Patent GB-543973-A (GB)
Title: Duplicating machine
IPC: B41L11/00
Filed: 1940-06-18
Abstract: 543,973. Rotary duplicating machines. DITTO, Inc. June 18, 1940, No. 10527. Convention date, June 20, 1939. [Class 100 (ii)] In a rotary duplicating machine, the master sheet is fed step by step over the surface of the drum by means of a feed roller arranged within the drum so that the successive copy sheets may receive impressions from different sections, e.g. lines of the master sheet. In one form, Figs. 4 and 5, the master sheet 68 is gripped at its leading edge by a clamp 67 and passes into the drum, through a gap 58, in loop form between a feed roller 59 and co-operating pressure roller 63 and the copy sheets are fed between the drum and co-operating pressure roller so that the bottom or rear line of the copy sheet receives an impression from the line of matter on the sheet 68 adjacent the edge of the gap 58 remote from the clamp 67. Normally, between each impression, the sheet 68 is advanced one line width by the rollers 59, 63 by means of a ratchet wheel 71 on the shaft 60 of the rollers 59 and a pawl 75 pivoted on a slide 72 actuated by a cam 78 on the machine frame. The cam 78 is carried by pins slidable in the frame so that the cam can be withdrawn from the path of movement of the cam follower 86 on the slide, if it is desired to repeat the same impression on two or more copy sheets. The pressure roller 63 is carried by a yoke 64 bridging a pair of arms 62 pivoted to the drum one of which carries a roller 81 which co-operates with a cam 77 mounted on the machine frame similarly to the cam 78. The cam 77 also co-operates with a roller 82 on an arm 83 which engages the inner end of an arm 69 slidably mounted in the drum and carrying the master sheet clamp 67. To insert a master sheet, the cam 77 is moved inwardly into the path of the rollers 81, 82 and the drum is turned into the position shown in Fig. 4 so that the roller 63 is raised clear of the gap 58 and the clamp 67 is opened. After insertion of the master sheet, the drum is turned so that first, the roller 82 moves from the cam to allow the clamps 67 to be closed by a spring 70 and then the roller 81 moves clear of the cam to allow a spring 65 to move the roller 63 into contact with the roller 59 as shown in Fig. 5. The cam 77 is then withdrawn clear of the rollers 81, 82. In a modification, Figs. 8 and 12, the master sheet is clamped by grippers 96 on a rock shaft 97 provided with an arm 100 carrying a roller 101 which cooperates with a cam 103 pivoted at 104 to the machine frame. An adjacent cam 123 also pivoted at 104 co-operates with a roller 122 on an arm 121 fixed to a shaft 120 carrying a pair of arms 119, Fig. 12 which bear at their free ends against slide bars 115 carrying the pressure roller 114 which co-operates with the master sheet feed roller 112. A hand lever 109 pivoted about the shaft 89 of the drum, carries a roller 110 engaging the lower edges of the cams 103, 123 and in the position of the lever 109 shown in Fig. 8, these cams are lowered clear of the path of the rollers 101, 122, the grippers 96 are held closed by a spring 102 attached to the arm 100 and the roller 114 is held in engagement with the roller 112 by a spring 118, Fig. 12. To insert a master sheet, the lever 109 is moved to the left in Fig. 8, so that the cams 103, 123 are raised into the path of the rollers'101, 122, to cause opening of the grippers and outward movement of the roller 114 as the drum is brought to the position shown. The step by step advance of the master sheet is effected by a gear wheel 126 fixed to its shaft 113, and a pawl 131 carried by an arm 130 freely mounted on the shaft 113. A cam lever 133 pivoted to the drum carries a lug 135 engaging the arm 130 and as the drum rotates the lever 133 engages a plate 136 on the machine frame, thereby giving a feed movement to the arm 130 against the action of a return spring 132. The plate 136 is slidably mounted and connected by linkage 139, 141, 142 to a hand lever 144 by which the plate may be withdrawn from the path of the lever 133 if repeat printing is desired. A detent roller 128 holds the gear wheel 126 against return movement. A sheet metal guard plate 145, Fig. 12, held on the drum by clips 146 may be provided to prevent contact of the non-printing portion of the master sheet with the impression roller. If the machine is to be used for printing, at one impression, the whole of the matter on the master sheet, a sheet of stout metal foil may be arranged beneath the master sheet to bridge the gap in the drum adjacent to the roller 114.