The present invention relates to a professional work shoe.

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

The safety shoes therefore comprise an upper provided, at the shoe toe, with a sufficiently structured, and therefore rigid, safety toe cap 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, safety shoes are known which are provided with a layered sole comprising in their inside an insert made of an elastic material, for example of the type of thermoplastic expanded polyurethane, adapted to make walking more comfortable and in general all the activities in which the user is in continuous movement, thanks to the return of energy and the soft and dynamic cushioning given by the elastic insert itself.

Such safety shoes of the known type, however, are not free from drawbacks, including the fact that the insertion of an elastic insert inside the layered sole entails a greater complexity of the operations for manufacturing the finished product, and consequently an increase in the production costs.

The task of the present invention is to provide a professional work shoe which guarantees a high level of comfort for the user, in particular during the movement activities, and which is also easy and inexpensive to manufacture at the same time if compared to the known technique .

Within the scope of this task, an object of the present invention is to provide a professional work shoe that is capable of providing the broadest guarantees of reliability and safety when used.

The task disclosed above, as well as the objects mentioned and others which will become apparent as follows, are achieved by a professional work shoe as described in claim 1.

Other characteristics are set out in the dependent claims .

Further features and advantages shall result more apparent from the description of a preferred, but not exclusive, embodiment of a 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 a professional work shoe according to the invention;

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

figure 3 is a section view of the layered sole of the professional work shoe shown in Figure 1 taken along a vertical longitudinal and median plane.

With reference to the above figures, the professional work shoe, generally indicated with the reference number 1, comprises an upper 2 and a layered sole 3 associated with the upper 2. Such layered sole 3 comprises a lower layer 5, i.e. a tread, 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, the intermediate layer 6 is made of polyurethane having a resilience greater than 41%.

This resilience value greater than 41% is measured according to the measurement standard DIN 53512, ("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 .

This resilience value of the polyurethane of which the intermediate layer 6 is made therefore confers to the professional work shoe 1 good characteristics of elastic return of the walking energy, thus reducing the user's fatigue during the movement activities without resorting to complex and expensive procedures for inserting special elastic inserts.

Advantageously, the intermediate layer 6 is made of polyurethane having a hardness comprised between 30 and 45 Shore A, preferably comprised between 37 and 41 Shore A.

As shown in particular in Figure 3, the intermediate layer 6 of the layered sole 3 extends over the entire support surface of the foot and is completely and exclusively made of said polyurethane having a resilience greater than 41%.

Advantageously, moreover, the intermediate layer 6 is made of polyurethane having a molding density of less than 0.43 g/cm ³ .

Preferably the molding density of said polyurethane is comprised between 0.37 and 0.41 g/cm ³ depending on the environmental molding conditions relatively in particular to the environmental temperature and the environmental humidity level. Under optimal environmental conditions the molding density of said polyurethane is equal to 0.39 g/cm ³ .

The use of a polyurethane having a molding density of less than 0.43 g/cm ³ gives a good lightness to the layered sole 3 and therefore to the shoe 1 as a whole.

The resilience greater than 41% and the molding density of less than 0.43 g/cm ³ of the polyurethane of which the intermediate layer 6 of the layered sole 3 is made allow obtaining a light and performing professional work shoe 1 from the point of view of the dynamic properties and therefore pleasant and comfortable to wear and use over prolonged periods. Advantageously, the upper 2 can be provided, at the toe, with a safety toe cap 4, so that the shoe 1 can also meet the current safety regulations, and in particular the standards EN ISO 20344 and EN ISO 20345.

The safety toe cap 4 can be provided with holes and comprise a protective membrane 11 provided to close the aforesaid holes, in order to ensure at the same time perspiration and protection of the user's foot.

Advantageously, the lower layer 5 can be made of polyurethane having a molding density of less than 0.90 g/cm ³ .

The use of polyurethane also for the lower layer 5, as well as for the intermediate layer 6, allows facilitating the operations for manufacturing the sole 3 itself, thanks to the chemical /physical compatibility of the two materials.

Advantageously, the upper layer 9 can comprise, or can be made up of, an anti-perforation lamina.

Advantageously, the polyurethane of which the intermediate layer 6 is made has a tensile strength, measured according to the measurement method DIN 53504, comprised between 3.5 and 5 MPa, preferably comprised between 4.2 and 4.8 MPa, and/or an elongation at break, measured according to the measurement method DIN 53504 comprised between 350 and 500%, and preferably comprised between 350 and 380%.

Advantageously, the intermediate layer 6 has a thickness of not less than 3 mm.

This minimum thickness of 3 mm of the intermediate layer 6 is such as to allow the material of which the intermediate layer 6 is made, i.e. polyurethane with a resilience greater than 41%, to exert its function of returning energy to the user during walking or in general during dynamic activities.

Advantageously, the intermediate layer 6 has a thickness of at least 10 mm at the rear zone P of the shoe 1, preferably equal to about 13 mm.

Advantageously, the intermediate layer 6 has a thickness of at least 3 mm at the central zone C of the shoe 1, preferably equal to about 3.5 mm.

Advantageously, the intermediate layer 6 has a thickness of at least 5 mm at the front zone A of the shoe 1, preferably equal to about 6mm.

These minimum thicknesses of the intermediate layer 6 are such as to allow the material of which the intermediate layer 6 is made, i.e. polyurethane with a resilience greater than 41%, to exert an optimal return of the walking energy, increasing the effect of energy return primarily at the user's heel, where most of the energy is discharged in the impact phase of the foot on the ground and where the thicknesses are greater, and secondly at the user's toe, where the return of the energy is required to favour the subsequent thrust of the forefoot. The smaller thicknesses are instead present at the central zone C of the shoe 1, between the heel and the toe of the user's foot.

It has in practice been noted that the professional work shoe, according to the present invention, fulfils the task as well as the predefined objects as it is comfortable to wear and to use, even over prolonged periods of dynamic activity, while being simple and inexpensive to manufacture.

Another advantage of the professional work shoe, according to the invention, is that it guarantees the user a significant return of energy during walking without resorting to the introduction of particular elastic inserts in the sole.

The 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.

In practice, any materials can be used according to requirements, as long as they are compatible with the specific use, the dimensions and the contingent shapes.