Abstract:
A sandal strap system for securing a foot of a wearer to a running sandal having a midsole assembly with a foot supporting surface. The sandal strap system includes a strap keeper attached to the midsole assembly and positioned adjacent to the foot supporting surface. An inner strap assembly includes a heel strap, an instep strap, and a forefoot strap, where the inner strap assembly is fixed to the midsole assembly. An adjustment strap attached to the heel strap extends through the strap keeper, and connects to an adjustment member, where the adjustment strap is adjustable at the adjustment member to simultaneously adjust the position of the heel strap, the instep strap, and the forefoot strap relative to the wearer&#39;s foot to tighten or loosen the strap system.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is a divisional of U.S. patent application Ser. No. 11/438,908, filed May 22, 2006, which is a divisional of U.S. patent application Ser. No. 10/644,126 (now U.S. Pat. No. 7,121,020), filed Aug. 20, 2003, which claims the benefit of U.S. Provisional Patent Application No. 60/404,707, filed Aug. 20, 2002, which are all herein incorporated by reference in their entirety. 
     
    
     TECHNICAL FIELD 
       [0002]    Embodiments of the present invention are directed toward footwear and more particularly toward sandal-style footwear. 
       BACKGROUND 
       [0003]    During sustained activity, such as walking, hiking and running, an individual&#39;s feet are subjected to large, repetitious ground reaction or impact forces generated in a gait cycle. A runner&#39;s foot experiences these ground reaction forces at various points during a typical gait cycle. The runner&#39;s gait cycle begins with the heel strike phase, where the initial ground contact at the lateral side of the heel takes place. The heel strike phase lasts until the rest of the foot or shoe contacts the ground, known as the flat foot phase. In the flat foot phase, the runner&#39;s weight rolls forward and inward onto the forefoot as the arch collapses, and moves onto the inner and front part of the forefoot where the foot is pushed off the ground and propelled forward. The flat foot phase lasts until the runner&#39;s heel lifts, thereby beginning the toe off phase. 
         [0004]    In the heel strike and the flat foot phases, the runner&#39;s foot typically pronates or supinates, and such pronation or supination will result in lateral movement of the runner&#39;s foot, ankle and lower leg. Conventional running shoes attempt to stabilize the runner&#39;s foot by providing a foot-encompassing supportive upper and a generally rigid heel cup shaped to snugly receive and control the runner&#39;s heel. However, shoes can be hot, especially during prolonged running in high temperatures. While sandals are open and much cooler, conventional open sandals do not have these same stabilizing mechanisms. 
         [0005]    It would be desirable to have an open sandal for running and other activities that can provide proper support and cushioning to dissipate impact forces, limit joint motion beyond the natural motion of the foot and preserve the natural forward motion associated with a wearer&#39;s natural gait. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS  
         [0006]      FIG. 1  is an isometric view of a sandal in accordance with an embodiment of the invention. 
           [0007]      FIG. 2  is a side elevation view of the sandal of  FIG. 1 . 
           [0008]      FIG. 3  is a bottom plan view of a midsole assembly of the sandal of  FIG. 1 . 
           [0009]      FIG. 4  is an isometric view of a disassembled midsole assembly of the sandal of  FIG. 1 . 
           [0010]      FIG. 5  is an enlarged bottom plan view of a curved forefoot plate of the sandal of  FIG. 1 ; the curved forefoot plate shown removed from the midsole assembly of the sandal. 
           [0011]      FIG. 6  is a side elevation view of the curved forefoot plate taken substantially along line  6 - 6  of  FIG. 5 . 
           [0012]      FIG. 7  is a bottom plan view of an outsole of the sandal of  FIG. 1 . 
           [0013]      FIG. 8  is a rear isometric view of a sandal upper in accordance with an alternate embodiment of the invention. 
       
    
    
     DETAILED DESCRIPTION  
       [0014]    In reference to the drawings in detail,  FIGS. 1 and 2  illustrate a sandal  10  in accordance with one embodiment of the present invention. The sandal  10  includes an upper  12 , a midsole assembly  14  (including various cushioning and support components) and an outsole  16 , together configured to provide the cushioning, stability, support and security provided by a running shoe in a lightweight and airy sandal package. A front portion  15  of the sandal  10  corresponds to a wearer&#39;s forefoot and toes (not shown), while a rear portion  17  of the sandal corresponds to a wearer&#39;s heel area (not shown) in the sandal  10 . 
         [0015]    The upper  12  is shaped and sized to receive and secure the wearer&#39;s foot (not shown). The upper  12  of the illustrated embodiment includes a plurality of fixed straps connected to the midsole assembly  14 , including front straps  24 , side lateral/medial straps  25  and a heel strap  26 . The upper  12  also includes a movable adjustment strap  18 . The adjustment strap  18  is configured in combination with the fixed straps ( 24 ,  25  and  26 ) to form a sandal strap system for comfortably securing the wearer&#39;s foot on the midsole assembly  14  during strenuous activities such as running or the like. 
         [0016]    In the embodiment illustrated in  FIGS. 1 and 2 , the adjustment strap  18  has two end portions  20 , each being looped around a center ring or adjustment member  22  fixed to one or more of the front straps  24  of the upper  12  and fastened back to a mid portion of the adjustment strap  18 . In the illustrated embodiment, a hook-and-loop material, such as Velcro™ is used to fasten the adjustment strap  18  to itself In alternate embodiments, fasteners such as snaps, hooks, clips, ties, buckles, etc. may be used. The adjustment strap  18  extends down both sides of the sandal upper  12  and around the heel strap  26 . On both the lateral and medial sides of the sandal, the adjustment strap  18  passes through midsole keepers  28  or loops secured to the midsole assembly  14 . The adjustment strap  18  is also secured at various points on the heel strap  26  and lateral/medial straps  25  by passing through various strap keepers  30  or other retention devices. 
         [0017]    When one or both of the end portions  20  of the adjustment strap  18  are pulled back and down toward the rear portion  17  of the sandal, the adjustment strap  18  slides through the adjustment member  22  to snugly secure the front straps  24  over the instep and forefoot area of the wearer&#39;s foot (not shown). The adjustment strap  18  also slides through the fixed keepers  30  and midsole keepers  28  of the sandal strap system, thereby pulling the heel strap  26  forwardly and securely against the heel portion of the wearer&#39;s foot. Accordingly, a single adjustment of the sandal&#39;s adjustment strap  18  secures the sandal&#39;s upper  12  around the forefoot and heel portion of the wearer&#39;s foot, anchoring the wearer&#39;s foot evenly and firmly into the sandal  10  so the wearer can experience a stable and secure feeling. In an alternate embodiment (not shown), the adjustment strap  18  may be securely fixed to the midsole assembly  14  and/or fixed straps ( 24 ,  25  and  26 ) at one or more points. In a second alternate embodiment, multiple adjustment straps may be configured to form a sandal strap system as shown in  FIG. 8  and described in more detail below. 
         [0018]    The adjustment strap  18  and fixed straps ( 24 ,  25  and  26 ) of the upper  12  securely hold the wearer&#39;s foot in place on a contoured footbed formed by the midsole assembly  14 . The midsole assembly  14  is positioned between the outsole  16  and the sandal upper  12  and may be fitted or sculpted with high sidewalls  32  for protection of the sides of the wearer&#39;s foot. In the illustrated embodiment, the outward facing portions of the sidewalls  32  are creased or grooved with a soft lateral release line  36  to promote the wearer&#39;s natural gait to the lateral side. For additional protection, a toe guard  33  extends from the front of the midsole assembly  14  to protect the toes of the wearer. In some embodiments, the toe guard  33  may not be provided, or may be removable. 
         [0019]    As best illustrated in  FIGS. 3 and 4 , the midsole assembly  14  includes a main body  35  shaped with various cavities to receive a plurality of components that provide stability and/or cushioning. In the illustrated embodiment, these components include a shock absorbing shock pad  42 , a plurality of energy-returning launch pads  44 , a stabilizer  38  and a curved forefoot plate  40 . 
         [0020]    The main body  35  of the midsole assembly  14  is constructed of a shock-absorbing material. While Phylon is used to construct the main body  35  of the midsole assembly  14  in the illustrated embodiment, other materials may be used, including materials such as ethylene vinyl acetate (EVA) foam, polyurethane foam or a combination of materials (e.g., a dual-density midsole). 
         [0021]    As shown in  FIGS. 3 and 4 , the shock pad  42  is received and retained in a cavity  43  integrally formed in the heel area of the main body  35  of the midsole assembly  14 . The shock pad  42  is positioned to be approximately under the heel of the wearer&#39;s foot (not shown). In the illustrated embodiment, the shock pad  42  has a generally trapezoidal shape that extends toward the front portion  15  of the sandal  10  from a slightly narrower rear side  45  to a slightly wider front side  47 . 
         [0022]    The shock pad  42  is made of a high-density foam material having very good energy absorption characteristics, so as to absorb and dissipate impact forces generated during the heel strike phase of the wearer&#39;s gait cycle. The shock pad  42  of the illustrated embodiment is constructed of polyurethane, although, in other embodiments, various other materials may be used to construct the shock pad  42 , such as EVA, rubber, brown rubber (resilient EVA), etc. 
         [0023]    The shock pad  42  is complimented by the energy returning launch pads  44  placed in the area of the midsole assembly  14  that approximately correspond with the metatarsals bones (not shown) of the wearer&#39;s foot. As best seen in  FIGS. 3 and 4 , the oblong-shaped launch pads  44  fit into cavities  49  in the main body  35  of the midsole assembly  14 . In the illustrated embodiment, two independent launch pads  44  are provided, one placed such that it approximately corresponds to the toes (not shown) of the wearer&#39;s foot and a second placed such that it approximately corresponds with the ball (not shown) of the wearer&#39;s foot when the sandal is worn. In an alternate embodiment (not shown), a single launch pad  44  is provided. In a second alternate embodiment (not shown) more than two launch pads  44  are provided. 
         [0024]    In the illustrated embodiment, the launch pads  44  are made of a high-density foam having very good energy absorptive characteristics as well as energy rebound characteristics to facilitate the conservation of reaction forces that propel the wearer&#39;s foot off the ground during the toe-off phase, as well as to provide some cushioning from initial ground impact. The foam may be constructed from materials such as polyurethane, EVA, rubber or brown rubber. 
         [0025]    The composition and placement of the launch pads  44  promote forward acceleration in the direction of the wearer&#39;s stride during the phase of the wearer&#39;s stride where the wearer&#39;s body weight shifts forward toward the forefoot and away from the heel, and during the toe-off phase. 
         [0026]    Along with cushioning features, the midsole assembly  14  may be fitted with various support features. As shown in  FIGS. 1 ,  2  and  4  the stabilizer  38  is positioned between the main body  35  of the midsole assembly  14  and the outsole  16  at a location generally corresponding to the arch area and midfoot area of the wearer&#39;s foot to provide support for the wearer&#39;s foot. The stabilizer  38  may be constructed of a semi-flexible material that allows for some fore and aft flexion while maintaining appropriate lateral support and support for the wearer&#39;s arch. For additional support, the midsole assembly  14  may be constructed with a firmer density material  34  ( FIG. 3 ) positioned at the arch area of the wearer&#39;s foot, providing arch support. These support features aid in the flow of the kinetic energy generated by the wearer&#39;s motion, allowing the wearer to maintain a flowing smooth stride while running. 
         [0027]    The midsole assembly  14  also includes the curved forefoot plate  40  that forms a longitudinal roll bar to further promote a flowing smooth stride, to help maintain the forward acceleration associated with the wearer&#39;s stride, and to avoid the bothersome toe slap, which is commonly experienced in prior art sandals. In the illustrated embodiment, the curved forefoot plate  40  is positioned at the bottom of the midsole assembly  14  covering an area that corresponds approximately with the forefoot of the wearer&#39;s foot when the sandal is worn. However, in an alternate embodiment (not shown) the curved forefoot plate  40  may be placed within or adjacent to the main body  35  of the midsole assembly  14 . The curved forefoot plate  40  is curved upward at both a front portion  45  and a rear portion  47  in a manner so as to allow for a fore and aft rolling action consistent with the wearer&#39;s natural gate. This curvature is best shown in  FIG. 6 , a lateral view of the curved forefoot plate  40  taken substantially along line  6 - 6  of  FIG. 5 . 
         [0028]    In the illustrated embodiment, the curved forefoot plate  40  is thin enough to fit between the main body  35  of the midsole assembly  14  and the outsole  16  without adding bulk at the front portion  15  of the sandal  10 . The curved forefoot plate  40  is otherwise shaped with curved exterior edges to conform approximately to the bottom front portion of the midsole assembly  14 . The curved forefoot plate  40  may be constructed of a material that is flexible enough to allow proper forefoot flexion, but yet structurally rigid enough to promote the natural rolling action associated with the wearer&#39;s gait. For example, materials such as TPU, hytrel, nylon, delrin, PVC and thermoplastic may be used. 
         [0029]    As best illustrated in  FIG. 5 , the curved forefoot plate  40  includes a raised or thickened center portion or stiffening rib  48 , extending from the center rear portion  47  of the curved forefoot plate  40  toward the center front portion  45  of the curved forefoot plate  40 . Similar stiffening ribs may be found on the outer side edges of the curved forefoot plate. The stiffening rib  48  is angled slightly toward the big-toe of the wearer&#39;s foot so as to align with the forces and direction of movement of the wearer&#39;s foot during the phase of the gate cycle where there is a natural tendency for the wearer&#39;s foot to pronate inward. An arrow  42  in  FIG. 5  depicts the typical direction of this inward movement. The stiffening rib  48  is thicker and acts to hold the main body  35  of the midsole assembly  14  in a curved shape. The portions of the curved forefoot plate  40  adjacent to the stiffening rib  48  are thinner so as to help control the over-all stiffness of the curved forefoot plate  40 . 
         [0030]    In the illustrated embodiment a concave flex groove  50  runs approximately laterally across the center of the curved forefoot plate  40 , oriented horizontally with respect to the front portion  45  and rear portion  47  of the curved forefoot plate  40 . The flex groove  50  adds targeted flexibility to the curved forefoot plate  40 , reducing some of the ground reaction force transmitted through the sandal  10  to the wearer&#39;s forefoot during the flat foot phase of the wearer&#39;s gait cycle and providing a smoother toe-off The curved forefoot plate  40  also includes side tabs  46  that allow it to be securely seated within an appropriately shaped cavity  51  ( FIGS. 3 and 4 ) in the main body of the midsole assembly  14 . 
         [0031]    The construction, placement and configuration of the curved forefoot plate  40  promotes a forward dynamic push-off in accordance with the phase of the wearer&#39;s gait cycle in which the wearer&#39;s foot rolls forward and inward as the arch collapses and moves onto the inner and front part of the forefoot where the foot is pushed off the ground and propelled forward. Additionally, by providing a firm rolling surface, the toe-slap that typically occurs with most sandals may be reduced. 
         [0032]    The dual-density outsole  16 , best illustrated in  FIG. 7 , is constructed to provide multidirectional grip and may be adhered to at least a portion of a bottom face of the midsole assembly  14 , covering the shock pad  42  and launch pads  44 , as well as portions of the stabilizer  38  and curved forefoot plate  40 . In the illustrated embodiment, the outsole  16  is bifurcated so that the flex groove  50  of the curved forefoot plate  40  remains exposed, allowing for appropriate flexibility and fore-aft rolling action. Outer portions of the stabilizer  38  also remain exposed. 
         [0033]      FIG. 8  illustrates an alternative embodiment of a sandal upper  12 . In this embodiment, the upper  12  includes a double sandal strap system  52  having a first adjustment strap  54  and a second adjustment strap  56 . Each of the two adjustment straps ( 54  and  56 ) is fixed to the adjustment member  22 . From the adjustment member  22 , the first adjustment strap  54  extends down the medial side of the sandal  10  and passes through the keeper  28  located on the lateral side of the midsole assembly  14  before extending up and back toward the heel strap  26 . Similarly, the second adjustment strap  56  extends from the center ring  22  down and back toward the lateral side of the sandal  10 , passing through the midsole keeper or loop  28  located on the lateral side of the midsole assembly  14  before extending up and back toward the heel strap  26 . 
         [0034]    At the rear portion  17  of the sandal  10 , the first adjustment strap  54  and the second adjustment strap  56  pass around the outside of the heel strap  26  and can be fastened to each other using a buckle assembly  58  or other similar fastening mechanism. In the illustrated embodiment, the first adjustment strap  54  is fixedly secured to its corresponding side of the buckle assembly  58 , while the second adjustment strap  56  is adjustably looped through a self-securing buckle keeper  60  and fastened back to itself such that the functional strap length of the second adjustment strap  56  can be easily altered and secured. In the illustrated embodiment, a hook-and-loop material (not visible) is used to fasten the end of second adjustment strap  56  back to itself so an excess end portion  62  of the second adjustment strap  56  does not flap. The hook-and-loop material may also prevent the second adjustment strap  56  from working its way loose through the buckle keeper  60  after being adjusted to a desired length. This configuration allows for easy and secure single strap adjustments. 
         [0035]    The second adjustment strap  56  can be adjusted by the wearer while the first adjustment strap  54  and the second adjustment strap  56  are separated from each other or connected via the buckle assembly  58 . When the second adjustment strap  56  is properly adjusted and the buckle assembly is fastened to connect the first adjustment strap to the second adjustment strap, the front straps  24  are secured over the instep and forefoot area of the wearer&#39;s foot (not shown) and the heel strap  26  is pulled forwardly and securely against the heel portion of the wearer&#39;s foot (not shown). In the illustrated embodiment, the heel strap  26  is attached to the lateral/medial straps  25  on only the lateral side, so that it does not bunch or buckle when the second adjustment strap  54  is tightened. 
         [0036]    From the foregoing, it will be appreciated that specific embodiments of the invention have been described herein for purposes of illustration, but that various modifications may be made without deviating from the spirit and scope of the invention.