GB945291A - Improvements in or relating to printing presses - Google Patents

Abstract

945,291. Printing-apparatus. MIEHLEGOSS-DEXTER Inc. July 16, 1962 [Sept. 22, 1961], No. 27169/62. Heading B6C. A printing press of the type having an intermittently rotating impression cylinder 12 and an oscillating delivery arm shaft 20 is provided with a tripping mechanism which is adapted to stop the press if the impression cylinder fails to rotate during an operation which would otherwise print a sheet and comprises a tripping lever 44 movable from a normal non-tripped position to a tripped position to stop operation of the press and an actuating link member 32 which is moved during a printing operation partly by the oscillation of the shaft 20 and partly by the rotation of the impression cylinder 12, said link being arranged to move the lever 44 into the tripped position when the movement of the link is produced by the oscillation of the shaft 20 alone owing to a failure of the impression cylinder 12 to rotate during an operation which would otherwise print a sheet. The cylinder 12 co-operates with the forme 13 of a vertically reciprocable bed 10 and rotates only on the downstroke of the bed; during the upstroke the cylinder is off impression and stationary. Delivery arms 18 mounted on the shaft 20 are provided with grippers 21 which co-operate with the cylinder 12 for gripping and removing a printed sheet from the grippers 22 of the cylinder. An eccentric 23 on the shaft 14 of the cylinder 12 is connected to a bell crank lever 25 by a rod 26 and the other leg of the bell crank lever is connected at 28 to a connecting rod 30 which is pivotally joined at 31 to the link 32. The other end of the link 32 is pivoted at 33 to a member 34 fixed to the shaft 20. A spring 37 is provided to absorb counterclockwise rotation of the bell crank lever if the rod 30 is held against movement. If a sheet is not presented to the cylinder 12 or if a sheet is improperly registered, sheet detecting means trip the cylinder 12 off impression and the cylinder remains stationary. The rod 30 also remains stationary and the end 40 of the link 32 is moved to the right under the action of the shaft 20 only and the end 40 contacts a projection 48 and rocks the trip lever 44 in a clockwise direction. The arcuate end 54 of the lever 44 is thus elevated and raises a yoke 55 which releases friction looking elements 66 and 67 and allows the control shaft 64 to move to a stop position under spring pressure. The press is accordingly stopped. The press may also be stopped or its speed varied by lowering a handle 60 and raising the yolk 55 by means of a rod 57. A manually operable pin 76 is provided to elevate a control bar 42 to a position above the projection 48, Fig. 6 (not shown), so as to render the tripping mechanism inoperative for makeready, inking up or for other preliminary operations. A trip resetting means in the form of a crescent-shaped member 80 is provided in case sheets are fed to the press for regular printing with the control bar 42 still in the elevated triprelease position.