Fixed cranes, wharf cranes, and grab cranes are equipment used for loading, stacking, and unstacking materials such as wood, reeds, bamboo, waste paper, soil, sand, and stone. These cranes feature a "dual-power" system with both internal combustion engines and 380V electric interchangeability, saving 60% of energy consumption compared to internal combustion engines. They can quickly switch between different hydraulic grabs, enabling multi-functional use. The wharf crane is particularly suitable for grab operations at wharfs for sand and stone, steel market steel lifting, and factory cargo hoisting and lowering. This equipment has low operating costs and low maintenance expenses.
Common safety accidents at docks and ports are often caused by crane hook failures. The outdoor operating environment of port cranes requires careful maintenance of their metal components. Here, I will elaborate on how to carry out the maintenance of crane hooks.
The hook serves as the connection between the crane and the heavy load, so its maintenance is crucial. Therefore, if the lifting height limiter or the hook lock mechanism fails or is damaged, it must not be used anymore; as for those working without proper certification, the leadership should be held accountable.
Hooks are categorized into two types based on their shape: single hook and double hook; and into three types according to their manufacturing processes: sheet hooks, forged hooks, and cast hooks. Currently, the most common type of hook is the forged single hook, while cast hooks are not allowed on cranes. Hooks are widely manufactured using low-carbon steel and carbon alloy steel to address durability and cracking issues.
To ensure safety, hooks must be inspected, and they should be discarded if any of the following conditions are found: 1. Cracks are present. 2. Wear on the critical section is not more than 5% of the original height; hooks manufactured to standard specifications should exceed the original size by 10%. 3. The opening size has increased by 15% from the original. 4. Twisting deformation exceeds 10 degrees. 5. Plastic deformation occurs on the critical section or the hook neck. 6. When the wear on the plate hook sleeve reaches 50% of the original size, the core sleeve should be discarded. 7. When the wear on the plate hook shaft reaches 5% of the original size, the core shaft should be discarded. Additionally, note that the above defects in hooks cannot be repaired by welding.
Safety is a crucial factor in the operation of crane equipment lifting, in addition to monitoring the condition of the ropes, the wear on the hooks should also be given attention to ensure safe production and enhance work efficiency.