OBTAINED"

DESCRIPTION

Field of the invention

The invention which is the subject matter of the present patent application applies to the field of footwear manufacturing, particularly but not exclusively safety footwear.

In particular, the invention which is the subject matter of the present patent application relates to a process for manufacturing footwear sole and product thus obtained.

According to the invention which is the subject matter of the present patent application, the process includes a first step of injecting polyurethane (PU), a following step of gluing an insert made up of elastic material with shape memory and a final step including a second injection of polyurethane (PU).

Description of prior art

As it is known, safety footwear is a personal protective equipment suitable for protecting the foot against aggressive external factors and are made up of

- an upper, made of various materials, suitable for wrapping the foot at its upper and side part, which usually also has the breathability function;

- a protective toecap made of steel or of composite material;

- a stiff counter;

- a sole or outsole, made of various materials so as to obtain specific resistances.

Given the specific use for which safety footwear is intended, safety requirements according to the current regulations must be met, in order to guarantee its use in all conditions of risk to which the worker is subjected.

It is known that safety footwear uses a mounting insole made up of anti-perforation fabric with one or more layers or a mounting insole with integrated stainless-steel sheet. The mounting insole made of anti-perforation fabric with one or more layers or the mounting insole with integrated stainless-steel sheet have to pass perforation resistance tests required by the compulsory regulations in order to guarantee the protection of the whole sole of the foot against external bodies and sharp objects, such as nails and/or similar objects.

The main disadvantage of safety footwear thus made and described is that they tend to have a heavier and less flexible sole. Conventionally, the sole of a piece of footwear can be made in two ways: by means of pressing or by means of injection process. Manufacturing by means of pressing:

According to the manufacturing process by means of pressing, the sole is made of EVA or of rubber, and subsequent pressing so as to obtain the shape of the sole which is then glued to the upper. Manufacturing by means of injection:

According to the manufacturing process by means of injection, the material, conventionally polyurethane or a mixture of polyurethanes with different density, is injected in a mold opportunely made, so as to form the final sole by means of a single passage.

Typically, the sole made by means of the described process is heavy and little flexible and therefore it is less comfortable for the end user.

In the state of the art, processes suitable for manufacturing soles of footwear by means of molding techniques are known.

For example, the document US2003182820 describes the manufacturing of a sandal provided with toecap for the protection of the fingers and relative manufacturing process.

In particular, the structure of the sandal described in the document US2003182820 includes a rubber shaped sole configured for supporting a lower surface of a foot comprising a heel, a midfoot and a forefoot, a toecap extending from the sole and configured to cover an upper part of at least one portion of the forefoot, said toecap being obtained by means of molding and being integral with the sole itself and a plurality of straps for sandals fixed to the sole to retain the sandal on the foot, at least one of the sandal straps being joined to the toecap.

In accordance with what specified in the document US2003182820 the process for manufacturing the shaped sole, which includes the toecap extending from said sole, aiming at covering the upper part of the forefoot, comprises the following steps:

- positioning the material in a mold suitably shaped for manufacturing the sole, said mold being pivotally connected to a first plate having the outer shape of the toecap,

- closing the first plate having the outer shape of the toecap on the mold into which the material has been inserted,

- inserting the material into a second suitably shaped plate for replicating the shape of the toecap, said second plate being pivotally joined to the first plate.

The described process exclusively relates to the manufacturing of the sole integrated with the toecap, whereas the further elements making up the sandal are separately manufactured and joined to the "sole/toe cap" structure in accordance with known art.

The obtained structure thus needs then to be integrated, according to the known art, with the elements "inner sole - midsole" as well as the necessary structure for completing the sandal.

Summary of the invention

Aim of the invention which is the subject matter of the present patent application is to obtain a piece of footwear provided with a lighter sole compared to the common soles for safety footwear.

This aim is reached by the invention which is the subject matter of the present patent application, in particular by means of a process for manufacturing the sole which is divided into separate steps comprising :

- a first polyurethane injection for manufacturing the outsole of the piece of footwear,

- the gluing of an insert made of material with shape memory,

- a second polyurethane injection for manufacturing the side profile of the sole,

- completion of the piece of footwear. According to the invention which is the subject matter of the present patent application, the insert made of elastic material with shape memory is made of a lighter material with respect to the polyurethanes used for the first and third step.

In particular, since the insert is made of elastic material joined by means of gluing and not by means of injection, the manufactured end product is much lighter and more flexible, with respect to the products manufactured according to the known art and much more comfortable for the user, with respect to the products manufactured according to the known art.

In a preferred, but not binding, embodiment, the process which is the subject matter of the present patent application is carried out by means of an opportunely improved device.

Brief description of the drawings

Fig 1: Graphic example of the product obtained according to the invention which is the subject matter of the present patent application;

Fig 2: Schematic example of the process for manufacturing a sole according to the invention which is the subject matter of the present patent application.

Fig 3 - Fig 3.1: Graphic example of a manufacturing form of the insert.

Fig 4 - Fig 4.1: Graphic example of a manufacturing form of the insert.

Fig 5 - Fig 5.1: Graphic example of a manufacturing form of the insert.

Fig 6: graphic example of the mold for manufacturing the piece of footwear;

Fig 77.1: Graphic example of a first preferred manufacturing form of the process for joining insert /outsole and side profile/insert/outsole;

Fig 8 8.1: Graphic example of a second manufacturing form of the process for joining insert/outsole and side profile/insert/outsole; Fig 9 9.1: Graphic example of a third manufacturing form of the process for joining insert/outsole and side profile/insert/outsole; Fig 10 Graphic example of a sole obtained according to the process which is the subject matter of the present patent application. Detailed description of the invention

With reference to the enclosed Figures, the sole (1) for footwear is manufactured according to the process which is the subject matter of the present patent application (Fig 2), which includes the following steps:

- manufacturing the insert in elastic material with shape memory (Step A Fig 2 Tab 1);

- Inserting the insert made of elastic material with shape memory obtained in the first step into a second body opportunely improved (Step B Fig 2, Tab 1) wherein the upper of a piece of footwear has been previously inserted;

- Manufacturing the outsole of the piece of footwear (Step C Fig 2, Tab 1);

- Manufacturing the side profile of the sole (Step D Fig 2, Tab i);

- Completing the configuration of the piece of footwear. According to the invention which is the subject matter of the present patent application, the first step of the process which is the subject matter of the present patent application provides the manufacturing of an insert (13) made of elastic material with shape memory.

In a preferred, but not-binding, embodiment, the manufacturing of the insert made of elastic material with shape memory (Fig 2, 13) occurs by means of injection in a generic mold.

In a preferred, but not exclusive, embodiment the manufacturing of the insert made of elastic material with shape memory (13 Fig 2) occurs by means of injection of a material selected from a range of various materials having greater lightness characteristics with respect to the polyurethane (PU), material which is usually used for manufacturing soles. The material used could be thermoplastic polyurethane (TPU) or foam rubber, which will make the sole (1) lighter. With reference to Fig 3, Fig 3.1, Fig 4, Fig 4.1, Fig 5, Fig 5.1 Tab 2 the insert (13) has an upper surface (13.1) and a lower surface (13.2).

With reference to Fig 3 and Fig 3.1, in a first preferred embodiment, the area of the lower surface (13.2) of the insert (13) is greater than the area of the upper surface (13.1).

According to the first preferred, but not exclusive, embodiment the lower surface of the insert made of material with shape memory (13) has therefore, along its entire perimeter, a strip (20) determined by the difference of the lower surface (13.2) with respect to the upper surface (13.1).

With reference to Fig 4 and Fig 4.1, in a second preferred embodiment, the area of the lower surface (13.2) of the insert (13) is smaller than the area of the upper surface (13.1).

According to this second preferred embodiment, the upper surface of the insert (13) has, along its entire perimeter, a surface strip (21) determined by the difference of the upper surface (13.1) with respect to the lower surface (13.2).

With reference to Fig 5 and Fig 5.1, in a third preferred embodiment both the upper surface (13.1), and the lower surface (13.2) have strips (20, 21), as a result along the entire perimetric surface of the insert (13) there is a recess (22) developing along the entire thickness of the insert (13) between the lower surface (13.2) and the upper surface (13.1), said upper (13.2) and lower (13.1) surface having the same size.

According to the invention which is the subject matter of the present patent application, the subsequent process steps (B, C, D Fig 2) involve the use of a suitably improved device (9).

In particular, the device (9) is made up of a first body (9.1) including an essentially flat surface provided with a central passing-through opening replicating the shape of an insole, said first body (9.1) being pivotably joined at one side to a second body (9.2, Fig 6) through a pivoting joining means (10). In particular, the second body (9.2) is in turn made up of an essentially flat surface provided with a central passing-through shaped opening replicating the shape of the insert (13).

In particular, the pivoting joining means (10) is placed at the sides of the first body (9.1) and of the second body (9.2) so as to allow a pivoting movement of the first body (9.1 Fig 6) towards the second body (9.2, Fig 6) keeping engaged the sides of each first (9.1) and second (9.2) body to which the joining means (10) is joined.

With reference to Fig 2, the second body (9.2) is in turn pivotably joined to a third body (9.3) by means of the same pivoting joining means (10).

In particular, the third body (9.3) is made up of a mold in which the shape for manufacturing an outsole (14, Fig 2) is obtained.

In particular, the pivoting joining means (10) is joined to the mold (9.3, Fig 2, Fig 6) so as to allow a pivoting movement of the second body (9.2) or of the "first body (9.1) - second body (9.2)" assembly towards the mold (9.3) keeping engaged the sides to which the joining means (10) is joined.

In a preferred, but not-binding, embodiment the joining means (10) pivotally joining the first body (9.1) to the second body (9.2) and the second body (9.2) to the mold (9.3) is of the hinge type with pin.

According to the foregoing, the first body (9.1), the second body (9.2), the mold (9.3) and the joining means (10) form a device (9, Fig 6 table 3) through which the following steps occur

- inserting the insert made of elastic material with shape memory (Step B Fig 2, Tab 1);

- manufacturing the outsole of the piece of footwear (Step C Fig 2, Tab 1) and

- manufacturing the side profile of the sole (Step D Fig 2, Tab 1). for manufacturing the sole (1) of the piece of footwear.

In particular, an upper (11, Fig 6 Tab 3), previously joined to a mounting insole (12, Fig 6 Tab 3), is inserted into the passing- through opening of the first body (9.1, Fig 6 Tab 3). According to the invention subject of the present patent application, the insert (13) is inserted into the passing-through opening of the second body (9.2), said second body being pivotably joined to a side of the first body (9.1).

In a preferred embodiment, the manufacturing step of the outsole of the piece of footwear (Step C Fig 2, Tab 1) occurs by means of injection in the mold of polyurethane in liquid form (9.3).

Once the injection step for manufacturing the outsole (14) is completed, the second body (9.2), into which the insert (13) is inserted on whose lower surface (13.2) a layer of adhesive material has been moved, is caused to pivot over the mold (9.3).

According to the foregoing, in a first embodiment (Fig. 3, 3.1 Tab 2, Fig 7 Tab 4), the insert (13) has a lower surface (13.2) greater than the upper surface (13.1) and therefore during the step of positioning the second body (9.2) on the mold (9.3) the liquid polyurethane sticks to the lower surface of the insert which had been previously covered with a layer of adhesive material so as to create a single "outsole (14) - insert (13)" body.

With reference to Fig 7, according to the preferred embodiment described, the presence of the strip (20) prevents the liquid polyurethane from coming out of the mold (9.3) and from going up along the sides of the insert (13), preventing it from impregnating the sides of the insert (13).

With reference to Fig 8 and Fig 8.1, in a second embodiment (Fig 4, 4.1 Tab 2, Fig 8 Tab 4) the insert (13) has a lower surface (13.2) smaller than the upper surface (13.1) and therefore during the step of pivoting the second body (9.2) on the mold (9.3), the liquid polyurethane sticks to the lower surface of the insert, previously covered with a layer of adhesive material, creating a single "outsole (14) / insert (13)" body.

A possible excess of cast polyurethane along the sides of the insert (13) can be eliminated once the step of manufacturing the sole (1) is completed.

With reference to Fig 9 and Fig 9.1, in a third preferred embodiment

(Fig 5, 5.1 Tab 2, Fig 9 Tab 4) the insert (13) has a recess (22) along its perimetric surface which develops along the entire thickness of the insert (13) between the lower surface (13.2) and the upper surface (13.1).

The strip of the lower surface (20 Fig 5.1) prevents the liquid polyurethane, during the step of positioning the second body (9.2) on the mold (9.3), from coming out of the mold (9.3) and from also going into the recess (22), gluing therefore only to the lower surface (13.2) of the insert (13), which had been previously covered with a layer of adhesive material so as to create a single "outsole

(14) - insert (13)" body.

Once the second body (9.2) is placed on the mold (9.3), on the upper surface (13.1) of the insert (13) a second injection (Fig 2, D) of liquid polyurethane is carried out for realizing the side profile

(15) of the sole (1) so as to create a single "side profile (15) - insert (13) - outsole (14)" body.

The injected polyurethane for manufacturing the side profile (15) of the sole (1) adheres to the upper surface (13.1) of the insert (13) which had been previously covered with a layer of adhesive material, while it adheres to the front part of the outsole (14) in a natural way as the liquid polyurethane adheres to the side upper and to the outsole while it adheres to the insert (13) by means of the glue previously applied on the surface of the insert (13).

With reference to Fig 7 and Fig 7.1, according to the first embodiment, the insert (13) has an upper surface (13.1) smaller than the lower surface (13.2).

The liquid polyurethane sticks to the upper surface of the insert, previously covered with a layer of adhesive material.

A possible excess of cast polyurethane along the sides of the insert (13) for manufacturing the side profile (15) can be eliminated once the step for manufacturing the sole (1) is completed.

With reference to Fig 8 and Fig 8.1, in a second embodiment (Fig 4, 4.1 Tab 2, Fig 8.1 Tab 4), the insert (13) has an upper surface (13.1) greater than the lower surface (13.2).

The liquid polyurethane sticks to the upper surface of the insert, previously covered with an adhesive material layer. The presence of the strip (21) on the upper surface (13.1) of the insert (13) prevents the liquid polyurethane from running along the sides of the insert (13) and of the outsole (14).

With reference to Fig 9 and Fig 9.1, in a third preferred embodiment (Fig 5, 5.1 Tab 2, Fig 9.1 Tab 4), the insert (13) has, along its perimetric surface, a recess (22) developing for the entire thickness of the insert (13) between the lower surface (13.2) and the upper surface (13.1). The strip of the upper surface (21 Fig 9.1) prevents the liquid polyurethane from also running into the recess (22), gluing therefore only to the upper surface (13.1) of the insert (13), which had previously been covered with a layer of adhesive material. Once the second injection of liquid polyurethane is complete, the first body (9.1) is pivoted and therefore superimposed to the second body (9.2)/mold(9.3) assembly.

Consequently, by the pressure of the first body (9.1) on the "second body (9.2)/mold (9.3) assembly, the expansion of the polyurethane and the manufacturing of the side profile (15) of the sole (1) are obtained.

By acting according to the foregoing, regardless of the preferred embodiments, the upper (11) joined to the mounting insole (12) is joined to the injected liquid polyurethane and contextually the manufacturing of the side profile (15) of the sole (1) is obtained, with the manufacturing of the end piece of footwear (1, Fig 10).