PRINTING ROLL CORE

摘要

A printing roll core for a printing roll comprising such a core (1) and a sleeve (22) which is provided to be mounted on the core from one end thereof and to be displaced along the core to and from working positions on the core by causing compressed air to flow out through passages (13a-13h) terminating in outlets distributed along the outer surface of the core, so that the sleeve from a state in which the sleeve tightly fits the core, when compressed air is not caused to flow through said outlets, may be expanded by causing air to flow through said outlets, so that the sleeve may be displaced along the core. The passages may be connected to a source of compressed air which preferably are common for said passages. In each of said passages is provided a valve (14) and each such valve includes an opening member (17, 19) having an outer portion (19) extending beyond the outer surface (7) of the exterior portion (2) of the core when the valve is closed and said outer portion is in its outer position, said outer portion being displaceable through outer mechanical action from said outer position to an inner position essentially interior of or coinciding with the outer surface of the core, wherein the valve is opened such that compressed air may flow out through the opening in the surface of the core, said mechanical action being performed by the sleeve as said sleeve is being mounted on the core, wherein the valves are successively opened as the sleeve is brought into contact with their outer portions and are closed again when the sleeve has passed the opening in question.