Patent Publication Number: US-7581336-B2

Title: Sole for footwear

Description:
The present invention relates to a sole for footwear. 
     BACKGROUND OF THE INVENTION 
     Feet, which are the human body&#39;s means for support and walking, have a complex structure capable of supporting the weight that bears on them both in static conditions and in dynamic conditions. 
     The complexity of this structure, dictated by the need to ensure the adaptability and flexibility required by a human being to stand upright, walk and run, requires a delicate balance, which if neglected can cause negative effects on the entire human body, such as for example excessive fatigue of the legs, lumbar pains, acquisition of an incorrect posture and/or gait, and many other muscular and spinal column disorders. 
     The shape of the sole of the foot is particularly important; due to its particular three-dimensional structure, by means of its anterior, lateral and posterior regions of the plantar surface, it constitutes the element for direct contact, also known as footprint, with the ground or with the insole of an item of footwear. 
     Accordingly, the footprint lacks the region related to the central surface, which due to the skeletal configuration of the anterior and posterior areas of the foot, which are supported by the action of the posterior tibial muscle, remains raised in an arc-like configuration, producing the so-called plantar arch. 
     The foot, as a whole, does not simply form a tripod, which would allow it to have exclusively static functions, but forms a three-dimensional architectural structure, comparable to a helix with a variable pitch, which is capable of coiling and uncoiling in accordance to the static and dynamic functions of the foot, accordingly affecting the plantar arch and therefore the shape of the footprint. 
     In order to ensure good functionality both in static conditions and during walking, said arch has a variable breadth. 
     While standing, said arch is in fact flattened in order to allow stable support, whereas while walking there is an alternation of contraction and distension of said arch, so as to achieve an effective dynamic balance. 
     The contraction or lifting of said arch and its distension are achieved respectively by means of the outward rotations, also known as supinations, and inward rotations, also known as pronations, of the calcaneum with respect to the tibia. 
     To allow this movement of the foot to yield the required results and therefore ensure the support of the human body without causing aches or fatigue thereof, the maximum and minimum breadths of the arch of the foot must be contained within very specific limits, which determine the morphological normality of the foot. 
     An excessive distension of the arch of the foot or an excessive contraction thereof may lead, moreover, to fatigue of the posterior tibial muscle, which is thus forced to contract excessively, transmitting a feeling of discomfort. 
     In order to improve the contact of the sole of the foot, plantar inserts are currently used which can be rendered more or less anatomically contoured by adding supports at the concave regions of the sole of said foot, said supports being suitable to lift passively the plantar arch, or by means of footwear correction devices, by assembling together with the plantar insert supports capable of redistributing in a targeted and case-specific manner the loads on specific points of the sole of the foot. 
     The main drawback of these known types of plantar insert is that the foot is prevented from performing certain natural and physiological movements, causing fatigue and discomfort. 
     Another drawback of known types of plantar insert relates to the fact that in most cases they are made to measure, requiring high production costs and the use of specialized labor. 
     Italian utility model No. 233568 is also known which discloses a regenerating anatomically-contoured plantar insert, in which the upper surface has a steep downward inclination in the outer region of the foot. 
     This regenerating anatomically-contoured plantar insert therefore induces an increased supination of the foot and therefore a lifting of the plantar arch of the foot, which is achieved without requiring the presence of protrusions that directly support said region of the sole of the foot. 
     However, even this solution does not solve all the drawbacks noted earlier. 
     SUMMARY OF THE INVENTION 
     The aim of the present invention is to provide a sole for footwear that allows to achieve an optimum level of comfort, reducing significantly the fatigue caused by prolonged standing or by long walks. 
     Within this aim, an object of the invention is to provide a sole for footwear that can be used both by users whose feet are within the normal morphological and functional range and by users whose feet have an excessive relaxation or contraction of the plantar arch. 
     Another object is to provide a sole that is structurally simple and has low manufacturing costs. 
     This aim and these objects, as well as others which will become better apparent hereinafter, are achieved by a sole for footwear, characterized in that it has an upper surface which, on at least part of the heel region and the plantar arch region, at its outer edge, is lower than its inner edge, the highest point of said upper surface being arranged approximately at the radiographic projection of the scapho-cuneiform joint of the foot of the user on said sole. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Further characteristics and advantages of the invention will become better apparent from the following detailed description of a particular but not exclusive embodiment thereof, illustrated by way of non-limiting example in the accompanying drawings, wherein: 
         FIG. 1  is a perspective view of a sole for footwear according to the invention, on the upper surface of which the level contour lines related to its height are shown; 
         FIG. 2  is a top view of the sole on which the level contour lines related to the height of its upper surface are shown; 
         FIGS. 3 ,  4 ,  5 ,  6 ,  7  and  8  illustrate, in views taken respectively along the lines III-III, IV-IV, V-V, VI-VI, VII-VII and VIII-VIII of  FIG. 2 , the transverse profile of the sole in various points thereof; 
         FIGS. 9 ,  10 ,  11 ,  12 ,  13 ,  14 ,  15 ,  16 ,  17 ,  18  and  19  illustrate, in views taken respectively along the lines IX-IX, X-X, XI-XI, XII-XII, XIII-XIII, XIV-XIV, XV-XV, XVI-XVI, XVII-XVII, XVIII-XVIII and XIX-XIX of  FIG. 2 , the longitudinal profile of the sole in various points thereof. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     In the examples of embodiment that follow, individual characteristics, given in relation to specific examples, may actually be interchanged with other different characteristics that exist in other examples of embodiment. 
     Moreover, it is noted that anything found to be already known during the patenting process is understood not to be claimed and to be the subject of a disclaimer. 
     With reference to the figures, the reference numeral  1  designates a sole, which has an approximately flat lower face  2 , while its upper surface  3  has, at least on part of the region of the heel  4  and of the region of the plantar arch  5 , proximate to its outer edge  6 , a lower height than it has proximate to its inner edge  7 , the expressions “outer edge” and “inner edge” being used to designate the edges that lie respectively at the outer region and at the inner region of the foot of the user. 
     The shape of the upper surface  3  of the sole  1  is clearly shown in the accompanying figures, which illustrate a sole for a European size 42 shoe; such sole can be used as a template from which the proportions are to be deduced for providing a sole that can be used with footwear of any chosen different size, preferably comprised between sizes 34 and 51. 
     The numeric values indicated hereafter in relation to the height of the various regions of the upper surface  3  with respect to the lower face  2  must be considered as indicative of the differences in height between said regions or points of the various longitudinal and transverse profiles, and the entire upper surface can be shifted vertically upward or downward by a chosen value, which is equal for the entire upper surface  3 , with respect to what has been described so far by way of example. 
     As shown in  FIG. 3 , the upper surface  3  of the sole has, proximate to its rear end  8 , a transverse profile which, starting from the inner edge  7 , has a first approximately straight portion  9  of increasing height, which is blended with a second approximately straight portion  10  which rises with a smaller inclination than the first portion. 
     Proximate to the rear end  8 , the sole therefore has, at its outer edge  6 , a height, measured starting from the lower face  2 , of approximately 2.6 centimeters, which is greater than that of its inner edge  7 , which is approximately 2.2 centimeters. 
     At the heel region  4  that is adjacent to the rear end  8  and approximately at the region of the plantar arch  5 , the sole has, at its outer edge  6 , a lower height, measured starting from the lower face  2 , than its inner edge  7 . 
     The sole  1  has, approximately at the radiographic projection of the scapho-cuneiform joint of the foot of the user on said sole, a rise  11 , which is arranged at the inner edge  7  of the sole  1 , constitutes the highest point of the upper surface  3  with respect to the lower face  2 , and is arranged at a height of approximately 2.6 centimeters with respect to the lower face  2 . 
       FIG. 4  illustrates the transverse profile of the sole  1  at the rise  11 ; said profile has, starting from the inner edge  7 , a third curved and descending portion  12 , which is blended with a fourth central portion  13 , which is approximately flat and arranged closer to the outer edge than to the inner edge and has its lowest point at a height, with respect to the lower face  2 , of approximately 2.2 centimeters; said fourth portion in turn is blended with a fifth curved portion  14 , which rises slightly up to the outer edge  6 . 
     At the plantar arch region  5 , the upper surface  3  of the sole  1  has a configuration that slopes down longitudinally toward the tip. 
       FIG. 5  illustrates the transverse profile of the sole  1  at a region of the plantar arch that is adjacent to the region of the heel  4 ; said profile has, starting from the inner edge  7 , which is arranged at a height of approximately 2.3 centimeters with respect to the lower face  2 , a sixth curved and descending portion  15 , which is blended with a seventh portion  16 , which is approximately flat and arranged closer to the outer edge than to the inner edge, its lowest point being at a height of approximately 1.8 centimeters with respect to the lower face  2 ; said seventh portion in turn is blended with an eighth portion  17 , which is curved and rises slightly up to the outer edge  6 . 
       FIG. 6  illustrates the transverse profile of the sole  1  approximately at the central region of the plantar arch; said profile has, starting from the inner edge  7 , which is arranged at a height of approximately 1.9 centimeters with respect to the lower face  2 , a ninth curved and descending portion  18 , which is blended with a tenth portion  19 , which is approximately flat and arranged closer to the outer edge than to the inner edge, its lowest point being located at a height of approximately 1.5 centimeters with respect to the lower face  2 ; said tenth portion in turn is blended with an eleventh portion  20 , which is curved and rises slightly up to the outer edge  6 . 
     The transverse profile of the sole  1 , approximately in the region of the plantar arch that is adjacent to the metatarsal region  21 , is shown in  FIG. 7 , which shows that it is constituted by a twelfth curved portion  22 , which descends starting from the inner edge  7 , at which it has a height of approximately 1.5 centimeters with respect to the lower face  2 . 
     A thirteenth portion  23  is blended with the twelfth portion, is approximately flat and lies closer to the inner edge than to the outer edge, its lowest point being at a height of approximately 1.2 centimeters with respect to the base  2 ; said thirteenth portion in turn is blended with a fourteenth portion  24 , which is curved and rises slightly up to the outer edge  6 , at which it has approximately the same height as the inner edge  7 . 
     The upper surface  3  of the sole  1  has, approximately in the metatarsal region, proximate to its outer edge, a height, measured starting from the lower face  2 , that is greater than the height of its inner edge. 
       FIG. 8  is a view of the transverse profile of the upper surface  3  of the sole  1  at the metatarsal region  21 ; said profile has, starting from the inner edge  7 , which is arranged at a height of approximately 0.5 centimeters with respect to the lower face  2 , a fifteenth curved and descending portion  25 , which is blended with a sixteenth approximately flat portion  26 , which lies closer to the inner edge than to the outer edge and has its lowest point at a height of approximately 0.4 centimeters with respect to the lower face  2 ; said sixteenth portion in turn is blended with a seventeenth curved portion  27 , which rises up to the outer edge  6 , at which it has a height of approximately 0.7 centimeters with respect to the base  2 . 
       FIGS. 9 to 19  illustrate the longitudinal profile of the sole  1  along a corresponding number of longitudinal sectional planes, which show that the upper surface  3  has a slightly concave shape at the metatarsal region  21 . 
     In the region of the plantar arch  5 , the longitudinal profile of the sole  1  instead has an inclined shape, which rises toward the heel region  4 ; the slope of the longitudinal profile in this region is greater proximate to the inner edge  7  of the sole  1  and decreases as one moves toward the outer edge  6 . 
       FIG. 16  illustrates, at the rear end  8  of the sole  1 , a cavity  28 , which can also be seen in  FIG. 8  and is arranged at the inner edge  7 . 
     The shape of the upper surface  3  of the sole  1  forces the foot of the user to perform a slight outward rotation of the calcaneum, also known as calcanear supination; accordingly, the foot acquires a posture that accompanies it dynamically in the natural helical coiling and uncoiling actions, facilitating it when standing upright for prolonged periods and preparing it appropriately to cope with dynamic conditions in walking. 
     In this manner, the posterior tibial muscle is positioned in an optimum manner, since it has neither an excessive contraction nor an excessive relaxation; this configuration therefore allows to prevent said muscle from being fatigued during long periods spent standing upright or walking. 
     It has thus been found that the invention has achieved the intended aim and objects, a sole having been provided which allows to obtain an optimum level of comfort, reducing significantly the fatigue arising from prolonged standing upright or from long walks. 
     Another object achieved by the invention is to be usable both by users whose feet are within the normal morphological and functional range and by users whose feet have an excessive relaxation or contraction of the plantar arch. 
     Another object achieved by the invention is to require no manufacturing to measure, therefore allowing a reduction of production costs. 
     The invention is of course susceptible of numerous modifications and variations, all of which are within the scope of the appended claims. 
     Thus, for example, it is possible to provide the sole  1  according to a stratified structure; in an advantageous but not unique embodiment, the sole is constituted by a bottom on which an insole is rigidly superimposed, the upper surface of the resulting sole being shaped according to what is described and illustrated in the accompanying drawings. 
     The materials used, as well as the dimensions that constitute the individual components of the invention, may of course be more pertinent according to the specific requirements. 
     The various means for performing certain different functions need not certainly coexist only in the illustrated embodiment but can be present per se in many embodiments, including ones that are not illustrated. 
     The characteristics indicated as advantageous, convenient or the like may also be omitted or be replaced by equivalents. 
     The disclosures in Italian Patent Application No. TV2004A000123, from which this application claims priority, are incorporated herein by reference.