Method for Jointing a Layer of Material in Order to Produce a Green Tire

1 . A method for jointing an external layer of material to a base layer to produce a green tire, the green tire having an axis of revolution, the method comprising a step of applying the outer layer to the base layer, followed by a step of jointing the outer layer to the base layer, wherein the jointing step is done using a pressing element surrounding the outer layer and elastically deformable between an enlarged configuration and an outer-layer pressing configuration, in which the pressing element applies a radial pressure to the outer-layer, the jointing step comprising the following steps:

the passage of the pressing element from the enlarged configuration to the outer-layer pressing configuration, under the action of deformation means; and

the movement of the pressing element in the outer-layer pressing configuration, in the axial direction of the green tire, under the action of movement means.

2 . The method of claim 1 , wherein the pressing element delimits a closed outline of a given perimeter and is configured in such a way that the perimeter of its outline, when it is in the rest configuration, is less than the external perimeter of the base layer so that the pressing element in the outer-layer pressing configuration applies a radial compression force compressing the outer layer radially against the base layer.

3 . The method of claim 1 , further comprising a step in which the pressing element passes from the outer-layer pressing configuration into the enlarged configuration under the action of the deformation means.

4 . The method of claim 1 , while the pressing element is in the outer-layer pressing configuration, the deformation means are operated in such a way as to increase or decrease the pressure applied to the outer layer.

5 . The method of claim 1 , wherein use is made of two pressing elements, each being moved in the axial direction in opposite directions from an equatorial plane of the green tire.

6 . The method of claim 1 , wherein the pressing element is a helical spring having a circular axis.

7 . The method of claim 1 , wherein the deformation means are carried by a support frame mounted such that it can move in the axial direction of a rotary drum under the action of the movement means.

8 . The method of claim 1 , wherein the deformation means comprise pneumatic actuating cylinders that deform the pressing element.

9 . The method of claim 1 , wherein the pneumatic actuating cylinders are distributed around the pressing element, each activating an actuating cylinder rod of which one end is fixed to the pressing element so as to be able to enlarge the perimeter of the pressing element through elasticity.

10 . The method of claim 1 , wherein the end of the rod of each actuating cylinder comprises a cavity to house the pressing element, having a retaining shape for retention of the pressing element, leaving the pressing element free to rotate within the cavity.

11 . A method of manufacturing a tire comprising a jointing method of claim 1 .