Abstract: The present drum can find application mainly for assembling large-size tire casings.The drum comprises sectors with shoulders provided with a drive for their radial movement. The drive incorporates slide-blocks arranged concentrically with each other on a shaft axially movable therealong. The slide-blocks are articulated, through levers, with the sectors. The midpoint of one of the levers of each slide-block is articulated with the shaft through the link which is half as long as the lever.The shoulders are provided with a mechanism for their relative movement with respect to the sector. The mechanism is made as a cam associated with the lever of radial movement drive of the sector. The cam is adapted to engage one of the toothed segments articulated to the sector. The toothed segments are kinematically associated with each other and are in mesh with the respective toothed racks connected to the shoulders, so that the toothed segment engages the cam through the agency of a pin provided on the cam.

Abstract: The tire-building drum comprises alternate drum sectors with fixedly and movably mounted shoulders and mechanisms for moving said drum sectors. Each of these mechanisms consists of two parts having annular slides, which are connected to a screw drive, and levers, which are articulated to the drum sectors and the slides and which have toothed sectors arranged in constant mesh with each other for the purpose of inter-connecting the parts in each of the mechanisms for moving the drum sectors. The slides are mounted coaxially on the drum hub and are adapted to move together and separately in mutually opposite directions. This enables the drum sectors to move only radially and decreases the axial dimensions of the drum.