Support structure for sofa beds, with pull-out, raisable auxiliary bed

A sofa bed with a pull-out, raisable auxiliary bed, comprising:

• a seat-back pivotable relative to the sofa bed between a generally vertical position in which the top surface of the sofa bed is adapted for sleeping on, and a slanted position in which the seat-back is adapted to provide a back support for a seated user, said seat-back, in its slanted position, being adjustable laterally relative to the top surface of the sofa bed to thereby provide back support for seated users of different sizes, with the auxiliary bed comprising;
• an upper frame carrying a support means for a mattress;
• two lower bars parallel to said upper frame;
• a plurality of rods transverse to a larger dimension of said upper frame and connecting said upper frame to said lower bars;
• means for blocking movement of said upper frame beyond a raised position;
• and
• means for balancing the weight of said upper frame, whereby the auxiliary bed can be moved between a first, stored position, underneath the sofa bed, and a second pulled-out position adjacent to and at substantially the same height as the sofa bed.