Quick-acting clamping device

A device for the rapid clamping of flexible printing plates on the rotatable printing cylinder of rotating printing presses, which cylinder has at least one longitudinally-extending groove opening onto a circumferential surface thereof, which groove has a base and a front and rear side, with respect to the direction of rotation thereof, of the type which includes at least one support bar positioned adjacent to the front side of said groove and bolted to the base of said groove, said support bar having a plate attachment arm to which a front end, with respect to the direction of rotation, of a printing plate can be clamped, at least one clamping arm lying in said groove opposite to said support bar and being pivotably mounted in said groove, said clamping arm having a bearing arm to which is secured a plate attachment arm which extends generally normally therefrom and to which a rear end, with respect to the direction of rotation, of a printing plate can be clamped, at least one pressure spring coupled to said clamping arm of biasely acting upon said clamping arm in a direction towards said front side of said groove which represents the clamping direction of said clamping arm, said spring extending approximately in the direction of the plate attachment arm of said clamping arm, and an adjusting device for actuating said plate attachment arm of said clamping arm against the force of said spring the improvement comprising:

• said support bar and said clamping arm each having at least one clamping spring secured to said plate attachment arm thereof for gripping the front and rear end of said printing plate, respectively, said plate attachments arms each having a slider slidably mounted thereon and disposed for cooperative engagement with the associated spring of said plate attachment arm which slider is movable between a clamping position in which it moves at least a portion of said associated clamping spring into biased engagement with an opposing surface of said plate attachment arm to which it is secured and a non-clamping position, in which it moves at least a portion of said associated clamping string into a non-engaging position relative to said opposing surface of said plate attachment arm to which it is secured, the respective plate attachment arms of said support bar and clamping arm being separate by a space defining a channel, said sliders each having an actuating claw secured thereto which has a free end disposed in said channel on which is a toothing and wherein said device additionally includes a key having a beard which may be inserted into said channel and brought into separate contact with said toothing of each of said free ends of said claws whereupon turning of said key effects movement of said sliders between said clamping and non-clamping position, so as to, in turn, permit movement of said portions of said clamping springs into and out of engagement with said opposing surface of said support bar and clamping arm, respectively, independently of each other and of any pivotal movement of said clamping arm.