Patent GB-263375-A (GB)
Title: Improvements in and relating to the manufacture of printing plates
IPC: B41D3/00
Filed: 1926-04-21
Abstract: 263,375. Marks, E. C. R., (Wood Newspaper Machinery Corporation). April 21, 1926. Stereotype, casting and finishing. The finishing-operation is performed by a tool which is caused to traverse the back of the cast plate while the latter is held in direct contact with the back of the mould from which the matrix has been removed. The mould consists of a back, and a core rotatable therein, and means for starting the rotation and for automatically stopping it after two revolutions are provided. The riser is severed before the rotation is started, the matrix is stripped from the plate during the first half-revolution of the core, the second half-revolution repositions the plate in the back wherein it is shaved during the third half-revolution and from which it is ejected during the fourth half-revolution. The mould consists of a watercooled back 21 and core 22, Figs. 6 and 9, sidebars 37, and a matrix cLamp 25 and clip 33. The bars 37 are bevelled to cast corresponding bevels on the plate and are adapted to hold the curved edges of the matrix. One straight edge of the matrix is received in a notch in the pouring- funnel 35, and the other straight edge in a slot in the clamp 25. The clamp 25 is pivoted on a shaft 26, Figs. 2, 8 and 9, surrounded by a spring 28 tending to hold the clamp in open position. The clip 33 is pivoted on a shaft 29 and is acted on by a spring 30 tending to close it. A handle 24 on the shaft 26 facilitates the closing of the clamp 25, and when closed it is engaged by hooks 75 on arms 74 pivoted at each side of the back 21 and held in locking-position by springs 77. The core is provided with square ribs 82, Fig. 6, and pins 80, Fig. 9, for facilitating the withdrawal of the cast plate when the core is rotated, and with a number of unequally spaced circumferential depressions 81 of a depth equal to the thickness of a matrix so as to cast a series of corresponding projections on the back of the plate. The core is mounted on a shaft 20, Figs. 2 and 3, adapted to be coupled to a constantlyrotating shaft 10. The clutch operating-handle 12 is slidably keyed to a shaft 18 and is provided with a projection 8 adapted to engage, when the handle is moved to couple the shafts 10, 20 together, in a screw-thread 7 on the shaft 20. Secured to the shaft 18 are arms. one of which is connected to a spring-pressed rod 19 arranged to hold the handle 12 in position either to couple or uncouple the shafts 10, 20, and another carries a roller 15 engaging a cam 16, provided with a notch 17, on the shaft 20. Rotation of the shaft moves the projection 8 along the screw-thread 7, until, near the end of the second revolution of the shaft, a projection 6 thereon forces the projection 8 out of the thread. This turns the shaft 18 and so disconnects the clutch. The handle 12 and projection 8 are returned to their original positions by a spring 5. When the cast plate has cooled, the pouring-funnel 35, Fig. 9, is raised by releasing a spring-pressed hook 67 from engagement with a treadle 66 connected by a spring-pressed rod 64 to tho funnel. The riser is severed by means of a constantly-rotating saw 60, Fig. 4, mounted in a carriage 51 slidable on a track 52 on the back 21 of the mould. The carriage is connected to a chain 49 engaged by a gear-wheel 46 on a shaft 48 provided with an operating-handle 47. Movement of the handle 47 through 180‹ causes the saw to traverse the plate in one direction or the other to sever the riser. The handle 12 is then moved to set the core in rotation. A projection on an arm 69, Figs. 3 and 8, on the operating-handle 12 engages an arm 71 on a shaft 72 to rotate the shaft and cause cams 73 thereon to engage the arms 74 and unlock the matrix-clamps 25, which open under the influence of the spring 28. As soon as the core starts to rotate, a cam 44, Fig. 6, on the shaft 20 operates a lever 45 connected by a link 40 to a crank-plate 41 connected by two links 42 to levers 43 carrying the side-bars 37. The bars 37 are thus withdrawn to release the matrix and the cast plate. Rotation of the core causes the movement of the plate and matrix out of the back, and the matrix can then be removed from the plate. Continued rotation of the core repositions the plate in the mould. The clamp 25 is again closed, the arm 69 having moved out of position for engaging the arm 71. The plate is thus prevented from movement out of the back, and, on the continued rotation of the core, the pins 80 cut their way out of the plate. The projections on the plate, formed by the depressions 81 on the core, are engaged by the circular Fart of the core and the plate is thus pushed constantly against the back. A blade 62, Fig. 9, secured to the core then shaves the inside of the plate. After the shaving is complete, projections 78, Fig. 8, on the core engage projections 79 on the levers 74 to release the clamps 25, which open to allow the plate to be ejected during the final half-revolution of the core by the engagement of the projections 81 with the rear edges of the plate.