Process for manufacturing a multi-layered sole directly on the upper and machine operating with said process

A process for manufacturing a multi-layered sole directly on an upper employing a technique known as “direct injection on the upper”, by which soles (S) are made of a plastic material and consist of a plurality of layers with different colour, density, softness, said layers forming at least an external sole, called “outsole” (S1), an internal sole, called “insole” (S2) that adheres and extends only partially or totally on a surface of the upper (T), and an intermediate sole, called “midsole” (S3), that is intended to hold the other two above-said soles (S1, S2), said process providing for use of a single mould which is brought, when suitably equipped, in a well-defined sequence, in front of at least three distinct injectors (I1, I2, I3) in order to obtain, also in sequence, by at least a first moulding operation (P1) a lower portion of the sole, i.e. the “outsole” (S1), by at least a second moulding operation (P2) a upper part of the sole, i.e. the “insole” (S2) and by at least a third moulding operation (P3) the “midsole” (S3), wherein, said process

• employs the single mould consisting of a number of components removably connected to each other in order to be able to be suitably equipped with respect to the injector of the at least three distinct injectors (I1, I2, I3), which components comprise a support, rotating about an axis (X) of its central pin on which a radial arm, ending with a form related to the upper (T), and an opposite radial arm, ending with a disc, are removably hooked, two opposed side half-rings, two upper opposed half-rings and a base.