The attachment applies to units of warehouses, docks and chemical loading and unloading operations. Has the advantages of reasonable structure, compact, easy to operate, action-safe, reliable, Omission from small, high efficiency, light weight, easy maintenance. The genus with different diameter barrel, adjust the clip off the distance between the height and the stand, and can at the same time handling the different specifications of the barrel, to resolve the plight of a machine-specific, and maximize the use of the locomotive.