The present invention relates to an antifatigue professional work shoe.

Antifatigue professional work shoes are known in the art which are able to offer the user a desired degree of protection should accidental events occur.

As it is known, professional work shoes must comply with stringent standards, including:

• EN ISO 20345, relating to safety footwear with 200 J toe cap resistance;

• EN ISO 20346, relating to safety footwear with 100 J toe cap resistance;

• EN ISO 20347, relating to work or professional footwear without any specific toe cap resistance ;

• EN ISO 20344, relating to test methods and general requirements.

In particular, in order to be able to define shoes as "safety" or accident-prevention shoes, the professional work shoes must be equipped with a safety toe cap and therefore comply with the EN ISO 20344, EN ISO 20345 and EN ISO 20346 standards.

The safety shoes therefore comprise an upper provided with a sufficiently structured, and therefore rigid, safety toe cap at the shoe toe to withstand impacts or crushing, protecting the user's foot.

In general, since these are work shoes, they are meant to be worn by the user continuously for several hours a day.

Currently, professional work shoes are known which are equipped with a layered sole internally comprising an insert made of an elastic material adapted to make placing the foot on the ground more comfortable during walking and in general during all the activities in which the user moves continuously.

For example, footwear is known in the state of the art which comprises a sole provided with an elastic insert made of thermoplastic polyurethane foam, which provides a soft and dynamic cushioning that returns energy during movements.

However, many work activities which require professional work shoes to be worn, both for safety and not, do not require the frequent movement of the operator from one place to another.

On the contrary, the operator is often required to work standing up, still in his own workstation, for example in front of a work bench or a conveyor belt.

As it is known, however, maintaining an upright position for prolonged periods involves causing stress and discomfort to the musculoskeletal system.

In particular, when standing still in an upright position the weight of the body exerts pressure on all the main muscles of the spine, the lumbar area, the legs and the feet. Consequently the maintenance of the upright position for prolonged periods is often the cause of pain, contractures and stiffness, both muscular and articular, as well as a reduction in blood circulation, particularly in the lower limbs where blood tends to stagnate .

In order to try to prevent these undesirable effects caused by maintaining an upright position for prolonged periods, so-called ergonomic antifatigue mats are often installed in workplaces, which are made with materials and thicknesses that provide an optimal balance between compression and resistance for the operator standing on them. In fact, these mats allow the muscular effort to be distributed evenly, relieving the stress on ligaments, joints and muscles, while absorbing and dispersing the micro-shocks to which the musculo skeletal system is subjected, even in the limited movements that occur while maintaining the standing position. Furthermore, the ergonomic antifatigue mats allow stimulating blood circulation in the lower limbs and the lower back.

However, the installation of ergonomic mats in workplaces, and in particular in all places where operators perform their work activities while standing for long periods, is complex and expensive, as it requires important work retrofitting interventions and as it involves very large areas of industrial plants.

Furthermore, the ergonomic antifatigue mats must continuously be subjected to maintenance and cleaning in order to ensure the necessary safe working conditions for the operators.

Furthermore, the ergonomic antifatigue mats are subject, also because of their exposure to external agents, to the decay of the antistatic properties that they generally possess when they are newly installed.

The aim of the present invention is to provide an antifatigue professional work shoe which allows ensuring the wearer a high level of comfort, particularly in conditions of prolonged standing.

Within the scope of this aim, an object of the present invention is to provide an antifatigue shoe that has the same ergonomic features for the wearer as those provided by ergonomic antifatigue mats.

A further object of the invention is to provide an antifatigue shoe that is capable of providing the broadest guarantees of reliability and safety when used.

Another object of the invention is to provide an antifatigue shoe that is easy to make and is economically competitive when compared with the Prior Art.

The aim disclosed above, as well as the objects mentioned and others which will become better apparent hereinafter, are achieved by an antifatigue professional work shoe as described in claim 1.

Other characteristics are provided in the dependent claims .

Further features and advantages shall be more apparent from the description of a preferred, but not exclusive, embodiment of an antifatigue professional work shoe, illustrated merely by way of non-limiting example with the aid of the accompanying drawings, in which :

figure 1 is an overall side elevation view of an antifatigue shoe according to the invention;

figure 2 is an exploded side view of the antifatigue shoe of figure 1, according to the invention;

figure 3 is a plan view from above of the sole of the antifatigue shoe of figure 1, according to the invention .

With reference to the above figures, a professional work shoe, generally indicated with the reference numeral 1, comprises an upper 2 and a layered sole 3 associated with the upper 2. The layered sole 3 comprises a lower layer 5 adapted to come into contact with the ground, an intermediate layer 6 associated with the upper 2 and with the lower layer 5, respectively, and an upper layer 9.

According to the invention, in the intermediate layer 6, an antifatigue insert 7 is inserted, having an average transversal thickness of at least 6 millimetres adapted to unload the weight of the user under static conditions .

Advantageously, the upper 2 is provided, at the shoe toe, with a safety toe cap 4.

The presence of a safety toe cap 4, in compliance with the standard EN ISO 20345, i.e. with a resistance of 200 J, makes the professional work shoe a so-called "safety" work shoe.

The presence of a safety toe cap 4, in compliance with the standard EN ISO 20346, i.e. with a resistance of 100 J, makes the professional work shoe a so-called "protective" work shoe.

In the absence of the safety toe cap 4, the shoe is still a professional work shoe, as it complies with EN ISO 20347.

Advantageously, the antifatigue insert 7 extends over substantially the whole sole of the antifatigue professional work shoe 1.

As shown in figure 3, in particular, the antifatigue insert 7 extends over the whole sole of the antifatigue professional work shoe 1, except for the shoe toe portion 40 where the safety toe cap 4 is housed, where present.

Advantageously, the antifatigue insert 7 has a thickness of at least 8 millimetres at the rear zone P of the shoe 1, i.e. substantially at the heel of the user ' s foot .

Advantageously, the antifatigue insert 7 has a thickness of at least 6 millimetres at the middle zone

C of the shoe 1, i.e. substantially at the arch of the user ' s foot .

Advantageously, the antifatigue insert 7 has a thickness of at least 4 millimetres at the front zone A of the shoe 1, i.e. substantially at the tip of the user ' s foot .

In this way the static support effect provided by the antifatigue insert 7 is accentuated at the user's heel, where the weight of the same is most unloaded, and gradually decreasing towards the user's toes.

The antifatigue insert 7 can be embedded, at least laterally and below, in the intermediate layer 6.

The antifatigue insert 7 can be completely embedded, below, above and laterally, in the intermediate layer 6, possibly with the exception of only some lateral portions thereof exposed through lateral windows 12, where present, as explained below.

Advantageously, the intermediate layer 6 comprises a plurality of windows 12 distributed along the lateral surfaces of the intermediate layer 6 between the rear zone P and the front zone A of the shoe 1, so that the antifatigue insert 7 exposes its lateral surfaces thereof through said windows 12.

The windows 12 provided on the lateral surfaces of the intermediate layer 6 make the antifatigue insert 7 located inside the intermediate layer 6 itself visible, and at the same time also perform the technical function of allowing the deformation towards the outside of the material with which this antifatigue insert 7 is made, so as to accommodate the deformation of the material following the compression imposed by the operator while standing in an upright position and thus unloading the operator's weight under static conditions.

Advantageously, the intermediate layer 6 is made of a polyurethane material, such as for example a low- density polyurethane foam.

Advantageously, the lower layer 5 is made of a polyurethane material, a nitrile material or a combination of these two materials.

The lower layer 5 can for example be made of a compact high-density polyurethane material, or of a thermoplastic polyurethane material, or still of a nitrile rubber.

Advantageously, the lower layer 5 comprises a base 50 and a plurality of projections 51 projecting with respect to the base 50. These projections 51 can be made of a material having a density substantially lower than the density of the material of which the base 50 is made.

Advantageously, the components of the layered sole 3 are made of antistatic materials, in order to guarantee antistatic properties to the shoe 1.

Alternatively, the components of the layered sole 3 can be made of dielectric materials, in order to guarantee insulating properties to the shoe 1.

Advantageously, the lower layer 5 has anti-slip properties .

In the case wherein the aforementioned lower- density projections 51 are present, this anti-slip property of the lower layer 5 of the layered sole 3 is further increased.

Despite the fact that the minimum requirement established by the standards EN ISO 20345 and EN ISO 20346 for safety shoes is the simple presence of a safety toe cap 4, the shoe 1 is advantageously provided with a safety toe cap 4 equipped with holes configured to guarantee the transpiration of the foot. Preferably, moreover, a protective membrane 11 is provided for closing the holes present on the cap 4, so as to allow both the transpiration and the protection of the user's foot .

Advantageously, the upper layer 9 completely covers the antifatigue insert 7.

Advantageously, the upper layer 9 comprises, or is directly defined by, an anti-perforation lamina.

If the upper layer 9 consists exclusively of an anti-perforation lamina, the top of the antifatigue insert 7 is in direct contact with this anti-perforation lamina .

Advantageously, the upper layer 9 comprises, or is directly defined by, an insole having a thickness comprised between 1 and 3 millimetres, preferably of about 2 millimetres, without anti-perforation properties .

If the upper layer 9 is exclusively constituted by this type of insole, the top of the antifatigue insert 7 is in direct contact with this insole.

Alternatively, the antifatigue insert 7 can be covered at the top by an upper layer 9 made of the same material as the intermediate layer 6, which may also be further surmounted by an anti-perforation lamina or by an insole. In this way the antifatigue insert 7 is completely embedded in the material of which the intermediate layer 6 and the upper layer 9 are made.

Advantageously, the intermediate layer 6 can lack lateral windows so that the antifatigue insert 7 is not visible and/or not accessible from the outside.

In this way the protection of the antifatigue insert 7 itself from eventual external agents is further guaranteed .

Advantageously, the anti-perforation lamina 9 extends substantially along the entire length of the intermediate layer 6, so as to completely cover the sole of the foot of the user wearing the shoe.

Advantageously, therefore, the upper layer 9 consists of an anti-perforation lamina that completely covers the antifatigue insert 7 and extends substantially along the entire length of the intermediate layer 6, so as to completely cover the sole of the foot of the user wearing the shoe.

In this case the fact that the intermediate layer 6 comprises a plurality of windows 12 distributed along the lateral surfaces of the shoe 1, and such as to allow the deformation towards the outside of the material with which this antifatigue insert 7 is made, allows the antifatigue insert 7 to effectively exercise its function of absorbing the static load, compensating for the greater rigidity of the layered sole 3 given by the presence of the anti-perforation lamina.

The lateral windows 12 can also perform the same function in the case where an insole is present which is not of the anti-perforation type as described above, although it is generally less rigid than an anti perforation lamina.

This anti-perforation lamina is preferably made of non-metallic material, for example a resin-based polyester or similar material.

Advantageously, the antifatigue insert 7 is made of a material comprising at least one polyol polymer.

This polyol polymer is preferably a polyol polyester .

In an alternative embodiment, the polyol polymer can also be a polyether polyol.

Advantageously, the antifatigue insert 7 can be made of a bicomponent material comprising at least one polyol polymer, such as for example a polyol polyester or a polyether polyol, and an isocyanate.

Preferably the isocyanate is a diphenylmethane diisocyanate, and still more preferably a 4,4'- diphenylmethane diisocyanate.

The bicomponent material further comprises an amine catalyst .

Preferably, in particular in the case in which a polyol polyester is used, the amine catalyst is an aliphatic tertiary amine.

Advantageously, the bicomponent material comprises said polyol polyester polymer and said isocyanate in a ratio, respectively, of 100:54 parts by weight.

In the case of the alternative embodiment with polyether polyol, the bicomponent material comprises said polyether polyol polymer and said isocyanate in a ratio, respectively, of 100:52 parts by weight.

Advantageously, therefore, the antifatigue insert 7 is made of a polyurethane obtained from the polymerization of a polyol, preferably polyester, with an isocyanate which differs from the thermoplastic polyurethane foams mentioned in the introduction with reference to the known safety shoes due to a lower elasticity, also due to the absence of foaming agents.

Advantageously, therefore, the antifatigue insert 7 is made of a non-expanded polyurethane, preferably not of the thermoplastic type.

The material of which the antifatigue insert 7 is made advantageously has a density, measured according to the ISO 845 method, comprised between 300 and 360 Kg/m ³ , preferably between 320 and 360 Kg/m ³ , and still more preferably about 340 Kg/m ³ .

Moreover, this material has a "Shore A" hardness measured according to the DIN 53 505 method which is advantageously comprised between 20 and 25 and preferably equal to 22 or 23.

Furthermore, this material has a tensile strength, measured according to the DIN 53 504 method, advantageously comprised between 1.5 and 3.5 MPa, and preferably comprised between 2.8 and 3.0 MPa.

Furthermore, this material has an elongation at break, measured according to the DIN 53 504 method, comprised between 200 and 500%, and preferably greater than 400% .

Furthermore, the material of which the antifatigue insert 7 is made has a significantly lower resilience than the elastic inserts in thermoplastic polyurethane foam mentioned with reference to the known safety shoes.

In fact, the resilience of the antifatigue insert 7 is advantageously lower than 35%, and preferably comprised between 15% and 30%.

On the other hand, the resilience of the thermoplastic polyurethane foams used for the elastic inserts of known safety shoes is generally greater than 50% .

This resilience value can be measured according to the measurement standard DIN 53 512, ("Determining the rebound resilience of rubber using the Schob pendulum") and represents the relationship between the energy returned by an elastomer subjected to an impact and the energy applied to this elastomer in the same impact.

The resilience value of the material of the antifatigue insert 7 lower than 35% gives the safety shoe 1 a poor elastic restitution of energy in dynamic conditions, but a high lift in static conditions. The density values of the material of which the antifatigue insert 7 is made also contribute to this behaviour, as the hardness and/or tensile strength and/or elongation at break values as defined above do.

Advantageously, in the case in which the antifatigue insert 7 is made starting from polyol polyester, the absolute compatibility with the polyurethane material with which the intermediate layer 6 of the layered sole 3 is formed, where the antifatigue insert 7 is housed, and therefore the moulding and assembly procedures of the components that make the layered sole 3 itself, are particularly simplified.

The average thickness of at least 6 millimetres of the antifatigue insert 7, in combination with the materials with which this antifatigue insert 7 is made, as described above, allows the antifatigue shoe 1 to have the same ergonomic antifatigue properties that ergonomic antifatigue mats feature.

In practice, it has therefore been found that the antifatigue professional work shoe, according to the present invention, achieves the intended aim and objects, since it has ergonomic characteristics comparable to those of ergonomic antifatigue mats, but unlike ergonomic antifatigue mats it does not require expensive interventions for structural installation and subsequent maintenance.

Another advantage of the antifatigue shoe according to the invention is that the ergonomic action is exercised continuously over time as long as the operator is wearing the shoe, but also in any location, regardless of the nature of the ground on which the user places his feet .

The antifatigue professional work shoe thus conceived is susceptible to many modifications and variants, all falling within the same inventive concept; furthermore, all details can be replaced by technically equivalent elements. In practice, the materials used, as well as the dimensions, can be of any type according to the technical requirements.