GB190525253A - Improvements in Pressure Controlling Devices for the Air-springs of Printing Presses. - Google Patents

Abstract

25,253. Lake, H. H., [Cottrell & Sons Co., C. B.]. Dec. 5. Cylinder machines with plane printing-surfaces.- Relates to pneumatic cushioning-mechanism for the reciprocating beds of cylinder printing-machines, provided with means for controlling the air pressure. The bed 12 is reciprocated in the usual manner by means of a pinion 16 on a shaft 15 and a rack 17, Fig. 2, the rack being provided at each end with a roller 18 and a semicircular shoe 19, with which engage rollers 20 on the pinion 16, to direct the pinion from one side of the rack to the other. On the bed 12 are two cylinders 22, which are provided with air-inlet valves 23 and are adapted to receive, at each end of the travel of the bed, pistons 24 secured to the frame 11. The air space in the cylinder 22 communicates by way of the hollow piston-rod 25 and pipe 26 with a cylinder 27, fitted with a piston 28, the motion of which is controlled by a cam 29 on a shaft 31, driven by bevel-gearing 35, 36 to make two revolutions to every complete reciprocation of the bed. The rod 28* is forked to embrace the shaft 31, and carries a roller 37, which rests on the cam 29, Fig. 4. When the piston 24 enters the cylinder 22, the piston 28 is at the top of the cylinder 27, as shown in Fig. 2. As the bed passes any predetermined point, preferably that at which its motion commences to be retarded, the projection 38 on the cam 29 passes the roller 37, allowing the piston to fall to reduce, keep constant, or otherwise adjust, the pressure in the cylinder 22. By varying the dimensions of the cylinder 27 and the form of the cam 29, the air pressure in the cushioning-cylinders 22 may be regulated to any extent, preferably retaining a sufficient final pressure to assist in restarting the bed. The bed may be reciprocated in any other manner.