LH Double Girder Gantry Crane

The electric double-girder overhead crane (typically LH type) is a light-to-medium-duty bridge lifting equipment with the following core structural and performance features:

Metal structure: The main girder adopts a welded box girder design, with web plates precisely cut under CNC control to ensure smooth and accurate stiffness curves. Main welds undergo submerged arc automatic welding and non-destructive flaw detection, followed by whole-girder shot blasting to achieve Sa2.5 grade for welding stress elimination. The surface is treated with zinc-rich epoxy paint (two coats on both sides, 140μm thickness) for corrosion resistance. End girders can feature European-style structures or rigid connections to the main girder via high-strength bolts, ensuring overall precision and stability.

Lifting and traveling mechanisms: The lifting core consists of CD1/MD1-type electric hoists, supporting dual-speed or variable-frequency speed regulation. Some models integrate a "three-in-one" drive system (combining F-class insulated variable-frequency motor, reducer, and brake), featuring compact size, low noise, and sensitive braking (automatic braking within 1 second during power loss). The trolley and bridge traveling mechanisms are separately driven—the trolley moves horizontally along the main girder rails, while the bridge travels longitudinally on elevated tracks. Some models achieve smooth, stepless operation via variable-frequency speed control.

Electrical and control systems: Equipped with phase-loss protection, anti-vibration contactors, and IP55-rated electrical cabinets for corrosion-resistant, easy maintenance. Power supply uses flat cables, zinc-coated sliding rails, and cable trolleys for smooth sliding. Operation modes include ground pendant control, wireless remote control, and cabin operation (open/closed cabins, accessible from side/end/top as needed).