unknown antique machine part

75 pound chunk of steel, has wheel bearing in the center, mounting bracket with angle adjustments on the back. On the front there are two springs(tension adjustment?) there are a ring of long allen screws on the face where something has been removed,and each blade can turn about 30 degrees and each has a grease zerk. there are holes at the end of each "blade". I spoke to an expert on windmill parts-and he says not it. Maybe part of a water wheel? part of an industrial fan? Maybe a chunk of a farm implement that ether cut or dug into the ground? It looks like something was bolted with a carriage bolt at the end of each blade where there is a square. I got this at an antique fair in Tucson-and the owner had no ideas. All I can guess is this thing was made to spin-wind,water,electrical-can't tell. Any help from anyone would be greatly appreciated.