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 and to facilitate breaking the inner jaws free after printing.
I printed there without support. There was some stringing and sag, but not enough to impede their functioning.
After printing, press upward on the outer end of the jaws to break them loose from the housing, then pry outward on the spring end of the jaws through one of the side holes in the housing.