Patent GB-697324-A (GB)
Title: Sheet registering mechanism
IPC: B41F21/10
Filed: 1950-06-30
Abstract: 697,324. Feeding sheets. HOE & CRABTREE, Ltd., R. June 30, 1950 [July 1, 1949], No. 16456/50. Class 100(i) In a sheet-feeding mechanism comprising a sheet support, means for registering a sheet thereon, and grippers for taking the registered sheet, a sheetdetector mechanism and a sheet-rejecting mechanism controlled thereby are provided whereby the edge of an improperly registered sheet is lifted from the support so that the sheet cannot be taken by the grippers. The invention is shown as applied to a registering cylinder 1 included in sheet-feeding apparatus as disclosed in Specification 478,362, wherein sprocket-wheels on each end of the cylinder carry a pair of conveyer chains having sheetgripper 'bars 20, Fig. 2, thereon adapted to be positioned within a gap in the cylinder. Grippers.-The gripper bars are tubular, have operable gripper elements actuated by a common member, and each bar is supported in turn in the cylinder gap on rollers 21, as described in Specification 695,941. Each gripper has a lower fixed jaw 22, and a pivoted upper jaw 23 which is normally closed by a spring-pressed rod 25, and opened by one of a number of arms 26 secured to a shaft 14 extending across the cylinder and rocked by cam means. Registering means.-Sheets S, Fig. 11, are fed over the shell 6 of the cylinder, a support bar 30, and an adjustable register bar 40, up to a front register stop member 45 which is initially moved away from the bar 40 by lever arms 46 and returned under the action of springs 48 to register the front edge of the sheet. Before the return of the stop member 45, suction is applied to the sheet through a passage 31 and holes in the bar 30, so that the front portion of the sheet is buckled. The register bar 40 is secured to the bar 30 by eccentric stud and elongated slot means which permit distortion or bowing of the bar 40 as described in Specification 631,010. The front register member 45 is carried by the arms 46 rotatably mounted on a shaft 47; other arms (not shown) are fixed to the shaft which is rocked to move back the member 45 against the springs 48. The member 45 can flex to conform with the bar 40. Sheet-detecting and rejecting means.-The detector means comprises a number of pivoted fingers 60, Fig. 5, which are all swung counterclockwise against the action of springs 67, by the front edge of a properly registered sheet, so that the lower edges of the fingers do not impede the upward movement of blocks 66 carried by a rock shaft 65. If one detector finger 60 has not been moved by the sheet, the shaft 65 cannot be rocked, and this will cause rejection of the sheet. As described below, rejection of a sheet causes the tripping of the printing-cylinders The means for rejecting a sheet not in front register comprises a number of ejector rods 80 passing through apertures in the register bar 40 and operated from a shaft 83 adapted to be rocked, against spring action, by a cam .arm 87. The arm 87 is pivoted about the shaft 47 and has a gear sector 86 meshing with a gear 85 fixed on the shaft 83. When the shaft 65 is rocked, the sheet is correctly registered, and a toe 91, Fig. 11, on an arm 92 fixed to the shaft, is aligned with an abutment 93 on the gear sector 86 thus preventing the shaft 83 from rocking to thrust the rods 80 beyond the periphery of the register bar 40. If the sheet S is incorrectly registered, the shaft 65 is not rocked, thus allowing projection of the rods 80 which, as shown in Fig. 11, lift the sheet away from the bar 40. In this case, the grippers 22, 23 are prevented from gripping the sheet, the suction through the holes in the bar 30 is cut off, and the sheet drops off the cylinder. An arm 94, Fig. 2, secured to the shaft 83, rocks a collar 96 on the shaft 14 which, in known manner, trips off the printing-cylinders on the approach of a gripper bar from which a sheet has been rejected.