Seat which converts into a bed

An article of furniture convertible from seating to a bed, said article of furniture comprising:

• a seating portion having a seating frame and a seating surface lying in a plane;
• a back rest connected to said frame and having arms pivotally connected to the back rest and to the frame (1) and enabling said back rest to assume an upright position at a rear of said seating surface in a seating position in which an underside of said back rest lies on said rear of said seating surface and a bed position in which a back of said back rest is coplanar with said seating surface;
• an upholstery fabric attached at one side to a front underside of said seating frame and at an opposite side to the underside of said back rest, whereby said upholstery fabric covers said seating surface in said seating position and an upper side of said upholstery fabric is exposed in said seating position;
• and
• a double layer of a drill material extending in said seating position only over said seating surface and underlying said upholstery fabric in said seating position, but secured to said underside of said backrest so as to stretch in a single layer over said seating surface and said back of said back rest in said bed position.