In our latest successful grab bucket overhead crane project,, we summarized some considerations when designing solutions for users. The customer’s application involves handling bulk materials containing petroleum residues. Some time ago, due to improper maintenance, a fire broke out in the grab bucket operating workshop, causing significant losses and rendering the original Demag overhead crane unusable. Furthermore, the Demag overhead crane had previously frequently shut down due to motor overheating from overwork. Based on the above issues, we redesigned a customized solution for the customer. The new requirements included a lifting height of 15 meters and a total weight of nearly 5 tons for the grab bucket and the medium. The new application requires a lifting height of 15 meters, with the combined weight of the grab bucket and material reaching nearly 5 tons. Our solution is planned as follows: Although the actual material load is only just over 2 tons and the grab bucket self-weight is about 3 tons, due to the special nature of grab bucket applications, the crane is typically designed to an A6/A7 duty class, with each load being constant. Considering the 15-meter lifting height and the need for precise material discharge at the final feed opening, we adopted a 20 ton trolley structure with an 8/2 reeving system, and added a secondary lifting limit switch. At the same time, to ensure sufficient strength redundancy when the forged hook engages with the grab bucket lifting ring — and to avoid potential long-term hook tip fatigue or fracture — we implemented a 90° fixed anti-rotation function to prevent uncontrolled rotation of the grab bucket, improving operating stability. The vertical lifting function (no horizontal displacement during grab bucket lowering) ensures that materials do not spill outside the feed opening during discharge. Since the grab bucket may sway during crane travel, we incorporated an electrical anti-sway control system, which significantly improves handling precision and operational efficiency. For crane power supply, a VAHLE cable reel system was selected, and all cables on the crane use high-quality VAHLE flame-retardant flexible cables. Finally, considering the customer’s corrosive working environment, the entire crane structure and coating system were manufactured to a C5 corrosion-protection standard. The grab bucket is supplied by PEINER SHP, a long-term partner of ours known for excellent processing craftsmanship. The Danfoss remote control system also delivers an outstanding operator experience. Our comprehensive solution and technical proposal ultimately earned the customer’s trust, leading them to choose our solution instead of continuing cooperation with Demag.
The most suitable solution requires a deep understanding of the working conditions and operating habits. If the equipment is incorrectly selected, its stability, reliability, and durability will be greatly reduced. Therefore, we strongly recommend that users provide detailed information about their operating environment. The more complete the information supplied to the manufacturer, the better the opportunity to deliver the most appropriate and reliable solution.