GB238394A - Improvements in or relating to printing presses - Google Patents

Abstract

238,394. Grosskopf, R. Sept. 19, 1924. Rotary machines; tripping-arrangements.-In a. printing-machine having an intermittentlyrotated impression cylinder, a pointer moving over a scale is provided to indicate when the cylinder is stationary, so that the cylinder may be thrown into and out of gear during this period if a sheet is fed to it in an out-of-register position. In a stop-cylinder machine, the printing- cylinder b is driven from the shaft a through gears a<1>, c, the latter of which engages a gear d having a cut-away portion d<1> so as to drive the impression cylinder e intermittently. Arms c<2>, d<2> on the two shafts cause the re-engagement of the gears c, d, and a roller g on a spring-pressed arm engages a notch in a drum f to hold the impression cylinder in the stationary position. To disengage the impression cylinder if a sheet is fed out of register, a handoperated lever h is provided to move the cylinder e axially and thus disengage the gears c, d. To avoid shock, the engagement and disengagement of the cylinder must be effected while it is stationary, and this period is indicated by a pointer l moving over a marked sector m and driven from the shaft b<1> of the printing-cylinder by pinions i, k. The pointer may be operated from the. shaft a or oscillated by a cam disc attached to the pinion k.