Tension Clamp for Thin Material

This is a single-print clamp that tightens onto a sheet of thin material in proportion to the tension on a line attached to the other end -- at least in theory. It works well enough to demonstrate the concept, but in this size not reliably enough for the amount of tension I needed. If it were scaled up it might work better. The force required to keep the jaws tight could be that of gravity as well as tension on a line.
The holes in the outer body are intended both to economize on material a