Abstract:
A coupling device molded into a shoe sole for allowing a user to detachably couple a shoe upper to the shoe sole. The coupling device includes a socket with a set of ratchet teeth that are movable between an unbiased position and biased position by touching a button. The coupling device also includes a prong that can be inserted into the socket and has a plurality of complementary ratchet that can engage with the ratchet teeth of the socket.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This application claims priority to provisional Application No. 61/504,584 filed Jul. 5, 2011 and titled “Improved Coupling Device and Method for Making a Molded Shoe,” which is hereby incorporated by reference in its entirety. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The invention relates to an apparatus for footwear. More specifically, the apparatus relates to footwear having a device associated with a sole and a detachable upper shoe part that allows a user to exchange shoe uppers and shoes soles at will. 
       BACKGROUND 
       [0003]    In slipper-type footwear of the type comprising a molded sole and an upper part, particularly although not exclusively lady shoes, it is desirable to have a variety of shoe uppers which can be exchanged onto a sole at will, for instance to match colors and patterns of attire for a particular occasion. 
         [0004]    U.S. Pat. No. 5,896,684 issued on 27 Apr. 1999 to Lin, discloses a simple shoe such as a sandal or slipper having detachable toe and ankle straps. Each strap has at least a pair of mounting strips, each having a serrated plug strip, that fasten to a corresponding pair of locating members in the sole of the shoe. The locating members have a serrated constraing tongue that engages the serrated plug strips to secure the uppers to the sole. A pin-like tool is manipulated by the user for disengaging the serrated plug strip from the contstraint tongue to detach the show upper from the sole. A housing means in provided in the show upper for keeping the tool at hand. 
         [0005]    The need for a tool to detach the shoe upper from the sole represents several disadvantages in practice. Maneuverings and wedging a tool in between the plug strip and the tongue is unappealing to most ladies. Furthermore, although housing means are provided for the tool, it could get lost. Again, many ladies do not enjoy tinkering about with a tool box to look for a suitable replacement, such as a screw-driver, especially after they are dressed up and have decided that they prefer a different shoe color or pattern to match a particular dress, purse, hat, etc. 
       SUMMARY 
       [0006]    In view of the foregoing, an object of the invention is to provide a coupling device comprising elements affixed to the sole and shoe upper of a shoe to enable a user to fasten the shoe upper to the sole, and to easily detach the shoe upper from the sole without requiring a separate tool. The shoe upper can be detached with hardly any force, such as by a lady or a young child, yet the coupling device resists unwillful detachment under extreme walking, jogging, jumping and climbing conditions, whatever the terrain. The shoe can have any design or type, such as a slipper or sandal, ranging from leisure to evening dress. Certain aspects of the invention provide a coupling device for use in detachably coupling a shoe upper to a sole to enable a user to assemble and disassemble the shoe at will, the sole having a body having a foot-bearing topside bounded by at least on lateral side, the coupling device comprising: a socket, embeddable in the sole, the socket comprising: (i) an inner wall, an outer wall and two connecting side walls, forming a shaft passage having a slotted opening penetrable through a foot-bearing topside of the sole; (ii) a tongue comprising a plurality of ratchet teeth, the tongue being resiliently movable from an unbiased engaged position and a biased disengage position; and (iii) a button, depressible by a finger of the user, the button having a first rest position and a second depressed position, the button being in direct communication with the tongue whereby when the button is in its rest position, the tongue is in its unbiased engaged position, and when the button is in the depressed position, the tongue is in its biased disengaged position; and (b) a plug having a generally flat body and comprising: (i) an upper portion affixable to the shoe upper; and (ii) at least one prong insertable into the shaft passage through the slotted opening, the prong comprising a plurality of complementary ratcheted teeth of the tongue in its unbiased engaged position upon insertion of the plug into the shaft passage, thereby coupling the plug to the socket; whereby when the button is depressed to its depressed position, the tongue moves to the biased disengaged position, whereupon the ratcheted teeth of the tongue disengage from the ratcheted teeth of prong, and thereby the plug is uncoupled from the socket 
         [0007]    Certain aspects of the invention provide a coupling device configured for to be molded into a shoe sole for detachably coupling a shoe upper to enable a user to assemble and disassemble the shoe at will, the coupling device comprising a socket, the socket having a shaft passage there through and comprising a tongue disposed in the shaft and having a plurality of ratchet teeth movable from an unbiased engaged position and a biased disengaged position in response to depression of a button affixed to the tongue, where the button extends through a opening in the socket, and a plug having an upper portion affixable to the shoe upper; and at least one prong insertable into the socket and having a plurality of complementary ratcheted teeth that detachably engage with the ratcheted teeth of the tongue in its unbiased engaged position upon insertion of the plug into the socket, and a socket enclosure configured to surround the socket and button and to prevent flowable resin from entering the socket and the air space surrounding the button during molding of the sole. 
         [0008]    Certain aspects of the invention also provide a footwear manufacturing method, utilizing the coupling device of the invention, to incorporate more and new designs, functional lines and shoetrees with versatility and economy. The invention includes a method for manufacturing a socket, for embedding in the sole of a shoe and receiving for insertion therein a removable plug for coupling a detachable shoe upper to the sole to enable a user to assemble and disassemble the shoe at will. The method comprises: (a) molding integrally the socket walls, base, tongue and button into a single piece, wherein the base is molded as a flat sheet having a first base portion forming an open bottom end of the socket shaft passage, a thin hinge portion along one side of the first portion, and a second base portion joined by the hinge portion to the first portion; and a frangible membrane affixed to the button and the outer wall to temporarily seal off the in the outer socket wall; (b) folding the second base portion back under the first base portion to form the base of the socket shaft passage, thereby forming an assembled socket; (c) molding the assembled socket into a resin-based shoe sole using a flowable resin; and (d) depressing the button, thereby breaking the frangible membrane. The method further preferably comprises the step of placing a cap over the assembled socket, the cap having an outer resilient wall enclosing an air space surrounding the button, thereby preventing flowable resin from entering the air space during molding of the sole. 
         [0009]    Certain aspects of the invention provide a method for manufacturing footwear, the method comprising: (a) providing a socket having a shaft passage there through and comprising a tongue disposed in the shaft passage and having a plurality of ratchet teeth movable from an unbiased engaged position and a biased disengaged position in response to depression of a button affixed to the tongue, where the button extends through a opening in the socket, and a plug having an upper portion affixable to the shoe upper; and at least one prong insertable into the socket and having a plurality of complementary ratcheted teeth that detachably engage with the ratcheted teeth of the tongue in its unbiased engaged position upon insertion of the plug into the socket; (b) providing a socket enclosure configured to surround a lower portion of the socket and the button, (c) affixing the socket enclosure to the socket, thereby covering the opening to the shaft passage ‘and the enclosing the air space surrounding the button, (d) molding the socket into a resin-based shoe sole using a flowable resin, wherein the flowable resin is prevented from entering the socket and the air space surrounding the button. 
         [0010]    Certain aspects of the invention provide a method where a plurality of plugs are attached to a shoe upper, the plug having a generally flat body and comprising: (i) an upper portion affixed to the shoe upper; and (ii) at least one prong insertable into the shaft passage through the slotted opening, the prong comprising a plurality of complementary ratcheted teeth that detachably engage with the ratcheted teeth of the tongue in its unbiased engaged position upon insertion of the plug into the shaft passage, thereby coupling the plug to the socket, and thereby attaching the shoe upper to the sole. 
         [0011]    The invention also provides a shoe that is adaptable to an array of exchangeable shoe uppers. 
         [0012]    Certain aspects of the invention provide a two-part coupling device that is hardly visible to observers of a lady wearing the shoe, yet is simple for her to access. 
         [0013]    Certain aspects of the invention further provide a method for molding a shoe sole comprising a shoe upper attachment/detachment socket. 
         [0014]    These and other objects, aspects, and advantages of the present invention will be better appreciated in view of the following detailed description of preferred embodiments. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0015]      FIG. 1  is a perspective view of a sole and a detached shoe upper than can be assembled into a shoe by means of two or more coupling denies of the present invention consisting of sockets  11  and plugs  15 . 
           [0016]      FIG. 2  is a plan view of a socket embedded in the shoe sole showing a partial cut-away of the sole. 
           [0017]      FIG. 3  is an elevation view of a two-pronged plug. 
           [0018]      FIG. 4  is an enlarged cross-sectional view through lines  4 - 4  of  FIG. 3 . 
           [0019]      FIG. 5  is a perspective view partially cut away of a coupling device in an uncoupled position. 
           [0020]      FIG. 6  is a cross-sectional view of the coupling device of  FIG. 5  through line  6 - 6 , shown in a coupled position. 
           [0021]      FIG. 7  is a cross-sectional view of the coupling device of  FIG. 5  taken through line  6 - 6 , shown in the uncoupled position, with the button depressed and with the plug withdrawn. 
           [0022]      FIG. 8A  is a plan view of a one-piece socket for a coupling device of the invention.  FIG. 8B  is a cross-sectional view of the one-piece socket of  FIG. 8A  through line  8 B- 8 B. 
           [0023]      FIG. 9  is a partial view of the cross-sectional view of the socket of  FIG. 8B , with the button depressed and showing a breached socket sidewall. 
           [0024]      FIG. 10  is a perspective view of a cap used with another coupling device of the invention. 
           [0025]      FIG. 11  is a cross-sectional view of the socket of  FIG. 8A  with the cap of  FIG. 10 , when viewed through sectional line  11 - 11  of  FIG. 9 . 
           [0026]      FIG. 12  is a perspective view of another embodiment of a socket and an enclosure cap. 
           [0027]      FIG. 13  is a cross-sectional view of the socket of  FIG. 12  with the affixed enclosure cap. 
           [0028]      FIG. 14  is a plan view of the socket shown in  FIG. 12  through line  13 - 13 , embedded in a shoe sole, showing a partial cut-away of the sole. 
           [0029]      FIG. 15  is a perspective view of a set of molds for making a shoe sole incorporating the coupling devices. 
           [0030]      FIG. 16  is an illustration of an original push button for the upper. 
           [0031]      FIG. 17  is an illustration of a push button for the upper with a stopper. 
       
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
       [0032]    In the Summary above and in the Detailed Description of Preferred Embodiments, reference is made to particular features (including method steps) of the invention. It is to be understood that the disclosure of the invention in this specification includes all possible combinations of such particular features. For example, where a particular feature is disclosed in the context of a particular aspect or embodiment of the invention, that feature can also be used, to the extent possible, in combination with and/or in the context of other particular aspects and embodiments of the invention, and in the invention generally. 
         [0033]    As used herein, “upper” (when used as a noun) or “shoe upper” refers to an upper part of a shoe or other footwear, and can include a toecap part, a toecap patch, or an open-toe strap that covers the forward part of the foot of a user, can include ankle and heel straps, and can include unitary and integral combinations thereof. 
         [0034]    As used herein, “horizontal” refers to a normal shoe position, i.e. with the sole resting on a horizontal surface. As used herein, “outer” and “inner” refer to elements of the coupling device positioned nearer and further away, respectively, from the nearest lateral side of the sole. 
         [0035]    A coupling device, according to an embodiment of the invention comprises two parts: a socket and a plug. The socket is typically embedded into a shoe sole, while the plug is typically affixed to the shoe upper. However, the socket can be affixed to one of the sole and shoe upper, while the plug can be affixed to the other of the sole and shoe upper. 
         [0036]    The socket includes a plurality of sidewalls that form a shaft passage that is adapted to receive the plug, a toothed tongue for engaging and latching to the plug, and an integral release means for releasing the tongue from the plug, whereby the shoe upper can be detached from the sole. The tongue is resiliently connected at a first end to at least one of the inner wall or the outer wall, and is preferably resiliently connected at an upper end by a resilient bridge to the inner wall proximate the slotted opening. The tongue comprises an upper portion and a lower portion having a surface facing the outer wall, the surface preferably having two toothed surfaces, each comprising the plurality of ratcheted teeth, astride a middle portion. 
         [0037]    Each plug and socket part can be separately advantageously manufactured in one piece. Alternatively, the devices can be made in two or more parts. For example, the socket can comprise a separate button that can be secured to the socket, for the movement within the outer wall of the socket. 
         [0038]    In a preferred embodiment, the plug has two spaced-apart toothed prongs, and the tongue has an end resiliently affixed to a sidewall of the socket. The integral release means, preferably a button, extends through an orifice in the socket toward a nearest sidewall of the sole. The button communicates with the tongue by a stem joined to the button, the stem traversing the outer wall and connecting to a lower portion of the tongue. Within the socket, the button preferably passes between the pair of toothed prongs, and is integrally attached to the tongue, preferably to the middle, lower portion of the tongue, to communicate the finger pressure applied to the button. The applied pressure on the button displaces the tongue away from the plug sufficiently to separate the respective engaged teeth of the tongue and the prongs, thereby disengaging and releasing the plug. 
         [0039]    Preferably the button is positioned within the sole in close proximity to the lateral outer wall  9 , as shown in  FIG. 2 . The sole can have a raised mark  19  in lateral sidewall indicating the position of the button positioned proximately thereto. Alternatively, the button may barely project from the flush surface of the sidewall of the sole. 
         [0040]    The button is preferably positioned to go generally unnoticed by a casual observer, yet is easily manipulated simply by pressing with a finger, without use of tools. In a method of manufacture as put, the shaft passage of the socket is sealed to keep it free from mold resin during molding of the sole body into which it is incorporated. The method comprises providing a socket body having a fold-over base that can cover the socket opening. Preferably, the socket has a frangible membrane that closes off the socket space inside from the button housing. Preferably, the button has a base end joined to the stem, the outer wall has an inner-facing surface, and the membrane joins the button base end and the inner surface of the outer wall. The thin membrane temporarily seals off the orifice in the outer wall to prevent flowable resin from entering the socket during molding of the sole. The frangible membrane can be breached or broken after the socket has been molded into the sole, by simply pressing the button, thereby making the coupling device operational. 
         [0041]    In a preferred embodiment, the socket is enclosed around its sidewalls by a cap prior to placing the socket inside the molded sole. The cap maintains an air gap in the space around the button. The cap serves to keep the injected molding resin out from around the button, and provides a projecting surface outward from and engageable with the button to facilitate access to the button by a user. Although the cap obviates the need for the membrane as a barrier to molding resin, the membrane is preferably also used since it helps to withstand inward depression of the button under the injection pressures of the molding resin. 
         [0042]    Construction and Operation:  FIG. 1  shows a first embodiment of the invention of a shoe, such as a lady&#39;s high-heeled slipper, comprising a sole  1  molded from a resin and a shoe upper  3 . The shoe sole  1  has a top or foot-bearing surface  5 , and a lateral outer wall  9 . Six sockets  11 , forming part of a like number of coupling devices, are embedded in the body of the sole  1 . A like number of plugs  15  are attached to the bottom edge  7  of the shoe upper  3 . Each socket  1  comprises a tongue  33  to engage with its corresponding plug  15 . The tongue  33  is associated with a button  45  positioned proximate to the later outer wall  9  of the sole. 
         [0043]      FIG. 2  shows a plan view of the socket  11  positioned in the top surface  5  of the sole  1 . The socket  11  has a shaft passage  27  and a slot-shaped opening  13  level with the top surface  5  that can receive a corresponding plug  15 . The socket shaft passage  27  is generally oriented parallel to the nearest lateral side  9  of the sole  1 . The tongue  33  communicates with the button  45  via short stem  47  that traverses an orifice  41  (see  FIG. 8B ) in the outer wall  43  of the socket. The rounded button  45  is positioned proximate the later outer wall  9 , as shown by the cut-away portion of the sole of  FIG. 2 . The button  45  is preferably positioned adjacent to the outer wall  9  of the sole whereby a hump mark  19 , formed from the sole resin material covering the button  45 , identifies the position of the button  45  to allow a user to locate and depress the button with a finger while being generally unnoticeable. 
         [0044]      FIG. 3  shows a plug  15 . The plug  15  is molded as a substantially flat piece from a suitable, generally stiff material selected from materials including but not limited to plastics, metal, and rubber. Preferably, the plug  15  has a top portion  17  that is affixed to the edge  7  of the shoe upper  3  by any suitable means, such as stitching or adhesive. The top portion  17  is preferably trapezoidal, measuring about 20.5 mm across the top, 11 mm down and about 1.1 mm thick. 
         [0045]    A pair of prongs  21  depends from the top portion  17 , leaving a rectangular cut-out portion  23  between the prongs. Preferably, each prong  21  is about 13 mm long and 8 mm across, and has an inner face ratcheted with a plurality of ratchet teeth  25  that have a 1 mm pitch.  FIG. 4  is a sectional view of a prong that shows the shape of the teeth  25 . The thickness of each prong is preferably about 2.10 mm at its widest portion and 1.34 mm at its thinner portion. The teeth  25  are shaped in a typical saw-tooth configuration such that a first edge of each tooth  25  is generally perpendicular to the direction of movement of the prong  21  during insertion into the socket opening  13  for properly latching into the socket with the teeth of the tongue. The adjacent second edge of each tooth  25  is at an angle of about 30 degrees to said direction of movement, to facilitate insertion. 
         [0046]    As illustrated in  FIGS. 5 and 6 , the socket  11  comprises a prism body having an outer wall  43 , an inner wall  35 , and connecting walls which enclose a shaft passage  27 , and an integral laminar base  29 . The sidewalls and the base are fixed within the sole  1 . The base  29  closes off the bottom of the shaft passage  27  of the socket  11 . The base  29  is preferably provided with holes  31 A and cut-outs  31 B for better anchoring of the socket  11  into the resin of the sole. 
         [0047]    A tongue  33  has a top edge attached to the inner wall  35  by a relatively thin resilient hinge portion  37  that enables the tongue member  33  to sway or pivot in an arch toward and away from the inner wall  35 . As shown in  FIG. 6 , the outward-facing surface of the tongue  33  has a plurality of vertically spaced ratchet teeth  39  that are sawtoothed shaped and are dimensioned to mesh with the plug teeth  25  when the plug  15  is inserted in the socket  11 . Short flat valleys  26 , as shown in  FIG. 4 , positioned between each tooth  25  of the prong  21  and tooth  39  of the tongue  33 , ensure proper engagement even when the prong  21  is not inserted perfectly straight into the socket  11 , and preserve the sharp edges of the teeth from breaking off. For a 1.0 mm spacing between the teeth, the flat valley  26  can be about 0.3 mm, or 30% of the spacing. 
         [0048]    A shot stem  47  connects the button  45  to the tongue  33 , at about the middle of the tongue member  33  between the pairs of extended teeth  39 . The shaft passage  27  is sized to accommodate the plug  15 . The shaft passage is preferably about 10.0 mm long, 28.5 mm wide and 2.3 mm across (i.e. the shaft passage portion receiving the plug prongs  21  and excluding the shaft passage portion housing the tongue  33  or 5.9 mm across including the portion housing the tongue  33 ). The socket walls  35 ,  43  are preferably 2.2 mm thick and formed at about a 12 degree angle with the base  29  so that the plug  15  is not exactly vertical when plugged into the socket  11 . The tongue  33  is preferably about 24.5 mm wide and can be pushed back 14 degrees from its normal position (i.e. when the plane of its teeth  39  is parallel to the inner and outer socket walls  35 ,  43 ) against the inner wall  35 , and the resilient hinge  37  is preferably about 0.4 mm thick. Preferably, the orifice  41  is about 11.8 mm wide and 6.0 mm down, the button  45  is about 5.3 mm long, 3.0 mm down, and 8.7 mm at the base, narrowing at 8 degrees towards the outer end, and the stem  47  is about 6.0 mm across. 
         [0049]    A user can attach a shoe upper  3  to a sole  1  by inserting and pushing each plug  15  down into its corresponding socket  11 , until each prong  21  engages the tongue  33 . To exchange the shoe upper for one of a different pattern, color or design, the user depresses with a finger each button  45 , causing the respective stem  47  to urge the tongue member  33  towards the inner wall  35  of the socket  11  sufficiently for the teeth  39  of the tongue  33  thereof to disengage and unlatch from the plug teeth  25 , and pulls the unlatched plug  15  upwards. No accessory tool is kept at hand, fetched or searched for, and scant human force is required to unlatch the plugs. The buttons are sufficiently conspicuously arranged so that a user can locate and press the buttons, even if her fingernails are long or have just been painted, and yet are sufficiently concealed so as not to interfere with the aesthetics of the shoe sole. 
       Manufacture: 
       [0050]    The sockets  11 , the plugs  15  and the sole  1  can be molded. Integrated one-piece constructions are preferred. Methods for molding the plug  15  are well known in the art. The socket elements, including the socket walls, base, tongue, stem and button, are preferably formed integrally in a single piece. However, creating a die for manufacturing the socket  11  is complicated when the tongue  33  and button  45  are to be integrated into a single piece with the socket walls  35 ,  43 , and  29 . According to another aspect of the invention, the socket  11  is initially molded with a shaft passage  27  open from the top opening  13  to its bottom.  FIGS. 8A and 8B  illustrate the initial socket design. The die is shaped to include an extended base sheet comprised of a proximal portion  51  about the bottom shaft opening and a remote portion  53  connected to the proximal portion by a thin hinge portion  55 . The hinge portion  55  is preferably about 0.2 mm thick. The base portions  51 ,  53 , and  55  are molded integrally with the rest of the socket components in one piece. 
         [0051]    Once the mold is set and the socket  11  is removed from the die, the remote base portion  53  is folded back under the proximal base portion  51  about the base hinge portion  55 , thereby closing off the base  29  of the socket shaft passage  27 . The socket  11  can thereafter be placed in a die for molding the sole  1 , with the socket opening  13  against the bottom of the upside-down sole die. Both ends of the shaft passage  27  are thus effectively sealed to avoid resinous sole material from seeping into the shaft passage, which if it remained would obstruct the insertion of the plug during use. 
         [0052]    A further problem of keeping the flowable sole material out of the socket shaft passage during molding is associated with the orifice  41  in the outer wall  43 . The orifice  41  allows the button  45  and/or stem  47  to movably traverse the outside wall  43   FIG. 9  shows a preferred embodiment that provides a solution to this problem. The socket  11  is molded with a thin, frangible membrane  59 , preferably about 0.1 mm thick, flush with the outer wall  43  that seals the orifice  41 . The membrane  59  prevents resin from seeping into the socket  11  through the orifice  41  during the molding of the sole. 
         [0053]    Furthermore, the button  45  can be shaped so as to provide a large base area bearing against the membrane  59 . The sole  1  is cast in a die wherein the entire socket shaft passage is maintained free of resinous material. Once the sole has set and is removed from the die, with the sockets  11  (preferably about six sockets per shoe) embedded therein, the release operation can include a step of pressing each button  45  to breach the frangible membrane  59 , since the latter has already served its resin prevention purpose. 
         [0054]    A particularly preferred embodiment is shown in  FIGS. 10 and 11 .  FIG. 10  shows a cap  61 .  FIG. 11  is a sectional view of the socket of  FIG. 8A , taken through a horizontal plane as shown in  FIG. 9 , showing the cap  61  positioned to surround the outer wall  43 , sidewalls, and part of the inner wall  35  of the socket  11 , thereby covering the button  45  and enclosing an air space environment or gap  63  surrounding the button  45 . The cap  61  is generally a four-sided piece of plastic partially opened at an inner side  65 , and has a rounded convex outer side  67 , which, in position, forms a cover for the button  45 . During manufacture of the sole  1 , the outer wall  76  of the cap  61  prevents the flowable resin (for example, polyurethane) that is injected inot the mold from entering in the air gap  63 , which upon curing would prevent the button from being depressed with a finger. 
         [0055]    The invention has herein been described in relation to an injection system. The component parts of the push button system can be glued in place in the cavity of the out sole. The glue system works the same as the injection system, but using glue is less expensive and has a high yield rate. 
         [0056]    The outer cap wall  61  further provides a button area which is both enlarged and resilient. The cover wall  67  is more preferably convexly curved to provide resilient inward flexure for optimum operation. One or more recesses  69  provided at the bottom of the sidewalls accommodate anchorage flanges  71  provided in the socket base, as shown in  FIG. 5 . 
         [0057]    Another embodiment of a socket is shown in  FIGS. 12 and 13 . The socket  11  comprises an anchoring flange  71  extending from the inner wall  35  from a position intermediate the slot opening  13  and the base of the shaft passage  27 . A socket enclosure, shown as a boat-shaped cap  61 , surrounds the lower portion of the socket  11 , and seals off the shaft passage  27  at the base. The cap  61  has a base  75 , a back wall  72 , and a pair of side walls  73  having a lower rear portion  74 , and a front wall  67 . The back wall  72 , the side walls  73 , and the front wall  67  surround the lower perimeter of the socket  11 , and affix the cap  61  to the socket  11 . The base  75  of the cap  61  seals the bottom of the socket. The height of the back wall  72  and the rear portion  74  of the side walls accommodate the anchoring flange  71 . In the illustrated embodiment, the cap  61  snaps onto the bottom of the socket  11  and remains affixed throughout the molding process. The taller, forward portions  76  of the sidewalls and the front wall  67  each extend up to the top end of the socket, and surround and seal off the air space surrounding the button  45  extending from the outer wall  43  of the socket  11 . Depressing the outer wall  67  engages the button  45  to operate the coupling device. The large surface area of the cap wall  67  provides an outer resilient wall that has a much larger area for the finger to apply the disengaging force, which increases the force that can be exerted on the tongue  33 . 
         [0058]    The cap  61  seals the socket and the air space around the button  45  to prevent flowable resin from entering the socket and the air space surrounding the button. When using a resilient resin such as polyurethane, invasion of the resin into the socket or in the air space around the button can lock the tongue and button in position, and prevent proper operation of the coupling device. 
         [0059]      FIG. 14  shows a plan view of a socket assembly  18  consisting of the socket  11  with the cap  61  affixed, positioned in the top surface  5  of the sole  1 . The rounded button  45  is positioned within the air space defined by the sidewall portions  76  and front wall  67  of the cap  61 . The socket  11  and cap  61  are disposed proximate the lateral outer wall  9  of the sole. The front wall  67  of the cap is typically configured to be sufficiently flexible to allow facile depression of the front wall  67  and of the button  45 , making facile the operation of the socket. The hump mark  19 , formed from the sole resin material covering the outer wall  67 , identifies the position of the cap front wall  67  and the button  45  to allow a user to locate and depress the button with a finger, while being generally unnoticeable. 
         [0060]      FIG. 15  shows a set of molds that can be used to make the show sole that incorporates a plurality of the coupling devices. Illustrated are a top mold Ill, a middle mold  112 , and a base mold  113 . The molds are arranged so that the lower surface  114  of the top mold element  111  mates with the upper surface (not shown) of the middle mold  112 , and the lower surface  115  of the middle mold  112  mates with the upper surface  116  of the base mold  113 . The lower surface  114  of the top mold  111  provides the imprint of the top surface of the completed shoe sole, while the upper surface  116  of the base mold  113  provides the imprint for the bottom surface of the shoe sole. The molds are configures so that hinge members  119  on the base mold  111  engage with hinge members  120  on the middle mold  112  for easy positioning and alignment. The opposing ends of the molds are typically secured with a clamp means (not shown). The top mold  111  is likewise held in the proper position to the other two molds with a clamp means. The molds are positioned in the proper molding position with one another using mated alignment pins and  118  and orifices  117 . In the illustrated embodiment, four socket assemblies  18  which are semi-permanently affixed along the edge  121  defined by the inner opening  122  of the middle mold  112 . A flowable resin is then injected into the mold to form the sole  1  having the imbedded sockets, according to well-known molding techniques. 
         [0061]    During the molding process, the socket can also be provided with a top cover that covers the slot opening  13 . The cover typically has at least one pin depending downward from the cover into the slot passage  27  and between the tongue  33  and the inner wall  35 . The pin prevents the tongue from being biased toward the inner wall (toward its disengaged position) in response to pressure exerted upon the button  45  during the molding process. The cover also covers the top opening of the socket during the process of spray painting the molded sole, preventing paint from entering inside the socket, which could sabotage its operation. 
         [0062]    Although the cover wall  67  provides the resin-exclusion function of the membrane  59  in the first embodiment, it is preferred to include the membrane  59  since it resists depression of the cover wall  67  and the button  45  under the pressure of the injected molding resin, which otherwise might prematurely depress the cover wall and button and, if cured under this condition, could cause the coupling device to malfunction. 
         [0063]    While the invention has been described with reference to preferred embodiments, it will be understood by those skilled in the art that various changes can be made and equivalents can be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications can be made to adapt a particular situation or step to the teachings of the invention includes all embodiments falling within the scope of the appended claims.