| 摘要 |
A lithographic printing press having the usual plate cylinder, blanket cylinder and impression cylinder in pressure engagement with one another, the bearings having at least a normal amount of play so that the journals are supported in normal elevated positions in the bearings depending upon the direction of the pressure vectors, at least the blanket and impression cylinders having phased gaps in the surfaces thereof, tending to cause cyclical, momentary loss of support accompanied by dropping of the blanket cylinder from the normal journal position in the bearing as the region of the gap is traversed, followed immediately by lifting of the blanket cylinder back to normal position resulting in cyclical impact. In order to prevent such dropping and lifting a cam is provided which extends coaxially about the bearing of the blanket cylinder on a line connecting the centers of the blanket and the impression cylinders, and a cam follower is rotationally secured to the blanket cylinder phased with the gap therein, the cam and cam follower serving to provide bridging support for the blanket cylinder during the time that the gap is being traversed, thereby to avoid cyclical impact. Where short, relatively thick stock is to be printed, the effective arcuate span of the cam and cam follower are increased to extend the bridging support over the non-printing area.
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