Can't help you with designer or manufacturer, but your table is referred as a convertible coffee table; ideal for tight living quarters. The hinge also looks to be quite old. I would guess Danish 50's for the piece, although I have seen similar brass hinges on Norwegian tables as well. Maybe that might help refine your search,
Not Børge Mogensen. It looks nothing like his work. Also he is rather well known. if this were by a well known designer someone would have recognized it by now.
I would suggest you start by looking for other coffee tables identical to this one. If you are lucky, that will lead you to a marked one. Or perhaps a "made in Denmark" or Sweden or Norway or possibly a few other places. And if you are lucky some research into the company will lead you to a designer. Although it is entirely possible that it is a generic piece also.
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