I've been wondering how those things worked.
In the most recent issue of Farm Show, a guy told of dragging a pole behind him on a long chain. I think he had the chain hooked about a foot or so behind the end of the pole, and he would circle the sprout to catch it in the vee between the chain hookup and the pole. He said that after getting it pulled, he could circle in the opposite direction and it would unhook by itself. I'm skeptical, but there's a piece of a broken power pole laying in the edge of the pasture, and I'm gonna have to try it. Probably just strip the limbs from the sprout, but who knows til it's tried? I especially like the idea of not having to climb on and off of the tractor a hundred times. The slip ring idea works - I used my long furnace poker to get the chain in position under the limbs around the sprout, but again, it's on and off and on and off the tractor.