Product Definition & Working Principle

Screw jack (also known as worm gear screw lifter) is a basic lifting and adjusting device that converts rotary motion into linear motion. Its core assembly consists of a worm-worm gear set and a lifting nut. It can be driven by an electric motor or handwheel. When the worm rotates, the worm gear pair reduces speed and amplifies torque. The worm gear then drives the nut to rotate, pushing the spindle to perform linear movement (or the spindle stays fixed while the nut travels along it), thereby realizing lifting, pushing, horizontal shifting, tilting and other movements of loads.

🛠️ Core Structure & Main Types

Drive Power Options

Electric drive (motor) or manual drive (handwheel) are both available.

Transmission Mechanisms

1. Worm-worm gear transmission (mainstream): strong self-locking capacity, low noise, easy installation.
2. Gear transmission (optional): high efficiency, fast speed, requires matched brake.

Screw Drive Pairs

• Trapezoidal screw: Sliding friction, self-locking to prevent load slipping, low cost, efficiency ranges 25%–40%.
• Ball screw: Rolling friction, ultra-high efficiency (92%–98%), high positioning accuracy, no self-locking function, higher cost.

Two Spindle Motion Configurations

1. Traveling spindle type: Nut fixed, spindle extends/retracts, applicable for long stroke.
2. Traveling nut type: Spindle fixed, nut moves up and down, short overall length, superior rigidity.

👍 Performance Advantages

1. Compact structure: Small footprint, lightweight, flexible installation, suitable for space-limited environments.
2. Heavy load capacity: Standard load range 2.5–120 tons; customized heavy-duty models support up to 500 tons to meet industrial heavy-load demands.
3. Precise positioning: Positioning accuracy up to ±0.1 mm, perfect for precision adjustment scenarios.
4. Safe self-locking: Trapezoidal screw retains load position automatically upon power cut-off, avoiding load falling and boosting operational safety.
5. Multi-unit synchronous operation: Supports synchronized running of 2/4/8 units, delivering stable, jitter-free lifting platform movement.

⚠️ Notes for Use

• Trapezoidal screws feature low efficiency and are not suitable for long-duration high-speed continuous operation; users must comply with rated duty cycles.
• Ball screws have no self-locking function. Brakes or brake motors must be equipped to stop load sliding.

📌 Typical Application Scenarios

• Industrial automation: Lifting platforms on production lines, tooling positioning, machine tool Z-axis, synchronous lifting platforms.
• Metallurgy & mining: Furnace door lifting, gate opening/closing, heavy load jacking, mining equipment adjustment.
• Construction & stage: Stage lifts, lighting stand regulators, construction lifting equipment.
• Medical & food industry: Hospital bed height adjustment, packaging machine height tuning, food processing equipment positioning.

🏭 Manufacturer Strength

As a direct manufacturer, Dezhou Darui Machinery Co., Ltd. supplies full-series SWL/SJB screw jacks and non-standard customization services. We boast three core strengths: 500-ton heavy load capacity, safety nut monitoring system and ultra-high precision. Our products have been supplied to enterprises including CATL and BYD, delivering reliable quality and customized one-stop solutions.