Patent Publication Number: US-10757997-B2

Title: Sandal

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application claims priority to the U.S. patent application Ser. No. 13/103,746 titled “SANDAL” filed on May 9, 2011. 
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
     Not Applicable. 
     REFERENCE TO A “SEQUENCE LISTING,” A TABLE, OR A COMPUTER PROGRAM 
     Not Applicable. 
    
    
     
       DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a depiction of one embodiment of the sandal from a perspective view—the left sandal is shown. 
         FIG. 2  is a side view of one embodiment of the left sandal. The view is from the inside of the sandal, also known as the medial side, looking to the wearer&#39;s left. 
         FIG. 3  is a top view of one embodiment of the left sandal. This view shows one embodiment of the medial split feature in cutaway. 
         FIG. 4  is a side view of one embodiment of the left sandal. The view is from the inside, or medial side, of the sandal looking to the wearer&#39;s left. This view also shows the apertures for the strap attachment points in cutaway. 
         FIG. 5  is a front view of one embodiment of the left sandal. The view is from the inside, or medial side, of the sandal looking to the wearer&#39;s left. 
         FIG. 6  is a depiction of one embodiment of the left sandal from another perspective view. This view also shows the strap attachment apertures and medial split in cutaway view. 
         FIG. 7  is a perspective view of the one embodiment of the left sandal that shows the strap. 
         FIG. 8  is an additional perspective view of one embodiment of the left sandal that shows the strap. 
         FIG. 9  is a view of one embodiment of the sole bottom that includes a swirl tread design. 
     
    
    
     DETAILED DESCRIPTION 
     An improved sandal with several orthotic benefits is described herein. It is believed that the sandal can be used for the treatment and prevention of plantar fasciitis. As depicted in  FIG. 1 , the sandal has sole  1 . Sole  1  will include big toe rise  6 , medial split  7 , upward bend  8  and metatarsal bar  9 . All the figures show that upward bend  8  and metatarsal bar  9  are contiguous, integrated components. 
     As shown in  FIG. 2 , sole  1  has rocker bottom  10 . When the wearer is in a neutral position, only the center of sole  1  will be in contact with the ground surface. The elevations in the front and back sections of rocker bottom  10  will be slightly off the floor. As shown in  FIG. 3 , the sandal will have a shape that is generally in the broad outline of an anatomically correct foot. The anatomically correct foot includes slight medial angulation of the hind foot and slight adduction of the mid and forefoot. The overall design of the rocker bottom sole is designed to be sharp enough to decrease tension on the plantar fascia, but shallow enough to allow only gentle balance motions to promote massage of the fascia and strengthening of the intrinsic muscles of the foot as well as the dynamic stabilizing muscles of the ankle. 
     Big toe rise  6  is designed so that the wearer&#39;s big toe is higher than the other toes. The wearer&#39;s other toes rest on lateral toe bed  11  which is lower than big toe rise  6 . Big toe rise  6  is sized so as to lift the wearer&#39;s big toe higher than the remaining toes. Big toe rise  6  begins approximately at metatarsophalangeal (MTP) joint point  24  of sole  1 . MTP joint point  24  approximately coincides with the wearer&#39;s first MTP joint of the big toe. In one preferred embodiment, big toe rise  6  will rise up from MTP joint point  24  going toward the front of sole  1  at an angle of approximately 5 to 20 degrees. As shown in  FIGS. 1 and 3 , in one preferred embodiment, toe slope  12  will connect lateral toe bed  11  and big toe rise  6  to provide greater comfort for the wearer. In an additional preferred embodiment, big toe rise  6  begins just at the level of the sesamoid bones and provides a cushion for these bones. In an additional preferred embodiment the angulation of the big toe rise will be approximately 15 to 20 degrees. 
     It is believed that toe rise  6  will promote the windlass mechanism of the plantar fascia. The windlass mechanism describes how the plantar fascia is pulled taut during the wearer&#39;s gait. The windlass mechanism is caused by the dorsiflexion of the first MTP joint during the phase of gait known as “toe-off.” The toe-off phase occurs as the body moves over the planted foot. The foot moves in a slightly rotational way, spinning from the fifth metatarsal head, along the ball of the foot, to the first MTP joint. At that point in the gait cycle, the MTP joint flexes and the plantar fascia pulls taught. The heel is tipped into varus and the posterior tibial muscle fires. This initiates heel rise, then the achilles mechanism allows for push-off. Plantar fasciitis is caused by an imbalance at any point of this complex relationship during the gait cycle. This problem is often exacerbated by those with varus hindfeet, stiff first MTP joints and neutral to cavus midfeet. The improved sandal is designed to accommodate the biomechanical forces that promote and exacerbate plantar fasciitis. By assisting in forward roll with a rocker-bottom, using tread design to accommodate the lateral to medial spin during gait, cushioning the origin of the plantar fascia with the medial split and assisting the windlass mechanism with the toe rise, the sandal described herein will allow for improvement in the symptoms of plantar fasciitis. 
     The gait cycle begins with heel strike. Historically, it was thought that the hindfoot struck the ground in a position of eversion. However it is more likely that the heel strikes in slight varus and quickly moves to eversion as the foot moves to foot-flat during gait. Sole  1  has a slight lateral to medial curve with rises on each side and contact being more centralized at the heel. This shape of sole  1  will assist the wearer in this natural motion. As the heel strikes in varus, the lateral portion of the hindfoot sole will easily accommodate this force. As the heel moves to eversion the medial portion of the posterior sole will allow for lesser impact on the calcaneus and plantar fascia. Medial split  7  is limited to the posterior medial aspect of the heel in order to allow for enough support during gait. Medial split  7  allows for a slightly less amount of energy to be absorbed by the calcaneus in the region of the plantar fascia insertion. Often, in plantar fasciitis, this region of bone has stress changes consistent with “bone bruising.” Medial split  7  and the overall design of the sandal aim to lessen the pain associated with this type of bone bruising. 
     With reference to all the figures, medial split  7  will now be described in greater detail. Medial split  7  is a void or cut out section of sole  1 . The location of medial split is at the back of sole  1 , behind upward bend  8  and metatarsal bar  9 . Medial split  7  is designed so that when the wearer initially strikes heel  13  against the ground surface, the wearer&#39;s weight will be equally supported medially and laterally. However, as the wearer&#39;s weight on heel  13  is increased, medial split  7  will compress more than the lateral section of heel  13 . The compression effect will absorb energy from the medial portion of the heel while still providing some suspension for the medial heel strike. The purpose of this feature is to promote a lateral to medial rotation of the heel portion and reduce wearer heel pain. 
     In the embodiment shown, medial split takes up approximately 25% of the length of sole  1  and 50% of the width of sole  1  at heel  13 . In a preferred embodiment, medial split extends forward from heel  13  and terminates at the mid-arch section  15  of sole  1 . It is believed that medial split  7  can perform its desired functions described above if it takes between 20% and 30% of the length of sole  1  and 30% to 50% of the width of sole  1 . 
     All the figures except  FIG. 5  show that in one embodiment, medial split  7  can be constructed by a void in sole  1  that is then partially filled by columns  11 . Material for columns  11  is chosen so that medial split  7  will compress more than the surrounding sections of sole  1  during the gait of the wearer. 
     The remainder of sole  11  is constructed of conventional materials used in sandal construction. Those skilled in the art will know that the sole can be constructed in a single layer using ethylene vinyl acetate (EVA), polyurethane surrounding another material such as gel or liquid silicone, or polyurethane foam. In some cases, those skilled can construct sole  1  in layers, including but not limited to a top layer, midsole, and outsole. If layers are used, the insole is typically a thin layer of EVA. The midsole, which is usually the thickest layer, consists of polyurethane surrounding another material such as gel or liquid silicone, or polyurethane foam. Outsoles are usually made of some type of rubber. Those skilled in the art may also choose to use cork or wood as materials, or any material which may be fashioned using injection molding or three-dimensional sculpting with Computer Aided Design (CAD) devices. It will be obvious to those skilled in the art to use a variety of such materials for the sole  1 , and this invention is not intended to be limited to any particular materials used in sole  1 . 
     While in the embodiment depicted, medial split  7  is a void partially filled with columns, medial split  7  could also be designed in other ways to create the same results during the wearer&#39;s gait. Medial split  7  could be a void only, in which case the material immediately adjacent the void would need to have greater density and flexion resistance so as to allow some compression but also some medial support through the wearer&#39;s heel strike and gait. Medial split  7  could also be constructed by using material that is less dense in this section of the sole. Medial split  7  could also be constructed by a void that is partially occupied by structures other than columns  11 . For example, the void could be partially occupied by honeycomb structures or by parallel wall structures oriented in any direction. 
     As shown in the embodiment in  FIG. 9 , sole  11  can include a tread pattern with a ball and swirl design. This tread pattern will promote the lateral to medial spin of the wearer&#39;s foot during the gait. Those skilled in the art will be familiar with variations of the ball and swirl tread design that will perform the desired function. 
     Metatarsal bar  9  serves to support the transverse arch. The transverse arch of the foot is the arch that runs along the mediolateral axis of the foot. As shown in  FIG. 5 , bar mid-section  16  is higher than bar lateral section  17 . As the upwardly curved shape of metatarsal bar  9  supports the transverse arch, it is believed that this shape will help to prevent collapse of the middle foot as the windlass mechanism is activated. 
     The medial longitudinal arch, that is usually associated with the concept of ‘arch’ in the foot, is also supported in terms of function by the transverse arch. The transverse arch is formed at the bony level by the association of the cuneiforms as they articulate with the metatarsals. The apex of this arch is at the position of the 2nd metatarsal bone. If the transverse arch is accommodated and there is less stress on the keystone position of this arch, there is less stress on the medial longitudinal arch. The improved sandal, with its strong structural transverse arch, will reduce the force required by the posterior tibial muscle, the main dynamic stabilizer of the foot. Therefore, most of this muscle and tendon unit&#39;s force will go toward stabilizing the apex of the medial longitudinal arch. This reduces the stress on either end of the tie-rod of that arch. Arches have forces at each inferior point with compression of the apex of the arch. The vector of force is typically away from these points as the apex depresses with load. A tie-rod connects the two bottom points of the arch. As the arch depresses, and therefore widens, these ends of the tie-rod must handle the tension applied. In the foot, the ends of the tie-rod at the origin of the plantar fascia and the first metatarsophlangeal joint. The improved sandal design will promote a reduction in the tension applied at the point of origin of the plantar fascia and thereby decrease pain. 
     As shown in the figures, metatarsal bar  9  is partially integrated with gently sloped upward bend  8 . Upward bend  8  begins to rise from sole  1  at a point just forward of the terminus of medial split  7  and reaches its highest point at its intersection with metatarsal bar  9 . Upward bend  8  then slopes downward again, terminating at sole  1  at a point slightly behind big toe rise  6 . Upward bend  8  also serves to support the arch during the activation of the windlass mechanism. 
     As shown in  FIGS. 5, 7, and 8 , the sandal will include strap  2 . Strap  2  includes strap junction  17 , anterior segment  18 , medial segment  19 , and lateral segment  20 . Anterior segment  18  extends from strap junction  17  to anterior attachment point  21 . Preferably anterior attachment point  21  is located on sole  1  at a point in or proximate to big toe rise  6 . Medial segment  19  extends from strap junction  21  to medial attachment point  22 . Preferably medial attachment point  22  is located on sole  1  at a point in or immediately forward of medial split  7 . In one preferred embodiment, medial section  19  originates from the front edge of medial split  7 . Lateral segment  20  extends from strap junction  21  to lateral attachment point  23 . Preferably lateral attachment point  23  is located on sole  1  at a point near the medial edge of sole  1  but at a point on the long axis of sole  1  that is approximately even with medial attachment point  22 . 
     In one preferred embodiment, strap  17  is constructed so that its segments have varying densities. Specifically, the density and stiffness of medial segment  19  and lateral segment  20  are greater than the density and stiffness for strap junction  17  and anterior segment  18 . It is believed that having relatively greater stiffness and density in medial segment  19  and lateral segment  20  will keep metatarsal bar  9  and upward bend  8  engaged with the transverse arch of the wearer during the wearer&#39;s gait. 
     The combination of the elements will provide therapeutic effects for those wearers who suffer from plantar fasciitis and preventative effects for those who do not. The rocker sole  10  with a gentle medial to lateral rise also present in the hindfoot again allows for reduced tension on the tie-rod or the medial longitudinal arch, or plantar fascia, during gait. As the foot moves from heel-strike to foot-flat to toe-off, the improved sandal provides a biomechanical assistive portion at each moment designed to reduce the stress on the plantar fascia and yet allow efficient gait. It is believed that the combination of all of these biomechanical elements in this design will allow for a reduction in plantar fascia pain for those suffering this debilitating disease. The treatment of plantar fasciitis by this improved sandal a far more cost effective treatment for this problem than any invasive treatments now available. 
     Any and all references to patents, documents, and other writings contained herein shall not be construed as an admission as to their status with respect to being or not being prior art. 
     The described features, advantages, and characteristics may be combined in any suitable manner in one or more embodiments. One skilled in the relevant art will recognize that the various components of this design may be practiced without one or more of the specific features or advantages of a particular embodiment. In other instances, additional features and advantages may be recognized in certain embodiments that may not be present in all embodiments. 
     Reference throughout this specification to “one embodiment”, “an embodiment”, or similar language means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment. Thus the appearance of the phrase “in one embodiment”, “in an embodiment”, and similar language throughout this specification may, but do not necessarily, all refer to the same embodiment. 
     The invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The present embodiments are therefore considered in all respects as illustrative and not restrictive. Accordingly, the scope of the invention is established by the appended claims rather than the foregoing description. All changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein. 
     Moreover, the terms “substantially” or “approximately” as used herein may be applied to modify any quantitative representation that could permissibly vary without resulting in a change to the basic function to which it is related. 
     PARTS LIST 
     
         
         sole  1   
         strap  2   
         front strap  3   
         medial strap  4   
         lateral strap  5   
         big toe rise  6   
         medial split  7   
         upward bend  8   
         metatarsal bar  9   
         rocker bottom  10   
         lateral toe bed  11   
         toe slope  12   
         heel  13   
         columns  14   
         mid-arch section  15   
         bar midsection  16   
         strap junction  17   
         anterior segment  18   
         medial segment  19   
         lateral segment  20   
         anterior attachment point 
         medial attachment point  22   
         lateral attachment point  23   
         MTP joint point  24