In this answer I advised the OP to use what I called a 'toggle latch' or 'draw latch'. Do these things have a proper name?
In the U.S. the item you refer to is most often called a draw catch. There are other names, depending on manufacturer and purpose, but I worked 19 years in commercial and residential hardware supply and we always called that a draw catch.
I know them as an over centre latch.