FIELD: machine building.
SUBSTANCE: invention relates to a tyre building drum with a turn-up mechanism. Tyre building drum for building an unvulcanised tyre having rubber tyre components, including two beads, comprises a drum shaft and two bead holders arranged around the drum shaft, wherein the bead holders are mutually spaced apart in the axial direction of the drum shaft for supporting the tyre components at the location of the beads, expansion means for radially expanding the part of the tyre components situated between the bead holders, a turn-up mechanism for turning-up the part of the tyre components situated outside of the bead holders around the beads against the expanded part of the tyre components to form an unvulcanised tyre. Turn-up mechanism comprises a group of arms arranged on each side of the drum shaft outside of the bead holders. At a first end, the arms of each group are coupled to the drum shaft via an axially moveable arm support. Arms extend from the arm support towards the bead holders in radial planes equally distributed about the drum shaft, wherein the arms are arranged to be tilted in said radial planes about their coupling with the arm support between a low position and a high position. Each group of arms comprises primary arms and secondary arms interposed between the primary arms, wherein the primary arms and the secondary arms, at a second end opposite to the first end, are provided with primary pressing elements and secondary pressing elements, respectively, for exerting a pressing force onto the tyre components during the turning-up. Primary pressing elements are in a leading position, wherein the secondary arms are provided with actuators which are arranged for displacing the secondary pressing elements from an axially trailing position with respect to the axial position of the primary pressing elements in the leading position towards the same axial position as the primary pressing elements in the leading position.
EFFECT: invention provides an increase in the distribution of pressure of the turn-up mechanism along the components of the tyre.
22 cl, 12 dwg
