US Patent 7793809 Backpack frame

A backpack frame has a front side and a back side and comprises generally parallel base and top sections that extend transversely across and are spaces one from the other along a center line of the frame. Side rails connect the base section to the top section. The side rails are arranged on opposite sides of the frame center line, and a stabilizing rib interconnects the side rails and extends transversely across the center line at an intermediate location between the base and top sections. The side rails converge inwardly from the base section towards the frame center line to the stabilizing rib, and diverge outwardly from the stabilizing rib and away from the center line to the top section.