Patent Application
20200375312
A sole for a shoe comprising: an outsole having a ground contacting surface and an opposite foot facing surface, the outsole having a peripheral edge defining the outer periphery of the outsole, a midsole having an foot facing surface and an opposing outsole facing surface, the midsole comprising a polymer that is configured to be injected into a mould adapted to define a volume of the midsole, so that the midsole is configured to be positioned between the outsole and the foot of the user during use.
In shoe production there are a number of ways to manufacture a pair of shoes, where the manufacturing method, the choice of material, the form of the upper, the form and material of the midsole, and the form and shape of the outsole have a huge impact in how the shoe performs. There are a number of different types of shoes, such as hiking boots, sport shoes, golf shoes, running shoes where the shoes have different qualities such as the stiffness of the upper, the stiffness of the outsole or midsole, where the qualities of the shoe are controlled by different factors.
One of the important factors for producing a specific type of shoe, that acts in a certain way is the design, shape and hardness of the sole of the shoe. This has traditionally been done by introducing items such as shanks or embedded reinforcement elements to improve the stiffness of the material in a certain area, while maintaining a certain flexibility in other areas or to apply reinforcements to the outer surfaces of the sole in order to change the characteristics of the sole.
In direct injection moulding techniques for shoes, the sole and/or the outsole of the shoe is injected directly to the upper of the shoe, where a last holds the upper, and a mould having the shape of the sole is introduced onto the upper and a thermoplastic material is injected directly onto the upper, fixing the midsole and/or the outsole to the upper. This means that the outsole is injected directly onto the upper, and there is no need for adhering or otherwise fixing the midsole/outsole to the upper.
In direct injection moulding techniques, the introduction of reinforcement elements inside the midsole, requires a modification of the mould and the equipment needed to manufacture the shoe, which is time consuming and may be expensive, in view of simpler shoes, that do not have reinforcement elements, and where the midsole is uniform throughout the shoe. Furthermore, in order to provide complex midsoles, where certain areas are reinforced, while others are not, may require a number of different steps of injection moulding, using a number of different moulds to obtain the required properties. This is both costly and time consuming for manufacturing purposes.
WO 2008/115743 discloses an article of footwear having an upper and a sole structure secured to the upper. The sole structure includes a midsole and an outsole. The midsole has an upper surface and an opposite lower surface. The upper surface defines a plurality of depressions, and the lower surface defines a plurality of indentations extending toward the depressions. The outsole forms projections that extend into the indentations of the midsole, and the outsole has grooves located opposite the projections. This structure increases the flexibility of the midsole and the outsole, as the midsole and the outsole have indentation that reduce the thickness of the sole assembly.
Thus, there is a need to improve the structure of a shoe, where a certain property may be obtained through simpler means, using a simplified design of the shoe, to obtain certain reinforcement properties in the shoe.
In accordance with the invention, there is provided a sole for a shoe comprising: an outsole having a ground contacting surface and an opposite foot facing surface, the outsole having a peripheral edge defining the outer periphery of the outsole, a midsole having an foot facing surface and an opposing outsole facing surface, the midsole comprising a polymer that is configured to be injected into a mould adapted to define a volume of the midsole, so that the midsole is configured to be positioned between the outsole and the foot of the user during use, where the outsole comprises at least a first projection and a second projection that extend from the foot facing surface and in a direction towards midsole, where each projection has a proximal part that is joined/integrated/attached to the foot facing surface and an opposite distal part, so that the distal part of the first projection and the second projection extends into the midsole of the sole, where the first projection and the second projection are positioned adjacent to each other, having a predefined space/volume between the first projection and the second projection, where the polymer material of the midsole extends into the predefined space/volume between the first projection and the second projection so that the polymer material provides a coupling between the first projection and the second projection in an area that is distal to the proximal end of the projection.
By providing an outsole having at least two projections it is possible to use the polymer material of the midsole to connect or interact with each other, and thereby allowing the two projections as well as the midsole material to provide an increased rigidity compared to the midsole material on its own, or each single projection on its own. The polymeric material extending between the two projections will mechanically couple the two projections, so that if a force is applied to one of the projections, the polymeric material will transfer at least part of this force to the other projection and thereby link the two projections. The force applied to the polymeric material may be either compression force, tension force, and/or shearing force, or a combination of any of the aforementioned forces.
An example of this could be if there are two parallel projections that extend upwards into the midsole, intended to increase the rigidity of the sole, and the polymeric material of the midsole couples the two projections to each other along the length of the projection, the two projections and the polymeric material of the midsole in between the projections form a unitary reinforcement element, where the combined reinforcement is more than the reinforcement of the each projection on its own, and more than the two projections, without connecting the two along their length.
By providing at least two projections on the outsole it is possible to reinforce the midsole and the outsole, i.e. the sole of the shoe in a manner that would otherwise only be done with additional elements that would increase the weight of the sole, where the reinforcement element would most likely be in the form of the combined projections/polymer element, and would most likely have a density that is higher than the midsole and/or likely to have a less compressive material than the midsole, or otherwise if it was in a lighter material, would be costly both in material cost and/or manufacturing, if the reinforcement element would be of a carbon fibre, glass fibre, thermoplastic material.
Furthermore, the manufacturing cost of a sole is reduced, as the complexity of the mould and the additional steps that need to be taken to introduce a foreign reinforcement element would be reduced considerably. Furthermore, the adaptability of the production facilities would be increased dramatically, as it is only the shape inner surface of the outsole that would change, if the designers would want to reinforce the sole in a different manner. I.e. the manufacturer could be able to use the same mould to produce a sole that has vastly different properties, as it is only the inner surface of the outsole (foot facing surface) that would change, while the mould would have its original shape, size and form.
It is to be understood that within the meaning of the present invention, the outsole and the midsole are two separate elements, where the outsole is positioned into a mould, and the midsole is injected between the upper and the mould creating a sole of the shoe. Thus, the outsole may be moulded from any type of suitable material, such as TPU or PU, and introduced into the bottom of the mould for the midsole prior to injection moulding. The injection moulding of the midsole may be a type of moulding where a polymeric material is introduced into the mould and the material expands into the free volume of the mould to create the midsole of the shoe, and creating a sole for a shoe, and thereby connecting the outsole to the upper.
When the polymeric material between the two projections is bound to both projections the density and the stiffness of the material in that volume of the sole is different from the density of each material on their own, and have different stiffness than the materials on their own. The thickness, width, height, length of the projection made of the outsole material will influence the stiffness of sole when the polymeric material has been introduced to couple the two projections to each other. This, therefore creates a synergistic effect between the two projections and/or the polymeric material, and thereby creating a synergistic assembly having an increase rigidity compared to the outsole on its own or the midsole of its own.
The polymer material provides a coupling between the first projection and the second projection in order to increase the stiffness of the sole for the shoe. By using the polymer material to provide the coupling, there is no need to provide an adhesive layer between the midsole and the outsole. An adhesive layer between the midsole and the outsole may cause an area of weakness in the construction of the sole, as the adhesion depends on the specific type of adhesive. Many types of adhesives are chemical products that may be seen as damaging to the environment as well as being toxic, and may require protection when the adhesive is being applied to the sole, as well as being toxic when the sole is being disposed of after use. Furthermore, due to environmental protection standards adhesives chemically less toxic than in the past, however the reduction in toxicity has also reduced the adhesion abilities of the adhesive layer. By providing a sole where the outsole is bonded to the midsole without an adhesive, the sole has a reduced amount of toxic material, which means that the material of the shoe is more viable to recycling.
Furthermore, the absence of an adhesive layer reduces the risk that the outsole is released from the midsole during use, and reduces the risk of providing a defective shoe, as it is the polymer material of the midsole that provides the coupling to the outsole. It is well known in the shoe industry that an adhesive is more likely to deter or become non-functional during the lifetime of the shoe, causing the detachment of the outsole from the midsole. Thus, an adhesive free sole structure is a stronger sole structure.
In accordance with the invention, the outsole may be provided in a material that is different from the polymeric material of the midsole. As an example, the outsole may be in a more durable TPU material, while the midsole is of a PU material. Furthermore, the material of the outsole may be more firm or rigid than the polymeric material of the midsole, or may have a higher density than the polymeric material of the midsole. The material of the outsole and/or the midsole may further be of a latex material, rubber, thermoplastic rubber, PVC or any suitable type of TPE.
In one embodiment the area where the first projection and/or the second projection, and/or any subsequent projection, may provide the outsole with a higher rigidity than in an area of the foot facing surface that is adjacent to the first projection and/or the second projection, and/or any subsequent projection.
In one embodiment the area of the outsole where the first projection and/or the second projection are positioned provide a ground contacting surface of the outsole. This means that the projections are capable of transferring force from the ground contacting surface and towards the distal part of the projections when the outsole is in use, and/or when a force is applied to the distal part of the projection, the force can be transferred via the projection in a direction towards the ground contacting surface below the projection.
In one embodiment the thickness of the outsole in the area of the projection may be larger than the thickness of the outsole in an area void of a projection. The thickness may be seen as the height of the outsole from the ground contacting surface to the foot facing surface, where the thickness may be measured along an axis that is substantially normal to the plane of the ground contacting surface and/or the foot facing surface. Thus, the axis extends upwards when the ground contacting surface is positioned on a horizontal surface. This means that the projection may be seen as part of the outsole, and that the projection increases the thickness in a direction from the ground facing surface and towards the foot facing surface.
In one embodiment the first projection and the second projection may have a height that is between 10% to 100% of the height of the midsole. The height of the projection may be controlled in order to increase or decrease the rigidity of the sole, as the coupling of the projections via the midsole material will create a stiffening element. By applying a height of the projections that extend throughout the height of the midsole will increase the rigidity of the sole in the area, where a thickness of 10% of the height of the midsole will provide a slight increase in rigidity. By positioning the height of the projections anywhere between 10% and 100%, the sole may be adapted to have the desired resistance and stiffness in the predefined area, where areas of the sole where the projections are not present the shoe may have an increased flexibility compared to the area where the projections are present.
In one embodiment the first projection has a side wall and the second projection may have a side wall, where the polymer material connects/joins the side wall of the first projection to the side wall of the second projection. The side walls of the projections may be adjacent to each other, so when the polymer material of the midsole fills the space between the two side walls, the polymer material couples the two side walls to each other, and thereby couples the two projections in a mechanical manner to each other.
In one embodiment the first projection may have a height that is different from the second projection. By providing projections that are of a differing height, it is possible to reduce the stiffness of the sole in a direction towards the projection that has a lower height than the adjacent projection, or vice versa. Thus, it is possible to gradually reduce the stiffness of the sole in a certain direction, based on the configuration of the projections on the outsole.
In one embodiment the polymer material fills the predefined space/volume between the first projection and the second projection. When the polymeric material is injected into the mould, where the outsole having the projections is present, the polymeric material seeks to fill all void spaces inside the mould as it expands. Thus, by creating voids in the predefined space/volume between the projections the polymeric material will expand and fill up the space and thereby filling up the void between the projections.
In one embodiment the first projection and/or the second projection extend a predefined length along a plane/surface of the foot facing surface of the outsole. By extending the projections along a predefined length of the foot facing surface, it is possible to extend the stiffening projections along the length or width of the shoe, where the extension ensures that the projections extend a length that is longer than the width of the projections. Thus, the length of the projection increases the surface area to which the projections are capable of bonding with the polymeric material of the midsole, and thereby is capable of providing an extended stiffening element along the outsole and thereby the sole of the shoe.
In one embodiment the first and/or the second projection extend from a peripheral edge of the outsole and in a direction inwards towards a central part of the outsole. In some embodiments the projections may extend from a peripheral edge of the outsole, e.g. from a peripheral part in a heel area, from a peripheral part of a forefoot area, from a peripheral part of an arch area of the sole. The projections may extend inwards towards the body of the outsole, where the direction of the projection may be in any direction in a direction inwards from the peripheral edge.
In one embodiment the outsole further comprises a third projection, fourth projection or a further subsequent projection that is adjacent to another projection, and where a space is defined between the projections allowing the midsole to couple the two projections to each other. By providing further projections, it may be possible to adjust and provide areas of increased stiffness of the sole in a larger area of the sole. One example could be where a plurality of projections are provided in the heel area of the shoe, where it may be advantageous to increase the stiffness of the heel area in order to minimize dampening during heel impact during gait. Thus, a plurality of projections could be provided in areas of the heel where the heel strike occurs, and e.g. its surrounding area. I.e. on the back part and medial side of the heel on the outsole. Thus, when the polymeric material has been introduced, the stiffness of this area has been increased. Alternatively, this plurality of projections could be provided in any area of the outsole, i.e. the hell area, arch area or forefoot area, and both on the medial and lateral side of the sole.
In one embodiment the sole may comprise a direct injected midsole. The polymeric material of a direct injected midsole is advantageous in relation to providing the coupling between the projections, as the polymeric material bonds with the projections and the outsole while it is expanding and cooling down after the material has been injected into the mould. The direct injection moulded midsole may therefore be directly bonded to the upper and/or the outsole, which means that there is no adhesive layer between the midsole and the upper and/or the outsole. When the sole material expands during the injection moulding, the injected material expands, and when the material cures the injected material creates a chemical bond between the upper facing surface of the midsole and/or the ground facing surface of the midsole.
In one embodiment the midsole may be moulded directly to the foot facing surface of the outsole and a lower surface of an upper. This means that during the manufacturing of the sole, the upper and the outsole may be positioned in a mould, where the upper and the outsole are separated by an injection cavity. The material of the midsole may subsequently be injected into the injection cavity, allowing the material of the midsole to fill the cavity. The material of the midsole may therefore be connected the outsole to the upper, where the material of the midsole connects the projections on the midsole to each other, and attaches the outsole to the upper.
In one embodiment the first and/or the second projection are solid from a proximal part of the projection to the distal part of the projection. The proximal part of the projection extends from a foot facing surface of the outsole and in a direction towards the foot and may terminate in a distal part, which may be seen as the top part of the projection. Thus, the projection may be seen as being solid in a cross sectional view, where the material of the outsole extends from a first side wall of a projection to an opposite second side wall of the same projection. Optionally, the material of the projection may be uninterrupted from a proximal part of the projection towards the distal end of the projection, and/or from one side of the projection towards the opposing side of the projection.
In one embodiment the ground facing surface of the outsole may be uninterrupted in the area where the projection extends from the foot facing surface of the outsole. This means that in the area where the projection extends from the foot facing surface of the outsole and into the midsole, the ground contacting surface does not have an indentation in the area where the projection extends from the foot facing surface.
In one embodiment the first and/or the second projection, or any subsequent projection may have a width, which extends from a first side wall of the projection towards a second side wall of the projection. Optionally the width of the projection may be larger in a proximal part of the projection than in a distal part of the projection.
In one embodiment the proximal part of the projection may be joined/integrated/attached to the foot facing surface across its entire width from one side wall to the opposing side wall seen in a cross sectional view of the projection.
In one embodiment the first and the second projection may extend in parallel along the foot facing surface. It may be advantageous that the projections extend in parallel along the foot facing surface, as the bonding of the polymeric material creates a balanced or constant stiffness along the length of the projections when the sole has been moulded.
In one embodiment the first and the second projections may extend at an angle towards each other. This means that the projections are not parallel to each other, but are adapted so that an imaginary axis of the projections is capable of intersecting at some point in the plane of the foot facing surface of the outsole. Thus, the projections may have a longitudinal axis where the longitudinal axis of the two projections may be seen as having a V shape, where the intersection may be in a direction towards the sole or in the opposite direction.
In one embodiment the first and/or the second projection may have a variable height along the length of the projection. This means that the projection may have a height in one area which may be 70% of the thickness of the midsole, and along the length of the projection the height of the projection may either increase or reduce along its length. Furthermore, the projection may have numerous heights, where it may have a wavy form seen in the height direction, so that it may start at a low height and increase in height along its length, and then reduce again in height when extending further along the length of the projection.
In one embodiment the first and/or the second projection may have an annular shape seen from above. Thus, the first and/or the second projections may be seen as annular shapes that are positioned adjacent to each other, similar to the annular shapes of a target, i.e. a plurality of different sized ring shapes having a space between them for the polymeric material to enter the void between the two projections.
In one embodiment the first and/or the second projection may have first width in the proximal part of the projection and a second width in the distal part of the projections, optionally where the first thickness is different than the second width. The differing width allows the stiffness to be varied along the width of the sole, where the sole in the area close to the outsole may be relatively stiff, while the stiffness of the sole reduces when in the area close to the upper (i.e. in an upper part of the sole).
In one embodiment the first and/or the second projection may have a variable width along the length of the projection. Thus, the projections may have a first thickness at one end, while having another width at the opposing end. This helps to provide specific stiffness in certain areas, where the increased width reduces the amount of polymeric midsole material, where the projections are thick and increases the amount of polymeric material between the projections in areas where the projections are thinner.
Various exemplary embodiments and details are described hereinafter, with reference to the figures when relevant. It should be noted that the figures may or may not be drawn to scale and that elements of similar structures or functions are represented by like reference numerals throughout the figures. It should also be noted that the figures are only intended to facilitate the description of the embodiments. They are not intended as an exhaustive description of the invention or as a limitation on the scope of the invention. In addition, an illustrated embodiment needs not have all the aspects or advantages shown. An aspect or an advantage described in conjunction with a particular embodiment is not necessarily limited to that embodiment and can be practiced in any other embodiments even if not so illustrated, or if not so explicitly described.
The invention is explained in detail below with reference to the drawings, in which
The use of the terms “first”, “second”, “third” and “fourth”, “primary”, “secondary”, “tertiary” etc. does not imply any particular order, but are included to identify individual elements. Moreover, the use of the terms “first”, “second”, “third” and “fourth”, “primary”, “secondary”, “tertiary” etc. does not denote any order or importance, but rather the terms “first”, “second”, “third” and “fourth”, “primary”, “secondary”, “tertiary” etc. are used to distinguish one element from another. Note that the words “first”, “second”, “third” and “fourth”, “primary”, “secondary”, “tertiary” etc. are used here and elsewhere for labelling purposes only and are not intended to denote any specific spatial or temporal ordering.
Furthermore, the labelling of a first element does not imply the presence of a second element and vice versa.
It is to be noted that the word “comprising” does not necessarily exclude the presence of other elements or steps than those listed.
It is to be noted that the words “a” or “an” preceding an element do not exclude the presence of a plurality of such elements.
It should further be noted that any reference signs do not limit the scope of the claims, that the exemplary embodiments may be implemented at least in part by means of both hardware and software, and that several “means”, “units” or “devices” may be represented by the same item of hardware.
In the following the reference numbers relating to similar parts of the invention of different embodiments will have the same reference numbers
The ground contacting surface 3 of the outsole 1 may have any type of suitable surface, where the outsole may comprise treads 8, or alternatively comprise spikes, cleats, pads, or any type of suitable ground contacting surface that is suitable for the specific use of the outsole 1.
In the embodiment shown in
By having the central projections 9 extending a shorter longitudinal distance than the peripheral 12 and medial 13 projections, it is possible to maintain a softness of the sole in the heel area, especially in the area 16 that is configured to be below calcaneus bone of the foot, and thereby improving the comfort level of the sole, while the central projections 11 and the peripheral projections 12, 13 may be configured support the calcaneus from the back and from the medial and lateral sides.
The projections 11, 12, 13 of the outsole 1 are provided in such a way that there is a space 24 between any of the two projections 11, 12, 13, where the polymeric material of the midsole 18 is intended to fill when the midsole is injected in a space between the upper 19 and the outsole 1. Here it can be seen that it is the midsole material 18 that connects the outsole 1 to the upper 19. The polymeric material of the midsole 18 that fills the space 24 between the projections 11, 12, 13 ensures that at least two adjacent projection 11, 12, 13 are coupled to each other, so that the synergy of the midsole material and the projections 11, 12, 13 create a reinforcement element in the sole 17 of the shoe, where the reinforcement element reinforces a predefined area of the sole 17. In this embodiment the reinforcement of the sole 17 is intended in the heel area of the sole. This also allows the production of a shoe without introducing a separate reinforcement element into the shoe, such as a shank or a stiffening rib inside or outside the midsole.
Furthermore, the width and the height of the projections, in all of the embodiments may be adjusted, as well as the distance between the projections, in order to provide a suitable rigidity of the sole.
It is to be understood that the person skilled in the art would have no problem in combining one embodiment shown in the invention with the other embodiments disclosed.
Although features have been shown and described, it will be understood that they are not intended to limit the claimed invention, and it will be made obvious to those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the claimed invention. The specification and drawings are, accordingly to be regarded in an illustrative rather than restrictive sense. The claimed invention is intended to cover all alternatives, modifications, and equivalents.
| Number | Date | Country | Kind |
|---|---|---|---|
| 18158538.1 | Feb 2018 | EP | regional |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/EP2019/054547 | 2/25/2019 | WO | 00 |
