Single Girder Top-running Electric Overhead Crane

 

Single Girder Top-Running Electric Overhead Crane: Components Breakdown

A single girder top-running electric overhead crane consists of several key components that work together to provide efficient and safe material handling. Below is a detailed breakdown of its main parts:

 

1. Main Components

① Bridge Girder (Main Beam)

Function: The primary load-bearing structure that spans the width of the runway.

Design:

Box girder (most common for single girder cranes).

Made of high-strength steel (Q235B or Q345B).

Features:

Supports the hoist and trolley.

Designed for minimal deflection under load.

② End Trucks (End Carriages)

Function: Support the bridge girder and allow the crane to move along the runway rails.

Components:

Wheels: Forged steel or ductile iron wheels with bearings.

Drive Motors: AC/DC motors (one or both sides driven).

Buffers/Bumpers: Absorb impact at travel limits.

Rail Sweepers: Remove debris from the runway.

 

③ Hoist Unit

Function: Lifts and lowers the load.

Types:

Electric Wire Rope Hoist (most common).

Chain Hoist (for lighter loads).

Key Parts:

Motor: Powers the lifting mechanism.

Gearbox: Reduces speed and increases torque.

Drum/Rope Guide: Holds and guides the wire rope.

Hook Block: Swivel hook for load attachment.

Brakes: Electromagnetic or mechanical for safety.

④ Trolley (Crab Unit)

Function: Moves the hoist along the length of the bridge girder.

Components:

Frame: Supports the hoist.

Wheels & Drive: Motorized travel along the girder.

Guides: Keeps the trolley aligned.

⑤ Runway System

Function: Provides the track for crane movement.

Parts:

Runway Beams: Steel I-beams or fabricated sections.

Crane Rails: Typically P24, A45, or A55 rails.

Rail Clamps & Fishplates: Secures rails to the beams.

2. Electrical & Control System

① Power Supply

3-phase AC (380V/415V, 50Hz) or as per regional standards.

② Control Options

Pendant Control (Hanging Button Station) – Wired handheld remote.

Radio Remote Control – Wireless operation.

Cabin Control – For larger cranes (rare in single girder).

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③ Safety & Limit Devices

Overload Limiter – Prevents lifting beyond capacity.

Limit Switches – For hoist upper/lower limits and trolley travel.

Emergency Stop (E-Stop) – Cuts power in emergencies.

Phase Protection Relay – Prevents motor damage from power issues.

3. Optional Accessories

✔ Variable Frequency Drive (VFD) – Smoother speed control.
✔ Weighing System – Integrated load measurement.
✔ Anti-Sway System – Reduces load swing.
✔ LED Work Lights – Improves visibility.
✔ Festoon System – Manages power/signal cables.

 

Sketch

 

Main technical

 

Cost-Effective Solution

Lower initial investment compared to double girder cranes

Reduced installation and maintenance costs

More economical for light to medium-duty applications

Space-Saving Design

Compact structure requires less headroom

Ideal for facilities with height limitations

Leaves more usable space below the crane

Lightweight Construction

Lower deadweight reduces building structural requirements

Easier to install and modify

More energy-efficient operation

Simplified Maintenance

Fewer components than double girder cranes

Easier access for inspections and repairs

Lower lifetime maintenance costs

Flexible Configurations

Available in capacities from 1 to 32 tons

Adaptable for various lifting applications

Customizable with different hoist options

Efficient Operation

Smooth and precise load handling

Available with variable frequency drives

Multiple control options (pendant, remote, cabin)

 

Manufacturing Facilities

Assembly line operations

Machine tool handling

Component positioning

Warehousing & Logistics

Loading/unloading operations

Material distribution

Pallet handling

Steel Service Centers

Sheet metal handling

Coil transfer

Bar stock movement

Maintenance Shops

Equipment repair

Machinery installation

Plant maintenance

Light Industrial Applications

Paper mills

Textile factories

Food processing plants

Automotive Industry

Engine assembly

Chassis handling

Component transfer

1. Design & Engineering
Requirement Analysis: Confirm load capacity, span, lift height, automation level, control mode, and safety features based on customer needs.

Structural Design: Design the single girder main beam, end carriages, trolley, and hoist assembly using CAD software.

Electrical & Control Design: Develop control system schematics including PLC programming, motor selection, VFDs, sensors, alarms, and safety interlocks.

Simulation & Validation: Use FEA (Finite Element Analysis) for structural integrity and dynamic simulation for motion control.

2. Material Procurement
Source high-quality steel (Q345B or equivalent) for main beam and components.

Acquire motors, hoists, VFDs, PLCs, limit switches, and alarm systems from trusted suppliers.

Ensure all components meet relevant certifications and standards (ISO, CE, GB).

3. Main Beam Fabrication
Cutting: Steel plates cut to size using CNC flame/plasma cutting machines.

Forming: Roll or shape plates into the I-beam or box girder profile.

Welding: Perform welding of flanges, web, and stiffeners following welding procedure specifications (WPS).

Heat Treatment: Stress relief if necessary to reduce welding deformation.

Machining: Drill holes for end carriage and trolley mounting; machine crane rails if integrated.

Inspection: Check weld quality (X-ray or ultrasonic), dimensions, and surface finish.

4. End Carriage & Trolley Assembly
Frame Fabrication: Cut and weld end carriage frames and trolley frames.

Wheel Assembly: Mount wheels and fit bearings; assemble drive motor and gearbox.

Installation: Attach wheels to frames and mount brakes and limit switches.

Testing: Static and dynamic tests on wheels and brakes for smooth rotation and load bearing.

5. Hoist Assembly
Assemble wire rope or chain hoist on the trolley.

Install hook block, safety latch, load limiter, and load sensors.

Connect hoist motor, gearbox, brake, and encoders.

Conduct functional tests on hoisting speed, lifting capacity, and braking.

6. Electrical Wiring & Control System
Install motor cables, control cables, and communication lines.

Mount PLC, VFDs, contactors, and safety relays in the control cabinet.

Wire limit switches, alarms, emergency stop, and sensors.

Program PLC with automated control logic, safety interlocks, and diagnostics.

7. Surface Treatment
Cleaning: Remove rust, oil, and debris from all steel parts.

Primer Coating: Apply anti-corrosion primer.

Final Paint: Spray high-durability industrial paint to protect against wear and corrosion.

Curing: Allow proper drying time to ensure finish quality.

8. Pre-Installation Testing
No-Load Tests: Run crane, trolley, and hoist without load to verify movement, speed, and control.

Load Test: Perform rated load test per standards to ensure lifting capacity and structural integrity.

Safety Device Check: Verify operation of overload limiter, limit switches, emergency stop, and alarms.

Automation Validation: Test automated sequences, positioning accuracy, and sensor feedback.

9. Packing & Shipping
Disassemble parts if necessary for transport.

Protect components with rust-proofing, padding, and secure packing.

Prepare documentation including user manuals, maintenance guides, and test certificates.

10. Installation & Commissioning (On-Site)
Reassemble crane components at customer site.

Align crane rails and secure runway structure.

Connect power and control wiring.

Calibrate sensors and test automated control functions.

Train operators and maintenance personnel.

Hand over documentation and certification.
 

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%.