GB814176A - An impression cylinder lifting mechanism for oscillating cylinder printing machines - Google Patents

Abstract

814,176. Printing-machines. DRUCKAUTOMATENWERK VEB. Oct. 3, 1955, No. 28094/55. Class 100(2) An impression cylinder lifting mechanism for oscillating- cylinder printing machines in which the impression cylinder is oscillated by a pinion secured to the cylinder shaft and driven by a rack on a reciprocating printing or type bed aranged beneath the cylinder, comprises a first lever system which controls the up and down movement of the cylinder during the return stroke of the bed when the lifting mechanism is set to printing position and a second lever system which controls the up and down movement of the cylinder during both forward and return strokes of the bed when the machine has been set to the non-printing position, the pinion being in full engagement with the rack at the points of reversal of the direction of the reciprocating bed at the end of each stroke whether printing or not printing. The impression cylinder 25, Fig. 4, is supported by a shaft 33 having blocks 23 slidable in bearings 34. The blocks 23, which are pressed upwardly by springs 24, are raised and lowered by toggle levers 19, 20. The lever 19, pivoted to the machine frame at 21, is actuated by levers 17, 18, and 14. The lever 14 is connected to a lever 10 through a shaft 13, such that rotation of a cam 2 mounted on a shaft 31 causes rocking of lever 14 through a lever 8 carrying a cam follower 7 and through a rod 9 connecting the levers 8 and 10. The lever 10 is urged by a spring 16, such that the cam follower 7 engages the cam 2. Thus, the cylinder is raised and lowered by the cam 2 which has two depressions in its circumference and rotates once for each revolution of the cylinder When it is not desired to print on a sheet, the cylinder 25 is raised and lowered during each forward and return stroke of the bed by the cam 2. During normal printing, the cylinder 25 is raised during the non-printing return stroke of the bed by a cam 1 on the shaft 31 having a single depression in its circumference The cam 1 engages a cam follower 3 carried by a lever 4 pivoted to a connecting rod 5 which rocks a lever 6 mounted on the shaft 13 and urged by a spring 15, such that the cam follower 3 engages the cam 1. In this case, the levers 6 and 10 are coupled together by a pin 28, Fig. 5, which engages bushes 32 and 30 serving as pivots for the levers 10 and connecting rod 9 and the lever 6 and connecting rod 5 respectively. The pin 28, Fig. 5, is axially pressed by a spring 29 towards the bush 30, but may be withdrawn by a cam surface 39 on a lever 26 brought into engagement with a plate 27 secured to the pin 28. The timing of the cams 1 and 2, Fig. 4, is such that the cylinder is always in fully lowered position at the end of each stroke of the bed, thereby ensuring that the cylinder driving pinion not shown, is in full engagement with a rack, not shown, on the bed, so as to prevent impacts during bed reversal.