Abstract:
A shoe sole structure includes a midsole body that extends from the heel region to the forefoot region of a shoe and an outsole that is attached to the midsole body. The outsole includes a plurality of protrusions arranged transversely to the longitudinal axis of the shoe, while extending at least partially between the lateral edge and the medial edge of the shoe. One or more of the half tube structures can include grooves and/or projections to enhance traction on a contact surface.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims priority to U.S. application Ser. No. 12/117,824, filed May 9, 2008, and U.S. Provisional Application Ser. No. 60/931,513, filed May 22, 2007. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates to sport or athletic shoes. According to an example, the shoes are constructed to minimize impact shock and to increase stability and support. 
     2. Description of the Related Art 
     In most types of footwear, especially athletic shoes, the lower or underfoot portion of the shoe includes a midsole, which is directly attached to the shoe upper portion. An outsole is attached to the midsole and is generally designed to resist wear and provide traction. The midsole is designed primarily to provide stability for the foot while attenuating shock. 
     When running and walking, generally the foot makes initial contact with the ground surface on the lateral portion of the rearfoot area. At initial contact, runners typically strike the ground at a force of 2.5 times their body weight, which may be repeated at a rate of 180 times per minute (90 per each foot). Therefore, the heel strike cushioning material, which is contained mostly in the midsole of a running or walking shoe must have a firmness to provide for proper impact cushioning. If the midsole material is too soft, the material will “bottom out” before heel impact is completely absorbed, and shock-related injuries could result. Softer midsoles also offer poor lateral stability that can also result in injuries. 
     The modern athletic shoe is a combination of elements, which cooperatively interact in an effort to minimize weight and maximize comfort, cushioning, stability and durability. However, these goals are potentially in conflict with each other and in an effort to achieve one of these objectives, a deleterious effect on one or more of the other goals can occur. 
     The cushioning in most athletic shoes is supplied through the foam midsole that can be made from either ethylene vinyl acetate (EVA) or polyurethane. These materials provide ample cushioning when they are new, but lose some of the cushioning ability over time due to failure of the structured materials by the application of shear and vertical forces applied to them. 
     A shoe industry trend has been toward thickening the midsoles of athletic shoes to enhance the cushioning effect of the sole. An added thickness of foam, however, can cause the sole to have increased stiffness in bending. Under these conditions, the lateral corner of the sole can tend to operate as a fulcrum upon heel strike and create an extended lever arm and greater moment, which can cause the foot to rotate medially and pronate with greater velocity than desired. This can lead to over-pronation of the foot and possible injury. Further, this condition can present a potentially unstable condition for the foot and result in the transmission of higher than desired levels of impact stress due to the relatively small surface area of contact. 
     SUMMARY OF THE INVENTION 
     According to an aspect of the invention, it has been recognized that prior shoe designs suffer from one or more disadvantages including: a midsole that is too soft so as to provide poor lateral support and not completely absorb an impact, and thicker midsoles that can result in over-pronation of the foot and possible injury. 
     The present invention relates to improved shoes that address the competing concerns of cushioning and stability with the ground support phase of running and walking in both the heel strike area and the forefoot area. 
     According to an example, the invention pertains to athletic footwear used for running and walking. More specifically, an example pertains to athletic shoe constructions designed to attenuate applied force and shock, and to provide support and stability during running and walking. 
     In one example, the invention utilizes the outsole of a shoe to provide increased shock absorption upon impact, while transitioning into stability and support during running and walking. 
     A shoe according to another example of the invention provides improved shock absorption upon heel strike without relying on soft midsoles to obtain the needed shock absorption during both the initial heel impact and the forefoot impact during running and walking. 
     In one example, the athletic footwear includes an upper, a midsole attached to the upper, and a sole attached to the midsole. According to an improvement, the sole of the shoe includes one or more protrusions extending transversely to the longitudinal axis of the shoe. As an example, the protrusions can be in the shape of a half tube and can extend across the width of the sole. 
     In one preferred embodiment, the rear sole incorporates one or more slots or grooves along at least part of the length of at least one of the half tube tread members. For example, the slots could be located in front of and behind the intended heel strike area of the half tube tread member. These slots reduce the wall thickness of the half tube tread member, allowing for more flex or compression of the half tube tread member to provide shock absorption. As an example, one or more tube members could have one or more grooves that extend different lengths across the length of the tube member. 
     In an alternative embodiment, each half tube tread member can be provided with projections, for example raised cleats, instead of or in addition to grooves, to increase the wall thickness in selected areas and to provide traction and durability. 
     As an example of the invention, each half tube tread member can have a different wall thickness. The difference in wall thickness can be based on which area of the foot is in contact with the ground surface. In an example, the wall thickness of the half tube tread members in the rear lateral portion is thicker than the center of the rear portion to allow more flex or bending of the half tube after initial contact. That is, as the foot makes contact with the ground, one or more of the half tube tread members begin to collapse or bend upward, absorbing shock of the impact upon landing on a firm surface. 
     In a further example, each of one or more tube members can vary in thickness in the longitudinal direction of the shoe. For example, a tube member could have a thicker wall thickness at the beginning and/or ending of the tube member than a portion of the tube member near a middle of the tube member. 
     As a further example, one or more tube members can vary in thickness along the length of the tube member. Embodiments of the present invention have a plurality of half tube shaped tread members adjacent to each other and extending transversely between the lateral side edge to the medial side edge of the midsole. In one preferred embodiment, the lateral side of the outsole has thinner walls than the medial side so that upon contact, more shock absorption is available. 
     According to an example, the half tube tread members include approximately one half of the circumference of a tube. 
     According to an example, the shoe midsole includes cavities that extend from the lateral side of midsole to the medial side. Each cavity receives a portion of the outsole formed between adjacent half tube tread members. 
     As should be apparent, the invention can provide a number of advantageous features and benefits. It is to be understood that in practicing the invention, an embodiment can be constructed to include one or more features or benefits of embodiments disclosed herein, but not others. Accordingly, it is to be understood that the preferred embodiments discussed herein are provided as examples and are not be construed as limiting, particularly since embodiments can be formed to practice the invention that do not include each of the features of the disclosed examples. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention will be better understood from reading the description which follows and from examining the accompanying figures. These are provided solely as non-limiting examples of the invention. In the drawings: 
         FIG. 1  is a side view of the lateral side of an athletic shoe according to an example of the invention; 
         FIG. 2  is an elevation view of the lateral side of an athletic shoe according to an example of the invention; 
         FIG. 3  is a bottom view of the under side of an athletic shoe according to an example of the invention. 
         FIG. 4  is an elevation view of the lateral side of an athletic shoe according to an example of the invention prior to the outsole being attached; 
         FIG. 5  is a top plan view of the outsole of the athletic shoe shown in  FIG. 1 ; 
         FIG. 6   a  is a top view of the half tube tread members shown in  FIG. 1 ; 
         FIG. 6   b  is a top view of the half tube tread members shown in  FIG. 1 ; 
         FIG. 7   a  is a top view of a half tube member of an example of the invention; and 
         FIG. 7   b  is a cross sectional view a half tube member showing different wall thicknesses according to an example of the invention. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Reference will now be made in detail to the present preferred embodiments of the invention, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference characters will be used throughout the drawings to refer to the same or like parts. 
       FIG. 1  is a side view of an athletic shoe  10  according to one example of the present invention. An upper portion  11  of athletic shoe  10  is typically fabricated from for example, stitched fabric, leather, canvas or other types of synthetic materials. The upper portion  11  also includes a midsole portion  12  that is attached to upper portion  11  and can be made from for example, a foam or soft rubber type material. Attached to the midsole  12  of the athletic shoe  10  is an outsole  13 . 
     According to embodiments of the invention, the outsole  13  can include a plurality of protrusions  14 . The protrusions  14  can be in the shape of a half tube. For example, the half tube tread members  14  incorporate an approximately 180 degree configuration. That is, the half tubes include approximately one half of the circumference of a tube. A further example provides for a configuration of the half tube that satisfies a condition within the range of 150 degrees to 190 degrees. 
     It should be appreciated that the protrusion of one or more examples of the invention can be any desirable shape. The half tube tread member  14  can be made from a flexible material, such as rubber or urethane. The half tube tread members  14  on outsole  13  can be provided immediately adjacent each other or can be spaced apart as discussed with respect to  FIG. 5 . 
       FIG. 2  shows a medial view of an athletic shoe  10  according to an example of the present invention. When the athletic shoe  10  comes in contact with a firm surface, half tube tread members  14 , which can have a curved exterior ground contacting surface, are provided on outsole  13  and will deflect or compress  16  upon impact to absorb shock. As discussed further below, the amount of deflection or compression on half tube tread member  14  can be derived from the firmness of the material used on outsole  13  and/or the wall thickness of half tube tread member  14 . 
       FIG. 3  is a lateral tilt view of athletic shoe  10  showing outsole  13  with multiple half tube tread members  14  adjacent to each other and extending from the rear of athletic shoe  10  to the front of the athletic shoe. In this embodiment, the tube members  14  are positioned substantially transverse to the longitudinal direction of the shoe and extend from the outer lateral portion of outsole  13  to the inner medial portion of outsole  13 . It should be appreciated that each tube member  14  can extend a different distance across the width of the shoe, for example, completely or partially across the width. Further, as shown in  FIG. 3 , a gap  19  between the tube members of the heel portion and tube members of the forefoot portion is provided. However, examples of the invention include tube members  14  that are provided along the entire length of the outsole  13 . 
     In one preferred embodiment, each half tube tread member  14  has one or more grooves  15  to allow for traction on different types of surfaces. As shown from  FIG. 3 , the grooves  15  can extend the length of the tube members, that is, extend from the lateral side of the tube member to the medial side of the tube member or the grooves can extend only a portion of the length of the tube member. In an example, a single tube member could have some grooves  15  that extend the entire length and other grooves  15  that extend only part of the length of the tube member. Further, the grooves  15  can be formed at any location along the half tube tread members. It should be appreciated that the grooves can have a different depths than other grooves  15  formed on the same tube member. Further, grooves  15  of one tube member  14  can have different depths than grooves  15  formed in other tube members  14 . Even further, examples of the invention provide for the grooves  15  to extend on one or more tube members  14  in the longitudinal direction of the shoe. 
       FIG. 4  is a lateral view of athletic shoe  10  with only the upper  11  and midsole  12  attached to each other. An example of the invention provides for multiple cavities  17  in the midsole  12  that extend from the lateral side of midsole  12  to the medial side of the midsole. Each cavity  17  can receive a securing portion  18  of outsole  13  to secure the outsole  13  to the remainder of the shoe  10 . It should be appreciated that the cavities  17  are optional and the securing portion  18  of the outsole  13  can be secured directly to the midsole using for example an adhesive, stitching, or molded together instead of being received in the cavities  17 . The securing portion  18  can be a substantially flat area formed between each half tube tread member  14 . That is, the area between half tube members  14  can be a connecting portion from one half tube member to another half tube tread member and also can be a securing portion to connect the outsole  13  to the remainder of the shoe  10 . The securing portion  18  can extend in a widthwise direction of the shoe. 
       FIG. 5  shows a top view of outsole  13  with multiple half tube tread members  14  connected to each other by the securing portion  18 , which connects into cavities  17  on midsole  12  as discussed above with respect to  FIG. 4 . Therefore, in one embodiment of the invention, outsole  13  has a plurality of half tube tread members  14  each formed with grooves  15  extending at least partially from one side of half tube tread member  14  to the opposite side. When securing portion  18  is bonded to the midsole  12  either within cavities  17  or directly to midsole  12 , a shoe is provided with enhanced stability and support upon impact due to the half tube tread members  14 . 
       FIG. 6   a  is a cross sectional view of a half tube tread member  14 . In one preferred embodiment, each half tube tread member  14  includes a plurality of grooves  15  which extend lengthwise to provide traction on a firm surface. It should be appreciated that the grooves  15  can extend differing lengths across the length of the half tube  14 . In the example shown in  FIG. 6   a , a center groove  15  extends completely across the length of the tube member  14 , while the grooves on either side of the center groove  15  only extend partially across the length of the tube member  14 . Each groove  15  on half tube tread member  14  effectively reduces the wall thickness  21  of each half tube tread member  14 , which can allow for increased deflection or compression upon impact. 
     In an alternate embodiment shown in  FIG. 6   b , one or more of the half tube tread members  14  can have one or more projections  19  extending from the surface of the tube member. The projections  19  can be, for example, raised cleats that provide traction and durability on a firm surface. The one or more projections  19  can be provided instead of or in addition to the grooves  15  formed on the surface of the half tube members  14 . 
     The amount of shock absorption each individual half tube tread member provides can be determined by either the softness of the material or the wall thickness of each half tube tread member.  FIG. 7   b  is a cross sectional view of half tube tread member  14  at section A-A of  FIG. 7   a . In an example of the invention, one or more of the half tube tread members  14  can have a variable wall thickness in the lengthwise direction (A 1 -A 1 ) and/or the widthwise direction (A-A) of the tube member  14 . In one embodiment shown in  FIG. 7   b , half tube tread member  14  has a larger wall thickness  21  at the ends or sides which will reduce in thickness towards the top or middle portion wall thickness  20 . For example, one or more half tube tread members  14  can have a thicker wall thickness  21  formed along the edges of the tread members, which is tapered to a thinner wall thickness  20  towards a middle. Providing the thickness according to this example allows for more deflection or compression upon initial contact with a firm surface. 
     Further, in one preferred embodiment, the lateral side of one or more tube members  14  have thinner walls than the medial side so that upon contact with a ground surface during use, more shock absorption is available. As the foot starts the rolling motion during running or walking, the sole tends to firm up as it rotates towards the medial side to prevent over pronation. As a further example of the invention, one or more half tube members  14  can have one or both of the end portions thicker than a middle portion along the length of the tube member  14 . For example, the thickness can vary along the direction from a lateral to medial side or vice versa. 
     One or more embodiments of the present invention do not need to rely on softer or thicker midsole foams to provide adequate shock absorption and support. The mechanical compressing and flexing of the half tube tread members provides increased shock absorption that can evolve into support and stability as the half tube tread members transition from a thin wall to a thicker wall. Accordingly, one or more examples of the present invention allows for the use of a thinner and stiffer midsole material for less loss of energy during running and walking. 
     Obviously, numerous modifications and variations of the present invention are possible in light of the above teachings. It is therefore to be understood that within the scope of the appended claims, the invention may be practiced otherwise than as specifically described herein.