cutter drums 122, 124 is taken through a differential gear 132 and the casing 140 of the gear which carries the planet wheels 138 is connected to an eccentric 184 which corresponds to the eccentric 42. The connection is by an articulated arm 182 so that as the eccentric rotates the casing is oscillated and causes the speed of the drums to vary cyclically. Three conditions of the eccentric 184 are possible giving three basic minimum cut lengths for continuous operation of the shear. In a first condition the eccentric 184 is stationary and has no effect on the speed of the drums. In a second condition the eccentric is driven at the same speed as the drums and is positioned so that it imparts rotary movement to the casing and planet wheels in a direction opposite to the direction of rotation of the drums and thus reduces their speed. In a third condition the eccentric 184 is driven at the same speed as the drums and is positioned so that it rotates the differential casing in a direction to increase the drum-speed. Since the feeding speed of the material is matched to the flying speed of the blades at the time of cut, correspondingly different lengths of material will be cut.