These worm gear screw jacks are very precision and reliability, it could meet all of the necessary protection, cost-efficiency, and durability mandates of your application. High strength bronze worm gear is used, the payloads from 0.5T to 100T . A total of 11 sizes can be found, each in a traveling nut version and a basic version.
Worm gear drive screw jack
Translating(traveling screw) and rotating (traveling nut) configurations
Electric Driven and Manual Operated both are available
Trapezoidal spindle (self-locking) and Ball Screw spindle (high efficiency) version
Design option: Regular, Anti-rotation, Anti-backlash or Basic safety nut
Standard and customized end fittings, installation options, and drive shaft
Worm Gear Screw Jack systems are ruggedly designed and stated in standard models with load handling capacities from 1/4 ton to 100 tons. They may be used individually or in multiple plans. There are no “standard” travel lengths and all Worm Gear Screw Jack systems are designed to specification.
The jack housings are made from ductile iron and proportioned to support the rated capacity of the unit. MJ, 1/4 ton, and 1/2 ton models have aluminium housings.
Each Worm Gear Screw Jack incorporates an alloy metal worm which drives a high strength bronze worm gear (drive sleeve). The worm shaft is backed on antifriction tapered roller bearings with exterior seals provided to prevent lack of lubrication (sealed radial bearings on the MJ, 1/4 , 1/2, and 1 ton systems). The drive sleeve is supported on antifriction tapered 
roller or ball thrust bearings. Rotation of the drive sleeve causes the lifting screw to translate or rotate, dependant on jack configuration.
The Inch and Metric Worm Gear Machine Screw Jacks incorporate an alloy or stainless steel worm which drives a higher strength bronze worm gear (drive sleeve). The worm shaft is backed on anti-friction tapered roller bearings with external seals provided to prevent loss of lubrication. The drive sleeve is supported on anti-friction tapered roller or ball thrust bearings. Rotation of the drive sleeve causes the thread lifting screw to translate or rotate, dependant on jack configuration.
The threads are precision formed, typically using Class 2-C (Centralizing) tolerances. Jack lift shaft Worm Gear Jack business lead tolerance is approximately ±0.004″ per foot.