Holding unit for mounting and aligning printing plates

Claim 1

A holding unit for mounting and aligning printing plates on the printing cylinder of a printing machine, said cylinder having a longitudinal axis, opposed end faces and a coaxial shaft with opposed coaxial shaft end portions projecting beyond the end faces; said holding unit comprising a straight rail adapted to parallel said cylinder in overlying relation thereto, said rail having opposed end portions, a pair of end sections engaged with said opposed end portions of said rail and extending generally laterally therefrom for overlying said end faces, said end sections each including a shaft-engaging structure configured to receive the corresponding shaft end portion, to self-center on the corresponding shaft end portion upon the shaft end portion being fully received therein, thereby positioning the rail of the holding unit parallel to the longitudinal axis of the cylinder, said rail including releasable plate securing means therealong for selective retention of printing plates on said rail for alignment on a cylinder, said releasable plate securing means being adapted to cooperate with complementary means on the plates to be mounted, said plate securing means and said complementary means comprising interengaging projections and recesses, said shaft-engaging structure of each end section comprising a pair of opposed members positionable to opposite sides of the corresponding shaft end portion, at least one of said members being mounted for movement, relative to the other member, toward and away from the corresponding shaft end portion for engagement and enclosure of the corresponding shaft end portion therebetween.