Patent GB-773438-A (GB)
Title: Improvements in or relating to printing machines
Inventor: SCHUENEMANN HANS-BERNHARD
IPC: B41F3/02
Filed: 1955-06-14
Abstract: 773,438. Printing-machines SCHNELLPRESSENFABRIK KOENIG & BAUER AKT.-GES. June 14, 1955, No. 17159/55. Class 100(2) A power-operated cylinder trip comprises two pivoted members adapted to actuate a tripping member, the pivoted members being at rest until tripping on or off is to be effected, and a blocking member effective to, permit one only of the pivoted members to engage the tripping member at a time. As applied to a printing couple comprising a forme cylinder 3 mounted in eccentric bearings 4 (or in cam-operated sliding- block bearings), and an impression cylinder mounted on a shaft 1, two pivoted 'arms 17, 18, free to rotate on a control shaft 8, are linked at 21, 22 to a lever 23 having a roller 25 to follow a cam 2 on the shaft 1; the lever 23, and with it the whole tripping mechanism, is normally held at rest by a pawl 24 spring-biased to work further under the lever 23 until the roller 25 is clear of the cam 2 after two or more revolutions. Pawls 19, 20 on the arms 17, 18 are each sufficiently wide to engage two adjacent notched discs 10, 13 mounted between the arms 17, 18 and respectively fixed to, and free to rotate on, the shaft 8 which also has fixed thereto cranks 7 connected to the eccentric bearings 4 by links 5 adjustable by tumbuckles 6; one at least of the cranks 7 engages stops 9, 26 defining "pressure on" and "pressure off", the cranks 7 in the former position being just over-centre with respect to the links 5. The disc 10 has two notches 11, 12 into which the pawls 19, 20 may drop only when one of the notches 14, 15 in the disc 13 is in register therewith: with the parts in the "pressure on" position shown, upon withdrawal of'the pawl 24 the roller 25 drops, into the trough of the cam 2 and arms 17, 18 rotate respectively anti-clockwise and clockwise; as soon as the pawl 19 rides out of the notches 11; 14 the spring 16 rotates the disc 13 to bring its notch 15 into register with notch 12 in the disc 10, the notches 11, 14 being thus separated to prevent re-engagement of the pawl 19; at the low part of the cam 2 the pawl 20 drops into the notches 12, 15 and, as the roller 25 rides up the cam incline, drives the disc 10, shaft 8, cranks 7 and bearings 4 anticlockwise to the "pressure off" position; the pawl 24 then brings the whole tripping mechanism to rest. Upon the next withdrawal of the pawl 24 the sequence is repeated with the functions of the respective parts interchanged: the spring 16 separates the notches 12, 15 and brings notches 11, 14 once more into coincidence, and the cranks 7 and bearings 4 are returned clockwise to the "pressure on" position shown. When the pressure is tripped "off", the stop 26 may be turned aside, and to enable the forme cylinder 3 to be rolled out the cranks 7 and bearings 4 may be rotated further anti-clockwise, e.g. by a handwheel 27 movable axially against a spring to bring gears 29 on its shaft into mesh with reduction gears 30 to rotate the bearings 4; alternatively the handwheel may be provided on the shaft 8. The pawl 24 may be connected to a push-button mechanically, or as shown electrically, the circuit of the magnet 33 including contacts 31 which prevent actuation when the roller 25 is already over the low part of the cam 2; the contacts 31 may be replaced by a second pawl just below the pawl 24, which supports the lever 23 until withdrawn shortly before the beginning of the cam trough reaches the roller 25, a holding relay being included in the circuit of the magnet 33 to ensure that the pawl 24 does not re-engage until the tripping mechanism has operated. A double-pole changeover switch 32 may be provided to divide the electrical circuits for "pressure on" and "pressure off", and circuit arrangements are described for a press having a number of printing units which trip themselves "off" in succession in response to a single impulse from the "pressure off" button or a mis-feed contact on any one of them, and then operate a relay to stop the press. Each arm 17, 18 may have its own lever 23, cam 2, and pawl 24, the cams being such that to release the disc 13 each lever makes a second slight downward movement immediately after its operative movement.