Printing press cylinder support and control

Claim 1

In a printing press, in combination, a main frame, cooperable plate, blanket and impression cylinders each having journals, bushing means supported for rotation in said main frame and eccentrically supporting said blanket cylinder journals, trip mechanism connected to said bushing means and selectively operable to rotate said bushing means and thereby move saId blanket cylinder to and from a printing position relative to said impression cylinder, radially expandable pad means in said bushing means for circumferentially restraining and radially, compressively stressing said bushings relative to said main frame when activated by an elevated fluid pressure, fluid containing circuit means connected to said pad means in fluid pressure conducting relation, intensifier means connected to said fluid circuit means and adapted when activated to generate an elevated fluid pressure in said fluid circuit means, sheet detector means adapted to produce an output signal indicative of the presence or absence of a sheet to be printed, and control means responsive to said sheet detector means for activating said trip mechanism and said expandable pad means in reverse sequence upon the detection of the presence or absence, respectively, of a sheet to be printed, said control means including a first control element normally responsive to a signal from said detector means for activating said trip mechanism, a second control element normally responsive to a signal from said detector means for simultaneously activating said intensifier means, a third, normally closed control element connected between said trip mechanism and said second control element and operable upon detection of the presence of a sheet to prevent activation of said intensifier means by said second control element until said trip mechanism has moved the blanket cylinder to its printing position, and a fourth, pressure responsive control element connected between said fluid circuit means and said first control element and operable when detection of the absence of a sheet to prevent said first control element from activating said trip mechanism to move said blanket cylinder from its printing position until said intensifier means is deactivated and the elevated pressure in said fluid circuit means is relieved.