CARRY-IN METHOD AND DEVICE IN WHICH MATERIAL IS HARDLY LOST THROUGH DUPLEX TYPE EXTRUSION MOLDING PARTICULARLY FOR MANUFACTURING MOLDING BLANK FOR TRAVELLING SURFACE OR SIDE SURFACE OF CAR TIRE CONSISTING OF VARIOUS ELASTIC RUBBER OR PLASTIC MIXTURE

摘要

An apparatus for reducing wastage during the start-up phase of extrusion device used to produce extruded profiles such as tread strips for vehicle tires from a plurality of mixtures. Each of a plurality of extruders extrudes one component of the profile and is provided with its own drive motor. The outlets from the extruders communicate with a template member having flow channels formed therein which communicate with the outlet ends of the extruders and which lead into a common extrusion port. Pressure sensors are positioned adjacent to the outlet of each extruder. These pressure sensors and the drive motors for each extruder are operatively connected to a control device which has stored therein predetermined desired pressure levels for each extruder. The drive motors for the several extruders are actuated and the pressure of each is monitored and compared with the predetermined desired pressure for each extruder. When the pressure in a particular extruder reaches such desired pressure, the drive motor for that extruder is shut off. When the desired pressures have been reached in all of the extruders, the drive motor for all extruders are re-actuated simultaneously by the control device. Alternatively, the last extruder to reach the desired pressure can continue to operate and the drive motors for the other extruders re-actuated. In either event, wastage of material is greatly reduced.