Patent GB-750290-A (GB)
Title: Improvements in or relating to a sheet stacking device for printing machines
IPC: B65H31/32
Filed: 1954-05-10
Abstract: 750,290. Sheet-delivery apparatus. FABER & SCHLEICHER AKT.-GES. May 10, 1954 [May 22, 1953; Dec. 8, 1953], No. 13520/54. Class 100 (1). A stacking device for sheet printing machines comprises an auxiliary receiver or grate consisting of slats or the like arranged temporarily to be inserted over the stack for supporting the sheets delivered by the machine during the exchange of the stacks, and is characterised in that the sheets which are to be deposited on the temporary supporting device are held in the stacking position by gripping devices along their leading edges. In the embodiment shown in Fig. 1, sheets are delivered from grippers 2 on endless chains 4 to additional suction grippers 3 which deposit them on to a stack 11 against a front step 9. When the stack 11 has reached a predetermined height auxiliary gripping devices 12, e.g. suction nozzles, are moved by a link and lever system into the position shown in full lines to receive sheets from the gripper 3 so that, after turning down the front stop 9, a grate 15 may be inserted along guides 17 in order that the pile 11 may be removed. A cam may be arranged on the axis of the chain sprockets 5 which co-operate with a bar on the shaft 13 preventing movement of the grippers 12 except when a sheet is delivered by the gripper 2 to the chains 4, Fig. 8 (not shown). In a further modification, movement of the grippers 12 may be restrained until the grate 15 is moved into its operative position 202 (Fig. 9) so as to rotate a three-armed lever, one arm 220 of which actuates a valve 219 so that suction is applied to the grippers 12, and a second arm 210 of which releases a bell-crank lever 205 from the position shown in dot and dash lines and in which one arm of the lever 205, by bearing against stop 203 on the shaft 13, holds the grippers 12 in the inoperative position. Upon release by the grate-operated three-armed lever, one arm of the bell-crank lever 205 coacts with a cam 209 on the sprocket 5, the cam allowing the lever to move out of engagement with the stop arm 203 at the time of the delivery of a sheet, at which time the grippers 12 may be moved into their operative position. The grate 15, when fully inserted into position above the main stack, actuates a valve 221 to cut off the suction to the grippers 12. In a second embodiment (Fig. 4) the sheets are received by gripper devices 28 when the grate 36a is inserted. The gripper devices 28 are rotatably mounted on a tube 27 including front stops 26a against which the sheets are normally delivered. When the stack 11 is to be removed it is lowered to the position shown and the grate 36a raised in the guides 17 so that its leading edge bears against the grippers 28 to rotate them against the action of a torsion spring into sheet receiving position. In this position suction ports 41 in the grippers are connected by means of bores 39, 40 to the interior of the tube 27 to which suction is applied. In a modification (Fig. 10), rotation of the grippers 109 may be effected by segmental gears mounted on an arm 115, one segment 112 being actuated by movement of the grate 36a into operative position.