Patent GB-337728-A (GB)
Title: Improvements in and relating to the manufacture of stereotype printing plates
IPC: B41D3/00
Filed: 1929-07-01
Abstract: 337,728. Triggs, W. W., (Wood Newspaper Machinery Corporation). July 1, 1929. Strreotype, casting and finishing. - In a stereotype casting - machine having power - operated devices for moving the back to and from the core, the operation is controlled bv means actuated at each end of the movement of the back..The machine comprises a rotatable core 1, a reciprocable back 2, and a pump 13. In the form shown the machine is set into operation by actuation of a starting- switch 44, Fig. 8, which allows current to flow from the main 101 through the switch 44, coil 45, closed stopswitch 81, and contacts 10 to the main 100. The excitation of the coil 45 closes a switch 46, one of the effects of which is to connect the coil 45 directly to the main 101 to maintain the switch closed after the switch 44 has opened automatically. The switch 46 connects a motor 8 to the mains, the motor being connected by worm-gearing 7, 6, Figs. 1 and 3, to a shaft 5 controlling the movements of the bach 2. The back carries a switch-bar 12, Fig. 8, having wedgeshaped ends and a central project:on 47. When the back moves towards the core the projection 47 engages a lever 48 and closes contacts 49 so that current flows from the main 101 through the contacts 49, coil 50, and contacts 59 to the main 100, and causes the closing of the contacts 51 and opening of the contacts 52. Current can now flow from the main through the contacts 51 to the coil 50, so keeping the contacts 51 closed and contacts 52 open. The back continues to move until the end of the bar 12 opens the contacts 10 and so cuts out the coil 45 causing the opening of the switch 46 and stopping of the motor 8. When the contacts 10 are opened, contacts 54 are closed to complete, a circuit from the main 101, contacts 51, 54, coil 55, and contacts 59 to the main 100, thus closing the switch 56 and starting the motor 20 to rotate. The motor 20 is connected to the piston-rod 15 of the pump 13, and causes the actuation of the pump to deliver a charge of metal to the mould, the correct amount being regulated by a stop 57 connected to the rod 15 and adapted to open the contacts 59, de-energize the coils 50, 55, open the contacts 51 and switch 56, and close the contacts 52. Current then flows from the main 101 through a coil 61, and contacts 52, 69 to the main 100, thus causing the closing of a switch 62 to connect the motor 20 to the mains in reverse direction and to return the piston to normal position. A stop 22 on the piston-rod is adjusted so as to close momentarily contacts 65 when the metal in the mould has had sufficient time to solidify, and a further stop 67 opens contacts 69 when the piston has returned to normal position thus de-energizing the coil 61 and stopping the motor 20. The closing of the contacts 65 results in the excitation of the coil 66, the closing of the switch 70, and the connection of the motor 8 for reverse rotation so as to withdraw the back. The worm-wheel 6, Figs. 1 and 3, carries a cam acting on a lever 37 connected by a link 37a to a frame pivoted on a continuouslyrotating shaft 30 and carrying a pair of trimming- saws 39 for removing the head and trimming the horizontal edges of the plate as it is carried round by the core 1. The saws are brought into operative position by the movement of the wormwheel to withdraw the back. As the back moves away from the core, the projection 47, Fig. 8, engages the lever 48 and closes contacts 71 and connects the solenoid 36 across the mains. At the conclusion of the movement of the back, the bar 12 opens the contacts 11, de-energizes the coil 66, and opens the switch 70 of the motor 8. The plunger 72 of the solenoid 36 is connected to a lever 35 having a roll adapted to engage either of a pair of diametrically-opposite notches in a plate 76 secured to the top of the core. The lever is also connected to a clutch-member 34 adapted to clutch a shaft 33, Figs. 1 and 3, to a worm-wheel 28 driven continuously from the shaft 30, which, in turn, is driven by the motor 32. The shaft 33 and core are provided with bevelwheels 27, 26. The movement of the lever 35 closes contacts 75, Fig. 8, to permit the passage of current to a coil 77 and cause the closing of pairs of contacts 78, 79 whereby the coil is maintained in active condition. At the completion of a half revolution of the core, the roll on the lever 35 enters the other notch on the plate 76, thus disconnecting the core from the motor 32, and closing contacts 80 and permitting the passage of current to the coil 45 so that the sequence of operations is repeated. Actuation of the stop-switch 8 only opens the circuit through the coil 45 so that the sequence of operations for the completion of a plate would be concluded. In a modification, the motor 32 is intermittently operated, and is thrown into circuit by the closing of a switch as the result of the excitement of a coil actuated by the lever 48 during the opening of the back. The coil is de-energized and the motor switch opened by opening contacts when the lever 35 enters one of the notches on the core plate 76. In a further modification. the piston of the pump is lifted by a solenoid, the circuit of which is broken by a stop on the piston rod at the limit of its movement to allow the piston to return by gravity.