Joyce worm gear ball screw jacks lift and precisely position loads up to 50-tons. Upright or inverted jacks operate at full capacity in tension or compression. Select from standard lead (WB, WBL) and high lead (HWB, HWBL) models to meet your travel speed and ball nut life requirements. These ball screw jacks require up to two-thirds less input torque to move the load than similarly rated machine screw jacks. They require a brake motor or external locking device to hold position.