A. A driven worm shaft acts on an internal worm gear, which in turn drives a lifting screw to
    extend or retract. As the lifting screw translates through cast iron housing,then worm gear
    and lifting screw rotate together.When the lifting screw is held to prevent rotation,the lifting
    screw will move linearly through the cast iron housing to move the load.

Q: What is keyed screw jack?

A: Some loads don’t prevent lifting screw rotation. These applications require a keyed screw
     jack. A key, fixed to the jack housing and inserted into a keyway milled into the lifting
     screw, forces the lifting screw to translate without rotating.

Q: What is rotating screw jack?

A: A lifting screw keyed to the worm gear as a single unit, forcing the lifting screw to
     rotate,but not translate. A traveling nut, attached to the load, is driven by the rotation of the
     lifting screw. This type jack is ideal for applications that can not accommodate a screw
     protection tube and save enough mounting space.

Trapezoidal Screw Jack Features:

1. Model: RN-0.5T, RN-1T, RN-2T, RN-3T, RN-5T, RN-10T, RN-15T, RN-20T, RN-30T,
                RN-40T, RN-50T, RN-100T
2. Function: precisely controlled lifting, lowering, pushing, pulling and rolling movements
3. Self locking trapezoidal screw: Heavy duty, precision accuracy, low efficiency, use
                                                          infrequently
4. Arrangement: single units, in pairs or multiple jacks systems, fully synchronization
5. Power Source: electrically, manually or both