GB1462128A - Sheet stacking machine - Google Patents

Abstract

1462128 Delivering sheets; guiding elevating platforms I D Inc 12 Aug 1974 [15 Aug 1973] 35459/74 Headings B8R and B8L A sheet stacker comprises a table 18, Fig. 2, vertically movable in a frame 10, the upper surface of the table being formed of rotatable rollers 24, Figs. 1 and 2. A self-levelling device for the table comprises a torsion bar 70 at either side of the table, each bar carrying sprockets 72, 74 at each end. A chain 76 is secured to the frame at 78 above the table, passes under one sprocket 72 and over another sprocket 72, and is secured to the frame at 80 below the table. A chain 82 is similarly but oppositely arranged in engagement with sprockets 74, being secured to the frame at 84, 86. Similar chains 76, 82 are arranged at the other end of the table. Raising or lowering of any corner of the table thereby results in raising or lowering of the other three corners. The table is raised and lowered as a whole by pistons 36 in hydraulic cylinders 38, each piston actuating a chain 28 secured at its lower end 30 to the table and at its upper end to the frame and passing over a sprocket 34 attached to the piston. There are two chains 28, one at each of two diagonally opposite corners of the table. The pistons are actuated by a three-way valve 42, which enables the table to be raised, lowered or held stationary, the fluid being supplied by a low-capacity hydraulic pump 48 for slow movement or by pumps 48 and 50 for rapid movement. The rollers 24 are driven by a chain 64 passing under sprockets 26 on the end of every second roller and over intermediate idler sprockets 26, and also passing over a fixedly mounted sprocket 68 and a sprocket 66 mounted on the table, and the chain is driven by an hydraulic motor 62 controlled by a solenoid valve 60, the fluid being supplied by the pumps 48 or 48, 50 for slow or rapid motion. The pumps are driven by an electric motor 51. The valve 42, pumps 48, 50 and valve 60 are actuated by an electrical control circuit 44. In operation, with the table in its upper position, sheets delivered from a corrugating machine by a belt 88 assisted by an idler roller 102 engage a stop member 94 and form a stack 92 on the table. When the stack reaches a predetermined height, the light path to a photo-electric detector 96 is blocked and the table is lowered until the path is free, thus moving down intermittently until it engages a microswitch 110, whereupon a solenoid 108 is energized to lower a gate 104 to prevent entry of further sheets, while the rollers 24 are rotated first slowly and then rapidly to eject the stack. After a delay, the table is raised rapidly until it strikes a microswitch 112 and then slowly until it strikes the stop 94, whereafter the gate is opened.