The ROSTA universal joints type AK are maintenance-free elastic joints which can be moved in any direction. They are used as universal joint supports for mounting or suspending gyratory screens, screening tables, tumbling oscillators, sorters and screening machines positively driven by eccentrics or freely oscillating with unbalanced drive. The types AK 27 until AK 100-4 have got housings made of SC iron, all the other sizes are made of welded steel structures. The types AK 15 to AK 50 have got aluminium square sections, the other sizes have steel cores