EP4663061A2

EP4663061A2 - Antifatigue safety shoe

Info

Publication number: EP4663061A2
Application number: EP25212646.1A
Authority: EP
Inventors: Pier Franco Uzzeni
Original assignee: U Power Group SpA
Current assignee: U Power Group SpA
Priority date: 2018-07-06
Filing date: 2019-07-03
Publication date: 2025-12-17
Also published as: HRP20251618T1; RS67685B1; EA202190123A1; ES3057589T3; SI3817615T1; FI3817615T3; PL3817615T3; LT3817615T; DK3817615T3; EP3817615A1; EP4663061A3; PT3817615T; WO2020008393A1; IT201800006999A1; EP3817615B1

Abstract

The present invention relates to an antifatigue safety shoe (1), comprising an upper (2), provided, at the shoe toe, with a safety toe cap (4) and a layered sole (3) associated with said upper (2), said layered sole (3) comprising a lower layer (5) adapted to come into contact with the ground, an intermediate layer (6) associated with said upper (2) and with said 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.

Description

The present invention relates to an antifatigue safety shoe.
Safety shoes or accident-prevention shoes are known in the art which are able to offer the user a high degree of protection should accidental events occur.
These shoes must comply with stringent standards in order to be considered accident-prevention shoes. In fact, they must currently comply with the EN ISO20344 and EN ISO20345 standards.
As it is known, in order to comply with the standards in force on the subject, all safety shoes 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.
Since these are work shoes, they are meant to be worn by the user continuously for several hours a day.
Safety shoes are currently known which are provided 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 safety shoes to be worn 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, 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 safety 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 safety 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 safety 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 safety shoe that is also 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 safety 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 safety 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 safety shoe according to the invention;
figure 2 is an exploded side view of the antifatigue safety shoe of figure 1, according to the invention;
figure 3 is a plan view from above of the sole of the antifatigue safety shoe of figure 1, according to the invention.

With reference to the aforementioned figures, an antifatigue safety shoe, generally indicated with the reference numeral 1, comprises an upper 2 provided, at the shoe toe, with a safety toe cap 4 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 antifatigue insert 7 extends over substantially the whole sole of the antifatigue safety shoe 1.
As shown in figure 3, in particular, the antifatigue insert 7 extends over the whole sole of the antifatigue safety shoe 1, except for the shoe toe portion 40 where the safety toe cap 4 is housed.
Advantageously, the antifatigue insert 7 has a thickness of at least 8 millimetres at the rear zone P of the safety 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 safety 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 safety shoe 1, i.e. substantially at the toe 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.
As illustrated in the accompanying figures, the antifatigue insert 7 can be embedded, at least laterally and below, in the intermediate layer 6, possibly with the exception of 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 antifatigue safety 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 of 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 with 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 for safety shoes is the simple presence of a safety toe cap 4, the safety shoe 1 is advantageously equipped with a safety toe cap 4 provided 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, this upper layer 9 comprises, or is directly defined by, an anti-perforation lamina.
Advantageously, this anti-perforation lamina 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, as shown in the accompanying figures, the upper layer 9 is constituted by an anti-perforation lamina placed at the top in direct contact with the antifatigue insert 7.
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.
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 with which the antifatigue insert 7 is made advantageously has a density, measured according to the ISO 845 method, comprised between 300 and 360 Kg/m³, preferably between 320 and 360 Kg/m³, and still more preferably about 340 Kg/m³.
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 with 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 with 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 safety shoe 1 to have the same ergonomic antifatigue properties that ergonomic antifatigue mats feature.
In practice, it has therefore been found that the antifatigue safety 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 safety 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 safety 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.

Claims

Antifatigue safety shoe (1), comprising an upper (2), provided, at the shoe toe, with a safety toe cap (4) and a layered sole (3) associated with said upper (2), said layered sole (3) comprising a lower layer (5) adapted to come into contact with the ground, an intermediate layer (6) associated with said upper (2) and said lower layer (5), respectively, and an upper layer (9), characterized in that in said intermediate layer (6), an antifatigue insert (7) is embedded, having an average transversal thickness of at least 6 millimetres and adapted to unload the weight of the user under static conditions.
Antifatigue safety shoe (1), according to claim 1, characterized in that said antifatigue insert (7) extends over substantially the whole sole of said antifatigue safety shoe (1).
Antifatigue safety shoe (1), according to claim 1 or 2, characterized in that said antifatigue insert (7) has a thickness of at least 8 millimetres at the rear zone of said antifatigue safety shoe (1), a thickness of at least 6 millimetres at the middle zone of said antifatigue safety shoe (1), a thickness of at least 4 millimetres at the front zone of said antifatigue safety shoe (1).
Antifatigue safety shoe (1), according to one or more of the preceding claims, characterized in that said intermediate layer (6) comprises a plurality of windows (12) distributed along the lateral surfaces of said intermediate layer (6) between said rear zone and said front zone of said antifatigue safety shoe (1), said antifatigue insert (7) exposing lateral surfaces thereof through said windows (12).
Antifatigue safety shoe (1), according to one or more of the preceding claims, characterized in that said lower layer (5) is made of a polyurethane material, a nitrile material or a combination of said two materials.
Antifatigue safety shoe (1), according to one or more of the preceding claims, characterized in that said antifatigue insert (7) is made of a material comprising at least one polyol polymer.
Antifatigue safety shoe (1) according to one or more of the preceding claims, characterized in that said antifatigue insert (7) is made of a bicomponent material comprising a polyol polymer and an isocyanate.
Antifatigue safety shoe (1) according to one or more of the preceding claims, characterized in that said polyol polymer is a polyol polyester.
Antifatigue safety shoe (1) according to one or more of the preceding claims, characterized in that said polyol polymer is a polyether polyol.
Antifatigue safety shoe (1) according to one or more of the preceding claims, characterized in that said isocyanate is a diphenylmethane diisocyanate.
Antifatigue safety shoe (1) according to one or more of the preceding claims, characterized in that said lower layer (5) comprises a base (50) and a plurality of projections (51) projecting with respect to said base (50), said projections (51) being made of a material having a substantially lower density than the density of the material in which said base (50) is made.
Antifatigue safety shoe (1) according to one or more of the preceding claims, characterized in that said antifatigue insert (7) is made of non-expanded polyurethane.
Antifatigue safety shoe (1), according to one or more of the preceding claims, characterized in that said antifatigue insert (7) extends over the whole sole of said antifatigue safety shoe (1), except for the shoe toe portion (40) where the safety toe cap (4) is housed.
Anti-fatigue safety shoe (1), according to one or more of the claims from 2 to 13, characterized in that said upper layer (9) is constituted by an anti-perforation lamina that completely covers said antifatigue insert (7) and extends substantially along the entire length of said intermediate layer (6), so as to completely cover the sole of the foot of the user wearing the shoe.
Anti-fatigue safety shoe (1), according to one or more of the preceding claims, characterized in that said upper layer (9) is constituted by an anti-perforation lamina placed above in direct contact with said antifatigue insert (7).
Anti-fatigue safety shoe (1), according to one or more of the claims, characterized in that said antifatigue insert (7) is made of a material having a resilience lower than 35% and preferably comprised between 15% and 30%.
Anti-fatigue safety shoe (1), according to one or more of the preceding claims, characterized in that said antifatigue insert (7) is made of a material having a density comprised between 320 and 360 Kg/m³, preferably of about 340 Kg/m³.