WO2017145134A1

WO2017145134A1 - A sole for footwear

Info

Publication number: WO2017145134A1
Application number: PCT/IB2017/051140
Authority: WO
Inventors: Alberto Del Biondi; Alessio Rizzi
Original assignee: Alberto Del Biondi S.P.A.
Priority date: 2016-02-25
Filing date: 2017-02-27
Publication date: 2017-08-31
Also published as: ITUB20161048A1

Abstract

A sole for footwear comprising a main portion and at least one insert of a material which has greater resilience than the main portion. The forefoot zone and mid-foot zone of the main portion both have tread surfaces which are peripherally delimited by a respective internal and external side of the sole. The sole is affected in at least one of the forefoot zone and/or mid-foot zone by at least one recess which extends transversely relative to the toe/heel direction. The insert is at least partially received in the recess and extends so as to affect substantially the whole of the transverse extent of the tread surface of the sole and has a configuration tapered from the external side up to affecting the internal side of the sole.

Description

A sole for footwear

DESCRIPTION

The invention relates to a sole for footwear of the type including the features set out in the preamble of the main claim .

It is known that the human foot may have different shapes. In relation to the metatarsal/phalangeal area of the foot, there are defined, for example, the shapes of the Egyptian foot, Greek foot and square or Roman foot, which are connected with the extension and relative position of the toes with respect to the big toe. Typically, these different shapes involve different motilities of the foot during walking. In order to comply with this requirement, therefore, it would be necessary to use specific items of footwear with different soles for different feet, which is to a great extent impossible. Soles including those characteristics are known, for example, from EP395538.

The invention described in EP395538 is aimed at improving the flexibility of the sole and the shock-absorbing effect thereof during sporting use of the item of footwear, in particular when practising golf, by applying soft wedge-like inserts to the sole which extend transversely over an extent which is slightly greater than half of the sole itself and which are positioned in the mid-outer portion of the sole. Furthermore, there is obtained the result of better adaptation to all the different shapes of feet, using a plurality of inserts which involve both the forefoot zone and the mid-foot zone.

An additional example of a sole is described in US 2011/00072685, which relates to an item of footwear in which there is provided a boomerang-like insert. The insert is produced from a silicone rubber in order to provide greater shock- absorbency in the metatarsal zone.

However, the effect produced is unsuitable for use for items of footwear for daily use because the deformability of the sole does not compensate sufficiently for the combined deformations of torsion and flexion which are produced during walking.

In addition to the above-mentioned disadvantage, there are not taken into account the different requirements in terms of posture and structure which result from the different morphological shapes of the foot.

The technical problem addressed by the present invention is to provide a sole for items of footwear which is structurally and functionally configured to overcome one or more of the disadvantages set out above with reference to the cited prior art.

The invention is based on the observation of the behaviour of feet of different shapes during walking and has the main technical effect of promoting the so-called "helical effect" of the foot at the point of greatest stress, which is the point approximately located at the metatarsal/phalangeal articulation, between the forefoot and mid-foot, in which combined movements of torsion and flexion are encountered during walking.

In the context of the above-mentioned problem, a main object of the invention is to develop a sole which is suitable for feet of different morphologies and which is capable of optimizing the comfort during walking.

This problem is solved and this object is achieved by the present invention by means of a device which is constructed in accordance with the appended claims.

The features and advantages of the invention will be better appreciated from the detailed description of two embodiments thereof which are illustrated by way of non-limiting example with reference to the appended drawings, in which :

- Figure 1 is a schematic top view of a sole for footwear,

- Figure 2a is a side view of the sole for footwear in accordance with the section II,

- Figure 2b is a detailed view in relation to an insert of Figure 2a,

- Figure 2c is a detailed view of Figure 2b without the insert,

- Figure 3a is a perspective view of the sole for footwear and of a portion of the footwear having the insert partially sunk in the sole,

- Figure 3b is a perspective view of the sole for footwear and of a portion of the footwear having the insert in view.

In Figures 1 to 3b, there is generally designated 1 a sole for footwear comprising a main portion 4 of relatively rigid material with respect to at least one insert 10 of relatively resilient material, wherein the reference to rigidity or resilience is made in relative terms between the two above-mentioned components. That is to say that the material which constitutes the main portion 4 of the sole 1 is more rigid than the material of the insert 10.

The main portion 4 extends in a toe/heel direction X with identification of a respective forefoot zone 2, mid-foot zone 3 and rear-foot zone 3' which are contiguous in the direction X. All the above-mentioned zones and in particular the forefoot zone 2 and mid-foot zone 3 have respective tread surfaces 5, 6 (see Figures 1, 3a and 3b).

Preferably, the tread surfaces 5, 6 are peripherally delimited by a respective internal and external side 7, 8 of the sole 1.

It is important to note that, during the normal walking movement carried out at a walking speed of approximately 82 m/min., the diagram of the vertical forces, which are applied in an orthogonal manner to a bearing plane for the foot which carries out the step, has two peaks which are separated by a depression. The first peak (of the value of approximately 110% of the body weight) occurs at the start of the intermediate support in response to the events of acceptance of the load : the centre of gravity is lowered increasing the effects of acceleration of the body weight. The depression (of approximately 80% of the body weight) identifies the final phase of the intermediate support and is generated by the centre of gravity being lifted during forward rotation of the foot which is attached to the ground. Finally, the second peak of the vertical forces occurs at the end of the terminal support during a new acceleration phase in a downward direction and at the same time a lowering of the centre of gravity. The duration and extent of the above-mentioned phases which are known to a person skilled in the art vary in accordance with the velocity of the walking by increasing the maximum value of the first peak in the case of running and increasing the extent of the depression in the case of slow walking.

These vertical forces determine flexion phases of the foot during the passage from the start of the intermediate support, when a maximum load acts on zones of the rear foot (in particular on the heel), to the following terminal phase of the intermediate support, when the load acts only on a foot in complete support, to the final phase of the terminal support, when another maximum load acts on zones of the forefoot (in particular on the first, second and third phalanxes).

In addition to those main forces, during walking there are produced lesser forces (though non-negligible) on the foot which are called horizontal shear forces having vectorial components which are parallel with the bearing surface of the foot itself. In particular, the forces applied according to vectors parallel with the sagittal plane of the user who is walking are defined as anterior-posterior shear forces, while those applied according to the vectors parallel with the frontal plane of the user are defined as medio-lateral shear forces.

The combinations of the vertical forces and the horizontal shear forces (especially those parallel with the frontal plane) generate additional forces which are have a twisting action on the foot, and in particular on transition zones of the foot, and also on a sole associated therewith.

For example, an identifiable transition zone is the articulation between the phalangeal area of the forefoot 2 and the metatarsal area of the mid-foot 3, which is suitable for transferring the articular movement from the depression phase to the phase relating to the second load peak and which is subjected to flexion and torsion forces.

Alternatively, another transition zone may be considered to be the articular portion between the area of the metatarsal and the tarsal. For a person skilled in the art, those anatomical references will be interpreted in an exemplary and non-limiting sense in respect of possible transition zones of the foot.

Advantageously, the sole 1 is affected in at least one of the zones of the forefoot 2 and/or mid-foot 3 by at least one recess 9.

In particular, the at least one recess 9 extends transversely relative to the toe/heel direction X.

Preferably, the at least one insert 10 is received in the at least one recess 9 so as to restore the continuity of the sole 1.

In particular, the at least one insert 10 is produced from a resilient polymer material, such as expanded polyurethane PU, or the like, having a hardness of approximately 40 Shore A, while the main portion 4 is produced from polymer material which is more rigid in relative terms than the portion of the insert 10 having a hardness of approximately 80 Shore A.

For the person skilled in the art, it is commonplace to identify in the field of the prior art which solution is most appropriate with regard to the material which is more rigid or more resilient in relative terms in the above-mentioned application field.

In this context, the term "received" is intended to indicate the action of receiving portions of materials in a manner adjacent, contiguous or corresponding to each other so as to maintain a continuity of the external profile of the sole.

Furthermore, that receiving action between the at least one insert 10 and the at least one recess 9 is brought about by way of fixing means which are typically used in the prior art being referred to, such as adhesive, stitches, nails and similar technical solutions which can readily be identified and adapted by the person skilled in the art.

Preferably, the at least one insert 10 and the at least one corresponding recess 9 extend so as to substantially affect the whole of the transverse extent of the tread surface 5, 6 of the sole 1 with a configuration tapered from the external side 8 up to the internal side 7 of the sole 1.

Preferably, the configuration of the insert 10 is tapered from the external side 8 up to (as far as) the internal side 7 of the sole.

In this context, the term "tapered" is intended to indicate a configuration or formation of the insert 10 or the recess 9 having a width Lt, transverse to a tapering direction R, which varies by decreasing in the sense in accordance with the tapering direction R itself.

With reference to Figure 1, the tapering sense and the direction R can preferably be identified as the sense and direction which extend from the external side 8 up to (as far as) the internal side 7 of the sole.

Preferably, the tapered configuration or formation of the insert 10 or the recess 9 provides for the transverse width Lt to vary by decreasing in the sense in accordance with the tapering direction R.

Preferably, the tapered configuration or formation of the insert 10 or the recess 9 provides for the transverse width Lt thereof to vary in the sense in accordance with the tapering direction R by decreasing in a progressive or monotonous manner. Alternatively, there could also be provided a discontinuous variation, that is to say, in which the insert 10 comprises portions which are adjacent in the tapering direction R and which have an identical transverse width Lt.

Furthermore, there could also be provided reduced intermediate portions between the two sides in which the transverse width Lt increases locally but without the insert generally losing the tapered progression.

Preferably, the transverse width Lt is parallel with the toe/heel direction X. There is provision for it to be possible to form in the sole 1 a plurality of recesses with corresponding inserts, though the solution which uses a single recess and a single corresponding insert 10 is preferable.

In a preferred embodiment, the vertex of the tapering is external with respect to the internal side 7 of the sole.

Advantageously, the insert 10 and the recess 9 have a trapezoidal outline, or completely trapezoidal outline, with a greater base 13 adjacent to the external side 8 and a smaller base 14 adjacent to the internal side 7 of the sole 1 and the convergence between the oblique sides 15, 16 is between 5° and 25°, preferably between 10° and 25°, and, in a further preferred manner, is approximately 15° (see Figures 1 and 3b).

In a preferred embodiment, the oblique side 15 which is closest to the forefoot zone 2 is substantially perpendicular to the toe/heel direction X while the opposite oblique side 16 is inclined with respect to this direction.

Furthermore, preferably, the insert 10 is arranged at the transition zone between the forefoot 2 and the mid-foot 3 which is defined at the metatarsal/phalangeal articulations of the foot.

In a preferred embodiment, the insert 10 and the recess 9 are between an edge of the tread surface of the forefoot zone 2 and an edge of the tread surface of the mid-foot zone 3.

In particular, the above-mentioned arrangement of the insert 10 is in correspondence with the transition zone of the metatarsal/phalangeal articulation between the forefoot 2 and mid-foot 3 and is such that it produces the optimum adaptability of the footwear to feet of different shapes.

In another preferred embodiment, the insert 10 is visible on the tread surfaces 5, 6.

In particular, if the insert is applied in a visible manner to a tread surface 5, 6 or to an arch-support (not shown in the Figures) so as to appear through the sole, it also produces a pleasant decorative effect which is in particular distinctive of the footwear.

Furthermore, the insert 10 may optionally be applied directly to the arch- support before the main portion 4 of the sole 1 is applied to the above-mentioned arch-support.

In particular, in this case the application of the at least one insert 10 to the tread 5, 6 and/or to the arch-support is also carried out by way of fixing means which are typically used in the prior art being referred to, such as adhesive, stitches, nails and similar technical solutions which can readily be identified and adapted by the person skilled in the art.

Alternatively, however, there is provision for the insert 10 to be at least partially sunk in the thickness of the sole, as described below.

In a preferred embodiment, the insert 10 comprises a base 11 and a bead 12 which is in relief from the base 11 and which is capable of increasing the directional control of the application axis of at least one force acting on the sole 1.

In particular, the at least one force acting on the sole 1 is a vertical force, a shear force and/or a combination thereof.

In fact, when the insert is at least partially visible on the tread surfaces 5, 6, it can advantageously be produced with a base 11 which is capable of being applied or fixed to the sole 1, and a bead 12 which is similar to a projection from the base 11, which appears through a corresponding through-opening 12a of the sole (see Figures 2a, 2b, 2c).

Preferably, the recess 9 comprises a base surface 11a for the base 11 of the insert 10 and a through-opening 12a for the bead 12 (see Figures 2b and 2c).

In a preferred embodiment, the base surface 11a is a planar surface which is parallel with the extent of the tread surfaces 5, 6 or which is inclined with respect thereto.

In particular, it is further preferable for the recess 9, in which there is formed the through-opening 12a for the bead 12, to comprise a step 12b between the through-opening 12a and the tread surfaces 5, 6.

A preferred embodiment of the recess 9 is illustrated in detail to an enlarged scale in Figure 2c, wherein there is present the base surface 11a which is received at the opposite side to the tread surfaces 5, 6, the through-opening 12a arranged almost at the centre of the recess 9 and extending almost over the entire extent of the recess 9 itself in a transverse direction to the direction X and a decline 12c between the tread surfaces 5, 6 and the through-opening 12a.

Preferably, the bead 12 is of semi-cylindrical form and is intended to be received in the through-opening 12a. The insert 10 is thereby partially sunk in the structure of the sole.

Advantageously, the insert 10, the main portion 4 of the sole, the bead 12, the step 12b and/or the decline 12c and other portions of the sole 1 are produced from polymer material by means of suitable processing techniques which are readily identifiable and modifiable by the person skilled in the art, such as injection- moulding, cast moulding, thermo-forming and the like.

In another alternative form of the invention illustrated in Figures 4a-c and 5a-c, the tread surface may have a plurality of through-openings 12a through which a portion of the insert 10 is evident.

Still with reference to those Figures, the tread surface preferably comprises a plurality of notches 17 which extend between the external side 8 and the internal side 7 of the sole.

In a preferred embodiment illustrated in Figures 4a-c, the notches 17 extend in a halo-like manner and follow a narrowed course in accordance with the course of the insert 10.

In this manner, the effects in terms of improving the flexural and torsional capacity of the sole conferred by the presence of the insert 10 can be maximized while providing a high level of protection of the tread surface.

In another embodiment illustrated in the Figures, the notches 17 extend substantially perpendicularly to the longitudinal direction of the sole.

This allows an increase in the flexibility in the articulation zone between the phalangeal area of the forefoot 2 and the metatarsal area of the mid-foot 3. According to a preferred embodiment, the sole may comprise a central weight reduction member 18 which defines a concavity in the tread surface in such a manner that it is in the form of a peripheral edge at the weight reduction member itself. The presence of the central weight reduction member 18 is found to be particularly advantageous by allowing the production of a more gradual support and by increasing the comfort during walking.

In an embodiment which is described in Figures 4c and 5c, the sole comprises additional weight reduction members 19 which are constructed at the intersection zone between the perimeter of the central weight reduction member 18 and the notches 17.

This allows an increase in the effect of the presence of the insert at the central weight reduction member 18, thereby allowing an optimum association of the provided features of flexibility and comfort associated with the weight reduction member 18 and the insert, respectively.

As a result of the features of the invention, the sole 1 for footwear is adapted to feet of different morphologies and is capable of optimizing comfort during walking.

Naturally, a person skilled in the art may apply to the above-described invention additional modifications and variants for the purpose of complying with specific and contingent application requirements, which variants and modifications are still included within the scope of protection as defined by the appended claims.

Claims

1. A sole (1) for footwear comprising a main portion (4) and at least one insert (10) of a material which has greater resilience than the main portion (4), the main portion (4) extending in a toe/heel direction (X) with identification of a respective forefoot zone (2) and mid-foot zone (3) which are contiguous in the toe/heel direction (X), the forefoot zone (2) and mid-foot zone (3) both having respective tread surfaces (5, 6) which are peripherally delimited by a respective internal and external side (7, 8) of the sole, the sole (1) being affected in at least one of the forefoot zone (2) and/or mid-foot zone (3) by at least one recess (9) which extends transversely relative to the toe/heel direction (X), the at least one insert (10) being at least partially received in the at least one recess (9),

characterized in that the insert (10) extends so as to affect substantially the whole of the transverse extent of the tread surface (5, 6) of the sole (1), and having a configuration tapered from the external side (8) up to affecting the internal side (7) of the sole (1).

2. A sole (1) for footwear according to claim 1, wherein a vertex of the tapered configuration is external with respect to the internal side (7) of the sole (1).

3. A sole (1) for footwear according to either of the preceding claims, wherein the insert (10) is received in the recess (9) so as to restore the continuity of the sole (1).

4. A sole (1) for footwear according to any one of claims 1 to 3, wherein the at least one recess (9) extends so as to substantially affect the whole of the transverse extent of the tread surface (5, 6) of the sole (1), and having a configuration tapered from the external side (8) towards the internal side (7) of the sole (1).

5. A sole (1) for footwear according to claim 4, wherein the insert (10) and the recess (9) have a substantially trapezoidal outline with a greater base (13) adjacent to the external side (8) and a smaller base (14) adjacent to the internal side (7) of the sole (1) and the convergence between the oblique sides (15, 16) is between 5° and 25°.

6. A sole (1) for footwear according to claim 5, wherein the convergence between the oblique sides (15, 16) is between 10° and 25°.

7. A sole (1) for footwear according to claim 6, wherein the convergence between the oblique sides (15, 16) is approximately 15°.

8. A sole (1) for footwear according to one or more of the preceding claims, wherein the insert (10) is visible on the tread surfaces (5, 6).

9. A sole (1) for footwear according to one or more of the preceding claims, wherein the insert (10) is at least partially sunk in the tread surface (5, 6).

10. A sole (1) for footwear according to one or more of the preceding claims, wherein the insert (10) comprises a base (11) and a bead (12) which is in relief from the base (11) and which is capable of increasing the directional control of the application axis of at least one force acting on the sole (1).

11. A sole (1) for footwear according to claim 7, wherein the recess (9) comprises a base surface (11a) for the base (11) of the insert (10) and a through-opening (12a) for the bead (12).

12. A sole (1) for footwear according to any one of the preceding claims, wherein the insert (10) and the recess (9) are between an edge of the tread surface of the forefoot zone (2) and an edge of the tread surface of the mid-foot zone (3).

13. A sole (1) for footwear according to any one of the preceding claims, wherein the insert (10) is produced from a material having greater resilience than the main portion (4).