I've alway heard them called logging tugs. The ones I've used had the hooks at an inconvenient spot and were always catching my horse on the leg. Maybe I was doing something wrong.
I bought a heap of random stuff at an auction and there were several logging tugs in the mix whose hooks that had been crudely cut out of 3/8 inch steel plate with a cutting torch.

I addd them to my collection of horse-related oddities.