Abstract:
An insole designed for supporting a foot after the insole is inserted in a shoe and which abuts a sole section of the shoe includes an integral plastic material forming a flexible planar base layer out of which numerous resilient studs arise. The insole is easily manufactured and provides a comfortable feeling. The planar base layer is designed as a contact surface for the foot. The studs are designed to extend from the base layer to the sole section of the shoe, and are shaped of different heights so that upon weight-loading by the foot the flexible planar base layer is deformed so as to conform with the shape of the underside of the foot as a three-dimensionally shaped footbed.

Description:
FIELD OF THE INVENTION 
       [0001]    The present invention relates to an insole designed for supporting a foot after the insole is inserted into a shoe so as to abut a sole section of said shoe, where the insole comprises an integral plastic material forming a flexible planar base layer out of which numerous resilient studs arise. In addition, the present invention furthermore relates to a shoe comprising a removable insole of the described type. 
       BACKGROUND 
       [0002]    Removable insoles for shoes are well-known. They consist of different material and are in many cases pre-shaped by thermoforming (e.g. EVA (ethyl vinyl acetate) foam) or forming in a closed mold (e.g. PU (polyurethane) foam). They form a footbed within the shoe the sole section of which may or may not sufficiently be shaped so as to form a footbed. Insoles of this type have a defined three-dimensional shaping so that many types have to be fabricated in order to fit customer&#39;s needs. Insoles of this type may extend over the whole length of the foot or may be designed to support only a part of the foot, e. g. the heel portion or a forefoot portion. 
         [0003]    There are known insoles provided with a great number of resilient studs arising out of a flexible planar base layer so that the essential parts of the insole consist of an integral plastic material manufactured by injection molding. An example of an insole of this kind is described by US 2010/0175275 A1, the complete contents of which is herein incorporated by reference. The numerous resilient studs serve for providing a massaging and reflexology system by contacting the sole of the foot of a person by means of the top portions of the studs. Simultaneously, a shock absorption is achieved by means of the resilient studs. The top surface of the insole formed by the top portions of the studs may be contoured to generally match the contour of a human foot such that the massaging and reflexology system is maintained in substantially continuous contact with at least a portion of the bottom of user&#39;s foot. In this manner the interactive effects of massaging, shock absorption, muscle stimulation and blood circulation may be better administered to the wearer or user&#39;s foot. These types of insoles are usable only for users desiring a massaging or reflexology effect and who are prepared to tolerate the intensive punctual contacts between the insole and the sole of the foot which punctiform contact provides intensive stimuli to the foot which may be sensed as less comfortable, especially when the studs have a high hardness. U.S. 2010/0175275 Al discloses top portions of the studs which are cup-shaped thereby enlarging the contact area between the insole and the user&#39;s foot. 
         [0004]    GB 2 418 129 A, the complete contents of which are herein incorporated by reference, discloses an impact absorbing insole having an upper layer of a woven fabric surface which provides the surface of contact for the user&#39;s foot. The lower layer comprises a cell membrane structure where the cells all have the same size and contain a chemically inert gel or fluid of sufficient viscosity to provide a cushioned effect when compressed. Which such a construction a shaping of the insole for forming a footbed must be made at the top layer in the above-mentioned conventional way. 
       SUMMARY 
       [0005]    It is an object of the present invention to provide an insole of the above-mentioned kind which may be produced in an easy manner and provides a kind of footbed and a comfortable feeling. 
         [0006]    According to the present invention, the insole is designed (configured) for supporting a foot after the insole is inserted in a shoe so as to abut a sole section of the shoe. The insole includes an integral plastic material forming a flexible planar base layer out of which numerous resilient studs arise. The planar base layer is designed to contact the surface of the foot. The studs are designed to extend from the base layer to the sole section of the shoe. The studs are shaped of different heights so that upon weight-loading by the foot the flexible planar base layer is deformed so as to conform with the shape of the underside of the foot as a three-dimensionally shaped footbed. 
         [0007]    According to the present invention the studs are not used for massaging and reflexology, but instead for easily forming a footbed for the user&#39;s foot upon weight-loading. For this purpose the studs are made of different heights so that without weight-loading the insole contacts the sole section of the shoe only with some of the studs which have a relatively large height. In this state, the planar base layer remains planar. Upon weight-loading, the studs of smaller height are pressed against the sole section of the shoe so that the base layer is deformed to allow the smaller studs to contact the sole section of the shoe. The distribution of height of the studs is chosen such that by the deformation of the base layer a suitable footbed is formed by the base layer which serves as a contact surface for the foot. It should be noted that the base layer need not have a direct contact to the foot but may be covered with a flexible cover layer such as a textile, leather or other material which preferably has skin-friendly properties. The cover layer, however, does not substantially influence the deformation of the planar base layer which deformation is determined by the distribution and heights of the studs at the underside of the insole. Therefore, the base layer can be manufactured as a planar layer and nevertheless, form a footbed when the weight of the user is loaded onto the insole. Due to the studs at the underside, the insole may be manufactured with less material compared with an insole made of the same material and shaped to form a footbed of a conventional type. Due to the studs there is a plurality of interspaces between the studs for which no material is needed. In addition, the studs have elastic properties and produce a progressive spring characteristic since upon increasing weight loading more and more studs contact the sole section of the shoe thereby contributing to the overall spring strength of the insole. Due to the studs, the insole of the present invention may be produced with about 60% of the material, and thus of the weight, needed for an insole forming a footbed from the same fully shaped material. Due to the studs the insole according to the present invention has the capacity of adapting the deformation to the individual foot upon weight loading. 
         [0008]    The studs may be distributed over the whole length of the insole. For some purposes it may be preferred to provide studs at the underside of the insole only over a part of the length of the insole, e. g. to provide only a heel portion, a heel and plantar arch portion and/or a toe portion with studs allowing the deformation of the base layer so as to form a footbed. For some purposes it may be preferred that the insole according the present invention extends only over a part of the length of the foot so as to support only a part of the foot length, such as the heel portion, the heel and plantar arch portion and/or the toe portion. 
         [0009]    In a preferred embodiment of the present invention the hardness of the material from which the base layer and the studs are formed may lie between 30 and 50 Shore 00, more preferred between 33 and 45 Shore 00 and even more preferred between 35 and 40 Shore 00. The material, therefore, may be a comparably soft material differing in hardness from the material used for studs for massaging and reflexology where the hardness lies between 80 and 100 Shore 00 and even for a soft massaging sandal above 50 Shore 00. 
         [0010]    In a preferred embodiment the insole extends over the whole length of the foot and there are studs of small height in the middle of a heel portion and of a toe portion of the insole and studs of greater heights are provided at the edge of the heel portion as well as in an intermediate portion between the heel portion and the toe portion. The intermediate portion will preferably be an instep portion of the insole. 
         [0011]    For the sake of easy manufacturing the studs are preferably massive studs, i.e. without a hollow portion. 
         [0012]    The studs are preferably designed for widening their diameter when being compressed under weight-load. The reduction of height due to the elastic weight-loading may, therefore, result in a corresponding widening of the diameter so that the studs extend into intermediate spaces between the studs. 
         [0013]    In a preferred embodiment of the invention, a number of ventilation holes are positioned within the base layer in interspaces between the studs. The widening of the studs under weight-load reduces the interspace between the studs so that air may be pressed through the ventilation holes from the underside of the sole onto the lower surface of the foot exerting the weight-loading onto the insole. 
         [0014]    A preferred material for the insole is a gel, especially a polyurethane gel. In a preferred embodiment the polyurethane gel may have a specific weight between 0.6 and 1.1 g/cm 3 . A suitable gel may be sticky so that in a preferred embodiment the gel is covered by a film of a non-adhesive material which again may be a polyurethane being, however, selected so as to be non-adhesive and non-sticky. 
     
    
     
       DESCRIPTION OF THE DRAWINGS 
         [0015]    The invention will be described in more detail with reference to the accompanying drawing in which 
           [0016]      FIG. 1  is a perspective view of the underside of a first embodiment of an insole; 
           [0017]      FIG. 2  is a side view of the insole of  FIG. 1 ; 
           [0018]      FIG. 3  is a view from below the insole of  FIG. 1  showing an exemplary distribution of the studs; 
           [0019]      FIG. 4  is a perspective view of the underside of a second embodiment of an insole; 
           [0020]      FIG. 5  is a view from below the insole of  FIG. 4 ; 
           [0021]      FIG. 6  is a schematic diagram showing the deformation of the studs when loaded with body weight; 
           [0022]      FIG. 7  is a similar diagram to  FIG. 6  highlighting a ventilation effect through ventilation holes; 
           [0023]      FIG. 8  is a perspective view of the underside of an embodiment of an insole having studs only in a heel section; 
           [0024]      FIG. 9  is a perspective view of the underside of an embodiment of an insole having studs only in the heel and plantar arch section; 
           [0025]      FIG. 10  is a perspective view of the underside of an insole extending only over the heel section of a foot length. 
       
    
    
     DETAILED DESCRIPTION 
       [0026]    The embodiment of  FIGS. 1 to 3  is an integral insole from a plastic material having or consisting of a thin planar base layer  1  and a plurality of studs  2  on the underside of the base layer  1 . The upper side of the base layer is manufactured as a flat surface  3  serving as a contact surface to a user&#39;s foot. For this purpose the integral insole made from plastic material according to  FIGS. 1 to 3  may be provided with a cover layer on the upper side of the flat surface  3 . 
         [0027]    Furthermore, the material of the insole forming the base layer  1  and the studs  2  may be encased by a film of a similar material as the base layer  1  and the studs  2  but modified so as to be non-sticky or non-adhesive. It is understood that a cover layer for the flat surface  3  may be applied on the encasing film of base layer  1  and studs  2  when such an encasing film is used. 
         [0028]    The insole can be produced by casting the material in liquid form into a casting mold having deeper cavities in the form of the studs  2  and in between a small flat cavity for the base layer. The cavities may be lined with the non-sticky film in a well-known manner, e.g., by applying vacuum to a film, by coating, or by applying a release agent. Then, the liquid material is cast and allowed to pour in the mold. After pouring, the mold may be covered with the cover layer which may be for example a textile, leather or microfiber material which thereby is fixedly adhered to the material of the insole during the curing of the material in the mold and serves as a contact surface. 
         [0029]    As illustrated in the drawings the studs  2  at the underside of the base layer  1  have different heights. They may have a cylindrical shape with a rounded tip. The cross-section of the cylindrical shape is circular. The diameter of the studs within the cylindrical portion corresponds essentially to the height of the respective studs. It can be seen that there are higher studs  2   a  at the edge of a heel portion  4  of the insole. The studs  2   a  at the edge are higher and have a greater diameter than studs  2   b  in the middle of the heel portion  4 . 
         [0030]    At the other end of the insole, namely in a toe portion  5 , studs  2   c  can be even smaller than the studs  2   b  in the middle of the heel portion. Between the toe portion  5  and the heel portion  4  there is an intermediate portion  6  showing higher studs  2   d  which in an arch plantar portion of the insole can be even higher than the studs  2   a  at the edge of the heel portion. The studs  2   d  at the lateral edge of the intermediate portion  6  may be about the same size as the studs  2   a  at the edge of the heel portion  4 . The intermediate portion  6  establishes an instep portion of the insole being designed to (configured to) contact the instep portion of the user&#39;s foot. 
         [0031]    As  FIGS. 1 and 2  illustrate, the insole as manufactured will contact a support layer, like the sole section of a shoe into which the insole may have been inserted, only with the tips of the relatively highest studs  2 . In this state the base layer  1  remains flat and planar. The studs are directed to the support surface like the sole section of a shoe. If the user exerts weight-load on the insole, the insole will contact the sole section of the shoe with more of or generally all of the studs of different heights. Thereby, the base layer  1  will be deformed in accordance with the distribution of the studs  2  of different heights. The distribution of the studs  2  is selected so that the base layer is deformed to a footbed shape bedding the user&#39;s foot in a comfortable way. 
         [0032]    In the embodiment, the insole only contacts the support surface, namely the sole section of a shoe, through the studs  2  so that there is no direct contact of portions of the base layer to the sole section of the shoe. 
         [0033]      FIG. 3  illustrates an exemplary distribution of studs  2  over the whole surface of the underside of the base layer  1 . Since the heights of the studs  2  are essentially equal their diameter in the embodiment, it can be seen even from  FIG. 3  where the studs of higher height are positioned. 
         [0034]    It should be noted that the embodiment according to which the height equals the diameter of the studs  2  may be varied, for example, in the toe portion  5 , where the diameter can be different and may equal twice the height of the studs since the studs can be made very low in the toe portion  5 . 
         [0035]    The second embodiment of  FIGS. 4 and 5  shows an insole produced according to the same principle, however fitted with a somewhat thicker base layer  1  which still does not exceed  3  mm and from which the studs  2  arise. Again the heights of the studs  2  are distributed so as to form a footbed when the insole is loaded with the user&#39;s body weight. 
         [0036]      FIG. 6  depicts the influence of the body weight transmitted by the user&#39;s foot  7 . There are shown the base layer  1  with the contour of studs  2  in the state as manufactured, i. e. without weight-load. There is a large interspace  8  between the studs  2 . When the weight pressure is exerted as indicated by arrows in  FIG. 6  the studs will be compressed against the sole portion of a shoe and thereby be deformed as indicated at  2 ′. Thereby, the interspaces  8 ′ are heavily reduced in size. Simultaneously the contact surface  3 ′ of the base layer  1  being in pressure contact with the sole portion of foot  7  will adapt a contour corresponding to the contour of the sole portion of the foot  7  by different compression rates of the studs  2 ′. 
         [0037]    In the embodiment of  FIG. 7  the base layer  1  is provided with ventilation holes  9  which are through-holes connecting the interspace  8  between the studs  2  with the flat surface  3  of the base layer, i. e. with the underside of foot  7  when the insole is loaded by the weight pressure through the foot  7 . Upon the weight-loading the same deformation of the studs  2  into studs  2 ′ as illustrated in  FIG. 6  occur. The diminished interspace  8 ′ between the studs  2 ′ squeezes out air from the interspace  8 ′ through the ventilation holes  9 ′ so that the sole portion of the foot  7  is ventilated upon each weight-loading of the insole during walking, running or standing. 
         [0038]    Due to the large number of studs  2  there is a considerable squeezing out of air through the ventilation holes  9 . The effect can be enhanced by providing a seal edge at the outer contour of the insole whereby the interspaces  8  between the studs  2  as a hole are sealed against the ambiance so that a lateral squeezing out of air from the weight-loaded insole is prevented and the air is forced through the ventilation holes  9 . The sealing edge can have the form of a small lip so that it has no considerable influence on the resilient deformation of the studs  2  upon weight-loading. 
         [0039]     The insole of the present invention can be manufactured with a planar flat base layer  1  which is deformed upon applying weight pressure so as to adapt to the shape of the foot  7  exerting the weight pressure and thus forming a kind of footbed. 
         [0040]      FIG. 8  shows a modification of the insole which is similar to the insole of  FIG. 1  in the heel portion  4  so that studs  2  at the underside provide a shaping of a footbed upon weight loading as described above. However, the other parts or sections of the insole which is designed to extend over the whole foot length are without studs  2  so there is a support with studs  2  only at the heel region whereas the insole consists only of the base layer  1  in the other portions. 
         [0041]    A further modification of the insole which is similar to the embodiment of  FIG. 1  is shown in  FIG. 9 . The insole has studs  2  at the underside in the heel portion  4  and the intermediate portion  6  including the arch plantar portion. The distribution of the studs with different heights may be the same as described for the previous embodiments. Again the insole is designed to extend over the whole length of the foot but has studs  2  only in the heel portion  4  and the intermediate portion  6  and, e.g., not in the forefoot portion including the toe portion  5 . 
         [0042]    It should be noted that all embodiments of  FIGS. 1 to 9  show insoles with base layers  1  extending over the whole length of the foot  7  (or of the shoe) and have grooves or simples lines allowing to shorten the length of the insole so as to match to the length of foot  7  or shoe for the individual application. 
         [0043]      FIG. 10  shows an example for an insole according the present invention which does not extend over the whole length of the foot  7  but instead only over a certain portion, namely the heel portion  4  in the embodiment of  FIG. 10 . The insole according to this embodiment has a similar distribution of studs  2  at the underside as the embodiment of  FIG. 1  so that a footbed is formed upon weight loading by the heel of a foot  7 . It is clear for people skilled in the art that in the same way insoles may be provided for which extend over other portions of the foot length, e.g. the arch plantar portion and/or a forefoot portion. The support of a forefoot portion may especially be suited for higher heel shoes which result in a principal weight load in the forefoot or toe portion of the foot  7 . 
         [0044]    An insole extending only over a part of the length of the foot  7  may be protected against shifting or slipping within the shoe by being manufactured from a sticky material or by applying pads of sticky material to the underside of the insole, e.g., to the tips of the studs  2 , or to the contact surface  3  of the base layer  1  for fixing the insole to the foot  7 . Of course, other fixations, e. g. mechanical fixations by lateral extensions, may be used to form fit with corresponding lateral recesses of the shoe.