Screw-jack – ideal for linear transfer of cargo from one point to another. The main components – a gear (worm or tapered), trapezoidal screw and nut (or a pair of ball screws). The drive uses asynchronous or other type of motor and flywheel for manual transmission. Jackscrew can be done in two ways: 1) to the lead screw, 2) running nut. Ram can be equipped with additional details, such as corrugated casing, limit switches, lubricating devices, swivel tip, drive cross-pieces for the free suspension jack and many other components with uetom for what purpose is the jackscrew. In contrast to the hydraulic actuator is easier to work and for maintenance, requires less qualified staff. There's a number of models with different characteristics on capacity up to 1000 kN! System may be used jacks for 2 pieces, 4 pieces, 6 pieces, etc. For example screw jacks can be used to raise avtoplatform, scenes for the opening and closing hatches or massive transoms.