Hand wheel worm gear screw jack is composed of hand wheel or hand crank and a complete set worm gear screw jack with internal worm and worm gear sets, standard hand wheel or hand crank dimensions from 5" to 20" diameter, special hand wheel or hand crank dimensions required, please contact Lude Transmission engineers. When manual acme Screw Jack , machine screw jack, which has intermittent precisely positioning and self-locking feature for no creeping down without brake mechanism or other locking systems. But hand operated worm gear ball screw jack, no self-locking feature, avoid ball screw back drive with attached load, which needs additional brake or locking mechanism to prevent it creep.
When hand operated screw jack need precise position display, a range of digital position indicators are available. These digital position indicators measure the rotations of the input shaft and display corresponding position in the digital counter window. The display value per input shaft revolution is variable and is achieved through a series of gear reductions configured to accommodate different worm gear screw jack ratios, screw pitch and travel length.