I own some IR equipment but nothing like that. I've mainly used their impact guns, compressors, and lift equipment. The small end of your item has a square hole similar to the drive end of a socket. Maybe power was transmitted through the center of your cone to the other side and the slot and/or chain was used to keep the outer shell of the cone from turning. Maybe the "D" shaped drive on the other end fit over a round shaft with a flat edge. Interesting item. I hope you figure it out and let us know.