GB552335A - Improvements in or relating to presses such as printing presses - Google Patents

Abstract

552,335. Printing-machines. STEVENS, A. H. (Miller Printing Machinery Co.). Aug. 5 1941 No. 9938. [Class 100 (ii)] A two-revolution flat bed printing-machine in which the bed 17 reciprocates on four trackways 18 arranged between side frames, 10, 11 and supported by a cross beam 19 is driven by a motor 27 driving a sprocket 29 on a shaft 30 formed with a gear 32 arranged outside the frame 11 and adapted to drive a main shaft 44 on which is splined a gear 53 engaging a a central rack 56 on the bed for driving the bed at uniform speed during the printing operation. The shaft 44 drives the impression cylinder by means of a pair of gears 43, 45 and also drives a pair of crankshafts 34, 47 adapted to reverse the bed by cooperation with a central hanger 40 carried by the bed. The hanger 40 is formed with surfaces 41, 42 each arranged at an angle of 45 degrees to the machine base, and rollers 38, 52 of the crank pins 38, 51 first engage the lower edges of the surfaces 41, 42 to stop the motion of the bed, and in the case of the roller 38 further clockwise movement causes pressure of the roller on the upper side of the surface 41 and starts movement of the bed towards the left. The gear 53 is moved out of engagement with rack 56 by means of a cam 69, Fig. 3, which actuates a shifteryoke 70 provided with a block engaging a groove in a collar 61 on a gear 60 which is made to engage a rack 62 during the non-printing motion of the bed, the yoke 70 being linked to a similar yoke 74 which moves the gear 53 out of engagement with the rack 56. The shaft 65 of cam 68 is driven from the shaft 44 and is geared to a control shaft for a suction feed device, and is also fitted with a cam which oscillates a segmental gear 83 geared to an eccentric 87 connected by a push rod 88 to the eccentric bearings of the impression cylinder 14. The reversing rack 62 is arranged between the central rack 56 and a driving- rack 25a for the inking-apparatus, and this arrangement is adapted to prevent skewing of the bed upon reversal. The construction is adapted to shorten the span of the bed between the inner tracks 18 and to limit the deflection of the bed during printing. Also the location of the reversing gears beyond the side frame enables larger gears to be used which may be made of cast iron. The main driving-gears may be of single or double helical type, and may be enclosed in an oil casing. Specification 552,361 is referred to.