PRINTING MACHINE HAVING A DEVICE FOR TRIPPING THE CYLINDERS
1329777 Rotary printing presses ADAMOVSKE STROJIRNY NARODNI PODNIK 1 Nov 1971 [9 Dec 1970] 50646/71 Heading B6C According to the invention there is provided an offset printing machine of the kind wherein paper sheets are printed by means of an impression cylinder, a forme cylinder and an offset cylinder which is brought into and out of printing contact with the other cylinders by rotation of an eccentric shaft on which the offset cylinder is mounted. The machine incorporates a tripping device operable automatically to bring the offset cylinder into and out of engagement with the other cylinders as paper sheets are fed through the machine, which tripping device comprises a cam 1 fixed to the shaft 2 of the impression cylinder 3, a lifting arm 9 having at one end a follower 4 which bears on the cam and at the other end a pin 10, a first link 12 rotatably mounted on the eccentric shaft 15 and having a tooth 11 engageable with the pin 10, a stop element 16 rigidly attached to the eccentric shaft 15, a pin 18 and slot 19 engagement between the first link 12 and a first arm of the stop element 16, a second arm of the stop element being engageable with a sheet thickness adjuster 20 mounted in a bus 9 on a side wall 8 of the machine and adjustable to control the amount of rotation of the eccentric shaft it accommodates paper of different thicknesses.