Patent GB-651331-A (GB)
Title: Improvements in or relating to stereotype plate casting machines
IPC: B41D3/00
Filed: 1947-07-09
Abstract: 651,331. Casting stereotype plates. GOSS PRINTING PRESS CO., Ltd. July 9, 1947, No. 18164. Convention date, Nov. 15, 1946. [Class 100 (ii)] A machine for casting stereotype plates with recesses in the backs thereof comprises a core, a collar element movable longitudinally relatively to the core to move a cast plate relative to the latter, a bar element adapted to carry recess-forming portions and slidable in a groove in the core, and means to limit the longitudinal movement of the collar and bar elements with. respect to each other and to the core. Standards 10, Fig. 1, support a core 11, Fig. 2, for casting a cylindrical plate. A two-part drag 12, 13 is hinged at 14, being swingable about the hinges by a handle 15 and lockable in closed position by a handle 16. The core is tiltable by a handle 17 into and out of casting position. The matrix 21 is positioned by means of a parting strip 20 in the part 12, and a parting bar 22 on the core 11 forms the vertical walls of the casting chamber. A collar 25 surrounds the lower part of the core and has a reduced portion 26, Fig. 4, serving as a bottom for the chamber and also to eject the cast plate 23 by pushing it along the core when the latter is tilted, by means of pintles 27, 28 on the collar and arms 29, 30 mounted on the pintles 27, 28, the lower ends of the arms being pivoted on pintles 31, 32 on the standards 10. In the core 11, one on either side of the bar 22, is a pair of longitudinal grooves 35, downwardly tapered, to receive correspondingly tapered recess-forming bars 36, the grooves and bars having inclined edges 37, 38 to form a dovetailed joint. Grooves are also formed in the collar portion 26 to receive the outer part of the bars. The bars are thus movable longitudinally with respect to the core and to the collar 25. Each bar 36 on its outer face has a longitudinal cutaway portion providing a longitudinal recess-forming die portion 40, Figs. 2 and 3, extending into the casting chamber. The cutaway portion extends upwardly from substantially the level of the top of the portion 26 when the bar is in its uppermost position. The die portion is tapered upwardly. When the bar is moved upwardly in the groove 35 after casting, it becomes loose in the groove and can be forced away from the edge of the plate recess nearer the bar 22 to facilitate removal of the plate. The movement of the bar with respect to the core is limited by a screw 46 threaded through the bar, a part 47 of the screw extending into a deeper groove 48 in the core. The head 49 of the screw slides in a slot 50 in the part 26 to limit relative movement of the bar and collar. When the core is tilted, the collar 25 forces the plate, and therefore the bars 36, upwards until the screw parts 47 reach the top of the grooves 48, when the bars are arrested, while 'the collar continues to eject the plate until the lower edges of the slots 50 abut the screw heads 49, thereby easing the die portions 40 from engagement with the plate recesses. Adjacent each bar 36 is positioned an insert 52 in grooves in the core and in the internal surface of the part 26, so as to fit tightly against the core, collar and bar when the bar is in its lowermost position, to prevent molten metal seeping between the bar and the collar and core. The apparatus can also be adapted for use in casting semicylindrical plates.