GB441487A - Improvements in or relating to doctor blade mechanism for use with intaglio printingmachines - Google Patents

Abstract

441,487. Printing - machines. QUICK, C. G., BENNISON, W. E., ALEXANDER, D. A. H., and'MARTIN, E. G. L., 109, Borough Road, London. July 17, 1934, No. 20935. [Class 100 (ii)] Inking-apparatus.-In a rotary intaglio printing- machine the doctor blade holder is connected to a fluid-pressure-operated device whereby the blade may be lifted out of contact with the printing cylinder. The holder is also manually operable to move the blade into a further inoperative position, this movement being permitted by a lost motion device in the connections between the fluid-pressure device and the blade holder. As shown, the cylinder 1, Fig. 1, which is inked by a roller 2<1> rotating in a fountain 2, is provided with two doctor blades 3, 4 for alternative use according to the direction in which the cylinder is rotated. Each blade is carried by a holder 5 secured to blocks 6, Figs. 1 and 2, carried by a shaft 8 which is turned in a direction to move the blade to an inoperative position by means of fluidpressure cylinders 13, the piston rods of which are formed as racks engaging gear sectors 9 on the shaft. The sectors are loose on the shaft and impart movement thereto by the engagement of internal lugs on the sectors with lugs on the shaft. This arrangement permits the blades to be moved into a further inoperative position for cleaning &c. purposes by means of a handle 18 fixed to the shaft, a pawl 19 engaging a notch 20 in a fixed part 21 to hold the blade in this position. The blade is moved into operative position upon releasing the handle 18, by an adjustable spring 14 on the shaft 8, this movement being controlled by adjustable needle valves provided in the exhaust from the cylinders 13. The shaft 8 is supported by a base plate 27 movable to and from the cylinder 1 on an underframe 28 by threaded rods 29 geared to a cross-shaft 32 actuated by gearing from a hand wheel 37. The underframe 28 is mounted to reciprocate on the main frame 42 in a direction parallel to the axis of the cylinder. The underframe of the doctor blade 4 is connected by a rod 43 to a crank-pin 44 on a disc 45 fixed to a shaft 45<1> rotatable from a suitable part of the machine by a worm 45<3> and worm wheel 45<2>. The underframe of the doctor blade 3 is reciprocated from the shaft 451 by means of a second crank disc 54 thereon, connecting rod 52 arms 51<1>, 50 on a vertical shaft 51 and rod connecting the arm 50 and underframe 28. The crank-pins 44, 53 are adjustable in diametrical slots in the discs and by placing either pin at the centre of its disc the reciprocating movement of the corresponding doctor blade can be arrested. In a multi-unit machine, the supply of pressure fluid to all the cylinders may be controlled by a single valve for simultaneous operation of all the blades, or the supply may be controlled by a valve mechanism as described in Specification 441,490, to permit actuation of the blades independently or in selected groups. Hinged covers 47 are provided for closing the spaces between the edges of the duct 2 and the roller 1, these covers being held in a suitable position according to the diameter of the printing cylinder by keys placed in holes 48.