Qd Double Girder Overhead Crane

 

 

Selection Considerations

Load Capacity & Span – Match to your heaviest loads and workspace dimensions.

Duty Cycle – Choose between A3 (Medium Duty), A4 (Heavy Duty), or A5 (Severe Duty).

Environment – Consider heat, dust, or corrosive conditions.

Power Supply – Typically 3-phase AC, but options include explosion-proof or battery-powered.

 

Comparison: QD Double Girder vs. Single Girder

Feature	Double Girder	Single Girder
Capacity	5–550+ tons	1–20 tons
Span	Up to 35m+	Up to 15m
Hook Height	Higher	Lower
Cost	Higher initial cost	More economical
Durability	Heavy-duty	Light to medium-duty

 

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 breakdown of the key components in a QD (Quality Duty) Double Girder Overhead Crane, along with their functions and technical considerations:

1. Bridge Structure (Main Load-Bearing Frame)
Double Girders

Two heavy-duty steel box girders or truss girders running parallel.

Designed to handle high capacities (typically 5–550+ tons).

End Trucks (End Carriages)

Wheeled assemblies at each end of the girders for longitudinal movement.

Include drive motors, wheels, and buffers (shock absorbers).

2. Hoist & Trolley Assembly
Electric Hoist (or Hydraulic)

Gear-driven motor with wire rope drum or chain mechanism.

Common types: LH (European) or GH (American) hoists.

Trolley Frame

Moves horizontally along the girders via motorized wheels.

Equipped with guide rollers to prevent skewing.

 

 

3. Runway System
Runway Beams

Steel I-beams or box sections mounted on building columns or freestanding supports.

Rail Tracks

Usually QU80/QU100 rails (for heavy loads) or square rails for lighter duty.

Crane Buffers

Rubber or hydraulic bumpers at runway ends to absorb impact.

4. Drive & Motion System
Bridge Drive

Dual-motor system (one per end truck) for synchronized movement.

May include frequency control for smooth acceleration/deceleration.

Trolley Drive

Motorized wheels for transverse movement across girders.

5. Electrical & Control System
Power Supply

Festoon system (cable reels) or conductor bars (busbars) for electricity delivery.

Control Options

Pendant control (hanging push-button station).

Radio remote control (up to 100m range).

Operator cabin (for large cranes).

Variable Frequency Drive (VFD)

Ensures precise speed control and reduces mechanical stress.

.

6. Safety Components
Overload Limiter

Electronic sensor to prevent exceeding rated capacity.

Limit Switches

Automatic cutoffs for hoist (up/down) and trolley/bridge travel.

Anti-Collision System

Laser or RFID sensors for multi-crane environments.

Emergency Stop (E-stop)

Instantly cuts power in hazardous situations.

7. Optional Add-Ons
Crane Scales – Integrated weighing systems.

Explosion-Proofing – For hazardous areas (e.g., chemical plants).

Magnetic or Vacuum Lifters – For handling steel plates or fragile loads.

Automation – PLC-based automation for integration with smart factories.

SKETCH

Main technical

 

 

 

Key Advantages of QD Double Girder Overhead Cranes

① High Load Capacity & Stability

Lifting Capacity: Typically 5–550+ tons, making them ideal for heavy industries.

Dual-Girder Design: Provides superior structural strength and load distribution compared to single-girder cranes.

② Longer Span & Greater Hook Height

Wider Coverage: Spans up to 35m+, suitable for large workshops and warehouses.

Higher Lift: Allows more vertical space for stacking or handling tall loads.

③ Precision & Control

Smooth Operation: Equipped with variable frequency drives (VFD) for controlled acceleration/deceleration.

Multiple Control Options:

Pendant control (manual operation)

Radio remote control (wireless, up to 100m range)

Operator cabin (for large cranes)

④ Durability & Low Maintenance

Heavy-Duty Construction: Made from high-grade steel with corrosion-resistant coatings.

Long Lifespan: 20–30+ years with proper maintenance.

⑤ Safety Features

Overload Protection – Prevents lifting beyond capacity.

Limit Switches – Automatic cutoffs for hoist and trolley movement.

Anti-Collision Systems – Prevents accidents in multi-crane environments.

⑥ Customization Options

Explosion-Proof – For hazardous environments (e.g., oil & gas, chemical plants).

High-Temperature Resistance – For foundries and steel mills.

Automation Integration – Compatible with PLC and Industry 4.0 systems.

 

 

Common Applications of QD Double Girder Overhead Cranes

① Steel & Metal Industry

Handling steel coils, plates, and castings.

Ladle cranes for molten metal transport.

② Power Plants & Heavy Machinery

Lifting turbines, generators, and transformers.

Maintenance of large industrial equipment.

③ Shipbuilding & Ports

Moving ship sections, containers, and heavy cargo.

Dockyard material handling.

④ Automotive & Aerospace

Assembly line lifting of car chassis and aircraft parts.

Precision positioning of heavy components.

⑤ Warehousing & Logistics

Handling heavy pallets and storage containers.

Stacking large loads in high-bay warehouses.

⑥ Construction & Infrastructure

Lifting pre-cast concrete segments.

Bridge and tunnel construction support.

 

 

1. Design & Engineering
Customer Requirements Analysis
Load capacity, span, lift height, working class, environment, etc.
Mechanical & Electrical Design
3D modeling with CAD/CAE software
Structural analysis, FEM calculation, and layout optimization
Component Selection
Motors, gearbox, hoisting units, brakes, electrical parts from trusted brands
2. Raw Material Procurement
High-quality materials such as Q235B / Q345B steel for main girder fabrication
Certified and traceable materials for safety-critical components
Inspection and testing of incoming materials (chemical & mechanical properties)
3. Steel Structure Fabrication
Cutting: CNC flame/plasma cutting machines for high precision
Beveling & Drilling: Edge preparation and joint drilling
Welding: CO₂/MIG/MAG welding for main beams, end carriages, trolleys
Welds are tested by ultrasonic or magnetic particle inspection
Straightening: Hydraulic press for removing deformation
Assembly: Girder assembly with strict geometric dimension control
4. Surface Treatment
Shot blasting to Sa2.5 standard for rust removal
Epoxy or polyurethane painting
Primer + intermediate + finish coats (typically 80–120μm total thickness)
Optional: Zinc-rich or corrosion-resistant coatings for marine or outdoor use
5. Machining & Assembly
Machining of wheels, shafts, drums, and pulley groups for tight tolerances
Assembly of:
Crane wheels, end carriages, and coupling systems
Trolley frame with hoisting mechanism
Motor, gearbox, drum, hook, and rope guide
6. Electrical System Installation
Electrical cabinet assembly with Siemens/Schneider/ABB components
Installation of:
Limit switches, overload protectors, anti-collision sensors
Cables, festoon systems, and wireless remote systems
Motors with VFDs for smooth speed control (optional)
7. Inspection & Testing
Dimensional Inspection: Ensuring assembly accuracy
No-load Testing: Trolley travel, crane travel, hoisting function
Load Testing (usually 1.1–1.25× rated capacity):
Static & dynamic tests per national or CE standards
Electrical Testing: Insulation resistance, control logic, emergency stop
Safety Device Test: Limit switches, alarms, brakes, and interlocks
8. Packaging & Delivery
Disassembly of main components for shipping (as required)
Waterproof wrapping, anti-corrosion protection, and steel frame packaging
Custom packing for overseas shipment (container or bulk cargo)
9. Documentation & Handover
Includes:
User Manual
Quality Certificate
Load Test Report
Electrical Wiring Diagram
Maintenance Schedule
Optional: On-site installation supervision, commissioning & 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%.