It is a worm gear with shafts perpendicular to each other. It consists of a helical worm screw and a circular cogwheel. Some applications of this device are automatic doors or elevators systems, where motion in one direction and blocking the system by a limit switch are required. Besides, it is designed to transmit great stresses
WGCM Unité d'Etude d'un Modèle en Coupe à Engrenage à Vis sans Fin
It is a worm gear with shafts perpendicular to each other.