WO2013131855A1

WO2013131855A1 - An improved shoe sole

Info

Publication number: WO2013131855A1
Application number: PCT/EP2013/054290
Authority: WO
Inventors: Alberto RECCHIONI
Original assignee: Recchioni Alberto
Priority date: 2012-03-06
Filing date: 2013-03-04
Publication date: 2013-09-12
Also published as: ITAN20130018U1; EP2822416A1

Abstract

A shoe sole (1) comprises at least one walking surface intended to come in contact with the ground during walking, said sole (1) comprising a plurality of notches (2,3) able to improve grip on slippery ground.

Description

An improved shoe sole

The present invention relates to an improved shoe sole characterized by high anti-slip properties, especially on wet, muddy, snowed and iced surfaces.

The term "sole" herein indicates the part of the shoe intended to come in contact with the ground during walking; instead, the term "shoe" refers to all kinds of shoes, boots, and the like, for men, women and children.

Today's shoe soles are always unsuitable for slippery ground, although they are made of anti-slip material, such as rubber or the like, and suitably provided with a series of deep large grooves.

When a water layer is interposed between two solid surfaces, such as sole and ground, the contact surface between the two solid surfaces is reduced, with consequent reduction of the coefficient of friction, thus generating unstable balance that makes the sole slip.

Such a situation also occurs when snow, water, mud or the like is found on the ground.

The purpose of the present invention is to overcome such disadvantages by providing a shoe sole characterized by an excellent coefficient of friction, technically defined as "grip", also on slippery ground, such as iced, snowed, wet ground or the like.

These purposes are achieved with the sole according to the first attached claim, the primary peculiarity of which is the provision of thin deep notches.

Additional advantages come from the dependent claims, which comprise optional characteristics of the sole of the present invention.

For explanatory reasons, the description of the sole according to present invention continues with reference to the attached drawings, which only have illustrative, not limiting value, wherein: - Fig. 1 is a view of the walking surface of a sole according to the present invention;

- Figs. 2-4 are views of morphological variants of said notches provided in the sole of Fig. 1 ;

- Figs. 5-7 are views of additional morphological variants of said notches provided in the sole of Fig. 1 ;

- Figs. 8-1 1 are views of additional morphological variants of said notches provided in the sole of the invention.

Fig. 1 is a view of the walking surface of a sole (1 ) according to the present invention;

The walking surface of the sole (1 ) is provided with a plurality of thin deep notches (2), the dimensions of which are precisely indicated hereinafter.

According to the precepts of the invention, the notches (2) extend along a direction preferably transversal to the sole, e.g. along a trajectory intersecting the longitudinal axis (Y-Y) of the sole (1 ) with 90° angle, with range of approximately 30°.

In any case, it must be immediately noted that said notches (2) can have any direction, without significantly impairing the final results in terms of coefficient of friction of the sole (1 ), given the fact that said coefficient mostly depends on the width and depth of said notches (2).

Said coefficient is not affected by the fact that the walking surface of the sole (1 ) is provided with a network of deep large grooves (1 a) intended to define relief pieces (3), as shown in Fig. 1 .

However, it is evident that in such a case said notches (2) must be provided on the walking surface of said pieces (3), as shown in Fig. 1 .

Still according to the invention, the walking surface of the sole (1 ) is provided with multiple rows of notches (2), said rows preferably having parallel or similar trajectories. It must be noted that said trajectories can indifferently have any type of profile, such as a rectilinear, curvilinear, undulated, or toothed profile, including the profile of a more or less regular broken line. In any case it is only important that the notches (2) have width and depth of the value specified here below.

In some of the attached figures, the width of the notch (2) is indicated with letter (s), which is hereinafter used with reference to this physical quantity of the notch (2).

Numerous experimental tests both in vivo and laboratory confirmed that the high coefficient of friction of the sole of the invention was exclusively obtained through a careful selection of the width and depth dimensions of each notch (2), having

♦ width (s) comprised between 0.2 mm and 1 .0 mm

♦ depth comprised between 2.0 mm and 1 0 mm

The best results were obtained within the following range of values:

♦ width (s) of notch: from 0.3 mm to 0.7 mm

♦ depth of notch: from 3.0 mm to 6.0 mm.

The measurements made by certification laboratories detected the following values of the coefficient of friction.

TEST ONE:

- made according to EN ISO 20344 :2004/A1 :2007; UNI EN ISO 13287:2008 Mod

- test ground: iced surface

- sole position : flat

- coefficient of friction: 0.36

TEST TWO:

- made according to EN ISO 20344 :2004/A1 :2007; UNI EN ISO 13287:2008 Mod

- test ground: ceramic surface + lubricant (water and detergent)

- sole position : flat

- coefficient of friction: 0.34

With reference to Fig. 4, said notches are provided with rectilinear section and zigzag section.

When the notch (2) is provided with zigzag profile and is repeated on multiple parallel rows, as shown in Figs. 1 -4, the tests confirmed that the best results are obtained when complying with the following dimensions, shown in Fig. 5:

♦ pitch (a) : comprised between 2.0 mm and 14 mm, with optimum range between 3.0 mm and 6.0 mm.

♦ distance (b) between two opposite crests: comprised between 1 .0 mm and 7.0 mm, with optimum range between 2.0 mm and 4.0 mm.

In some cases the transversal notches (2) have sharp corners, such as in Fig. 5, whereas in other cases they have rounded corners, such as in Fig. 6.

In the case of multiple parallel rows of notches (2), as shown in Figs. 1 to 4, the distance (d) between the rows must be comprised between 2.0 mm and 1 0 mm. The best results were obtained with a distance (d) comprised between 3.0 mm and 6.0 mm.

A special case is illustrated in Fig. 7, wherein two rows of zigzag notches (2) intersect, generating a substantially diamond pattern.

Figs. 8-1 1 show not only parallel rows of notches (2), but real networks of notches (2) forming meshes with the most diverse shape; the latter configurations must respect the aforementioned dimensional conditions in terms of width (s) and depth of each notch (2).

With reference to the preferred material, the Applicant noted that the best results are obtained with abrasion-resistant materials with low density and low specific weight.

Advantageous materials for the realization of the sole (1 ) are for instance: rubber, polyurethane (PU) in various combinations of polyoils and isocianates, rubber and polyurethane in different layers, polyurethane compounds (mixtures of polyurethane resins with isocianates), TPE (thermoplastic isocianate elastomers). All these materials are well known to the operators of the field and in particular to the manufacturers of shoe bottoms obtained with injection molding, casting or vulcanization, EVA.

In any case, the best results were obtained using rubber with hardness comprised between 50 or 60 shore, or polyurethane with specific weight lower than 0.7 g/cm³. Said notches (2) work as follows: transversal notches (2) with the aforementioned dimensions break the thin water layer that is generated on wet ground and convey water between said notches, pushing it towards the sides of the sole (1 ) because of the weight of the user, generating a sort of "pump-effect".

In view of the above, friction between the sole (1 ) and ground increases, thus causing a higher grip.

The same occurs on iced ground because the ice surface in contact with air contains a semi-liquid layer that acts as lubricant.

In case of snowed surface, it was noted that, when the foot is laid onto the ground, the notches trap fresh snow and compact it because of the pressure exerted by the weight of the body.

After the first impact with the snow, a snow/snow contact is established and this creates a higher friction than the snow/rubber friction obtained with an ordinary sole.

This creates a "claw effect" due to the action of the snowflakes that remain compact and are trapped inside the notches, acting as thousands of minute claws gripping the ground.

In general the presence of said notches (2) increases the elasticity of the sole (1 ), thus allowing for a better grip at any ground temperature.

Claims

1 . A shoe sole (1 ) characterized in that the walking surface of said sole (1 ) is provided with notches (2) having:

- width (s) comprised between 0.2 mm and 1 .0 mm

- depth comprised between 2.0 mm and 10 mm

2. The sole (1 ) of the preceding claim, characterized in that said notches (2) are disposed in multiple rows, between which a distance (d) from 2.0 mm to 10 mm is provided.

3. The sole (1 ) of the preceding claim, characterized in that at least one notch (2a) for connection between rows is provided between said rows of notches (2).

4. The sole (1 ) of one of the preceding claims, characterized in that said notch (2) has a zigzag profile, where:

- pitch (a) is comprised between 2.0 mm and 14 mm,

- distance (b) between two opposite crests is comprised between 1 .0 mm and 7.0 mm.

5. The sole (1 ) of one of the preceding claims, characterized in that said notches (2) extend along a direction preferably transversal to the sole, e.g. according to a trajectory intersecting the longitudinal axis (Y-Y) of the sole (1 ) with 90° angle, with range of approximately 30 °.

6. The sole (1 ) of one or more of the preceding claims, characterized in that the sole is made of rubber with hardness comprised between 50 and 60 shore.

7. The sole (1 ) of one of the preceding claims 1 to 5, characterized in that it is made of polyurethane with specific weight lower than 0.7 g/cm³.