Abstract: An electric pulse tube expander for a bed with a vertical guide and horizontal guides mounted thereon. An electrode is movably mounted on the vertical guide. Mounted on the horizontal guides are drives for moving the electrode in vertical and horizontal planes. The drives include electric motors, reducers and mechanisms for setting the distance of movement of the electrode. Each of the mechanisms comprises a reducer whose drive gear is kinematically coupled to a lead screw, whereas its driven gear has an arm affixed to, and extending from, its shaft. The arm periodically interacts with a limit switch of a tube expander control system.