NL7701687A - Assembly drum for large size vehicle tyres - has doubled inflatable membranes bonding carcase layers against high shoulders - Google Patents

Abstract

A first pneumatically operated arrangement turns over some carcase reinforcing layers on to the drum and a second similar device turns the edges of the layers of the carcase itself, over the cores of the beads which are positioned against the shoulders of the assembly drum. The second pneumatic arrangement includes circular discs which can be displaced relatively to the drum in two directions, from a position within the drum to one outside it, and vice versa. An inflatable bladder is secured to and folded back against the outer radial surface of each disc by two beads along its edges, locked at a fixed distance apart. The membrane forming the bladder is unstretchable, having reinforcements extending from one bead to the other. The peripheral surface of the disc has the form of a truncated cone tapering to a smaller dia. outwards from the centre line of the drum. In the deflated condition, the membrane is thus held against the surface of the disc whilst when inflated it presses against the drum with a sufficient axial force to hold the edge zones of the carcase layers permanently against the outer surfaces of the carcases between the two bead cores. The carcase layers are automatically turned inside out and pushed on to the drum in a single operation. The layers are in the form of a continuous ring, ensuring that the cords in the layers are always accurately parallel to each other, and at the end of the operation, the layers are centralised accurately, relatively to the medium plane of the drum.