Cubic Screw Jacks MJ/BJ Series
A Cubic Screw Jack is used wherever controlled lifting, lowering and slewing is required. They can be installed singly, in pairs or as part of a multiple jack system.
Key features:
- Lifting force from 2.5 kN to 500 kN
- Linear speeds up to 1.5 m/min
- 11 sizes in two gear ratios for normal and slow linear speeds using trapezoidal spindles
- Ball screw options for higher linear speeds
- Can be mounted in any attitude
- Generally maintenance free
- Gear casings aluminium or grey cast iron in a cubic form
- Food quality options and many specials available
In Version AS a travel limiter is fitted to prevent overtravel of the spindle. In Version VS spindle rotation prevention is included. In Version AS-VS both overtravel and spindle rotation prevention is provided.

 
       
    Version G
Translating (Basic)
In Version G the spindle provides the linear motion. In this design the spindle moves axially through the jack nut. Rotation of the spindle must be prevented; usually by fixing the end of the spindle to the item being moved.
Accessories
Accessories available include spindle ends, safety nuts, bellows, limit switches, trunnion adaptors, handwheels, mounting feet, cardan shafts, support bearings, bevel gearboxes, couplings to motors and motor adaptor flanges.
Materials
Available in cast iron and aluminium bodies.
 
    Version LM
Rotating (Travelling nut)
In Version LM the spindle is axially fixed and linear motion is transmitted to the running nut by rotation of the spindle. The nut must be secured against rotation by fixing to the item or mechanism being moved.
Accessories
Accessories available include spindle ends, safety nuts, bellows, limit switches, trunnion adaptors, handwheels, mounting feet, cardan shafts, support bearings, bevel gearboxes, couplings to motors and motor adaptor flanges.
Materials
Available in cast iron and aluminium bodies.
| Type | Lifting Force kN | Spindle Size | Ratio - Normal | Ratio - Stroke/rev | Ratio - Slow | Ratio - Stroke/rev | Gear Housing | 
|---|---|---|---|---|---|---|---|
| MJ0 | 2.5 | Tr 16×4 | 4:1 | 1 mm | 20:1 | 0.20 mm | Aluminium | 
| MJ1 | 5.0 | Tr 18×4 | 4:1 | 1 mm | 16:1 | 0.25 mm | Aluminium | 
| MJ2 | 10.0 | Tr 20×4 | 4:1 | 1 mm | 16:1 | 0.25 mm | Aluminium | 
| MJ3 | 25.0 | Tr 30×6 | 6:1 | 1 mm | 24:1 | 0.25 mm | Aluminium | 
| MJ4 | 50.0 | Tr 40×7 | 7:1 | 1 mm | 28:1 | 0.25 mm | GGG50 | 
| MJ5 | 100.0 | Tr 55×9 | 9:1 | 1 mm | 36:1 | 0.25 mm | GGG50 | 
| BJ1 | 150.0 | Tr 60×9 | 9:1 | 1 mm | 36:1 | 0.25 mm | GGG50 | 
| BJ2 | 200.0 | Tr 70×10 | 10:1 | 1 mm | 40:1 | 0.25 mm | GGG50 | 
| BJ3 | 250.0 | Tr 80×10 | 10:1 | 1 mm | 40:1 | 0.25 mm | GGG50 | 
| BJ4 | 350.0 | Tr 100×10 | 10:1 | 1 mm | 40:1 | 0.25 mm | GGG50 | 
| BJ5 | 500.0 | Tr 120×14 | 14:1 | 1 mm | 56:1 | 0.25 mm | GGG50 | 
Downloads
 
                    | Name | Files | 
|---|---|
| Full GROB Catalogue | |
| Lifting Solutions Catalogue | |
| Drive Lines Product Brochure | |
| Application Questionnaire | |
| Lubrication Information | |
| Frequently Asked Questions | 
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