GB929540A - Improvements in or relating to machines for stacking paper sheets - Google Patents

Abstract

929,540. Stacking sheets. I. DALE, and G. A. MEAD. Nov. 20, 1961, No. 41376/61. Class 100 (1). A device for stacking sheets of paper comprises a vertical back-stop 14, a feed-plate 42 across which sheets are successively delivered against the back stop, a movable table 15 normally positioned to receive sheets after they have struck the back stop, a number of fingers 40 mounted beneath the feed-plate, a number of shoes 26 movably mounted on the back stop, means for extending the fingers and shoes from normally retracted positions across the adjacent top edges of a continuously forming stack to divide the lower portion from the upper portion as it forms, and means for moving the table so as to convey the lower portion of the divided stack to an unloading station and to return the table to its normal position after unloading. The table 15, Fig. 10, has a top 50 connected to a base 54 at each side by a pair of crossed and pivotally jointed levers 51, 52. The base 54 has wheels 55 whereby the table can travel along a trackway 56 in the machine frame when driven by a motor 75. A fluid-actuated piston-andcylinder arrangement 67 is mounted on a crossshaft 53 which forms the pivot of the two pairs of levers 51, 52. The piston-rod is connected to a cross-head 67h carrying rollers 68 which engage the levers 51, 52 so that horizontal movement of the piston-rod effects raising and lowering of the table top 50. Fluid under pressure is metered to the piston and cylinder arrangement 67 under control of a sheet counter so that the top 50 is lowered continuously as the stack of sheets builds up on it. A multiplicity of small valves is incorporated in the upper surface of the table top 50 which valves are opened by the weight of a stack of sheets resting thereon so as to permit the escape of air under pressure from a chamber beneath the surface and facilitate sliding removal of the stock from the table. The shoes 26 are movable short distances in vertical and horizontal directions by means of a pneumatic cylinder and a solenoid respectively. Normally they are retracted, so that their forward edges are flush with the working face of the end stop 14, and in a raised position; the fingers 40 are also normally in a retracted position. After a predetermined number of sheets 10, detected by the abovementioned sheet counter, has been fed by a belt conveyer 11 and feed rollers 12, 13 on to the table top the fingers 40 and shoes 26 are moved inwards towards each other and the latter are lowered into engagement with the top of the pile. Sheets continue to be fed on top of the fingers and shoes and the table 15 is moved to the right, as seen in Fig. 2, carrying the counted batch 16 of sheets with it. As the table moves a plurality of belts 70 is drawn across the bottom of the stacking area to support the sheets as they are deposited across the extended fingers and shoes. The belts 70 are secured at one end beneath the plate 42 and at the other end are attached under spring tension to a cross-beam 74x; the belts also pass round rollers 72, 74 which are mounted on and travel with the table 15. When the table 15 reaches the right-hand end of its travel it stops and the batch 16 is pushed laterally off it and on to a stationary table by a motor-actuated pusher-bar 88. Thereafter the table is moved back and raised to its original position, the fingers 40 and shoes 26 are retracted and the new stack continues to build up on the table top 50. The device is controlled automatically by means of a number of limit switches actuated by the moving parts of the device.