Patent ID: 7644847

Claim:
A backpack frame comprising: side rails extending from a lower end to an upper edge of said frame, said side rails defining a first profile having a flat first base segment bordering said lower end and lying on a first reference plane, and having a first concave segment leading from said first base segment to and spanning the upper edge of said frame, said first concave segment being spaced a maximum distance from said first reference plane at a first location between said first base segment and the upper edge of said frame; and an intermediate structure interconnecting said side rails, said intermediate structure defining a second profile, said second profile having a second flat base segment bordering said lower end and lying on a second reference plane parallel to said first reference plane, and having a second concave segment leading from said second base segment to and spanning the upper edge of said frame, said second concave segment being spaced a maximum distance from said second reference plane at a second location between said second base segment and the upper edge of said frame; said second concave segment being arranged to overlap said first concave segment, with said first and second locations being offset from one another.