Abstract:
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.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    This application relates generally to footwear and more particularly to a ground engaging portion of an article of primary footwear such as a shoe or a boot, or an attachment device which is adapted to be mounted upon an article of primary footwear so that the ground engaging portion provides enhanced traction between the article of primary footwear and a walking surface and substantial flexibility.  
           [0002]    It is well known in the art to provide a sole having cleats disposed upon its ground engaging portion in order to enhance traction between the sole and a walking surface. Additionally, various attachment devices for primary footwear having cleats disposed upon their ground engaging portions are available for enhancing traction between the primary footwear and a walking surface. Attachment devices bearing spikes are also available to prevent slippage on ice or other slippery surfaces. The known attachment devices can take the form of complex sandals or other devices which are adapted to be mounted upon an article of primary footwear by means of attaching straps or components for engaging the upper of the footwear. Additionally, the attachment devices can take the form of simple pads or strips for securement to the sole of the primary footwear.  
           [0003]    Examples of these devices are found in U.S. Pat. Nos. 1,032,600 (Grout); 2,361,972 (Smith); 3,214,850 (McNair); 3,516,181 (Jordan); 4,344,238 (Peyser); 4,353,172 (Bryant); 4,525,939 (McNeil et al.); and 4,910,883 (Zock, Jr.). Further examples are found in U.S. Pat. Nos. 1,796,399 (Roodhouse); 1,747,603 (Ruth); 1,716,790 (Mitchell); 2,426,524 (Rosenbarger); 2,408,152 (Porcelli); 2,732,065 (Marchese); 2,793,136 (Root); 3,561,140 (Ludwig); 3,903,620 (Gillet); 4,702,021 (Cameron); and 4,924,608 (Mogonye). U.S. Pat. No. 4,271,610 (Parrent) discloses a pad for releasable securement to an article of footwear for adjusting friction. Additionally, copending U.S. patent application Ser. No. 09/378,251 discloses an attachment device having strips of elastic material that form a toe box section and a heel counter section for releasably mounting the attachment device to an article of primary footwear. A ground engaging traction enhancing surface has contoured recessed areas shaped to receive and retain a plurality of hard non-elastic cleats. The attachment device is detachably mounted on an article of primary footwear using straps.  
           [0004]    While the aforementioned prior art devices are generally suitable for their intended purposes, they still leave something to be desired from various standpoints. For example, a common method of increasing the traction provided by the prior art soles and attachment devices is to increase the number of cleats disposed on the ground engaging portion thereof and thereby provide additional gripping points to apply to the walking surface. However, increasing the number of cleats in this manner also increases the rigidity of the ground engaging portion. Increased rigidity due to the presence of a larger number of cleats makes the sole or the attachment device uncomfortable for the user when the user is walking.  
           [0005]    It is known to arrange the cleats on a ground engaging surface in a manner adapted to thereby contribute less rigidity to the ground engaging portion and make the sole or attachment device less uncomfortable for the user. Ground engaging surfaces of this type are shown in the following U.S. Pat. Nos. 767,120 (Pratt), 997,657 (Drake), 1,011,110 (Brown), 1,490,107 (Hale), 2,303,682 (Bullis), 4,194,310 (Bowerman), 4,899,467 (Mackey), 5,282,288 (Henson), 5,293,701 (Sullivan) and 6,101,746 (Evans). These references disclose a plurality of arrangements of cleats on such ground engaging surfaces including arrangements forming flexible grooves for permitting greater flexibility of the surfaces.  
           [0006]    Other prior art attachment devices for footwear are shown in the following U.S. Pat. Nos. 157,985 (Buxton), 913,411 (Marius), 1,299,037 (Runyan), 1,299,650 (Young), 1,433,902 (Masters), 1,518,910 (Gammeter), 1,587,571 (Willis), 1,601,700 (Morrison), 1,716,790 (Mitchell), 1,747,603 (Ruth), 1,877,080 (Teshima), 1,970,254 (Sullivan), 2,076,316 (Beals, Jr.), 2,275,214 (Alvistur), 2,303,744 (Jacobs), 2,327,360 (Margolin), 2,350,362 (Margolin), 2,370,963 (Issaly), 2,387,029 (Kellman), 2,423,753 (Brooks), 2,617,209 (Jackson), 2,628,437 (Forsythe), 3,012,343 (Dinkel), 3,040,451 (Helkemeyer), 3,583,082 (Jordan, Jr.), 3,609,888 (Rickman), 4,302,890 (Covell et al.), 4,727,662 (IIon), 4,807,372 (McCall), 4,924,608 (Mongonye), 5,341,582 (Liautand), 5,485,687 (Rohde), 5,752,332 (Kataoka) and 6,018,889 (Friton). All of the aforementioned ground engaging surfaces also suffer from one or more drawbacks.  
         OBJECTS OF THE INVENTION  
         [0007]    Accordingly, it is a general object of the invention to provide a ground engaging portion for use on an article of primary footwear, e.g., a boot, shoe, etc., or an attachment device for an article of primary footwear which overcomes the disadvantages of the prior art.  
           [0008]    It is another object of the invention to provide an article of primary footwear or an attachment device for an article of primary footwear for enhancing the traction provided by the ground engaging surface thereof.  
           [0009]    It is yet another object of the invention to provide an article of primary footwear or an attachment device for an article of primary footwear for enhancing the traction of the article of footwear which is simple in construction.  
           [0010]    It is another object of the invention to provide an article of primary footwear or an attachment device for an article of primary footwear including a ground engaging surface having plural cleats or spikes for providing increased traction.  
           [0011]    It is another object of the invention to provide an article of primary footwear or an attachment device for an article of primary footwear having substantial depth recesses or grooves formed therein for providing a traction enhancing, ground engaging surface.  
           [0012]    It is another object of the invention to provide an article of primary footwear or an attachment device for an article of primary footwear having substantial depth recesses or grooves formed therein arranged for providing substantial flexibility of the primary footwear or attachment device.  
           [0013]    It is another object of the invention to provide an article of primary footwear or an attachment device for an article of primary footwear having wear indicating elements for indicating when the ground engaging surface is worn down due to use and requires replacement.  
         SUMMARY OF THE INVENTION  
         [0014]    These and other objects of the subject invention are achieved by providing a ground engaging portion for a sole or an attachment device for an article of primary footwear, the ground engaging portion having a plurality of multilevel cleats. Generally, the multilevel cleats include a raised base element thereby defining a first level of the multilevel cleat. Plural additional top elements are disposed upon the base element thereby defining a second level of the multilevel cleat. The base elements are disposed on the ground engaging surface in spaced apart locations selected to define both longitudinal base flexing grooves and transverse base flexing grooves therebetween. The longitudinal and transverse base flexing grooves disposed between the base elements are adapted to enhance the flexibility of the ground engaging surface. Furthermore, the top elements are disposed in spaced apart locations upon the surfaces of the base elements selected to define both longitudinal top element flexing grooves and transverse top element flexing grooves therebetween. The longitudinal and transverse top element flexing grooves are adapted to further enhance the flexibility of the ground engaging surface by permitting the base elements to be move flexible. Thus, the invention set forth herein is a ground engaging portion of an article of footwear having longitudinal and transverse axes for enhancing the traction and flexibility of the ground engaging portion, the ground engaging portion having a plurality of multilevel cleats. The multilevel cleats of the plurality of multilevel cleats include a plurality of cleat base elements extending upwardly from a surface of the ground engaging portion and defining a first level of the multilevel cleats and a plurality of cleat top elements extending upwardly from a surface of a selected cleat base element and defining a second level of the multilevel cleats. The cleat base elements are disposed in a spaced apart arrangement upon the surface of the ground engaging portion to define between said spaced apart cleat base elements both a longitudinal base element groove along the longitudinal axis and a transverse base element groove along the transverse axis. The cleat top elements are disposed in a spaced apart arrangement upon a surface of the selected cleat base element to define both a longitudinal top element groove and a transverse top element groove between the cleat top elements. The ground engaging portion is an article of primary footwear or an attachment device for mounting the attachment device upon an article of primary footwear. Two, four or any other number of top elements can extend upwardly from the surface of the cleat base element provided that the longitudinal and transverse flexing grooves are defined therebetween. The surface of the ground engaging portion, the cleat base portions, and the cleat top portions are formed from a resilient material as an integral unit. At least one of the cleat base elements or the cleat top elements is formed in a square, circular, triangular, or any other shape. 
       
    
    
     DESCRIPTION OF THE DRAWINGS  
       [0015]    Other objects and many attendant features of this invention will become readily appreciated as the same become better understood by reference to the following detailed description when considered in connection with the accompanying drawing wherein:  
         [0016]    [0016]FIG. 1 is an isometric view of the multilevel cleats of the subject invention disposed upon a ground engaging surface of an article of primary footwear or an attachment to an article of primary footwear;  
         [0017]    [0017]FIG. 2 is a plan view of an attachment device in accordance with the subject invention for mounting upon a conventional article of primary footwear; and  
         [0018]    [0018]FIG. 3 is a plan view of a sole of a shoe in accordance with the invention (the shoe being shown by phantom lines). 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0019]    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.  
         [0020]    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.  
         [0021]    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.  
         [0022]    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.  
         [0023]    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.  
         [0024]    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 .  
         [0025]    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 .  
         [0026]    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.  
         [0027]    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 .  
         [0028]    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 .  
         [0029]    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.  
         [0030]    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 .  
         [0031]    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.  
         [0032]    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.