Manual Screw Jack is composed of hand wheel or hand crank and a worm gear screw jack, which has intermittent precisely positioning and self-locking feature for no creeping down without brake mechanism or other locking systems, when manual ball screw jack, no self-locking feature, avoid ball screw back drive with attached load, which needs additional brake mechanism or other locking system 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.
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Hand operated screw jack for crank table
Hand Wheel Worm Gear Screw Jack