Patent GB-943987-A (GB)
Title: Improvements in rotary printing machines
Inventor: THOMPSON FRANK SYDNEY
IPC: B41F13/32
Filed: 1961-09-21
Abstract: 943,987. Rotary printing machines; cylinder tripping. T. C. THOMPSON & SON Ltd. Aug. 31, 1962 [Sept. 21, 1961], No. 33773/61. Heading B6C. In a sheet-fed rotary printing machine of the type in which a plate cylinder is mounted to swing into and out of engagement with an impression cylinder mounted in fixed bearings the plate cylinder and inking rollers are mounted in a frame pivoted on the axis of an inking drum and means are provided to swing the frame to bring the plate cylinder into and out of engagement with the impression cylinder without disturbing the setting of the plate cylinder and the rollers. Means are also provided to adjust the pressure between the two cylinders. In the machine shown forme rollers b, b<SP>1</SP> and plate cylinder C<SP>1</SP> are rotatably mounted in a frame B pivotally mounted on a shaft a<SP>2</SP> which also mounts an inking drum A<SP>1</SP>. The latter is fed from a duct a by the usual rollers a<SP>10</SP>, a<SP>11</SP>, a<SP>12</SP> and a<SP>1</SP>. The cylinder C<SP>1</SP> is moved into and out of engagement with the impression cylinder C by rocking the frame B through a lever D which is mounted on a spindle d carried in the machine frame A. The spindle d also mounts an arm d<SP>1</SP> which has a roller d<SP>2</SP> engaging a slot in a forked bracket b<SP>2</SP> mounted on the plate cylinder shaft c. The impression cylinder is connected to the plate cylinder by an arm C<SP>2</SP> at each end of the cylinder each arm engaging an eccentric portion of the shaft c such that rotation of this shaft by the lever D and arm d<SP>1</SP> moves the cylinders towards or away from each other. Adjustment of pressure and alignment between the cylinders is effected by mounting the impression cylinder C on a shaft c<SP>2</SP> having an eccentric bush C<SP>3</SP> at each end. The bushes carry teeth engaged by worm-wheels c<SP>4</SP> rotation of which displaces the arms C<SP>2</SP> and consequently the frame B to vary the distance between the axes of the cylinder shaft c<SP>2</SP>, C<SP>2</SP>. When the cylinder C<SP>1</SP> is brought out of engagement with the impression cylinder C the inking of the plate cylinder may be interrupted by lifting the inking rollers b, b<SP>1</SP> therefrom and interrupting the ink supply to the feed roller a<SP>12</SP>. For this purpose a three-armed cam D<SP>1</SP> is pivoted on the frame B at each side of the machine having two cam surfaces d<SP>3</SP>, d<SP>31</SP> to engage respectively the levers b<SP>3</SP>, b<SP>31</SP> as the cam is rotated from position 1 in Fig. 2 to position 2 by a cam lever D<SP>2</SP> to lift the levers b<SP>3</SP>, b<SP>31</SP> to bring the inking rollers b, b<SP>1</SP> out of contact with the plate cylinder. In order to interrupt the ink supply to the roller a<SP>11</SP> one end of a rod a<SP>4</SP> is pivoted to the third arm of the cam D<SP>1</SP> the other end being pivoted to a pivoted link a<SP>5</SP> on the frame A, movement of the lever D<SP>2</SP> bringing the link a<SP>5</SP> into engagement with a rod a<SP>6</SP> depending from a cradle carrying the roller a<SP>11</SP> to arrest the movement of the cradle. The initial movement of the cam D<SP>1</SP> from position 1 to position 2 does not bring the link a<SP>5</SP> into engagement with the rod a<SP>6</SP> and the movement of the cam D<SP>1</SP> from position 2 to position 3 does not affect the movement of the rollers b, b<SP>1</SP> as a radial portion of the cam surfaces d<SP>3</SP>, d<SP>31</SP> engages the levers b<SP>3</SP>, b<SP>31</SP>. The pressure between the inking rollers b, b<SP>1</SP> and the drum A is adjusted by pivoting the levers b<SP>3</SP>, b<SP>31</SP> on eccentric lockable fulcrum pins b<SP>32</SP> mounted on the frame rotation of which pins by levers b<SP>33</SP> raises or lowers the rollers b, b<SP>1</SP>. Adjustment of the pressure between the rollers b, b<SP>1</SP> and the plate cylinder C<SP>1</SP> is obtained through eccentric lockable pins b<SP>6</SP> mounted in the former engaging the inner surface of each lever b<SP>3</SP>, b<SP>31</SP>. Rotation by levers b<SP>61</SP> against the action of springs b<SP>62</SP> causes the levers b<SP>3</SP>, b<SP>31</SP> to pivot about their fulcrums. The levers b<SP>3</SP>, b<SP>31</SP> may be rocked to bring the rollers b, 6<SP>1</SP> clear of both the inking drum A<SP>1</SP> and the plate cylinder C<SP>1</SP> for removal, by pins b<SP>51</SP> each on a pivoted shaft b<SP>52</SP> actuated by a control arm b<SP>5</SP> to cause the pin b<SP>51</SP> to engage the tail end b<SP>4</SP> of a lever.