GB1249010A - Attachment for feeding sheet-like workpieces to a machine - Google Patents

Abstract

1,249,010. Feeding sheets. ADDRESSOGRAPH MULTIGRAPH CORP. 11 Nov., 1969 [13 Nov., 1968], No. 55223/69. Heading B8R. An accessory device for feeding sheet-like workpieces to the work station of a machine, comprises a frame which is attachable to and detachable from the machine and carries a hopper for a stack of workpieces, means for separating the workpieces one by one from the stack and moving them to a position intermediate the stack and the work station, and transport means for moving each workpiece from the intermediate position past the work station to a delivery point, the separating and transport means being driven through a device connectible with and disconnectible from an element of the machine which is moved in synchronism with the machine operation. General arrangement.-The sheet feeding apparatus is carried by a framework which can be positioned on the table top of a machine such as a printing machine 2 where it is secured by clamping means 4, Fig. 2. As applied to a machine wherein address plates are fed one by one to a printing station where an impression is taken from each plate on to a sheet by means of a roller platen 6, the drive to the sheetfeeding device is derived from a lever 8 oscillating in time with the platen-roller movements. The lever 8 is detachably-connected to a cable 112, Figs. 2, 3, attached to a chain 116 passing around a sprocket wheel 118 on a main drive shaft 56 and secured at its free end to a tensioning spring 120. Oscillation of the lever 8 thus causes oscillation of the shaft 56. The shaft 56 drives separator rollers 28, coaxial feed rollers 62, 64, and an endless feed conveyer 90 through one-way clutches, so that rotation of the shaft in one direction rotates the rollers 28 to separate a sheet and move it to the rollers 62, 64, which together with the feed conveyer 90 are stationary during this operation. Similarly, rotation of the shaft 56 in a reverse direction, causes feeding of the sheet by the rollers 62, 64 and conveyer 90 to the printing station, the rollers 28 being stationary. Spring-pressed rollers 72 bear against the rollers 62, 64. The conveyer 90, which co-operates with spring-pressed rollers 106, Figs. 2, 4, and engages one edge only of the sheets, also conveys the previously printed sheet .to a delivery hopper 18. Separation of a sheet occurs during a printing movement of the platen roller 6, and forwarding of a sheet occurs during a non-printing movement. A rising and falling front stop 142 is engaged by the front edge of a sheet to position the sheet for printing. Sheet separators.-The stack of sheets F rests on edge upon a separator blade 26 which is adjusted along a base-plate 24 so that its edge adjacent to the separator rollers 28 is so spaced from the rollers that only one sheet at a time can pass through the gap. A follower 32 guided by rollers or the blade 26. bears by gravity against the stack, and guides 42 act against the top edge of the stack to hold the sheets upright. Front registering stops.-The front stop 142 is carried by a lever 156 pivoted to a block 160, and having a projection 158 caused by the weight of the stop 142 to bear upwardly against a rail on a member 150 pivoted at 152. A cam 144 on the drive shaft 56 actuates a follower 146 connected to the member 150 to pivot the member 150 and raise its rail so that the stop 142 drops into operative position prior to a printing operation and subsequently raises the stop so that the printed sheet can pass to the delivery hopper. The block 160 is adjustable by means of a rack-and-pinion device 178, 166, 164, 162 to vary the position of the front stop. Sensing faulty feed.-A pivoted sensing finger 190, Figs. 3, 4, projects into the path of a sheet adjacent to the rollers 62, 64 and operates a switch S3 in circuit with other switches controlled by timing cams on the shaft 56. The machine is stopped if (a) no sheet is fed forward from the stack to the rollers 62, 64 during rotation of the shaft 56 in one direction, or (b) a sheet present at the rollers 62, 64 is not fed forward to the printing position during rotation of the shaft 56 in the opposite direction. Synchronizing the sheet feed with the machine operation may be necessary, when the feeding device is initially installed on a machine, due to variations in machine dimensions. This is effected automatically by mounting the timing cams, front stop cam 144, and a further cam on the shaft 56 through a slip clutch, the further cam having a projection engaging a fixed stop at correct timing, and the clutch allowing the cams to slip on the shaft to the correct timing positions when the projection engages the stop.