Double Girder Overhead Crane With Hook

Why Choose a Double Girder Overhead Crane?

✔ Higher load capacity (handles 20T to 500T+).
✔ Longer spans (up to 50m or more).
✔ Better hook height (more lifting clearance).
✔ Greater durability for harsh industrial environments.
✔ Smoother operation with advanced controls (VFD, automation).

 

Key Features & Components

1. Structural Design

Two main girders (box-type or truss design) for increased strength.

Top-running hoist system (runs on rails mounted on top of girders).

Higher hook height (more lifting clearance than single girder cranes).

2. Hoist & Hook Mechanism

Wire rope hoist (common for heavy loads, e.g., 20T to 500T+).

Hook block assembly (swiveling or fixed, depending on precision needs).

Optional: Dual-hook system for tandem lifting.

3. Drive & Control System

Travel motors (for bridge movement along runway rails).

Trolley drive (for cross-travel along girders).

Pendant control / Radio remote / Cabin-operated.

Variable Frequency Drive (VFD) for smooth acceleration & positioning.

4. Runway & Support Structure

Heavy-duty runway beams (typically reinforced I-beams or fabricated tracks).

End trucks with double-wheel design for better load distribution.

5. Safety Features

✔ Overload protection (cuts power if capacity is exceeded).
✔ Limit switches (prevents over-travel).
✔ Emergency stop button.
✔ Anti-collision system (for multiple cranes in same bay).

 

Advantages Over Single Girder Cranes

Feature	Double Girder Crane	Single Girder Crane
Lifting Capacity	20T to 500T+	Up to 20T (typically)
Span Length	Up to 50m+	Up to 30m
Hook Height	Higher (top-running hoist)	Lower (underhung hoist)
Durability	Heavy-duty, long lifespan	Moderate-duty
Precision	Better for high-precision lifts	Suitable for general use
Maintenance	More components but built for heavy cycling	Simpler, lower maintenance

 

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's a detailed technical specification of all major components in a double girder overhead crane system with hook:

1. Bridge Structure

Main Girders (2x)

Fabricated from high-grade steel (Q235B/Q345B)

Box-type construction (welded steel plates)

Typical span: 10-35m (customizable up to 50m+)

Includes walkways and maintenance platforms

End Trucks

Heavy-duty welded steel construction

Dual-wheel configuration (4 or 8 wheels total)

Wheel diameter: 400-800mm (based on load)

Includes buffer assemblies and anti-derailment devices

2. Hoisting Mechanism

Electric Wire Rope Hoist

Capacity range: 5-500T

Rope diameter: 8-32mm (dependent on load)

Drum diameter: 400-2000mm

Lifting speed: 0.5-8m/min (variable frequency controlled)

Hook Assembly

Forged steel hook (Grade 80 or 100)

Swivel-type or fixed design

Safety latch included

Load rating clearly marked

3. Trolley System

Trolley Frame

Steel plate welded construction

Includes guide rollers for smooth travel

Equipped with anti-sway mechanisms

Travel Drive

Dual-motor drive system

Gearbox ratio: 1:31.5 to 1:50

Wheel diameter: 250-500mm

Speed: 20-40m/min (VFD adjustable)

4. Crane Travel Mechanism

Drive Units

2 or 4 driving wheels

AC 3-phase induction motors (7.5-75kW)

Brake motors with thermal protection

Rail System

QU80/QU100/QU120 steel rails

Rail clamp assemblies

Fishplate connections for long spans

 

5. Electrical Systems

Power Supply

Sliding conductor system (safe rail or festoon)

380V/415V, 50Hz, 3-phase

IP54 protection grade

Control System

Pendant control station (24V/36V safety voltage)

Optional radio remote control (2.4GHz)

PLC-based smart control available

Safety Devices

Overload limiter (95-110% adjustable)

Limit switches (rotary and collision types)

Emergency stop buttons

Phase failure protection

6. Auxiliary Components

Ladders & Platforms

Maintenance access ladders

Operator cabin platform (when equipped)

Anti-slip grating surfaces

Lighting System

LED work area lighting

Emergency lighting provisions

Lubrication System

Centralized automatic lubrication

Manual grease points

7. Optional Add-ons

Weighing System

Digital load indicator

1% FS accuracy

Anti-Sway System

PLC-controlled sway prevention

Camera monitoring

Automation Packages

Position control system

Automated routing

Technical Specifications Table

Component	Specification Range	Material/Type
Main Girder	Span 10-50m	Q345B Steel
Hoist Capacity	5-500T	Wire Rope
Hook	1-500T	Alloy Steel
Travel Speed	20-40m/min	VFD Controlled
Working Class	A5-A7	FEM Standard
Power Supply	380V/50Hz/3P	IP54

Sketch

Main technical

 

 

1. Superior Load Capacity

Handles 5-500+ tons (vs. single girder's typical 20T max)

Heavy-duty construction for continuous industrial use

Higher safety factor in load-bearing structure

2. Increased Span Capability

10-50m spans without intermediate support

Better stability for long-span applications

Reduced deflection under full load

3. Greater Hook Height

Top-running design provides maximum lift height

No lost space from underhung hoists

Critical for facilities with tall components

4. Enhanced Durability

Robust box girder construction

Longer service life in harsh environments

Reduced maintenance despite heavy use

5. Precision Handling

Smooth VFD control for exact positioning

Anti-sway systems available

Better load control for delicate operations

6. Customization Options

Modular designs for specific needs

Multiple hook configurations

Automation-ready for smart factories

7. Safety Features

Redundant braking systems

Advanced overload protection

Comprehensive limit switches

 

1. Heavy Manufacturing

Steel mills: Handling coils, slabs (100T+)

Foundries: Moving castings and molds

Press shops: Transferring large stampings

2. Energy Sector

Power plants: Turbine maintenance

Wind energy: Nacelle assembly

Nuclear facilities: Safe handling of heavy components

3. Transportation Equipment

Shipyards: Engine block positioning

Rail: Bogie and chassis handling

Aerospace: Large component assembly

4. Infrastructure Projects

Bridge construction: Precast segment handling

Dam construction: Heavy machinery movement

Tunnel boring: Segment ring installation

5. Specialized Material Handling

Paper mills: Roll handling (50T+)

Mining: Equipment maintenance

Chemical plants: Reactor vessel installation

 

The production procedure for a 45-ton Double Girder Overhead Crane involves several key stages, from design to final testing. Below is a detailed step-by-step overview:

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1. Design & Engineering

Load & Span Calculation: Determine crane capacity (45 tons), span (distance between rails), lifting height, and duty cycle (FEM/ISO classification).

Structural Design:

Main girders (box-type or truss design)

End carriages (for movement along rails)

Hoist and trolley mechanism

Electrical & Mechanical Design:

Motor power, gearbox, brakes, and control system

Wiring, pendant/radio remote control, or cabin operation

Software & Simulation: Finite Element Analysis (FEA) for stress testing.

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2. Material Procurement

Steel Plates & Profiles: High-quality Q235B/Q345B steel for girders.

Electrical Components: Motors (hoist/travel), brakes, limit switches, and control panels.

Mechanical Parts: Wheels, gears, wire ropes, hooks, and bearings.

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3. Fabrication of Main Components

A. Double Girder Fabrication

Cutting & Welding: CNC plasma cutting for precision; automatic submerged arc welding (SAW) for girders.

Assembly: Align and weld girders with end carriages.

Shot Blasting & Painting: Anti-rust treatment (primer + topcoat).

B. Hoist & Trolley Assembly

Hoist Mechanism:

45-ton electric wire rope hoist (or chain hoist).

Drum, motor, gearbox, and brake assembly.

Trolley Frame: Fabrication and mounting of wheels, motors, and rails.

C. End Carriages

Frame Construction: Welded steel with wheel assemblies.

Buffers & Bumpers: Installation for collision protection.

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4. Electrical System Installation

Wiring & Controls:

Power supply (3-phase AC)

Variable Frequency Drives (VFDs) for smooth operation

Pendant/remote control system

Safety Devices:

Overload limiter

Limit switches (upper/lower travel)

Emergency stop

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5. Assembly & Integration

Erection of Girders: Mount double girders onto end carriages.

Trolley & Hoist Installation: Position trolley between girders; secure hoist.

Rail Alignment: Ensure runway rails are level and parallel.

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6. Testing & Quality Control

A. Factory Testing (Before Shipment)

No-Load Test: Run crane without load to check movement, brakes, and controls.

Load Test:

Static Test: 1.25 × rated load (56.25 tons) for 10 mins.

Dynamic Test: 1.1 × rated load (49.5 tons) with movements.

Safety Checks: Verify limit switches, emergency stop, and overload protection.

B. On-Site Testing (After Installation)

Re-run load tests under customer supervision.

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7. Painting & Corrosion Protection

Final Coating: Weather-resistant paint (e.g., epoxy zinc-rich primer).

Markings: Labels for load capacity, warnings, and manufacturer info.

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8. Packaging & Delivery

Disassembly (if needed): For easy transport.

Packaging: Waterproof wrapping for sea/land shipping.

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9. Installation & Commissioning (On-Site)

Runway Beam Inspection: Ensure proper alignment and strength.

Crane Assembly: Reassemble girders, hoist, and electrical systems.

Final Testing: Conduct load tests and operator training.

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%.