Double Girder Trolley Gantry Crane
Products Description
The Double Girder Trolley Gantry Crane is a heavy-duty lifting system designed for efficient material handling in environments where high load capacity, wide span, and precise load positioning are required. It consists of two parallel main girders supported by legs that move on ground rails, and a trolley-mounted hoist that runs along the top of the girders.
This crane is ideal for outdoor or semi-outdoor applications where overhead cranes are not feasible, such as construction yards, steel plants, logistics terminals, and shipyards.
🔍 Key Features:
Configuration: Double girder structure with a trolley and hoist mechanism
Lifting Capacity: Typically ranges from 5 tons to 300+ tons
Span Range: Up to 40 meters or customized
Lifting Height: Up to 30 meters or based on project needs
Duty Class: A5–A7 (medium to heavy-duty usage)
🚧 Design Characteristics:
Double Girders: Offer higher strength, better load distribution, and longer spans compared to single girder types.
Trolley Hoist Mechanism: Moves along the rails on top of the girders, allowing precise lateral and vertical positioning of loads.
Gantry Legs: Support the structure and connect to rail-mounted end carriages for crane travel.
Drive System: Independent motorized drives for hoisting, trolley, and crane movement with optional frequency conversion control.
📦 Typical Applications:
Heavy manufacturing plants
Steel mills and fabrication yards
Precast concrete plants
Railway yards and container terminals
Shipbuilding and port handling operations
Power generation and large-scale assembly facilities
🎮 Control Options:
Cabin Control
Pendant Control
Wireless Remote 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
Pictures & Components
1.Main Girders (Double Girders)
Structure: Welded box-type or truss-type steel beams
Function: Serve as the primary support for the trolley hoist and distribute loads evenly
Features: Fitted with rails on top for trolley travel; designed for long spans and high strength
Functions
Support for Lifting Mechanism: It houses the trolley and hoist that carry out lifting tasks.
Stability: Ensures the stability of the crane by evenly distributing loads.
Efficiency: Designed to optimize load movement across the working area.
Design Considerations
Load Requirements: Calculated based on the maximum load and dynamic forces the crane will encounter.
Span and Height: Dictated by the size of the workspace and the required lifting height.
Safety Factors: Includes features like deflection limits, fatigue resistance, and compliance with industry standards (e.g., FEM, CMAA).
Gantry Legs (Supports)
Design: A-frame or U-frame depending on height and clearance needs
Material: Steel welded box-type or tubular sections
Function: Transmit the load from girders to the ground rails via end carriages
2. Trolley with Hoisting Mechanism
Trolley Frame: Compact steel structure that moves along the top of both girders
Hoist Mechanism: Includes:
Motor & Gearbox
Wire rope drum
Hook block or lifting beam
Brake system
Function: Provides vertical lifting and lateral movement for precise load handling
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3.End Carriages (End Beams)
Structure: Connects main girders to the crane legs
Function: Houses wheels and drive mechanisms for crane travel
Wheel Types: Driven and idle wheels; with double-flanged design for rail tracking
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4.Crane Traveling Mechanism
Drive System: Motor + gearbox + wheels
Function: Moves the entire gantry crane along the ground rails
Features: Includes brake units, buffer devices, and anti-skewing systems for smooth, aligned operation
5.Trolley travelling mechanism
1) Structural composition
Trolley frame: The frame is typically made of high-strength steel to support the load and withstand the stresses during operation.
Wheel set: The trolley is equipped with wheels that run on the rails of the main girder. These wheels are often made of hardened steel or cast steel to ensure durability and wear resistance.
Drive device: Electric motors are commonly used to provide the necessary power for the trolley's movement A gearbox is used to control the speed and torque of the trolley's movement.Couplings connect the motor to the gearbox and ensure smooth transmission of power to the wheels.
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2) Function of the trolley operating mechanism
Horizontal Movement: The primary function of the trolley traveling mechanism is to move the trolley horizontally across the length of the main girders. This movement allows the crane to position the hoist over a desired load location.
Load Handling: By moving along the main girders, the trolley helps in positioning the hoist system accurately above the load, which is necessary for lifting and transferring goods efficiently.
Power Transmission: The traveling mechanism typically uses electric motors and gear systems to provide the necessary torque and speed for the trolley's movement. The motors can be either AC or DC, depending on the design and requirements of the crane.
Rails and Wheels: The trolley runs on rails that are mounted on the main girders. The wheels on the trolley are designed to travel along these rails, ensuring smooth and stable movement. The wheels may be fitted with flanges to prevent lateral movement and maintain alignment.
Safety Mechanisms: The traveling mechanism is equipped with safety features such as limit switches, braking systems, and overload sensors to prevent accidents and ensure the safe operation of the crane.
6.Crane wheel
1) Function of wheels
Load Bearing: In a double main girder gantry crane, each wheel supports a significant portion of the crane's load. The wheels must be engineered to handle both the static and dynamic loads imposed during lifting operations.
Material Handling and Safety: The design of crane wheels must ensure safe operation, especially when handling heavy or oversized loads. The wheels should be engineered to minimize noise and vibrations during operation.
Rail Compatibility: Crane wheels are designed to run on specific rail types (e.g., flat or curved tracks). The size and shape of the wheel flange must match the rail profile to ensure proper fit and smooth operation.
2) Design requirements
Material and Design: Crane wheels are typically made of high-strength steel or cast iron to withstand the heavy loads and stresses associated with lifting and transporting materials. The design often includes a flange to ensure proper alignment and prevent the wheels from derailing off the tracks.
7.Crane Hook
The crane hook of a double main girder gantry crane is an essential component used for lifting and transporting heavy loads.
Design and Structure
Material: Typically made of high-strength steel to withstand heavy loads and provide durability.
Shape: The hook often has a C-shape or a pointed end for securely holding lifting slings or chains.
Size and Capacity: It is designed to match the lifting capacity of the crane, which can range from a few tons to several hundred tons for large industrial cranes.
Types of Hooks
Single Hook: Common in standard applications, used for lifting a load from a single point.
Double Hook: Utilized when a more balanced load is needed, often in double main girder designs for higher lifting capacities.
Crab Hook: In gantry cranes, the hook may be mounted on a trolley or crab that runs along the girders.
Motor
The motor of a double main girder gantry crane is an essential component that provides the power necessary for lifting, traveling, and sometimes rotating the crane's hoist or trolley system.The motor's power rating must match the crane's capacity and the load it needs to lift. Typically, these motors range from a few kilowatts up to hundreds of kilowatts, depending on the lifting and traveling requirements.
Motors can be equipped with variable frequency drives (VFDs) for smooth speed adjustments and energy savings.Safety and control systems like overload protection, braking systems, and emergency stops are incorporated for safe operation.
The motor should be compatible with the electrical supply available at the operating site, which can vary (e.g., 380V/50Hz, 480V/60Hz).The motor in a double main girder gantry crane is used for operations such as lifting heavy loads, moving the crane along the tracks (longitudinal travel), and sometimes lateral movement (cross travel) of the hoist or trolley.
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Sound and light alarm system & limit switch
1) Sound and light alarm system
A double main girder gantry crane, commonly used in heavy-duty operations, often incorporates safety mechanisms like sound and light alarm systems to ensure safe operations.
Sound Alarm (Horns/Buzzers): These are typically loud, audible devices that emit a distinctive sound to alert people in and around the working area. The sound level is designed to be high enough to be heard over operational noise.
Light Alarm (Flashing Lights/Beacons): Visual signals, such as flashing lights or rotating beacons, help alert personnel visually, especially in noisy environments where sound alarms may be insufficient.
2) Limit switch
A limit switch on a Double Main Girder Gantry Crane is a safety device used to prevent the crane from moving beyond a designated range. This ensures the protection of both the crane and its surroundings, as well as any loads being lifted.
Key Functions of Limit Switches:
Position Control: The limit switch helps monitor and control the position of the crane's trolley, hoist, and gantry to prevent over-travel and collisions.
Safety Shutdown: If the crane moves past its allowed limits, the limit switch signals the control system to stop the motor and prevent damage or hazardous situations.
Emergency Stop: It can act as an emergency cutoff to shut down the crane when it approaches the limits of its track or rail, preventing it from derailing or causing accidents.
Types of Limit Switches Used:
Mechanical Limit Switches: Activated by physical contact, often using a lever or cam that triggers the switch when moved by the crane's motion.
Electronic Limit Switches: Use sensors (e.g., inductive, capacitive, or optical sensors) for non-contact detection, providing higher durability and reducing wear and tear.
Rotary Limit Switches: Typically used in applications where rotational motion needs to be monitored, such as in hoists.
Linear Limit Switches: Used for applications where linear travel is monitored, commonly found in the movement of the trolley.
10.Safety Devices
1) 1. Overload Protection Device
Function: Prevents the crane from lifting loads that exceed its rated capacity.
2. Limit Switches
Function: Prevents the crane from moving beyond a set range during operations.
3. Emergency Stop Button
Function: Allows operators to quickly shut down the crane in case of an emergency.
4. Anti-Collision Device
Function: Prevents collisions between the crane and other structures or equipment.
5. Load Sway Control
Function: Reduces load sway during operations, which can be dangerous if uncontrolled.
6. Brake Systems
Function: Ensures that the crane remains in a stationary position when not in motion.
7. Safety Interlocks
Function: Prevents the operation of the crane if certain safety conditions are not met.
8. Warning Alarms and Signal Lights
Function: Alerts personnel in the vicinity of the crane's movement.
9. Anti-Tipping Device
Function: Protects against crane tipping due to uneven load distribution or excessive loading.
10. Cooling System for Motors
Function: Prevents motors from overheating during extended use.
11. Remote Control Systems
Function: Allows operators to control the crane from a safe distance.
12. Crane Monitoring Systems
Function: Provides real-time monitoring of operational parameters such as load weight, speed, and position.
13. Lighting and Visibility Aids
Function: Ensures that the operator has clear visibility, especially in low-light conditions.
11.Control Mode
1)1. Pendant Control
Description: The crane operator uses a wired control pendant to manage the movement of the crane and hoist.
Advantages: Simple to use, cost-effective, and provides direct control from a safe distance.
Usage: Commonly used in stationary or semi-stationary operations where the operator can be close to the crane.
2. Radio Remote Control
Description: Operators use a wireless control unit, which communicates with the crane via radio signals.
Advantages: Offers more flexibility as the operator can control the crane from a greater distance and access hard-to-reach areas.
Usage: Ideal for more complex operations and environments where operator mobility is essential.
3. Cabin Control
Description: The operator sits in a cabin on the crane itself and controls it using a combination of joysticks, buttons, or other controls.
Advantages: Provides a better view of the working area and greater precision in controlling the crane.
Usage: Suitable for heavy-duty operations or when a higher level of control is needed for positioning and maneuvering.
4. Automated Control (Semi-Automatic and Fully Automated)
Description: The crane can be controlled by programmed commands or integrated with automated systems for autonomous operation.
Advantages: Reduces human intervention, improves precision, and enhances safety for repetitive tasks.
Usage: Often used in large-scale operations where high efficiency and continuous operation are necessary.
5. Hybrid Control
Description: Combines manual operation (using pendant, remote, or cabin control) with automated features that can be engaged as needed.
Advantages: Offers versatility for operators who need to switch between manual and automated modes for specific tasks.
Usage: Common in systems designed to be adaptable to various operational requirements.
12.Sketch
Main technical
Advantages
1. High Load Capacity
The double girder design allows for greater lifting capacity, typically ranging from 10 tons up to 300+ tons.
The trolley runs on rails mounted on top of the girders, enabling it to carry heavier and more balanced loads.
🏗️ 2. Long Span and High Lift
Can support longer spans (up to 40 meters or more) and higher lifting heights, making it suitable for large outdoor yards or wide workshops.
Provides excellent coverage area for handling oversized items.
⚙️ 3. Superior Structural Strength and Stability
Twin girders offer enhanced structural rigidity, reducing deflection under load and improving crane durability.
Better resistance to torsional and lateral loads compared to single girder cranes.
🎯 4. Precise and Smooth Operation
Equipped with a trolley-mounted hoist, enabling accurate lateral and vertical positioning of heavy loads.
Optional inverter drives (VFD) provide smooth acceleration/deceleration and reduce mechanical stress.
🔁 5. Versatile Applications
Suitable for indoor and outdoor use, and adaptable to a variety of industries including:
Steel plants
Construction yards
Shipyards
Manufacturing and logistics
Power stations
🛠️ 6. Easy Maintenance and Accessibility
Components such as the hoist, motors, and control systems are easily accessible for inspection and servicing.
Modular design allows for quick part replacement and upgrade.
🔋 7. Multiple Power and Control Options
Can be powered by cable reel, festoon system, or conductor rail (busbar).
Offers remote control, pendant, or cabin operation based on operational needs and safety requirements.
🛡️ 8. Enhanced Safety Features
Comes with built-in overload protection, limit switches, emergency stop functions, and anti-collision systems.
Optional wind-proof anchoring and rail clamps for outdoor applications.
💰 9. Cost-Effective for Heavy Lifting
Eliminates the need for complex building structures like overhead runways.
More economical than building an overhead crane runway in large open yards.
Application
1. Steel Industry
Applications:
Handling steel coils, billets, plates, and beams
Loading/unloading raw materials and finished products
Environment: Steel mills, fabrication plants, storage yards
🧱 2. Precast Concrete and Construction Sites
Applications:
Lifting and transporting precast beams, slabs, and bridge segments
Assembly and positioning of heavy structural components
Environment: Precast yards, highway bridge projects, infrastructure sites
⚙️ 3. Heavy Equipment and Machinery Manufacturing
Applications:
Moving large machine parts, dies, molds, and assemblies between workstations
Final assembly of oversized equipment or machinery
Environment: Equipment manufacturing plants, assembly workshops
🚢 4. Shipbuilding and Marine Yards
Applications:
Transporting ship hull sections, engines, and steel panels
Handling heavy blocks during modular ship assembly
Environment: Dockyards, ship fabrication shops, ports
🚛 5. Logistics and Container Yards
Applications:
Lifting and stacking heavy cargo or containers
Moving oversized freight from railcars or trucks
Environment: Intermodal terminals, freight depots, open yards
⚡ 6. Power Plants and Energy Projects
Applications:
Handling turbines, transformers, generators, and pipelines
Lifting heavy equipment during plant construction and maintenance
Environment: Hydropower stations, wind farms, thermal plants
🏭 7. Warehouses and Industrial Storage Yards
Applications:
Stacking large inventory items in wide, open areas
Loading/unloading trucks and railcars
Environment: Bulk storage yards, industrial warehouses
🛠️ 8. Mining and Metallurgy
Applications:
Transporting mining equipment, ore containers, and crushers
Maintenance support for large-scale processing machinery
Environment: Open-pit mines, smelting plants, mineral yards
Crane production procedure
1. Design and Engineering
Blueprint and Structural Design: Engineering teams design the crane based on specifications, considering the weight, span, lifting capacity, and working environment.
Component Specifications: Detailed specifications for components such as the main girders, end beams, hoist system, trolley, and electrical components are prepared.
2. Material Selection and Procurement
Steel Material Selection: High-strength steel materials are chosen for the main girders, columns, and other critical parts.
Procurement: Materials, such as steel plates, sections, bolts, and electrical components, are sourced and inspected for quality.
3. Cutting and Pre-Fabrication
Cutting and Shaping: Steel components are cut, shaped, and welded into preliminary forms according to the design specifications.
Pre-Fabrication Assembly: Components such as beams and girders are pre-assembled to verify that they fit together properly.
4. Welding and Structural Assembly
Welding: Main girders, columns, and other structural components are welded to create a sturdy framework. Specialized welding techniques are used to ensure strength and durability.
Structural Assembly: The main girders and end beams are assembled, ensuring precise alignment for balanced load distribution.
Quality Control: Welding seams and joints are inspected using non-destructive testing (e.g., ultrasonic or X-ray testing) for any structural defects.
5. Machining and Finishing
Machining of Parts: Critical parts such as the wheels, trolley components, and hoists undergo machining for proper fitting and smooth operation.
Surface Treatment: Steel parts are cleaned and subjected to surface treatments like sandblasting and coating to prevent rust and enhance durability.
Painting and Coating: Protective coatings are applied for weather resistance, with a primer followed by top coats.
6. Assembly of Crane Components
Main Girder Assembly: The two main girders are mounted and aligned.
End Beam Installation: End beams are fixed to the main girders, forming the frame of the crane.
Hoist and Trolley Installation: The hoist mechanism and trolley are mounted on the main girder rails and tested for alignment and operational smoothness.
7. Electrical and Control Systems Installation
Wiring and Cabling: Electrical wiring is installed for power supply, control circuits, and safety systems.
Control Panel and Safety Features: The control panel is mounted, with safety features such as limit switches, emergency stops, and overload protection integrated and tested.
Control System Programming: The crane's control system is programmed and tested for correct operation.
8. Testing and Quality Assurance
Load Testing: The crane is subjected to load tests to ensure it can handle its rated capacity without issues.
Operational Testing: Functional tests are performed to check movements, responsiveness, braking systems, and electrical operations.
Inspection and Certification: The crane undergoes final inspections to verify compliance with safety regulations and standards. Certification may be issued by relevant authorities.
9. Final Adjustments and Delivery Preparation
Final Adjustments: Any minor adjustments are made to ensure smooth operation.
Documentation: Operation manuals, maintenance guidelines, and certification documents are prepared for delivery.
Packaging and Shipping: The crane is packaged securely for shipment, ensuring all parts are protected during transit.
10. Installation and Commissioning (at Site)
On-site Assembly: The crane is assembled at the customer's location if required.
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%.
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