Patent GB-284983-A (GB)
Title: Improvements in stereotype-matrix forming machines
IPC: B41D1/00
Filed: 1927-03-28
Abstract: 284,983. Goss Printing Press Co., (Assignees of Smith, E. J.). Feb. 7, 1927, [Convention date]. Embossing-machines.-In a press for forming stereotype matrices, of the kind having power means and hydraulic means for imparting a quick initial movement and a powerful final movement to a platen respectively, the hydraulic means comprises pumping-mechanism which is automatically rendered effective at a predetermined point during the initial movement of the platen; automatic means may be provided for maintaining the final pressure at a predetermined maximum. The apparatus shown in Figs. 1 and 4 comprises a stationary platen 22, and a vertically movable platen 20 carried by a piston 19 mounted in a cylinder 16. Steam for heating the platen 20 is introduced through a pipe 25. The platen 20 is moved initially by means of eccentrics 54 operated by a shaft 26 and provided with slotted links 55 engaging blocks 56 which are journaled on pins 57 on the platen, springs 58 being arranged between the links and blocks. The shaft 26 is driven through worm-gearing 28 by a shaft 30 which is connected by a chain-gearing 35 to a motor 36. The switch arm 39 of the motor switch 38- engages a sliding rod 40 which is connected by a link 43 to a hand-lever 42, a spring 45 normally holding the switch arm in open position. On depressing the hand-lever, the switch arm is closed, the platen 20 is raised by means of the eccentrics on the shaft 26, and a rocking arm 50 on the rod 40 engages the side of a stationary abutment 51 and retains the switch arms in the closed position. When the shaft 26 has made a half-revolution, a cam 47 thereon engages a finger 48 on the arm 50 and releases the arm from the abutment 51, whereupon the rod and hand-lever return to normal position, the switch arm is opened, and the motor and sha.ft 26 are arrested. The rod is flexibly connected to a brake 52 for braking the shaft 26 when the motor is arrested. The cylinder 16 is connected by a branch 62 and a pipe 60 to a pump 61 and an oil tank 59, and when the platen 20 is near the top of the stroke, the pump automatically applies an increased final pressure to the platen. The pump is operated by a motor 63 connected to a switch 66 having an arm 67 co-operating with lugs 68 on one of the links 55. The pipe 60 is connected to a return pipe 75 provided with a normally open valve 76 engaging a vertically movable rod 78 which is held in raised position by a spring 81<a> and is depressed periodically by a cam 80 on the shaft 26. The end of the rod slides in the valve stem 77 and has a pin engaging a slot 71<b> therein, a spring 79 arranged between collars on the rod and stem yielding when the rod is depressed. When the platen has been raised a short distance by the links 55, the pump is automatically started, and when the shaft 26 has made a half-revolution, the cam 80 closes the valve 76 and the pump applies an increased final pressure to the platen. When the pressure has been maintained for a time the hand-lever 42 is depressed, and the shaft 26 makes a half-revolution causing the links 55 to depress the platen. At the beginning of the movement, the valve 76 is opened and oil is permitted to return through the pipe 75 to the tank. The motor 63 and pump 61 are arrested after a short movement of the platen. For stopping and starting the pump when the pressure in the cylinder rises above or falls below a predetermined adjustable maximum, the motor 63 is provided with a second switch 65 connected to a piston 73 mounted in a cylinder 70 which is connected by a pipe 71 to the pipe 60. The switch is normally closed, but when the pressure rises above the maximum, the piston is depressed in opposition to an adjustable spring 74, the switch is opened, and the motor and pump are arrested until the pressure falls below the maximum. In a modified form of apparatus, a single motor drives the shaft 26 and pump 61, the shaft 30 being geared by a chain to the pump, and the worm 28 being connected to the shaft by a clutch controlled by the rod 40. The switch 38 is arranged in parallel with contacts co-operating with a contact plate on the shaft 26 and so arranged that when the switch arm 38 is opened by the rod 40, the circuit of the motor is maintained. When the hand-lever 42 is depressed the switch arm 38 starts the motor, the clutch is thrown in, the shaft 26 makes a half-revolution, and the platen is raised by the links 55. Thereupon the clutch is thrown out and the shaft 26 is arrested, the motor however continuing to operate the pump. When the hand-lever is again depressed, the shaft 26 makes another half-revolution, and the platen is depressed, the contactplate moving off the contacts. The pressure is regulated by an adjustable relief valve arranged in a branch pipe leading from the pipe 60 to the top of the tank 59.