Described briefly, according to a typical embodiment of the invention, a floor-mounted stationary base frame supports two traveling frames. One of the traveling frames comprises the mattress support frame. The other comprises the side and end walls of a single enclosure surrounding the mattress. Scissors arrangements connect the traveling frames to the base frame whereby the traveling frames are simultaneously operable in opposite directions to raise the mattress while the enclosure is lowered. A brake apparatus permits frame travel only during conscious and controlled operation of a brake release handle.