ROSTA oscillating drive heads type ST are flexible joints transmitting the acceleration forces from eccentric drive to the oscillating machine part - free of play, silently, reliably and without requiring maintenance. The common maintenance problems which are characteristic of these drive components are thus eliminated.The inner square section (core) and the trough are joined together by a so-called "fork". The outer housing is screwed to the slider crank rod and locked. Right- or left-hand threads are available, which allows the crank length to be adjusted easily.The drive heads up to type ST 45 have got an aluminium housing and core; type ST 50 has a housing made of SC iron and an aluminium core; ST 60 and ST 80 have an SC iron housing and a steel core.