Patent GB-272599-A (GB)
Title: Improvements in and relating to the manufacture of printing plates
IPC: B41D3/00
Filed: 1926-03-16
Abstract: 272,599. Marks, E. C. R., (Wood Newspaper Machinery Corporation). March 16, 1926. Stereotype, casting and finishing.-A stereotype casting-machine is provided with a back adapted to hold a plurality of matrices for interchange into casting position. The invention is described as applied to a machine in which the back is provided with two concave matrix-supporting surfaces each adapted to hold a doublewidth matrix or one or two single-width matrices. The back is movable to and from a rotating core as usual for casting, and in addition can be withdrawn further from the core and rotated for interchange of matrix. Automatic devices are provided for rotating the core, withdrawing the back in the ordinary way, operating the pump, and trimming the plate or plates, and manually-controlled devices for further withdrawing and rotating the back. Core-operating mechanism. The water-cooled core 13, Figs. 3 and 17, is rotatably carried on a shaft 12 mounted on the base-plate 10 and is adapted to be rotated a half-turn automatically after each cast. A cam-shaft 125, Fig. 1, rotated by gearing from the main shaft 20, carries a cam 126 acting on a lever connected by a link 131. Fig. 3, to a yoke 32 controlling the movement of a clutch member 26 adapted to couple a shaft rotated by gears 21, 23 from the main shaft 20 to a shaft 29 in alignment therewith. The shaft 29 carries a bevel gear 27 for rotating the core 13, on which is mounted a cam 35 having two diametrically-opposite notches adapted to be engaged by a roller on the end of a link 38. The link is connected to the yoke 32, and when the roller is forced by a spring into either of the notches, the clutch 26 is disconnected so as to stop the rotation of the core after a half revolution. Back-operating mechanism. The back is formed with two semi-cylindrical casting-surfaces 48, Figs 1, 13, and 17, and is rotatably mounted on a fixed column 90 carried by a slide 64. Passages 91 for cooling water are arranged concentric with the casting-surfaces, and the passage adjacent the casting-surface in use is connected with passages in the column 90. The back is preferably in two relatively-rotatable parts, the water passages in the column being connected with the passages in each half. The slide 64 is mounted on rollers 63 running on tracks 62 on a platform. 61 extending from the frame 10, guides 65 for the slide being also provided. The slide is connected by arms 53 to cranks 52 on a shaft 51, on which is also mounted an arm 56 adapted to be oscillated by a cam 151 on the shaft 125. The shaft 51 carries a double-ended clutch member 57 actuated by a hand-lever 60. When the lever is moved into the right-hand dotted line position in Fig. 29, the shaft 51 is clutched to the arm 56 and so is oscillated by the cam 151 to withdraw and return the back. This is effected auto. matically and occurs after each cast when a number of casts is to be made from a single matrix. If the back is to be drawn farther away to enable a matrix or the casting-surface to be changed, the lever 60 is changed to the left-hand dotted line position to couple the shaft 51 to a wormwheel 162 engaging a worm 161 on a constantlyrotating shaft 100. On the shaft 51 is a disc 163 having two teeth 164, 165, Fig. 1, the latter being twice as high as the former. After half a revolution of the shaft, the tooth 164 engages a projection 166 on the lever 60 and pushes it and the clutch 57 into neutral position, thus stopping the revolution of the shaft when the back has been fully retracted. To return the back, the lever 60 is again pushed to the left to couple the shafts 51, 100 together, and after a further half-revolution, the tooth 165 engages the projection 166 and forces the, lever 60 over to the right-hand dotted line position wherein the shaft 51 is again coupled to the arm 56 for automatic reciprocation of the back under the influence of the cam 151 after every cast. When the back is fully withdrawn, it can be rotated to change the casting-surface. The lower part of the back is rotated by bevelgearing from a shaft 97, Fig. 13, driven by worm gearing 99 from the constantly-rotating shaft 100, the worm being slidable on the shaft 100. The shaft 97 is connected to the shaft 100 by a clutch 101 actuated by a lever 109 and link 102 from a hand-lever 103. The lever 103 is normally held by a spring in a position in which a projection 106 thereon engages one of two diametrically-opposite notches in a disc 110 on the back, in which position the clutch 101 is disengaged, so that the rotation of the back is stopped after a half revolution. The top half of the back is provided with similar mechanism, actuated by a hand-lever 203 for simultaneous or separate rotation as desired. In a modification, the withdrawal of the back is effected manually. An operating-handle 50, Fig. 39, is secured to the shaft 51 connected by gears to a shaft 54 carrying the cranks 52. A cam 210, loose on the shaft 51, carries two spring-pressed pawls 216, Fig. 41, which lies in the path of rotation of two pins 218 in a collar 217 secured to the shaft. When the shaft is rotated to withdraw the back, the cam is rotated by the pins 218, and on withdrawal of the back to its full extent, the cam engages a lever 212 connected by a link 213 to a member attached to the lever 103 so that the clutch 101 is thrown in and the back rotated. Metal-supply arrangements. Molten metal is supplied to the mould through a spout 178, Figs. 1, 24, and 25, from a melting-pot 19, by means of a piston 172 acting in a cylinder 171. The piston is actuated by means of connections 173- 175 from a cam 170 on the shaft 125. The piston acts once for each revolution of the shaft 125 on each half-revolution of the core, and means is provided for preventing the discharge of metal when the back of the mould is withdrawn for changing the matrix. This consists of a frame 181 attached to the slide 64 and slidable on the shaft 100, the frame being provided with a cam 182 which, when the back is fully withdrawn, engages a roller on an arm 184. The arm 184 is fixed to a shaft 185 carrying a second arm 186 connected b va link 187 with a bell-crank 188. The bell-crank acts on a rod 191 carrying a valve 180 which is normallv held by a spring acting on the bell-crank in such a position as to close a port 179 in the cylinder 171. Casting-arrangements. The mould is of such a length that two single-width plates can be cast therein end to end. For this purpose the adjacent edges of two matrices M, M<1>, Fig. 17, are held by the flanges of a T-shaped semicircular strip 66 located in a recess 67 in the back. For casting a double-width plate, the strip 66 is replaced by a filling-piece in the recess 67 to prevent buckling of the matrix at this point. One singlewidth plate can also be cast in the upper part of the mould by inserting a T-shaped foot-bar in the recess 67, the bar holding the lower edge of the matrix and extending completely across the mould-cavity. Trimming-mechanism. When the core 13 commences to rotate, a cam 149, Figs. 1 and 22, on the shaft 125 acts on a lever 140 connected to a pivoted bracket. Two brackets 46, normally connected together for simultaneous action, are provided, and carry shafts 45, Fig. 3, on which are mounted saws, the saws being thus moved into operating position for trimming the cast when the core rotates. For trimming two singlewidth plates, four saws are provided, two on each shaft 45. The saw 49 trims the upper edge of the top plates and separates the riser, the saws 49a, 49b trim the adjacent edges of the plates and separate the waste piece, and the saw 49<c> trims the lower edge of the bottom plate. For trimming a double-width plate, the saws 49<a>, 49<b> are removed, and for trimming a singe-width plate, the saws 49<b>, 49<c> are removed. The shafts 45 are driven by belts from two shafts 41 which are also connected for simultaneous operation, and are rotated continuously by gearing from the shafts 20. In the modification shown in Fig. 39, one of the saw-shaft brackets is connected by a link 260 to a lever 259 rocked by a groove 257 in a cam 256 on the shaft 51. The cam groove 257 is in two parts, the first part effecting the movement of the saws when the handle 50 is swung over sufficiently free to withdraw the back for enabling the cast plate to be removed in the ordinary way. The second part of the groove 257 is concentric, so that movement of the handle 50 to withdraw the back to its full extent does not affect the position of the saws. The plates are pushed off the core on to platform 70, 71, Fig. 3, the upper one of which is removable to permit the ejection of a doublewidth plate.