EOT Double Girder Overhead Crane

What is an EOT Double Girder Overhead Crane?

An EOT Double Girder Overhead Crane (Electric Overhead Traveling Crane) is a heavy-duty industrial crane where the main bridge consists of two girders supported by end trucks that travel along runway beams. The hoist and trolley operate on top of the two girders, making it the most common configuration for high-capacity, intensive-duty applications.

 

Advantages

High Lifting Capacity: Suitable for capacities from 5 tons up to 500+ tons.

Maximum Hook Height: The top-running trolley utilizes the full height of the building, providing more clearance under the hook.

Exceptional Rigidity and Stability: The double girder structure is very rigid, minimizing deflection and ensuring smooth, precise load control.

Durability for Severe Duty: Built for high-cycle, intensive use in environments like steel mills, fabrication shops, and heavy machine shops (typically Duty Class M5/M6).

Versatility: Can be equipped with various attachments like magnets, grabs, or special hooks.

 

Common Configurations

Top-Running Double Girder: The most common type, where the crane rails are mounted on top of the runway beams.

Under-Running Double Girder: Less common, where the crane wheels run on the bottom flange of the runway beams. Used when support structure is limited.

 

Comparison: EOT Double Girder vs. Single Girder

Feature	EOT Double Girder	Single Girder
Girder Design	Two Girders	Single Girder
Duty Cycle	Heavy/Severe (M5/M6)	Light/Moderate (M3/M4)
Typical Capacity	5 - 500+ Tons	1 - 20 Tons
Hook Height	Maximum	Lower
Cost	Higher	Economical
Ideal For	Heavy, intensive use	Lighter, occasional use

Conclusion: The EOT Double Girder Overhead Crane represents the gold standard for heavy-duty, high-capacity overhead lifting. Its robust double-girder bridge and top-running trolley offer an optimal combination of strength, height, and reliability, making it the preferred choice for the most demanding industrial applications. It is a fundamental piece of infrastructure that drives productivity and safety in heavy industry.

 

Core Components：Bearing, Gearbox, Motor, Pump

Place of Origin：Henan, China

Warranty：1 Year

Weight (KG)：2000 kg

Video outgoing-inspection：Provided

Machinery Test Report：Provided

Design：Double beam

Effectiveness：high efficiency

Operating speed：High speed operation

Stability：Anti-swing function

Color：Optional

Power Source：110V/220V/230V/380V/440V,customized

Span：7.5-31.5m

Here is a detailed breakdown of the components of an EOT Double Girder Overhead Crane.

 

1. Primary Structural System (The Framework)

Double Main Girders: The primary horizontal beams that form the bridge.

Box Girders: Fabricated from steel plate for superior strength and rigidity. Used for heavier capacities and longer spans.

I-beams: Rolled sections, sometimes with added reinforcement plates. Used for medium-duty applications.

End Trucks: The structures at each end of the bridge that house the wheels and drive mechanisms for moving the entire crane along the runway.

Runway System:

Runway Beams: Heavy I-beams or box sections supported by the building columns.

Running Rails: Steel rails mounted on top of the runway beams for the crane to travel on.

Crane Buffers: Shock-absorbing devices at the ends of the runway to stop crane travel.

2. Lifting & Travel System (The Workhorse)

Main Hoist Unit:

Hoist Motor: Electric motor providing lifting power.

Gearbox: Reduces motor speed to increase torque.

Wire Rope Drum: Spools the wire rope.

Brakes: Primary and secondary braking systems.

Trolley Assembly:

Trolley Frame: Supports the hoist unit.

Trolley Wheels & Drive: Wheels that run on rails on top of the main girders, with a separate drive motor for transverse movement.

Auxiliary Hoist: A smaller, faster hoist on the same trolley for lighter loads.

Hook Block: The assembly that holds the hook, often with multiple sheaves for mechanical advantage.

Bridge Travel Drives:

Drive Motors: Motors mounted on the end trucks to propel the entire crane.

Wheels: Flanged wheels that run on the runway rails.

 

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

Power Supply System:

Conductor Bar System: Enclosed power bars running parallel to the runway.

Festoon System: A trolley and track system that carries flexible power cables.

Control Interface:

Pendant Station: A hanging push-button control box.

Radio Remote Control: Wireless operation for operator mobility.

Operator's Cab: For very large cranes, an enclosed cab may be provided.

Control Panel:

Programmable Logic Controller (PLC): The crane's brain.

Contactors and Relays: For power distribution.

Variable Frequency Drives (VFDs): For smooth speed control of all motions.

4. Critical Safety Systems (The Lifeline)

Load Moment Indicator (LMI): Monitors load weight and prevents overloads.

Limit Switches:

Hoist Upper/Lower Limit: Prevents over-hoisting or over-lowering.

Travel Limits: Stops crane and trolley at runway ends.

Braking Systems:

Hoist Brake: Automatically holds the load.

Travel Brakes: On bridge and trolley drive motors.

Anemometer: For outdoor cranes, measures wind speed.

Anti-Collision System: Prevents collisions between multiple cranes.

Emergency Stop Buttons: Located at various points on the crane.

Summary: Key Features of an EOT Double Girder

Component	EOT Double Girder Characteristic
Girders	Two heavy-duty girders for maximum strength
Hoist	Severe-duty rated for intensive use
Trolley	Top-running for maximum hook height
Control	Sophisticated with VFDs for precision
Safety	Comprehensive systems including LMI

Sketch

Main technical

 

 

Advantages of EOT Double Girder Overhead Crane

EOT Double Girder Cranes offer a powerful combination of strength, precision, and reliability for demanding industrial applications.

1. Superior Strength and Load Capacity

High Load Capacity: Designed to handle loads from 5 tons to over 500 tons with ease, making it suitable for the heaviest industrial applications.

Exceptional Rigidity: The double girder design provides superior resistance to bending and torsion, minimizing deflection even under maximum load and long spans.

Stable Operation: The robust structure ensures stable movement, even when handling off-center or swinging loads.

2. Maximum Hook Height

Optimal Vertical Space Use: The top-running trolley design provides the maximum possible hook height, which is critical for stacking, handling tall loads, or operating in facilities with high ceilings.

Clear Floor Space: Like all overhead cranes, it operates above the work area, keeping the floor completely clear for other equipment and activities.

3. Exceptional Durability and Uptime

Built for Severe Service: Rated for M5 (Heavy Duty) or M6 (Severe Duty) cycles, meaning it is engineered for frequent, intensive use, often 24/7.

Long Operational Life: Constructed with premium, industrial-grade components that withstand shock loads and demanding environments, resulting in decades of reliable service with minimal downtime.

4. Precision and Control

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

Multiple Speeds: Often feature multiple hoisting and traveling speeds for both power and precision.

Accurate Spotting: Enables precise placement of high-value loads, reducing the risk of damage and improving production quality.

5. Versatility and Safety

Adaptable to Various Tasks: Can be fitted with a variety of attachments:

C-hooks for steel coils

Magnets for scrap and steel plate

Vacuum Lifters for sheet material

Specialized grabs for unique loads

Enhanced Safety Systems:

Load Moment Indicator (LMI): Prevents dangerous overloads.

Redundant Braking: Multiple independent braking systems.

Limit Switches: Prevents over-travel of all motions.

 

Applications of EOT Double Girder Overhead Crane

The EOT Double Girder Crane is the backbone of industries where heavy, precision lifting is a core function.

1. Steel and Metal Industry

Steel Mills: Handling raw materials (scrap, pig iron), finished coils, slabs, and plates.

Metal Service Centers: Stacking and moving steel coils, plates, and structural beams.

Foundries: Charging scrap metal into furnaces and handling castings.

2. Heavy Machinery and Equipment Manufacturing

Assembly Operations: Moving massive mining truck frames, agricultural equipment, and industrial presses.

Component Handling: Positioning large weldments, engines, and other heavy sub-assemblies.

3. Power Generation

Power Plants: For maintenance of turbines, generators, and transformers.

Dam Construction: Handling large components for hydroelectric power projects.

4. Warehousing and Logistics

Heavy Logistics Warehouses: Handling oversized and heavy palletized goods.

Loading/Unloading: Moving heavy equipment and machinery in and out of storage.

5. Automotive and Aerospace

Automotive Plants: Moving large stamping presses and dies.

Aerospace Facilities: Handling large aircraft components and assemblies.

 

The production process for an EOT Double Girder Overhead Crane is a meticulous, multi-stage procedure that ensures the final product is safe, reliable, and built for heavy-duty service.

Here is a detailed breakdown of the production process.

 

Stage 1: Design & Engineering

This is the foundational stage where the crane's performance and safety are defined.

Client Requirements Analysis: Reviewing key parameters: capacity, span, lifting height, duty cycle (M5/M6), service class, and operational needs (e.g., magnet, special hooks).

Advanced Engineering:

Structural Analysis (FEA): Using Finite Element Analysis to model the girders, end trucks, and connections under dynamic loads to ensure no point is over-stressed.

Mechanical Design: Designing the hoist units, trolley, travel drives, and wheel systems to meet the specified duty class.

Electrical & Control Design: Creating schematics for power supply, motor controls (VFDs), PLC networks, and safety circuits.

Bill of Materials (BOM) Creation: A comprehensive list of all raw materials and purchased components.

 

Stage 2: Material Procurement & Preparation

Procurement: Sourcing certified steel plates, beams, and purchased components (hoists, motors, electrical gear from reputable suppliers).

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

 

Stage 3: Structural Fabrication & Assembly

This is where the crane's robust frame is built.

Girder Fabrication:

Box Girder Construction: For heavy-duty cranes, girders are fabricated from steel plate. Web and flange plates are cut, and internal stiffeners are welded in to prevent buckling.

Process: Components are fit in large jigs to ensure straightness and correct geometry.

Welding: Critical welds are performed using Automated Submerged Arc Welding (SAW) for deep penetration and high quality. All critical welds are inspected by certified welders and may be tested via Ultrasound (UT).

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

Machining: The girder ends and surfaces where the trolley rails will be mounted are machined to ensure perfect alignment.

 

Stage 4: Mechanical Assembly

The structural frame is integrated with the mechanical systems.

End Truck Assembly: The end trucks are built, housing the wheels, axles, and bridge travel drive assemblies.

Bridge Assembly: The two main girders are connected to the end trucks to form the complete bridge structure.

Trolley Assembly: The trolley frame is built, and wheels are attached. The main and auxiliary hoist units are then mounted and aligned onto the trolley frame.

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

 

Stage 5: Electrical & Control System Installation

The crane's control and power systems are installed.

Cable Installation: Power and control cables are run along the crane structure in protective conduits or cable trays.

Panel Installation: Main control panels, housing VFDs, PLCs, contactors, and overload protection, are mounted on the bridge.

Power Supply Setup: Installation of the conductor bar system or festoon system for power delivery along the runway.

Safety Devices: Installing and wiring limit switches, emergency stops, and the Load Moment Indicator (LMI) system.

 

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

The fully assembled crane is tested to ensure it meets all specifications and safety standards.

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

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

Load Testing:

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

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

Safety Function Test: Verifying the operation of all limit switches, brakes, E-stops, and overload protection devices.

 

Stage 7: Dismantling, Painting & Packaging

Dismantling: The crane is carefully disassembled into transportable modules (girders, end trucks, trolley).

Final Painting: A high-performance paint system is applied for corrosion protection.

Packaging: Components are securely packaged, with special attention to protecting machined surfaces and electrical components.

 

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

Site Erection: The crane is reassembled on the customer's runway.

Final Connections: Electrical power is connected, and final checks are made.

Site Commissioning & SAT: The crane undergoes a final operational test in its actual working environment.

Operator Training: The customer's operators are trained on safe and efficient use.

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%.