Patent GB-972687-A (GB)
Title: Sheet feeding
IPC: G06K13/107
Filed: 1961-07-24
Abstract: 972,687. Feeding sheets. SPERRY RAND CORPORATION. July 24, 1961 [Sept; 2, 1960; May 19, 1961], No. 26768/61. Heading B6B. In apparatus for separating and removing sheets sequentially from a stack, the sheets are picked up by means which is arranged to be stationary at the moment of pick-up, and the sheets are then passed over a fixed vacuum duct which prevents more than one sheet at a time being separated. Pile tables.-As shown in Fig. 1, the sheets are stacked on edge between guides 104, 106 on a baseplate 100 and urged forwardly by a spring 108 towards an adjustable arm 110. In the form shown in Fig. 16, the stack is arranged between a guide 13 and a vacuum chamber 15, and is urged by a spring towards a fixed bar 19 having an adjustable arm 21 mounted thereon. Sheet-separators.-The sheets are separated by a sucker arm 114, Figs. 1 and 11, having a pair of nozzles 144 which move in the closed path shown in Fig. 12 to pick up a sheet, place it in the bight of forwarding belts 116, 118 at a point 156, and then rise and return to the point 154 of pick-up, where the nozzles are temporarily stopped. The spaced nozzles 144, which grip a sheet on either side of the arm 110, are formed on a hollow tube 138 slidable in a tubular extension 146 fixed to a hollow cylinder 148 which is pivoted on the baseplate 100. The cylinder 148 is connected to a vacuum producing means, and the tube 138 is slotted at 150 and sealed at the end, thus suction is not established at the nozzles 144 at the point 156 of transfer of a sheet to the belts 116, 118, since the slot 150 has moved within the extension 146 at that point. The means for moving the nozzles along the path shown in Fig. 12 comprises a pin 153, attached to the tube 138, secured beneath the plate 100 to one end of an arm which is centrally pivoted on a constantlyrotating disc at a point eccentric to the centre of the disc. The adjustable arm 110, against which the sheet stack is urged, regulates the distance between the sucker arm 114 and the front sheet: if the arm holds the front sheet away by a predetermined distance, the sheet is not separated, and this arm may be controlled remotely by a solenoid for starting and stopping the sheet feeding operation. Double-separation of sheets is prevented by a suction chamber 135 having a nozzle or duct on its upper face whereby a second sheet separated by the arm 114 is pulled away from the arm. Compressed air is directed at the side of the stack by a nozzle to fluff up the top sheets, and thus helps to eliminate double-separation. In the modification shown in Fig. 16, the suction chamber 15 prevents double-sheet separation, and forms one side guide for the stack. The wall 72 of the chamber 15 is rounded and slotted at the top, and the edges of the top sheets 11 are held by suction to the top of the chamber in echelon form, as shown. When two sheets are separated together by the suction arm 25, the bottom sheet is pulled away by the suction chamber and is held on the rounded top thereof. Sheet forwarders.-Each sheet separated from the stack is placed between a pair of endless belts 116, 118, Fig. 1, which pass together around pulleys 120, 121, and are supported by pulleys 128-133, and pulleys 122, 125 along a sheet-delivery path. The belt 116 is further supported by a pulley 126, and pulleys 123, 124, 134, and 127 support the belt 118. The belts travel faster than the speed of the sucker arm 114, so that the sheets are pulled away from the arm without any bending or crumpling.