US Patent 7356864 Tubule featherbed

The featherbed includes upper and lower fabric layers, with the upper layer being longer than the lower layer. Lines of stitching connect the upper layer to the lower layer at spaced lateral lines along the length of the featherbed, thereby defining successive abutting lateral half-tubules, which are filled such that the upper layer extends away from the lower layer in a curved configuration, defining a plurality of half-tubules, generally in the shape of half-ellipses, with the fill density being greater, approximately 21% than that of a similar-sized conventional featherbed.