Three-in-one sofa bed

A three-in-one sofa bed comprising:

• a bedstead assembly;
• a sofa cushion and sofa seat assembly fixedly connected to the bedstead assembly;
• a moveable coffee table;
• and
• a mattress and mattress frame assembly, in which a proximal section thereof is pivotably connected to a rear section of the bedstead assembly to enable the mattress and mattress frame assembly to be rotated with respect to the bedstead assembly between a horizontal position and a vertical position, wherein in the horizontal position, the mattress and mattress frame assembly straddles the sofa cushion and sofa seat assembly and the movable coffee table to form a bed for sleeping;
• while in the vertical position, the sofa cushion and sofa seat assembly and the movable coffee table are exposed;
• said mattress and mattress frame assembly being slidably connected to the bedstead assembly to enable the mattress and mattress frame assembly to be horizontally movable between a position departing from the bedstead assembly and a position retracting towards the bedstead assembly, in which the position where the mattress and mattress frame assembly retracts towards the bedstead assembly is a position where the mattress and mattress frame assembly is pivotably connected to the bedstead assembly;
• wherein the bedstead assembly includes:
• two ground-mounted side plates on a left side and a right side, respectively;
• a rear plate;
• an upper beam connecting upper ends of the two ground-mounted side plates;
• a curve-shaped movable bedstead back rest pivotably connected to the upper beam by virtue of hinges and movable between a stretch position when rotated rearwards to form a back rest and a position contacting the rear plate when rotated forwards;
• a pulley beam extending horizontally and fixed to a rear part of each of the ground-mounted side plates at a position slightly lower than the middle of each of the ground-mounted side plates respectively;
• at least three pulley bracket assemblies provided systematically at end sections and a middle section of the pulley beam;
• and
• pulleys supported on the pulley bracket assemblies at an upper front position with respect to the pulley beam, in which central axes of the pulleys extend in a left-to-right direction horizontally;
• said sofa cushion and sofa seat assembly includes a sponge cushion and a sofa seat, the sofa seat includes a top plate, two side plates, separators, a bottom plate and several drawers, in which the two side plates of the sofa seat are fixedly connected to the two ground-mounted side plates respectively, and the pulley beam is fixedly connected to the top plate of the sofa seat.