Abstract: A footwear structure including an upper and a separate midsole having interlocking shank portions. The upper has an upward extending arc in the shank area which defines a shank interlock portion therein. The midsole has a corresponding arc which defines a shank interlock portion on a bottom surface thereof which mates with the arc in the upper for resisting motion of the midsole relative to the outsole in the case where the midsole is unsecured within the structure to allow for removal of the midsole. The structure may include an outsole having a shank interlock area that mates with the shank interlock of the midsole, with or without an upper disposed between the midsole and the outsole. The shank interlock areas may include a continuous arc or an abruptly changing arc, and the midsole may be removable or non-removable from the structure. A rigid shank insert may be provided between the midsole and outsole, and the midsole may include a variety of layers.

Abstract: A footwear structure including an upper and a separate midsole having interlocking shank portions. The upper has an upward extending arc in the shank area which defines a shank interlock portion therein. The midsole has a corresponding arc which defines a shank interlock portion on a bottom surface thereof which mates with the arc in the upper for resisting motion of the midsole relative to the outsole in the case where the midsole is unsecured within the structure to allow for removal of the midsole. The structure may include an outsole having a shank interlock area that mates with the shank interlock of the midsole, with or without an upper disposed between the midsole and the outsole. The shank interlock areas may include a continuous arc or an abruptly changing arc, and the midsole may be removable or non-removable from the structure. A rigid shank insert may be provided between the midsole and outsole, and the midsole may include a variety of layers.