Chucking arrangement for hollow cores, particularly for newsprint rolls and the like

Claim 1

Chucking arrangement for cores (16) adapted to hold rolls of material thereon comprising a mandrel having a conical chucking head (9) formed with a predetermined angle of inclination; chucking jaws (2) surrounding the chucking head and adapted to be spread apart upon axial shifting of the conical chucking head; the chucking jaws (2) having a cylindrical outer surface (14) corresponding substantially to the nominal diameter of the inner opening of the core with which the chucking arrangement is to be used, and a radially extending rim (15) adapted to engage the end surface of the core (16); the inner surfaces of the chucking jaws being formed with three axially sequentially arranged conical surfaces (5, 6, 7), the outer ones (5, 7) having an angle of inclination of said predetermined angle and the middle one (6) having a lesser inclination than the other two; an offset (8) separating the middle one (6) of the conical surfaces from the innermost conical surface (7); and a shoulder (10) corresponding to the offset (8) formed on the chucking head, the offset abutting the shoulder when the chucking head is unloaded and not engaging a core, and, upon entering the chucking arrangement into a core, the inner surface of the core tipping the jaws to release the offset (8) from the shoulder (10) and engage the surfaces (5, 7) of predetermined inclination on the jaws with the conical surface (9) on the chucking head having said pre-determined inclination to engage the cylindrical outer surfaces (14) of the jaws with the inner surface of the core (16).