Abstract: An improved cutter chain construction for a bottom unloader of a storage structure. A cutter arm is mounted for rotation about the center of the storage structure, and an endless chain travels in an endless path on the cutter arm and carries a plurality of cutting members or hooks that are mounted at spaced intervals along the length of the chain. Each cutting member has a relatively thin body with a sharp leading edge and an outer enlarged head. The cutting members are mounted in a sequence along the length of the chain. A first cutting member in the sequence extends laterally outward from the chain and is disposed in a first plane, while the next succeeding cutting member lies in a second plane disposed at an acute angle to the first plane, whereby movement of the cutting members through the stored material will cut a wedge shaped mass.