Once a loom came to live with me, free to a good home. It's not sturdy enough to be a good rug loom, so I use it for placemats and table runners. It's got a rich history--which I won't go into here, for lack of time. Google Hartland, Michigan and Osma Gallinger-Todd to explore the history of a Michigan weaving Mecca in the 1930s.
I'm posting these photos of the brake system of my Cromaine Crafts loom for those who might also have stumbled on one of these treasures and need a bit of help in putting it together. The brake is a friction brake. The chain attaches to a stationary hook at the top, wraps around the beam and hooks again at the bottom on the movable foot pedal. The pedal is held in place by a large spring, which attaches to a stationary hook at the base of the loom.
To advance the warp, you step on the pedal, which releases the tension of the chain. This allows the beam to rotate toward you. Let off the pedal, and tighten up the warp again and you're on your way.
We replaced the plain warp beam with a homemade sectional beam, and then had some trouble with the brake slipping. So we added a piece of rubber under the chain, to give it a bit more "grab".