Patent Publication Number: US-2007107263-A1

Title: Heel insert

Description:
STATEMENT REGARDING FEDERALLY FUNDED RESEARCH  
      This invention was not made under contract with an agency of the US Government, nor by any agency of the US Government. 
    
    
     FIELD OF THE INVENTION  
      This invention relates generally to shoes and specifically to retrofit-able heel inserts for shoes.  
     BACKGROUND OF THE INVENTION  
      Variation in individual&#39;s shape and size of feet mean that different individuals find that different shapes of shoe support provide comfort. As a result, different shoes provide different levels of comfort for different people. However, this by itself does not provide comfort at all times.  
      For example, most individuals find that their feet are just slightly different sizes or shapes. An individual may have a leg discrepancy, and some individuals have foot pronation or supination or these conditions may just occur in a sole, heel or foot. Other individuals find that no pair of shoes really provides real comfort for personal reasons of choice, foot shape and so on.  
      One known solution is the insole insert, an extremely soft “foot shaped” layer of material for insertion (retrofit) into a shoe.  
      However, traditional insole shoe inserts present problems to most users. In particular the insole insert takes up space covering a substantial portion of the planform of the shoe. This results in the insole insert taking up excessive space inside the shoe, often meaning that users cannot wear them due to discomfort of toes or some other part of the foot.  
      In addition, most insole inserts are composed of an extremely soft material which compacts easily down to some minimal thickness, thus robbing the user of most of the theoretical benefit of the device.  
      Yet another problem with the insole insert is that it is essentially “foot shaped”, that is it is geared towards users who have some “whole foot” discomfort, as opposed to those who find that they need particular support at a particular point of the foot.  
      Another known solution is the arch support, a device whose shape is defined by the space between the sole of the shoe and the arches of some individuals. However, this particular solution is specialized and suits only those individuals who have this exact problem and have the exact shape of arch for which the support is designed.  
      It would be advantageous to provide a device offering a degree of very firm support, able to sustain the actual weight of the user.  
      It would further be advantageous to provide a device small enough to offer support to only one portion of the user&#39;s foot, without taking up space in other parts of the shoe.  
      It would further be advantageous to provide a device of a shape able to fit easily into a variety of locations in a shoe.  
      It would further be advantageous to provide a device firm enough to support a user&#39;s weight at the heel, yet resilient enough to provide comfort to the user.  
     SUMMARY OF THE INVENTION  
      General Summary  
      The present invention teaches that an improved shoe insert may be made in a smaller size and of a material which is firmer yet flexible and more resilient than in prior art devices. An advantageous trapezoidal planform is also taught, in which the rear edge is shorter than the parallel front edge. The device may have a rear edge having a thickness of a few millimeters (up to ⅛ inch (0.375 inch)) while the thickness of the device decreases regularly to the front edge, at which point the thickness reaches zero. The size of the device may advantageously be in the range from 1 inch in rear length to 1.5 inches in rear length, 1.25 inch in front length to 1.75 inch in front length, and from 1 inch in width (defined as the distance separating the parallel rear and front edges) to 1¼ inches in width.  
      The device may also be made in a rectangular embodiment of approximately the same dimensions, although the trapezoidal embodiment allows more support and cushion underneath the foot.  
      One material which has been determined to have the desirable hard yet highly resilient properties is rubber, specifically NEOPRENE™ brand rubber, a blend of styrene butadiene rubber (SBR), neoprene (CR) and nitrile rubber (NBR). It is the most flexible of the rubber family. Shore A Durometer  30  is presently used and test to show that the tensile strength is 1000 PSI at 1/32 inch to 1 inch gauge thickness and will support from 125 to 175 pounds of weight repeatedly applied and also for long durations of time before any compression sets in.  
      NEOPRENE™ as used in the device may be extruded.  
      Summary in Reference to Claims  
      It is therefore another aspect, advantage, objective and embodiment of the present invention to provide a shoe insert comprising: 
          a body of a firm resilient material;     the body having a bilaterally symmetrical trapezoidal planform having four sides: a back, a front, and two sides, the back side parallel to and shorter than the front side, the body having rounded corners;     the body having in cross section a first thickness at the back side, the thickness of the body decreasing regularly to a second thickness the front side;     the body having a bottom surface and a top surface;     an adhesive layer disposed upon the bottom surface of the body;     a backing layer disposed upon the adhesive layer.        

      It is therefore another aspect, advantage, objective and embodiment of the present invention to provide a shoe insert wherein the thickness at the front side is zero millimeters.  
      It is therefore another aspect, advantage, objective and embodiment of the present invention to provide a shoe insert wherein the thickness at the back side is 0.125 inch.  
      It is therefore another aspect, advantage, objective and embodiment of the present invention to provide a shoe insert wherein the firm resilient material comprises rubber.  
      It is therefore another aspect, advantage, objective and embodiment of the present invention to provide a shoe insert wherein the rubber comprises NEOPRENE brand rubber.  
      It is therefore another aspect, advantage, objective and embodiment of the present invention to provide a shoe insert wherein the length of the short edge is 1.25 inch.  
      It is therefore another aspect, advantage, objective and embodiment of the present invention to provide a shoe insert wherein the length of the long edge is 1.5 inch.  
      It is therefore another aspect, advantage, objective and embodiment of the present invention to provide a shoe insert wherein the distance between the short edge and the long edge is 1.125 inch.  
      It is therefore another aspect, advantage, objective and embodiment of the present invention to provide a shoe insert wherein the adhesive further comprises any high bond semi-permanent adhesive.  
      It is therefore another aspect, advantage, objective and embodiment of the present invention to provide a shoe insert comprising: 
          a body of a firm resilient material;     the body having a planform having four sides: a back, a front, and two sides, the back side parallel to and the same length as the front side, the body having rounded corners;     the body having in cross section a first thickness at the back side, the thickness of the body decreasing regularly to a second thickness the front side;     the body having a bottom surface and a top surface;     an adhesive layer disposed upon the bottom surface of the body which may be very high bond (VHB) semi-permanent adhesive, known for its strength and durability in extreme applications,     a backing layer disposed upon the adhesive layer.       

    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       FIG. 1  is a planform top view of a first embodiment of the invention.  
       FIG. 2  is a cross-sectional side view of the first embodiment of the invention.  
       FIG. 3  is a left side view of the first embodiment of the invention.  
       FIG. 4  is a right side view of the first embodiment of the invention.  
       FIG. 5  is a bottom view of the first embodiment of the invention.  
       FIG. 6  is a rear view of the first embodiment of the invention.  
       FIG. 7  is a front view of the first embodiment of the invention.  
       FIG. 8  is a planform top view of a second embodiment of the invention.  
       FIG. 9  is a cross-sectional side view of the first embodiment of the invention.  
       FIG. 10  is a left side view of the first embodiment of the invention.  
       FIG. 11  is a right side view of the first embodiment of the invention.  
       FIG. 12  is a bottom view of the first embodiment of the invention.  
       FIG. 13  is a rear view of the first embodiment of the invention.  
       FIG. 14  is a front view of the first embodiment of the invention.  
       FIG. 15  is a partial top view of a shoe with the invention in use in a first manner.  
       FIG. 16  is a partial top view of a shoe with the invention in use in a second manner.  
       FIG. 17  is a partial top view of a shoe with the invention in use in a third manner. 
    
    
     INDEX TO REFERENCE NUMERALS  
     
         
          Body  100   
          Top surface  102   
          Rear side  104   
          Front side  106   
          Right side  108   
          Left side  110   
          Bottom surface  112   
          Adhesive layer  114   
          Backing layer  116   
          Rounded corner  120 ,  122 ,  124 ,  126   
          Body  200   
          Top surface  202   
          Rear side  204   
          Front side  206   
          Right side  208   
          Left side  210   
          Bottom surface  212   
          Adhesive layer  214   
          Backing layer  216   
          Rounded corner  220 ,  222 ,  224 ,  226   
          Shoe  500   
          Shoe upper  502   
          Heel insert  504   
          Shoe interior  506   
          Shoe  600   
          Heel insert  604   
          Shoe  700   
          Heel insert  704   
       
    
     DETAILED DESCRIPTION  
       FIG. 1  is a planform top view of a first embodiment of the invention.  FIG. 2  is a cross-sectional side view of the first embodiment of the invention. These diagrams of the first embodiment of the invention show the presently preferred embodiment of the invention, which is also the best mode now contemplated for carrying out the invention.  
      Body  100  is a trapezoidal shape in planform ( FIG. 1 ), an acute triangle viewed from the side ( FIG. 2 ). Top surface  102  is thus trapezoidal and defined by four sides: rear side  104  and front side  106 , right side  108 , left side  110 .  
      Rear side  104  and front side  106  are parallel to each other, while right side  108  and left side  110  may be symmetrical (in the preferred embodiment) or asymmetrical in angle. In the best mode now contemplated, rear side  104  is shorter than front side  106  (front side  106  is longer than rear side  104 ).  
      Rounded corners  120 ,  122 ,  124 ,  126  at the junctions of the sides provide a firmer grip and increased comfort. Without wishing to be bound by any theories, is it believed that sharp corners may be sensed by the bottom of the foot, leading to potential discomfort, and that sharp corners are more likely to lose adhesion, begin to project upwards, and thus turn into a “snag” waiting to get caught on a user&#39;s sock and then cause the entire device to lift away from the sole of the shoe.  
      This may also be placed under a removable insole a shoe.  
      The trapezoidal configuration offers a number of benefits. One benefit is that the narrowing of the rear side allows the device to be used in narrower potions of shoes. In particular, the rear end of the shoe narrows considerably, and a narrower rear edge allows the insert of the invention to sit closer to the rear of the shoe.  
      Bottom surface  112  ( FIG. 2 ) has an adhesive layer  114  and backing layer  116 . Adhesive layer  114  may be an adhesive which may be very high bond (VHB) semi-permanent adhesive, known for its strength and durability in extreme applications. Backing layer  116  may be used to prevent the adhesive from becoming dirty prior to the desire use.  
      In one preferred embodiment, the adhesive is a glue having a high degree of “tack” (i.e. the ability to be lifted up and set in a new location and still stick) and may be semi-permanent even under extreme conditions.  
      Cross sectional  FIG. 2  also shows the “wedge” shape of the device: an acute triangle narrowing to zero thickness at the front side. The wedge shape produces torsion control which keeps the heel from moving from side to side. The first thickness at the rear side or rear edge  104  may advantageously be roughly 3 millimeters (about ⅛ inch), then the thickness in a regular manner (at a constant rate) decreases until the thickness is zero at the front side or front edge  106 . Obviously, the point at which thickness reaches zero may be said to define the front side  106 .  
      Body  100  is itself a hard or firm resilient material. While most prior art devices are soft pliable fabrics, the invention is not soft and pliable. On the contrary, the body  100  of the invention is firm and resilient yet flexible. In the preferred embodiment, the firm resilient material comprises rubber, such as NEOPRENE™ brand rubber. This is a blend of styrene butadiene rubber (SBR), neoprene (CR) and nitrile rubber (NBR). It is the most flexible of the rubber family. Shore A Durometer  30  is presently used and tested to show that the tensile strength is 1000 PSI at 1/32 inch to 1 inch gauge thickness and will support from 125 to 175 pounds of weight repeatedly applied and also for long durations of time before any compression sets in.  
      Without wishing to be bound by any theory, it is believed that the reason a firm resilient body is superior to a soft and pliable body is that the device is intended to provide actual support of the weight of the user. That is, most prior art devices simply sit flat under the full area of the sole of the foot, or else are arch support devices which project upwards into the area under the arch of the foot. The invention provides actual support, for example under the heel of the foot, and can be conveniently placed where needed, for example so that the entire weight of the user will rest for a split second during each step the person takes.  
      Thus the shoe insert should comprise a body of a firm resilient material, the body bilaterally symmetrical and trapezoidal in planform with round corners and with the back side parallel to and shorter than the front side.  
      In cross section, the body has a first thickness at the back side and the thickness of the body decreasing regularly to a second thickness the front side, which is preferably zero thickness.  
      The body bottom surface or top surface may have an adhesive layer disposed thereon with a backing layer disposed upon the adhesive layer.  
       FIG. 3  is a left side view of the first embodiment of the invention.  FIG. 4  is a right side view of the first embodiment of the invention.  FIG. 5  is a bottom view of the first embodiment of the invention.  FIG. 6  is a rear view of the first embodiment of the invention.  FIG. 7  is a front view of the first embodiment of the invention. Sides  110 ,  108 , and bottom and top surfaces  112  and  102  may be seen in these diagrams.  
      A back side thickness of 0.125 inch, (about 3 millimeters) has been tested and proven beneficial.  
      The size of the device may advantageously be in the range from 1 inch in rear length to 1.5 inches in rear length (25-40 millimeters), 1.25 inch in front length to 1.75 inch in front length (32-45 millimeters), and from 1 inch in width (defined as the distance separating the parallel rear and front edges) to 1.25 inches in width (25-30 millimeters).  
      A length of the short edge of 1.25 inch is presently most preferred, and a length of the long edge at 1.5 inch is presently most preferred. A distance between the short edge and the long edge of 1.125 inch is presently most preferred.  
      The trapezoidal shape provides is better than a rectangular shape for narrower spaces and provides more product underfoot, thus the trapezoidal shape is the presently preferred choice.  
       FIG. 8  is a planform top view of a second embodiment of the invention.  FIG. 9  is a cross-sectional side view of the first embodiment of the invention. Body  200  is of a rectangular planform, rather than trapezoidal. Top surface  202 , rear side  204 , front side  206 , right side  208 , left side  210 , and rounded corners  220 ,  222 ,  224 ,  226  are otherwise much as in the embodiment of  FIGS. 1 through 7 .  
      Thus the device may instead be a body of a firm resilient material having a rectangular planform having four sides: a back, a front, and two sides, the back side parallel to and the same length as the front side, and of course the sides also parallel and the same lengths, with rounded corners and a first thickness at the back side which decreases regularly to a second thickness the front side.  
      The bottom surface  212  and top surface  202  may then be much as disclosed: an adhesive layer  214  disposed upon the bottom surface with a backing layer  216  disposed upon the adhesive layer.  FIG. 10  is a left side  210  view of the first embodiment of the invention.  FIG. 11  is a right side  208  view of the first embodiment of the invention.  FIG. 12  is a bottom view of the first embodiment of the invention.  FIG. 13  is a rear view of the first embodiment of the invention.  FIG. 14  is a front view of the first embodiment of the invention.  
       FIG. 15  is a partial top view of a shoe with the invention in use in a first manner. Shoe  500  has shoe upper  502  and shoe interior  506 . Within shoe interior  506 , heel insert  504  is placed so that it is facing with the sloped upper surface facing towards the front of the shoe, to provide additional heel support.  
       FIG. 16  is a partial top view of a shoe with the invention in use in a second manner. Shoe  600  has heel insert  604  placed facing inwards towards the centerline of the user&#39;s body so as to provide additional support to one with a pronate condition. This support will aid in straightening the ankle to a more vertical orientation.  
       FIG. 17  is a partial top view of a shoe with the invention in use in a third manner. Shoe  700  has heel insert  704  facing outwards from the centerline of the user&#39;s body so as to provide additional support to one with a supination condition of the foot and ankle.  
      The disclosure is provided to allow practice of the invention by those skilled in the art without undue experimentation, including the best mode presently contemplated and the presently preferred embodiment. Nothing in this disclosure is to be taken to limit the scope of the invention, which is susceptible to various equivalents without departing from the scope and spirit of the invention. The scope of the invention is to be understood from the claims accompanying this disclosure.