Abstract: An unvulcanized tread strip for a pneumatic vehicle tire. The tread strip includes two or more superimposed layers. In order to improve the adhesion of these layers, adjacent layers of the tread strip are provided with a plurality of projections and corresponding recesses which positively intermesh with one another.

Abstract: An extrusion die having pivotally mounted parts disposed at the die outlet and pivotal locking members for latching the pivotal parts closed.

Abstract: An extruder head for producing flat cohesive profiled strips from resilient mixtures of differing composition, such as mixtures of rubber or synthetic material, and especially for manufacturing uncured tread strips for pneumatic tires having a two-ply central portion and two similar edge portions. The extruder head includes two extruders which are disposed at an acute angle next to or above one another, and feed a common extrusion nozzle via a preform die or member having flow channel which extend one above the other. The extruder head also has a third extruder which conveys the mixture for the edge portions and is connected to the preform die at a greater angle than are the aforementioned extruders.

Abstract: An extruder which serves for kneading and extruding rubber and synthetic material mixtures. The extruder is equipped with a rotatably mounted screw, and pin bodies which project into the interior of the housing. These pin bodies can be damaged, and in particular can be bent or even broken. In order to quickly determine these failures, and possibly to even determine deformed pin bodies, the latter are incorporated into an electrical monitoring circuit. The pin bodies are provided with electrical inserts which influence the monitoring circuit when deformations or breakage of the pin bodies occur, in order in this way to transmit a signal or even electrically switch off the extruder. In place of the electrical inserts, photo conductors can be used, the optical conductivity of which can be utilized for determining the aforementioned damages.