Patent GB-762495-A (GB)
Title: Mechanism for slitting sheet material
IPC: B26D5/02
Filed: 1954-11-04
Abstract: 762,495. Slitting paper &c. TIMSONS, Ltd., and TIMSON, E. A. Jan. 26, 1955 [Nov. 4, 1954], No. 30486/53. Class 31 (1). In mechanism for slitting paper or other sheet material comprising a rotatable knife blade co-operating with an anvil, the knife blade is mounted for movement away from the anvil in two directions transverse to each other by cam means to facilitate introducing the paper between the blade and anvil. In the form shown, the mechanism is mounted between two triangular side-plates 5 which are connected to each other by rods 2, 8 and a shaft 35. The rod 8 has mounted thereon a campiece 10 movable by a hand lever 13 and provided with an edge cam 11 which is adapted to co-operate with an edge cam 16 provided on a cam-piece 15 secured to a sleeve 9 rotatable and longitudinally displaceable on the rod 8. The cam-piece 15 is provided with a pin 17 movable in a recess 18 in the cam-piece 10. A knife blade 31 co-operates with an anvil 38 in the form of a dished disc and is mounted on a shaft 19, Fig. 4, which is carried by bearing sleeves 20 each representing the forward end of an arm 55 which at its other end is formed as a further bearing sleeve 56 which loosely surrounds the sleeve 9. Each bearing sleeve 20 has an extension 21 provided with a lateral projection 22 received between the jaws 24, 25 of a U-shaped holder 26 which is secured to the sleeve 9. The initial angular setting of the arms 55 is adjustable by set-screws 29. A compression spring 30 extends between one of the holders 26 and a sideplate 5. The side-plates 5 are adjustable laterally of uprights 1, e.g. of a printing-machine, by means of screws to vary the width of paper cut. The cam means may be operated mechanically. A plurality of knife blades and anvils may be provided. In operation, when it is desired to part the knife blade from the anvil, the hand lever 13 is swung in a clockwise direction from the horizontal position shown in Fig. 4. During the first ninety degrees of this movement, the turning of the cam-piece 10 on the rod 8 causes the edge cam 11 to ride down on the edge cam 16 so that the spring 30 can operate to move leftwards on the rod 8, Fig. 2, the complete assembly of the sleeve 9, holders 26, arms 55, shaft 19, knife blade 31, and cam-piece 15 so that the knife blade 31 is moved laterally away from the anvil 38. During this movement of the hand lever 13, the pin 17 runs idly in the recess 18. Continued movement of the hand lever 13 causes the trailing edge of the recess 18 to move the pin 17 to turn the cam-piece 15 with the cam-piece 10 and hence the sleeve 9 to turn on the rod 8. As a result, the cutter assembly is swung upwards about the axis of the rod 8 to part the knife blade from the anvil in a vertical direction. When it is desired to return the parts to their operative position, the lever 13 is swung in the opposite direction so that the edge cam 11 engaged behind the edge cam 16 turns the campiece 15 and hence the sleeve 9 and cutter assembly in the opposite direction. At a predetermined point, one of the sleeves 20 abuts against a stop bracket 54, Fig. 2, provided on one of the uprights 1, to prevent further turning of the cutter assembly and sleeve 9, so that further turning of the lever 13 continues to rotate the cam-piece 10 but in such a way that the edge cam 11 co-operates with the edge cam 16 of the now non-rotating cam-piece 15 to force this and the sleeve 9 and cutter assembly longitudinally of the rod until the knife blade again abuts against the anvil.