Sofa-bed assembly

In a sofa-bed assembly having a series of sections pivoted to one another in succession, the sections being foldable between a collapsed sofa condition and an extended bed condition, and the series of sections including a rear vertical section, a lower horizontal section, a front vertical section, and an upper horizontal section,

• a mattress folded and compressed within the series of sections when the latter are in the collapsed sofa condition, the folded mattress pressing upwardly against the lower face of the upper horizontal section tending to pivot that section, with respect to the front vertical section, in the direction of unfolding of the section,
• a supporting linkage pivotally connected to the sections and constraining the latter to fold and unfold in accordance with a predetermined pattern of movement, that pattern involving the rear vertical section and lower horizontal section unfolding first after which the front vertical section and upper horizontal section unfold, when the sections move from their collapsed sofa condition to their extended bed condition, the supporting linkage including:
• a rear leg movable between a folded condition, when the sections are in the collapsed sofa condition, and an unfolded condition in which it supports the lower horizontal section, when the rear vertical and lower horizontal sections are unfolded,
• an upper horizontal section locking means for preventing unfolding movement of the upper horizontal section due to upward pressure of the folded mattress on the upper horizontal section, the unlocking movement of said locking means serving to initially further compress the folded mattress after which the upper horizontal section is permitted to unfold, said initial further compression to the folded mattress adding to the force required to unlock the upper horizontal section for unfolding movement, and
• means responsive to unfolding of the rear leg for relieving some of the pressure of the folded mattress on the upper horizontal section, so as to reduce the force necessary to initially unlock said locking means.