Ld Electric Single Girder Bridge Crane

Core Components: Gearbox, Motor, Gear

Place of Origin: Henan, China

Warranty: 1 Year

Weight (KG): 10000 kg

Video outgoing-inspection: Provided

Machinery Test Report: Provided

Selling Units: Single item

Single package size: 600X300X300 cm

Single gross weight: 200.000 kg

1. MAIN STRUCTURAL COMPONENTS

1.1 Main Girder Assembly

The core load-bearing element - typically a standardized I-beam or box girder.

Main Girder: Single beam spanning the work area.

Types:

Rolled Steel I-beam (GB/T 706): For capacities ≤10t and spans ≤16m.

Welded Box Girder: For capacities >10t or spans >16m for better rigidity.

Features: Factory-drilled holes for connections, pre-cambered to counteract deflection.

Girder End Connections: Machined plates welded to girder ends for bolting to end trucks.

Trolley Running Rail: Not a separate rail - the bottom flange of the main girder serves as the running surface for the hoist trolley wheels. Critical wear surface.

1.2 End Truck Assemblies (2 Sets)

Support structures at each end of the girder for bridge travel.

End Truck Frame: Steel fabricated frame housing wheels and drive components.

Travel Wheels: Double-flanged steel wheels (typically 4 total, 2 per end truck).

Wheel Axles & Bearings: Standard heavy-duty ball or roller bearings.

Drive End Truck: Contains the bridge drive mechanism.

Idler End Truck: Passive end with wheels only.

2. HOIST & TROLLEY SYSTEM

2.1 Electric Hoist Unit

Integrated lifting device - the heart of the crane.

Hoist Motor: Brake motor (usually 1.5-30kW depending on capacity).

Gearbox: Multi-stage helical gear reducer.

Wire Rope Drum: Grooved drum for rope spooling.

Wire Rope: 6x19 or 6x37 class steel wire rope.

Hook Block: Swivel hook with safety latch, rated for crane capacity.

Upper/Lower Limit Switches: Mechanical or rotary limit switches to prevent over-travel.

Overload Limiter: Mechanical or electronic device (often optional on basic LD models).

2.2 Trolley Frame

Simple steel frame connecting hoist to main girder.

Trolley Frame: Channel or box steel construction.

Running Wheels (4): V-grooved or flat wheels that grip the bottom flange of main girder.

Trolley Drive Motor: Small brake motor (0.2-1.5kW) for cross-travel motion.

Trolley Gearbox & Drive Wheels: Reducer driving one or two wheels.

Trolley Buffer: Rubber or spring buffers at ends of frame.

 

3. DRIVE & TRANSMISSION SYSTEM

3.1 Bridge Long Travel Drive

Bridge Drive Motor: 0.8-4kW brake motor mounted on drive end truck.

Primary Gearbox: Right-angle gear reducer.

Drive Shaft (Line Shaft): Long steel shaft connecting both end trucks (older design).

"Three-in-One" Drive Units: Modern design integrating motor, brake, and gearbox in one compact unit (one per end truck for synchronized drive).

Couplings: Flexible pin-type or gear couplings.

3.2 Trolley Cross Travel Drive

Integrated into trolley frame as described above.

4. ELECTRICAL SYSTEM

4.1 Power Supply System

Main Power Source: 380V/50Hz/3-phase (standard Chinese industrial power).

Sliding Cable System (Festoon):

Festoon Trolley: Carries power cables along runway.

C-Hook Rail: Mounted on wall or column for festoon travel.

Power & Control Cables: Flexible rubber-sheathed cables.

Cable Reel System (alternative): Spring- or motor-driven reel for bridge power.

Collector System (for cab-operated versions): Conductor bars with shoe collectors.

4.2 Control System

Pendant Control Station:

Hanging push-button box with 6-8 buttons (Up/Down, Left/Right, Forward/Back, Emergency Stop).

Low-voltage control circuit (typically 36V or 48V for safety).

Control Panel/Box:

Contactors: For motor control (reversing contactors for hoist, bridge, trolley).

Control Transformer: Steps down to safe voltage.

Circuit Breakers/MCCBs: For circuit protection.

Terminal Blocks: For wiring connections.

Limit Switches:

Hoist Upper/Lower: Rotary cam type.

Bridge & Trolley End Limits: Lever-arm or plunger type.

Emergency Stop: Mushroom button on pendant and often at runway ends.

5. SAFETY & AUXILIARY DEVICES

5.1 Mandatory Safety Devices (per LD standard)

Overload Limiter: Prevents lifting beyond rated capacity.

Limit Switches: For all three motions (hoist, trolley, bridge).

Emergency Stop Buttons: Minimum one on pendant.

Hook Safety Latch: Prevents load from slipping off hook.

Audible Warning Device: Buzzer or bell (often activated when bridge moves).

5.2 Optional Safety & Convenience Devices

Anti-Collision Device: For multiple cranes on same runway.

Crane Weigher: Digital readout of load weight.

Infrared Safety Scanner: Creates invisible safety zone.

Voltage Protector: Protects against phase loss or voltage fluctuation.

6. RUNWAY SYSTEM (Not always supplied with crane)

6.1 Runway Beams

Steel I-beams (GB/T 706) mounted on building columns.

Must be precisely aligned and leveled.

6.2 Crane Rails

A45, A55, A65, A75, A100 steel rails (light crane rail series).

Rail Clips & Bolts: For securing rail to runway beam.

6.3 Rail End Stops/Bumpers

Mechanical stops at both ends of runway to prevent over-travel.

.

7. OPERATOR INTERFACE OPTIONS

7.1 Standard Control

Pendant Push-button Station: Most common (90%+ of LD cranes).

7.2 Alternative Controls

Radio Remote Control: Infrared or 2.4GHz digital radio.

Cab Control: Enclosed operator's cab mounted on bridge (less common for LD).

SPECIAL NOTES ON LD STANDARD COMPONENTS

Standardization: All major components (hoist, end trucks) follow dimensional and performance standards for interchangeability.

Material Specifications: Steel is typically Q235B or Q345B per Chinese standards.

Duty Rating: Components selected for FEM 1M/2M (A3/A4) duty cycle - 150-300 starts per hour.

Environmental Rating: Standard IP44 for outdoor components, IP54 for hoist motor.

Wiring: Color-coded per Chinese electrical standards (Phase A-Yellow, B-Green, C-Red, Neutral-Blue, Ground-Yellow/Green).

Sketch

 

Main technical

 

1. Cost Efficiency (The Primary Advantage)

30-50% Lower Initial Cost vs. double girder cranes

Reduced Installation Costs: Lighter weight requires less robust building support

Lower Maintenance Costs: Simpler design with fewer components

Energy Efficient: Smaller motors consume 20-40% less power than equivalent double girder cranes

2. Space & Structural Advantages

Optimal Headroom Utilization: Hoist runs under the beam, maximizing lift height in low-clearance spaces

Lightweight Design: 40-60% lighter than comparable double girder cranes

Minimal Building Load: Reduced structural requirements for supporting columns and runways

Compact Design: Ideal for facilities with limited space between columns

3. Operational Benefits

Simple Operation: Intuitive pendant control requiring minimal operator training

Quick Installation: Pre-fabricated components allow installation in 1-3 days

Easy Maintenance: Accessible components and straightforward troubleshooting

Flexibility: Can be adapted for various lifting heights and spans within standard ranges

4. Reliability & Standardization

Proven Design: Mature technology with decades of refinement

Component Interchangeability: Standardized parts readily available

Consistent Performance: Predictable operation within designed parameters

Long Service Life: 15-25 years with proper maintenance

 

1. Manufacturing & Workshops

Industry	Specific Applications	Typical Capacity
Machine Shops	Loading/unloading CNC machines, lathes, milling centers	2-5 tons
Automotive Repair	Engine removal, transmission handling, vehicle lifting	1-3 tons
Metal Fabrication	Moving steel plates, finished products, tooling	3-10 tons
Assembly Lines	Component transfer between workstations	0.5-2 tons

 

2. Warehousing & Logistics

Application	Benefits	Common Configuration
Loading Docks	Truck loading/unloading	3-5t, 10-16m span
Storage Areas	Pallet handling, rack servicing	2-3t, 12-18m span
Distribution Centers	Order picking, inventory movement	1-2t with multiple cranes

 

3. Maintenance & Service Facilities

Power Plants: Maintenance of pumps, valves, turbines (5-10t)

Water Treatment Plants: Pump and motor handling (3-5t)

HVAC Service: Chiller and boiler maintenance (2-5t)

Equipment Repair: Factory machinery maintenance and overhaul

4. Light Industrial Applications

Food Processing: Equipment maintenance, ingredient handling (1-3t)

Pharmaceutical: Cleanroom equipment installation (1-2t)

Plastics Manufacturing: Mold changing, machine servicing (3-5t)

Printing Industry: Roll handling, press maintenance (2-3t)

 

5. Commercial & Institutional

Aircraft Hangars: Light component handling (1-3t)

Theaters & Studios: Lighting rig movement, set construction (0.5-2t)

Research Facilities: Laboratory equipment installation (1-2t)

Educational Institutions: Technical training workshops (1-3t)

 

Stage 1: FEM-Based Design & Engineering

This is the most critical stage, where the crane's operational profile is defined according to FEM 1.001.

Client Requirement & FEM Classification:

Determine the exact FEM Duty Group (e.g., 2m, 3m, 4m) and Load Spectrum (e.g., L1, L2, L3) based on the client's operational data (hours of use per day, lifts per hour, average load as a percentage of capacity).

Advanced Engineering Calculations:

Structural Analysis (FEA): The single girder (I-beam or box) is modeled and calculated for deflection and stress under dynamic loads specific to the assigned FEM class, not just the static load.

Component Life Calculation: The expected number of cycles for the hoist, trolley, and travel drives is calculated. Components are then selected whose designed lifespan meets or exceeds this number.

Fatigue Analysis: Critical welded connections and structural elements are analyzed for fatigue life according to the FEM standard's requirements for the duty group.

Bill of Materials (BOM): Every component, from the hoist motor to bearings and electrical contacts, is specified from suppliers who can provide components rated for the required FEM duty.

 

Stage 2: Material Procurement & Preparation

Procurement: Sourcing certified steel and FEM-classified components. For example, procuring a hoist that is explicitly rated for FEM 3m duty, not just a generic hoist of a certain capacity.

Material Preparation: Steel is cut and prepared. For higher FEM classes (e.g., 4m), more stringent material certifications and preparation standards may apply.

 

Stage 3: Structural Fabrication & Assembly

Girder Fabrication:

The main girder is fabricated, often from a rolled I-beam for lighter classes or a welded box for higher rigidity in moderate classes.

Welding: All welds are performed by certified welders using procedures qualified for the specific steel grades. Weld quality is critical for achieving the calculated fatigue life.

Dimensional Verification: The girder is checked for straightness and camber (a slight upward bend) to ensure it meets the deflection criteria under load as per the design.

 

Stage 4: Mechanical Assembly

End Truck Assembly: Wheels, axles, and bearings are assembled into the end trucks. The wheel and bearing sizes are directly influenced by the FEM class, which determines the total number of wheel revolutions over the crane's life.

Bridge Assembly: The main girder is connected to the end trucks.

Trolley and Hoist Mounting: The FEM-rated hoist unit is mounted onto the trolley, which is then placed on the girder.

 

Stage 5: Electrical & Control System Installation

Component Installation: Electrical panels, contactors, and relays are installed. These are selected for their mechanical and electrical endurance, which must align with the number of operating cycles in the FEM classification.

Wiring: All cabling is installed according to the schematic, with a focus on secure and protected routing to prevent failure.

Safety Devices: Limit switches and overload protection devices are installed and calibrated.

 

Stage 6: FEM-Compliant Testing & Inspection (FAT)

The crane undergoes rigorous testing that reflects its FEM classification.

Visual & Dimensional Inspection: Verification of all components and workmanship.

No-Load Test: All motions are tested for smooth operation, noise, and alignment.

Load Testing:

Static Load Test: Lifting a test load of 125% of the rated capacity to verify structural integrity and brake hold. This is a universal requirement.

Dynamic Load Test: Lifting 110% of the rated capacity and running it through all motions. The test duration and cycles may be more extensive for a higher FEM class to simulate its intense duty cycle.

Functionality & Safety Tests: All safety devices are tested to ensure they can perform reliably for the required number of cycles.

 

Stage 7: Dismantling, Painting & Packaging

Dismantling: The crane is disassembled for shipment.

Painting: A corrosion-protection paint system is applied.

Documentation & Certification: Crucially, the manufacturer prepares a FEM Conformity File or certificate, stating the crane's duty class and confirming it was built to the standard.

 

Stage 8: Site Installation & Commissioning (SAT)

Erection: The crane is reassembled on the client's runway.

Final Commissioning & SAT: The crane is tested again on-site to ensure it was installed correctly and performs as intended.

Handover: The FEM documentation is provided to the client, along with 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%.