All jacton worm gear screw jacks lifting screw designs with three types, they are worm gear screw jack translating screw design, non-rotating screw design and rotating screw design.
Translating Screw Jack: A drives worm shaft acts on an internal bronze worm gear, which in turn drives a lifting screw to extend or retract. As the lifting screw translates through the jack housing, inherent screw rotation is prevented by an attached load, full guidances or mounting structure that is anchored to resist rotation. The lifting screw will move linearly through the housing to push or pull the load.
Note: The lifting screw of a translating screw jack must be attached to the load which prevents the lifting screw from rotating. Otherwise, the lifting screw and the load will turn and not translate. There are upright translating machine screw jack, inverted translating machine screw jack, upright translating ball screw jack, inverted translating ball screw jack.
Non Rotating Screw Jack: Also called keyed screw jack, anti rotation screw jack. A non rotating screw jack can prevent lifting screw rotation, which has milled keyway along the length of the lifting screw. A matching key is fastened to the cover of the screw jack, which will eliminate jack screw rotation. The keyway in the screw causes greater than normal wear on the internal drive worm gear threads, somewhat reducing screw jack lifespan.
Note: JTB series and JTD series ball screw jacks non rotating screw jack by square protect tube with square nut. There are upright keyed machine screw jack, inverted keyed machine screw jack, upright keyed ball screw jack, inverted keyed ball screw jack.
Rotating Screw Jack: A rotating screw jack has a lifting screw that moves a bronze travel nut as it turns. Features a lifting screw keyed to the internal bronze worm gear as a single unit, forcing the lifting screw to rotate, but not translate. A travel nut, attached to the load, is driven by the rotation of the lifting screw. This type of jack is ideal for applications that cannot accommodate a screw protective tube or that require a flush mount. There are upright rotating machine screw jack, inverted rotating machine screw jack, upright rotating ball screw jack, inverted rotating ball screw jack.