Proximity switches can be called proximity limit switches, proximity sensor switches or inductive proximity stroke end switches. Proximity switches are available for worm gear screw jack with translating screw only. Its features: proximity limit switches are inductive sensors with normally closed contact fitted on the protective tube and activated by the metallic ring fixed on the acme screw end. In case the screw jack is not stopped after the sensor activation, when the metallic ring moves away the sensor restores the original state (becomes deactivated). In case the limit switches are used to stop the screw jack, we recommend to provide for an electric connection in order to latch the signal and to prevent that the screw jack moves again in the same direction. Screw jacks with proximity limit switches are supplied with two sensors for the acme screw extreme positions. Extra switches for intermediate distances available on request.