Patent GB-636191-A (GB)
Title: Improvements in stereotype plate finishing machines
IPC: B41D5/00
Filed: 1946-12-30
Abstract: 636,191. Stereotype. WOOD NEWSPAPER MACHINERY CORPORATION. Dec. 30, 1946, No. 38047. Convention date, Sept. 10. [Class 100 (ii)] A machine for milling precisely located pockets on the inner concave surface of semicylindrical stereotype plates comprises a platecarrying cylinder having in its wall two longitudinal slots, means for clamping a plate to the outer surface of the cylinder over the slots, milling cutters within the cylinder, and means for moving the cutters laterally of the plate in unison and outwardly of the cylinder through one of the slots. The stereotype plate A, Figs. 1 and 4, is clamped to a cylinder 1 journalled in bearings 3, 4 on the main frame 5 of the machine, by means of a clamp 2, being positioned laterally by stops 46, 47 and longitudinally by stops 48, 49. The cylinder has longitudinal slots X, Y through which tension lock-up pockets are cut in the plate by rotary cutters 6 carried on a cutter bar 7 journalled in bearings 60, 61 in the frame. The cutters are rotated through bevel gearing by a shaft 12 driven by an electric motor 8 carried on an adjustable base 9 through pulley and V-belt drive. The shaft 12 drives at a slow speed a shaft 24 through a worm-gear train 25, 28. The shaft 24 drives a shaft 18 through a crank arm 21, rod 22 connected thereto through a spring member 23, and crank member 20. The member 20 comprises a crank arm 73 and a gear segment 65 whose movement is limited by two stops on the frame, whereby the motion of the shaft 18 is oscillatory through about a rightangle. The shaft 18 moves the cutters into cutting position alternately at the slots X, Y by means of a crank lever M and sliding block 16 oscillating the bar 7. The gear segment 65 drives a shaft 41 through a pinion 42. The shaft 41 is journalled in bearings in a bracket 33, and in a bracket 37 fixed to the cylinder, and carries rotary segmental shavers 40 to finish the locating surfaces C and D of the plate. The gearing is such that during one revolution of the shaft 24, the bar 7 makes one double oscillation, and the shaft 41 one complete revolution in either direction. The cylinder 1 is reciprocated longitudinally by the bracket 33 connected thereto by a screwed rod 34, and reciprocated by a lever 30 and cam 29 on the shaft 24. Four registry indicators 43 are provided, carried on levers 44 on shafts 45 and movable into and out of position by handles 69. The cylinder is rotated to effect lateral adjustment of the plate by means of hand wheels 39 fixed to a screwed rod 38 engaging by means of an internally threaded pin 70 contacting a U-shaped member 36 journalled around the bearing 4 and acting against the bracket 37 on the cylinder. Longitudinal adjustment is effected by a hand wheel 35 on the screwed rod 34. The bracket 33 is connected to the rod 30 by a double pivot to allow it to rotate with the cylinder during the lateral adjustments. The frame is formed with. a hopper bottom 71 to receive a removable box 72 for collection of shavings. In operation, the motor is started by a switch 52, and the machine stops after one revolution of the shaft 24 by means of a cam 53 actuating a cut-out switch. The cutters are brought to cutting speed, moved from a rest position near the slot Y into cutting position at the slot X, the cylinder is reciprocated longitudinally, the cutter is moved into operation at the slot Y, the cylinder moves back longitudinally, and the cutter returns to rest position. During this time the shavers 40 make one revolution in either direction. If registry means are not required, the cylinder can be hinged in the bearing 3 to allow no rotation, and fixed directly to the bracket 33, the members 34, 35 being omitted, and the mechanism 38, 39 is also omitted. In a modification, Fig. 10, the cylinder has four longitudinal slots 82, in each of which is a fixed block 76 carrying a screwed rod 77 with a squared portion 83 for turning by a spanner, and a milled part 79 for hand operation. The other end of the rod 77 is fixed by a ball 80 in a slidable block 75 having a jaw 84 to engage the plate A, whereby any slight misalignment of the printing impression can be corrected by turning the requisite rods 77 to produce a distortion of the plate A within the limits of its elasticity. Specification 636,189 is referred to.