Hydraulic fast locking and loosening device for bearing assemblies of rolling-mill cylinders, and corresponding method of use

A roll bearing assembly comprising a roll with an end neck having a first portion, with a tapered external surface, and a second portion, at the external end of the roll neck, with a cylindrical external surface and adjacent to said first portion, and further comprising, from the internal end to the external end of the roll neck, an oil-film bearing fitted on said first portion, a spacer ring, a thrust bearing fitted on the second portion of the roll neck and contacting the spacer ring, a thrust ring fitted on the second portion of the roll neck and contacting the thrust bearing and a threaded lock ring fitted on said second portion of the roll neck and contacting the thrust ring, said thrust ring being provided with first engagement means on its outer surface for releasably engaging a roll bearing locking and loosening device for locking and loosening operations;

• wherein said first engagement means is suitable to be connected solidarily to a corresponding second engagement means provided on longitudinal arms of a locking and loosening device, such that said first and second engagement means are reciprocally engaged for fixing a hydraulic device to the roll bearing assembly in the course of both locking and loosening operations.