Ah. A rare find indeed. It's a... well, erm.... Well there isn't a delicate way to say this, so I'll come right out with it. It's part of a colonial-era chastity belt. Made of the finest steel they could produce at the time, but occasionally one will find one made of brass. I believe that mudwhale had found a brass one a few years back. Of course, in your case, the top cover is missing, probably pried off by someone desparate.... Always interesting stories behind these kind of finds
To me it looks like a foot pedal or attachment to climb up on tractor or something. The three teeth seem like there purpose is to keep you from slipping. I’m impressed with the clear stand you used to get pictures… nice.
It's a first generation Budweiser Stake mounted bottle opener for farmers. They could take it along during the work day and just hammer it into the ground at the next work spot.