Double-Legged Gantry Cranes

Double-legged gantry cranes are ideal for heavy-duty outdoor and indoor lifting, offering superior stability, mobility, and load capacity. They are widely used in:
✅ Ports & shipbuilding
✅ Steel & power plants
✅ Construction & logistics

 

Advantages

✔ High Stability – Four-point support reduces tipping risks.
✔ Heavy-Duty Capacity – Handles 5–500+ tons, ideal for shipyards and steel plants.
✔ Mobility Options – Can be rail-guided or wheel-mounted for flexibility.
✔ No Building Modifications – Freestanding design eliminates need for runway beams.
✔ Outdoor Suitability – Wind-resistant and corrosion-protected for harsh environments.

 

Single vs. Double-Legged Gantry Cranes

Feature	Double-Legged	Single-Legged (Semi-Gantry)
Stability	High (4-point support)	Moderate (2-point support)
Max Capacity	Up to 500+ tons	Typically ≤50 tons
Mobility	Rail or rubber-tired	Usually fixed or light mobile
Applications	Heavy industry, shipyards	Workshops, small warehouses

 

Core Components PLC, Engine, Bearing, Gearbox, Motor, Pressure vessel, Gear, Pump

Place of Origin Henan, China

Warranty 1 Year

Weight (KG) 30000 kg

Application Precast yard, construction site, warehouse, etc.

Product name 40 ton straddle carrier rubber tired single girder gantry cranes

Crane Type A Type, Single Girder, Double Girder Straddle Carrier

Lifting mechanism Customer Requirements

Control Method Cabin Control+Remote Control

Lifting Capacity 5~1200 Ton

Multiple Steering Modes Go straight, transverse traveling, carousel steering, etc.

Install On-site and online

Motor Famous brand

Work Duty A3~A5

 

A Double-Legged Gantry Crane is a freestanding lifting system with two supporting legs on each side, enabling mobility and heavy-load handling without requiring an overhead runway structure. Below is a detailed breakdown of its key components:

 

1. Main Structural Components

A. Gantry Frame

Double Legs (Two on Each Side) – Provide stability and distribute load weight.

Top Beam (Bridge Girder) – Connects the legs and supports the hoist/trolley.

Cross Beams & Bracing – Reinforce structural integrity to prevent swaying.

B. End Trucks (Travel Units)

Wheels/Tracks – Allow the crane to move along rails or ground surfaces.

Drive Motors – Power the gantry's longitudinal movement (rail-mounted or rubber-tired).

Buffers/Bumpers – Absorb shocks during travel.

2. Lifting Mechanism

A. Hoist Unit

Electric Wire Rope Hoist – Common for heavy loads (e.g., 10–500 tons).

Chain Hoist – Used for lighter capacities or hazardous environments.

Drum & Rope/Chain – Lifting medium with high tensile strength.

B. Trolley Assembly

Trolley Frame – Moves horizontally along the top beam.

Trolley Drive Motor – Powers transverse movement (across the girder).

Guide Rollers – Keep the trolley aligned.

3. Support & Mobility Systems

A. Runway/Rail System

Fixed Rails – For precise movement in industrial settings.

Rubber-Tired Wheels – For mobility on flat surfaces (no rails needed).

B. Outriggers/Stabilizers (Optional)

Extendable supports for additional stability when lifting heavy loads.

4. Power & Control Systems

Cabin Control – Operator cabin mounted on the gantry.

Pendant Control – Handheld remote (wired/wireless).

Festoon/Cable Reel – Manages power and signal cables.

Variable Frequency Drive (VFD) – Ensures smooth acceleration/deceleration.

5. Safety Components

Limit Switches – Prevent over-travel of hoist/trolley.

Overload Protector – Blocks operation if load exceeds capacity.

Anti-Collision System – For multiple gantry cranes in the same area.

Emergency Stop (E-Stop) – Instantly cuts power.

Windproof Anchors – Secure the crane in outdoor applications.

6. Optional Features

Cabin with AC/Heating – For operator comfort.

Automated Positioning (GPS/Laser Guide) – For precision in shipyards.

Weighing System – Integrated load measurement.

LED Lighting – For low-light conditions.

Sketch

 

Enhanced Stability & Safety

Four-point support system (two legs per side) provides superior balance

Reduced sway and oscillation during heavy load movements

Lower risk of tipping compared to single-leg designs

Heavy Load Capacity

Typical capacity range: 5-500+ tons

Robust construction handles extreme weights in industrial settings

Ideal for massive components like ship sections or power plant equipment

Flexible Mobility Options

Rail-mounted versions for precise, guided movement

Rubber-tired models for versatile positioning

Some models feature track-changing capability for multi-line operations

Freestanding Operation

Doesn't require building support structures

Can be installed without modifying existing facilities

Ideal for outdoor applications where overhead cranes aren't feasible

Adaptable to Harsh Environments

Corrosion-resistant coatings for marine/coastal use

Wind-resistant designs with optional anchoring

Suitable for extreme temperatures (-20°C to +50°C)

Precision Handling

Optional anti-sway systems for delicate positioning

Fine-control options for sensitive loads

Can integrate with automated positioning systems

 

1. Ports & Shipbuilding

Container loading/unloading

Ship section assembly

Dry dock maintenance operations

Offshore platform component handling

2. Heavy Industry

Steel mill coil and slab transfer

Foundry ladle handling

Heavy machinery installation

Transformer positioning in power plants

3. Construction & Infrastructure

Precast concrete beam installation

Bridge segment placement

Tunnel construction material handling

Dam construction equipment movement

4. Energy Sector

Wind turbine assembly

Nuclear plant component installation

Hydroelectric generator maintenance

Oil refinery equipment handling

5. Specialized Manufacturing

Aerospace component movement

Railway rolling stock assembly

Mining equipment maintenance

Large-scale fabrication workshops

 

 

1. Design stage: Determine the parameters of the crane, such as rated load, span and lifting height, according to the customer's needs and working environment. Carry out detailed structural design, including main beam, end beam, crane, lifting mechanism, etc., to ensure that the design meets safety standards and usage requirements. Select appropriate materials according to the design, usually high-strength steel to ensure the stability and durability of the structure.

2. Manufacturing stage: Prepare the required raw materials and parts according to the design drawings. Cut, bend and shape the steel to prepare structural components such as main beams and end beams. Weld the various components and assemble them into an overall structure. This step requires guaranteed welding quality to ensure strength and stability.

3. Machining: Machining key components such as motors, gears, bearings, etc. to ensure that their size and accuracy meet the requirements. Anti-corrosion treatment of components, such as painting and galvanizing, increases the durability and aesthetics of the equipment.

4. Electrical system installation: Install electrical components such as motors, controllers, switches, sensors and alarm systems. Connect and wire cables to ensure the normal operation of the electrical system.

5. Assembly phase: Assemble all components and systems as a whole, connect the lifting mechanism, trolley running mechanism and control system. Perform a comprehensive inspection of the assembled crane to ensure that all components and systems are working properly, and perform preliminary debugging.

6. Testing phase: Perform static load test on the crane to check the structural strength and stability. Perform dynamic test on the crane, including tests on lifting, moving, braking and other functions, to ensure that its performance meets the design requirements. Check the functions of safety devices, such as limit switches, overload protection, etc., to ensure the safety of the equipment during operation.

7. Quality control: Perform quality control on each link in the production process to ensure compliance with industry standards and customer requirements. Record various data and inspection results in the production process for subsequent traceability and analysis.

8. Delivery and installation: Pack and prepare the completed crane for transportation to ensure that it is not damaged during transportation. Deliver the crane to the customer's site for installation, and perform on-site debugging and acceptance. Provide operation training to customers to ensure that they are proficient in the use and maintenance of the crane.

Workshop view:

The company has installed an intelligent equipment management platform, and has installed 310 sets (sets) of handling and welding robots. After the completion of the plan, there will be more than 500 sets (sets), and the equipment networking rate will reach 95%. 32 welding lines have been put into use, 50 are planned to be installed, and the automation rate of the entire product line has reached 85%.