Electric Screw Jack Actuators may be used individually or in multiple arrangements . There are no “ standard “ travel lengths and each Worm Gear Screw Jack is built to specification . The jack housings are made of ductile iron and proportioned to support the rated capacity of the unit . models have aluminum housings . This is jack incorporates an alloy steel worm which drives a high strength bronze worm gear ( drive sleeve ) .
The worm shaft is supported 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 lifting screw to translate or rotate , depending upon jack configuration .