Worm gear screw jack (translating screw)
Ondrives

Ondrives offer a range of screwjack actuators produced in many standard models with a wide range of capabilities, and there is a standard model for almost any requirement. Operated manually or by motor units screwjack actuators can be used singly, in tandem or in multiple arrangements. Since most capacities have a uniform lifting speed, added economy can be realised in raising unevenly distributed loads by operating the different capacities in unison. Both rotating and translating, upright and inverted models are available in four different sizes.

They have many advantages -

Positive, mechanical positioning
Anti-backlash feature (optional)
Capacities from 5kN to 100kN
Worm gear ratios from 5:1 to 24:1
Ambient temperature range -20ºC to +90ºC
Bottom pipe protects lifting screw threads
Provided that a screwjack is correctly installed and maintained, the screw life will normally exceed the calculated gear life.
Self-locking
Secondary guide increases lifting screw lateral rigidity aiding screw guidance and improving side load resilience
Bellows boot protects the screw from dust, dirt, moisture and corrosive contaminants
A ballscrew version is available which offers higher cycles.