Patent ID: 6360802
Filing Date: 2002-03-26
Classification: B29D

Abstract:
A unistage drum for building tires (2) comprising a carcass (3) having two beads (7); the drum (1) comprising a cylindrical central body (17), and two half-drums (13) located on opposite sides of the central body (17) and moved in opposite directions along a common axis (9) by central actuating means (11); each half-drum (13) comprising a ring of sectors (43a), and first actuating means for moving said sectors (43a) in a substantially radial direction with respect to said axis (9) and to and from an expanded position to clamp a respective bead (7) in a relative given axial position (64) along the relative half-drum (13); wherein each said sector (43a) comprises a first and a second block (49,50), of which said first block (49) cooperates with a relative said bead (7) in said expanded position, and said second block (50) comprises a cylindrical outer surface (55); and second actuating means (33,37) for moving each said second block (50), with respect to the relative fit block (49), to and from an outer position in which each second block (50) projects radially outwards with respect to the relative first block (49) to define a relative portion of an annular shoulder (56) located between the given said axial position (64) and the relative said outer surface (55), and in a position adjacent to the relative given said axial position (64), wherein each said first block (49) is defied, towards the relative second block (50), by a first inclined surface (52) defining, with the first inclined surfaces (52) of die other first blocks (49) of said sectors (43a) in said ring, a substantially truncated-cone-shaped surface coaxial with said axis (9) and to which die second blocks (50) of the sectors (43a) in said ring are mounded to slide to and from said expanded position.