Mg Type Double Girder Gantry Crane

 

Key Features of MG-Type Double Girder Gantry Crane:

Double Girder Design

Two main girders provide higher load capacity and better stability compared to single girder cranes.

Suitable for heavy-duty lifting (typically 5 tons to 500 tons or more).

Gantry (Portal) Structure

Supported by two legs (rigid or flexible) that move on rails or wheels.

Can be semi-gantry (one leg supported on a building column) or full gantry (both legs on ground rails).

Hoisting Mechanism

Equipped with an electric hoist or wire rope winch for lifting.

Can include auxiliary hoists for lighter loads.

Travel Mechanism

Crane travel: Movement of the entire gantry along rails.

Trolley travel: Movement of the hoist along the bridge girders.

Lifting motion: Vertical movement of the load.

Control System

Operated via pendant control, radio remote control, or cabin control.

Can be customized for automated operations.

 

Comparison with Other Gantry Cranes:

Feature	MG Double Girder	Single Girder	Rubber-Tired Gantry (RTG)
Load Capacity	High (up to 500T+)	Medium (up to 20T)	Medium (up to 50T)
Stability	Very High	Moderate	Moderate
Mobility	Rail-mounted	Rail-mounted	Rubber tires (no rails)
Cost	Higher	Lower	Medium

Warranty :1 Year

Weight (KG):35000 kg

Feature:Gantry Crane

Application:Railway Station/Sea Port/Yard/Subway

Rated Lifting Moment:Different

Material: Q235/Q345

Working Temperature:-40~40 ℃

Legs space:Bigger than normal

Control:Cabin control

Electrical parts:Schneider

Power Source:380~480V, 50hz/60hz

Power supply:M5~M8 (ISO)

Main electrical parts:Schneider Brand

Crane feature:High Efficiency

 

A MG-type double girder gantry crane consists of several key structural and mechanical components that work together to ensure safe and efficient lifting operations. Below is a detailed breakdown of its major components:

 

1. Main Structural Components

A. Bridge Girders (Double Girder)

Two parallel box girders or truss girders that form the main horizontal beam.

Designed to withstand bending and torsional forces.

Usually made of high-strength steel (Q235B/Q345B).

 

 

B. End Carriages (Legs)

Support the bridge girders and transfer loads to the runway rails.

Can be rigid-leg (fixed) or flexible-leg (allows slight movement).

Equipped with wheel assemblies for movement.

C. Trolley Frame

Moves along the bridge girders and carries the hoisting mechanism.

Includes wheels, motors, and brakes for transverse motion.

 

D. Runway System

Rails installed on the ground or elevated structure for crane movement.

Includes rail clamps to prevent unwanted movement.

2. Lifting & Motion Mechanisms

A. Hoisting Mechanism

Electric Hoist / Wire Rope Winch – Lifts and lowers the load.

Hook Block – Connects to the load via slings or chains.

Drum & Rope – For wire rope winding (in winch systems).

Load Limiter – Prevents overloading.

B. Trolley Travel Mechanism

Trolley wheels – Move along the bridge girders.

Drive motor & gearbox – Powers the trolley movement.

Brakes – Ensure smooth stopping.

C. Gantry Travel Mechanism (Long Travel)

Wheels & Buffers – Move the entire crane along the runway rails.

Drive motors (usually 2 or 4) – Provide synchronized movement.

Rail sweeps – Clear debris from the track.

3. Electrical & Control Systems

A. Power Supply

Festoon system / Cable reeling drum – Delivers electricity to moving parts.

Slip rings (for rotating cranes).

B. Control System

Pendant control (wired) – Handheld remote.

Radio remote control – Wireless operation.

Operator cabin – For cabs with joystick/button controls.

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C. Safety Devices

Limit switches (for hoisting, trolley, and gantry travel).

Anti-collision system (for multiple cranes).

Emergency stop button.

Anemometer (for wind detection in outdoor cranes).

4. Auxiliary Components

Walkways & ladders – For maintenance access.

Lighting system – For night operations.

Bumpers & buffers – Absorb impact during movement.

Lubrication system – For gears and bearings.

SKETCH

Main technical

 

The MG-type double girder gantry crane is a robust and versatile lifting solution, offering several key benefits over single girder and other gantry crane types:

1. High Load Capacity (Up to 500T+)

Double girders provide superior strength, making it ideal for heavy-duty lifting in industries like steel, shipbuilding, and construction.

More stable than single girder cranes, reducing deflection under heavy loads.

2. Greater Span & Lifting Height

Can cover wide work areas (span up to 35m or more).

Higher hook height due to the top-mounted hoist system (unlike underhung single girder cranes).

3. Enhanced Durability & Stability

Rigid steel construction withstands harsh environments (ports, foundries, outdoor yards).

Better resistance to side loads and dynamic forces compared to single girder cranes.

4. Flexible Movement & Positioning

Runs on ground rails (unlike overhead cranes, which require building support).

Can be semi-gantry (one leg on a building column) or full gantry (both legs on ground rails).

5. Customizable for Specialized Applications

Can be fitted with magnetic lifts, grabs, spreader beams, or rotating hooks.

Options for explosion-proof, anti-sway, or automated controls.

6. Lower Long-Term Maintenance Costs

Heavy-duty components (wheels, motors, girders) have a longer lifespan than single girder cranes.

Easier access for maintenance & inspections due to walkways and service platforms.

 

1. Heavy Industries & Manufacturing

Steel plants (handling coils, slabs, molds).

Foundries & forging shops (lifting molten metal ladles).

Machinery assembly (positioning heavy components).

2. Ports & Logistics

Container handling (loading/unloading ships, stacking containers).

Bulk material handling (using grabs for coal, ore, grain).

3. Railway & Shipbuilding

Locomotive maintenance (lifting train engines & wagons).

Shipyards (moving ship sections, engines, and large components).

4. Power Plants & Construction

Hydroelectric/Nuclear plants (installing turbines, generators).

Bridge & dam construction (lifting precast segments).

5. Scrap Yards & Recycling

Equipped with electromagnetic lifts or grapples for scrap metal handling.

 

 

1. Design and Planning

Demand Analysis: According to customer needs and usage scenarios, a detailed demand analysis is carried out to determine the specifications, load, span, lifting height, etc. of the crane.

Engineering Design: Engineers use CAD and other design software to carry out detailed design, including structural, mechanical, electrical and other aspects to ensure that the design meets relevant standards and specifications.

2. Material Procurement

Material Selection: Select appropriate steel, motors, control systems and other components according to design requirements.

Supplier Screening: Screen suppliers of materials and components to ensure the quality and reliability of materials.

3. Processing and Manufacturing

Cutting and Forming: Cut, weld, bend and other processes on steel to form main beams, end beams and other structural components.

Machining: Precision machining of key components, such as turning, milling, drilling, etc., to ensure that the size and accuracy meet the design requirements.

Surface Treatment: Spray, galvanize or rust-proof metal parts to enhance corrosion resistance and aesthetics.

4. Assembly

Component Assembly: Assemble the main beam, end beam, trolley, lifting mechanism and other components to form a complete crane structure.

Installation of electrical system: Install electrical equipment such as motors, control cabinets, sensors, limit switches, etc. to ensure the normal operation of the electrical system.

5. Debugging and testing

Preliminary debugging: Carry out preliminary debugging of the crane to check the coordination and operation of each component.

Load test: Carry out load test to ensure the safety and stability of the crane under rated load, and test the functions of safety devices such as overload protection and limit switches.

Performance test: Test the performance indicators of the crane such as lifting speed, running speed, braking effect, etc. to ensure that they meet the design requirements.

6. Quality inspection

Quality inspection: Carry out a comprehensive quality inspection of the crane, including appearance, size, performance, etc., to ensure compliance with relevant standards.

Safety assessment: Carry out safety assessment to ensure the normal operation of all safety devices and systems.

7. Delivery and installation

Packaging and transportation: Pack qualified cranes and prepare them for transportation to the customer site.

On-site installation: Carry out on-site installation according to customer requirements, including basic production and equipment debugging.

Training and handover: Train operators to ensure that they master the operation methods and safety precautions of the equipment and complete the handover work.

 

 

 

 

 

 

 

Material Inspection

Quality Inspection: Strict quality inspection is carried out on the purchased raw materials to ensure that they meet the design requirements and national standards.

Material Storage: Qualified materials are stored according to classification to prevent corrosion or damage.

Cutting and Forming

Steel Cutting: Use plasma cutting, laser cutting or flame cutting and other technologies to cut the steel according to the size of the design drawing.

Forming Processing: Form the steel plate through bending, rolling, welding and other processes to manufacture the main beam, end beam and other structural parts.

Welding

Component Welding: The cut and formed steel parts are welded into the main structures such as the main beam, end beam and trolley. The welding process needs to be strictly controlled to ensure the structural strength and welding quality.

Weld Inspection: Use non-destructive testing technology (such as ultrasonic testing, radiographic testing) to inspect the welds to ensure that there are no cracks or other defects.

Machining

Precision Machining: Precision machining is performed on the key components of the crane, such as wheel sets, bearing seats, pulleys, etc., to ensure their dimensional accuracy and surface quality.

Assembly of the whole machine

General assembly: On the basis of pre-assembly, the overall assembly of the crane is carried out, including the final installation of the main beam, end beam, lifting mechanism, walking mechanism, etc.

Commissioning and testing

Under dynamic conditions, the operating performance of the crane is tested, including the testing of lifting, walking, steering and other functions. The overall size of the assembled bridge crane is checked to ensure that all dimensions meet the design requirements.

Spraying and anti-corrosion treatment

Surface treatment Rust removal: Rust removal on the surface of the crane, common methods include sandblasting, pickling, etc. Primer spraying: Spray anti-corrosion primer on the treated surface to prevent metal oxidation and corrosion. Topcoat spraying Color spraying: Spray topcoat according to customer requirements or industry standards to give the crane a protective and decorative effect. Marking: After spraying, mark the crane's identification information in accordance with the specifications, such as model, rated load, etc.

Factory and installation

Packaging and transportation

Packaging protection: Protectively package the key components of the crane to prevent damage during transportation. Transportation arrangement: According to the equipment size and transportation conditions, select a suitable transportation method to transport the crane to the customer's site.

Acceptance and delivery

Customer acceptance

On-site acceptance: The customer conducts on-site acceptance of the crane according to the contract requirements and technical specifications to check the performance and quality of the equipment.

Problem rectification: If any problems are found, the manufacturer needs to rectify them in time to ensure that the equipment fully meets the customer's requirements. Delivery and use Operation training: The manufacturer usually trains the customer's operators to ensure that they can operate the crane correctly and safely.

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