Patent GB-925203-A (GB)
Title: Improvements in or relating to offset rotary printing machines
Inventor: GATES ALBERT GEORGE RONALD
IPC: B41L25/00
Filed: 1960-02-01
Abstract: 925,203. Damping apparatus for printing machines. GESTETNER Ltd. Jan. 30, 1961 [Feb. 1, 1960], No. 3554/60. Class 100 (2). In an offset rotary printing machine the apparatus for dampening the plate on the plate cylinder 1, Fig. 1, is movable between a damping position and an out-of-the-way position and comprises two damping rollers 19, 20, a reservoir 27 for dampening liquid and wick means for leading liquid from the reservoir to the surface of each roller. The arrangement of the apparatus is such that when in its damping position, the rollers engage the plate-the roller 20 being spring-urged into such engagement-at angularly spaced positions therearound and the leading roller 19 rotates at a lower speed than the trailing roller 20, and when in its out-of-theway position, both rollers are spaced from the plate cylinder. The apparatus is mounted on a rotatable shaft 2 extending between two spaced side members 3 rigidly connected by cross-bars 4 and secured to the machine by arms 5. The apparatus comprises two side plates 6 which are parallel to the members 3 and are mounted on the shaft 2, the latter carrying at one end a handle 7 by which the shaft may be rotated to move the apparatus to the damping position, Fig. 3, against springs 8 connected between each plate 6 and the adjacent member 3 which normally bias the apparatus to the out-of-the way position of Fig. 4. The handle 7 carries a catch for locking the apparatus in its out-of-the-way position, such catch comprising a locking member 9 extending alongside the handle and having at one end a finger-piece 10 and at the other a locking peg 11 engaged in a slot 12 in the adjacent member 3. The member 9 also has two slots 13 through which pass pins 14 carried by a plate 15 on the side of the handle opposite to the member 9, and a peg 16 projecting into a slot 17 in the handle housing a compression spring 18. When the handle 7 is raised to move the apparatus into its out-of-the-way position, the spring 18 pressing on the peg 16 moves the member 9 in a direction towards the shaft 2 so that the peg 11 engages the upper branch of the slot 12, thus locking the apparatus. For release purposes the member 9 is retracted by actuation of the finger-piece 10. Each of the rollers 19, 20 has an axial bore 21 in which fits a tapered pin 22 journalled rotatably in the appropriate sideplate 6. The plates are connected by a crossmember 23 and screws 24, removal of the latter allowing the plates 6 to be moved apart to withdraw the pins 22 so that the rollers may be replaced or interchanged. At one end of the rollers each pin 22 carries a sprocket 25 and an endless chain 26 engages the sprockets so that one roller drives the other. The roller 19 rotates at a lower speed than the roller 20, the sprockets 25 associated with the rollers 19 and 20 having nine and eight teeth, respectively. Above the side-plates 6 the apparatus comprises a damping liquid reservoir 27 surmounting a wick 29 and a sponge pad 28, the liquid passing from the reservoir to the pad through an aperture 30. If desired, the wick may be dispensed with. The reservoir carries at each side two pins 31 which pass through guide slots 32 in the adjacent side member 3 and which control the reservoir when the apparatus is moved relatively to the side members. The reservoir also carries a roller 33 resting on the plates 6 such that when the apparatus moves to its out-of-the-way position the plates exert a camming action on the reservoir and the latter moves relatively to the plates and the rollers carried thereby, such movement being guided by the pins 31 in the slots 32. The arrangement is such that, in the out-of-the-way position, the pad 28 is out of contact with the rollers and the base of the reservoir slopes downwardly away from the aperture 30, whilst in the damping position, the pad engages the rollers and the reservoir is inclined so that the reservoir slopes towards the aperture. The rollers 19, 20 may be made of, or have a covering of, rubber or felt and they may be of similar or dissimilar form.