Would really love to see a picture of this one!
Lightly constructed beds, rather like the folding kind, were small enough to be kept under the the 4 posted beds when not required. They were used by nurses/servants attending sick people or as extra accommodation for an unexpected visitor. They even made small chests of drawers with dummy fronts - the door would swing open to reveal a folding bed which could be pulled out when needed.
These were also known as truckle beds and these days they are manufactured as trundle beds.
In the late 1800's they also made folding beds that could come out of closets and cabinets that soon became "Murphy Beds" which was (Cabinets were designed after some created in 15th century)....The folding mechanism was developed in the US by Mr. Murphy and was patented. They became very popular! THey also made Murphy sofas'!
There was a company that even made "Ta-Beds" - tables that became beds. (Ta-Bed Company in Chicago.)
Hope this helps!