Patent GB-468587-A (GB)
Title: Improvements in or relating to stencilling machines
IPC: B41L21/02
Filed: 1936-09-11
Abstract: 468,587. Rotary duplicators. ROY, A. A. Sept. 11, 1936, No. 24841. [Classes 100 (i) and 100 (ii)] Feeding sheets ; tripping-arrangements; counting-apparatus.-In a rotary stencilling-machine, the sheets are fed by means of continuously-rotating members provided with segmental blocks of rubber or the like which drag forwards the bottom sheet from a pile and pass it through a slit between the pile-table and a front abutment. The machine may be provided with means controlled by counting-apparatus for throwing out the sheetfeed when a predetermined number of sheets has been printed, means for preventing operation of an impression-roller when a sheet is not fed, and means for adjusting the impressionperiod to provide for skipping parts of the stencil. In the machine shown in Figs. 2, 6 and 13, stencil-carrying bands 9 pass around a drum 7 provided with feed-pins 8, and a roller 10 supported by spring-urged arms 11. The drum-shaft 6 is provided with a pinion 5 which engages a pinion 4 on a shaft 2 driven by a crank or motor. The sheets 31 are stacked on a table 27 provided at the sides and rear with adjustable plates 28, and at the front with an abutment 32 which provides a slot for the bottom sheet. The table is provided also with anti-friction rollers 39. The sheets are fed by means of rollers 33 secured to a shaft 34 and provided with rubber segments 35 arranged to pass through slots 36 in the table. To prevent the feeding of more than one sheet at a time, the side plates 28 are provided with rubber facings 40, these being preferably thicker at the bottom than the top. The shaft 34 is driven from the shaft 2 by means of a chain 41<a> which passes over a sprocket-wheel 41 connected to the shaft 34, and a sprocket-wheel 18 which is loose on the shaft 2 and has a tooth 17 cooperating with a pawl 14 pivoted on the pinion 4. The sprocket-wheel 41 is adjustably connected to the shaft 34 by means of a pin 88 which engages notches in the sprocket-wheel and is carried by a retractable knob 94. The sheet-feeding device can be uncoupled by setting a finger-lever in such a position that a stop 21 connected thereto comes into the path of the pawl 14. The sheet-feeding device can also be uncoupled by means, described below, under control of a counter. An impression-roller 38 is mounted in an arm 53 secured to a shaft 54, and in another arm which is loose on the shaft and is held by a strong spring in contact with an adjusting-screw mounted in a finger on the shaft. The arm 53 engages an adjustable actuating-spring 55 and is provided with a roller 52 co-operating with a two-part cam 45, 46 on a shaft 47 which is connected by pinions 44, 43, 42 to the shaft 34. The cam-part 46 is secured to the shaft 47, and the pinion 44 is loose on the shaft and has secured thereto the cam-part 45. A finger 49 on the cam-part 45 can be engaged with any one of a series of holes in the cam-part 46 to permit of relative adjustment of the cam-parts. When a sheet has been fed under the drum 7, the cam-part 46 releases the roller 52, and the impression-roller is raised by the spring 55 and subsequently depressed by the cam-part 45. The impressionperiod can be adjusted, to permit of skipping selected parts of the stencil, by adjustment of the cam-parts 45, 46 and the sprocket-wheel 41. To permit of fine adjustment of the impressionperiod, the pinion 43 is mounted in a vertically movable support 95 which is connected by a bell-crank 97 and link 99 to an adjusting-screw 100. An adjustment-indicator is carried by a shaft 103 in connection with the link 99. If a sheet is not fed, the impression-roller is prevented from engaging the stencil by means of a pivoted, spring-urged sheet-feeler having a finger 64 adapted to pass through a slot 65, and fingers 67, 69 co-operating with a hook 68 and a projection 70 on the arm 53. When the arm is raised, the feeler is swung upwards and if a sheet has not been fed, the finger 64 passes through the slot 65, and the finger 69 engages the projection 70 and prevents effective operation of the impression-roller. Means for automatically uncoupling the sheet-feeding device when a predetermined number of sheets has been printed comprises a counter 25 having the numbers arranged in reversed order. The final counting-wheel has a finger 26 for engaging the pawl 14, and the actuating-pawl 78 of the counter is connected by a link 76, lever 74, and link 71 to the arm 53. The counter is set to show the number of sheets, and when the sheets have been printed, the finger 20 releases the pawl 14 and the sheet-feeding device is uncoupled. The link 71 operates also an ordinary counter 72. To permit of silencing the counter 25, the pivot 75 of the lever 74 can be pulled outwards to disengage a slot in the lever from a pin 73 on the link 71. The pivot-head is provided with pins which normally engage holes in the frame. After the pivot has been pulled outwards, it is turned slightly and is held in displaced position by means of the pins. A sheet-ejecting roller 57, co-operating with a pressure roller 60, is driven by a chain 58.