Abstract: Clamping apparatus is provided for holding thin flexible printing plates in position on a press cylinder. In some embodiments, shim members are attached to the outer periphery of the press cylinder for accurately radially positioning the printing plates with respect to the surface of the press cylinder. A clamping assembly is provided separately from and at a spacing from the shim members for releasably clamping one edge of the printing plate while the other edge of the printing plate is engaged over one of the edge portions of the shim member. The shim members and the clamping assembly are independently and separately attachable to the press cylinder so that the shim members can remain in position while printing plates are exchanged, as well as during removal and/or adjustment of the clamping assembly. A pair of symmetrically arranged lock bars are hingedly mounted for selective engagement with detent portions of the printing plates to accommodate reversal of the clamping direction.

Abstract: A clamping apparatus is provided for holding thin flexible printing plates, especially Mylar printing plates, in position on a press cylinder. A metallic rigid clamp body is provided which is attachable to the press cylinder in a gap or groove formed between facing ends of plate supporting shims and/or edges of a groove formed in the press cylinder. A pivot bar having a serrated clamping edge is pivotally supported in the clamp body for cooperation with a fixed facing clamping surface of the clamp body to clamp the leading edge of the "Mylar" plate. A "Mylar" spring is provided for providing a continuous light biasing force on the pivot bar in the clamping direction. The clamping action of the pivot bar is by way of camming action and engagement of the serrated surface into the "Mylar" or other printing plate material, such that movement of the plate in a direction out of the clamping space tends to increase the clamping force of the pivot bar.

Abstract: Clamping apparatus is provided for clamping thin flexible printing plates in position on a press cylinder. A continuously spring biased rigid clamping member is engageable with a bent over portion of the trailing edge of the printing plate to clamp the same against the circumference of a printing press cylinder. In order to accommodate loading and unloading of printing plates on the clamping member, retaining straps are attached to the clamping member, which retaining straps are engageable with a release bar detent to lock the straps and clamping bar in a non-clamping position against the force of the clamping springs. The release bar is continuously spring biased to a locking position so that whenever the clamping bar is moved to the non-clamping position, the same is locked in said position.