Mh Type Double Beam Gantry Cranes

What is an MH Type Double Beam Gantry Crane?

An MH Type Double Beam Gantry Crane is a specific classification for a heavy-duty, double girder gantry crane. The "MH" designation typically follows industry standards (like the Chinese JB/T or other national standards) and stands for "Heavy Duty" or "Main Hoist", indicating it is built for more intensive service than a standard-duty crane.

It is a versatile, self-supporting crane that runs on ground-level tracks, featuring two main girders for superior strength and hook height.

 

Advantages of MH Type Double Beam Gantry Cranes

High Capacity & Long Span: Capable of handling loads from 5 tons up to 550+ tons and spanning over 35 meters, making them suitable for wide work areas.

Exceptional Durability: Built with robust components to withstand intensive, frequent use without significant wear.

Maximized Hook Height: The top-running trolley design offers the best possible use of vertical space.

Precision & Stability: The double-girder and rail-mounted design ensures smooth, stable, and precise load control, even at high capacities.

Versatility: Can be equipped with various lifting attachments like hooks, magnets, or grabs to handle diverse materials (coils, containers, machinery, scrap).

 

Comparison: MH Type vs. Other Gantry Cranes

Feature	MH Type (Double Girder, Heavy)	MZ Type (Single Girder, Light)	MG Type (Double Girder, Severe)
Girder Design	Double	Single	Double
Duty Cycle	Heavy (M5/M6)	Light/Moderate (M3/M4)	Very Severe (M6/M7)
Typical Capacity	5 - 550 Tons	1 - 20 Tons	20 - 1000+ Tons
Hook Height	High (Top-Running)	Lower (Under-Running)	Very High (Top-Running)
Cost	High	Economical	Very High
Ideal For	Steel, fabrication, heavy industry	Workshops, warehouses	Steel mills, shipyards, ports

Conclusion: The MH Type Double Beam Gantry Crane is the quintessential heavy-lift gantry solution. It strikes an optimal balance between high capacity, rugged durability, and practical versatility, making it one of the most common and reliable choices for demanding industrial applications where a single-girder crane is insufficient.

 

Lifting Capacity 320 tons
Span (Width) 3 - 12 meters (adjustable)
Lifting Height 3 - 10 meters
Working Class A3-A5 (light to medium duty)
Hoisting Speed 0.5 - 8 m/min (variable)
Main Beam Type Single/double girder (box-type)
Power Supply 220V/380V 3-phase or manual
Control Mode Pendant control/wireless remote
Hoist Type Electric chain hoist/wire rope hoist
Travel Drive Manual push or motorized
Corrosion Protection Hot-dip galvanized or marine-grade paint
Wind Resistance Up to Beaufort scale 6 (for outdoor use)
Operating Temp -20°C to +50°C

Here is a detailed breakdown of the components of an MH Type Double Beam Gantry Crane.

 

1. Primary Structural System (The Backbone)

Double Main Girders: The two primary horizontal beams that form the bridge. For MH type cranes, these are typically robust box girders (fabricated from steel plate) or, less commonly, truss girders. This design provides superior strength, rigidity, and resistance to twisting and sagging under heavy loads and long spans.

End Trucks (Legs): The massive vertical structures at each end of the girders. They house the long travel wheels, drives, and connections to the girders. For heavy-duty MH cranes, legs are often reinforced with A-frames or cross-bracing to provide exceptional stability and prevent leaning when lifting loads off-center.

Crane Rail and Runway System: A critical, fixed infrastructure.

Running Rails: Heavy-duty steel rails (often crane rails) on which the crane travels.

Runway Beams & Foundation: Robust, often reinforced concrete beams and foundations that support the rails and ensure they remain level and aligned under dynamic loads.

 

2. Lifting & Travel System (The Workhorse)

Main Hoist Unit (Heavy-Duty):

Hoist Motor: High-torque, high-duty cycle motor designed for frequent starts and stops under full load.

Wire Rope Drum: Machined drum with precise grooving to spool multiple layers of high-strength wire rope.

Gearboxes: Heavy-duty gears designed to handle shock loads.

Multiple Disc Brakes: Primary and secondary (emergency) braking systems.

 

Auxiliary Hoist: A second, smaller-capacity, faster hoist on the same trolley for handling lighter duties, allowing the main hoist to be reserved for heavy lifts.

Trolley Frame & Drive: The structure that carries the main and auxiliary hoists.

Trolley Travel Drives: Motors, gearboxes, and flanged wheels that move the trolley smoothly along rails on top of the main girders.

Gantry Long Travel Drives: The system that moves the entire crane.

Travel Motors: Multiple motors (one per leg or more) for synchronized movement.

Gearboxes & Wheels: Large-diameter, forged steel wheels with hardened treads.

 

 

3. Power, Control & Motion Systems (The Nerves)

Power Supply System:

Conductor Bar System (Enclosed Track): The most reliable method for heavy-duty, long-travel cranes. Provides continuous power without the maintenance issues of festoon systems.

Operator Control:

Operator's Cab: An insulated, often air-conditioned cabin suspended from the crane bridge, giving the operator a clear view.

Radio Remote Control: Allows the operator to control the crane from the floor for optimal visibility and safety.

Control Panels & Drives:

Main Control Panel: Houses the programmable logic controller (PLC), contactors, overload relays, and Variable Frequency Drives (VFDs). VFDs are crucial for providing smooth, controlled acceleration and deceleration.

4. Critical Safety Systems (The Lifeline)

Load Moment Indicator (LMI): A mandatory system that monitors the load weight and prevents the crane from being overloaded.

Redundant Braking Systems:

Primary Hoist Brake: A high-capacity disc or caliper brake.

Secondary (Emergency) Brake: A fully independent backup brake.

Limit Switches: Heavy-duty limit switches for hoist upper/lower limits, trolley travel, and gantry travel to prevent over-travel.

 

 

Anti-Collision System: Uses sensors to detect and prevent collisions with other cranes on the same runway or obstacles.

Anemometer: Wind speed indicator for outdoor cranes.

Rail Clamps / Anchors: Large mechanical clamps that lock the crane to the rails to prevent movement during storms or when parked.

Buffers & End Stops: Physical bumpers at the ends of the crane and trolley travel to absorb impact.

Summary: Key Differentiators from Lighter Cranes

Component	MH Type (Heavy Duty)	Lighter Duty Cranes
Girders	Double Box Girders	Single Girder or Lighter Double
Hoist	Multiple, Severe-Duty	Single, Standard Duty
Legs	Reinforced & Braced	Simple Rigid Legs
Power Supply	Robust Conductor Bar	Festoon or Simple Cable
Safety	LMI & Redundant Brakes	Basic Limit Switches

Conclusion: Every component of an MH Type Double Beam Gantry Crane is over-engineered for capacity, precision, and reliability. The integration of a robust double-girder structure, powerful and redundant hoists, and comprehensive safety systems makes it a cornerstone asset for heavy industrial material handling.

SKETCH

 

Main technical

 

Advantages of MH Type Double Beam Gantry Cranes

These cranes are engineered for heavy-duty performance, offering a compelling set of benefits for industrial applications.

 

1. Superior Strength and Stability

High Load Capacity: Designed to handle loads from 5 tons to over 550 tons with ease.

Long Span Capability: The double girder design provides exceptional rigidity, allowing for spans of 35 meters and more without significant deflection.

Stable Operation: The robust structure, often with A-frame or braced legs, prevents sway and ensures stable movement even with off-center loads.

2. Maximized Hook Height

Top-Running Trolley: Unlike single girder cranes, the trolley runs on top of the girders. This design provides the maximum possible lifting height between the hook and the ground, which is critical for stacking, handling tall loads, or operating in facilities with high ceilings.

3. Heavy-Duty Durability and Longevity

Built for Intensive Use: Classified for M5 (Heavy Duty) or M6 (Severe Duty) service, meaning they are designed for frequent operation with loads near capacity.

Robust Components: Every part, from the hoist motors to the gears and wheels, is built to withstand high-cycle, demanding environments, resulting in a long service life and reduced downtime.

4. Operational Versatility

Dual Hoist System: Many MH cranes are equipped with both a main hoist for heavy lifts and a faster auxiliary hoist for lighter loads, increasing operational flexibility.

Multiple Attachments: Can be fitted with various lifting devices such as hooks, magnets, grabs, or spreader beams to handle diverse materials like steel coils, containers, scrap, and machinery.

5. Enhanced Safety and Control

Precision Control: Equipped with Variable Frequency Drives (VFDs) for smooth, jerk-free acceleration and deceleration, allowing for precise load positioning.

Integrated Safety Systems: Features like Load Moment Indicators (LMI), redundant braking systems, and limit switches prevent overloads and operational errors, protecting both personnel and assets.

 

Applications of MH Type Double Beam Gantry Cranes

The MH crane's combination of strength, height, and durability makes it indispensable across heavy industries.

 

1. Steel and Metal Industry

Steel Service Centers: Handling and stacking steel coils, plates, sheets, and structural beams (I-beams, channels).

Metal Fabrication Shops: Moving large weldments, raw materials, and finished machinery.

Scrap Yards: Equipped with a magnet for moving and loading ferrous scrap.

2. Power Generation and Heavy Machinery

Power Plants: For maintenance tasks like lifting turbines, transformers, and generators.

Heavy Equipment Manufacturing: Assembling large mining equipment, agricultural machinery, and industrial presses.

3. Logistics and Intermodal Yards

Shipping Ports and Container Yards: Moving shipping containers and heavy cargo. While larger than RTGs, they are used in specific terminal configurations for precise stacking and transfer.

Heavy Logistics Warehouses: Handling oversized and heavy palletized goods that exceed the capacity of forklifts.

4. Construction Materials and Precast Yards

Precast Concrete Plants: Lifting and moving large concrete beams, columns, and wall panels.

Lumber and Building Material Yards: Handling large packs of lumber, building supplies, and other heavy materials.

5. General Heavy Manufacturing and Maintenance

Large-scale Assembly Lines: Moving sub-assemblies between workstations.

Maintenance Bays: Lifting large vehicles, industrial boilers, or other heavy components for repair.

 

The production process for an MH Type Double Beam Gantry Crane is a meticulous sequence of engineering, heavy fabrication, precision assembly, and rigorous testing. It transforms raw steel and high-quality components into a robust, reliable machine built for severe-duty cycles.

Here is a detailed breakdown of the production process.

 

Stage 1: Design & Engineering

This is the foundational stage where the crane is conceived and specified.

Customer Requirements Analysis: Reviewing capacity, span, lifting height, duty cycle (M5/M6), runway details, and operational needs (e.g., magnet, auxiliary hoist).

Conceptual & Detailed Design:

Structural Analysis: Using Finite Element Analysis (FEA) to model the double girders and end trucks for stress, deflection, and fatigue under full load and dynamic conditions.

Mechanical Design: Selecting and designing the hoist units, trolley, travel drives, wheels, and shafts to meet the heavy-duty specifications.

Electrical Design: Creating schematics for power supply, motor controls (VFDs are standard), safety circuits, and operator interfaces (cab or radio remote).

Bill of Materials (BOM) Creation: A complete list of all raw materials (steel plates, profiles) and purchased components (motors, brakes, wire rope, VFDs, bearings).

 

Stage 2: Material Procurement & Preparation

Procurement: Sourcing certified raw materials from steel mills and purchased components from reputable suppliers (e.g., Siemens, SEW, Demag for critical parts).

Material Preparation: Steel plates are shot-blasted to remove mill scale and primed for corrosion protection. They are then cut to size using CNC plasma or flame cutting machines for high precision.

 

Stage 3: Structural Fabrication & Assembly

This is the core of the manufacturing process, where the crane's backbone is built.

Girder Fabrication:

CNC Cutting: Web and flange plates are cut to profile.

Sub-Assembly: Components are fit together in large jigs to ensure straightness and correct geometry.

Welding: Automated Submerged Arc Welding (SAW) is used for the long, critical welds on the main girders to ensure deep penetration and high strength. All welders are certified, and welds may be inspected via ultrasound or X-ray.

Stress Relieving: The completed girders are heated in a large furnace to relieve internal stresses from welding, preventing future distortion and ensuring dimensional stability.

Machining: The girder ends and the surfaces where the trolley rails will be mounted are machined to ensure a perfect fit with the end trucks and smooth trolley travel.

End Truck Fabrication: A similar process of cutting, welding, stress relieving, and machining is used to create the rigid leg structures.

 

Stage 4: Mechanical Assembly

Bridge Assembly: The two main girders are bolted or welded to the end trucks to form the complete bridge structure. Alignment is critical at this stage.

Trolley Assembly: The trolley frame is built, and the main and auxiliary hoist units are mounted onto it. The hoist drums, gearboxes, and motors are aligned with precision to ensure smooth operation and long life.

Drive Unit Installation: The long travel drive assemblies (motor, gearbox, wheel) are installed onto the end trucks. The trolley travel drive is installed on the trolley frame.

Rail Installation: The crane rails for the trolley are installed and aligned on top of the main girders.

 

Stage 5: Electrical & Control System Installation

Panel Building: Main control panels, housing VFDs, programmable logic controllers (PLCs), and protective devices, are assembled and tested.

Crane Wiring: The panels, conductor bar system, and all motors, sensors, and safety devices are wired together on the crane structure. Wiring is done in protective conduits or cable trays.

Safety Devices: All limit switches, the Load Moment Indicator (LMI) system, and emergency stop buttons are installed and wired.

Operator Control: The operator's cab is installed and wired, or the radio remote control system is configured and tested.

 

Stage 6: Works Testing & Inspection (FAT - Factory Acceptance Test)

Before disassembly for shipment, the fully assembled crane undergoes rigorous testing in the factory, often with the client present.

Visual & Dimensional Inspection: Checking for workmanship, paint quality, and verifying all critical dimensions (span, wheelbase).

No-Load Test: Running all motions (hoist, trolley, bridge) without a load to check for smooth operation, abnormal noise, and proper alignment.

Load Testing:

Static Load Test: Lifting a test load of 125% of the rated capacity and holding it to check for structural integrity and brake holding capacity.

Dynamic Load Test: Lifting a test load of 110% of the rated capacity and running it through all motions to verify performance under real-world conditions.

Safety Function Test: Verifying the operation of all limit switches, brakes, E-stops, and the LMI system.

 

Stage 7: Dismantling, Painting & Packaging

Dismantling: The crane is carefully disassembled into transportable pieces (girders, end trucks, trolley, etc.), with all components and connection points clearly marked.

Final Painting: A final coat of high-visibility, weather-resistant paint is applied, often in the customer's specified color.

Packaging: Components are packaged with protective covers on machined surfaces and electrical components to prevent damage during transit.

 

Stage 8: Site Installation & Commissioning (SAT - Site Acceptance Test)

Site Preparation: The manufacturer verifies the customer's runway is complete, level, and correctly aligned.

Erection: Using mobile cranes, the manufacturer's crew reassembles the crane on the customer's runway.

Final Connections: Connecting electrical power, finalizing wiring, and checking alignments.

Site Commissioning & SAT: Repeating key functional and safety tests with the customer present to ensure the crane performs perfectly in its final location. Operator and maintenance training is also provided.

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%.