Keyed Ball screw jacks is supplied with a device that prevents rotation of the lift shaft. Anti-rotation is accomplished by a square guide attached to the screw translating inside a square stem cover attached to the jack. The square stem tube is supplied with lube fittings.
A Inverted translating jack has a lifting shaft that moves through the gear box. The lift shaft extends out from the bottom of the worm screw jack. A nut is integrated with the worm gear such that the worm gear and nut rotate together. When the lift shaft is held to prevent rotation, the lift shaft will move linearly through the gear box to move the load.