QC Electric Double Girder Overhead Crane

Key Features of QC Electric Double Girder Overhead Crane

1. Robust Construction

Double girder design for higher load capacity (typically 5 to 550 tons).

Heavy-duty steel fabrication (Grade Q235B/Q345B) for long-term durability.

Welded & stress-relieved girders to prevent deformation.

2. High-Performance Electric Winch/Hoist

European-style or American-style hoist (depending on application).

Variable speed control (dual-speed or inverter-controlled for smooth operation).

Fail-safe braking system (electromagnetic + mechanical brakes).

3. Precision Movement & Control

Travel drives with sealed gearboxes for smooth bridge and trolley movement.

Anti-sway technology (optional) for precise load positioning.

Radio remote control / pendant control for safe and flexible operation.

4. Enhanced Safety Features

Overload limit switch (prevents lifting beyond capacity).

Upper/lower limit switches (automatic cut-off at maximum height).

Emergency stop (E-stop) button for instant shutdown.

Crane runway end buffers to absorb impact.

Advantages Over Single Girder Cranes

Feature	Double Girder Crane	Single Girder Crane
Load Capacity	Up to 550+ tons	Up to 20 tons
Span Length	Longer spans (up to 35m+)	Shorter spans
Lifting Height	Higher (no space lost to hoist above girder)	Lower (hoist hangs below girder)
Durability	More robust for heavy-duty cycles	Lighter-duty use
Precision	Better for high-precision tasks	Suitable for basic lifting

 

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

 

 

This professional-grade overhead crane consists of carefully engineered components that work together to provide safe, reliable heavy lifting performance. Here's a comprehensive breakdown:

1. Bridge Structure

Main girders (2) - Fabricated from high-grade steel (Q345B) with optimized I-beam or box-type design

End trucks - Heavy-duty assemblies with:

Driven wheels (for powered movement)

Idler wheels (for smooth travel)

Anti-derailment devices

Connection beams - Ensure parallel movement of both girders

2. Hoisting System

Electric wire rope hoist (standard):

Gear-motor unit with thermal protection

Drum with precision grooving

Wire rope (rotation-resistant, ISO 2408 compliant)

Hook block with safety latch

Overload limiter (mechanical or electronic)

Alternative options:

Chain hoist for lighter duty

Explosion-proof hoist for hazardous areas

 

 

3. Trolley Assembly

Frame construction - Steel welded structure

Drive mechanism:

Trolley travel motors (dual-motor for synchronization)

Gearboxes with forced lubrication

Rail wheels with hardened treads

Guiding system - Lateral rollers for smooth tracking

4. Runway System

Runway beams - Fabricated or rolled sections

Crane rails (typically QU80/QU100):

Properly aligned and leveled

Rail clamps for secure fastening

Rail joints ground smooth

Runway conductors:

Festoon system for power supply

Or conductor bars for heavy current

5. Electrical System

Power supply:

Main line contactor

Emergency stop circuit

Phase sequence protection

Control system:

Pendant control station (IP65 rated)

Or wireless remote control (2.4GHz)

Variable frequency drives (for premium models)

Safety devices:

Limit switches (travel and hoisting)

Anti-collision system (for multiple cranes)

Voltage protection

6. Safety Components

Buffers and bumpers - Hydraulic or spring type

Anemometer (for outdoor cranes)

Warning devices:

Beacon lights

Alarm buzzer

Emergency escape ladder (for cab-operated cranes)

.

7. Optional Components

Weighing system - Load cells with digital display

Automation package:

Programmable logic controller

Position sensors

Automated positioning system

Special coatings:

High-temperature paint

Corrosion-resistant finish

Cabin - Ergonomically designed operator station

8. Structural Reinforcements

Diagonal bracing - For increased rigidity

Stiffener plates - At high-stress points

Seismic restraints - For earthquake-prone areas

Each component undergoes rigorous QC testing including:

Dimensional verification

Non-destructive testing (UT, MPI)

Load testing (125% of SWL)

Electrical safety tests

Functional operation tests

The complete system is designed for:

Minimum 10-year structural life

Class A5-A8 duty cycle (FEM standard)

24/7 operation capability in industrial environments

 

12.Sketch

Main technical

 

 

Superior Load Capacity

Handles 5-550+ tons (vs. single girder's 1-20 ton limit)

Ideal for heavy industrial applications like steel mills and power plants

Enhanced Structural Rigidity

Twin girders provide greater stability for precision handling

Minimizes deflection under heavy loads (≤1/800 of span length)

Higher Lifting Height

Hoist mounted between girders (vs. below single girder)

Gains additional 1-2m hook height - crucial for tall workshops

Advanced Safety Features

Dual braking systems (electromagnetic + mechanical)

Fail-safe overload protection (mechanical + electronic)

IP54/55 rated components for dust/water resistance

Precision Movement Control

Variable frequency drives enable 0.2m/min creep speed

Anti-sway systems achieve ±10mm positioning accuracy

Extended Service Life

FEM A6-A8 duty classification (up to 600,000 cycles)

Hardened rail wheels (HRC50+) for reduced wear

Smart Operation Options

Remote monitoring via IoT sensors

Automated positioning with laser guidance

Customization Flexibility

Modular design allows for:

Explosion-proof variants (ATEX certification)

High-temperature versions (up to 60°C ambient)

Corrosion-resistant coatings (C5-M marine grade)

 

 

1. Heavy Manufacturing

Steel mills: Handling coils (up to 40t), slabs, and molten metal

Automotive: Moving press dies (50-300t) with precision

2. Energy Sector

Power plants: Installing turbine rotors (200-400t)

Nuclear facilities: Remote-controlled fuel rod handling

3. Infrastructure Projects

Precast concrete: Positioning bridge segments (80-150t)

Shipbuilding: Turning ship blocks (100-500t)

4. Mining & Minerals

Processing plants: Lifting crushers (75-200t)

Smelters: Charging furnaces with 50t ladles

5. Specialized Applications

Aerospace: Clean room component handling

Ports: Grab bucket operations for bulk materials

 

 

1. Design and Engineering
Initial Consultation: The process begins with understanding the specific requirements of the customer, including lifting capacity, span, lifting height, and operational environment. This helps in customizing the crane to meet the exact needs.

Detailed Engineering Design: The engineering team designs the crane based on the customer's specifications. This includes the structural design of the main beam, trolley, hoist, end carriages, and control systems. Calculations for load-bearing capacities, safety factors, and the integration of components are also done during this phase.

CAD Modeling: A Computer-Aided Design (CAD) model of the crane is created to visualize and test the design. The model is reviewed for any potential issues in terms of load distribution, operation, and stability.

2. Material Selection
Raw Material Procurement: High-quality materials such as steel plates, beams, and components for the main girder, hoist, trolley system, and other parts are sourced. The materials must meet industry standards for strength, durability, and resistance to wear.

Material Inspection: All materials are inspected to ensure they meet the required quality standards. This includes checking for any defects, such as cracks, rust, or deformation.

3. Fabrication and Manufacturing
Girder Fabrication:

Cutting and Shaping: Steel plates and sections are cut to the required dimensions based on the design specifications. The steel is then shaped into beams and girders using various methods such as welding and bending.

Welding: The individual pieces of the main girder and cross beams are welded together. The welding is performed according to strict quality standards to ensure the structural integrity of the crane.

Stress Relieving: After welding, the steel is heat-treated (stress-relieved) to eliminate any residual stresses from the welding process.

End Carriages and Trolley Fabrication:

The end carriages are fabricated, including wheel assemblies, frames, and supporting structures.

The trolley is assembled, including the hoist mechanism and the travel mechanism, such as wheels or rollers, which allow the trolley to move along the bridge.

Wheel Assembly: The crane wheels are manufactured and installed on the end carriages, ensuring that they are aligned and balanced for smooth movement along the bridge.

4. Hoisting Mechanism Production
Motor and Gearbox Assembly: The hoisting motor, gearbox, and other drive components are assembled. These are selected based on the required lifting capacity and speed.

Hoist Drum and Wire Rope: The hoist drum is manufactured and fitted with the wire rope that will be used to lift and lower the load. The wire rope is carefully selected for strength and durability.

Hoist Installation: The hoisting system, including the motor, gearbox, drum, and wire rope, is integrated into the trolley.

5. Crane Assembly
Main Girder Assembly: The fabricated main girder is placed on a flat surface, and the end carriages are attached to each end of the girder. The crane is then set up to be able to travel across the rails.

Trolley and Hoist Integration: The trolley is mounted on the main girder. It is designed to move horizontally along the girder, carrying the hoist and hook. The trolley's wheels are adjusted to ensure smooth operation.

Electrical Wiring and Control System: Electrical components such as motors, control panels, limit switches, and alarm systems are installed. The control system is connected, allowing the crane to be operated remotely or manually. This may include pendant controls, radio remote controls, or cabin controls, depending on the design.

Safety Devices Integration: Safety systems like limit switches, overload sensors, braking systems, and sound and light alarms are installed to ensure safe operation.

6. Testing and Quality Control
Initial Inspection: After assembly, the crane undergoes a series of inspections to ensure that all components are installed correctly and that the crane meets the design specifications.

Load Testing: The crane is subjected to load testing to ensure it can handle the specified lifting capacity without any issues. The load testing is done under controlled conditions, and the crane is observed for proper operation.

Operational Testing: The crane is tested for smooth operation, including movement along the bridge, the function of the trolley, and the hoist. The speed, braking system, and overall functionality are tested to ensure everything is in working order.

Safety Compliance Testing: Safety features, including limit switches, overload protection, and emergency stop mechanisms, are thoroughly tested to meet safety regulations.

Electrical Testing: All electrical components, including wiring, switches, and controls, are tested for proper functioning and compliance with electrical safety standards.

7. Final Adjustments and Calibration
Final Inspection: Once all tests are complete and successful, the crane undergoes a final inspection to ensure all components are properly calibrated and aligned.

Adjustments: If any issues are detected during the testing phase, adjustments are made to the crane, such as recalibrating the control systems or adjusting the alignment of the wheels and track.

8. Packaging and Shipping
Disassembly for Shipping: In many cases, the crane is partially disassembled for shipping to the customer's site. Components such as the hoist, trolley, and control panels are securely packaged.

Shipping: The crane is carefully transported to the client's location via road, rail, or sea, depending on the destination.

Delivery Documentation: Necessary documentation, including user manuals, maintenance guides, and certificates of compliance, are provided to the customer.

9. Installation and Commissioning
On-Site Assembly: Upon arrival at the customer's site, the crane is fully assembled, and final connections are made, including electrical wiring, safety systems, and control systems.

Site Testing: The crane is tested again at the installation site to ensure it operates correctly in its intended environment.

Operator Training: Operators and maintenance staff are trained on how to operate and maintain the crane. This includes safety procedures, control usage, and troubleshooting techniques.

Final Handover: After successful installation and testing, the crane is officially handed over to the customer for operation.

10. Post-Installation Support
Ongoing Maintenance and Support: The crane manufacturer provides post-installation support, which includes regular maintenance, spare parts, and technical assistance when needed.

Warranty and Service: A warranty period is usually provided, during which any defects or issues are resolved free of charge.

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%.