Abstract: A displaceable load carrying structure characterized by a main support arrangement (3), first and second sets (4, 5, 6, 7, & 8, 9, 10, 11) of support legs for supporting the main support arrangement (3) said support legs being vertically movable between raised and lowered positions relative to the main support arrangement, characterized in that each such set (4, 5, 6, 7, & 8, 9, 10, 11) of legs is capable of displacement as a set between said raised positions and said lowered positions and displaced relative to the other set while the legs of the other set (8, 9, 10, 11, or 4, 5, 6, 7) are in their lowered main support arrangement (3) supporting positions.