Abstract: Apparatus for printing press cylinders for releasably retaining printing plates. A printing plate locking bar is utilized in conjunction with a base member, the base member being fixed to a press cylinder construction and a locking bar being slidably secured thereto, thus adapted for sliding in a direction transverse to the longitudinal axis of the locking bar. Latching means is provided for releasably latching the locking bar in a particular position for printing plate removal and replacement. Spring means are supplied to spring-tension the printing plate so mounted, once the latching means is unlatched. Additional latching means may be provided for enabling the positive securement of the locking bar relative to such base member, through additional latch structure, where the plate is to be positively locked in its intended taut condition.

Abstract: Press cylinder structure for securing a printing plate over the cylinder's saddle. This saddle includes a first longitudinal edge permissably provided with a printing plate retainer bar, and the opposite edge of the saddle being spaced from an independent, movable, tensioned, printing-plate locking bar. Such locking bar is spring-loaded relative to the saddle, and is provided with registry orientation means. The locking bar is movable inwardly toward the saddle so as to facilitate printing plate, edge mounting onto the locking bar. Thereafter, the locking bar is urgeable outwardly with respect to the saddle so that tension may be applied to the plate. In the inward progress of the locking bar relative to the saddle, means are provided for releasably fixing the disposition of the locking bar relative to the press cylinder so that a printing plate disposed on the saddle and engagement thereof by the locking bar can be released.