GB1019091A - Dispenser for film and other sheets - Google Patents

Abstract

1,019,091. Feeding sheets. D. W. LINDSAY. April 25, 1962 [April 26, 1961], No. 15030/61. Heading B6B. Apparatus for separating sheets sequentially from the bottom of a stack comprises a support 2 for the stack, an adjustable stack outlet which only allows the bottom sheet to pass, a driven roller 15 arranged beneath the bottom sheet of the stack but not in contact therewith, a roller or other means arranged to be oscillated vertically to depress the stack so that the bottom sheet can be separated frictionally by the roller 15 through the stack outlet, and sheet-forwarding rollers 27, 28 located on the exit side of the stack outlet. The apparatus is particularly designed for dispensing exposed radiographic film sheets to a processing machine, and comprises a chamber 1 housing a sheet-stack support 2, 4 which is inclined at 2, horizontal at 4, and slotted at 3. Above the edge of the part 4 is a narrow inclined blade 8 defining a gap through which only one sheet can pass, the blade being secured to a flexible cross-bar 9 which has a spring-and-screw adjustment connection with a rigid cross-bar 11, whereby the blade can be adjusted vertically. The driven roller 15 is mounted on a fixed axis beneath the slot 3, and a heavy copper roller 16 with a resilient covering 17 is arranged above the roller 15 in arms 18 which are pivoted at 19. Normally, the roller 16 is held away from the roller 15 by chains 20 which connect the pivoted arms 18 with levers 21 which are swung about pivots 26 by springs 22; but when a solenoid 23 is excited, a tie 25 between the levers 21 and the solenoid armature 24 is arranged to lower the roller 16 to press the sheets on to the driven roller 15. Each sheet is forwarded by the feed rollers 27, 28 on to an inclined shoot, and descends under gravity to a further pair of feed rollers which feed it to a processer. The rollers 15, 27 and 28 are driven by chains from a motor. The roller 28 is mounted for limited vertical displacement on a pivoted lever, and can actuate either of two switches S<SP>1</SP>, S<SP>2</SP>, Fig. 6 (not shown); switch S<SP>1</SP> is closed when only one sheet passes between the rollers 27, 28, and when two superimposed sheets pass between the rollers, switch S<SP>2</SP> is closed to stop the apparatus. A third switch S<SP>3</SP> is opened when there is no sheet on the support 2 to depress the contact arm 43, but only stops the apparatus when the sheet passes the rollers 27, 28 so that the switch S<SP>1</SP> is also opened. A further switch S<SP>4</SP> beyond the rollers 27, 28 is opened by a sheet on the shoot to stop the apparatus separating a further sheet until the first sheet has passed to the processer. With the switch S<SP>3</SP> closed by sheets on the support 2, the circuit to the motor M is through the switch S<SP>1</SP>, and through the switch S<SP>1</SP> to a delay relay A/1 which delays the energization of the solenoid 23 through a relay switch a<SP>1</SP> for one second. Then the roller 16 is lowered to cause a sheet to be driven to the nip of the rollers 27, 28, where the roller 28 is lifted to open switch S<SP>1</SP> and cause the roller 16 to be raised. The switch S<SP>1</SP> now serves the motor M, so that the sheet is fed forward by the rollers 27, 28 even if switch S<SP>3</SP> is open. If a sheet is not advanced to the rollers 27, 28, a delay switch b<SP>1</SP> is closed to operate a warning device W. A pilot light PL is switched on when the processer is free to accept a further sheet. Sheets requiring priority treatment can be fed by hand into the processor by first operating a blocking switch S<SP>5</SP>. In a modification, the front part 4 of the sheet support 2 can be inclined to guide the sheets upwardly through the gap in the stack outlet.