20 Ton Double Girder Goliath Gantry Crane

1. Product Overview
The 20-ton Double Girder Goliath Gantry Crane is a heavy-duty lifting solution designed for outdoor and indoor applications where an overhead crane structure is not feasible. It features a double-girder design, which provides superior strength and stability, making it ideal for handling heavy loads in ports, shipyards, construction sites, railway yards, and industrial warehouses.

2. Key Features
High Lifting Capacity – Capable of handling up to 20 tons of load with high efficiency.
Double Girder Structure – Ensures excellent load distribution, reducing stress on the crane.
Customizable Span & Height – Designed to fit various work environments.
Smooth & Precise Operation – Equipped with variable frequency drive (VFD) for speed control.
Reliable Safety Mechanisms – Includes overload protection, limit switches, emergency stop systems, and anti-collision devices.
Weatherproof Design – Suitable for outdoor use with corrosion-resistant materials and IP-rated electrical components.
Multiple Control Options – Available with wireless remote control, cabin control, or pendant control.

Core Components：Engine, Bearing, Gearbox, Motor, Gear

Place of Origin：Henan, China

Warranty：2 years

Weight (KG)：50000 kg

Video outgoing-inspection：Provided

Machinery Test Report：Provided

Application：Outdoor

Keywords：Gantry Crane

Rated Loading Capacity：50Ton

Cross travelling speed：44.6m/min

Long travelling speed：47.1m/min

Control way：cabin

Power supply：Cable reel

Steel track：QU80

Power：3-phase AC 50HZ 380V

1.Main beam

1)Overview
The main beam is the primary load-bearing structure of a 20-ton Double Girder Goliath Gantry Crane. It consists of two parallel girders that span across the crane's width and provide support for the trolley and hoisting mechanism. The design ensures high strength, stability, and load distribution, making it suitable for lifting heavy loads in industrial environments.

2)Structural Design & Construction
Double Girder Configuration – Provides better load distribution and higher lifting capacity compared to single girder designs.
High-Quality Steel Material – Typically made of Q235B or Q345B steel, ensuring durability and strength.
Box Girder or Truss Girder Design –
Box girder: Fully enclosed structure, offering higher rigidity and load-bearing capacity.
Truss girder: Lightweight, wind-resistant, suitable for large spans.
Welded & Machined for Precision – Main beams are welded using submerged arc welding (SAW) and machined to high accuracy to ensure smooth trolley movement.

2.Lifting System

1)Hoisting Mechanism
The hoisting mechanism is responsible for lifting and lowering loads. It includes:
Electric Wire Rope Hoist: The primary lifting device, typically mounted on a trolley that moves along the girders.
Wire Rope & Hook: The wire rope is wound around a drum and connected to a hook to lift the load.
Lifting Motor: Provides the power needed to lift and lower loads.
Gearbox & Brake System: Controls speed and ensures safety by preventing accidental load drops.
2)Trolley System
The trolley moves horizontally along the double girders, allowing for precise positioning of the load. It consists of:
Trolley Frame: Supports the hoist and other components.
Trolley Wheels: Run on rails mounted on the girders.
Trolley Motor & Drive System: Powers the horizontal movement.
3)Electrical & Control System
The electrical system ensures smooth operation and includes:
Control Panel: Houses the electrical components, including contactors and relays.
Limit Switches: Prevents over-travel of the hoist and trolley.
Pendant Control / Remote Control: Allows the operator to control lifting, lowering, and trolley movement.
Variable Frequency Drive (VFD) (Optional): Provides smooth speed control for precise operation.
4)Safety Features
Overload Protection: Prevents lifting beyond the rated capacity.
Emergency Stop System: Stops operations in case of an emergency.
Anti-collision Sensors: Prevents collisions with other objects.

3.End carriage

1)Structure & Design
Main Beam Connection: The end carriages are attached to the double girders, providing stability and load distribution.
Robust Steel Frame: Made from high-strength steel to withstand heavy loads and operational stresses.
Box-Type or Welded Structure: Ensures durability and rigidity.
2)Traveling Mechanism
The end carriage is equipped with a traveling system that moves the crane along the ground rails:
Wheel Assemblies: Large-diameter, high-strength steel wheels designed for smooth movement.
Drive Units (Motor & Gearbox):
Powered by electric motors (usually with a VFD for smooth acceleration and deceleration).
Gearboxes transmit power efficiently to the wheels.
Rail Clamps & Buffers (Optional): Prevents unwanted movement during strong winds.
Braking System:
Electromagnetic or Hydraulic Brakes to ensure safe stopping.
Emergency Stop System for additional safety.

4.Crane travelling mechanism

Traveling Drive System
The crane moves along the ground rails using motorized drive units, consisting of:
1)Driving Motors:
Typically three-phase asynchronous motors.
May use Variable Frequency Drive (VFD) for smooth acceleration, speed control, and energy efficiency.
2)Gearbox & Transmission System:
The motor drives a hardened gearbox that reduces speed and increases torque.
Uses helical or planetary gears for efficient power transmission.
3)Wheel System:
Driven Wheels: Powered by the motors and gearboxes.
Idle Wheels: Free-moving support wheels to balance the load.
Material: Forged steel with heat treatment for durability.
Flanged design to keep the wheels securely on the rail track.
4)Braking System:
Electromagnetic or hydraulic brakes for controlled stopping.
Emergency brakes for additional safety.

5.Trolley travelling mechanism

1)Structural Components
Trolley Frame:
A heavy-duty steel frame that houses the hoisting mechanism.
Designed to move smoothly along the top flange of the double girders.
Trolley Wheels:
Four or more wheels, depending on the design.
Made of forged steel with heat treatment for durability.
Flanged wheels to prevent derailment.
2)Safety & Control Features
Limit Switches: Prevent over-travel beyond the designated range.
Braking System:
Electromagnetic or hydraulic brakes ensure controlled stopping.
Emergency brakes for additional safety.
Anti-Slip & Anti-Skew Systems: Ensures smooth movement and prevents misalignment.
Overload Protection: Prevents excessive loads from damaging the system.

6.Crane wheel

1)Types of Crane Wheels
A 20-ton double girder goliath gantry crane typically uses the following types of wheels:
Driven Wheels: Connected to the motor and gearbox, providing movement.
Idle Wheels (Non-driven): Support the crane's weight and roll freely.
Flanged Wheels: Have a raised edge (flange) to keep the crane aligned on the rails.
Double-Flanged Wheels (Optional): Provide extra stability for high-precision applications.
2)Material & Manufacturing Process
Material:
High-strength forged steel (e.g., 42CrMo, 65Mn, or ZG430-640).
Heat-treated for high wear resistance and durability.
Hardness:
Surface hardness: HRC 40–50 (for wear resistance).
Core hardness: Lower to maintain toughness.
Manufacturing Process:
Forging → Machining → Heat Treatment → Final Grinding & Testing.

7.Crane Hook

1)Types of Crane Hooks
The choice of hook depends on the lifting application:
Single Hook:
Used for general lifting applications.
Simple design with a rotating swivel to prevent twisting.
Double Hook:
Used for wide or heavy loads to ensure even weight distribution.
Provides better stability than a single hook.
Forged Hook vs. Laminated Hook:
Forged Hook: Made from a single piece of high-strength steel, stronger and more durable.
Laminated Hook: Made from multiple steel plates, used for extra safety (reduces risk of sudden failure).
2)Material & Manufacturing
Material:
High-strength carbon steel or alloy steel (e.g., 20MnSi, 34CrMo4).
Designed to handle high loads and resist deformation.
Heat Treatment:
Increases hardness and durability.
Reduces wear and extends service life.
Safety Factor:
Typically 4:1 or 5:1 to ensure safe lifting operations.

8.Motor

Features & Specifications
1)Power Supply:
Three-phase power supply is the standard, as it provides a more balanced, efficient, and reliable power source for heavy-duty applications.
Frequency: Typically 50 Hz or 60 Hz, depending on local electrical standards.
2)Enclosure & Protection:
IP54 or IP55 protection rating to protect against dust and water.
Class F or H insulation to handle higher operating temperatures.
Cooling system: Most motors are equipped with forced ventilation or cooling fans to prevent overheating during extended operations.
3)Starting System:
Star-Delta (Wye-Delta) or Autotransformer starters for smooth motor startup and to reduce inrush current.
Soft Starter or VFD: Often used for trolley and traveling motors to gradually ramp up the speed, improving the longevity of the motor and reducing mechanical stress.

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9.Sound and light alarm system & limit switch

1)Sound and Light Alarm System
The sound and light alarm system provides visual and audible alerts to warn of specific crane operating conditions such as approaching overload, limit range, or emergency situations.
2)Limit Switches
Limit switches are safety devices that prevent the crane from exceeding its designed operational range. These switches are critical for ensuring safe operation and avoiding mechanical damage or safety hazards.

10.Safety Devices

1)Overload Protection System
Purpose: Prevents the crane from lifting loads beyond its rated capacity, which could lead to structural damage or catastrophic failure.
2)Limit Switches
Purpose: Ensures the crane does not exceed its designed operational limits, preventing mechanical damage or dangerous operation.
3)Emergency Stop System
Purpose: Provides a quick shutdown mechanism for all crane operations in case of an emergency.
4)Anti-Collision System
Purpose: Prevents the crane from colliding with nearby objects, other cranes, or structures, improving safety in environments with multiple cranes.
5)Sound and Light Alarm System
Purpose: Warns nearby personnel of crane movements and abnormal conditions.
6)Anti-Sway System
Purpose: Reduces load swing during crane movements, improving safety, precision, and load control.
7)Brake Systems
Purpose: Provide secure stopping and hold capabilities for the crane, preventing movement when it's not desired.

11.Control Mode

1)Pendant Control (Wired Control)
Description:
A pendant control is a handheld device connected to the crane via a flexible cable. It allows the operator to control crane movements from a distance while staying on the ground or within the crane's vicinity.
2)Radio Remote Control (Wireless Control)
Description:
A radio remote control allows the crane to be operated wirelessly from a distance using a hand-held device with buttons, joysticks, or touchscreens.
3)Cabin Control (Operator Cabin)
Description:
In cabin control, the operator is seated in a fully enclosed cabin on the crane, providing a clear view of the load, lifting area, and crane components.
4)Automatic / Semi-Automatic Control
Description:
Automatic control refers to systems where the crane is programmed to perform specific tasks automatically, based on pre-set parameters or programmed commands.
Semi-automatic control allows the operator to set certain parameters (such as speed or travel distance) while still having manual control over certain movements.

12.Sketch

Main technical

1. High Load Capacity
Heavy Lifting Capacity: With a 20-ton capacity, the crane can safely handle very heavy loads, making it ideal for industrial applications such as lifting large equipment, precast concrete, or shipbuilding materials.
Double Girder Design: The double girder configuration offers superior strength and stability compared to single girder cranes, allowing it to lift and support heavier loads with greater safety.
2. Flexibility and Versatility
Multiple Control Options: A 20-ton double girder goliath gantry crane can be equipped with various control systems (e.g., pendant control, radio remote control, cabin control), providing flexibility to suit different operational needs.
Wide Range of Applications: These cranes can be used in a variety of settings, including shipyards, ports, construction sites, and manufacturing plants, making them versatile across different industries.
Adjustable Speeds and Movements: Depending on the design, these cranes offer precise control over lifting, lowering, and horizontal movement, ensuring that loads are moved with accuracy and minimal risk.
3. Enhanced Safety Features
Overload Protection: The crane is equipped with overload protection systems to ensure that the crane does not exceed its rated capacity, preventing accidents and damage.
Limit Switches: Installed at various points along the crane's travel path and hoist, these switches prevent the crane from moving beyond its designated range, protecting the crane and the surrounding environment.
Emergency Stop and Safety Alarms: The crane is fitted with emergency stop systems and sound and light alarms to alert operators and nearby workers of hazardous conditions.
Wind Speed Monitoring: For outdoor cranes, a wind speed monitoring system can automatically stop crane operations if wind speeds exceed safe operating thresholds, reducing the risk of accidents during harsh weather.
4. Improved Efficiency and Productivity
High-Speed Operation: These cranes are capable of moving quickly across large areas, reducing the time spent transporting heavy loads and increasing operational efficiency.
Reduced Manual Labor: With automated features and precise control, operators can handle heavier loads with less effort, reducing the need for manual labor and improving productivity.
Continuous Operation: The robust design of the double girder structure allows for extended periods of continuous operation without compromising performance or safety.
5. Durability and Longevity
Robust Construction: The double girder design makes the crane more stable and capable of withstanding heavy-duty usage in harsh outdoor environments, such as high winds, extreme temperatures, and corrosive elements.
Low Maintenance: Due to their durable components and robust design, these cranes require minimal maintenance, helping to reduce downtime and maintenance costs.
Weather-Resistant: Goliath gantry cranes are specifically designed to work in outdoor environments, meaning they are built to endure various weather conditions without affecting performance.
6. Increased Reach and Accessibility
Large Span: The crane can cover a large area, making it ideal for tasks that require wide horizontal movement, such as loading/unloading materials from ships or moving equipment across construction sites.
Height Advantage: The double girder design provides greater lifting height, making it suitable for lifting heavy loads from substantial heights or between structures with significant vertical clearance.

1. Shipyards and Marine Industry
Shipbuilding and Ship Repair: Goliath gantry cranes are commonly used in shipyards for lifting and transporting heavy ship parts, such as large hull sections, engines, and other components. The crane's large span and lifting capacity allow it to move these heavy and oversized components across the yard.
Load and Unload Ships: These cranes are also used for loading and unloading cargo from ships, such as steel plates, equipment, and other heavy materials. The crane can easily move cargo from the dock to land and vice versa.
2. Construction Industry
Heavy Lifting: A 20-ton double girder goliath gantry crane is ideal for handling large construction materials like concrete beams, steel structures, and prefabricated parts. The crane's ability to handle heavy loads makes it crucial for high-rise construction, bridge building, and large-scale infrastructure projects.
Transporting Materials on Construction Sites: The crane can be used to move materials around construction sites, such as large equipment, steel beams, and precast concrete panels, improving efficiency and reducing manual labor.
3. Industrial Manufacturing
Heavy Equipment Handling: In manufacturing plants, particularly those involved in steel production, automotive manufacturing, or heavy machinery, the crane can be used to lift and move heavy machines, motors, and equipment during assembly, maintenance, and installation processes.
Steel Mills: Goliath gantry cranes are frequently used in steel mills to handle heavy steel coils, billets, and large rolls of steel. The crane's design allows it to operate in harsh environments with high temperatures and heavy workloads.
4. Power Plants
Maintenance and Installation of Equipment: In power plants, the 20-ton gantry crane is used to move generators, turbines, transformers, and other heavy equipment during installation or maintenance. This is critical for power generation plants, especially nuclear, hydroelectric, and thermal power stations, where heavy machinery needs to be moved with precision.
Wind Turbine Assembly: Some power plants, particularly those involved in wind energy, use goliath gantry cranes for assembling wind turbines or moving heavy components like rotor blades and generaors.
5. Ports and Shipping Terminals
Container Handling: Goliath gantry cranes are extensively used in ports for loading and unloading containers from ships. Their ability to handle heavy loads over a wide span allows them to efficiently load and unload cargo, reducing turnaround times for ships in busy port environments.
Bulk Material Handling: These cranes are also used to handle bulk materials, such as coal, grain, or sand. They can load bulk material onto trucks, barges, or ships, and unload it from various transport modes at the terminal.

1. Design & Engineering
Requirement Analysis: Determine specifications, including span, height, duty cycle, and environmental conditions.
CAD Drawings & Load Calculations: Engineers design the crane structure, ensuring compliance with international safety standards like FEM, CMAA, or ISO.
Selection of Key Components: Includes double girders, end carriages, trolley mechanism, hoisting system, and electrical controls.
2. Material Procurement
Structural Steel: High-strength steel plates and beams for girders, legs, and supporting structures.
Hoisting Mechanism: Motor, gearbox, wire rope, and drum are sourced.
Electrical & Control Components: Inverters, limit switches, PLC, and control panels.
3. Fabrication of Structural Components
Double Girder Manufacturing
Cutting: Steel plates are cut into precise shapes.
Welding: Girders are welded using submerged arc welding (SAW) to ensure strength.
Machining: Precision machining for proper alignment of rails and trolley.
Legs & End Carriages
Welded and machined for smooth wheel and rail movement.
Installation of rail tracks for trolley motion.
4. Assembly of Mechanical & Hoisting Components
Trolley & Hoist System
Gearbox, motor, drum, rope guide, and safety brakes are assembled.
Wire rope is wound on the drum.
Drive Mechanism Installation
Motors and reducers are installed on the end carriages.
Wheels are assembled with proper alignment to ensure smooth movement.
5. Electrical System Installation
Control Panel Assembly: Includes VFD, contactors, and safety relays.
Wiring & Connections: Motor wiring, limit switches, and emergency stop system.
Remote Control & Cabin Installation: Depending on client requirements, either a radio remote control or operator cabin is installed.
6. Testing & Quality Control
Mechanical Testing:
Load testing with 1.25 times the rated capacity.
Checking trolley movement and hoisting performance.
Electrical Testing:
Verification of motor speeds, limit switches, and control panel operations.
Emergency brake function tests.
Safety Inspections:
Ensuring compliance with OSHA, ISO, or local safety regulations.
7. Surface Treatment & Painting
Sandblasting: Removes rust and prepares metal surfaces.
Priming & Painting: Corrosion-resistant epoxy primer followed by industrial-grade paint.
8. Packaging & Transportation
Component Packing: Each part is securely packed for transport.
Loading & Shipping: Loaded onto trucks or containers for delivery.
9. Installation & Commissioning
On-site Assembly: Main components are bolted and welded into place.
Final Testing: Load testing at the installation site to ensure full functionality.
Handover & Training: Operator training and final approval from the client.
10.Final Deliverables
Complete Gantry Crane System with operational manuals.
Warranty & After-Sales Support for long-term maintenance.

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%.