Insole for a sports shoe

Abstract: An inner sole (1) for a sports shoe, in particular a mountain-climbing or hiking boot, having an anatomically shaped body (2) made of plastic material, and a strengthening insert (3) embedded in the body (2); the insert (3) has a longitudinally ribbed structure, and includes a main portion (10) extending along the sole of the foot and wide enough to provide for a high degree of torsional rigidity of the inner sole, and a narrow front appendix (11) extending from the main portion (10) and connected to the main portion substantially at the metatarsus.

Description: The present invention relates to an insole for a sports shoe, in particular a hiking or mountain-climbing boot. An insole is the inner structural member of the sole assembly, to which the upper is fixed during manufacture of the boot, and to the underside of which the actual sole is then fixed, e.g. glued. Insoles are known which substantially comprise a body made of plastic material; and a metal strengthening insert embedded in the body and normally defined by a fairly narrow metal plate of constant width and extending longitudinally with respect to the body of the insole. Known insoles of the above type have several drawbacks. In particular, the torsional rigidity of the plate is poor, thus impairing comfort and safety, especially over rough ground. Moreover, being of constant flexural rigidity along the whole of its length, the insert may be excessively rigid where a certain amount of flexing is required, e.g. at the metatarsus, and excessively flexible elsewhere, thus resulting in undesired permanent deformation or breakage. US-A-5 720 118 discloses an insole having the features of the preamble of claim 1. It is an object of the present invention to provide an insole for a sports shoe, designed to eliminate the aforementioned drawbacks typically associated with known insoles of the type described above and having an improved and controlled rigidity. According to the present invention, there is provided an insole as claimed in Claim 1. In the present invention, the insert has a longitudinally ribbed structure. A preferred, non-limiting embodiment of the present invention will be described purely by way of example with reference to the accompanying drawings, in which: Figure 1 shows a partially sectioned plan view of an insole in accordance with a first embodiment of the present invention; Figure 2 shows a section along line II-II in Figure 1; Figure 3 shows a section along line III-III in Figure 1; Figure 4 shows a partially sectioned plan view of a second embodiment of the present invention; Figure 5 shows a section along line V-V in Figure 4; Figure 6 shows a partially sectioned plan view of a third embodiment of the present invention; Figure 7 shows a section along line VII-VII in Figure 6. Number 1 in Figure 1 indicates as a whole an insole for a hiking or mountain-climbing boot. Insole 1 comprises an anatomically shaped body 2 made of plastic material; and a metal insert 3 embedded in body 2. More specifically, insert 3 is defined by a steel plate having a number of longitudinal ribs 4 in turn defined by a number of projections 5 and recesses 6 forming, in cross section (Figure 3), a substantially undulated profile. Insert 3 comprises a main portion 10 similar in shape to the sole of the foot and extending from a heel portion of body 2 to the metatarsus; and a front appendix 11 extending from main portion 10, substantially at the hallux region. Front appendix 11 is narrower than main portion 10, and is connected to main portion 10 at a transition region 12 substantially located at the metatarsus. Figures 4 and 5 show an insole 20 in accordance with a further embodiment of the invention. Insole 20 differs from inner sole 1 by comprising an insert 23 symmetrical with respect to a longitudinal center line of the insert, and which may therefore be used for right- and left-boot insoles, with obvious advantages in terms of scale economy. More specifically, insert 23 comprises a main portion 24 of constant width, conveniently over a third of the maximum width of the insole, and having a tapered rear portion 25 at the heel region. The front appendix 26 is narrower than main portion 24 and decreases gradually in width from the transition region, located at the metatarsus, towards the tip of the insole sole. Insert 23 also comprises a number of longitudinal ribs 27 defined by impressions having a curved cross section with the convexity facing downwards (Figure 5). Ribs 27 are conveniently three in number, one of which extends along the center line of the insert, and the others symmetrically on opposite sides of the center rib. All the ribs extend up to a peripheral edge of the insert. Figures 6 and 7 show a third embodiment of an insole in accordance with the present invention. The Figure 6 insole, indicated 30, differs from insole 20 by comprising an insert 33 having a front appendix 34 and a rear appendix 35 of substantially the same shape; each appendix 34, 35 is tapered, and comprises substantially straight lateral edges 36 and a rounded end. In this case, too, insert 33 comprises three longitudinal ribs 37 in the form of impressions having a curved cross section with the convexity facing downwards (Figure 7), and one of which extends along the center line of the insert. All of ribs 37, however, terminate a given distance from the free edge of insert 33, so that each appendix 34, 35 comprises a substantially flat end portion 38, the flexural rigidity of which is reduced not only by being narrower but also be comprising no ribs. At each end, insert 33 also comprises a hole 39 by which to position the insert inside a mold in which to inject the plastic material defining the main body of the insole. The advantages of the insoles according to the present invention will be clear from the forgoing description. Inserts 3, 23, 33 provide for a good degree of torsional and flexural rigidity at the main portion, by virtue of the fairly large width of the main portion itself, and for greater flexibility at the front region, thus improving comfort and reducing the risk of permanent deformation or breakage of the more highly stressed portions of the insole. Moreover, the longitudinally ribbed structure of the insert provides for achieving a good degree of flexural rigidity even of fairly thin, and therefore lightweight, inserts. Clearly, changes may be made to the insoles as described herein without, however, departing from the scope of the present invention which is defined in the appended claims. In particular, the insert may be made of any suitable material, e.g. a carbon-fiber-based composite material. Moreover, the transition region between the front appendix and the main portion of the insert may be shifted slightly forwards or rearwards, depending on specific shoe design requirements; and the longitudinal ribs may be formed in any other way.

Claims: An insole (1, 20, 30) for a sports shoe, in particular a mountain-climbing or hiking boot, of the type comprising a body (2) made of plastic material, and a strengthening insert (3, 23, 33) embedded in the body (2); said insert (3, 23, 33) comprising a main portion (10, 24) extending along said body (2) from a region close to the heel of the foot to a region at the metatarsus; and an appendix (11, 26, 34) extending frontwards from said main portion (10, 24) and smaller in width than the main portion (10,24), characterized in that said insert (3, 23, 33) comprises longitudinal ribs (4, 27, 37) extending along said main portion (10, 24) and at least part of said appendix (11, 26, 34). An inner sole as claimed in Claim 1, characterized in that said insert (3, 23, 33) is made of sheet metal. An insole as claimed in Claim 1 or 2, characterized in that said ribs (4) are defined by a number of projections (5) alternating with recesses (6) and forming, in cross section, an undulated profile. An insole as claimed in Claim 1 or 2, characterized in that said ribs (27, 37) are defined by impressions having a curved section with the convexity facing downwards. An insole as claimed in any one of the foregoing Claims, characterized in that said main portion (10) of said insert (3) is similar in shape to the sole of the foot. An insole as claimed in one of Claims 1 to 4, characterized in that said insert (23, 33) is symmetrical with respect to a respective longitudinal center line. An insole as claimed in Claim 6, characterized in that said main portion (24) is of substantially constant thickness. An insole as claimed in Claim 7, characterized in that said main portion (24) is of a width equal to at least a third of the maximum width of the insole. An insole as claimed in any one of the foregoing Claims, characterized in that said insert (23, 33) comprises three said ribs (27, 37), one of which extends along a longitudinal center line of the insert. An insole as claimed in Claim 9, characterized in that said ribs (37) terminate a given distance from a peripheral edge of the insert; an end portion (38) of said appendix (34) being substantially flat.

Inventors: BIZZOTTO FIDE, BIZZOTTO, FIDE
Applicants: SCARPA CALZATURIFICIO SPA, CALZATURIFICIO S.C.A.R.P.A. S.P.A.
Application year: 1999
Main classification: A43B17
IPC codes: A43B13, A43B17