Patent ID: 7134155

Claim:
An adjustable bed for use on a substantially planar floor, the adjustable bed having: a main frame for supporting a mattress, the main frame having a first end and a second end; a scissor leg assembly for supporting the main frame; a motor mounted on the main frame and attached to the scissor leg assembly, for causing the scissor leg assembly to move between an extended condition, in which the main frame is in a fully raised position, and a retracted condition, in which the main frame is in a fully lowered position; the scissor leg assembly including: a first pair of legs having a proximal end slidably attached to the main frame at the first end and a second pair of legs having a proximal end pivotably attached to the main frame at the second end; a first caster base mounted at a distal end of the first pair of legs and positioned distal to the first end of the main frame, the first caster base including at least one first caster for engaging the floor; the first pair of legs being attached to the first caster base; the first caster base being disposed in a preselected position relative to the floor; a second caster base mounted at a distal end of the second pair of legs and positioned distal to the second end of the main frame, the second caster base including at least one second caster for engaging the floor; the second pair of legs being attached to the second caster base; the first and second pairs of legs being pivotably connected to each other at substantially coplanar central pivot points disposed substantially midway between the proximal ends and the distal ends of each said pairs of legs respectively, such that the scissor leg assembly is movable between the extended condition and the retracted condition; at least one first follower strut having an upper end and a lower end, the lower end being pivotably attached to the first caster base; the upper end of said at least one first follower strut being pivotably attached to at least one of said legs in said second pair of legs at a predetermined pivot point located between said central pivot point and the proximal end of said second pair of legs; and said at least one predetermined pivot point being selected such that said at least one first follower strut maintains the first caster base substantially in the preselected position relative to the floor as the scissor leg assembly moves between the extended condition and the retracted condition.