Patent GB-189806321-A (GB)
Title: Improvements in Bed and Cylinder Printing Machines.
Inventor: NEWTON HENRY EDWARD
Filed: 1898-03-15
Granted: 1899-03-15
Abstract: 6321. Newton, H. E., [Hoe, R.]. March 15. Cylinder machines with plane printing-surfaces.-The first part of the invention relates to machines in which the cylinder (or cylinders) is constantly rotated m one direction, and is geared to a rack on the bed during the printing movement, and consists of arrangements whereby the cylinder is driven by a rack on the bed at the time of the impression, and during the remainder of its movements is driven by independent constant speed gearing, at about the speed at which it is moved by the rack when it is just engaged with or about to be disengaged from the rack. Fig. 1 shows a side view of a machine in which K is the impression cylinder and B the reciprocating bed. The bed is reciprocated by a railroad gear C gearing with a rack F on the bed and a fixed rack G on the framing. The wheel C is moved by a rod E connected to a crank-pin H on a crank-wheel D, driven by a pinion on the shaft I. The cylinder is raised and lowered so as to be clear of the forme except during the time of the impression, by means of toggles 14, 15, the upper members 15 of which are pivoted on the framing M, and the lower members 14 are pivoted to slides 13. To the slides 13 are connected the lower ends of rods 12 the upper ends of which are fixed to the sliding bearings L of the cylinder shaft K<1>. The toggle 14, 15 is made and broken by a rod 23 having a double hook at its end adapted to engage either of the pins 27 or 28 on a lever 29 pivoted to the frame at its lower end, and operated by a cam 31 on the crank shaft R. The rod 23 is normally engaged with the pin 27 on the lever 29, and the movement of the toggle is then sufficient to depress the cylinder into printing contact with the bed ; but when it is desired to 'throw off' the impression, and at the same time depress the cylinder sufficiently for it to be geared with the rack on the bed, the end of the rod 23 is moved down to engage the pin 28 on the lever 29. The end of the rod 23 is moved by a link connected to a lever 34 operated in one direction by a spring 35 and in the other by a push-rod 37 under control of the operator. The end of the rod 23 is prevented from moving from one pin 27 or 28 to the other except at proper times by a cam on the shaft R engaging an extension on the rod 23. On the bed B is a rack 11 of a length sufficient to drive the cylinder through the impression movement, and during the impression the rack gears with the wheel 10 on the cylinder. During the time that the cylinder is disengaged from the rack 11 it is driven by a train of gearing from the shaft R. The gear D<1> on the crank-wheel D drives a pinion D<2> on a countershaft N, on which is also a pinion 41 gearing with a wheel 42 also gearing with a wheel 43 carried by a slide 18 which moves with the rods 12. The wheel 43 is geared with a wheel 45 loosely mounted on the cylinder shaft. On the gear 45 are pivoted at 51, Fig. 8, a number of spring arms or pawls 49 having at their free ends pairs of rollers 52 the inner ones of which engage notches or recesses 48 in a disc 47 fixed on the cylinder shaft K<1> and so drive the cylinder when it is clear of the rack 11. The spring arms 49 are locked in engagement with the disc 47 by means of a cam 55, the parts 57 of which engage the outer rollers 52 when the inner rollers 52 are in the notches 48. When the rack on the bed commences to drive the cylinder its speed increases, the disc 47 consequently moves faster than the arms 49, and the rollers 52 are lifted out of the recesses 48, parts 56 on the cam-ring 55 permitting this. When the end of the printing movement is reached, the notches 48 come again into position to be engaged by the spring arms. The locking cam-ring 55 is driven at a somewhat slower speed than the wheel 45 by a pinion rotating with the wheel 43. In a modification of this clutch or connecting arrangement, the arms 49 are provided with noses or projections for engaging notches in the disc 47, and they are locked and released by arms on their pivots having rollers running on the periphery of a cam disc driven similarly to the cam-ring 55. Other forms of clutch or means for connecting the cylinder shaft with the train of gearing may be employed. In one arrangement, the part of the clutch rotated by the train of gearing is movable longitudinally to the cylinder shaft, and is operated by a cam so that pins thereon engage with or are disengaged from corresponding holes or recesses on a part fixed to the cylinder shaft. In another modification, the last wheel of the train of gearing is a pinion which gears with an internal toothed wheel on the cylinder shaft when the cylinder is in raised position, but when the cylinder is depressed the wheel moves out of gear with the pinion. The cylinder gear 10 is brought properly into gear with the rack 11 by means of a roller P on the cylinder engaging a cam or horn 0 on the bed. The second part of the invention relates to air-cushioning devices for assisting the reversal of the movement of the bed. Fig. 27 shows a machine having a cylinder K and reciprocating bed B. On the bed are fixed the pistons 201 which enter the air cylinders 202, 204 at the ends of the strokes. The ends of the air cylinders are provided with air passages 211 adapted to be closed by pivoted flap valves 214 when the pistons enter the cylinders in the ordinary working of the machine. The valves 214 close against inclined seats, so that, when the bed and cylinder are being moved slowly by hand when making ready &c., the pistons entering and moving the cylinders slowly do not close the valves. The air cylinders are connected by pipes 220 to safety or relief valves kept closed by levers having sliding adjustable weights 226 for varying the pressure at which the safety-valves open. The weights 226 are connected by rods 241 to arms 242 of a shaft 244 operated by an arm 208 connected to the belt-shifting lever 240. When the belt is shifted on to the loose pulley the weight is moved nearer the -pivot of the valve lever, and less pressure is then required to open the valves.