Background of the Screw Extruder (2)

Occasionally there is a desire to be able to vary the pin depth rapidly and without consuming too much time between zero and maximum for reasons relating to the process. Pin extruders for working rubber mixtures which are not preheated have attained great economical importance when constructed in accordance with German Patent 22 35 784. The mechanical fine pin adjustment operating with spiral plates is rarely used, however, for reasons of cost. The movement of, for example, eight pins in a single pin plane also requires considerable power and thus causes great wear on the adjusting means. For the numerous pin planes, amounting to about six to sixteen planes, this adjustment is furthermore quite time-consuming. Therefore there is a need for a rapid adjustment of the pins for the purpose of losing as little time as possible when the screw has to be replaced for technical reasons with one of a different shape, or because it is worn, or for cleaning purposes.