Patent Publication Number: US-6662474-B2

Title: Buttress for shoes

Description:
BACKGROUND OF THE INVENTION 
     1. Technical Field of the Invention 
     The present invention relates to a buttress for shoes. 
     The buttress of the present invention is in particular destined to sports shoes and it has orthopaedic aims. 
     2. Prior Art 
     As is well known, buttresses are placed in the heel of shoes to enhance their sturdiness and at the same time assure a greater stability of the foot. 
     Buttresses in use today have a horse-shoe planar development, and nearly all have a growing height from the front edges towards the centre of the rear area. The need to assure good stability to the foot, however, sometimes clashes with particular physical needs. 
     The Achilles heel area can be subject to different pathologies and injuries. For instance, in particular—but not only—in the sporting field, tendinitis, bursitis, and even rupture of the Achilles heel, which may require surgery to heal, are a very frequent occurrence. 
     Persons suffering from said pathologies undergo varying measures of discomfort when they have to use shoes with traditional rigid buttresses, in particular when they participate in sporting activities. 
     In addition, such pathologies are sharply more frequent in athletes, in particular professional ones, who subject the Achilles tendon to greater stresses and who at the same time cannot avoid taking part in sporting activities. 
     Over the years, some solutions have been developed to try solving said problem. 
     A first solution is proposed, for instance, by patent DE 2830398, which discloses a buttress having globally traditional shape, but provided in correspondence with the area of origin of the Achilles heel with a U-shaped cavity closed with an elastic material. A second solution, disclosed in patent DE 4316228, provides for the buttress to have two lateral portions joined by a thin band of material around the base of the heel. 
     Both described prior art solutions, however, have drawbacks. 
     In regard to the first solution, wherein the buttress has a U-shaped cavity closed by a soft material, it is useful only if the lesion of the Achilles heel is located centrally on the tendon. 
     If the lesion is instead located laterally relative to the tendon (which is a very frequent occurrence) it is continually stressed by the rigid part of the buttress, with the risk of further aggravation. On the other hand, the cavity cannot be made too ample, or else the buttress would lose the characteristics of sturdiness which constitute the primary aim of its usage. 
     In regard to the second described solution, it discloses, rather than a buttress, a lateral protection system of the heel, lacking the characteristics of a buttress. 
     SUMMARY OF THE INVENTION 
     In this situation, the technical task constituting the basis for the present invention is to obtain a buttress for shoes that overcomes the aforementioned drawbacks. 
     In particular, a technical task of the present invention is to obtain a buttress for shoes able to be used also by persons suffering from Achilles heel pathologies, without having to forego the foot stability provided by traditional buttresses. 
     The specified technical task and the indicated aims are substantially achieved by a buttress for shoes, as described in the accompanying claims. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Further characteristics and advantages of the present invention shall become more readily apparent from the detailed description of a preferred, but not exclusive embodiment of a buttress for shoes, illustrated in the accompanying drawings, in which: 
     FIG. 1 is a lateral elevation view of a buttress according to the present invention; 
     FIG. 2 is a perspective view of a buttress of FIG. 1 with some parts drawn in see-through mode, the better to highlight others; 
     FIG. 3 is a bottom view of the buttress of FIG. 1 in operative condition; 
     FIG. 4 shows a planar development of the buttress of FIG. 1; 
     FIG. 5 is a partially sectioned view according to the trace V—V of FIG. 4; 
     FIG. 6 shows a buttress according to the present invention mounted internally to the heel of a shoe; 
     FIG. 7 shoes a buttress according to the present invention mounted externally to the heel of a shoe; 
     FIG. 8 shows a second embodiment of a buttress according to the present invention. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     With reference to the aforementioned figures, the reference number  1  globally indicates a buttress for shoes according to the present invention. 
     The buttress  1  has, if observed in plan view, a horse-shoe shape, in which an inner part  2  and an outer part  3  can be identified. 
     The buttress  1  comprises a locking portion  4  and a yielding portion  5  positioned above the locking portion  4  and fastened thereto. 
     The locking portion  4  which is, like the buttress  1 , horseshoe-shaped if seen in plan view, has a rear area  6  whereto are joined the two lateral areas  7 . 
     The rear area  6  is integral at the two sides with each of the lateral areas  7  which are substantially opposite each other. 
     The locking portion  4  has a substantially planar lower profile  8  and an upper profile  9  jointed to the lower profile  8  in correspondence with a front edge  10  of the lateral areas  7 . 
     Said jointing can be obtained with more or less accentuated curvature depending on design preferences. 
     The upper profile  9  has at least an area of first coupling  11  in which from the locking portion  4  a plurality of appendages  12  project substantially upwards. Different embodiments of the appendages  12  are provided: some in which the appendages  12  have a curvilinear profile, others with different profiles such as a saw tooth, as well as some in which the appendages  12  narrow from the base towards the summit, and others in which, on the contrary, they widen from the base upwards. 
     In the case illustrated in the accompanying figures, the appendages  12  have a curvilinear profile and become narrower from the base towards the summit (FIG.  4 ). 
     The height of the appendages  12  can be constant, but, preferably, it is variable and it is greater the closer the appendages  12  are to the centre of the rear area  6 . 
     The yielding portion  5  has lesser rigidity than the locking portion  4 , with respect to which it has a more elastic behaviour. 
     The yielding portion  5  has a lower profile  13  whereon develops at least an area of second coupling  14  with substantially complementary shape to the area of first coupling  11 . 
     In correspondence with the area of second coupling  14 , also the yielding portion  5  has a plurality of appendages  15 , in this case developing substantially downwards, and such as perfectly to fit in the spaces between the appendages  12  of the locking portion  4 . 
     The area of second coupling  14  is coupled to the area of first coupling  11  of the upper profile  9  of the locking portion  4 , whereto it is integrally fastened, in such a way that the combination of the two portions  4 ,  5  gives rise to a buttress  1  of substantially traditional shape. 
     In the embodiment illustrated in FIGS. 1 through 5, the area of first coupling  11  develops along the upper profile  9  substantially only in correspondence with the rear area  6 , only marginally involving the two lateral areas  7 . 
     In the embodiment shown in FIG. 8, the area of first coupling  11  develops instead along the upper profile  9  in correspondence both with the rear area  6  and with the two lateral areas  7  reaching the front edge thereof. 
     It is also possible to envisage embodiments which are intermediate between the two described above. 
     Advantageously, the locking portion  4  has, in correspondence with the rear area  6 , a decreasing average height towards the centre of the rear area  6  itself, whilst the yielding area  5  has increasing height from the sides towards the centre. 
     Globally in the illustrated embodiments, the buttress  1  has an increasing height from the front edges  10  towards the centre of the rear area  6  which is destined to be placed in correspondence with the heel, but this must not be taken as binding. 
     The buttress  1  further comprises at least a tab  16  fastened to the base of the locking area  4  to secure the buttress  1  to a shoe. 
     Said tab  16  can be bent from a first position in which it lies substantially on the continuation of the locking portion  4  (FIGS. 1-5) to a second position in which it extends substantially horizontally towards the interior of the buttress  1  itself (FIGS.  6  and  7 ). 
     In the preferred embodiment the tab  16  and the locking portion  4  constitute a single body. 
     The facilitate the bending, the tab  16  has a profile at least partially saw tooth shaped, and between the base of the locking portion  4  and the tab  16 , on the inner face of the locking portion  4  itself, a groove  17  is obtained. 
     The materials constituting the locking portion  4  and the yielding portion  5  can be of any kind so long as they meet the aforesaid conditions of rigidity. 
     Advantageously, said materials can both be polymeric with different chemical compositions to differentiate their respective rigidity. 
     The union between the locking portion  4  and the yielding portion  5  (FIG. 4) can be obtained in any way. 
     If both portions  4 ,  5  are made of polymeric materials, their union can be obtained during the hot moulding of the buttress  1 , injecting in succession the materials constituting the two portions  4 ,  5  into the same mould. 
     The total thickness of the buttress  1  decreases from the bottom to the top, as shown in FIG.  2 . 
     As FIGS. 6 and 7 show, the buttress  1  of the present invention can be mounted on a shoe  18  indifferently inside or outside the shoe. 
     In known manners the overall shape of the buttress  1  may be slightly different, depending on whether it is destined to be inserted in a shoe  18  for a right or left foot, the better to adapt to the anatomical conformation of the foot. 
     When a person uses a shoe  18  provided with the buttress  1  of the present invention, the latter prevents lateral movements of the heel of the foot mainly thanks to the contribution of the locking portion  4  and, in particular, of the lateral areas  7  thereof. 
     The movements of the ankle instead are not hampered by the buttress  1 , thanks to the yielding portion  5 . 
     The particular shape of the two portions guarantees an increasing flexibility of the buttress  1  from the bottom to the top. 
     Moreover, the greater flexibility is in correspondence with the area of the Achilles heel, where the mean height of the yielding portion is greatest. 
     The present invention achieves important advantages. 
     A person using a shoe fitted with the buttress simultaneously enjoys both a greater transverse rigidity which guarantees the foot&#39;s stability, and a soft support for the Achilles heel. In particular, therefore, the buttress of the present invention is suitable to be used also by persons suffering from Achilles heel pathologies, without having to forego the foot stability provided by traditional buttress. 
     Moreover, the buttress of the present invention is particularly well suited for sports shoes. 
     It should further be noted that the present invention is relatively easy to manufacture and that the cost connected with embodying the invention is not very high. 
     The invention thus conceived can be subject to numerous modifications and variations, without thereby departing from the scope of the inventive concept. All components can be replaced with technically equivalent elements and in practice all materials employed, as well as the shapes and the dimensions of the various parts, may be any depending on requirements.