Upper package lower fancy gantry crane

Upper closed box girder main beam:采用 box-type welded structure (primarily made of Q355B high-strength steel), with a rectangular closed cross-section. The torsional stiffness is over 40% higher than that of truss-type main beams, effectively distributing loads and reducing deflection deformation during long-span operations (e.g., for a 20-ton model, deflection ≤ L/1000 at a 32-meter span). ensuring stability during heavy-load (5-50t) lifting operations. Additionally, the enclosed structure protects internal walkways, cables, and transmission components from rain and dust, thereby extending the equipment's service life.

Lower lattice-type gantry crane legs: The legs are fabricated using angle steel or channel steel welded into a triangular lattice-type structure. The open design significantly reduces the equipment's self-weight (20%-30% lighter than fully enclosed gantry cranes), thereby decreasing the load on the foundation (reducing foundation bearing capacity requirements by 15%-20%) and saving on foundation construction costs. Additionally, the trellis structure has a low wind resistance coefficient (≤0.5), offering superior wind stability compared to fully enclosed models in open, windy environments such as ports and yards, and can withstand gusts of up to 8-10 on the Beaufort scale.

Wider operating range: Span coverage of 7.5–32 m (30% larger than single-girder gantry crane models), lifting height up to 6–24 m, with adjustable leg height to accommodate different site clearance requirements (e.g., factory eaves, container stacking areas). The smaller tonnage models (1-5 tons) emphasize flexible operation, while the larger tonnage models (10-20 tons) can meet the lifting requirements for long items (such as steel beams, precast panels) and heavy equipment.

Highly adaptable work level: Work levels are designed according to tonnage classification. Models ranging from 1 to 2 tons are classified as A3-A4 (light load, low frequency, such as sporadic loading and unloading in warehouses), while models above 3.5 tons are classified as A4-A5 (medium load, medium to high frequency, such as assembly line support in workshops and daily operations at ports). Some customized models can be upgraded to A6 (continuous operation) to meet the demands of different work conditions.

Precise speed control and smooth operation: The hoisting mechanism uses dual-speed or variable-frequency speed control (e.g., the 20t model has a hoisting speed of 0.4–4 m/min), ensuring smooth positioning at low speeds under heavy loads and efficient transportation under light loads; Trolley travel speed: 20–35 m/min; main crane travel speed: 30–50 m/min. The drive system is equipped with SEW or ABB motors, minimizing start/stop impact and achieving positioning accuracy of ±5 mm.

The upper-box, lower-truss gantry crane uses a “strong upper, light lower” structural combination that solves the problem of insufficient stability under heavy loads in truss-type main beams while overcoming the shortcomings of excessive self-weight and high wind resistance in all-box-type models. It is one of the optimal solutions for outdoor medium- to heavy-duty, large-span work scenarios in terms of strength, economy, and environmental adaptability.