Abstract: This application relates to an articulated sofa bed construction in which a bar is pivotally attached to the frame at the location where the knees of the user are located when the sofa bed is in bed defining position so that the bar can be raised beneath the mattress to form a knee supporting hump in the bed. The application also relates to a spring tie down construction to prevent the mattress supporting fabric from exerting undue pressure on the head section of the frame when it is in its raised head supporting reading position.