Abstract: A preparatory station for pre-forming bar assemblies intended for use in conjunction with multiple extrusion head for producing rubber profiles for tread strips of automobile tires includes a plurality of chambers receiving said bar assemblies from said extruder head and for accommodating replacement assemblies, means being provided for heating the accommodation chambers, and further including arrangements for ejecting the pre-forming bar assemblies from the extrusion head and for removing the splicing or jointing bar assemblies and the profile bar assemblies from the pre-forming bar assemblies.

Abstract: An extrusion head suitable for producing tread strips for automotive vehicle tires from a plurality of rubber mixtures comprising a central head portion, upper and lower head portions disposed one on each side of said central head portion, said upper head portion and said central head portion and said lower head portion and said central head portion jointly defining at least two flow channels therebetween said flow channels being disposed above one another in a vertical plane, hydraulic means for pivoting each of said upper and lower head portions relative to said central head portion, said upper and lower head portions each including lateral portions extending substantially parallel to the direction of flow of said rubber mixtures through said head, hydraulically actuated locking means mounted on each said lateral portion and displaceable laterally outwardly in a direction substantially at right angles to said direction of flow, said locking means including locking members engageable with each said lateral p

Abstract: An extrusion head comprising at least one fixed head portion and at least one displaceable head portion pivotable into and out of an operative position includes means for filtering material being extruded and means for effecting change-over of the filter. The means for effecting the change-over includes at least two perforated plates displaceable on guide means in a direction generally at right angles to that of the extruded material. The at least one pivotable head portion includes a pressure surface which, in the operative position, abuts against the perforated plates thereby retaining the plates in position and sealing them against leakage of the extruded material.

Abstract: An extrusion head for producing, for example, tread strips for vehicle tires comprises a stationary central portion and two pivotable outer portions. Between each outer portion and the central portion, in the operative position of the head, insert members are interposed. Flow channels for the different materials used to make the tread strip and defined between the insert members and the central and outer portions of the head. The insert members are made displaceable by being detachably affixed to push-rods which are hydraulically, pneumatically or mechanically actuated. This provides for movement of the insert members, when the outer portions are pivoted away from the central portion, into a position which permits unhindered access to all sides of the insert members and permits the rapid cleaning and/or replacement thereof.