Krupp Elastomertechnik GmbH (KEL) has developed a new duplex extrusion head for vehicle tire apex profiles. Featuring a new hydraulic lever locking system, the extrusion head is specially designed for apex production and thus considerably less expensive than the previously used standard extrusion heads.

Apex profiles are made from one or two different rubber compounds and are applied to the steel wire beads which hold the tire on the wheel rim. Special apex extrusion lines were already developed some time ago to allow the continuous production of these profiles and hot application to the beads without interim storage. KEL´s range also includes extrusion lines of this kind.

However, duplex extrusion heads with hydraulic hammer-head locking are still used to produce apex profiles, although they are really designed to make treads and sidewalls. As apex production requires significantly lower extruder output and lower locking forces, these heads are too big for the job and thus too expensive.

The new apex extrusion head from Krupp Elastomertechnik is much smaller and - with lower material and machining costs - considerably less expensive than standard units. The key innovation enabling the compact design is the new hydraulic locking system which applies the locking force of the hydraulic cylinders via flat, rotatable levers attached directly to the hammer head. Simple in design and inexpensive to manufacture, this locking system is currently the only one of its type on the market. Further features of KEL´s new extrusion head include optimal material flow, a cartridge system for quick die changing and a robust design. The first order for this new unit has already been supplied and a further is under discussion.