Sheet feeding apparatus for printing presses

Abstract

A sheet feeding table has pull-type side lays and front lays. Mounted beneath the feeding table and nearer the front lays are suction drums spaced apart and rotated by a transversely extending drive shaft on which they are mounted. The shaft is driven through toothed wheels having relative axial movement with respect to each other. A cam plate rotates with the shaft and a pair of fixedly mounted rollers guide the cam plate and impart reciprocating motion to the shaft and the suction drums. The lateral shifting of the suction drums clears the sheet from the pull-type side lay for the successive sheet. Each drum has a suction piece sealed and biasedly positioned adjacent a portion of the inside peripheral surface of the drum which rotates thereby and brings the drum suction holes into communication with the suction chamber within the suction piece. The suction chamber is in communication with a vacuum supply and a control valve is interposed in the supply. The sheets are fed to an impression cylinder having front stops and a series of sheet grippers. The speed of the drums is raised somewhat excessively to convey the sheets against the front stop in the impression cylinder.

Dependencies are inferred from the claim text.