Metric Series Worm Gear Screw Jacks are widely used in industrial lifting, positioning, and load-holding applications where precision, reliability, and compact design are critical. These screw jacks are engineered to handle heavy loads at controlled speeds while offering excellent mechanical advantage. Understanding their specifications and load capacity is essential for selecting the right model for your application and ensuring long-term performance and safety.

This detailed guide explains the technical specifications, load ratings, working principles, materials, efficiency, and application suitability of Metric Series Worm Gear Screw Jacks in a clear and practical way.

What Are Metric Series Worm Gear Screw Jacks

Metric Series Worm Gear Screw Jacks are mechanical lifting devices that convert rotational motion into linear motion using a worm gear mechanism and a metric-threaded lifting screw. They are designed according to metric standards, making them compatible with global machinery designs and industrial systems.

These jacks are commonly used where:

  • Precise vertical or horizontal movement is required

  • Loads must be held securely without slipping

  • Synchronised lifting systems are needed

  • Harsh industrial environments demand rugged construction

Working Principle of Metric Series Worm Gear Screw Jacks

The working mechanism is based on worm gear reduction:

  1. Input rotation is applied through a hand wheel, electric motor, or gearbox.

  2. The worm shaft rotates the worm wheel.

  3. The worm wheel drives the lifting screw.

  4. The screw moves linearly upward or downward depending on rotation direction.

Due to the high gear reduction, Metric Series Worm Gear Screw Jacks provide:

  • High load-lifting capability

  • Smooth and controlled movement

  • Self-locking characteristics in most ratios

Key Specifications of Metric Series Worm Gear Screw Jacks

Understanding specifications is critical for correct selection. Below are the most important technical parameters.

Load Capacity Range

Metric Series Worm Gear Screw Jacks are available in a wide range of load capacities, typically:

  • 500 kg to 50 tons (and higher in custom designs)

  • Suitable for light-duty, medium-duty, and heavy-duty industrial applications

Load capacity depends on:

  • Screw diameter

  • Thread type

  • Gear ratio

  • Material strength

  • Duty cycle

Lifting Screw Types

Metric Series Worm Gear Screw Jacks are generally available with:

  1. Translating Screw Type

    • Screw moves linearly

    • Nut is fixed inside the gearbox

    • Ideal where space above the jack is available

  2. Rotating Screw Type

    • Screw rotates but does not travel

    • Nut moves linearly

    • Suitable for limited headroom applications

Screw Thread Specifications

  • Metric trapezoidal threads (ISO standard)

  • Optimized for strength and wear resistance

  • Designed for long service life under heavy loads

Thread pitch selection impacts:

  • Lifting speed

  • Load handling efficiency

  • Precision control

Gear Ratios

Common gear ratios include:

  • 5:1

  • 10:1

  • 20:1

  • 30:1 and above

Higher gear ratios provide:

  • Greater load capacity

  • Higher self-locking ability

  • Lower lifting speed

Materials of Construction

High-quality Metric Series Worm Gear Screw Jacks are manufactured using:

  • Housing: Cast iron or ductile iron for vibration damping and durability

  • Worm Gear: Phosphor bronze for smooth meshing and wear resistance

  • Worm Shaft: Alloy steel, case hardened or ground

  • Lifting Screw: High-strength alloy steel or carbon steel

Material quality directly impacts load rating and service life.

Load Capacity Explained in Detail

Load capacity refers to the maximum axial load the screw jack can lift or hold safely under defined conditions.

Static Load Capacity

  • Maximum load the jack can hold when not moving

  • Important for applications involving load holding for long durations

Dynamic Load Capacity

  • Maximum load the jack can lift or lower continuously

  • Depends on duty cycle and operating speed

Side Load Considerations

Metric Series Worm Gear Screw Jacks are primarily designed for axial loads. Excessive side loading can:

  • Reduce lifespan

  • Increase wear on threads

  • Cause misalignment

Proper guides or external supports are recommended for side-load conditions.

Efficiency and Self-Locking Characteristics

One major advantage of Metric Series Worm Gear Screw Jacks is self-locking behavior.

  • Most worm gear designs prevent back-driving

  • Load remains in position when input power is removed

  • Enhances operational safety

Efficiency typically ranges between:

  • 30% to 50%, depending on gear ratio and lubrication

Lower efficiency is a trade-off for higher load safety and holding capability.

Speed and Stroke Length Options

Lifting Speed

  • Depends on gear ratio and screw pitch

  • Designed for controlled, precise movement rather than high speed

Stroke Length

  • Standard strokes: 100 mm to 1000 mm

  • Custom strokes available based on application needs

Mounting and Orientation Flexibility

Metric Series Worm Gear Screw Jacks can be mounted in:

  • Upright position

  • Inverted position

  • Horizontal configuration

Multiple mounting options allow easy integration into:

  • Lifting platforms

  • Industrial presses

  • Conveyor systems

Typical Applications of Metric Series Worm Gear Screw Jacks

Because of their versatility, Metric Series Worm Gear Screw Jacks are used in:

  • Steel plants and rolling mills

  • Automotive manufacturing lines

  • Material handling equipment

  • Lifting platforms and scissor lifts

  • Industrial automation systems

  • Packaging and printing machinery

  • Synchronized multi-jack lifting systems

Advantages of Metric Series Worm Gear Screw Jacks

  • High load-bearing capability

  • Precise positioning control

  • Long service life

  • Compact and rugged design

  • Metric standard compatibility

  • Low maintenance requirement

Maintenance and Lubrication Guidelines

For long-term reliability:

  • Use recommended gear oil or grease

  • Maintain proper lubrication intervals

  • Check screw threads for wear

  • Avoid overload conditions

Regular maintenance ensures consistent load capacity and smooth operation.

How to Select the Right Metric Series Worm Gear Screw Jack

When selecting a screw jack, consider:

  • Required load capacity (static and dynamic)

  • Stroke length

  • Operating speed

  • Duty cycle

  • Mounting orientation

  • Environmental conditions

Correct selection prevents premature failure and ensures optimal performance.

Conclusion

Metric Series Worm Gear Screw Jacks are a reliable and efficient solution for industrial lifting and positioning applications where strength, precision, and safety are essential. Understanding their specifications and load capacity allows engineers and buyers to make informed decisions and select the most suitable model for their operational needs.

With proper selection, installation, and maintenance, these screw jacks deliver consistent performance across a wide range of industrial environments.