A shoe sole with improved puncture resistance and a safety shoe

Abstract

The shoe sole comprises a heel area (11) and a ball area (12), an outsole (16) configured to come into contact with the ground, a midsole (15) extending over the outsole, an elastic insert (18) embedded into the midsole in the heel area of the shoe sole and a first anti-puncture sheet (22) extending over the midsole in the heel area and the ball area, the first anti-puncture sheet being substantially flexible. The shoe sole further comprises a second anti puncture sheet (32) locating between the outsole and the elastic insert and extending exclusively over the heel area of the shoe sole, the second anti-puncture sheet being substantially rigid.

Description

Technical Field

[0001] The invention is related to a shoe sole comprising a heel area and a ball area, an outsole configured to come into contact with the ground, a midsole extending over the outsole, an elastic insert embedded into the midsole in the heel area of the shoe sole and a first anti-puncture sheet extending over the midsole in the heel area and the ball area, the first anti-puncture sheet being substantially flexible. The invention is further related to a safety shoe comprising said shoe sole.Background Art

[0002] Safety shoes, or anti-injury shoes, offer their users a high degree of protection against puncture wounds and crushing injuries. All safety shoes, in order to respect the current standards of the field, comprise an upper provided with a sufficiently rigid protective toe cap to withstand impacts, protecting the user's toes from crushing. Further, the safety shoes are provided with puncture resistant sheet, which prevents sharp objects, such as nails, to penetrate through the shoe sole. Safety shoes are usually used as working shoes, whereby they are intended to be worn by the user for many hours per day in activities, in which the user is in continuous movement. Therefore, the safety shoes must be to be able to ensure a satisfactory level of comfort for the user. For this purpose, many safety shoes are equipped with a layered sole comprising an insert made of elastic material. The elastic insert makes it more comfortable to stand on the floor and it provides a soft and dynamic shock absorption during walking. Although such anti-injury shoes have been successful with users and are currently very common, they are not without drawbacks.

[0003] Document EP 3648628 B1 discloses a safety shoe, comprising a layered sole having an upper layer, an intermediate layer and a lower layer adapted to come into contact with the ground. In the intermediate layer an elastic insert is embedded, which extends exclusively at the rear zone of said sole. The upper layer comprises an anti-puncture sheet thoroughly covering the sole and overlapping the elastic insert. The anti-puncture sheet is preferably made of non-metallic, flexible material. Document US 2022007783 A1 discloses an outsole for a safety footwear comprising a top surface designed to support the foot of the wearer, a bottom surface designed to be in contact with the ground and a flexible anti-perforation layer between the top and bottom surface. The anti-perforation layer has a surface area for protection the whole bottom part of the foot of the wearer from punctures.

[0004] Soft and flexible anti-puncture sheets alone do not provide maximum protection against punctures, whereby protection of the user's feet is compromised.

[0005] Document KR 20070117233 A discloses a shoe, comprising a layered sole. In the heel area of the sole a shock absorbing member including coil springs is embedded. The midsole comprises a rigid protective plate thoroughly covering the sole and overlapping the shock absorbing member. Document WO 2021124068 A1 discloses an anti-perforation sole for footwear comprising a midsole provided with a shock-absorbing insert and a rigid puncture resistant sheet extending from the front end of the sole to the rear end of the sole. Document FR 2583269 A1 discloses a safety shoe comprising an anti-nail sole and a shock absorber pad housed in the heel. The anti-nail sole includes a metal plate covering both the heel area and the ball area of the sole.

[0006] Single metal plates covering the whole area of the sole make the sole rigid and uncomfortable to use.

[0007] An object of the invention is to provide shoe sole and a safety shoe, in which drawbacks relating to the prior art are reduced.

[0008] The object of the invention is achieved with a shoe sole and a safety shoe, which are characterized in what is disclosed in the independent patent claims. Some preferred embodiments of the invention are disclosed in the dependent claims.Summary of the invention

[0009] The shoe sole according to the invention comprises a heel area and a ball area, an outsole configured to come into contact with the ground, a midsole extending over the outsole, an elastic insert embedded into the midsole in the heel area of the shoe sole and a first anti-puncture sheet extending over the midsole in the heel area and the ball area the first anti-puncture sheet being substantially flexible. The shoe sole further comprises a second anti puncture sheet locating between the outsole and the elastic insert and extending over the heel area of the shoe sole, the second anti-puncture sheet being substantially rigid.

[0010] In some embodiments of the shoe sole according to the invention the first anti-puncture sheet comprises at least one textile layer having a tight weave of threads. Preferably the first anti-puncture sheet is a layered structure comprising several superimposed tight weaved textile layers.

[0011] In some embodiments of the shoe sole according to the invention the shoe sole has a first end in the ball area, and a second end in the heel area and the first anti-puncture sheet extends from the first end of the shoe sole to the second end of the shoe sole.

[0012] In some embodiments of the shoe sole according to the invention the first anti-puncture sheet has a hole in the heel area of the shoe sole, the hole exposing a major part of the surface of the elastic insert facing the first anti-puncture sheet.

[0013] Some embodiments of the shoe sole according to the invention further comprise an insole substantially covering the first anti-puncture sheet and the first anti-puncture sheet is attached or integrated into to the insole.

[0014] In some embodiments of the shoe sole according to the invention said second anti-puncture sheet is a shaped metal plate, preferably a shaped steel plate.

[0015] In some embodiments of the shoe sole according to the invention the second anti-puncture sheet has a first edge portion bending towards the first anti-puncture sheet, which first edge portion is closer to the first end of the shoe sole than the second end. Preferably the first edge portion extends close to or in contact to the first anti-puncture sheet. The first edge portion acts as a guiding plate steering the tip of a sharp rod-like object to slantly towards the first anti-puncture, when the rod-like object protrudes into the heel area of the shoe sole.

[0016] In some embodiments of the shoe sole according to the invention the second anti-puncture sheet has a second edge portion bending towards the first anti-puncture sheet, which second edge portion is closer to the second end of the shoe sole that the first end. The second edge portion acts as a guiding plate steering the tip of a sharp rod-like object to pass the heel of the user's feet, when the rod-like object protrudes into heel area of the shoe sole.

[0017] In some embodiments of the shoe sole according to the invention the second anti-puncture sheet has a perimeter and the hole of the first anti-puncture sheet has a circumference, which is locating within said perimeter, when seen from the direction perpendicular to second anti-puncture sheet.

[0018] In some embodiments of the shoe sole according to the invention the second anti-puncture sheet is attached to the elastic insert, preferably by gluing.

[0019] In some embodiments of the shoe sole according to the invention the midsole is attached to the first anti-puncture sheet and to the second anti-puncture sheet. Preferably, the midsole comprises polyurethane material attaching the midsole to the first and second anti-puncture sheets.

[0020] In some embodiments of the shoe sole according to the invention the second anti-puncture sheet has an upper surface and a lower surface, which are covered with a primer for enhancing the attachment of the midsole to the second anti-puncture sheet.

[0021] A safety shoe according to the invention comprises an embodiment of a shoe sole explained above and an upper attached to the shoe sole. Preferably, the upper comprises a protective cap covering the tip of the ball area of the shoe sole.

[0022] An advantage of the invention is, that the softness of the shoe sole and comfort of use of the shoe is good without compromising the puncture resistance of the shoe sole.

[0023] Another advantage of the invention is, that the elastic insert is protected against penetrating of puncturing sharp objects, which ensures, that the integrity and elastic properties of the insert are not weakened.Brief Description of the Drawings

[0024] In the following the invention will be described in detail, by way of examples, with reference to the accompanying drawings in which, Fig. 1adepicts an example of an exploded safety shoe according to the invention as a side elevation view, Fig. 1bdepicts an example of a shoe sole according to the invention seen from above and Fig. 2depicts the safety shoe of figure 1 as an overall side elevation view. Detailed Description

[0025] In figure 1a an example of a safety shoe according to the invention is shown as an exploded side elevation view. The safety shoe according to the invention comprises an upper 50 and a layered shoe sole 10 attached to the upper. The upper is equipped with a protective cap 52 satisfying the current safety standards for protecting the user's toes from crushing, when an impact or a pressing force effects on the shoe tip. The shoe sole has a heel area 11 for supporting the heel of the user and a ball area 12 for supporting the forefoot, i.e. the ball and toes of the user when the shoe is worn.

[0026] The layered shoe sole 10 comprises a first anti-puncture sheet 22 configured to face the wearers sole, an outsole 16 configured to come into contact with the ground and a midsole 15 between the first anti-puncture sheet and the outsole. The first anti-puncture sheet extends over the ball area 12 of the shoe sole and the heel area 11 of the shoe sole i.e. it covers substantially the whole area of the shoe sole. The first anti-puncture sheet 22 is a flexible textile layer having an extremely tight weave of threads in combination with nonwoven materials.

[0027] The first anti-puncture sheet is configured to face the wearer's feet, when the shoe is worn. On the upper side of the first anti-puncture sheet, i.e. on the side facing the wearer's feet, there may be a separate insole 14, which is made of heavy paper or thick non-woven fabric or the first anti-puncture sheet and the insole 14 may be integrated into a single element.

[0028] The outsole 16 is preferably made of rubber or other similar material. The outer surface of the outsole, which is configured to come into contact with the ground, has an uneven surface shaping for providing sufficient friction between the outsole and the ground.

[0029] The midsole 15 is made of injection molded polyurethane. An elastic insert 18 is embedded into the midsole exclusively in the heel area of the sole during manufacturing phase of the midsole. The elastic insert is a flexible and compressible element which is at least partly, preferably fully, made of foamed thermoplastic polyurethane. The elastic insert is significantly softer material that the midsole although they are both made of polyurethane. The elastic insert extends exclusively to the heel area of the shoe sole covering 30-50 %, preferably 35-40 % of the overall length of the shoe sole 10. The width of the elastic insert is substantially equal to or slightly less than the width the midsole in the heel area 11 of the shoe sole. The thickness of the elastic insert is between 15-25 mm, preferably substantially 20 mm.

[0030] The midsole 15 comprises a window 20 on both side surfaces of the midsole in the heel area of the shoe sole. The elastic insert is partly visible through these windows. The windows allow the elastic insert to slightly protrude outward through the windows assisting the deformation of the elastic insert material during compression.

[0031] aThis increased deforming capacity enhances the ability to elastically absorb the forces deriving from the weight of the user during walking. The size and shape of the window is smaller than the side surface of the elastic insert facing the window, whereby only a part of the elastic insert is visible through the windows. Apart from the area of the windows the midsole surrounds the sides of the elastic insert.

[0032] The shoe sole further comprises a second anti-puncture sheet 32, which extends exclusively inside the heel area 11 of the shoe sole 10 near to the outer edges of the shoe sole for protecting especially the user's heel against protruding sharp objects, such as nails, when the shoe is worn. The second anti-puncture sheet has an upper surface facing the first anti puncture sheet 22 and a lower surface facing the outsole 16 and it is made of steel sheet having a thickness 0,6-1,0 mm, preferably 0,8 mm. The second anti-puncture sheet is shaped from a single metal sheet and it has a first edge portion 34 closer to the first end 30 of the shoe sole 10 and second edge portion 36 is closer to the second end 31 of the shoe sole (fig. 2). The first edge portion may bend towards the first anti-puncture sheet 22 and it may extend close to or in contact to the first anti-puncture sheet. The height of the first edge portion may be substantially equal to the thickness of the elastic insert 18. The purpose of the bending of the first edge portion is to steer the tip of a protruding object to slantly towards the first anti-puncture i.e. to prevent the sharp object entering into the gap between the first and second anti puncture sheets when the object protrudes into the front heel area of the shoe sole. Similarly, the second edge portion 36 may bend slantly upwards towards the first anti-puncture sheet 22 for steering the tip of a sharp protruding object to pass the heel of the user's feet, when the object protrudes into rear heel area of the shoe sole.

[0033] The upper and the lower surfaces of the second anti-puncture sheet are covered with a primer for enhancing the attachment between the midsole and the second anti-puncture sheet. Preferably the primer has conductive properties, which help the shoe to satisfy the antistatic requirements stated in the safety shoe standards.

[0034] In figure 1b an example of a shoe sole according to the invention is show from above.

[0035] In the heel area of the first anti-puncture sheet 22 there is hole 28 exposing the elastic insert 18 below the first anti-puncture sheet. The lateral dimensions of the elastic insert are slightly larger than the lateral dimensions of the hole 28. The first anti-puncture sheet provides protection for the user's feet sole against protruding sharp objects over the whole area of the shole sole, except within the circumference 29 of the hole. The lateral dimensions of the second anti-puncture sheet 32 locating below the elastic insert 18 and providing puncture protection for the heel of the shoe's wearer, are even larger that the lateral dimensions of the elastic insert. The perimeter 38 of the second anti-puncture sheet 32 is clearly bigger than the circumference 29 of the hole 28 and the circumference is locating within said perimeter, when seen from the direction perpendicular to second anti-puncture sheet. Thus, around the hole there is an annular region, where the first and second anti-puncture sheets overlap to ensure, that sharp objects cannot not pass the second anti-puncture sheet and protrude through the hole 28 in the first anti-puncture sheet even if the sharp objects were in slightly inclined position.

[0036] In figure 2 the safety shoe of figure 1 is shown as a side elevation view. The first anti-puncture sheet 22 is attached to the midsole 15 and the second anti-puncture sheet 32 is attached to the lower surface of the elastic 18 insert by gluing. The midsole 15 is attached directly to the lower surface of the first anti-puncture sheet both in the heel area and in the ball area. The midsole attaches also to the upper 50 with a protective cap 52 and the outsole 16. The midsole also surrounds the sides of the elastic insert 18 apart from the area of the windows in the side surfaces of the heel area of the shoe sole (fig. 1). The midsole is made of polyurethane material by injection moulding, whereby the midsole attaches to the elastic insert, first and second anti-puncture sheets and to the outsole through the adhesive force of the polyurethane material.

[0037] When safety shoes are used, a major part of the weight of the user exerts to the heel area of the shoe sole, especially during walking. In the safety shoe according to the invention the second anti-puncture sheet 32 is locating precisely in the heel area between the outsole 16 and the elastic insert 18 providing maximum puncture protection for the heel of the shoe's wearer. Between the outsole and the second anti-puncture sheet there is a layer of midsole material, i.e. polyurethane. Thus, in the heel area of the shoe sole 10 there is a cushioning elastic insert 18 between the second anti-puncture sheet 32 and the upper surface of the shoe sole facing the user's feet. Therefore, in the heel area, the substantially rigid second anti-puncture sheet does not deteriorate the cushioning effect of the elastic insert. Further, in the first anti-puncture sheet there is a hole 28 in the heel area of the shoe sole, which hole exposes a major part of the upper surface of the elastic insert facing the user's feet. Thus, in the area of the hole the upper surface of the elastic insert constitutes the uppermost surface of the shoe sole, whereby forces and impacts exerting through the heels of the user affect directly to the elastic insert providing maximum cushioning effect.

[0038] The shoe sole must be flexible enough in the longer direction sole to facilitate comfort walking with the shoe. The metallic second anti-puncture sheet 32 makes the shoe sole stiffer, but only in the heel area. In the shoe sole according to the invention the flexible first anti-puncture sheet 22 extends over the whole ball area of the sole and over the area surrounding the hole 28 in the heel area. Thus, in the shoe sole according to the invention the whole sole area is covered either by the first anti-puncture sheet or by the second anti-puncture sheet or both. The flexible first anti-puncture allows the shoe sole to bend and curve during walking thus making the wearing of the shoe more comfort.

[0039] Some preferred embodiments of shoe sole and the safety shoe has been disclosed above. The invention is not limited to the solutions explained above, but the invention can be applied in different ways within the limits set by the patent claims.Reference Signs:

[0040] 10shoe sole 11heel area 12ball area 14insole 15midsole 16outsole 18elastic insert 20window 22first anti-puncture sheet 28hole 29circumference 30first end 31second end 32second anti-puncture sheet 34first edge portion 36second edge portion 38perimeter 50upper 52protective cap

Examples

Embodiment Construction

[0025]In figure 1a an example of a safety shoe according to the invention is shown as an exploded side elevation view. The safety shoe according to the invention comprises an upper 50 and a layered shoe sole 10 attached to the upper. The upper is equipped with a protective cap 52 satisfying the current safety standards for protecting the user's toes from crushing, when an impact or a pressing force effects on the shoe tip. The shoe sole has a heel area 11 for supporting the heel of the user and a ball area 12 for supporting the forefoot, i.e. the ball and toes of the user when the shoe is worn.

[0026]The layered shoe sole 10 comprises a first anti-puncture sheet 22 configured to face the wearers sole, an outsole 16 configured to come into contact with the ground and a midsole 15 between the first anti-puncture sheet and the outsole. The first anti-puncture sheet extends over the ball area 12 of the shoe sole and the heel area 11 of the shoe sole i.e. it covers substantially the whole...

Technical Field

[0001] The invention is related to a shoe sole comprising a heel area and a ball area, an outsole configured to come into contact with the ground, a midsole extending over the outsole, an elastic insert embedded into the midsole in the heel area of the shoe sole and a first anti-puncture sheet extending over the midsole in the heel area and the ball area, the first anti-puncture sheet being substantially flexible. The invention is further related to a safety shoe comprising said shoe sole.Background Art

[0002] Safety shoes, or anti-injury shoes, offer their users a high degree of protection against puncture wounds and crushing injuries. All safety shoes, in order to respect the current standards of the field, comprise an upper provided with a sufficiently rigid protective toe cap to withstand impacts, protecting the user's toes from crushing. Further, the safety shoes are provided with puncture resistant sheet, which prevents sharp objects, such as nails, to penetrate through the shoe sole. Safety shoes are usually used as working shoes, whereby they are intended to be worn by the user for many hours per day in activities, in which the user is in continuous movement. Therefore, the safety shoes must be to be able to ensure a satisfactory level of comfort for the user. For this purpose, many safety shoes are equipped with a layered sole comprising an insert made of elastic material. The elastic insert makes it more comfortable to stand on the floor and it provides a soft and dynamic shock absorption during walking. Although such anti-injury shoes have been successful with users and are currently very common, they are not without drawbacks.

[0003] Document EP 3648628 B1 discloses a safety shoe, comprising a layered sole having an upper layer, an intermediate layer and a lower layer adapted to come into contact with the ground. In the intermediate layer an elastic insert is embedded, which extends exclusively at the rear zone of said sole. The upper layer comprises an anti-puncture sheet thoroughly covering the sole and overlapping the elastic insert. The anti-puncture sheet is preferably made of non-metallic, flexible material. Document US 2022007783 A1 discloses an outsole for a safety footwear comprising a top surface designed to support the foot of the wearer, a bottom surface designed to be in contact with the ground and a flexible anti-perforation layer between the top and bottom surface. The anti-perforation layer has a surface area for protection the whole bottom part of the foot of the wearer from punctures.

[0004] Soft and flexible anti-puncture sheets alone do not provide maximum protection against punctures, whereby protection of the user's feet is compromised.

[0005] Document KR 20070117233 A discloses a shoe, comprising a layered sole. In the heel area of the sole a shock absorbing member including coil springs is embedded. The midsole comprises a rigid protective plate thoroughly covering the sole and overlapping the shock absorbing member. Document WO 2021124068 A1 discloses an anti-perforation sole for footwear comprising a midsole provided with a shock-absorbing insert and a rigid puncture resistant sheet extending from the front end of the sole to the rear end of the sole. Document FR 2583269 A1 discloses a safety shoe comprising an anti-nail sole and a shock absorber pad housed in the heel. The anti-nail sole includes a metal plate covering both the heel area and the ball area of the sole.

[0006] Single metal plates covering the whole area of the sole make the sole rigid and uncomfortable to use.

[0007] An object of the invention is to provide shoe sole and a safety shoe, in which drawbacks relating to the prior art are reduced.

[0008] The object of the invention is achieved with a shoe sole and a safety shoe, which are characterized in what is disclosed in the independent patent claims. Some preferred embodiments of the invention are disclosed in the dependent claims.Summary of the invention

[0009] The shoe sole according to the invention comprises a heel area and a ball area, an outsole configured to come into contact with the ground, a midsole extending over the outsole, an elastic insert embedded into the midsole in the heel area of the shoe sole and a first anti-puncture sheet extending over the midsole in the heel area and the ball area the first anti-puncture sheet being substantially flexible. The shoe sole further comprises a second anti puncture sheet locating between the outsole and the elastic insert and extending over the heel area of the shoe sole, the second anti-puncture sheet being substantially rigid.

[0010] In some embodiments of the shoe sole according to the invention the first anti-puncture sheet comprises at least one textile layer having a tight weave of threads. Preferably the first anti-puncture sheet is a layered structure comprising several superimposed tight weaved textile layers.

[0011] In some embodiments of the shoe sole according to the invention the shoe sole has a first end in the ball area, and a second end in the heel area and the first anti-puncture sheet extends from the first end of the shoe sole to the second end of the shoe sole.

[0012] In some embodiments of the shoe sole according to the invention the first anti-puncture sheet has a hole in the heel area of the shoe sole, the hole exposing a major part of the surface of the elastic insert facing the first anti-puncture sheet.

[0013] Some embodiments of the shoe sole according to the invention further comprise an insole substantially covering the first anti-puncture sheet and the first anti-puncture sheet is attached or integrated into to the insole.

[0014] In some embodiments of the shoe sole according to the invention said second anti-puncture sheet is a shaped metal plate, preferably a shaped steel plate.

[0015] In some embodiments of the shoe sole according to the invention the second anti-puncture sheet has a first edge portion bending towards the first anti-puncture sheet, which first edge portion is closer to the first end of the shoe sole than the second end. Preferably the first edge portion extends close to or in contact to the first anti-puncture sheet. The first edge portion acts as a guiding plate steering the tip of a sharp rod-like object to slantly towards the first anti-puncture, when the rod-like object protrudes into the heel area of the shoe sole.

[0016] In some embodiments of the shoe sole according to the invention the second anti-puncture sheet has a second edge portion bending towards the first anti-puncture sheet, which second edge portion is closer to the second end of the shoe sole that the first end. The second edge portion acts as a guiding plate steering the tip of a sharp rod-like object to pass the heel of the user's feet, when the rod-like object protrudes into heel area of the shoe sole.

[0017] In some embodiments of the shoe sole according to the invention the second anti-puncture sheet has a perimeter and the hole of the first anti-puncture sheet has a circumference, which is locating within said perimeter, when seen from the direction perpendicular to second anti-puncture sheet.

[0018] In some embodiments of the shoe sole according to the invention the second anti-puncture sheet is attached to the elastic insert, preferably by gluing.

[0019] In some embodiments of the shoe sole according to the invention the midsole is attached to the first anti-puncture sheet and to the second anti-puncture sheet. Preferably, the midsole comprises polyurethane material attaching the midsole to the first and second anti-puncture sheets.

[0020] In some embodiments of the shoe sole according to the invention the second anti-puncture sheet has an upper surface and a lower surface, which are covered with a primer for enhancing the attachment of the midsole to the second anti-puncture sheet.

[0021] A safety shoe according to the invention comprises an embodiment of a shoe sole explained above and an upper attached to the shoe sole. Preferably, the upper comprises a protective cap covering the tip of the ball area of the shoe sole.

[0022] An advantage of the invention is, that the softness of the shoe sole and comfort of use of the shoe is good without compromising the puncture resistance of the shoe sole.

[0023] Another advantage of the invention is, that the elastic insert is protected against penetrating of puncturing sharp objects, which ensures, that the integrity and elastic properties of the insert are not weakened.Brief Description of the Drawings

[0024] In the following the invention will be described in detail, by way of examples, with reference to the accompanying drawings in which, Fig. 1adepicts an example of an exploded safety shoe according to the invention as a side elevation view, Fig. 1bdepicts an example of a shoe sole according to the invention seen from above and Fig. 2depicts the safety shoe of figure 1 as an overall side elevation view. Detailed Description

[0025] In figure 1a an example of a safety shoe according to the invention is shown as an exploded side elevation view. The safety shoe according to the invention comprises an upper 50 and a layered shoe sole 10 attached to the upper. The upper is equipped with a protective cap 52 satisfying the current safety standards for protecting the user's toes from crushing, when an impact or a pressing force effects on the shoe tip. The shoe sole has a heel area 11 for supporting the heel of the user and a ball area 12 for supporting the forefoot, i.e. the ball and toes of the user when the shoe is worn.

[0026] The layered shoe sole 10 comprises a first anti-puncture sheet 22 configured to face the wearers sole, an outsole 16 configured to come into contact with the ground and a midsole 15 between the first anti-puncture sheet and the outsole. The first anti-puncture sheet extends over the ball area 12 of the shoe sole and the heel area 11 of the shoe sole i.e. it covers substantially the whole area of the shoe sole. The first anti-puncture sheet 22 is a flexible textile layer having an extremely tight weave of threads in combination with nonwoven materials.

[0027] The first anti-puncture sheet is configured to face the wearer's feet, when the shoe is worn. On the upper side of the first anti-puncture sheet, i.e. on the side facing the wearer's feet, there may be a separate insole 14, which is made of heavy paper or thick non-woven fabric or the first anti-puncture sheet and the insole 14 may be integrated into a single element.

[0028] The outsole 16 is preferably made of rubber or other similar material. The outer surface of the outsole, which is configured to come into contact with the ground, has an uneven surface shaping for providing sufficient friction between the outsole and the ground.

[0029] The midsole 15 is made of injection molded polyurethane. An elastic insert 18 is embedded into the midsole exclusively in the heel area of the sole during manufacturing phase of the midsole. The elastic insert is a flexible and compressible element which is at least partly, preferably fully, made of foamed thermoplastic polyurethane. The elastic insert is significantly softer material that the midsole although they are both made of polyurethane. The elastic insert extends exclusively to the heel area of the shoe sole covering 30-50 %, preferably 35-40 % of the overall length of the shoe sole 10. The width of the elastic insert is substantially equal to or slightly less than the width the midsole in the heel area 11 of the shoe sole. The thickness of the elastic insert is between 15-25 mm, preferably substantially 20 mm.

[0030] The midsole 15 comprises a window 20 on both side surfaces of the midsole in the heel area of the shoe sole. The elastic insert is partly visible through these windows. The windows allow the elastic insert to slightly protrude outward through the windows assisting the deformation of the elastic insert material during compression.

[0031] aThis increased deforming capacity enhances the ability to elastically absorb the forces deriving from the weight of the user during walking. The size and shape of the window is smaller than the side surface of the elastic insert facing the window, whereby only a part of the elastic insert is visible through the windows. Apart from the area of the windows the midsole surrounds the sides of the elastic insert.

[0032] The shoe sole further comprises a second anti-puncture sheet 32, which extends exclusively inside the heel area 11 of the shoe sole 10 near to the outer edges of the shoe sole for protecting especially the user's heel against protruding sharp objects, such as nails, when the shoe is worn. The second anti-puncture sheet has an upper surface facing the first anti puncture sheet 22 and a lower surface facing the outsole 16 and it is made of steel sheet having a thickness 0,6-1,0 mm, preferably 0,8 mm. The second anti-puncture sheet is shaped from a single metal sheet and it has a first edge portion 34 closer to the first end 30 of the shoe sole 10 and second edge portion 36 is closer to the second end 31 of the shoe sole (fig. 2). The first edge portion may bend towards the first anti-puncture sheet 22 and it may extend close to or in contact to the first anti-puncture sheet. The height of the first edge portion may be substantially equal to the thickness of the elastic insert 18. The purpose of the bending of the first edge portion is to steer the tip of a protruding object to slantly towards the first anti-puncture i.e. to prevent the sharp object entering into the gap between the first and second anti puncture sheets when the object protrudes into the front heel area of the shoe sole. Similarly, the second edge portion 36 may bend slantly upwards towards the first anti-puncture sheet 22 for steering the tip of a sharp protruding object to pass the heel of the user's feet, when the object protrudes into rear heel area of the shoe sole.

[0033] The upper and the lower surfaces of the second anti-puncture sheet are covered with a primer for enhancing the attachment between the midsole and the second anti-puncture sheet. Preferably the primer has conductive properties, which help the shoe to satisfy the antistatic requirements stated in the safety shoe standards.

[0034] In figure 1b an example of a shoe sole according to the invention is show from above.

[0035] In the heel area of the first anti-puncture sheet 22 there is hole 28 exposing the elastic insert 18 below the first anti-puncture sheet. The lateral dimensions of the elastic insert are slightly larger than the lateral dimensions of the hole 28. The first anti-puncture sheet provides protection for the user's feet sole against protruding sharp objects over the whole area of the shole sole, except within the circumference 29 of the hole. The lateral dimensions of the second anti-puncture sheet 32 locating below the elastic insert 18 and providing puncture protection for the heel of the shoe's wearer, are even larger that the lateral dimensions of the elastic insert. The perimeter 38 of the second anti-puncture sheet 32 is clearly bigger than the circumference 29 of the hole 28 and the circumference is locating within said perimeter, when seen from the direction perpendicular to second anti-puncture sheet. Thus, around the hole there is an annular region, where the first and second anti-puncture sheets overlap to ensure, that sharp objects cannot not pass the second anti-puncture sheet and protrude through the hole 28 in the first anti-puncture sheet even if the sharp objects were in slightly inclined position.

[0036] In figure 2 the safety shoe of figure 1 is shown as a side elevation view. The first anti-puncture sheet 22 is attached to the midsole 15 and the second anti-puncture sheet 32 is attached to the lower surface of the elastic 18 insert by gluing. The midsole 15 is attached directly to the lower surface of the first anti-puncture sheet both in the heel area and in the ball area. The midsole attaches also to the upper 50 with a protective cap 52 and the outsole 16. The midsole also surrounds the sides of the elastic insert 18 apart from the area of the windows in the side surfaces of the heel area of the shoe sole (fig. 1). The midsole is made of polyurethane material by injection moulding, whereby the midsole attaches to the elastic insert, first and second anti-puncture sheets and to the outsole through the adhesive force of the polyurethane material.

[0037] When safety shoes are used, a major part of the weight of the user exerts to the heel area of the shoe sole, especially during walking. In the safety shoe according to the invention the second anti-puncture sheet 32 is locating precisely in the heel area between the outsole 16 and the elastic insert 18 providing maximum puncture protection for the heel of the shoe's wearer. Between the outsole and the second anti-puncture sheet there is a layer of midsole material, i.e. polyurethane. Thus, in the heel area of the shoe sole 10 there is a cushioning elastic insert 18 between the second anti-puncture sheet 32 and the upper surface of the shoe sole facing the user's feet. Therefore, in the heel area, the substantially rigid second anti-puncture sheet does not deteriorate the cushioning effect of the elastic insert. Further, in the first anti-puncture sheet there is a hole 28 in the heel area of the shoe sole, which hole exposes a major part of the upper surface of the elastic insert facing the user's feet. Thus, in the area of the hole the upper surface of the elastic insert constitutes the uppermost surface of the shoe sole, whereby forces and impacts exerting through the heels of the user affect directly to the elastic insert providing maximum cushioning effect.

[0038] The shoe sole must be flexible enough in the longer direction sole to facilitate comfort walking with the shoe. The metallic second anti-puncture sheet 32 makes the shoe sole stiffer, but only in the heel area. In the shoe sole according to the invention the flexible first anti-puncture sheet 22 extends over the whole ball area of the sole and over the area surrounding the hole 28 in the heel area. Thus, in the shoe sole according to the invention the whole sole area is covered either by the first anti-puncture sheet or by the second anti-puncture sheet or both. The flexible first anti-puncture allows the shoe sole to bend and curve during walking thus making the wearing of the shoe more comfort.

[0039] Some preferred embodiments of shoe sole and the safety shoe has been disclosed above. The invention is not limited to the solutions explained above, but the invention can be applied in different ways within the limits set by the patent claims.Reference Signs:

[0040] 10shoe sole 11heel area 12ball area 14insole 15midsole 16outsole 18elastic insert 20window 22first anti-puncture sheet 28hole 29circumference 30first end 31second end 32second anti-puncture sheet 34first edge portion 36second edge portion 38perimeter 50upper 52protective cap

Examples

Embodiment Construction

[0025]In figure 1a an example of a safety shoe according to the invention is shown as an exploded side elevation view. The safety shoe according to the invention comprises an upper 50 and a layered shoe sole 10 attached to the upper. The upper is equipped with a protective cap 52 satisfying the current safety standards for protecting the user's toes from crushing, when an impact or a pressing force effects on the shoe tip. The shoe sole has a heel area 11 for supporting the heel of the user and a ball area 12 for supporting the forefoot, i.e. the ball and toes of the user when the shoe is worn.

[0026]The layered shoe sole 10 comprises a first anti-puncture sheet 22 configured to face the wearers sole, an outsole 16 configured to come into contact with the ground and a midsole 15 between the first anti-puncture sheet and the outsole. The first anti-puncture sheet extends over the ball area 12 of the shoe sole and the heel area 11 of the shoe sole i.e. it covers substantially the whole...

Claims

1. A shoe sole (10) comprising a heel area (11) and a ball area (12), an outsole (16) configured to come into contact with the ground, a midsole (15) extending over the outsole (16), an elastic insert (18) embedded into the midsole (15) in the heel area (11) of the shoe sole (10) and a first anti-puncture sheet (22) extending over the midsole (15) in the heel area (11) and the ball area (12), the first anti-puncture sheet (22) being substantially flexible, characterised in that the shoe sole further comprises a second anti puncture sheet (32) locating between the outsole (16) and the elastic insert (18) and extending over the heel area (11) of the shoe sole (10), the second anti-puncture sheet (32) being substantially rigid.

2. The shoe sole according to claim 1, characterised in that, the first anti-puncture sheet (22) comprises at least one textile layer having a tight weave of threads.

3. The shoe sole according to claim 1 or 2, characterised in that, the shoe sole (10) has a first end (30) in the ball area (12), and a second end (31) in the heel area (11) and the first anti-puncture sheet (22) extends from the first end (30) of the shoe sole (10) to the second end (31) of the shoe sole (10).

4. The shoe sole according to any of the claims 1 to 3, characterised in that, the first anti-puncture sheet (22) has a hole (28) in the heel area (11) of the shoe sole (10), the hole (28) exposing a major part of the surface of the elastic insert (18) facing the first anti-puncture sheet (22).

5. The shoe sole according to any of the claims 1 to 4, characterised in that, shoe sole further comprises an insole (14) substantially covering the first anti-puncture sheet (22) and the first anti-puncture sheet (22) is attached or integrated into to the insole (14).

6. The shoe sole according to any of the claims 1 to 5, characterised in that, said second anti-puncture sheet (32) is a shaped metal plate, preferably a shaped steel plate.

7. The shoe sole according to any of the claims 1 to 6, characterised in that the second anti-puncture sheet (32) has a first edge portion (34) bending towards the first anti-puncture sheet (22), which first edge portion (34) is closer to the first end (30) of the shoe sole (10) than the second end (31).

8. The shoe sole according to claim 7, characterised in that the first edge portion (34) extends close to or in contact to the first anti-puncture sheet (22).

9. The shoe sole according to any of the claims 1 to 8, characterised in that the second anti-puncture sheet (32) has a second edge portion (36) bending towards the first anti-puncture sheet (22), which second edge portion (36) is closer to the second end (31) of the shoe sole (10) that the first end (30).

10. The shoe sole according to any of the claims 4 to 9, characterised in that the second anti-puncture sheet (32) has a perimeter (38) and the hole (28) of the first anti-puncture sheet (22) has a circumference (29), which is locating within said perimeter (38), when seen from the direction perpendicular to second anti-puncture sheet (32).

11. The shoe sole according to any of the claims 1 to 10, characterised in that the second anti-puncture sheet (32) is attached to the elastic insert (18), preferably by gluing.

12. The shoe sole according to any of the claims 1 to 11, characterised in that the midsole (15) is attached to the first anti-puncture sheet (22) and to the second anti-puncture sheet (32).

13. The shoe sole according to any of the claims 1 to 12, characterised in that, the midsole (15) comprises polyurethane material attaching the midsole (15) to the first and second anti-puncture sheets (22, 32).

14. The shoe sole according to claim 12 or 13, characterised in that, the second anti-puncture sheet (32) has an upper surface and a lower surface, which are covered with a primer for enhancing the attachment of the midsole (15) to the second anti-puncture sheet (32).

15. A safety shoe comprising a shoe sole (10) according to any of the claims 1 to 14 and an upper (50) attached to the shoe sole (10).

16. A safety shoe according to claim 15, characterised in that the upper (50) comprises a protective cap (52) covering the tip of the ball area (12) of the shoe sole (10).

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