GB310257A - Improvements in printing presses - Google Patents

Abstract

310,257. Miehle Printing Press & Manufacturing Co. June 15, 1928, [Convention date]. Gripper mechanism.-In a sheetfeeding apparatus for printing-machines of the kind in which sheets are fed from a fixed table by oscillating grippers which transfer the sheets to the impression cylinder while travelling at the same speed as the grippers thereof, the transfer grippers 92, Fig. 5, are carried by an arm 14, Fig. 1, which can be swung automatically or by hand into the inoperative position shown in Fig. 7 and held therein so as to trip the feeding apparatus. The automatic means for holding arm 14 in an inoperative position comprises a spring-controlled plunger 27 which is arranged to engage automatically in a recess in one of the sector gears which effect the normal oscillation of the shaft 17 of the arm 14. The sheets are normally registered against stops 102, Fig. 5, on spring-mounted pads 99 cooperating with the grippers 92, the pads being capable of rotation through 180‹ and held with the stops 102 out of action so that when line register is desired a portion only of the stops are in action. The grippers 92 are spring-closed and are normally opened for taking and delivering the sheets by a freely-mounted cam on the shaft 17 which is oscillated to engage a roller on an arm 93 fixed to the gripper shaft. The plunger 27, Fig. 4, is spring-pressed towards the recess 26, but is normally restrained by connection with a diaphragm 33 in a vacuum box 32 connected by a pipe 31 to an air passage in the arm 14 leading to a series of pin-holes which are normally closed by the sheet. If a sheet is absent or not registered correctly, the vacuum is broken, and the plunger 27 is permitted to move and engage the recess 26, thus holding the arm 14 locked. The shaft 17 is operated by an oscillating gear sector which is moved in one direction by a cam on the shaft 25 of the impression cylinder, and is returned by spring action. The grippers of the impression cylinder 11 are operated to receive the sheets by a pivoted cam 82, Fig. 7, which is normally maintained in a position to engage a roller 85 on an arm on the gripper shaft 86 by means of a cam 80 fixed to the shaft 17. When the arm 14 is moved to its inoperative position, the cam 82 is moved by a spring 91 to maintain the cam 82 out of the path of roller 85. Tripping-arrangements.-The bearings of the impression cylinder 11, Fig. 1, are normally moved against spring action, so as to bring the cylinder into printing position, by an eccentric 56 operated by an arm 55, connecting rod 54, and a tripping-device of known kind which permits the rod 54 to operate the eccentric 56 to move the cylinder 11 into and out of operation. The tripping-device 53 may be operated by a spring-controlled rod 52 to maintain the cylinder in its raised or inoperative position. The rod 52 is operable by a pedal 39 and lever 47. or it may be automatically operated by an eccentric 38 on shaft 17 and lever mechanism 40 - - 43 to cause the cylinder to be tripped when the arm 14 is held in inoperative position. If desired, the press may also be stopped automatically by opening a valve 63 to connect a suction pump to a valve 60 controlling air pressure in a cylinder 59 fitted with a plunger 58. The plunger 58 can engage a projection 57 on the cylinder shaft, and as the cylinder rotates the action on the plunger 58 causes the cylinder 59 to move about its pivot 64 and by means of a link 65 a lever 66 is operated to release a lever 77 which controls a tensioning pulley 71 of the driving-belt 70. As the belt 70 is slackened a brake 78 is applied simultaneously thereby stopping the machine. In the normal working of the press, the connecting-rod 54 as it moves downward to throw on the impression, engages a stem 62 and operates a valve 60 to connect the suction pipe to the cylinder 59 and thus cause the plunger 57 to be withdrawn, so that the machine is not stopped. Inking-apparatus.-When the bearings of cylinder 11, Fig. 1, are raised, the fountain roller of the inking-mechanism is tripped simultaneously by means of lever mechanism 107, 109, 110, 111, 112, of which one lever is connected to the bearings and pivoted to the machine frame.