US Patent 6918848 Flexible broadhead arrow

The invention is a broadhead arrowhead. The broadhead arrowhead includes a ferrule, one end portion of which is tapered to a substantial point. One or more blade assemblies extend outwardly from the ferrule. Each blade assembly has a first substantially planar main surface portion disposed in a plane at least substantially parallel to a longitudinal axis of the ferrule and a second surface portion having a planar region offset at an angle to the plane of the main surface portion. A generally continuously curved region is disposed between and connecting the first and second portions, such that the blade assembly has an airfoil-type shape. Only the first planar portion of the blade assembly is coupled to the ferrule thereby allowing the second portion to flex during penetration of a target and achieve greater penetration depth.