Patent Application
20250107593
The present invention relates to a light safety shoe.
Safety shoes are known from the state of the art, which are capable of providing the user with a desired degree of protection in case of accidental events.
As is known, professional work shoes are to comply with stringent standards, included among which are:
In particular, in order to be defined as safety or accident-prevention shoes, the work shoes must be provided with a safety toecap and therefore comply with standards EN ISO 20344, EN ISO 20345 and EN ISO 20346.
Safety shoes therefore comprise an upper assembly provided, at the shoe toe, with a safety toecap which is sufficiently structured, and therefore rigid, to resist knocks or crushing, thus protecting the user's foot.
Furthermore, the safety shoes generally also comprise an anti-puncture sheet, placed below the insole, which protects the sole of the foot from sharp or pointed objects that the user might step on.
In general, since work footwear is involved, it is intended to be worn by the user continuously for several hours a day.
Currently, however, the safety shoes of known type have a significant weight, which, for a single European size 42 shoe, is generally more than 550 grams.
Such weight is determined first and foremost by the fact that the materials from which the various parts of the shoes are made must ensure particular resistance to the shoe itself, in order to ensure lasting use. In fact, whether related to the sole or upper, the materials must be resistant to abrasion, to damage that may occur from blows or from sharp or pointed objects, to damage from contact with corrosive chemicals.
Furthermore, the need to provide, and integrate into the shoe, the safety toecap and the anti-puncture sheet means a further increase in the weight of the shoe. In fact, if they also comprise a steel anti-puncture sheet, some well-known safety shoes have an average weight, for a single European size 42 shoe, of up to 600 grams.
In order to ensure adequate durability in the working environments where safety shoes are used, the soles of safety shoes are generally manufactured by means of injection moulding techniques directly onto the upper. In fact, it is well known that the alternative to moulding the sole onto the upper, consisting of bonding the upper to the sole, does not allow for equally durable and high-performance safety shoes, and is in fact scarcely adopted.
It is also evident that the heavier the shoes, the less comfortable they are for the user, particularly in view of the fact that safety shoes are worn continuously for many hours a day and that the users are often engaged in activities that require frequent movement.
The main task of the present invention is to create a safety shoe that is significantly lighter than the known safety shoes, even if provided with an anti-puncture sheet, and that is capable of ensuring not only a high level of comfort for the user, but also a high level of durability and longevity.
Within the scope of this task, it is an object of the present invention to make a light safety shoe that meets the requirements of any type of user.
The task disclosed above, and also the objects mentioned and others which are more apparent below, are achieved by a light safety shoe as illustrated in claim 1.
Other features are comprised in the dependent claims.
Further features and advantages shall be more apparent from the description of a preferred, but not exclusive, embodiment of light a safety shoe, illustrated by mere way of non-limiting example with the aid of the accompanying drawings, in which:
With reference to the above figures, the light safety shoe, indicated globally by reference number 1, comprises:
According to the invention:
According to the invention, the light safety shoe 1 has, with reference to a European size 42, a weight lower or equal to 400 grams.
Preferably, the polyester-based polyurethane with which the sole 3 is made has a density, measured according to measurement standard UNI EN ISO 8451, lower than 430 Kg/m3, preferably between 400 and 450 Kg/m3, for example substantially equal to about 420 kg/m3.
The sole 3 can be made of a polyester-based polyurethane having a Shore hardness between 37 and 48 Shore A inclusive, preferably between 40 and 45 inclusive, and even more preferably between 41 and 43 inclusive. For example, in a preferred embodiment of the shoe 1, the polyester-based polyurethane has a hardness of 42 Shore A measured according to DIN 53505. Alternatively, according to ASKER standards, the polyester-based polyurethane used to make the sole 3 has a hardness preferably between 50 and 60 Asker C. For example, the polyester-based polyurethane has a hardness of 55 Asker C, which corresponds to 42 Shore A hardness measured according to DIN 53505.
The sole 3 can be made of a polyester-based polyurethane having a rebound between 38% and 43%, preferably greater than or equal to 40%, e.g., equal to about 40.5%.
The aforesaid resilience values of the materials with which the sole 3 is made are measured according to measurement standard DIN 53512 (“Determining the rebound resilience of rubber using the Schob pendulum”) and depict the ratio between the rebound energy by an elastomer subjected to a bump and the energy applied to such elastomer during the bump itself.
The functional insert 7 can be made of an expanded polyethylene-based compound having a Shore hardness, measured according to DIN 53505, between 21 and 34 Shore A inclusive, preferably between 23 and 29 Shore A, e.g., equal to 26 Shore A.
Preferably, the expanded polyethylene with which the functional insert 7 is made is a closed-cell expanded polyethylene that is chemically cross-linked.
Preferably, such material has an elongation at longitudinal break, measured according to DIN 53571, greater than 85%, preferably greater than 90%, and an elongation at transverse break greater than 95%, preferably greater than 100%.
Preferably, such material has a density, measured according to standard DIN 53420, lower than 60 kg/m3, more preferably between 45 and 55 kg/m3.
Preferably, the functional insert 7 extends at the rear area of the light safety shoe 1 on a surface greater than 45% of the total surface of the sole 3, preferably on a surface substantially between 45% and 60% of the total surface of the sole 3, and preferably between 53% and 57%, and even more preferably around 55%. Always preferably, the functional insert 7, with reference to a European size 42, has a length between 60 mm and 80 mm and a width between 40 mm and 60 mm. For example, with reference to a European size 42, the functional insert 7 has a length of 70 mm and a width of 50 mm.
Preferably the functional insert 7 has a thickness greater than 10 millimetres, with reference to a European reference size 42, preferably between 12 and 18 millimetres. For example, with reference to a European size 42, the functional insert 7 is 15 millimetres thick. Thereby, the sole 3 is significantly lighter overall thanks to the presence of such a functional insert 7.
Furthermore, the aforesaid dimensions of the functional insert 7 allow to provide an adequate support surface for the heel of the user's foot during the user's activities in the working day.
Preferably, the anti-puncture sheet 9 is in direct contact with the upper face of the functional insert 7.
The anti-puncture sheet 9 can be made of non-woven fabric comprising high-density polyethylene fibres, synthetic resins, and steel fibres. Preferably such a non-woven fabric comprises high-density polyethylene fibres in a range between 75% and 89% by weight, synthetic resins in a range between 5 and 15% by weight and steel fibres in a range between 4% and 12% by weight. For example, in a preferred embodiment of the shoe 1, the anti-puncture sheet 9 comprises 82% high-density polyethylene fibres, 10% synthetic resins and 8% steel fibres.
Always preferably, the anti-puncture sheet 9 has a mass per unit area, calculated according to standard UNI EN ISO 2286-2, between 1800 and 2200 g/m2, e.g., equal to 2000 g/m2.
Preferably, the high-density polyethylene fibres are of the recycled type.
The anti-puncture sheet 9 can have a thickness between 3.0 mm and 4.0 mm, preferably substantially equal to 3.5 mm.
Preferably, the non-woven fabric of the upper 2 comprises cotton, polyethylene terephthalate (PET), polyurethane and polyester fibre.
Depending on the shoe model, non-woven fabric types in which the above-mentioned materials are combined in various percentages can be used for the upper 2.
For example, the non-woven fabric of the upper 2 can comprise, by weight, at least 40% cotton, at least 20% PET and at least 15% polyurethane.
The upper 2 preferably has a mass per unit area, measured according to standard EN ISO 3801, between 900 and 700 g/m2, e.g., equal to about 790 g/m2.
The sole 3 can comprise, on at least one side face, and preferably on both side faces, a plurality of lightening hollows 30 configured to lighten the overall weight of the sole 3.
Such lightening hollows 30 are preferably greater than or equal to three in number and are mutually adjacent to each other.
Such lightening hollows 30 are mutually separated by walls 31, or ribs, which also confer a cushioning and energy return function during walking to the sole 3.
Preferably, the lightening hollows 30 are arranged in the rear area of shoe 1, at the heel of shoe 1.
Preferably the sole 3 is completely and exclusively made of said polyester-based polyurethane by injection moulding directly onto the upper 2.
In other words, the sole 3, comprising both the tread 5, i.e., the portion of the sole itself 3 apt, in use, to be in contact with the ground, and the portion 6 in which the functional insert 7 and the anti-puncture sheet 9 are housed, is made in one piece, mono-material, by means of injection moulding techniques in a single mould, directly on the upper 2.
In accordance, the material in which the sole 3 is made is also configured to meet the mechanical requirements usually required to make the tread 5.
Preferably, the material from which the sole 3 is made has an abrasion resistance, measured according to standard ISO 4649, which provides for measuring the volume of material lost as a result of rubbing tests, lower than 100 mm3, preferably lower than 85 mm3, e.g., equal to about 83 mm3.
Preferably, the polyester-based polyurethane in which the sole 3 is made has a tensile strength, measured according to measurement standard DIN 53504, between 4 and 7 MPa, preferably between 5 and 6 MPa, e.g., substantially equal to 5.5 MPa.
Preferably, the polyester-based polyurethane in which sole 3 is made has an elongation at break, measured according to measurement standard DIN 53504 between 350 and 450%, preferably around 400%.
Preferably, such a polyester-based polyurethane is obtained from a mixture of polyester polyols and a diphenylmethane diisocyanate, which is preferably 4,4′-diphenylmethanediisocyanate.
For example, the weight ratio of polyols to isocyanate is between 100:(105-120). More preferably, the weight ratio between polyols and isocyanate is 100:112.
An amine catalyst is also provided, which is preferably an aliphatic amine, more preferably a tertiary amine, and/or a glycol.
As mentioned, the presence of the safety toecap 4 allows the shoe 1 to meet the current safety standards, and in particular standards UNI EN ISO 20344 and UNI EN ISO 20345, or also Standard UNI EN ISO 20346.
The safety toecap 4 is preferably made of aluminium.
In practice, the light safety shoe, according to the present invention, fulfils the task as well as the intended objects in that it weighs at least 20% less with respect to a corresponding safety shoe of a known type, and is comfortable to wear and use.
Another advantage of the safety shoe, according to the invention, is that it is relatively simple to manufacture, as the sole is made in one piece and moulded directly onto the upper.
The light 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 equivalent technical elements. In practice, the materials used, as well as their 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.
| Number | Date | Country | Kind |
|---|---|---|---|
| 102022000001307 | Jan 2022 | IT | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/IB2023/050430 | 1/18/2023 | WO |
