Patent GB-478423-A (GB)
Title: Duplicating machine
IPC: B41L21/02
Filed: 1936-04-16
Abstract: 478,423. Stencilling-apparatus; feeding sheets. NIGRA, F. April 16, 1936, No. 10940. [Classes 100 (i) and 100 (ii)] A rotary stencil duplicator is constructed with a printing-cylinder 3, Fig. 9, with which coacts intermittently an impression roller 18 mounted in arms 20 pivoted about a rockshaft 21 and acted upon by tension springs 23, tending to press the roller 18 into contact with the cylinder 3, the roller 18 being allowed to contact only if a sheet is fed from the pile 14 at the correct time. The sheets are advanced from the pile by means of a sectional feed-roller 52, Figs. 9 and 21, on a shaft 53 carried by arms 54 on a rock-shaft 44, a common actuating means being provided for controlling the mutual coaction of the printing and impression cylinders and of the feed rollers, the said mutual coactions alternating one with the other. The pile 14 is kept at a constant level by means of spring mechanism controlled by an escapement, this level being such that the top sheet only is higher than a front gauge 56 arranged at the centre of the pile. Other devices for preventing double feed by the rollers 53 comprise a weight member 171, Fig. 6, slidably mounted in a guideway in one of the side walls 167 for restraining the sides of the pile and provided with an oblique edge 172 engaging the top sheet of the pile. The other edge of the pile is engaged by the sharp edge 170 of a member 169 mounted in a guideway in the other side wall 167. The pile is pressed upwards by arms 103, Fig. 24, on shafts 101, 102, rollers 105 on the arms engaging horizontal guides attached to the pile table 15. The shafts 101, 102 tend to rotate under the action of springs 111 acting on arms 109 on the shafts, and the upward movement of the table is controlled by an escapement wheel 121, which is geared to a rack 113 pivoted to an arm 109. An escapement pawl 126 permits movement of the escapement except when a stop 131 on a spring-controlled shaft 134 prevents movement of the pawl. The shaft 134 is fitted with an arm 136 which is adapted to be acted upon by an adjustable stop 141, Fig. 22, which moves with the rock-shaft 55 of the feed roller 52. The stop 141 releases the escapement mechanism when the roller 52 descends owing to the feeding off of a sheet, and the springs 111 then cause a raising of the table. The automatic raising of the table by the spring and escapement mechanism is cut off when only a few sheets are left in the pile by means of a stop 165 on the table which engages a spring-pressed pin 164 on a lever 162 and raises this into the path of an arm 144 on the rock - shaft 55. The stop 141 is thus prevented from releasing the escapement mechanism automatically. The last sheets may be fed off by hand-operation of the lever 162. The separated sheet is fed between an upper cylindrical spring-pressed sectional roller 16, Figs. 9 and 21, and a lower segmental sectional roller 17 on a fixed axis 34, and is arrested by stops 39 on a fixed guide 36 which is slotted to permit of the coaction of the sectional rollers 16, 17 therethrough. The sheet is buckled slightly while in contact with the stops 39 and then the roller 53 is raised to permit the separated sheet to straighten out. As the raised parts of the segmental roller 17 come into action to' feed the sheet over the guide 36, an oscillating guide member 43 is actuated by a cam on the shaft of the rollers 17 to raise the sheet above the stops 39, and other guides 48 limit the extent to which the sheets are raised. The rollers 16, 17 then feed the sheet over the guide 36 and between the rollers 3, 18, and if a sheet is in position the rollers 3, 18 are pressed together to effect the printing, but if a sheet is not present, the roller 18 is held in the position shown in Fig. 9. The arms 20 in which the roller 18 is mounted are normally oscillated by means of lever arms 24 on the rock-shaft 21, which is oscillated by means of a cam 70, Fig. 17, on the main shaft of the printing-cylinder 3. The cam 70 depresses a spring-pressed member 68 connected to a lever arm 69 on the shaft 21. A cross-bar 22, Fig. 9, connecting the arms 20 acts in conjunction with a pair of spring-pressed stop members 58 to control the movement of the arms 20 which are freely mounted on the shaft 21. If the stop members 58 are allowed to assume the position shown in Fig. 9, the bar 22 engages in a recess in the members, and the roller 18 is held out of printing position. Normally, the stop members 58 are held by a detent 62 controlled by the upward movement of feelers 65, Fig. 21, which are raised into contact with the sheet, and the cross-bar 22 is allowed to descend far enough to raise the roller 18 to printing position. If a sheet is absent, the feelers rise under spring action and the stop members 58 prevent the roller 18 from acting. The shaft 34 of the lower feed rollers 17 is driven by an oscillating segmental gear 73, Fig. 17, which is operated through an adjustable pin-and-slot connection from the member 68 that operates the shaft 21. The gear 73 engages a gear 78 which drives the shaft 34 through a one-way clutch. The shaft 55, Figs. 9 and 21, which carries the lever arms 54 of the separating rollers 52, is oscillated by a cam 149, Fig. 17, and adjustable lever-andlink mechanism 148, 150, 151, 147, 146. The shaft 53 of the feed-rollers 52 is driven by a pinion 91 and a reciprocating rack 90 having a yielding connection with the oscillating segment 73. The feed-rollers may be put out of action by means of a stop-lever 153 controlled by a stop 154 which can be set in three positions permitting (1) normal feed; (2) stopping of the feed-rollers 52 ; and (3) stopping also the actuation of the segment 73, this being effected by a stop lever 159 actuated by a pin on the link 147 which is raised by the lever 153. The cam 148 is mounted so that it can be adjusted circumferentially relatively to the axis of the cylinder 3, and the cam 70 is formed of two similar parts which can be set so that the profiles register, or may be set out of register. In the latter case, the stencil may contain two or more distinct sets of reading matter for placement on a like number of sets of sheet, each sheet being run through separately and the cams adjusted as required. The shaft of the printing cylinder 3 is provided with a belt pulley for power drive, and with a gear 12 engaged with a gear 11, Fig. 17, on a parallel shaft provided with a hand crank for alternative manual operation ; a pawl 235 can be adjusted by means of a cam 238 provided with a handle 240 into or out of locking engagement with the gear 12. A counter is connected by a link member with an arm 20 of the rockshaft 21. As the sheets are delivered inset sheets are inserted between successive sheets as described in Specification 478,478.