Are these adjustment screws? I'm guessing it is some type of spreader. Because of its size and assuming it is made of brass, it can't be for anything very heavy duty. Am I on the right track?
Those are adjustment screws and it is not for anything heavy duty. However it is not a spreader, I'd describe it as a precision instrument that actually does the opposite of what you think of as the primary intention of a 'spreader'.