GB938212A - Improvements in or relating to sheet-feeding apparatus - Google Patents

Abstract

938,212. Feeding sheets. CROSFIELD ELECTRONICS Ltd. Jan. 10, 1962 [Jan. 12, 1961], No. 1342/61. Class 100 (1). Sheet-separators.-Sheets, such as cheques of assorted sizes, are stacked on edge on the base 10, Fig. 1, of a holder and urged against the front plate 11 adjacent an outlet opening 13, and are separated sequentially and fed through the outlet 13 by means such as a rotating suction wheel 19 which first imparts a curvature to each sheet so that it can pass an adjustable stop means 17 which protrudes into the outlet. The trailing edge of each sheet is retained by an intermittently operated suction device which, when operative, prevents the removal of the sheet by the wheel 19; this device comprises a vertical spindle 27 in a block 26 which is slotted at 28, a recess 29 in the spindle which communicates with a vacuum source, and a further slot 30 in the spindle which leads to atmosphere. The spindle 27 is driven periodically by belt and pulley means, and the sheets are gripped when the recess 29 registers with the slot 28. As shown, the front plate 11 has an open slot 14 opposite the wheel 19 to cause double curvature of the front sheet, but the slot may be a closed one. The wheel 19, which is driven by belt and pulley means, is slotted at 20 to communicate with a hollow shaft connected to a vacuum source. The stop member 17 is adjustable by screw means along the side wall 12, and may have an air passage therein which leads to the tip thereof, whereby compressed air from a pipe 37, Fig. 4, can assist sheet separation. In cases where the sheets have coded matter thereon, a magnetic or optical reading head may be arranged on the wall 11 in the position where the registering roller 70 is shown in Fig. 5, in which case the roller is not fitted. In a modification, where the sheets are too stiff to be curved by a single suction wheel, two suction wheels 75, 76, Fig. 7, are arranged to rotate on oblique shafts 77, 78, respectively, and these engage a sheet before they reach their minimum separation to draw the two engaged portions of the sheet together. The suction wheel or wheels can be dispensed with, and a pair of twisted belts 80, 81, Fig. 8, are used. The belts are perforated and mounted on sets of pulleys 82, 83, 84 and 85, 86, 87. The pulleys 83, 86 are mounted on the same shaft which is driven, and the pulleys 82, 85 are hollow and connected to a vacuum source so that they can apply suction to spaced portions of a sheet through the perforated belts, and curve the sheet to permit it to pass the stop 17. Registering sheets; pile supports.-To ensure that each sheet before separation rests accurately on the base 10 of the sheet holder, a drive rubber &c. roller 70, Fig. 5, may be arranged in a slot in the front wall 11. The stack of sheets is urged along the base 10 against the wall 11 by pegs on a first pair of endless chains driven by a motor through a slipping clutch. The stack is replenished by placing a second stack behind the first stack, and pegs on a second pair of endless chains, which are shorter than the first chains and are also driven by the same motor and another slipping clutch, feed the second stack into contact with the first one, and both stacks are urged forward. A selector is arranged to engage one set of pegs to stop the motion of that chain while allowing the other chain to feed a stack. When the last sheet of a stack is separated, the pegs on the chain pass through slots in the front plate 11 of the holder. The pressure exerted on a stack by the pegs on the feed chains may be predetermined and automatically controlled by means comprising a lever 65, Fig. 4, pivoted at 66, which carries a portion of the front plate 11 at one end, and is arranged in a switch device 67 at the other end. A motor drives selectively either of the two endless chains through two separate clutches each operated by an air cylinder. When the pressure exerted on the stack is excessive, the lever 65 is pushed towards the suction wheel 19, against the action of a spring 68, and the switch 67 is operated to control the air cylinder of the appropriate clutch to allow the latter to slip. When the pressure exerted is too low, the spring 68 will operate the switch 67 in the opposite direction to cause the clutch to exert a greater force on the chain. Reference has been directed by the Comptroller to Specification 743,387.