Flexible and stiff wall extension for an open load hauling box on a truck

A method of increasing the volumetric capacity of an open load hauling box on a truck comprising the steps of:

• a) providing a rectangular frame above, and dimensioned to seat adjacent to an open top side portion of the load hauling box on the truck;
• b) providing a lift mechanism wherein the lift mechanism comprises hinged links, said links having one end portion hinged to one of the frame and the top side portion of the truck box, and each link having an opposite end portion slidingly disposed within a track on the other of the frame and the top side portion of the truck box, so that when the slidingly disposed end portion of the link is drawn to an upright position the frame is lifted to uniformly lift the rectangular frame above the box;
• c) wherein a longer side portion of the rectangular frame is centrally lifted and there are four spaced links along each opposite longer side portion of the rectangular frame, and the slidingly disposed end portions of the front and rear inner links are respectively connected together, so that when the slidingly disposed portions of the two inner links move a specified distance raising a central portion of the frame a specific height, the slidingly disposed portions of the two outer links move similar distances raising an outer portion of the frame a corresponding height;
• and,
• d) providing and attaching an elongate strip of fabric having a top elongate side portion peripherally attached to the rectangular frame, and a bottom elongate side portion peripherally attached to the open top side portion of the box;
• so that when the rectangular frame is uniformly lifted therearound to an upper operable position, the fabric is uniformly stretched taut therearound and is thereby able to sustain significant lateral load.