ACME screw jacks for medium to high force linear motion

Screw jacks or screw jacks transform a rotary input into linear movement in a vertical or horizontal plane. Both push and pull loads are acceptable in any mounting orientation. Inputs are generally from electric motors connected by couplings or directly by flange.

Screw jacks deliver medium to high forces (5 to 1,000 kN) in linear motion for strokes that can be chosen between 100 mm and 6 m. Linear speeds up to 300 mm/s and duty cycles up to 40% are possible with ACME screw jacks. Higher speeds and duty cycles to 100% can be achieved with ball screw jacks. A comprehensive range of options includes safety nuts, motorised models and stroke limit switches.

Multiple screw jacks can be combined into a lifting system. Powered by a geared motor, the jacks are connected often in an 'H' configuration by couplings and bevel gears.

These ACME thread screw jacks are designed for general duties where force (0.5 to 100 tonnes) and stroke (up to 6 m) are the key criteria. Where higher speeds and efficiency are needed see also our Ball Screw Jacks.

• Strong UK technical support and experience
• Modern metric-based designs, SJ is cube shaped, unlike traditional products such as those from Power Jacks and Duff Norton
• High performance with maximum input speeds of 3,000 r/min, duty cycles of 40% without derating
• Complete lifting systems with geared motors and couplings available

TYPE SJ FOR GENERAL PURPOSE USE, 5 TO 1000 KN (100 TONNES)

SJ ACME screw jacks suit general duties with loads from 0.5 to 100 tonnes. Fourteen models suit lifting loads from 5 to 1,000 kN and linear speeds can be up to 85.7 mm/s. Maximum duty cycles are up to 30% based on a 10-minute period. Strokes up to 6m are possible subject to load guidance and critical speeds.

SJ screw jacks have a monobloc housing in cast iron (except SJ05 & SJ10 in aluminium). The square shape is easy to mount. ACME screws are constructed in C43 steel with 1 or 2 starts. SJ screw jacks have 4 ratios per size, also a choice of 1 or 2 start ACME screws.

SJ screw jacks are available in travelling screw and travelling nut designs. They have equal dynamic performance and the choice depends on your mounting/installation.

TYPE MA WITH HIGH EFFICIENCY 5 TO 350 KN (35 TONNES)

Type MA ACME screw jacks are part of our product range and feature upgraded construction for increased loads and duties. Eight models suit lifting loads from 5 to 350 kN and linear speeds up to 300mm/s are possible. Maximum duty cycles are up to 40% based on a 10-minute cycle, strokes up to 6m are possible subject to load guidance and critical speeds.

Travelling screw and travelling nut designs are available with equal performance. Each model has 4 possible gear ratios and in addition the ACME screws can be 1,2,3 or 4 start resulting in a precise match to the required performance.

Standard options include electric motors, safety nuts, protective tubes, bellows, trunnion mounting, anti-turn, microswitches, wear detection and adjustable backlash.