Sole for footwear or footwear attachment having multilevel cleats for indicating wear and providing enhanced traction and flexibility

A ground engaging portion of an article of footwear for enhancing the traction and flexibility of the ground engaging portion has a plurality of multilevel cleats. The multilevel cleats include a plurality of cleat base elements extending upwardly from a surface thereof to define a first level of the multilevel cleats. A plurality of cleat top elements extend upwardly from a surface of a selected cleat base element to define a second level. The cleat base elements are arranged upon the surface of the ground engaging portion to define both longitudinal and transverse base element grooves therebetween. The cleat top elements are disposed upon a cleat base element to define both longitudinal and transverse top element grooves therebetween.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now to various figures of the drawing where like reference numerals refer to like parts there is shown at 10 a ground engaging portion constructed in accordance with the invention. The ground engaging portion 10 is adapted for enhancing the traction and flexibility of articles of footwear such as the sole of an article of primary footwear, e.g., a shoe or a boot (shown in phantom in FIG. 3 ). The ground engaging portion 10 of the present invention can also enhance the traction and flexibility of an attachment device for mounting on an article of primary footwear ( FIG. 2 ), in order to render it more resistant to slippage on slippery surfaces. The attachment device is mounted to an article of primary footwear using straps as shown in FIG. 2 or in any other manner well understood by those skilled in the art. In accordance with the preferred embodiment of the invention the ground engaging portion 10 of either the article of primary footwear or the attachment device includes a plurality of multilevel gripping cleats 14 . The multilevel gripping cleats 14 are formed of any hard resilient material such as rubber or synthetic rubber and are adapted to improve the ground engaging traction-enhancing properties of the ground engaging portion 10 . The ground engaging portion 10 formed with multilevel gripping cleats 14 is adapted to provide enhanced traction and flexibility in all types of slippery conditions, including wet conditions and smooth ice. As best seen in FIG. 1 , each of the multilevel gripping cleats 14 includes a cleat base element 16 which extends upwardly from the surface of the ground engaging portion 10 to define a first level of the multilevel gripping cleats 14 . The cleat base elements 16 disposed upon the ground engaging portion 10 may be formed in any geometric shape or combination of geometric shapes. For example, the cleat base elements 16 can be formed as circles, squares or triangles. The arrangement of the cleat base elements 16 upon the surface of the ground engaging portion 10 is adapted to define both longitudinal base element flexing grooves 22 and transverse base element flexing grooves 24 between the adjacent rows and columns of the base elements 16 . The longitudinal base element flexing grooves 22 permit the article of footwear from which the base elements 16 extend to flex more easily along the entire lengths of the base element flexing grooves 22 . The easier flexing provided in this manner permits the user to be more comfortable when walking, while also permitting the user to obtain the benefits of a larger number of traction enhancing cleats which would otherwise cause the article of footwear to be more rigid. In a similar manner the flexing of the transverse base element flexing grooves 24 permits the article of primary footwear or attachment to flex more easily along their entire length. A portion of a longitudinal base element flexing groove 22 is defined between two transversely adjacent cleat base elements 16 . A further portion of the same longitudinal base element flexing groove 22 is defined between the next two transversely adjacent base elements 16 in either direction along the base element flexing groove 22 . In the preferred embodiment of the invention the two portions of the longitudinal base element groove 22 defined in this manner are aligned with each other. Because of the alignment in this embodiment the adjacent portions of the longitudinal base element flexing groove 22 can flex cooperatively as the user walks. The cooperation of the groove portions contributes to the flexibility of the article of primary footwear or attachment device upon which the base elements 16 are disposed and permits the use of a larger number of the multilevel cleats 14 and increased traction without causing excessive rigidity. Additionally, a portion of a transverse base element flexing groove 24 is defined between two longitudinally adjacent cleat base elements 16 . A further portion of the same transverse base element flexing groove 24 is defined between the next two longitudinally adjacent base elements 16 in either direction along the transverse flexing groove 24 . The two portions of the transverse base element flexing groove 24 defined in this manner are aligned with each other. Thus, in the preferred embodiment the two portions of the transverse base element flexing groove 24 defined in this manner can flex cooperatively as the user walks. The cooperation of the groove portions further contributes to the flexibility of the article of primary footwear or attachment device upon which the base elements 16 are disposed and permits the use of a larger number of multilevel cleats 14 and increased traction. It will be understood that a large number of such longitudinal and transverse aligned groove portions can be defined and can extend continuously over an entire longitudinal or transverse dimension of the ground engaging portion 10 . Plural top elements 28 extend upwardly from the top surface of at least one of the cleat base elements 16 . In the preferred embodiment of the invention plural top elements 28 extend upwardly from each cleat base element 16 . The top elements 28 disposed upon the base elements 16 may be formed in any geometric shape or combination of geometric shapes, e.g., circles, squares or triangles. As the ground engaging portion 10 is worn by a user the top elements 28 wear down. Thus, a user of the ground engaging portion 10 can view the length of the top elements 28 remaining upon the client base elements 16 to determine the amount of wear on the ground engaging portion 10 . It will be understood that as the length of the top elements 28 decreases due to a user wearing the ground engaging portion 10 , the amount of traction enhancement provided by the top elements 28 decreases accordingly. Thus, the user can view the remaining length of the top elements 28 , determine the usefulness of the ground engaging portion 10 upon which the top elements 28 are disposed, and replace the ground engaging portion when replacement is thus indicated. The arrangement of the top elements 28 is adapted to define both longitudinal top element flexing grooves 30 and transverse top element flexing grooves 32 between adjacent rows and columns of the top elements 28 . In the preferred embodiment of the invention the top element flexing grooves 30 , 32 extend from each multilevel cleat 14 to its adjacent multilevel cleats 14 along entire longitudinal and transverse dimensions of the ground engaging portion 10 . The top element flexing grooves 30 , 32 permit increased flexibility of the base elements 16 of the multilevel cleats 14 and, hence, increased flexibility of the ground engaging surface upon which the multilevel cleats 14 are disposed. Thus, a greater number of top elements 28 can be disposed on the base elements 16 without excessively increasing the rigidity of the base elements 16 , thereby increasing traction while permitting the article of primary footwear or attachment device to be more comfortable for a user when the user is walking. In accordance with the invention, any number of top elements 28 can be disposed upon an individual base element 16 provided that the top elements 28 are arranged to form the top element flexing grooves 30 , 32 . A portion of a longitudinal top element flexing groove 30 is defined between two transversely adjacent top elements 28 . A further portion of the same longitudinal top element flexing groove 30 is defined between the next two transversely adjacent top elements 28 . In the preferred embodiment of the invention these portions of the longitudinal base element groove 30 are aligned with each other. Thus, in this embodiment the two adjacent portions of the longitudinal top element flexing groove 30 can flex cooperatively as the user walks. Cooperation of the groove portions in this manner contributes to the flexibility of the base elements 16 and, hence, to the flexibility of the article of primary footwear or attachment device upon which the base elements 16 are disposed. Furthermore, a portion of a transverse top element flexing groove 32 is defined between two longitudinally adjacent top elements 28 . A further portion of the same transverse top element flexing groove 32 is defined by the next longitudinally adjacent top elements 28 . Thus, in this embodiment the two adjacent portions of the transverse top element flexing groove 32 can flex cooperatively as the user walks. This also contributes to the flexibility of the article of primary footwear or attachment device as previously described. It will be understood that the adjacent cooperating portions of the top element flexing grooves 30 , 32 defined in this manner can be disposed upon a single base element 16 or upon adjacent base elements 16 . As should be appreciated from the foregoing description the ground engaging portion 10 having the multilevel gripping cleats 14 in accordance with the invention is simple in construction and can be fabricated readily. Moreover, when the ground engaging portion 10 is provided as an attachment device for an article of primary footwear and molded of a resilient material it can be folded or rolled up into a compact configuration. Thus, it can be conveniently stored or transported until the user is ready to wear it. For example, a worker can carry the attachment device either unfolded or folded, unrolled or rolled in his/her pocket. When it is desired to use the attachment device, it can be conveniently retrieved and mounted upon the article of primary footwear. Without further elaboration the foregoing will so fully illustrate our invention that others may, by applying current or future knowledge, adapt the same for use under various conditions of service.