Patent GB-740727-A (GB)
Title: Improvements in intaglio platen printing presses
Inventor: GILLIS EDMUND ANTHONY
IPC: B41F1/40
Filed: 1953-08-18
Abstract: 740,727. Intaglio printing presses. CRONITE CO., Inc. Aug. 18, 1953, No. 22738/53. Class 100(2). Inking apparatus.-In an intaglio platen printing press of the kind in which an engraved printing plate is wiped by movement past a wiping belt passing under a vertically reciprocating pad, separate driving means are provided for advancing the belt, the driving means being controlled by electrical switch means governed by the driving means of the machine. As shown in Fig. 1, the machine comprises a frame 11 having a base 12 and a table 15 with uprights 16, 25. A central driving-shaft 30 carries a pinion 31 meshing with a gear 32 carrying offcentre a roller 38 engaged in a cam,slot 36 in a lever 35 pivoted to the base at 34. The upper end of the lever is connected by a link 40 to the printing plate 41 which is oscillated thereby from a printing position resting on a platen P, past the wiping pad 51 to an inking position under an inking arm 77. A cam 59 rotated by a second gear 44 acts against a follower 58 attached to one arm 57 of a cranked lever 54, the other arm 56 of which is connected to raise and lower the pad 51. A spring-loaded lever 66 oscillated by an eccentric 69 is connected to swing the inking lever 77 which has a roller 78 at the free end adapted to receive ink from a roller 82 running in a reservoir 80 and to carry it to the face of the printing plate in the inking position. The wiping belt 126 passes under pad 51, over scrapers 122, 123 through a washing tank, between scrapers 124, 125, between feeding rollers 92, 93 over idle pulleys 114, 115 and tensioning pulley 127, round pulley 111 and between rollers 101, 103. Rollers 92, 93 and 101, 103 are connected by a chain 109 so that the latter pair rotate more slowly thus ensuring that the belt is well tensioned in the lower part. The shaft 91 of roller 93 is driven by an electric motor 134 through a clutch mechanism shown in Fig. 2. Motor shaft 135 is keyed to a clutch housing 137 inside which is a member 139 keyed to the driven shaft 140. A number of rollers 141 are arranged between the inside surface of housing 137 and flats formed on the member 139 and are controlled in position by a cage member 144 having a toothed control ring 143. The ring 143 is biased by a spring 146, Fig. 3, connected to a boss 145 fixed to the shaft 140, to a position where the rollers jam and lock the shaft 140 to the housing 137. The clutch is released by a pawl 152 adapted to be displaced through a one-way clutch 163 of conventional construction. The motor 134 has two speeds and is controlled through terminals 182, 183, 184, Fig. 7. To ensure that the join 170, Fig. 1, in the belt 126 is passed clear of the pad, there is provided a sensing device comprising a photo-electric cell 172 and perforations 171 in the belt preceding the join. Light shining through the perforations energizes the cell which causes the motor to be connected for fast running, as shown in the circuit of Fig. 7. The photo-electric cell 172 is connected to a relay coil 193 and when energized causes the switch arm 194 to move from the slow-running contact 197 (connected to terminal 183) to the fast-running contact 198 (connected to terminal 184). This relay is self-latching and controls additional switch arms 195, 196. When relay 193 is latched (in the fast running position) and a switch 173, controlled by movement of cam follower 58, Fig. 1, closes, the release coil 201 is energized through switch arm 195. In normal cyclic operation the motor runs continuously at slow speed. As the pad 51 descends to operative position, the switch 173 closes, causing energization of the solenoid 157 by a solenoid 157 into the path of one of the teeth 147 of the ring, this action also preventing further rotation of the shaft 140. Shaft 140 is connected to shaft 91 of the feeding roller 93 through switch arm 187 and disconnection of the clutch 138 so that the belt stops. After the wiping operation the cam 59 moves away from under the roller 58 causing the pad to rise and the switch 173 to open, causing de-energization of the solenoid and allowing the belt feed to continue. A switch 178, Fig. 1, is then actuated by an adjustable cam 175 on shaft 33 and causes relay coil 185 to be energized causing switch arm 187 to leave contact 189 and engage contact 190, thus re-energizing solenoid 157 and stopping the feed. Adjustment of the angular position of the cam 175 varies the length of belt fed in each cycle. Relay 185 remains in a latched closed position until switch 173 again closes. This completes a circuit through switch arm 188 to release coil 186 and allows the control to be taken over by switch 173. In another form the photo-electric cell is replaced by a switch controlled by a sensing arm resting on the upper movable roller 103 so that, when this roller lifts to pass the join, the motor is connected for fast running. Also the cam controlling the switch 178 is formed in two separately adjustable quadrant parts. Specification 672,315 is referred to.