Patent Application
20070017123
It is well known to selectively stiffen the sole of footwear by placing a stiffer insert in a portion of the midsole. Doing this provides stability, allows the midsole to bend at the desired location and allows the remainder of the midsole to be made more flexible and cushioning than it otherwise could be. A common material used for such an insert is metal. However, prior art inserts do little to provide tortional stability since tortional movement of the foot is generally above the top of the midsole. In addition, if the insert is metal the portion of the midsole containing the insert is substantially not flexible at all. Finally, if the insert is metal, it activates airport metal dectors if the user forgets to remove the footwear before passing through them.
The subject invention provides a midsole insert having medial and lateral portions which extend upwardly from a center portion which provides both longitudinal and tortional stability in the midsole it is placed into.
The foregoing and other objectives, features, and advantages of the invention will be more readily understood upon consideration of the following detailed description of the invention, taken in conjunction with the accompanying drawings.
Referring now to the drawings, a shoe 10 has a midsole 12, an outsole 14 and an upper 16 which are all joined together in the conventional fashion. An inner sole 18 is inserted inside of the shoe above the midsole,
Located in the cavity 20 is an insert 30. The insert 30 has a center portion 32 which fills the portion of the cavity located in the upper surface 22 of the midsole. Thus, the insert causes no significant discontinuity in the upper surface of the midsole. Located at the inside edge of the center portion 32 is a medial portion 34. The medial portion extends upwardly from the center portion and fills the portion of the cavity 20 located in the inside edge of the midsole. Located at the outside edge of the center portion 32 is a lateral portion 36. The lateral portion extends upwardly from the center portion and fills the portion of the cavity 20 located in the outside edge of the midsole. The medial and lateral portions of the insert extend above the outsole and overlay the outside surface of the upper 16. In addition, the outsole 14 extends downwardly at the medial and lateral portions of the insert exposing even more of them. For aesthetic reasons the upper edges of the medial and lateral portions of the insert and the downwardly extending portions of the outsole are curved. The insert is made from a material which is stiffer than the midsole material. In a preferred embodiment, the insole is made from a combination of EVA and cork rubber. This combination gives a cork appearance to the material which results in the exposed portions of the medial and lateral portions also being a design element.
The insert 30 provides additional stiffness to the midsole 22 at the location where additional stiffness is required, essentially under the ball of the foot. As a result, the rest of the midsole can be more flexible and have greater cushioning than otherwise would be possible. However, unlike metal inserts, the use of an EVA/cork insert still allows some flexibility along the entire extent of the midsole. Moreover, due to the fact that the front edge of the insert extends diagonally across the midsole, the midsole flexes approximately at the base of the toes, rather than at the arch. In addition, by not having a metal insert, footwear utilizing the subject midsole do not trigger airport metal detectors.
By having the insert extend upwardly along both sides of the midsole, it also provides tortional stability. This prevents the foot from rolling side-to-side while walking which causes discomfort and can cause ankle injury. In addition, it tends to reduce over pronation or supination of the wearer's feet.
Finally, by making the insert from a cork material and extending the medial and lateral portions 34, 36 above the outer sole 14 onto the upper 16 where they are exposed, the inserts provide an aesthetically pleasing design feature.
The terms and expressions which have been employed in the foregoing specification are used therein as terms of description and not of limitation, and there is no intention, in the use of such terms and expressions, of excluding equivalents of the features shown and described or portions thereof, it being recognized that the scope of the invention is defined and limited only by the claims which follow.
