This must be what they used before Vise Grips came along? It's a set of pliers - or call them tongs maybe - with two different pivot holes available. And at the end of one handle is a plate with eleven holes, which the opposite handle can fit into. So I think in practice you were supposed to pinch down on whatever it was you wanted to clamp, and then poke the free handle into whichever hole was closest so as to maintain tension on the jaws. It works, kinda clumsily though, but would suffice if there were no vise grips around.
Any ideas about when it was made? By whom? And if it was intended for a specific trade, or just general usage? Thanks!