Patent Publication Number: US-7219445-B2

Title: Locking mechanism for securing detachable shoe uppers

Description:
BACKGROUND OF THE INVENTION 
     The invention relates to an attachment mechanism and system used to accessorize, customize and/or personalize footwear with interchangeable uppers or straps, especially open shoes and sandals. More particularly, this invention presents a safe, secure and easy system for the attachment and detachment of shoe uppers and straps to shoes and sandals. This invention allows both the manufacturer and wearer to promote and display fashion and theme material of their own choosing, with the freedom to change the material or message without having to change footwear or specifically without having to change the sole portion of the footwear. 
     Footwear tends to be relatively expensive, and is often chosen to match particular items of dress. A plethora of dress items is usually matched to a much smaller universe of available footwear, so that the footwear is chosen in basic colors and styles to coordinate with a larger universe of dress items. Footwear is also purchased according to season, degree of formality and heel height, with sandals and open-toed shoes predominating in the warmer months. Coordinating even this limited selection with wardrobe items can be difficult, and it is too expensive to purchase a new pair of shoes or sandals for each ensemble. The invention also allows a large variety of footwear to be stored in a much smaller space due to the variations available with each sole portion. 
     Accordingly, the desirability of footwear with convertible style has been appreciated. The prior art has propose numerous solutions, including those set out in U.S. Pat. No. 4,839,948 to Boros, which is incorporated by reference herein for all purposes. As noted in Boros, the concept of replaceable uppers is well established, wherein a sole is provided with a plurality of interchangeable uppers. Typically the sole is in a basic or neutral color, whereas the uppers are supplied in an array of colors and designs. Using a system of interchangeable uppers with a single base shoe unit, the user can have a pair of shoes that compliment a variety of apparel for reduced cost. 
     The prior art, however, has not provided an entirely satisfactory solution to the problem of easily attaching and detaching the uppers to the sole with a minimum of inconvenience. Other problems ensue where the sole portion or the entire shoe must be specially manufactured to accommodate the removable uppers. Further problems occur when manufacturing complex mechanisms to attach and detach the uppers, or mechanisms that require the application of special tools. Another problem is the appearance of the attachment mechanism itself. A single, distinctive piece, if perceptible on the outside of the shoe, may conflict with the uppers and the overall appearance of the footwear, defeating the one of the basic purposes of interchangeable footwear. 
     Accordingly, it is an object of the present invention to provide improvements in the attachment system for convertible footwear. 
     Another object of the invention is the provision of an improved engagement means for detachably securing the upper portion or strap to the sole of the shoe or sandal. 
     Another object of the invention is to provide engagement means that are readily and conveniently usable by the wearer. 
     Another object of the invention is the provision of engagement means that will reliably and securely affix the upper to the sole and provide sufficient load bearing capacity to offset the upward pressure of the instep of the wearer on the shoe upper. 
     Another object of the invention is the provision of attractive and easily matched engagement means. 
     Another object of the invention is the provision of a releasable fastener in the form of a separately manufactured clasp that can be used with otherwise conventional footwear. 
     Another object of the invention is to provide a fastening system that allows for various configurations of straps on a single sole portion. 
     Another object of the invention is to provide a fastening system that allows interchangeable straps for different heel heights, adapted for the specific load bearing necessity of the particular footwear configuration. 
     And another object of the invention is the provision of a releasable fastener that is inexpensively manufactured. 
     BRIEF SUMMARY OF THE INVENTION 
     To achieve the desired objects of the invention as set forth herein, the releasable fastening system here is adapted from clasps used in jewelry design. A detachable, interchangeable shoe upper or sandal strap has at least two contact points with the lower sole portion of the footwear. The upper or strap is secured to a retainer by means of a releasable fastener. The retainer is secured to the sole portion of the footwear, preferably by attaching one end of the retainer underneath the insole of the footwear by means of adhesive. However, the retainer may be secured by other means, including screws securing one end of the retainer to the lateral edge of the sole. The retainer itself is preferably made of a strong, durable, flexible material and is a relatively narrow and elongated strip with its lower end glued, sewn or otherwise attached to the article of footwear. The other or upper end of the retainer preferably forms a receiving loop for holding the releasable fastener. In an alternative embodiment, the retainer is secured directly to a portion of the releasable fastener, preferably by welding or soldering, and extends underneath the insole at about a ninety degree angle from the releasable fastener when in use. 
     The detachable shoe upper or strap typically has a left end portion and a right end portion. At least one end of the detachable shoe upper or strap is secured to an upper bar or preferably the rectangular metal loop of the releasable fastener, the upper bar preferably having a horizontal dimension sufficient to that when in the engaged position the strap will lay flat without binding or crimping. When attaching a shoe upper or strap end to the upper bar of the releasable fastener, an open end of the strap is passed through the open section of the upper bar. The strap&#39;s end is preferably looped around the upper bar and is then closed about itself to form an attachment loop. The attachment loop is preferably kept closed by sewing or stitching the end to the upper portion of the strap about the upper bar, and may be reinforced by a gluing and stitching on the underside. 
     A lower bar or preferably a second metal rectangular loop is secured to a retainer. The retainer is preferably formed of a flexible material such as leather or fabric, and is preferably looped around the lower bar of the releasable fastener, the lower bar preferably having a horizontal dimension sufficient to that when in the engaged position the retainer will lay flat without binding or crimping. The retainer is fastened to the sole portion of the shoe or sandal, preferably by gluing the second, distal end of the retainer underneath the insole of the sole portion. The releasable fastener itself has a substantially hollow outer barrel carrying one bar or loop, and an inner barrel carrying a second bar or loop, the diameter of the inner barrel being less than a diameter of an inner surface of the outer barrel so that the inner barrel is slidably engagable with the outer barrel and is retained in an engaged position with a securing mechanism. The securing mechanism is preferably either a magnet or a depressable biasing member. This engagement of the inner and outer barrels creates a transient interlock of the releasable fastener and the upper and lower bars, thus anchoring the shoe upper or strap with the retainer and therefore the sole portion of the shoe or sandal. With this system, a variety of shoe uppers or straps can be temporarily attached and interchanged between selected footwear. 
     In a more specific embodiment, the male element is a cylindrical bar and the female element is in the form of a hollow cylindrical receptacle. Attached to each is a wire loop, each preferably forming a rectangle with side bars elongated to hold the retainer on one side and the shoe upper on the other without binding or crimping, and to supply even strength to support the upward pressure of the instep on the shoe upper without inadvertently disengaging or releasing. 
     The receiving strip, which forms a receiving loop when it is attached to the releasable fastener, as well as the shoe upper or strap, can become a designer&#39;s accent or vanity label. When custom embroidered or printed with logos, symbols, statements, or such other ornamentation it is presented as a manufacturer&#39;s/designer&#39;s vanity or display label. Employing a label on the retaining strip would permit the system to stylize and brand the footwear with a single element and yet when in place, would also allow different, unbranded uppers or straps to be affixed without losing brand identity. 
     In another embodiment, the retainer can be a metal tab that is preferably the same width as a barrel of the releasable fastener to which the tab is attached. In this embodiment, the metal tab is secured directly to a barrel of the releasable fastener, and the tab portion lies between the sole portion and the insole. The tab is preferably secured to the sole portion with an adhesive, or with nails or screws preferably countersunk into the sole. And due to the weight of the wearer bearing down upon the insole and thus on the tab, further support is provided to keep the fastening system in place during use. For the comfort of the wearer, the sole portion would have a depression or countersink to accommodate the thickness of the tab so that the upper surface of the tab is substantially flush with the upper surface of the sole when in place. 
     In any embodiment, the invention provides a stylized releasable fastener that may coordinate with many different articles of footwear and apparel. The ease and versatility of this shoe attachment system is a system where customized or thematic expressions on footwear can be changed by the user or wearer simply by changing the upper. This is demonstrated through the unrestricted placement of the shoe upper or strap, while maintaining the same retainer attached to the sole portion, with the ability to personally select from the endless variety of uppers and straps, and different configurations of straps appropriate for soles with different heel heights, such as front, middle and back strap configurations. By using the same sized retainer across different heel heights the user can interchange straps with different height heel or sole portions. The retainers may be used on closed toe shoes and boots, and allow for different embellishments and colors on the shoe uppers. With the uncomplicated engagement means, the releasable fastener is workable even by those with limited motor skills. Other objects and advantages will be more fully apparent from the following disclosure and appended claims. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The above-mentioned and other features and objects of this invention and the manner of obtaining them will become apparent and the invention itself will be best understood by reference to the following description of an embodiment of the invention taken in conjunction with the accompanying drawings, wherein: 
         FIG. 1  is a perspective view of an article of footwear having the releasable fasteners of the present invention; 
         FIG. 2  is a view of an article of footwear having one end of a strap in released position; 
         FIG. 3  is a view of a releasable fastener in the engaged position; 
         FIG. 4  is a view of a releasable fastener in a position between the engaged position and released position; 
         FIG. 5  is a view of a releasable fastener in a released position; 
         FIG. 6  is a view of an alternate form of securing the releasable fastener in an engaged position. 
         FIG. 7  is a view of an alternate form of securing the releasable fastener. 
         FIG. 8  is a side view of an alternate form of securing the releasable fastener of  FIG. 7 . 
         FIG. 9  is a view of the placement of the alternate form of securing the releasable fastener of  FIG. 7 . 
     
    
    
     DETAILED DESCRIPTION 
     Turning now to the drawings,  FIG. 1  shows an article of footwear  1  having a sole portion  2  with an insole  3  covering the upper surface of sole portion  2 . The article of footwear  1  also has a flexible instep strap  4  formed of a transparent, plastic material. The instep strap is shown here for additional support due to the high heel  5  and high arch  6 . The invention may be employed with a multiplicity of straps or shoe uppers, and the straps may be employed towards the toe portion of the footwear, the instep or the heel portion or used to support the ankle of the user. Strap width and length should be varied according to the anticipated user, such as for men, women and children, overall preferably between one-quarter of an inch and one and one-half of an inch in width. Preferably, for a woman&#39;s article of footwear, the strap would be between three-eights of an inch and one inch in width. 
     The shoe upper, here shown as a strap  7 , is secured to the releasable fastener  8  by looping the strap material about an upper bar  9  and securing the strap  7  by stitching the loop closed about the upper bar  9 . The upper bar  9  forms a metal loop in a substantially rectangular shape that has a horizontal dimension  9   a  ( FIG. 3 ) sufficient to support the strap  7  without crimping or impinging upon the strap  7 .  FIG. 2  shows the detail of the releasable fastener  8  in the disengaged position. A lower bar  10  carried by the releasable fastener  8  is similar in construction to the upper bar  9 . Use of the terms “upper” and “lower” herein is for convenience, and does not necessarily indicate the relative positions of the upper bar  9  and lower bar  10  when in use, nor does it restrict the fastening of the shoe upper or strap to a particular bar. The retainer  11  is here shown as a flexible, glossy fabric material similar in composition to the strap  7 , although different materials and labels may be employed on the retainer  11  to coordinate with a variety of shoe uppers or straps. The length of the retainer  11  may also be varied from a relatively short length whereby the retainer  11  would be barely visible to an observer, to a longer retainer which may be customized with ornamentation or manufacturer or designer labels or marks. The retainer  11  is attached to the sole portion of the article of footwear preferably by inserting beneath the insole  3  an end of the retainer  11  distal from an end looped about the lower bar  10 , and securing the retainer  11  in place with adhesive. Alternatively, the retainer  11  may be secured to a lateral edge  12  of the sole portion  2  by means of one or more screws  13 . 
     Turning to  FIG. 3 , a releasable fastener  8  of the claimed invention is shown in more detail. The releasable fastener  8  is preferably made in part from iron, steel or any other magnetic metal or alloy where a magnet is employed to retain the releasable fastener  8  in an engaged position. Otherwise, the releasable fastener  8  is preferably metal, and preferably made in whole or in part of a metal selected from the group consisting of titanium, steel, silver, brass and nickel. The metal may also be plated with a shiny metal such as gold or silver or chrome to match the overall look of the footwear or the removable upper or strap. The magnetic material is employed in this embodiment because the releasable fastener  8  shown in  FIG. 3  in the engaged position, i.e., closed, is held in that position by a magnet or magnetized end portion of the releasable fastener  8 . In  FIG. 4 , it is more clearly seen that the releasable fastener  8  is formed of two interlocking, slidably engaging barrels, where the outer barrel  14 , shown here with surface ornamentation, has a hollow cylindrical interior that extends for substantially the length of the outer barrel  14 . In the partially disengaged releasable fastener  8  of  FIG. 4 , it can be seen that an inner barrel  15  is a cylindrical pin, preferably solid, with an outer surface having a dimension (radius) less than the dimension (radius) of the inner surface of the hollow cylindrical interior of outer barrel  14 . The outer barrel  14  has a slot extending substantially the length of the barrel  14  into which the [bar] slidably engages the outer barrel  14 . The slidable engagement of the [bar] and the barrel  14  resists torsion from the flexing of the strap or the retainer  11 , preserving the fastener  8  in a substantially rigid form. The inner barrel  15  is held in the engaged position with respect to outer barrel  14  by means of a magnet. The magnet may be located in the pin head  15   a  of inner barrel  15  or the left end  14   a  of outer barrel  14 . Alternatively, the magnet may be located in the distal end  15   b  ( FIG. 5 ) of inner barrel  15  or at the distal end  14   b  of outer barrel  14 . To aid the magnet in holding the fastener  8  in the engaged position, it is preferable that the fastener  8  be angled downwardly where appropriate so that the inner barrel  15  is further held within the outer barrel  14  by the aid of gravity. 
     In place of a magnet, the releasable fastener  8  may be held in place with a biasing member  16  as shown in  FIG. 6 . The biasing member  16  exerts outward frictional force against the inner surface of the outer barrel  14 . The releasable fastener  8  may also be held in place with a frictional fit either alone, with a magnet or with a biasing member for increased stability in the engaged position. 
       FIG. 7  shows an alternative fastener for use with the present invention. Instead of a lower bar, the fastener employs a tab  17 , preferably metal, and preferably made in whole or in part of a metal selected from the group consisting of titanium, steel and nickel. The tab  17  is secured to a barrel  18  for engagement with a mating barrel in the same way as outlined above with respect to the releasable fastener  8 . The preferred method of securing the tab  17  to the barrel  18  is by welding or soldering. The length of the tab  17  is preferably about one inch.  FIG. 8  shows a side view of the tab  17 , having a preferable thickness of at least 1 millimeter.  FIG. 9  shows the attachment of the tab  17  to the sole portion  19 , preferably by the use of an adhesive. The insole portion  20  is secured to the sole  19  over the tab  17 , covering the tab  17  but leaving the barrel  18  exposed so as to be engagable with a mating barrel  21  secured to strap  22 . A matching tab  17   a  is shown in  FIG. 9 . In use, the weight of the user will also help keep the tab  17  in a secure engagement with the sole  19  when the footwear is in use. 
       FIG. 10  shows an alternative means of employing the invention in a releasable fastener. The outer barrel  23  is a groove or channel cut into a piece of metal  24 , with the corresponding inner barrel  25  being carried on a mating piece of metal  26 . In the instant description, the biasing member  27  is a ball bearing which nests within a corresponding depression in the lower mating surface of the other metal piece  26  when in the engaged position in order to retain the outer barrel  23  and the inner barrel  25  in an engaged position. The releasable fastener is shown in  FIG. 10  with the tab  17  attached to the metal piece  24  carrying the outer barrel  23  (the groove or channel). A slot may be cut through the metal piece  26  so that a strap (not shown) may be threaded through the slot to attach a shoe upper to the releasable fastener. Alternatively, a loop such as that shown by reference numeral  9  in  FIG. 1  could be attached to one or both of the metal pieces  24  and  26 . 
     Since other modifications or changes will be apparent to those skilled in the art, there have been described above the principles of this invention in connection with specific apparatus, it is to be clearly understood that this description is made only by way of example and not as a limitation to the scope of the invention.