Patent GB-494864-A (GB)
Title: Duplicating machine
IPC: B41L9/10
Filed: 1937-12-17
Abstract: 494,864. Hectograph duplicators. DITTO, Inc. Dec. 17, 1937, No. 34957. Convention date, April 1. [Class 100 (ii)] Relates to duplicating-machines of the type comprising a duplicating-surface, such as a gelatine band 35, stretched over a flat support 38, a device, such as a roller 40, for pressing copy sheets against the band, and a member, such as a lever 46, for moving the roller into and out of operative position, and consists in providing means responsive to movement of the lever, for advancing the roller step-by-step over the band whereby an impression of part of the original is taken on one copy sheet and an impression of another part is taken on another copy sheet. The roller 40 is mounted in arms 43 pivoted at 44 to a reciprocatable carriage comprising an upper part 49 detachably connected by latches 53 to a lower part 52 having longitudinal bars engaging bearings inside tubular frame members 30. A copy sheet 64 is placed on a tray 63 and is passed between the roller 40 and a feed roller 41 to a margin stop 65. On rocking the lever 46 to the right, the stop is moved away, and the roller 46 presses the sheet on to the band 35. During the return movement of the lever 46, the carriage 49, 52 moves to the right a distance corresponding to the pitch of teeth 98 on a rack 95 and to the line spacing of the original, so that the second line is printed on the second sheet. This step-by-step movement is provided by means of two pawls 146, 156 co-operating with the rack 95, the former having a bevelled end 147 so as to allow movement of the carriage to the right but prevent reverse movement, and the latter locking the carriage against movement in both directions. The pawl 146 is pivoted at 145 to the lower end of a lever 137 pivoted to the carriage at 112 and provided with stop lugs 139, 140. Levers 111 rocked about the same pivot 112 by a bar 106 actuated by a projection 105 on the lever 46 engage loosely between the lugs and carry a pawl 115 engaging a ratchet 113 towards which a pawl 130 is pressed. The pawl 130 engages a projecting part 155 of the pawl 156. On depressing the lever 46 for printing, the bar 106 falls, and the levers 111 engage the lug 140 thus moving the pawl 147 to the right to the next notch. On raising the lever after an impression, the levers 111 first advance the ratchet 113 whereby the pawl 130 in passing over a tooth is pushed downwardly and raises the pawl 156 out of the rack, and then engage the lug 139 whereupon the pawl 145 provides a fulcrum so that the carriage is moved to the right. The pawl 130 then rises into the next tooth and releases the pawl 156 which drops into the next notch in the rack. A pivoted arm 150 is provided which may be swung clockwise manually at any time to release both pawls 146, 156 from the rack 95 and allow movement of the carriage and which engages an adjustable stop at the end of the movement to the right to allow return of the carriage, a stop 80 being provided at the opposite end to return the arm to normal position.. The stop 80 is turned into an inoperative position when applying the original to the band. In a modification wherein the carriage is advanced at alternate impressions so that the same line is copied on two successive sheets, a second ratchet fixed to the ratchet 113 has half as many teeth and acts on two pawls, one for operating the pawl 156 and the other engaging the lever 137 to move the carriage forward. A further modification for printing the same impression on three sheets comprises two additional ratchets, each ratchet having one third as many teeth as the ratchet 113, and one operating the pawl 156 and the other the lever 137. Specification 424,027 is referred to.