I have a Singer 15-91 in one of those cases, and always thought that was called a coffin-top. The sales slip for mine is from Sears, Seattle, WA, dated 1937. I believe there are newer ones, chinese origin, that are copies of vintage Singers. You are right to caution about not carrying by the handle on top, even when locked the top moves around too much. I am thinking about putting a luggage strap on it.