Patent Description:
As is known, currently the insoles or footbeds of trainers or sneakers are increasingly technical and provide different characteristics to the shoe and the user.

In general, in order to try to obtain comfort, softness, polyurethane foam is known to be used for the insoles, which however is subjected to continuous and cyclic stresses of the walk and tends to collapse on itself or to flatten.

In an attempt to provide structural stiffness, inserting inserts of stiff material in given positions of the insole is also known.

These inserts provide stiffness to the insole, but can result in a loss of comfort since they are perceived by the user as a discontinuity of stiffness under the foot.

In order to try to solve the above-mentioned problems, a method has been proposed for making an insole and/or footbed made of two polyurethane materials, described in the utility model <CIT> in the name of the same Applicant.

However, the Applicant has observed that the implementation of what was described in the utility model application <CIT> is complex and not efficient in terms of hourly production and, consequently, production costs.

The Applicant has in fact observed that the making of the insole described in <CIT> occurred with a double casting technique in a single mould. In other words, inside the same mould, the two components constituting the insole, which were coupled to each other, were made. Between the first casting and the second casting, the lid or male mould was replaced.

According to this method, before the mould can be opened at the end of the first casting operation, a certain period of time must elapse in order to allow the material to stabilise. In other words, assuming a time T for the first casting operation, e.g., <NUM> minutes, at the end of the first casting step, a time of at least T/<NUM> must elapse, i.e. a time greater than <NUM> minutes to stabilise the material.

However, since a time T with the mould closed is also necessary to stabilise the material at the end of the second casting, the overall time for extracting the insole from the mould could not be less than at least T+T/<NUM>, i.e. for example <NUM> minutes, a time therefore too long to produce a single piece.

Such a high time of unit production makes the process uncompetitive.

The Applicant has also observed that attempting to reduce the mould opening time in the first or second casting step resulted in a very high quantity of waste.

The Applicant has also noticed that with the method described in the utility model application <CIT>, if the first casting product (first casting) was affected by casting burrs or other moulding defects, these could not be removed. The product of the first casting which was not yet stabilised could not, in fact, be removed from the mould. Therefore, on the same mould the second casting was made, which incorporated the burrs and possible further moulding defects, thus resulting in unaesthetic defects of the finished product.

The Applicant has therefore found the need to make a new process for making an insole and/or footbed composed of at least two coupled components made of polyurethane and/or thermoplastic polyurethane materials having different density, which does not have the drawbacks of the known art. <CIT> discloses a process for making an insole composed of at least two components in a mould.

Therefore, the present invention concerns a process for making an insole and/or footbed according to appended claim <NUM>.

The present invention, in the aforesaid aspect, may have at least one of the preferred features described below.

Preferably, the first polyurethane material adapted to make said first supporting element has a Shore A hardness of between <NUM> and <NUM>.

Advantageously, the first polyurethane material adapted to make the first supporting element comprises isocyanate and polyol.

Conveniently, the first polyurethane and/or thermoplastic polyurethane material adapted to make said first supporting element comprises an amount of isocyanate of between <NUM> and <NUM> parts by weight with respect to <NUM> parts by weight of polyol.

Preferably, the second polyurethane and/or thermoplastic polyurethane material adapted to make the second supporting element has a Shore A hardness of between <NUM> and <NUM>.

Advantageously, the second polyurethane and/or thermoplastic polyurethane material adapted to make the second supporting element comprises isocyanate and polyol, said isocyanate having an amount of between <NUM> and <NUM> parts by weight with respect to <NUM> parts by weight of polyol.

Conveniently, the step of allowing the second foamable polyurethane and/or thermoplastic polyurethane material to foam to make said second supporting element is implemented so that the negative shape of said second supporting element is defined, at least partially, by the coupling between the first supporting element and second upper lid of said second mould.

Preferably, the step of casting in a first mould a first foamable polyurethane and/or thermoplastic polyurethane material is carried out on a first rotary table machine comprising a plurality of first moulds arranged circumferentially and rotatable along a circumferential path.

Advantageously, the process comprises a step of inserting at least one insert into a seat in said first supporting element before inserting said first supporting element into a second mould.

Further characteristics and advantages of the invention will become more apparent from the detailed description of some preferred but not exclusive embodiments of a process for making an insole and/or footbed for shoes.

Such description will be set forth hereinafter with reference to the appended drawings provided for indicative, and therefore non-limiting, purpose only, wherein:.

With reference to the figures, an insole and/or footbed for shoes made by the process according to the present invention is depicted by the reference numeral <NUM>.

In particular, the insole and/or footbed <NUM> is made of at least two foamable polyurethane and/or thermoplastic polyurethane materials of different stiffness.

As can be seen in <FIG>, the insole has a first supporting element <NUM> directed toward the ground and to provide structural stiffness to the insole and/or footbed <NUM>. The first supporting element <NUM> is configured so as to accommodate, in a hull-shaped portion <NUM> thereof, a second supporting element <NUM> configured to contact the user's foot.

In the <FIG>, the first <NUM> and the second <NUM> supporting elements extend in a longitudinal direction for the whole foot of the user and, consequently, for the whole shoe. Alternatively, the first <NUM> and the second <NUM> supporting elements could extend for a smaller dimension, e.g., for <NUM>% or <NUM>% of the total longitudinal extension of the user's shoe or foot, without departing from the protection scope of the present invention, as defined by the claims.

Longitudinal direction means the direction of extension of the shoe, which can be identified by a straight line substantially at the centre-line of the sole, passing between the portion intended to accommodate the heel and the portion intended to accommodate the toes.

Again with reference to <FIG>, the first <NUM> and the second <NUM> supporting elements have substantially the same shape in plan view, apart from a slight perimeter offset toward the outside, of the order of a few mm, of the first supporting element <NUM>.

The first supporting element <NUM> is made of polyurethane foam with a Shore A hardness of between <NUM> and <NUM>, more preferably a Shore A hardness of between <NUM> and <NUM>.

The first supporting element <NUM> does not have constant thickness along its extension but a variable thickness, preferably a thickness which varies between <NUM> and <NUM>.

The thickness of the first supporting element <NUM> varies according to the anatomicity to be provided to the same first element.

The first supporting element <NUM> has a hollow portion or a cavity <NUM> such as to completely house the second supporting element <NUM>.

In particular, the first supporting element is arranged so as to form a cavity or a hull adapted to completely house the first supporting element <NUM>.

The cavity in <FIG> is obtained by an upward folding of the outer perimeter edge <NUM>' of the first supporting element <NUM>.

The first supporting element <NUM> has a thickness which varies along its extension both in the longitudinal and transverse directions.

Transverse direction means a direction substantially orthogonal to the longitudinal direction.

In <FIG>, the first element <NUM> has a minimum thickness at its perimeter edge <NUM>'.

Preferably, the first supporting element <NUM> is made of a polyurethane foam or thermoplastic polyurethane (tpu) foam comprising isocyanate, polyol and additives.

The first supporting element <NUM> is made of a polyurethane foam and/or thermoplastic polyurethane foam comprising an amount of isocyanate of between <NUM> and <NUM> parts by weight with respect to <NUM> parts by weight of polyol.

At the end of the production process of the insole <NUM>, described in greater detail below, the second supporting element <NUM> is coupled and enclosed at least on its side surfaces <NUM>' and on those <NUM>" facing downwards from the first supporting element <NUM>.

The second element <NUM> is also made of polyurethane foam or thermoplastic polyurethane (tpu) foam with a Shore A hardness lower than that of the first element <NUM>, preferably a Shore A hardness lower than <NUM>% with respect to the hardness of the material making the first supporting element <NUM>.

Preferably, the second element <NUM> has a Shore A hardness of between <NUM> and <NUM>, more preferably a Shore A hardness of between <NUM> and <NUM>.

Preferably, the second supporting element <NUM> is made of a polyurethane foam and/or thermoplastic polyurethane foam comprising isocyanate, polyol and additives.

The second supporting element <NUM> is made of a polyurethane foam and/or thermoplastic polyurethane foam comprising isocyanate, preferably an amount of isocyanate of between <NUM> and <NUM> parts by weight with respect to <NUM> parts by weight of polyol.

Preferably, the second supporting element <NUM> has a thickness which varies along its extension both in the longitudinal and transverse directions.

In <FIG>, the second supporting element <NUM> has a decreasing thickness away from the portion configured to be placed under the heel of the user to the front portion intended to be positioned, when the insole is inserted in the shoe, under the toes.

The thickness of the second supporting element <NUM> has a non-continuous decrease away from the portion which, when the shoe is assembled, is at the heel.

<FIG> and <FIG> show a variant of an insole made by the process according to the present invention, described in greater detail below. In particular, in this case, the insole <NUM> is made of at least four components of different stiffness and coupled together.

In <FIG> and <FIG>, the first and second supporting elements <NUM> and <NUM> are made of the same materials as those shown in <FIG> and for this reason not further described.

Again with reference to <FIG>, <FIG>, the first supporting element <NUM> has, at the heel region, a seat <NUM> adapted to receive a first insert <NUM> of jelly-like material which represents the third component of the insole <NUM>.

The insert <NUM> has a substantially circumferential shape with a radius of between <NUM> and <NUM>.

The first supporting element <NUM> also has a second peripheral seat <NUM>, of which <FIG> shows an upper edge, configured to house a fourth component referred to as second insert <NUM>, in the present description, which is also preferably of polyurethane or thermoplastic polyurethane material.

The second seat <NUM> and, consequently, the second insert <NUM> extend peripherally to the first supporting element <NUM> so as to wrap the first insert <NUM>. The second seat <NUM> and, consequently, the second insert <NUM> (fourth component) extend peripherally to the first supporting element <NUM> according to a path adapted to substantially form a "U" around the first insert <NUM> with the two tails of the "U" of different extension.

In particular, the tail of the "U" which, when the insole is assembled, is found on the transversely outermost side of the insole <NUM>, has a greater extension until it reaches substantially the forefoot.

Between the first insert <NUM> and the second insert <NUM> there are no contact points. In other words, a portion of the first supporting element <NUM> is arranged between the first insert <NUM> and the second insert <NUM>.

The second insert <NUM> has a series of adjacent ribs <NUM>, preferably four ribs <NUM>, which extend for the entire extension of the second insert <NUM>. In the figures the four ribs <NUM> also have a "U" arrangement.

The four ribs <NUM> have a height in the range between <NUM> and <NUM>.

The vertically outermost surfaces in the direction of the outside of the shoe of the insole <NUM>, i.e. of the first supporting element <NUM>, of the first insert <NUM> and the second insert <NUM> (the top of the ribs <NUM>) are substantially coplanar.

In <FIG>, <FIG>, the cavity of the hull-shaped portion <NUM> intended to accommodate, at least partially, the second supporting element <NUM> is located on the opposite side with respect to the seat <NUM>.

In other words, while the seat <NUM> is facing and overlooking the outside of the insole, i.e. the ground, a cavity of the hull portion <NUM>, not shown in <FIG>, <FIG>, will be facing the inside of the shoe, i.e. the user's foot.

Further elements or parts of the first supporting element <NUM>, made of inserts of different density, can be provided; by way of example, the crescent-shaped portion <NUM> in <FIG>, which should abut with an insole or footbed worn under the plantar arch, could be made of an insert of polyurethane foam or thermoplastic polyurethane foam material having hardness different, preferably lower, than that of the remaining part of the first supporting element <NUM>.

In a further aspect, the invention relates to a process for making an insole and/or footbed <NUM> composed of at least two components of polyurethane foam or thermoplastic polyurethane foam material, which have different density.

In the case of making the insole of <FIG>, the process begins by casting into a first mould <NUM> a first foamable polyurethane and/or a foamable thermoplastic polyurethane material to make a first supporting element <NUM> comprising at least one hull-shaped portion <NUM> comprising a cavity.

The first polyurethane and/or thermoplastic polyurethane material has a composition comprising isocyanate, polyol and additives.

The first polyurethane and/or thermoplastic polyurethane material adapted to make the second supporting element <NUM> has a Shore A hardness of between <NUM> and <NUM>, more preferably a Shore A hardness of between <NUM> and <NUM>.

The first mould <NUM> is then closed with an upper lid <NUM>' which reproduces in negative the dimensional characteristics to be provided to the upper surface of the first supporting element <NUM>.

When the first mould <NUM> is closed, the first polyurethane material is allowed to foam at room temperature for a given time, so as to form the first supporting element <NUM> of the insole and/or footbed <NUM>.

Subsequently, the first mould <NUM> is opened, i.e. after at least a stabilisation time of at least <NUM> seconds.

Therefore, once the first supporting element <NUM> formed has been extracted, a visual qualitative analysis of the same is carried out, aimed at identifying possible moulding defects and/or burrs.

In case moulding defects or burrs are present, they are removed, if possible, through traditional techniques, which are not further described.

If it is not possible to eliminate moulding defects or burrs, the defective first supporting element <NUM> is discarded.

At this point, in the case of the insole and/or footbed <NUM> shown in <FIG>, it is possible to store the first supporting element <NUM> or to directly make the second component or second supporting element <NUM> so as to complete the making of the insole and/or footbed <NUM>.

The first supporting element <NUM> is made on a first rotary table machine <NUM> comprising a plurality of first moulds <NUM> circumferentially and rotatably arranged along a circumferential path.

In order to complete the making of the insole and/or footbed <NUM> shown in <FIG>, the first supporting element <NUM> is inserted in a second mould <NUM>.

As shown in <FIG>, the second mould <NUM> is provided on a second rotary table machine <NUM> comprising a plurality of second moulds <NUM> circumferentially and rotatably arranged along a circumferential path.

Alternatively, the second mould <NUM> could also be provided on the same first rotary table machine <NUM> by replacing the first mould <NUM> with the second mould <NUM>.

The first supporting element <NUM> is positioned in the second mould <NUM> so as to have the cavity of the hull-shaped portion <NUM> thereof so as to accommodate the second polyurethane material.

In other words, the negative shape of the second supporting element <NUM> is defined, at least partially, by the coupling between the first supporting element <NUM> and the second upper lid <NUM>' of the second mould <NUM>.

A second foamable polyurethane and/or thermoplastic polyurethane material with a Shore A hardness of at least <NUM>% lower than the hardness of the first material making the first supporting element is then cast into the second mould <NUM> so that the hull-shaped portion <NUM> of the first supporting element <NUM> at least partially accommodates the second foamable polyurethane and/or thermal polyurethane material.

The second polyurethane material will be cast into the second mould to make the second supporting element <NUM> coupled to the first supporting element <NUM> and, simultaneously, the finished insole and/or footbed <NUM>, unless burrs and defects are to be removed.

The second polyurethane foam and/or thermoplastic polyurethane foam material adapted to make the second supporting element <NUM> has a Shore A hardness of between <NUM> and <NUM>, more preferably a Shore A hardness of between <NUM> and <NUM>.

The second mould <NUM> is then closed with an upper lid <NUM>' which reproduces in negative the dimensional characteristics to be provided to the upper surface of the second supporting element <NUM>.

Once the second mould <NUM> is closed, the second polyurethane material is allowed to foam at room temperature for a given time, so as to form the second supporting element <NUM> of the insole and/or footbed <NUM>.

The second supporting element <NUM> is therefore made as already coupled to the first supporting element <NUM>.

Subsequently, the second mould <NUM> is opened. The second mould <NUM> is preferably opened after a given stabilisation time, which can also be in this case estimated at about <NUM> seconds.

The insole and/or footbed <NUM> formed by the first <NUM> and the second <NUM> supporting elements coupled together, is then extracted.

During this step of casting the second polyurethane material, a sub-step of coupling to a covering layer, preferably of leather, can also be provided.

The covering layer may extend entirely across the second supporting element <NUM> and reproduce, in plan view, the shape of the second supporting element <NUM>.

The covering layer may have a thickness greater than <NUM>.

The covering layer is positioned above the second supporting element <NUM> so as to contact the foot wearing the insole or footbed.

Therefore, once the insole <NUM> formed has been extracted, a visual qualitative analysis of the same is carried out, aimed at identifying possible moulding defects and/or burrs.

If it is not possible to eliminate moulding defects or burrs, the insole and/or footbed <NUM> is discarded.

The process for making the insole shown in <FIG>, <FIG> is entirely similar to the one just described except that after the casting step of the first supporting element <NUM>, the first and second inserts, respectively <NUM> and <NUM>, are inserted therein and in particular in its seats <NUM> and <NUM>.

Once this operation is carried out, the first supporting element <NUM> can then be inserted into a second mould <NUM> to allow the second casting adapted to make the second supporting element <NUM> combined with the first supporting element <NUM>.

The advantages of the process for making an insole and/or footbed <NUM> composed of at least two components of foamable polyurethane materials according to the present invention, are numerous. In particular, we remember the possibility of eliminating some moulding defects of the first supporting element at the end of the first moulding step.

Moreover, the process, according to the present invention, allows to reduce the overall unit moulding time of the insole and/or footbed <NUM> as well as to produce and store the first supporting elements <NUM> in order to speed up the production of the batches in cases of peaks in demand.

Claim 1:
Process for making an insole and/or footbed (<NUM>) composed of at least two components of foamable polyurethane and/or thermoplastic polyurethane materials having different density, comprising the steps of:
- casting in a first mould (<NUM>) a first foamable polyurethane and/or thermoplastic polyurethane material with a Shore A hardness greater than <NUM> to make a first supporting element comprising at least one hull-shaped portion extending for at least <NUM>% of the first supporting element (<NUM>) at a rear portion of said first supporting element (<NUM>); said hull-shaped portion (<NUM>) comprising a cavity defined at least partially by perimeter edges having a height greater than <NUM>;
- closing the first mould (<NUM>) with a lid (<NUM>');
- opening said first mould (<NUM>) after at least one stabilisation time of at least <NUM> seconds;
- extracting the first supporting element (<NUM>) from said first mould (<NUM>);
- inserting the first supporting element (<NUM>) into a second mould (<NUM>);
- casting in said second mould (<NUM>) a second foamable polyurethane and/or thermoplastic polyurethane material with hardness less than <NUM>% with respect to the hardness of the first foamable polyurethane and/or thermoplastic polyurethane material so that said hull-shaped portion (<NUM>) of the first supporting element (<NUM>) accommodates, at least partially, said second foamable polyurethane and/or thermoplastic polyurethane material to make a second supporting element (<NUM>) coupled to the first supporting element (<NUM>).