50 Ton 100 Ton Mg Double Girder Gantry Crane

 

50 Ton / 100 Ton MG Double Girder Gantry Crane – Introduction

The MG double girder gantry crane is a robust, high-capacity lifting system designed for outdoor and indoor applications requiring the handling of extremely heavy and bulky materials. With lifting capacities of 50 tons and 100 tons, these cranes are essential equipment in industries such as shipbuilding, steel fabrication, railways, construction, and logistics yards.

Key Features:

Lifting Capacity: 50 tons or 100 tons

Structure Type: MG model (double girder gantry)

Span: Customizable, typically ranges from 18m to 35m+

Lifting Height: Can range from 6m to 18m or more depending on site needs

Trolley & Hoist: Mounted between girders, providing better hook approach and lifting height

Working Class: A5–A7 (medium to heavy-duty usage)

Power Supply: Cable reel or busbar system

Main Components:

Double girders for enhanced load distribution and rigidity

A-frame or box-type legs for stable ground support

Trolley with heavy-duty hoist or winch

Motorized end carriages that allow crane movement on ground-level rails

Advanced electrical systems with overload protection, emergency stops, and limit switches

Cabin or remote controls for safe and flexible operations

Applications:

Steel mills and heavy fabrication plants

Container yards and ports

Railway engineering yards

Precast concrete yards

Shipyards and marine engineering

Wind turbine component handling

Advantages:

Superior strength and load capacity for large, heavy materials

Customizable for span, height, and speed

Stable and efficient operation over long working hours

Suitable for harsh outdoor environments with weather protection

Equipped with modern control and safety systems

 

 

1.Double Main Girders

Two large, parallel steel beams forming the crane's main load-bearing structure.

Fabricated as box-type welded structures for maximum strength and durability.

Supports the trolley and distributes weight evenly.

Supporting Legs

Heavy-duty A-frame, U-type, or box-type legs connecting the main girders to the ground rails.

Can be asymmetrical for better clearance or material handling needs.

Equipped with ladder, platform, and maintenance access areas.

 

Trolley with Hoisting Mechanism

Travels along the top of the two main girders.

Includes:

Lifting winch or wire rope hoist

Reducer, brake, and motor

Drums and sheaves for wire rope handling

Allows for precise lifting and cross-travel movement.

 

3.End Carriages / Crane Traveling Mechanism

Located at the base of each leg.

Includes motorized wheels that run on ground-level rails.

Drives the crane longitudinally across the work area.

Equipped with brakes, buffers, and rail clamps for stability and safety.

 

 

4.Crane travelling mechanism

1) Working principle

The traveling mechanism is powered by electric motors connected to gearboxes, which provide the torque necessary for movement.

Drive wheels are mounted on the legs of the crane. These wheels roll along the rails on the ground or on elevated tracks, depending on the crane design.The wheels are typically driven by electrical motors through a system of reduction gears that adjust the speed and torque for smooth and controlled movement.

2) Functions of the crane operating mechanism

Movement along the Rails:The primary function of the traveling mechanism is to move the gantry crane along the crane rails installed on the ground or structure. This allows the crane to cover the entire working area, moving materials and loads from one point to another.

Support for the Gantry Structure:The traveling mechanism supports the entire gantry structure, which includes the main beam and cantilever. This support ensures stability and the safe operation of the crane during movement.

Lifting Load:As the gantry crane moves, the traveling mechanism facilitates the movement of loads horizontally, providing an effective means for lifting and transporting heavy materials across the working area.

Adjustable Speed and Positioning:It provides the ability to control the speed and positioning of the crane, which is crucial for precision in handling materials and ensuring safe operations.

Integration with Other Mechanisms:The crane traveling mechanism works in coordination with other components such as the hoisting mechanism and trolley system to enable efficient lifting and movement of loads.

Safe Operation and Stability:The traveling mechanism ensures smooth, safe movement of the crane along the rails, minimizing risks associated with jerky or unstable movement that could damage equipment or compromise safety.

Powered by Motors:The mechanism is typically powered by electric motors or hydraulic systems that provide the necessary power for movement. These motors are designed to offer reliable operation under heavy loads.

5.Trolley travelling mechanism

1) Structural composition

Trolley frame: The frame is the main structural support of the trolley, providing the necessary rigidity and strength to bear the load.It is typically made of high-strength steel to ensure durability and resistance to deformation under heavy loads.

Wheel set: The wheels are often mounted on axles, and the bearings inside these wheels are designed for high load-bearing capacity and smooth operation.

Electric Drive Motor: The trolley's movement is powered by an electric motor, which drives the wheel system via a gearbox and a system of pulleys or chains.The motor is typically installed on the trolley frame and is connected to the wheels through a drive mechanism, allowing for both forward and backward motion.

2) Function of the trolley operating mechanism

1. Horizontal Movement of the Hoist

The trolley, which carries the hoisting mechanism, moves horizontally along the gantry rail. This horizontal movement enables the crane to lift and lower materials over a large area, such as a yard, dock, or warehouse.

2. Smooth and Precise Positioning

The trolley traveling mechanism is designed for precise control of the trolley's position. This is critical for ensuring that loads are picked up and placed accurately at the desired locations.

3. Support for the Hoisting Mechanism

The hoist system is typically mounted on the trolley. The trolley traveling mechanism allows the hoist to traverse the length of the gantry, ensuring that the lifting equipment can cover the full area needed for operations.

4. Load Distribution and Stability

The trolley helps distribute the load evenly across the crane's structure. As the trolley moves, the load is kept stable, reducing the risk of imbalance that could lead to accidents.

5. Speed Control

The trolley traveling mechanism includes motors, gears, and sometimes variable frequency drives (VFDs), which provide the necessary speed control for the trolley's movement. This helps in adapting to different operational needs, whether moving slowly for precision or quickly for efficiency.

6. Integration with Other Crane Movements

The trolley traveling mechanism is integrated with the gantry's vertical (hoisting) and longitudinal (gantry traveling) movements. It works in coordination with these functions to ensure smooth and synchronized operation, making it easier to perform complex lifts and transfers of materials.

7. Safety and Load Handling

The mechanism often includes safety features, such as limit switches or sensors, to prevent the trolley from exceeding its operational boundaries or colliding with obstacles, enhancing the safety of the entire crane operation.

6.Crane wheel

1) Function of wheels

The wheels provide support for the crane structure and are essential for allowing the gantry crane to travel along its track.They also absorb the forces generated by the crane's weight and operational movements, distributing these forces to prevent damage to the track and other crane components.

Depending on the crane's purpose and the loads it handles, the wheels are engineered to handle different weight capacities. Larger cranes or those used for heavier lifting will have larger, more robust wheels.

2) Design requirements

Crane wheels are typically made of high-strength steel or alloy materials to withstand the weight of the crane and its load while enduring constant motion and heavy loads.The wheels are often designed with a flange to ensure smooth and stable movement along the rails and to prevent them from derailing.

7.Crane Hook

The crane hook of a cantilever gantry crane is an essential component in the lifting and handling process. This hook is used to attach and support loads during hoisting operations.

The hook is typically made of high-strength steel to handle heavy loads. It has a curved shape, with a deep throat for secure attachment to slings, chains, or other lifting devices.The hook usually has a safety latch to prevent the load from accidentally coming loose during operation.

The primary function of the crane hook is to connect the crane's lifting mechanism (such as the hoist) with the load. It moves along the gantry crane's beam (which is supported by the legs of the gantry structure) and can be raised or lowered depending on the lifting requirements.

Motor

The motor of a cantilever gantry crane is a crucial component responsible for driving the various movements of the crane, such as the hoisting, trolley travel, and gantry movement. Depending on the design and size of the crane, the motor can vary in type and specifications. The motors are typically controlled by a PLC (Programmable Logic Controller) or VFDs (Variable Frequency Drives) to adjust speeds and torque for efficient operation.

Hoisting Motor:Purpose: Drives the hoist to lift and lower the load.Motor Type: Typically an electric motor, often an AC induction motor.Power: Varies depending on the load capacity, ranging from a few kW to several hundred kW.

Travelling Motor (Trolley Movement):Purpose: Moves the trolley along the gantry rail.Motor Type: Usually a three-phase AC motor.Power: Selected based on the required speed and capacity of the trolley.

Gantry Traveling Motor (Bridge Movement):Purpose: Moves the entire gantry structure along the ground rail, allowing it to span over the load area.Motor Type: A heavy-duty electric motor, often with a variable speed drive (VSD) for fine control.Power: Similar to the trolley motor but typically higher, as it needs to move the entire crane structure.

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Sound and light alarm system & limit switch

1) Sound and light alarm system

The sound and light alarm system for a Cantilever Gantry Crane is designed to enhance safety by providing visual and audible signals in case of abnormal conditions or hazards. These alarms help warn operators, workers, and personnel in the vicinity of potential risks.

Sound Alarm (Horn or Siren):Purpose: Alerts personnel to an emergency or abnormal situation.Sound: Typically loud and attention-grabbing, such as a siren or a horn with varying patterns (continuous, intermittent, or pulsed) to signal different types of alerts.Placement: Usually installed at the crane's control cabin, near the gantry, or at strategic locations where workers are most likely to be present.

Light Alarm (Strobe Light or Flashing Beacon):Purpose: Provides a visual alert that can be seen in areas where sound alone might not be effective (e.g., in noisy environments or at a distance).Light Type: Flashing or rotating strobe lights or beacons are commonly used, often with different colors to indicate different warning levels.

Red: Critical alarm (dangerous situation).

Yellow/Amber: Caution (warning or a non-urgent issue).

Blue: May indicate operational status or a different specific condition.

2) Limit switch

A limit switch on a cantilever gantry crane is a safety device used to prevent the crane from over-traveling or moving beyond its predefined limits. It is an essential component for ensuring the proper and safe operation of the crane. The cantilever gantry crane typically consists of a large structure with a bridge and hoisting mechanism, which is often used in industrial environments like ports or warehouses for lifting and moving heavy loads.

Function of the Limit Switch:

Position Detection: The limit switch detects when the crane's hoist or trolley has reached its designated end position (either fully raised, lowered, or moved along the track). This helps prevent mechanical damage caused by over-travel.

Safety: It acts as a fail-safe to stop the crane from moving if it reaches its boundary. This reduces the risk of accidents and protects both the crane and surrounding equipment.

Automation: Limit switches can be connected to the crane's control system. When the limit switch is triggered, it sends a signal to the control system to stop the crane or reverse its direction.

Types of Limit Switches for Gantry Cranes:

Mechanical Limit Switch: This type uses a physical actuator to open or close contacts when the crane reaches a limit. It is a commonly used, simple, and cost-effective solution.

Magnetic Limit Switch: These use magnetic fields to detect the position of a target without direct contact, providing a more durable and longer-lasting solution.

Proximity Limit Switch: It detects the presence of a target without contact, using a sensor, and is often used in more advanced or higher-speed applications.

10.Safety Devices

Overload limiter

Lifting and traveling limit switches

Emergency stop buttons

Anti-collision systems (for multiple cranes)

Anemometer (wind speed sensor for outdoor operation)

Ground fault protection and phase failure relays

11.Control Mode

1)1. Manual Control

Description: Operators manually control the crane using push-button pendants, levers, or control panels directly on-site.

Features:

Simple to use and maintain.

Suitable for less complex lifting tasks.

Applications: Used in smaller-scale operations or locations with low automation requirements.

2. Remote Control

Description: Operators use a wireless remote control device to operate the crane from a safe distance.

Features:

Improved safety by allowing the operator to stay clear of the load.

Greater operational flexibility.

Can handle more complex movements.

Applications: Warehousing, logistics yards, and other environments requiring higher precision.

3. Cabin Control

Description: The operator sits in a cabin attached to the crane and controls operations using joysticks or control panels.

Features:

Provides the operator with a clear view of the load and working area.

Suitable for heavy-duty and long-duration operations.

Applications: Large-scale industrial sites, such as shipyards, steel mills, or construction sites.

4. Semi-Automatic Control

Description: Some operations (like repetitive movements) are automated, while others require manual input.

Features:

Reduces operator workload.

Increases efficiency for repetitive tasks.

Applications: Assembly lines, logistics hubs, and tasks involving repeated lifting and positioning.

5. Fully Automatic Control

Description: The crane operates autonomously based on pre-programmed instructions or sensor inputs.

Features:

High precision and efficiency.

Eliminates human error and reduces labor costs.

Often integrated with smart systems or IoT for monitoring and data analysis.

Applications: Ports, automated warehouses, and environments requiring high-speed, precise operations.

6. Hybrid Control (Manual + Automatic)

Description: Combines manual and automatic control options, allowing flexibility based on task requirements.

Features:

Adaptable to varying operational needs.

Enhances efficiency without sacrificing control.

Applications: Sites that require both human supervision and automation.

12.Sketch

 

Main technical

 

Advantages of 50t / 100t MG Double Girder Gantry Crane

High Load Capacity

Designed for heavy-duty applications, capable of lifting and transporting large, bulky, or concentrated loads up to 100 tons.

Ideal for steel yards, precast concrete handling, and heavy machinery fabrication.

Strong and Stable Structure

The double girder box-type design offers superior load distribution, increased rigidity, and minimal deflection under load.

Can span large working areas without compromising structural integrity.

Flexible and Customizable

Span, height, hoist speed, and crane travel speed can be tailored to site-specific needs.

Can be equipped with twin trolleys, rotating hooks, or auxiliary hoists for specialized lifting tasks.

Efficient Use of Workspace

Suitable for both indoor and outdoor applications.

Eliminates the need for a fixed overhead structure, maximizing floor space and site flexibility.

Durability in Harsh Environments

Built for outdoor or semi-outdoor operations in shipyards, ports, and heavy industries.

Can include features like weatherproof enclosures, rain covers, wind-resistant structures, and rail clamps.

Advanced Control and Safety Systems

Can be operated via cabin, wireless remote, or pendant control, offering safety and operational flexibility.

Equipped with safety systems such as:

Overload protection

Emergency stop

Travel limiters

Anti-collision and anti-sway systems

Anemometer for wind alerts (for outdoor cranes)

Smooth and Precise Operation

Variable frequency drives (VFDs) enable smooth acceleration, deceleration, and positioning.

Reduced load swing and improved operational accuracy, even at full load.

Cost-Effective for Long-Term Use

Though a larger investment upfront, the MG gantry crane offers long service life, low maintenance requirements, and efficient handling, reducing overall lifecycle costs.

 

 

1. Construction Industry

Lifting heavy construction materials like steel beams, concrete blocks, and other construction components.

Transporting and positioning materials at construction sites.

2. Manufacturing Facilities

Handling large components or machinery in production lines.

Moving raw materials or finished goods within the plant.

3. Shipyards and Ports

Loading and unloading containers or cargo from ships.

Transporting heavy ship components or maintenance equipment.

4. Warehousing and Logistics

Stacking and organizing goods in outdoor or indoor storage areas.

Loading and unloading trucks or railcars.

5. Aerospace and Aviation

Handling large aircraft components, such as fuselages, wings, or engines.

Supporting maintenance and assembly operations.

6. Railway Yards

Lifting and positioning railway components like tracks or bogies.

Loading and unloading railway cargo.

7. Steel Mills and Foundries

Moving heavy steel plates, coils, or castings.

Handling molten metal containers.

8. Mining and Heavy Industries

Transporting heavy equipment and materials in mining operations.

Handling large machinery for assembly or repair.

9. Power Plants

Installing or maintaining turbines, generators, and other heavy power equipment.

Transporting fuel or waste containers in nuclear or thermal plants.

Crane production procedure

1. Design and Engineering

Requirement Analysis

Understand the client's specifications (load capacity, span, height, working environment, etc.).

Determine operational parameters: lifting height, travel speed, working frequency, etc.

Preliminary Design

Create conceptual designs and 3D models.

Choose materials based on strength and environmental conditions.

Detailed Engineering

Develop detailed engineering drawings (structural components, mechanisms, electrical systems).

Perform stress and fatigue analysis to ensure safety.

2. Material Procurement

Source high-quality materials, including:

Steel plates and profiles for structural components.

Motors, gearboxes, and other mechanical parts.

Electrical systems and control components.

Inspect materials to ensure compliance with quality standards.

3. Fabrication

Structural Component Fabrication

Cut, weld, and assemble the steel structures (main girder, cantilever arms, legs, etc.).

Ensure precise alignment and dimensions.

Perform surface treatment (e.g., shot blasting, painting) for corrosion protection.

Mechanical Assembly

Assemble mechanical parts (trolley, hoist, wheels, etc.).

Install motors, gearboxes, and drive systems.

Electrical Assembly

Install electrical components (control panels, cables, sensors).

Wire and connect the system to ensure functionality.

4. Quality Inspection

Material Inspection

Verify material certification and conduct tests (e.g., tensile tests).

Structural Inspection

Inspect weld quality (e.g., ultrasonic testing).

Ensure dimensional accuracy and surface finishing.

Assembly Inspection

Check alignment and functionality of all parts (mechanical and electrical).

Load Testing

Conduct static and dynamic load tests to ensure safe operation.

5. Factory Acceptance Testing (FAT)

Conduct a comprehensive trial run, including:

Full load and overload tests.

Functionality of all safety devices (e.g., limit switches, emergency brakes).

Smooth operation of trolley, hoist, and crane travel.

Document results and obtain client approval.

6. Disassembly and Packing

Disassemble the crane into transportable sections.

Pack components securely to prevent damage during transportation.

Label and prepare a packing list for efficient reassembly.

7. Transportation

Deliver the crane components to the installation site using appropriate transportation methods.

8. Installation and Commissioning

On-Site Assembly

Assemble structural components and mechanical systems.

Install electrical systems and control panels.

Calibration and Testing

Recalibrate the crane system for site-specific conditions.

Perform on-site load testing to verify performance.

9. Handover

Provide training to the client's personnel on safe operation and maintenance.

Deliver technical documentation (user manual, maintenance guide, certificates).

Obtain final approval and acceptance from the client.

10. After-Sales Support

Offer warranty services and maintenance support.

Provide spare parts and technical assistance as needed.

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%.