Can someone help my identify...

[mhpembe]

I saw this tool hanging on a wall in an old photograph. It is made entirely of wood and I cannot figure out what it was used for. AI though it was a ruler, which is clearly wrong. There was a second version in which the hook on the right side was actually a metal hook. I'm thinking maybe it was used for stretching something. But what would it be called?

 

[neophyte]

My guess would be an antique wood ratcheting clamp, but in that case it would be missing the other end were it screw adjusts for tightening the clamp.
Other items were made similarly, from adjustable legs for tables, to lamp stands.

 

[honcho]

Reminds me of the tightening mechanism on a modern wood baby gate. While I don't know what it's called, I agree that it could be used for stretching or holding open something with pressure on one or both sides.

 

[joecon]

It is a jack, look at the teeth they hold the wrong way for a clamp.