Client: A regional distribution center for automotive parts.
Challenge: The client was constructing a new high-bay warehouse to consolidate inventory and streamline logistics. Their primary need was to handle heavy, palletized engine blocks and transmission assemblies efficiently within the confined indoor space. Key constraints included a limited building height, requirements for precise and safe load positioning, and the necessity for reliable, round-the-clock operation with minimal maintenance disruption.

Solution: Dongqi’s Indoor Double Girder Overhead Crane with 35-Ton Capacity

After a detailed site assessment, our engineering team recommended a customized Double Girder Overhead Crane as the core of their warehouse construction material handling system. The solution was specifically engineered for superior indoor performance and long-term material handling efficiency.

Technical Analysis: Indoor-Adaptive Design of the Double Girder Bridge Crane

The client’s scenario highlights why a standard crane is often insufficient for demanding indoor applications. Our design focused on several critical adaptations:

1. Optimized Hook Approach & Low Headroom Design:
   The double girder structure allows the hoist trolley to be mounted between the girders, not under them. This configuration provides a significantly lower hook approach distance compared to single girder cranes. For the client, this meant maximizing the usable lift height under the warehouse roof beams, allowing for higher storage racks and better space utilization—a crucial factor in warehouse construction economics.
2. Enhanced Stability and Durability for Heavy-Duty Cycles:
   The 35-ton capacity handling demands a robust framework. The double girder design inherently offers greater torsional rigidity and strength than a single girder. This translates to minimal deflection under full load, ensuring smooth and precise trolley travel along the bridge. For the operator, this means accurate load spotting without sway, enhancing both safety and operational speed. The rigid structure also withstands the stresses of frequent starts and stops common in high-cycle warehouse operations.
3. Enclosed Design for Cleaner Operation:
   Indoor environments, especially those storing sensitive components, benefit from reduced contamination. Our crane’s bridge and trolley feature enclosed designs where possible, preventing grease and debris from falling onto stored goods or work areas below. This aligns with modern warehouse construction standards for cleanliness and order.
4. Precision Control and Noise Mitigation:
   To integrate seamlessly into a busy working environment, the crane was equipped with variable frequency drives (VFDs) on all major movements: hoist, trolley, and bridge. VFDs allow for soft, controlled acceleration and deceleration, enabling millimeter-precision positioning essential for handling expensive automotive parts. Furthermore, this control dramatically reduces mechanical shock and operational noise, creating a better environment for ground staff.
5. Reliable Indoor Power Delivery:
   For long indoor overhead crane travel paths, we recommended an energy conductor system (closed busbar system) instead of cable reels. This system provides a consistent, spark-free power supply to the crane, with lower maintenance needs and higher reliability—key for minimizing downtime in a fast-paced distribution center.

Result:
The installed 35-ton Double Girder Overhead Crane became the backbone of the client’s new logistics flow. It enabled safe, fast, and precise movement of heavy loads from receiving docks to storage racks and onto outbound loading areas. The robust design ensured high uptime, while the precision controls reduced product handling risks. The client reported a measurable increase in throughput and a significant reduction in manual handling bottlenecks, fully realizing the planned material handling efficiency goals of their new facility.

For Your Warehouse Project:
If your warehouse construction or retrofit project involves moving heavy unit loads indoors, the engineering principles demonstrated in this case are critical. A Double Girder Design is not merely an option but a necessity for serious 35-ton capacity applications where space, reliability, and precision are paramount. Contact Dongqi Crane to discuss how a customized Indoor Overhead Crane solution can be designed into your plans from the outset.