Those are known as toggle clamps, plier clamps, or toggle pliers.
I have seen them used before in welding shops. They are still available new (see links below). I suspect the design pre-dates ViseGrips.
Link to Toggle Clamp on Amazon
Link to Plier Clamp
I have got a slew of these, in various sizes. When you adjust them and close them they overcenter and there is no way they will reopen from the business end unless you spread the handles apart. One of their useful features is that the threaded end can fit up under a lip or avoid an obstruction.
Keep an eye out at garage sales, thrift stores, etc. as they are not cheap.
The majority of mine have no center lever.
I'm on my second glass of wine, so I am pretty smart right now.
One more glass and you'll be positive! LOL
It looks like a 13th century torture implement. It's exact use is best not discussed in polite circles!Anyone know what it is and what it is used for?