摘要 |
A tread band for vehicle tires is manufactured by conveying a primary elastomer material (4) through an extrusion path (11, 15) defined by a preforming channel (15) followed by an extrusion outlet (11) formed in a die (10). The preforming channel (15) is defined in a preforming device (9) comprising a drawer (12) operatively engaging a preformer (13). Formed in the drawer (12) is an auxiliary channel (17) the end length (17b) of which opens at right angles into the extrusion path (11, 15), close to the extrusion outlet (11). An auxiliary elastomer material (5) conveyed to the auxiliary feeding channel (17) is homogeneously distributed by a coating effect under the lower surface of the tread band (4a) crossing the extrusion outlet (11).
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