SOLE PART FOR A SHOE

Abstract

 Sole part (100,200) for a shoe (20), the sole part (100,200) having a longitudinal direction (L), a lateral direction (W) and a height direction (H), the sole part (100,200) being associated with an upright use orientation, the sole part (100,200) comprising a cushioning midsole (110,210);
an outsole (150,250), having a wear surface (151,251) arranged to rest on a horizontal surface (10) in said upright use orientation; and
a protective layer (130,230), arranged to prevent sharp objects from penetrating through the sole part (100,200) when stepped upon by a user of a shoe (20) comprising the sole part (100,200),
wherein the protective layer (130,230) is arranged between the midsole (110,210) and the outsole (150,250),
wherein the midsole (110,210) defines an overall upwards concave shape as viewed in said upright use orientation and in a vertical cross-section perpendicular to the lateral direction (W), and
wherein the protective layer (130,230) follows the upwards concave shape.

Description

[0001] The present invention relates to a sole part for a shoe. The invention also relates to a shoe incorporating such sole part and also an upper. In particular, the invention relates to a protective sole part for a protective shoe, and correspondingly to a protective shoe.

[0002] In many shoe applications, such as for work protective shoes, it is desirable to prevent sharp objects, such as nails, that a user wearing the shoe steps on, from penetrating the sole and into the user's foot from below. To solve this problem, it is commonplace to incorporate a a protective layer into the shoe. Such protective layer is typically arranged to prevent sharp objects from penetrating through the sole when stepped upon by a user of a shoe comprising the sole part.

[0003] Known solutions for soles with such protective layers suffer from decreased comfort for the user, since the protective layer typically is in the form of a relatively rigid layer covering more or less the entire sole to provide full-surface protection and for regulatory reasons.

[0004] Known such solutions also do not offer adequate protection for when the user steps down hard on a pointy object, such as a nail. Such objects can sometimes penetrate the sole despite the protective cover, merely because of the force used in the stepping down.

[0005] For shoes in general, high wearing comfort and shape stability during prolonged use is desirable.

[0006] The present invention solves one or more of the above described problems.

[0007] Hence, the invention relates to a sole part for a shoe, the sole part having a longitudinal direction, a lateral direction and a height direction, the sole part being associated with an upright use orientation, the sole part comprising

a cushioning midsole;

an outsole, having a wear surface arranged to rest on a horizontal surface in said upright use orientation; and

a protective layer, arranged to prevent sharp objects from penetrating through the sole part when stepped upon by a user of a shoe comprising the sole part,

wherein the protective layer is arranged between the midsole and the outsole,

wherein the midsole defines an overall upwards concave shape as viewed in said upright use orientation and in a vertical cross-section perpendicular to the lateral direction, and

wherein the protective layer follows the upwards concave shape.

[0008] In some embodiments, the sole part furthermore comprises another cushioning layer arranged to cover only the heel of the sole part, the cushioning layer being arranged between the outsole and the protective layer.

[0009] In some embodiments, the protective layer comprises ceramic fibres.

[0010] In some embodiments, the protective layer is arranged in a cavity of the mid-sole.

[0011] In some embodiments, the midsole is made from an expanded polymer material.

[0012] In some embodiments, the sole part further comprises a shank arranged between the mid-sole and the outsole.

[0013] In some embodiments, the shank has a shape that follows the upwards concave shape of the mid-sole.

[0014] In some embodiments, the shank is arranged between the protective layer and the outsole.

[0015] In some embodiments, the shank is stiff and resilient, and in particular stiffer than the protective layer.

[0016] In some embodiments, an engagement between the shank and the protective layer is such that the shank, when only considering the engagement per se, is movable in relation to the protective layer across at least part of its horizontal extension when the sole part is in its upright use orientation.

[0017] In some embodiments, the shank is movable in relation to the protective layer along at least 50% of a main longitudinal-lateral surface of the protective layer.

[0018] In some embodiments, the shank is or comprises a stiff and resilient insole arranged to, by spring action, mechanically store and release energy during a step performed by the user.

[0019] In some embodiments, the insole extends to a longitudinal extreme front end of the sole part, possibly apart from a distance of at the most 2 cm.

[0020] In some embodiments, the shank is fastened to the protective layer and/or the midsole along a periphery of the shank.

[0021] In some embodiments, the shank is fastened to the protective layer using an elastic glue.

[0022] In some embodiments, the shank is designed with a locally varying stiffness, such as due to a vary-ing vertical cross-section along its longitudinal direction, arranged to cause the shank to primarily bend at the toe joints of a wearing user when subjected to a bend-ing force by the user's foot.

[0023] In some embodiments, the protective layer is made from a tougher material than the outsole and/or
the protective layer is made from a tougher material than a hardened glue fastening the outsole to the rest of the sole part.

[0024] Furthermore, the invention relates to a shoe, in turn comprising

a sole part according to any preceding claim; and

an upper fastened to the sole part.

[0025] In some embodiments, the shoe is a protective shoe.

[0026] In some embodiments, the shoe comprises a protective toe cap.

[0027] In the following, the invention will be described in detail, with reference to exemplifying embodiments of the invention and to the enclosed drawings, wherein:

Figure 1 is a first perspective view of a first shoe, shown from above, the first shoe having an upper and a first sole part;

Figure 2 is a second perspective view of first sole part, shown from below;

Figure 3 is a cross-sectional third perspective view of the first sole part;

Figure 4 is an exploded cross-sectional fourth perspective view of the first sole part;

Figure 5 is an exploded fifth perspective view of the first sole part;

Figure 6 is a first perspective view of a second shoe, shown from above, the second shoe having an upper and a second sole part;

Figure 7 is a second perspective view of the second sole part, shown from below;

Figure 8 is a cross-sectional third perspective view of the second sole part;

Figure 9 is an exploded cross-sectional fourth perspective view of the second sole part;

Figure 10 is an exploded fifth perspective view of the second sole part; and

Figure 11 is an exploded cross-sectional sixth perspective view of the second sole part.

[0028] Hence, the drawings show two different embodiments of a first 100 and a second 200 shoe. Throughout the Figures, same two last digits of all reference numerals are used to denote same or corresponding parts. For three-digit reference numerals, the first digit signifies the embodiment (1 or 2).

[0029] The invention generally relates to a sole part 100, 200 for a shoe 20. The sole part 100, 200 is associated with a longitudinal direction L, running from heel to toe of the shoe 20; a lateral direction W, running sideways with respect to the shoe 20; and a height direction H, being vertical in an upright use orientation for the sole part 100, 200 wherein the sole part 100, 200 rests in an upright orientation on the horizontal ground 10. Hence, the upright use orientation is the normal orientation of the sole part 100, 200 when standing on the horizontal ground 10 for use by a user of a shoe 20 that the sole part 100, 200 forms part of.

[0030] As is indicated in Figures 1 and 6, the shoe 20 comprises the sole part 100, 200 as well as an upper 22 fastened to the sole part 100, 200. The upper 22 can be of any suitable type and made from any woven textile material, non-woven textile material, leather and/or any other suitable material. In some embodiments the shoe 20 is a protective shoe and the upper 22 is an upper suitable for use as part of such a protective shoe. In some embodiments, the shoe 20 comprises a protective toe cap 21, that can be made of metal or other suitable rigid materials, such as materials being or comprising metals, plastics, glass fiber, carbon fiber, and/or similar, and be arranged to prevent heavy objects falling down onto the upper 20 from damaging the foot of a user wearing the shoe 20.

[0031] As is illustrated in the Figures, the sole part 100, 200 comprises a cushioning midsole 110, 210. Part of, a majority of, or the entire cushioning midsole 110, 210 can be made from an expanded polymer material, such as a foamed thermoplastic polyurethane material; an ethylene-vinyl acetate material; an expanded polyethylene material; or combinations or mixtures of such and/or other materials.

[0032] The sole part 100, 200 further comprises an outsole 150, 250 with a wear surface 151, 251. The wear surface 151, 251 is arranged to rest on a horizontal ground surface 10 in the upright use orientation of the sole part 100, 200.

[0033] The outsole 150, 250 can be made from a natural or synthetic rubber material, such as TPU, other polymer materials or any other high-durability wear material.

[0034] As is illustrated in Figures 1-5, the outsole 150 can be made in the form of one single material body running across the entire length L of the sole part 100. However, as is shown in

[0035] Figures 6-11, the outsole 250 can also be provided in the form of two or more disjoint parts together forming the wear surface 250.

[0036] Furthermore, the sole part 100, 200 comprises a protective layer 130, 230, arranged to prevent sharp objects from penetrating through the sole part 100, 200 and into the foot of a user wearing the shoe 20 when the user steps on said sharp object.

[0037] Such a protective layer 130, 230 is sometimes called a "puncture-resistant plate" and can be made from any tear-resistant material. In particular, it may comprise ceramic, carbon or similar tear-resistant fibers or may even be made from a woven or non-woven material made from such fibers.

[0038] The protective layer 130, 230 can be rigid, such as comprising a metal insert or similar. However, in some embodiments the protective layer 130, 230 is flexible. For instance, it can be made from woven or non-woven textile material, made from tear-resistant fibers of said type. The protective layer 130, 230 is typically designed to resist the penetration of a sharp object, such as a nail, when stepped upon using the force of a user wearing the shoe 20 landing on the sharp object with the full weight of the user.

[0039] Conventionally, in shoes having a protective layer the protective layer is often provided above the cushioning midsole, between the foot of the wearing user and the cushioning midsole. One reason for this is that the travel distance for a sharp object upwards through the midsole before it strikes the protective layer is then longer, providing improved protection. Also, having the protective layer 130, 230 further up in the sole part 100, 200 provides better protection from nails and similar entering the shoe 20 obliquely, from a side of the shoe 20.

[0040] However, in embodiments of the present invention the protective layer 130, 230 is instead arranged further down in the sole part 100, 200, between the cushioning midsole 110, 210 and the outsole 150, 250. Hence, the protective layer 130, 230 is then arranged below the cushioning midsole 110, 210 in the upright use orientation, with the cushioning midsole 110, 210 between the foot of the wearing user and the protective layer 130, 230.

[0041] Furthermore, and as illustrated in the Figures, the cushioning midsole 110, 210 defines an overall upwards concave shape, as viewed in said upright use orientation and in a vertical cross-section perpendicular to the lateral direction W. Such an upwards concave shape is defined by it being bowl-shaped in said upright use orientation, the shape drawing upwards at a front end 101, 201 of the sole part 100, 200 and/or at a back end 103, 203 of the sole part 100, 200. The upwards concave shape may bulge regularly or irregularly across the entire length L of the cushioning midsole 110, 210, or be locally (partially or section-wise) straight or even convex in said vertical cross-section. What is important is that the overall, general shape defined by the cushioning midsole 110, 210 is upwards concave, as seen from the front end 101, 201 to the back end 103, 203 and taking into consideration the entire longitudinal length L of the sole part 100, 200.

[0042] For instance, as is illustrated in Figures 1-5, the upwards concave shape can have a section near a longitudinal L midpoint of the sole part 100, 200 that locally has a smaller radius of curvature, in the vertical cross-section that is perpendicular to the lateral direction W. Such section can include a locally concave and/or a locally convex part. Figures 1-5 also show that a back part of the upwards concave shape, running from the longitudinal L midpoint backwards, towards the back end 103, 203, can be generally straight or only involve a slight upward concave shape.

[0043] Furthermore, as is illustrated in Figures 6-11, the upwards concave shape can have a section near the longitudinal L midpoint of the sole part 100, 200 that is locally flat or upward convex in the vertical cross-section that is perpendicular to the lateral direction W.

[0044] Generally, the upwards concave shape may comprise at least a locally upwards concave part running from the front end 101, 201 to a point maximally 3 cm from said longitudinal L midpoint of the sole part 100, 200. In addition to this, the upwards concave shape may comprise at least a locally upwards concave part running from the back end 103, 203 to a point maximally 3 cm from said longitudinal L midpoint of the sole part 100, 200.

[0045] The upwards concave shape can be upwards concave both along the longitudinal direction L and along the lateral direction W. However, in some embodiments the upwards concave shape is upwards concave along the longitudinal direction L but is generally flat, or at least not decidedly upwards concave, along the lateral direction W.

[0046] Then, the protective layer 130, 230 can be arranged to follow the upwards concave shape described by the cushioning midsole 110, 210. In other words, an upwards-facing surface of the protective layer 130, 230 can have a shape which is complementary, at least in said vertical cross-section, to a corresponding downwards-facing surface of the cushioning mid-sole 110, 210 in turn defining said upwards concave shape.

[0047] It is hence realized that the cushioning midsole 110, 210 can be arranged to define the upwards concave shape of the protective layer 130, 230. However, additional material may be provided between the cushioning midsole 110, 210 and the protective layer 130, 230, such additional material either affecting the upwards concave shape or not affecting the upwards concave shape (the latter alternative for instance being the case by the additional material having a uniform thickness). At any rate, what is said herein regarding the properties of the upwards concave shape defined by the cushioning midsole 110, 210 is generally true and applicable also for the upwards concave shape of the protective layer 130, 230.

[0048] In some embodiments, the protective layer 130, 230 is directly or indirectly attached to the cushioning midsole 110, 210 so that it flexes or bulges with the rest of the sole part 100, 200 as the user moves when wearing the shoe 20, and in particular when the cushioning midsole 110, 210 as a result thereof bends and flexes. For instance, the protective layer 130, 230 can be fastened to the cushioning midsole 110, 210 using a glue joint between the two and/or the protective layer 130, 230 can be trapped between the cushioning midsole 110, 210 and another layer of the sole part 100, 200 in turn fastened to the cushioning midsole 110, 210, such as outsole 150, 250.

[0049] A protective layer 130, 230 of the presently described type, being arranged below the cushioning midsole 110, 210 and having a shape that is concave upwards in said vertical cross-section, provides for a more comfortable shoe 20 as compared to when the protective layer 130, 230 is arranged above the cushioning midsole 110, 210.

[0050] Furthermore, the present inventor has realized that that a concave protective layer 130, 230 arranged under the cushioning midsole 110, 210 in many cases will provide a superior protection from sharp objects penetrating from below, since the concave shape will increase the chance of the sharp object striking the protective layer 130, 230 at an oblique angle, different from 90°. When sharp objects strike the protective layer 130, 230 at such an oblique angle they tend to slide along a downwards-facing surface of the protective layer 130, 230 instead of going straight into the protective layer 130, 230, and as a result the risk of the sharp object penetrating completely through the protective layer 130, 230 is decreased. In particular, this is the case when the upwards concave shape has a local and/or global radius of curvature of at the most 1 m.

[0051] As is illustrated in Figures 6-11, the sole part 200 can furthermore comprise an additional cushioning layer 210 arranged to cover only the heel of the sole part 200. Such an additional cushioning layer 210 can then be arranged between the outsole 250 and the protective layer 230, and is then disjoint to the cushioning midsole 110, 210.

[0052] In some embodiments of the present invention, the protective layer 130, 230 can be arranged in a cavity 111, 211 of the midsole 110, 210. The cavity 111, 211 may open downwards in the upright use orientation. The cavity 111, 211 may also define the upwards concave shape of the protective later 130, 230. The cavity 111, 211 may be defined so that peripheral edges of the cushioning midsole 110, 210 defining the cavity 111, 211 extend downwards, in the upright use orientation, so that the protective layer 130, 230 is completely accommodated in the cavity 111, 211. The cavity 111, 211 can have a bottom surface arranged to face downwards in said upright use orientation, the bottom surface defining the upwards concave shape.

[0053] The protective layer 130, 230 can be fastened to the rest of the sole part 100, 200 by being glued or otherwise attached to the cushioning midsole 110, 210 at an upper surface of the protective layer 130, 230 being in direct contact with said downwards-facing bottom surface of the cavity 111, 211, and/or by the protective layer 130, 230 being trapped in a closed compartment formed in the cavity 111, 211 by the cushioning midsole 110, 210 together with a different layer (such as a shank 140, 240, see below) arranged under the protective layer 130, 230, in the upright use orientation, the different layer then being attached to said peripheral edges of the cushioning midsole 110, 210.

[0054] As mentioned, in some embodiments of the present invention the sole part 100, 200 further comprises a shank 140, 240. The shank 140, 240 can be arranged between the midsole 110, 210 and the outsole 150, 250.

[0055] Moreover, such a shank 140, 240 can be made from carbon fiber material or any other suitable material, and has the effect to absorb, by resiliently bending, the energy delivered by the user, wearing the shoe 20, placing his foot onto the ground 10, and then to deliver this energy back to the user when lifting the foot, by spring action. Using such a shank 140, 240 hence provides improved walking or running energy management for the user wearing the shoe 20 by storing the energy during each stride and returning the stored energy to be used in the next stride. The shank 140, 240 is generally rigid and form-stable but resilient. In other words, it can be bent as a spring so as to store available energy, but will return to its original shape when not subjected to a bending force. The shank 140, 240 is also typically more resistant to torsion flexion than to bending in the above-discussed vertical cross-section perpendicular to the lateral direction W.

[0056] Generally, the shank 140, 240 can be or comprise as a part-component a stiff and resilient insole arranged to, by spring action, mechanically store and release energy during a step performed by the user.

[0057] Such stiff and resilient insole can extend to the front end 101, 201 of the sole part 100, 200, possibly apart from a longitudinal L distance 102, 202 of at the most 2 cm or even at the most 1 cm. The insole can cover at least 80% of the longitudinal L length of the sole part 100, 200.

[0058] Such shank 140, 240 provides an ergonomic advantage for the user wearing the shoe 20, since when sitting down on his knees the worn shoe 20 will bend less easily at a front part of the shoe 20 causing the wearing user discomfort. In particular, this is the case when the shoe 20 comprises the rigid shoe cap 21.

[0059] To this end, the shank 140, 240 can be designed with a locally varying stiffness, such as due to a varying vertical cross-section and/or varying material properties along the longitudinal direction L, arranged to cause the shank 140, 240 to primarily bend at a predetermined location, such as close to or at the toe joints of a wearing user, when subjected to a bending force by the user's foot. This will cause the toe end of the shoe 20 in a desirable manner rather than bending unpredictably or in a place or way providing discomfort to the wearing user when sitting on his knees.

[0060] Generally, the stiff and resilient insole can be arranged to cover at least 80%, such as at least 90%, of a main longitudinal-lateral L-W extension plane of the sole part 100, 200.

[0061] In some embodiments of the present invention, the shank 140, 240 has a shape that follows the upwards concave shape of the midsole 110, 210 and of the protective layer 130, 230.

[0062] Either or both of the protective layer 130, 230 and the shank 140, 240 can be generally sheet-formed, for instance having an entirely or substantially uniform thickness.

[0063] Since the shank 140, 240 is rigid it forces the protective layer 130, 230 back to its upwards concave shape after the shank 140, 240 is allowed to assume its relaxed-state shape. Generally, the shank 140, 240 can be stiff and resilient, and in particular it can be stiffer and more form-stable in a relaxed state than the protective layer 130, 230.

[0064] The shank 140, 240 provides an improved function of the protective layer 130, 230 in at least two ways.

[0065] Firstly, the shank 140, 240 will force the protective layer 130, 230 to keep an upwards concave shape of the above-discussed type throughout the movement of the shoe 20 when the wearing user stands, walks, runs and otherwise moves about. This is not as easy to achieve only by defining the upwards concave shape by the cushioning midsole 110, 210 in itself. In particular as the material of the midsole 110, 210 ages, and as a result undergoes shape changes, the shank 140, 240 will maintain the defined upwards concave shape.

[0066] Secondly, when the wearing user takes a step or stride in the shoe 20, the resulting resilient bending of the shank 140, 240 will force the upwards concave shape of the protective layer 130, 230 to accentuate. This way, the chance will increase that sharp objects penetrating from below will strike the protective layer 130, 230 at an oblique angle and therefore slide across the surface of the protective layer 130, 230, in turn providing improved protection for the user wearing the shoe 20.

[0067] In particular, the shank 140, 240 can be arranged between the protective layer 130, 230 and the outsole 150, 250. The shank 140, 240 can be arranged in direct physical contact with the protective layer 130, 230. In particular, an upwards-facing surface, in the upright use orientation, of the shank 140, 240 can be arranged in direct physical contact with a downwards-facing surface of the protective layer 130, 230.

[0068] However, in this and in other cases an engagement between the shank 140, 240 and the protective layer 130, 230 can be such that the shank 140, 240, when only considering said engagement per se, is movable in relation to the protective layer 130, 230 across at least part of its horizontal extension when the sole part 100, 200 is in the upright use orientation. In other words, if the shank 140, 240 and the protective layer 130, 230 are fastened one to the other, such as via said direct physical contact between said upwards and downwards facing surfaces, this fastening can be arranged so at least part of said surfaces are not attached one to the other but can move in relation to each other.

[0069] Such relative movement between the shank 140, 240 and the protective layer 130, 230 can be possible in the horizontal plane and/or vertically in the upright use orientation. It is realized that when the sole part 100, 200 is mounted, and possibly mounted as a part of a finished shoe 20, the shank 140, 240 and the protective layer 130, 230 may both be fixed by surrounding materials even if they are not directly attached to each other using a mechanical fastening means such as glue. Also, the shank 140, 240 and the protective layer 130, 230 may be fixed to each other by a partial direct attachment between them. That the shank 140, 240 and the protective layer 130, 230 can move in relation to each other is hence intended to mean that such relative movement is possible given that the material of the shank 140, 240 and/or the protective layer 130, 230 and/or surrounding materials deform, such as elastically, to allow such movement when the sole part 100, 200 is subjected to various bending, compression and shearing forces.

[0070] In some embodiments, the shank 140, 240 is movable in relation to the protective layer 130, 230 along at least 50% of a main longitudinal-lateral L-W surface of the protective layer 130, 230. In particular, such an area of possible relative movement can be a connected area.

[0071] By providing the shank 140, 240 and the protective layer 130, 230 so that they have a certain freedom of movement in relation to each other, the protection from penetrating sharp objects is further improved. The shank 140, 240 can receive the sharp object before the protective layer 130, 230 does, and as the sharp object penetrates through the shank 140, 240 and will start to penetrate into the protective layer 130, 230 it can cause the shank 140, 240 to slide slightly in relation to the protective layer 130, 230, hence effectively directing part of the force from the sharp object in a direction parallel to the downwards facing surface of the protective layer 130, 230. This provides an increased chance of the sharp object sliding across the protective layer 130, 230 and as a result, as described above, decreasing the risk of the sharp object penetrating the protective layer 130, 230 completely.

[0072] To achieve said relative freedom of movement between the shank 140, 240 and the protective layer 110, 120, the shank 140, 240 can be fastened to the protective layer 130, 230 and/or to the midsole 110, 210 along a periphery of the shank 140, 240, such as only along said periphery. For instance (and generally), the shank 140, 240 can be slightly larger than the protective layer 110, 120 in said main longitudinal-lateral L-W plane of extension, so that it with a margin covers the protective layer 110, 120 as viewed from below in said upright use orientation.

[0073] The shank 140, 240 can be fastened directly or indirectly to the protective layer 110, 210 using a glue joint. In this case, and in particular in case the shank 140, 240 is glued directly to the protective layer 110, 210 and/or the glue joint is arranged only or partly along a periphery of the protective layer 110, 210, the glue join may be achieved using an elastic glue, i.e. a glue that has elastic properties once hardened.

[0074] As described above, at least some of the various aspects of the present invention aim at causing sharp objects to strike the protective layer at an oblique angle, so that such sharp objects tend to slide along a downwards facing surface of the protective layer 130, 230 instead of penetrating directly into the protective layer 130, 230. As mentioned, the sliding can result by relative movement between the shank 140, 240 holding the partly penetrating sharp object and the protective layer 130, 230.

[0075] To facilitate such sliding, the protective layer 130, 230 can be made from a tougher and/or less resilient material than the outsole 150, 250. This will result in that the material of the outsole will yield or rupture slightly so as to allow the sharp object to slide across the surface of the protective layer 130, 230. The corresponding can be true with respect to the shank 140, 240 in relation to the protective layer 130, 230.

[0076] In such and in other embodiments, the protective layer 130, 230 can be made from a tougher and/or less resilient material than a hardened glue fastening the outsole 150, 250 and/or the shank 140, 240 to the rest of the sole part 100, 200. For instance, the outsole 150, 250 can be glued directly to the shank 140, 240 and/or to any intermediate material, such as to the additional cushioning layer 220.

[0077] Above, preferred embodiments have been described. However, it is apparent to the skilled person that many modifications can be made to the disclosed embodiments without departing from the basic idea of the invention.

[0078] For instance, the upper 22 can be made in many different, per se conventional, ways.

[0079] The sole part 100, 200 can comprise additional material layers, and the detailed design thereof can differ from the ones exemplified in the Figures.

[0080] Hence, the invention is not limited to the described embodiments, but can be varied within the scope of the enclosed claims.

Claims

1. Sole part (100,200) for a shoe (20), the sole part (100,200) having a longitudinal direction (L), a lateral direction (W) and a height direction (H), the sole part (100,200) being associated with an upright use orientation, the sole part (100,200) comprising

a cushioning midsole (110,210);

an outsole (150,250), having a wear surface (151,251) arranged to rest on a horizontal surface (10) in said upright use orientation; and

a protective layer (130,230), arranged to prevent sharp objects from penetrating through the sole part (100,200) when stepped upon by a user of a shoe (20) comprising the sole part (100,200),

wherein the protective layer (130,230) is arranged between the midsole (110,210) and the outsole (150,250),

wherein the midsole (110,210) defines a shape, the shape being overall upwards concave as viewed in said upright use orientation and in a vertical cross-section perpendicular to the lateral direction (W), the shape drawing upwards at a front end (101,201) of the sole part (100,200),

wherein the protective layer (130,230) follows the upwards concave shape, wherein the sole part (100,200) further comprises

a shank (140,240), having a shape that follows the upwards concave shape of the mid-sole (110,210) and that is arranged between the protective layer (130,230) and the outsole (150,250).

2. The sole part (100,200) of claim 1,
wherein the sole part (200) furthermore comprises another cushioning layer (220) arranged to cover only the heel of the sole part (200), the cushioning layer (220) being arranged between the outsole (250) and the protective layer (230).

3. The sole part (100,200) of claim 1 or 2,
wherein the protective layer (130,230) comprises ceramic fibres.

4. The sole part (100,200) of any preceding claim,
wherein the protective layer (130,230) is arranged in a cavity (111,211) of the midsole (110,210).

5. The sole part (100,200) of any preceding claim,
wherein the midsole (110,210) is made from an expanded polymer material.

6. The sole part (100,200) of any preceding claim,
wherein the shank (140,240) is stiffer than the protective layer (130,230), but resilient.

7. The sole part (100,200) of any preceding claim,
wherein an engagement between the shank (140,240) and the protective layer (130,230) is such that the shank (140,240), when only considering the engagement per se, is movable in relation to the protective layer (130,230) across at least part of its horizontal extension when the sole part (100,200) is in its upright use orientation.

8. The sole part (100,200) of claim 7,
wherein the shank (140,240) is movable in relation to the protective layer (130,230) along at least 50% of a main longitudinal-lateral surface of the protective layer (130,230).

9. The sole part (100,200) of any preceding claim,
wherein the shank (140,240) is or comprises a stiff and resilient insole arranged to, by spring action, mechanically store and release energy during a step performed by the user.

10. The sole part (100,200) of claim 9,
wherein the insole extends to a longitudinal (L) extreme front end (101,201) of the sole part (100,200), possibly apart from a distance of at the most 2 cm.

11. The sole part (100,200) of any preceding claim,
wherein the shank (140,240) is fastened to the protective layer (130,230) using an elastic glue.

12. The sole part (100,200) of any preceding claim,
wherein the shank (140,240) is designed with a locally varying stiffness, such as due to a varying vertical cross-section along its longitudinal direction (L), arranged to cause the shank (140,240) to primarily bend at the toe joints of a wearing user when subjected to a bending force by the user's foot.

13. The sole part (100,200) of any preceding claim,

wherein the protective layer (130,230) is made from a tougher material than a material of the outsole (150,250) and/or

the protective layer (130,230) is made from a tougher material than a hardened glue fastening the outsole (150,250) to the rest of the sole part (100,200).

14. The shoe (20) of claim 13,
wherein the shoe (20) is a protective shoe.

15. The shoe (20) of claim 14,
wherein the shoe (20) comprises a protective toe cap (21).

Drawing