Piher is a Spanish company that makes clamps – all kinds of clamps.

Earlier this year they introduced an interesting attachment. It fits onto the end of one of their F-style clamps and allows you to spike one end of the clamp into timber and clamp with the other end.

It's easier to show what it does than to explain (see video below). I feel certain I have seen something like this before in a purpose-built clamp (or a clamp that had been altered) used for timber-framing or wooden ship building.