Abstract:
A shoe insole (or sole) includes at least two elastomeric pads horizontally distinct from one another, each pad having a different rebound rate. The insole thereby provides at least one pad with relatively greater shock absorbing properties and at least one other pad with relatively greater energy return, or lift, properties. These differing characteristics allow an insole to be customized with regard to the specific use of a shoe.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     1. Technical Field  
         [0002]     The invention relates to an improved insole for a shoe. More particularly, the invention relates to an insole having impact-absorbing properties as well as energy return properties. Specifically, the invention relates to an insole having at least two elastomers each having different rates of energy absorbing and/or rebound properties.  
         [0003]     2. Background Information  
         [0004]     Many thousands of insoles have been designed for shoes to increase the comfort as well as the performance for various activities, especially different sports such as running, baseball, football, tennis and so forth. Each type of activity requires the foot to perform in a different way and thus insoles have been designed to aide in particular sports as well as in a general manner whereby shock absorbing properties and the like are improved. Various insoles have used liquid-containing cavities to provide improved shock absorption and comfort to the foot, for example, U.S. Pat. No. 3,724,106, U.S. Pat. No. 4,115,934, U.S. Pat. No. 4,471,538, U.S. Pat. No. 5,155,927, and U.S. Pat. No. 5,979,086. Other insoles have used air-filled chambers, such as U.S. Pat. No. 5,996,253. Some insoles have employed various structural features to provide cushioning, such as U.S. Pat. No. 5,642,575, which utilizes domes of resilient material for that purpose. Still other insoles use cushioning elements which are placed in various areas of the insole, such as the heel and the ball area of the foot. For instance, U.S. Pat. No. 6,176,025 utilizes such cushioning elements, whereby a cushioning element is made of a polymeric foam which is firmer than the surrounding polymeric foam of the remainder of the insole. Alternately, the patent uses a cushioning element using a gel-air mixture whereby an air cushioning pad is surrounded by an outer cushioning ring and the cushioning pad has a lower density than the outer ring.  
         [0005]     However, there remains a need for an insole having separate portions made of materials having different rebound rates, such that one section primarily absorbs impact energy while another portion returns energy to the foot after impact. While this concept is useful in a variety of configurations, it is perhaps most easily understood in regard to the motion of a runner, whereby it is desired to have a greater shock absorbing property in the heel as the runner&#39;s shoe impacts with the ground, along with a high energy return rate, or rebound rate, in the ball area of the foot to provide extra spring to the front of the foot as the runner propels himself forward.  
       BRIEF SUMMARY OF THE INVENTION  
       [0006]     The present invention provides an insole having a first elastomeric pad and a second elastomeric pad horizontally distinct from one another, each pad having a rebound rate; and the rebound rate of the first pad differing from the rebound rate of the second pad.  
         [0007]     The present invention provides a shoe having a sole comprising a first elastomeric pad and a second elastomeric pad horizontally distinct from one another, each pad having a rebound rate; and the rebound rate of the first pad differing from the rebound rate of the second pad. 
     
    
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS  
       [0008]      FIG. 1  is a bottom plan view of a first embodiment of the present invention.  
         [0009]      FIG. 2  is an exploded bottom plan view of the first embodiment.  
         [0010]      FIG. 3  is a top plan view of the first embodiment.  
         [0011]      FIG. 4  is a sectional view taken on line  4 - 4  of  FIG. 1 .  
         [0012]      FIG. 5  is a sectional view taken on line  5 - 5  of  FIG. 1 .  
         [0013]      FIG. 6  is a bottom plan view of a second embodiment of the present invention.  
         [0014]      FIG. 7  is a sectional view taken on line  7 - 7  of  FIG. 6 .  
         [0015]      FIG. 8  is a sectional view taken on line  8 - 8  of  FIG. 6 .  
         [0016]      FIG. 9  is a sectional view of a third embodiment of the present invention.  
         [0017]      FIG. 10  is a sectional view of a fourth embodiment of the present invention.  
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0018]     A first embodiment of the insole of the present invention is indicated generally at  10  and is shown particularly in  FIGS. 1-5 . A second embodiment of insole of the present invention is indicated generally at  100  in  FIGS. 6-8 . A third embodiment of the invention applies the concept to a sole of a shoe and is shown generally at  200  in  FIG. 9 . A fourth embodiment similar to the third embodiment is indicated generally at  300  in  FIG. 10 .  
         [0019]     Insole  10  has a toe or forward end  12 , a heel or rearward end  14 , and inner edge  16  situated along the arch side of insole  10  and extending generally the length thereof and an outer edge  18  opposite inner edge  16  which extends generally along the length of insole  10 . Insole  10  has an upper surface  17  and a lower surface  19 . Referring to  FIGS. 4-8 , insole  10  also includes an upper layer  20  having a lower surface  22  and an upper surface  24  upon which a foot rests when insole  10  is in use. Upper surface  17  of insole  10  coincides with upper surface  24  of upper layer  20 . Insole  10  further includes a lower layer  26  having a lower surface  28  and an upper surface  30  to which upper layer  20  is attached along lower surface  22  thereof. Upper layer  20  and lower layer  26  are each preferably formed of a polymeric foam material with upper surface  24  of upper layer  20  preferably being of a particularly durable quality to endure the various stresses received from the foot of the user. However, upper layer  20  and lower layer  26  can be made of a variety of materials as known in the art without departing from the spirit of the invention. Referring specifically to  FIG. 6 , insole  10  may be further broken down into a forefoot section  32 , which generally comprises a metatarsus section  34  and a toe section  36 , along with a midfoot section  37  situated rearwardly of forefoot section  32  and a heel section  38  rearward of midfoot section  37 . Midfoot section  37  includes an arch section  39  along inner edge  16 . Insole  10  further includes a first pad  40  divided into two side-by-side separated pieces in the general area of metatarsus section  34  and a second pad  42  in the general area of heel section  38 . First pad  40  may also be a single continuous piece or more than two pieces without departing from the spirit of the invention. First pad  40  has a lower surface  44  and an upper surface  46  to which lower layer  26  is attached along lower surface  28  thereof. Second pad  42  likewise has a lower surface  48  and an upper surface  50  to which lower layer  26  is attached along lower surface  28  thereof. Lower surface  28  of lower layer  26 , lower surface  44  of first pad  40  and lower surface  48  of second pad  42  are all generally on the same level. This is due to the fact that in the areas of first pads  40  and second pad  42 , lower layer  26  is recessed approximately the thickness of the respective pads  40  and  42 . The depth of these recessed areas  52  may vary and may even be eliminated without departing from the spirit of the invention. Alternate locations for first pad  40  and second pad  42  are hereafter more fully indicated in regard to the second embodiment.  
         [0020]     In accordance with one of the main features of the present invention, first pad  40  is horizontally distinct from second pad  42  and each pad is made of an elastomer having a different rebound rate. The term horizontally distinct in the exemplary embodiment means that the two pads  40  and  42  are physically separated with horizontal space therebetween. However, without departing from the spirit of the invention, horizontally distinct may also mean, for example, that the two pads  40  and  42  lie side-by-side in contact with one another or that the two pads  40  and  42  partially overlap one above the other as long as there are still two horizontally distinct portions having different rebound rates. In the first embodiment, the rebound rate of first pad  40  is greater than the rebound rate of second pad  42 . Thus, as for use with a runner, second pad  42  absorbs a greater amount of energy from the impact of a foot coming downwardly thereon in comparison to first pad  40 , which returns a relatively greater amount of the impact energy to the foot to help it spring upward and forward. In more common terms, second pad  42  tends to absorb or deaden the impact from the generally downward movement of the foot while first pad  40  relatively bounces back or returns the generally downward impact energy to create an upward lift.  
         [0021]     In accordance with another main feature of the present invention, the characteristics of the elastomers of first pad  40  and second pad  42  are as follows. The elastomer used in first pad  40  has a rebound rate ranging from 5.0% to 90.0%, a hardness with a durometer range of 30 to 70, Shore Hardness (00) scale, and a density ranging from 0.8 to 2.2. The elastomer of second pad  42  has a rebound rate ranging from 1.0% to 40.0%, a hardness with a durometer range or 20 to 70, Shore Hardness (00) scale, and a density ranging from 0.7 to 2.0. Preferably, the polymer of first pad  40  has a hardness with a durometer range of 35 to 70, Shore Hardness (00) scale while the polymer of second pad  42  preferably has a hardness with a durometer range of 20 to 55, Shore Hardness (00) scale.  
         [0022]      FIGS. 6-8  show the second embodiment, insole  100 . Insole  100  shows some of the endless configuration possibilities of the present invention and is numbered like insole  10  except for the pads and their relative locations as noted herein. As shown in  FIG. 6 , insole  100  includes a first pad  140  positioned generally in metatarsus section  34  along inner edge  16 ; a second pad  142  positioned in metatarsus section  34  along outer edge  18  adjacent but slightly spaced from pad  140 ; a third pad  154  positioned in midfoot section  37  along outer edge  18  and partially overlapping with second pad  142 ; and a fourth pad  156  positioned in heel section  38 .  
         [0023]      FIGS. 7 and 8  show the vertical position, in addition to the horizontal position, of each pad  140 ,  142 ,  154  and  156 . First pad  140  has a lower surface  144  and an upper surface  146 . Second pad  142  has a lower surface  148  and an upper surface  150 . Third pad  154  has a lower surface  158  and an upper surface  160 . Fourth pad  156  has a lower surface  162  and an upper surface  164 . First pad  140  ( FIG. 8 ) extends from upper surface  17  to lower surface  19  of insole  100  so that upper surface  146  and lower surface  144  of first pad  140  coincide respectively with upper surface  17  and lower surface  19  in the area of first pad  140 . Second pad  142  is generally in a side-by-side or lateral orientation with respect to first pad  140  and is inserted into upper layer  20  of insole  100 . Upper surface  150  and lower surface  148  coincide respectively with upper surface  24  and lower surface  22  of upper layer  20  in the area of second pad  142 . Upper surface  150  also coincides with upper surface  17  of insole  100  in the area of second pad  142 . Third pad  154  is situated entirely within lower layer  26 . Thus, lower surface  158  and upper surface  160  of third pad  154  are positioned between lower surface  28  and upper surface  30  of lower layer  26 . Further, the portion of third pad  154  which overlaps with the respective portion of second pad  142  is situated below second pad  142 . Fourth pad  156  is situated in the upper portion of lower layer  26  so that upper surface  164  of fourth pad  156  coincides with upper surface  30  of lower layer  26  in the area of fourth pad  156  and lower surface  162  of fourth pad  156  is positioned between lower surface  28  and upper surface  30  of lower layer  26 .  
         [0024]     Of course, any of pads  140 ,  142 ,  154  and  156  may be vertically positioned like pads  40  and  42  of insole  10 , that is, essentially on the bottom of the insole. Likewise, pads  40  and  42  of insole  10  may be vertically positioned as are the pads of insole  100 . At least one of pads  140 ,  142 ,  154  and  156 , or a portion thereof, has a different rebound rate than at least one other of said pads or portion thereof, the other pad or portion being horizontally distinct from the one pad or portion thereof. Otherwise, each pad may have the same or different rebound rates, depending on the desired effect of insole  100 . The elastomers and characteristics thereof used for pads  140 ,  142 ,  154  and  156  are described with respect to insole  10  above.  
         [0025]     Any of pads  140 ,  142 ,  144  and  146  may be positioned like the other pads without departing from the spirit of the invention. Further, any pad may be positioned in upper layer  20  in a manner similar to the location of third pad  154  with respect to lower layer  26 , that is, positioned below the upper surface and above the lower surface of a given layer or embedded so as to be completely encompassed by the given layer so that no portion of the pad extends vertically or horizontally outside the surfaces of that layer. In addition, any given pad or portion thereof may extend above the general level of the upper surface of the insole or below the general level of the lower surface of the insole.  
         [0026]     The third embodiment of the present invention is shown in  FIG. 9 , the inventive concept being applied to sole  200  of a shoe instead of an insole. Sole  200  is part of a shoe  202 , which also includes an insole  204  positioned above and resting on sole  200  and an upper  206  connected to sole  200  and generally positioned above sole  200 , as is standard in the art.  
         [0027]     Sole  200  has an upper surface  208  and a lower surface  210  and includes a first pad  212  positioned in an area analogous to metatarsus section  34  of insole  10  and a second pad  214  positioned rearwardly of first pad  212  in an area analogous to heel section  38  of insole  10 . First pad  212  has an upper surface  216  and a lower surface  218  and second pad  214  has upper surface  220  and a lower surface  222 . Upper surface  216  of first pad  212  coincides with upper surface  208  of sole  200  in the area of first pad  212 . Upper surface  220  of second pad  214  coincides with upper surface  208  of sole  200  in the area of second pad  214 . Lower surface  218  of first pad  212  and lower surface  222  of second pad  214  are situated between upper surface  208  and lower surface  210  of sole  200 . First pad  212  and second pad  214  have different rebound rates as described in more detail with regard to insole  10 . The elastomers and characteristics thereof used for pads  212  and  214  are described with respect to insole  10  above.  
         [0028]     The fourth embodiment of the present invention is indicated generally at  300  in  FIG. 10  and is similar to sole  200  except for the location of the pads. Sole  300  has an upper surface  308  and a lower surface  310  and includes a first pad  312  positioned in an area analogous to metatarsus section  34  of insole  10  and a second pad  314  positioned rearwardly of first pad  312  in an area analogous to heel section  38  of insole  10 . First pad  312  has an upper surface  316  and a lower surface  318  and second pad  314  has upper surface  320  and a lower surface  322 . First pad  312  and second pad  314  are embedded within sole  300 . Thus, upper surface  316  and lower surface  318  of first pad  312  and upper surface  320  and lower surface  322  of second pad  314  are all positioned between upper surface  308  and lower surface  310  of sole  300 . First pad  312  and second pad  314  have different rebound rates as described in more detail with regard to insole  10 . The elastomers and characteristics thereof used for pads  312  and  314  are described with respect to insole  10  above.  
         [0029]     Soles  200  and  300  illustrate only a pair of potential embodiments, just as insoles  10  and  100  illustrate only a pair of endless configurations. Any number of pads may be used with soles  200  and  300  without departing from the spirit of the invention. The pads of soles  200  and  300  may be positioned in any number of ways, as illustrated in regard to insoles  10  and  100  without departing from the spirit of the invention. No limitations are intended in regard to these matters. The primary key of the invention is that at least two pads have different rebound rates. Depending on the particular use, elastomers which vary the other characteristics may also be desireable. Thus, in addition to the various rebound rates, altering the hardness and/or the density will substantially improve the function of a given sole or insole.  
         [0030]     In the foregoing description, certain terms have been used for brevity, clearness, and understanding. No unnecessary limitations are to be implied therefrom beyond the requirement of the prior art because such terms are used for descriptive purposes and are intended to be broadly construed.  
         [0031]     Moreover, the description and illustration of the invention is an example and the invention is not limited to the exact details shown or described.