WO2010084367A1

WO2010084367A1 - Footwear cuschioning sole and process for making same

Info

Publication number: WO2010084367A1
Application number: PCT/IB2009/000105
Authority: WO
Inventors: Marco Bramani
Original assignee: Vibram S.P.A.
Priority date: 2009-01-22
Filing date: 2009-01-22
Publication date: 2010-07-29

Abstract

A sole (1), and particularly, a rubber sole with holes (3), in which such holes pass through the thickness (2) of the sole (1) in a substantially transversal direction (T) to the sole (1), as well as a method for obtaining the sole (1) and the holes (3) by means of a compression-moulding process.

Description

"FOOTWEAR CUSCHIONING SOLE AND PROCESS FOR MAKING SAME"

Technical Field

The invention relates to a shock-absorbing sole for footwear and a process for realising the sole, and, more in detail, a rubber sole having a shock- absorbing effect featuring holes in the thickness thereof of various sizes, shapes and positions, possibly filled with another softer material, and a process for realising the holes in a rubber sole.

Background Art

For many years, in the sector of soles for footwear, new products and technologies have been under development, designed to increase the shock-absorbing capacity of the sole as well as the characteristics of comfort thereof, while also offering pleasing aesthetic qualities.

Some types of sole have been known for some time having devices incorporated in the thickness of the sole suitable for effectively absorbing shocks sustained by the foot in the impact thereof with the ground, as well as being adapted to colour the sole of the shoe originally or variously conformed such as to satisfy the aesthetic tastes of the consumer. In particular, soles are present on the market which internally feature shock-absorbing cushions made of various materials, colours and shapes and filled with fluids or gels of various natures. In this way an effective absorption of the traumas to which the foot is subject is obtained, and what is more the sole of the footwear is aesthetically attractive. From the point of view of the technological process, in order to obtain a sole made of a plastic material for footwear, traditional methods use the known procedure of injection under pressure, in which some special plastic materials - typically polyurethane polymers, thermo-plastic polymers, ethylene-vinyl acetate and the like - are injected into a specially- shaped mould and, thanks to the high pressure used for the injection, take on the shape of the mould once solidified. In the case of rubber soles - e.g. natural rubber, styrene rubber, butadiene rubber, etc. - the traditional manufacturing methods use compression moulding methods, in which a determined quantity of rubber is placed in a mould, which is closed with a certain pressure and contemporaneously heated in order to vulcanise the rubber. The present invention relates to a shock-absorbing sole, and the process for realising the sole, which is different to traditional soles, mainly thanks to the different type of material used for producing the sole .

Objects of the Invention

The technical aim of the present invention is to improve on the prior art in the sector of manufacturing soles for footwear.

Within the scope of such technical aim, one object of the present invention is to realise a sole featuring, in its thickness, holes that enable a reduction in the mechanical stress suffered throughout the foot and in particular in the rear part of the heel. A further object of the present invention is to realise a sole that is distinguished by a greater absorbing capacity of the forces of impact on the foot and the shocks to which it is subjected.

A further object of the present invention is to realise a sole which features holes suitable for offering new levels of comfort. A further object of the present invention is to realise a sole which features holes suitable for offering new perspectives in aesthetics and design. A further object of the present invention is to increase the flexibility of the sole in the rear part of the heel, or also over the entire sole. A further object of- the present invention is to provide an original style choice.

A further object of the present invention is to realise a sole which is suited to both sports footwear and casual footwear, and more generally which is suitable for all types of footwear.

A further object of the present invention is to enable an arrangement of holes in both the tread and the heel . A further object of the present invention is to be able to make holes in soles of various materials, among which rubber, plastic materials etc. A further object of the present invention consists in providing especially light soles of great thickness. A still further object of the present invention is to realise a compression-moulding process of soles for footwear which is simple and quick.

A further object of the present invention is to provide a process for realising a sole for footwear which features special aesthetic aspects and high levels of comfort.

A further object of the present invention is to realise a compression-moulding process which enables use of innovative materials that are also different from those normally used for footwear soles with holes. A further object of the present invention is to contemporaneously obtain moulding and vulcanising processes of the material the sole is made of. A further object of the present invention is to reduce the manufacturing costs of the sole.

This aim and these objects are attained by the present shock-absorbing sole for footwear, as specified in claim 1, and a process for realising the sole, as specified in claim 11. The dependent claims relate to preferred and advantageous embodiments of the invention. Brief description of the Drawings.

Further characteristics and advantages of the invention will better emerge from the detailed description that follows of a sole, illustrated by way of non-limiting example, in the accompanying figures of the drawings, in which: figure 1 is a lateral view of the sole of the present invention featuring holes in a thickness thereof; figure 2 is a lateral view of a further embodiment of the sole of the present invention, featuring holes in the thickness thereof; figure 3 is a perspective view of the lower mould for the compression-moulding process of the sole in accordance with the present invention; figure 4 is a further perspective view of the lower mould of figure 3, during the stage of filling the mould with a first portion of material to be moulded; figure 5 is a perspective view of the same lower mould, during the stage of insertion of the bars for the moulding process of the invention; figure 6 is a perspective view of the lower mould with the bars completely inserted therein; figure 7 is a perspective view of the lower mould during the covering stage of the bars with a second portion of material to be moulded; figure 8 is a perspective view illustrating the stage of extraction of the bars from the lower mould; figure 9 is a perspective view from above illustrating a detail of the extraction stage of the bars from the lower mould, and the finished sole which is ready to be extracted from the lower mould.

Embodiments of the Invention With reference to figures from 1 to 9, reference number 1 denotes a shock-absorbing sole of the present invention.

The sole 1 features, in its thickness 2, one or more through-holes 3 passing through the thickness 2, in a substantially transversal direction T with respect to the sole 1. The holes 3 can be present in the rear zone 4 of the sole 1, in a front zone or a central zone, or can be distributed along the whole longitudinal axis L of the sole 1.

The holes 3 can be aligned along a same plane, as in figure 1, or can follow the profile shape of the sole 1, as in figure 2.

In the present invention, the sole 1 is made of a substantially elastically yielding material which is particularly similar to natural or synthetic rubber, or mixtures of rubber and its derivatives. In detail, it can be of a natural rubber, a synthetic rubber, a styrole rubber, a styrene-butadiene rubber, a poly- butadiene rubber, a nitryl rubber, a butylic rubber, a foam rubber and various mixtures of rubber or similar materials.

The holes 3 can advantageously be made in both the tread 5 of the sole 1 and in the heel, which can be made of polyurethane, ethyl-vinyl-acetate, etc. It is further specified that it is possible to realise the holes 3 in soles made of various materials, among which rubber, plastic materials, polymers and so on.

The holes 3 can be advantageously filled with a further component, made of rubber or another material, having the same characteristics of the material that the sole 1 is made of, or featuring other characteristics, e.g. the filling material can be more yielding than the surrounding material. Naturally the holes 3 can have any transversal section, e.g. round, oval, square or another shape.

The holes 3 can internally have the same colouring as the surrounding sole 1, or can have different colours . The holes 3 can be made in the soles of various types of footwear, either sporting or casual and more generally all types of footwear.

The production process for obtaining the sole 1, which the present invention relates to, is in particular a compression-moulding process, developed in relation to the type of material the sole 1 is composed of.

It is specified that the process, illustrated in figures 3 to 9, is performed at a temperature comprised between 140-190⁰C, and preferably at a temperature of between 160° and 180°. The temperature can vary according to the material used, the composition thereof and the size of the object to be produced. The process for realising the sole 1 of the present invention actuates the stages as set down herein below.

In a first stage of the process (figure 3) a lower mould is prepared, denoted by 10 in the figures, which follows the geometry of the lower portion of the sole 1 to be made, and thus defines a sort of moulding chamber. The lower mould 10 has lateral openings 10a which correspond, both in the dimensions thereof, and in the positioning thereof, to the holes 3 which must be realised in the sole 1. For the first stage, one or more bars are also used, denoted by 11, intended to realise the holes 3 in the thickness 2 of the sole 1. The bars 11 are preferably made of metal, or in another material suitable for the purpose, and have respective external diameters which are equal to those of the holes 3 to be obtained in the sole 1.

In a next stage of the process of the invention (figure 4) a first portion, denoted by number 12, of the rubber material to be used for realising the sole 1 is deposited internally of the lower mould 10. The first portion 12 is preferably shaped as a substantially rectangular sheet, or another shape, having dimensions and thickness which are chosen according to the sole to be realised. In a further stage of the process (figure 5) the bars 11 are inserted internally of the lower mould 10, via the lateral openings 10a, in a substantially transversal direction T with respect to the sole 1 and across the whole width of the sole 1 (as illustrated in figure 6) . A stage of the process (figure 7) then follows in which a second portion 13 of the rubber material for realising the sole 1 is deposited internally of the lower mould (10) , which second portion 13 is also made of a sheet of a substantially rectangular shape or another specially selected shape; the second portion 13 wholly or partially covers the bars 11 positioned internally of the lower mould 10 and passing through the thickness 2 of the sole 1. In a further stage of the process, the lower mould 10 is closed with an upper mould (not illustrated in the figures) which corresponds to the lower portion of the sole 1 (i.e. the tread 5), and the compression- moulding process begins, at high temperature, between 140-190⁰C, and preferably between 160° and 180°, for a variable time from 1 to 30 minutes and sufficient, on the basis of the material used, for obtaining the sole 1.

During this time the rubber expands internally of the mould by compression and heating, and takes on the desired shape of the sole 1, featuring the holes 3 which form thanks to the presence of the bars 11. The rubber-heating modes can vary in relation to the type of plant used: in more detail, the moulds can be heated before or after the positioning of the material and by means of jets of hot steam, hot water, electric resistance elements or any other heating devices, generally used for this purpose. In the final stage of the process (after the vulcanisation or reticulation of the material) the lower mould 10 and the upper mould are distanced from one another, such as to open the moulding chamber (figure 8), and the bars 11 that have formed the holes 3 are extracted laterally (figure 9) . At the end of the process the sole 1 is thus completely formed.

In a following stage of the process, the rubber material is cooled. The cooling process can be done following the methods in general use. As mentioned above, the material used for realising the sole can be rubber or another material suited to the production of a sole with holes obtained by means of the above-described process.

Thus the invention fully attains the set objects. The sole of the present invention, made of a rubber- type material and provided with the above-described holes, enables impact stresses on the foot to be considerably reduced, thanks to the elastic properties of the material and the special conformation of the sole. In this way the user's comfort when using the footwear is considerably improved, as well as the flexibility of the sole and the lightness thereof.

A further advantage obtained with the present invention consists in the capacity to keep these elastic properties over a longer period of time, reducing the ageing of the sole and thus the shoe itself .

The sole of the invention is distinguished by particularly pleasing and innovative aesthetic characteristics, obtained with decidedly lower production costs with respect to traditional technologies .

The present invention thus conceived is susceptible to numerous modifications and variants, all falling within the scope of protection of the claims.

Claims

1) Shock-absorbing sole for footwear, made of an elastically-yielding material of a rubber-type, characterised by the fact that it comprises at least a hole (3) passing through a thickness thereof (2), in a substantially transversal direction (T) .

2) Sole as claimed in claim 1, characterised by the fact that it is made of natural rubber.

3) Sole as claimed in claim 1, characterised by the fact that it is made of synthetic rubber.

4) Sole as claimed in claim 1, characterised by the fact that it is made of a mixture of natural rubbers and/or synthetic rubbers .

5) Sole as claimed in any one of the previous claims, comprising a plurality of holes (3) passing through said thickness (2) and distributed in a rear zone (4) thereof.

6) Sole as claimed in any one of the previous claims, comprising a plurality of holes (3) passing through said thickness (2) and distributed substantially along a whole length of the sole.

7) Sole as claimed in any one of the previous claims, characterised by the fact that at least one of said holes (3) is filled with the same material the sole is made of. 8) Sole as claimed in any one of the previous claims, characterised by the fact that at least one of said holes (3) is filled with a further soft and elastically-yielding material. 9) Sole as claimed in any one of the previous claims, characterised by the fact that said further soft and elastically-yielding material is chosen from among foam rubber, EVA, polyurethane and the like.

10) Sole as claimed in one or more of the previous claims, characterised by the fact that at least one of said holes (3) is realised through a tread (5) thereof.

11) Sole as claimed in one or more of the previous claims, characterised by the fact that at least one of said holes (3) is realised through a heel thereof.

12) Process for realising a shock-absorbing sole (1) for footwear, comprising the following stages: preparing at least a lower mould (10) which follows the geometry of said sole (1), which lower mould (10) is provided with at least a lateral opening (10a) ; depositing, internally of said lower mould (10), a portion (12) of rubber-type material; inserting internally of said lower mould (10) at least a bar (11) through said at least an opening (10a) , said at least a bar (11) being adapted to realise, in the thickness (2) of said sole (1) , at least a respective through-hole (3) , arranged in a substantially transversal direction (T) ; closing at least an upper mould onto said lower mould (10) ; heating said lower mould (10) and said upper mould to a predetermined temperature; distancing said upper mould from said lower mould (10); extracting said bars (11) from said openings (10a); extracting said sole (1) from said lower mould (10); cooling said sole (1) .

13) Process as claimed in claim 12, comprising a stage of depositing a further portion (13) of rubber- type material internally of said lower mould (10a) , substantially above said bars (11) . 14) Process as claimed in claim 12 or 13, characterised by the fact that said stage of heating said lower mould (10) and said upper mould is done to a temperature comprised between 140° and 190⁰C. 15) Process as claimed in any one of claims from 12 to 14, characterised by the fact that said bars (11) are made of a metal material.

16) Process as claimed in any one of claims from 12 to 15, characterised by the fact that said portion (12) of rubber-type material is realised in a sheet of a shape, dimensions and thickness which are chosen depending on the sole (1) to be realised.

17) Process as claimed in any one of claims from 12 to 16, characterised by the fact that said further portion (13) of rubber-type material is realised in a sheet of a shape, dimensions and thickness which are chosen depending on the sole (1) to be realised.