Views: 4 Author: Site Editor Publish Time: 2020-11-25 Origin: Site
The chain hoist is a simple to use and easy to carry manual hoisting machinery. It is suitable for factories, mines, construction sites, agricultural production, and docks, docks, warehouses, etc. for installing machines, lifting goods and loading and unloading vehicles, especially for open air and Operation without power supply has more important functions. The following analyzes the cause of a chain hoist accident:
Case: A chain hoist was used to lift the equipment when a repair factory was overhauling the machine tool. The accident happened to a machine with a lifting weight of 2T, a lifting height of 2.5m, a minimum distance between two hooks of 410mm, and a bracelet tension of 330N when fully loaded. Chain hoist with 2 rows of heavy chain. When the machine tool was in place, nothing happened to the chain hoist during the lifting phase. When the worker started to pull the hoist to slowly lower the machine tool, the lifting chain suddenly broke and the lifting load was lost.
1. In the above accident, the lifting chain of the chain hoist was inspected, and small old cracks were found visible to the naked eye. It can be seen that the internal quality of the lifting chain was defective. This is a hidden danger of fracture that has already existed in this accident.
2. At the time, it was found that the weight of the lathe bed was 2.2t, and the lifting capacity of the hoist was only 2t, which was overloaded lifting, which was directly related to the first breaking of the weak link of the lifting chain.
3. After inspection, it is found that the rest of the unbroken lifting chain has multiple tensile fatigue deformations, and the deformation has exceeded the scrap standard of more than 5% of the original size. In addition, there are many links where the wear amount exceeds the scrap standard of more than 10% of the original size. It has been investigated that the hoist has been used more frequently and has a service life of 7 years. The lifting chain has not been replaced once. It can be seen that the lifting chain has reached the scrap standard and is still in use, which is also an important reason for this accident.