GB739074A - Improvements in or relating to a machine for cutting or creasing sheets of paper, card of the like - Google Patents

Abstract

739,074. Cutting-machines. BACKHOUSE H. T. Oct. 21, 1953 [Oct. 21, 1952], No. 26454/52. Class 31 (1). [Also in Group XVI] A machine for cutting or creasing a paper sheet 94, Fig. 1, comprises a flat bed 20 with projecting cutting or creasing blades 21, a presser 24 having an arcuate surface and arranged so that, by reciprocation of its centre of curvature in a direction parallel to the bed, its arcuate surface rolls over the bed and presses the sheet against the blades, a sheetfeeding carriage 41 which is arranged to reciprocate with the presser in such a manner that in its forward movement it feeds a sheet into position on the bed while the presser makes an idle stroke in advance of the carriage and in its rearward movement returns empty while the sheet is held and pressed against the blades by the returning presser, and one or more suction grippers 59 for holding the sheet during its forward movement. The machine is generally similar to that described in Specification 721,875, the presser 24 being shaped as a sector of a cylinder and having a roller 25 running on a guide 23; the presser is connected at 30 with a link 31 attached to the crank-pin 32 on a driven shaft 35 and has an arcuate gear 27 meshing with a fixed rack 28. The carriage 41, which runs on guides 40 at the sides of the bed, is connected for reciprocation with the presser by a pin 43 on the roller 25 engaging a slot 44 in the carriage. In the machine shown in Fig. 1, the sheets are fed singly on to a downwardly-inclined feed board 80 from which they pass on to a grid 50 on the carriage. The feed board has a side lay for positioning the side of a sheet and front registers formed by arms 81 on a cross-shaft 82 oscillated through linkage 86 from a cam 83 on the shaft 35. The grid has two suction grippers 59 upstanding from a cross tube 56 connected centrally with a source of suction; one end of this tube is permanently closed and the other controlled by a valve plate actuated by abutments 69 70 at opposite ends of the stroke of the carriage. When the carriage reaches its rearmost position, the abutment 69 closes the valve plate so that the grippers hold the sheet which has been correctly positioned by the registers 81. The cam 83 then rotates the shaft 82 to lift the registers and cause rollers 91 carried by arms 90 on the shaft to press down upon the sheet in overlying relation to the grippers. The abutment 70 opens the valve plate at the end of the forward movement of the carriage so as to release the sheet for cutting or creasing on the return movement of the presser. Front lays and grippers 93 on the presser, as described in Specification 739,087, register the front edge of the sheet and hold it during the interval from the start of return movement of the carriage to the time when the presser grips the sheet against the blades. Forward feed of a sheet into the machine may be prevented by pedal-operated mechanism which holds the register 81 in gripping position and renders the abutment 69 ineffective to close the valve plate. If desired, two grippers may be arranged as shown in Fig. 7 to stretch the front edge of a sheet between them by one gripper 59b being spring-urged from the other 59a which has its position controlled by a cam 102 so as to move inwardly as the carriage approaches the end of its return stroke and outwardly at the start of the forward stroke; the gripper 59b may have a lesser grip than has the gripper 59a by providing it with a smaller area of grip, reducing the suction applied to it by a small bleed, or ensuring that the spring 103 urging it outwardly cannot overcome the grip of the other gripper. The machine may be modified by sloping the bed 20 and guideway 23 downwardly as shown in Fig. 8, and arranging for the carriage 41 to travel horizontally on the guides 40, or by replacing the grid 50 by a conveyer 110, Fig. 9, having on its rear roller 111 a gear 114 meshing with a fixed rack 115; in the latter case, a one-way clutch between the gear and roller provides for the drive of the conveyer only during the return of the carriage and at a speed which is either equal to or slightly greater than the rate at which the carriage moves rearwardly, whereby the front edge of the sheet is urged into contact with stops on the presser. The Provisional Specification describes also the use of mechanism for registering the side edges of a sheet shortly before the carriage reaches the end of its forward movement.