Qd Type Double Girder Overhead Crane

Key Features of QD-Type Double Girder Overhead Crane

1. Structural Design

Double Box Girders – Heavy-duty welded steel construction for higher load capacity (5-550 tons).

End Carriages – Reinforced steel frames with high-strength wheels for smooth travel.

Runway System – Runs on steel rails or I-beams (indoor/outdoor use).

2. Hoisting Mechanism

Main Hoist + Auxiliary Hoist (Optional) – Allows dual lifting operations.

Main Hoist: Higher capacity (e.g., 50 tons).

Auxiliary Hoist: Lighter loads (e.g., 10 tons).

Wire Rope Hoist (Chinese Standard) – Reliable but less refined than European hoists.

3. Drive & Control System

Travel Motors – For bridge and trolley movement.

Pendant Control / Cabin Operation – Basic controls (upgradeable to radio remote).

Optional VFD (Variable Frequency Drive) – Smoother acceleration/deceleration.

4. Safety Features

Overload Limiter – Prevents lifting beyond capacity.

Limit Switches – For hoisting and travel limits.

Emergency Stop – Immediate shutdown in case of danger.

 

QD-Type vs. European Double Girder Cranes

Feature	QD-Type (Chinese Standard)	European Double Girder (FEM/DIN)
Capacity	5-550+ tons	5-500+ tons
Hoist Quality	Standard wire rope hoist	Premium (Demag, Konecranes)
Control Precision	Basic (upgradable with VFD)	High (standard VFD, smoother operation)
Safety Compliance	GB/T (Chinese standards)	FEM, DIN, EN (strict EU norms)
Price	Lower cost	Higher cost
Lifespan	15-25 years (with maintenance)	25-40+ years

 

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

1. Main Load-Bearing Structure

Double Box Girders

Primary load-bearing beams made of welded steel sections

Designed with reinforced diaphragms for rigidity (typically 5-40m span)

Painted with anti-corrosion coatings (standard: ISO 12944 C4 protection)

End Carriages

Steel fabricated frames with integrated drive systems

Equipped with 4 or 8 wheels (forged steel wheels standard)

Includes buffer assemblies at both ends

2. Hoisting Mechanism

Main Hoist Unit

Wire rope hoist with drum mechanism (standard 6x36 IWRC wire rope)

15-1000kW motor (depending on capacity)

Planetary gearbox with 3-stage reduction

Dual braking system (electromagnetic brake + mechanical backup)

Auxiliary Hoist (Optional)

Typically 20-30% of main hoist capacity

Independent trolley or combined with main hoist

Trolley Assembly

Cross-travel motor (5.5-22kW)

Spur gear transmission system

Steel rail running surface with hardened contact patches

3. Motion System

Bridge Drive System

Dual-motor drive (7.5-45kW motors)

Hardened gear coupling transmission

Frequency-controlled acceleration (0.2-0.5 m/s²)

Running Wheels

Forged steel wheels with double-flange design

Wheel diameter: 400-900mm (capacity-dependent)

Optional polyurethane tread for noise reduction

4. Electrical Systems

Power Supply

Festoon system (standard) or conductor bars (for heavy duty)

IP54 protected cable reels available

Control System

Pendant control station (IP65 rated)

PLC-based protection system

Optional: Radio remote control (2.4GHz FHSS)

5. Safety Components

Load Monitoring

Digital load limiter (Class III accuracy)

Overload cut-off at 110% rated capacity

Position Limiting

Rotary encoder for height control

Magnetic proximity switches for travel limits

Emergency Systems

Red mushroom emergency stop

Anti-collision system (optional laser detection)

.

6. Optional Add-ons

Crane Cab

ISO-certified operator cabin with HVAC

360° visibility design

Special Environments

Heat-resistant modifications (up to 60°C)

Explosion-proof components (ATEX certification)

Automation Features

RFID positioning system

Automatic load sway control

Technical Specifications Table

Component	Standard Spec	Optional Upgrade
Girder Material	Q235B Steel	Q345B High-strength
Hoist Speed	0.5-8 m/min (varies by capacity)	Variable frequency control
Wheel Load	10-400 kN per wheel	Forged alloy steel
Control Voltage	380V 50Hz	480V 60Hz available
Protection Class	IP54	IP65 for harsh environments

Sketch

Main technical

 

 

Heavy-Duty Performance

Capacity range: 5-550 tons (extendable to 800+ tons with custom designs)

Designed for A5-A7 (M5-M8) duty classification (heavy to continuous use)

Robust box girder construction withstands rigorous industrial demands

Superior Structural Integrity

Double girder design provides better load distribution than single girder

Higher hook height (20-30% more than equivalent single girder)

Minimal deflection (<1/800 of span at rated load)

Enhanced Safety Features

Dual braking systems (electrical + mechanical)

Redundant load-limiting devices (mechanical + electronic)

Emergency power-off system with backup power option

Operational Flexibility

Optional dual-hoist configuration (main + auxiliary)

Multiple control modes (pendant/cabin/remote/automated)

Customizable speeds (hoisting: 0.5-20 m/min; travel: 5-40 m/min)

Economic Benefits

30-50% lower initial cost than European equivalents

Simplified maintenance with modular components

Energy-efficient VFD options reduce power consumption by 15-25%

Adaptability

Special variants available for:

High-temperature environments (up to 60°C)

Corrosive atmospheres (marine-grade protection)

Explosion-proof applications (Ex d/e certification)

 

1. Heavy Manufacturing

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

Foundries: Moving casting molds and finished products

Heavy machinery plants: Assembling large components

2. Energy Sector

Power plants: Turbine installation/maintenance (100-500t)

Hydroelectric facilities: Generator handling

Nuclear facilities: Shielded material handling

3. Logistics & Transportation

Port terminals: Container handling (30-50t)

Railway yards: Locomotive maintenance

Shipbuilding: Section assembly (100-800t)

4. Mining & Minerals

Mineral processing plants

Bulk material handling (coal, ores)

Crusher and mill maintenance

5. Specialized Applications

Aerospace: Large component assembly

Bridge construction: Precast segment installation

Waste management: Scrap handling magnets

1. Design and Engineering
Confirm technical specifications (load capacity, span, lifting height).

Structural design of main beams, end carriages, trolley, and hoisting system using CAD and FEA software.

Electrical and control system layout design.

Compliance checks with relevant standards (ISO, FEM, OSHA).

2. Material Procurement
Source high-quality steel plates, structural steel sections, motors, electrical components, limit switches, and safety devices.

Verify material certifications and quality standards.

3. Fabrication of Main Components
Cutting & Shaping: Use CNC plasma cutting or laser cutting for steel plates.

Welding: Assemble main beams, end carriages, trolley frames using precise welding techniques.

Heat Treatment: Stress relief welding distortion by heat treatment if required.

Machining: Machine wheel seats, bearing seats, shaft holes, and motor mounting points.

Surface Treatment: Sandblasting and applying primer, then coating with anti-corrosion paint.

4. Assembly of Mechanical Parts
Assemble main beams with end carriages.

Install wheelsets and axle assemblies.

Mount trolley frame and hoisting mechanism (drum, wire rope, hook block).

Install brakes and gearbox on motors.

5. Electrical System Installation
Install motors (hoist, trolley, bridge travel).

Mount electrical panels, control cabinets.

Wire all sensors, limit switches, alarms, and control devices.

Connect power cables and control cables.

6. Quality Control & Testing
Non-destructive testing (NDT): Weld inspections by ultrasonic or magnetic particle methods.

Dimensional inspection: Check critical dimensions and tolerances.

Electrical tests: Insulation resistance, continuity, and control circuit tests.

Load testing: Perform static and dynamic load tests at 100% and 125% rated load.

Functional testing: Test all crane movements, alarms, safety devices, and control systems.

7. Painting and Finishing
Final painting for corrosion resistance and aesthetics.

Apply safety markings and labels.

8. Packaging and Delivery
Disassemble components if needed for transport.

Secure packaging to avoid damage during shipment.

Prepare manuals, certificates, and test reports.

9. Installation and Commissioning (On-site)
Assemble crane components on-site.

Align rails and fix end stops.

Connect power supply and control system.

Conduct on-site testing and operator training.

Final acceptance and handover.

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%.