Improvement of an assembly drum designed for the production of self-supporting tyres

摘要

The drum assembly with variable diameter for manufacturing tire preform, comprises a cylindrical standing base (2) equipped with a circular grooves (3) disposed axially on a zone to receive outlines with thickness. The grooves have a circumferential incompressible elastic body (4), and the drum is led to a first standing diameter. A mechanical unit spreads the elastic body of the groove base radially to align an external surface of elastic body radially with the standing base of the drum. The drum assembly with variable diameter for manufacturing tire preform, comprises a cylindrical standing base (2) equipped with a circular grooves (3) disposed axially on a zone to receive outlines with thickness. The grooves have a circumferential incompressible elastic body (4), and the drum is led to a first standing diameter. A mechanical unit spreads the elastic body of the groove base radially to align an external surface of elastic body radially with the standing base of the drum. The elastic body tightens itself against the groove base with an effect of circumferentially elastic tensions when the drum is placed on a standing diameter greater than the first standing diameter. A transverse profile of elastic body is determined when the drum is placed at a second standing diameter greater than the first standing diameter. An external radial surface of the profile forms a cylindrical surface with the standing base of the drum. The mechanical unit is formed by rods, which are laid out circumferentially in the drum and the length of the rods are adjusted when the drum is led to its first standing diameter. Two ends of the rods are fixed with a circumferential bearing (1) of constant diameter and with an internal radial surface of the elastic body. The rod heads form a circumferential area. The rods and the elements form the surface of variable diameter slide freely with respect to each other.