MGB Double-Girder Semi-Gantry Crane for High-Capacity Lifting

The MGB Double-Girder Semi-Gantry Crane features a double-girder load-bearing structure. Compared with a single-girder semi-gantry crane, its two main girders distribute the trolley and lifted loads across both girders, providing higher load capacity and greater structural rigidity for medium-to-heavy material handling. One side is supported by a ground leg and rail, while the other runs on an existing workshop crane runway beam. This design enables vertical lifting, longitudinal travel, and cross-travel of materials, meeting material-handling needs both inside the workshop and in adjacent outdoor areas.

Equipped with a winch trolley as the lifting mechanism, the crane is suitable for intermittent and repetitive handling of equipment and materials. Compared with full gantry cranes with support legs on both sides, the double-girder semi-gantry design reduces ground-leg and rail occupation, making it well suited for existing workshop upgrades, single-side rail connections, and continuous indoor-to-outdoor material transfer.

MGB Double-Girder Semi-Gantry Crane Advantages and Disadvantages

MGB Double-Girder Semi-Gantry Crane Advantages

• Double-Girder Structure for Higher Loads: The double-girder design provides more stable load support and higher lifting capacity for medium-to-heavy loads, heavy equipment, and larger-span lifting operations.

• Compact Layout for Limited Spaces: The overall structure is compact, with a low overall height and small footprint, allowing flexible operation in low-headroom workshops and narrow passages.

• More Efficient Indoor-to-Outdoor Transfer: One side travels along the existing workshop runway while the other runs on a ground rail, allowing one crane to cover connected indoor and outdoor work areas.

• Flexible Control Options: Supports multiple control methods, including cabin control, pendant control, wireless remote control, and PLC interlocking control, to suit different operating distances and material-handling requirements.

• Multiple Lifting Device Options: The MGB Double-Girder Semi-Gantry Crane can be configured with hooks, grabs, electromagnetic lifting magnets, and other lifting devices to meet the lifting and transfer requirements of different material types.

MGB Double-Girder Semi-Gantry Crane Disadvantages

• Higher Equipment Cost: The double-girder structure uses more steel and requires more complex supporting components and travel mechanisms, so its overall purchase cost is typically higher than that of a single-girder semi-gantry crane.

• Higher Dead Weight and Workshop Requirements: With a larger overall weight, the crane places higher load-bearing requirements on workshop runway beams, columns, rails, and foundations.

• Higher Installation and Maintenance Costs: The more complex structure requires more installation work, while subsequent inspection, servicing, and maintenance costs are also relatively higher.

MGB Double-Girder Semi-Gantry Crane Core Components

The winch trolley is the core lifting component of a Double-Girder Semi-Gantry Crane. It is typically installed between the two main girders and is responsible for vertical lifting, lowering, and cross-travel of loads. Its advantages include:

Advantages of Winch-Type Trolleys

• Suitable for Medium-to-Heavy-Duty Lifting: The lifting mechanism can be configured according to lifting capacity, lifting height, and duty class, making it suitable for higher capacities, greater lifting heights, and more demanding material-handling applications.

• More Stable Lifting Arrangement: Running between the two main girders, the trolley provides a more stable load arrangement for the drum, wire rope, and pulley system, making it suitable for large spans and heavy structural components.

• Greater Lifting Configuration Flexibility: Drum size, reeving ratio, lifting speed, and control methods can be configured according to site requirements, allowing better adaptation to different loads and operating cycles.

Structural Feature of Winch-Type Trolleys

The diagram below illustrates the main structure and component layout of the winch trolley on the MGB Double-Girder Semi-Gantry Crane, providing an overview of its lifting, travel, and braking systems and how they work.

The winch trolley uses a lifting motor to provide power. After speed reduction and torque amplification through the reducer, the motor drives the drum to wind and unwind the wire rope, completing load lifting and lowering. The brake holds the suspended load in position when the mechanism stops. The complete lifting mechanism and load are supported by the trolley frame, while the wheel assembly transfers the load to the two main girders for shared support. The reducer provides the torque required for lifting, and the double-girder structure distributes the forces from the trolley and load, forming the structural basis for medium-to-heavy-duty lifting with the MGB Double-Girder Semi-Gantry Crane.

During load transfer, the load force is transmitted through the wire rope to the drum and lifting mechanism, then distributed through the trolley frame and wheel assembly to the two main girders. This reduces the concentration of load on a single main girder. The larger load-bearing sections and structural rigidity of the double girders help control structural deformation under heavy loads. For projects requiring both main lifting and auxiliary lifting, the MGB Double-Girder Semi-Gantry Crane can also be configured with a winch trolley featuring main and auxiliary lifting mechanisms to meet different load and lifting-task requirements.

MGB Double-Girder Semi-Gantry Crane Selection Guide

The MGB Double-Girder Semi-Gantry Crane is suitable for projects requiring greater lifting capacity and a semi-gantry runway arrangement. Confirm the following conditions when selecting the crane:

• A single-girder semi-gantry crane cannot meet the required load capacity.
• A double-girder structure and winch trolley are required.
• A usable workshop runway is available on one side.
• The site can accommodate the wheel loads and foundation requirements of a double-girder crane.