Patent GB-664276-A (GB)
Title: Sheet-feeding mechanism
IPC: B41F21/05
Filed: 1949-03-24
Abstract: 664,276. Feeding sheets. MIEHLE PRINTING PRESS & MANUFACTURING CO. March 24, 1949 [Aug. 3, 1948] , No. 8013/49. Class 100 (i). A sheet-feeding mechanism wherein oscillating grippers transfer registered sheets from a position of rest on a feed table to the grippers of a rotating impression cylinder, the oscillating grippers being actuated by cams to move in a substantially parabolic path, tripping- mechanism is provided for rendering the sheet-feeding mechanism inoperative when a sheet is not registered. Both automatic and manual means can control the trip- . ping-mechanism. Sheet-carriers. As shown, a set of sheettransfer grippers 33 is secured on a rockable shaft 15 which is mounted in arms 14 clamped to a shaft 10 adapted to be oscillated to move the shaft 15 in a circular path, and the shaft 15 is rocked by a cam in the arms 14 whereby the grippers 33 move in a parabolic path, as indicated in Fig. 6. The shaft 10 is journalled at each end in side stands 11, and is rocked by a clutch' which is itself rocked by means of a toothed sector thereon engaging a pivoted toothed sector 22 provided with two rollers each engaging a cam on a drive shaft 31. The gripper shaft 15 has secured thereto a lever 37 carrying a roller 38 engaging a fixed cam 40 adapted to move the gripper fingers 34, and a gripper pad bar 42 having pads 43 thereon is similarly rocked about the shaft 15 by a lever 44 having a roller 38A (not shown) engaging a fixed cam 45. The gripper fingers 34 are opened and closed by a cam 57 carried by a lever 58 pivoted at 59 and rocked by a cam 61 on the shaft 31. During the transfer of a sheet from a feedboard 51, the fingers 34 and pads 43 follow a substantially parabolic path, approximately tangential to the board 51, and transfer the sheet tangentially to an impression cylinder 62. The various rollers engaging cams are held thereon by spring pressure, and are mounted on eccentric studs whereby they can be adjusted. The clutch whereby the transfer shaft 10 is oscillated comprises a drive disc 16, Figs. 1 and 8, mounted on the shaft and carrying a toothed sector 17 (not shown), a slotted tube 19, a compression spring 20, and a latch 21 fixed to the tube 19 which is slidable through an opening in the shaft 10, and can be raised or lowered to either engage with or disengage from the disc 16. Tripping-mechanism. When a sheet is registered accurately against cam-actuated front stops 52 on the feed-board 51, Fig. 6, a known form of sheet detector depresses a pivoted lever 69, Fig. 8, to bring its opposite end 71 into the path of a lever 73 to prevent the latter from being actuated by a cam 76. If a sheet is out of register, the lever 73 is allowed to follow the cam 76, a shaft 74 and a lever 77 secured thereto are rocked, and a projection 78 engages a plate 82 secured to the clutch latch 21 whereby the tube 19 is raised. The latch 21 is raised out of a V-shaped slot 83 in the drive disc 16 and rides on the inside surface thereof, and the disc cannot therefore drive the transfer shaft 10 carrying the sheet grippers. A safety plate 86 having two openings 87, 88 thereon partly surrounds the disc 16 so that the latter can be disengaged in two positions only, one at 87 by the automatic means just described, and the other at 88 by a manual tripping means described below. Manual tripping of the sheet transfer mechanism can be effected by manually rotating a central shaft 96 provided with an end projection adapted to engage a slot in the tube 19 and raise the latter so that the latch 21 is withdrawn within the disc 16 and so prevents oscillation of the transfer shaft 10 by the disc. A disc and spring-pressed pin arrangement on one end of the shaft 96 facilitates rotation and setting of the shaft. Grippers 63, Fig. 6, in the impression cylinder are opened and closed by means incorporated in the sheet transfer mechanism. The lever 58, controlling the movement of the cam 57 which opens and closes the transfer grippers, has a further cam 100, Fig. 1, thereon adapted to move into and out of the path of a lever which opens and closes the grippers 63 to receive a sheet from the transfer grippers 34, 43. Further, the grippers 63 are opened to release a printed sheet to a known form of delivery mechanism by the lever 58, the latter being connected at 101 by a link to a toothed segment 102 adapted to actuate a mating segment 104 on which is a bar 106 connected to a cam 107 pivoted at 108. This cam 107 is thus raised or lowered to control the cylinder grippers 63 for delivery of a sheet. Sheets can be retarded, substantially as described in Specification 417,301, before contacting the front stops 52, by modifying the contour of the cam 57 which controls the opening and closing of the gripper fingers 34, and providing slow-down fingers 109 (not shown) which intercept the sheet and decelerate it, the pads 43 preventing curling of the front edge of the sheet during this retardation, and the fingers 34 remaining open until the sheet is registered.