Patent Application
20250204644
The present invention relates to a heeled shoe, also referred to as a pump, high heel, or stiletto, having a support structure comprising a sole, particularly an insole, and a heel.
Shoes with a significantly elevated rearfoot region compared to the forefoot region, known as heeled shoes, have already been especially popular among women for many years. For instance, heeled shoes can be defined by the fact that the rearfoot region, also referred to as the heel region, is positioned at least 2 cm higher than the forefoot region. This difference in height is primarily attained by the height of the heel and generally gives the person wearing the shoe a particularly elegant appearance.
The insole refers to the layer of the shoe sole that is oriented towards the foot or footbed. The shoe sole generally includes everything that exists under the foot in a shoe, such as the outsole, midsole, heel, frame, insole and footbed. The upper part of the shoe, also referred to as the shaft, is usually attached to the insole. Therefore, the insole typically forms the foundation of a shoe and provides it with stability and shape retention.
The insole usually has a shape that corresponds to the foot or footbed, specifically as a plate designed as thin as possible which extends over the entire foot, i.e. from the forefoot region through a midfoot region to the rearfoot region, and is generally a full-surface plate with raised side edges. Today, insoles are generally produced from leather, thermoplastic materials, specially impregnated cardboard, or felt.
While in flat shoes, the weight force of a person or the pressure acting on the human foot is mostly evenly distributed across the forefoot-, midfoot- and rearfoot region, the main load, in heeled shoes, due to the elevated heel position, is concentrated primarily on the forefoot region. In particular, in the case of extremely high and thin heeled shoes, especially the front part of the foot, i.e., the ball of the foot, is exposed to stress. This can result in heeled shoes being perceived as uncomfortable and unpleasant to wear, especially compared to flat shoes. It is known that with a certain flexibility of the heeled shoe, along with targeted footbed support, local support for the foot and thereby improved pressure distribution, particularly over the entire footbed, and consequently increased wearing comfort can be achieved.
In addition to the aforementioned flexibility of the heeled shoe, particularly in the region of the sole of the foot, the strength and stability of the heeled shoe are among the most important factors in the development and manufacture of a heeled shoe to ensure sufficient stability and the transmission of movement originating from the foot while walking. Thus, in order to ensure stability, the connection between the sole and the heel must especially be permanently rigid and firm. This is often only made possible with particularly strong materials, especially in the case of very narrow or thin heels, such as so-called stiletto heels. Therefore, heeled shoes usually comprise a thin metal plate serving as the insole, the former being connected to the heel in the transition region towards the heel via metallic screws, in particular screws made of titanium. However, this makes such shoes relatively heavy. Moreover, the production and assembly of such shoes are particularly complex and cost-intensive. This design especially requires coordination between at least three specialized suppliers, which may lead to a significant increase in complexity and a slowdown in production. In times of ever faster production cycles, the often manually conducted adjustment of the insole and outsole is therefore becoming increasingly problematic.
In particular, to avoid the relatively high weight of such shoes, lightweight materials have increasingly been used. Specifically, epoxy resin or plastic has been employed in the heel of the shoe. A shoe with a heel that has a lightweight inner core is known, for example, from EP 2 143 354 A1.
However, it has been shown that the use of epoxy resin or plastic cannot completely prevent the heel or shoe from breaking apart due to the material properties. Therefore, epoxy resin or plastic is usually only used in heeled shoes as a supportive, particularly strength-enhancing component on the otherwise typical metallic parts. In particular, such typical parts are additionally encased with strength-enhancing components. This, however, again results in a relatively high weight of the shoe, a relatively high manufacturing and assembly effort, and also a relatively thick-walled shoe structure, which can negatively affect the shoe's external appearance.
Moreover, it has been found that in such shoes—due, in particular, to vibrations and shocks while walking—the metallic connecting screws can dig into adjacent softer materials and thereby become loosened, which can lead to the heel breaking off or detaching.
Finally, the sustainable disposal or even recycling of such a heeled shoe is often not possible without destroying the parts of the shoe and/or material, thus rendering them unusable due to the regularly applied fusion of the basic components, such as the sole.
The objective of the present invention is therefore to provide a heeled shoe that improves at least one of the aforementioned disadvantages, and, in particular, has the flexibility required for comfortable wear, the stability required for safe use, and the uncomplicated construction required for easy and cost-effective manufacturing and assembly.
According to the invention, this object is attained by a heeled shoe having the features outlined in the main claim. Advantageous embodiments and further developments of the invention are disclosed in the subsidiary claims, the description and the figures.
The heeled shoe according to the invention comprises an insole, which includes a front insole arranged in a forefoot region and a separately formed rear insole extending over a midfoot- and rearfoot region. This allows for the flexibility required in the forefoot region for comfortable wear and smooth foot rolling, as well as the stability and rigidity required in the rearfoot region for secure standing and walking, thereby maintaining the shape of the heeled shoe. In particular, the rear insole can form a particularly dimensionally stable foundation for supporting the shoe, while the front insole, as a relatively flexible element, can allow for a certain degree of bending and twisting of the heeled shoe while walking.
For this purpose, at least the rear insole, which is designed as a flat component, is made of a fiber-reinforced plastic. In particular, the entire rear insole can be produced exclusively from a fiber-reinforced plastic. The fibers can be natural fibers, such as flax, or industrially produced fibers, such as carbon fiber. The fibers can, in particular, provide the required strength to the plastic without necessitating an additional casing material to support a load-bearing core.
This can achieve a significant reduction in the weight of the shoe, while the two-part design can create a certain cushioning effect within the shoe, significantly enhancing wearing comfort. Furthermore, the manufacturing complexity can be reduced, particularly in that the insole and the outsole can be manufactured as a single component or at least from the same material, which can be sourced from a single manufacturer, thereby significantly simplifying the supply chain and enabling particularly fast and digital production. Since the new chassis of the heeled shoe is now primarily based on a single component, the material can further also be more easily separated from other components, such as leather, at the end of the life cycle of the shoe, and directly recycled or reused. In the case of flax, the material is even obtained naturally, reducing the dependence on environmentally harmful chemicals and fossil raw materials.
An insole manufactured in this way is particularly rigid, so that the arrangement of an additional supporting frame or plate, especially a metallic frame or a metallic plate is not necessary and can be avoided, resulting in an overall particularly lightweight shoe. The reinforcing fibers in the plastic can be arranged in multiple layers within the rear insole. Preferably, in the rear insole, two fiber layers are oriented in the direction of the longitudinal extension of the rear insole, while additional fiber layers are arranged at other, particularly varying angles to the longitudinal extension. The number of fiber layers preferably decreases towards the forefoot region, thereby allowing greater flexibility in the forefoot. The finished rear insole, formed as a thin-walled carbon shell, can thus have, for example, a material strength or thickness of between 1.0 to 2.5 mm, with a preferred material thickness between 1.5 and 2.0 mm, and most preferably about 1.8 mm. It is fundamentally possible, of course, for the front insole to be also made of a fiber-reinforced plastic.
Moreover, such an insole made of fiber-reinforced plastic allows for particularly precise and individually customizable geometry and shaping of the sole of the foot. In particular, the rear insole can have a geometry that is individually adapted to a previously measured foot. For example, the size and shape, and/or the elevations and depressions arranged on the upper side of the rear insole, can be individually adapted according to the previously measured foot and the resulting optimal design of the sole geometry. The thus shaped surface of the rear insole can, depending on the further construction of the heeled shoe, alternatively or additionally, support and/or define the shape of an additionally arranged footbed. This allows for particularly high wearing comfort.
The front insole and the rear insole are preferably manufactured and/or designed as two separate parts, with the rear insole and the front insole being partially overlapping in the forefoot region. In particular, the rear insole can partially cover the front insole, meaning that it lies on the upper side of the front insole that is facing the foot. This allows for sufficient stability in the mid- and rearfoot region and particularly high flexibility in the forefoot region of the heeled shoe, enabling the foot to roll while walking. The front and rear insoles can be connected to one another, for example, by using an adhesive. This creates a permanently secure and firm connection between the front insole and the rear insole.
In a preferred embodiment of the invention, the flat rear insole has an upper side and an underside, with the upper side facing a footbed and the underside being arranged at least partially visible from the outside, particularly in a section between the heel and the front insole. Specifically, the insole made of fiber-reinforced plastic is not surrounded by a covering material, at least in this section. This allows both high inherent stability and a particularly thin-walled shoe form, giving the shoe a particularly low inherent weight and enabling a particularly elegant appearance of the heeled shoe. It should be understood that the term “visible from the outside” refers to the possibility of direct visual contact with the rear insole, in particular, without another material layer, especially a covering layer, preventing this visual contact.
Preferably, a footbed and a shoe upper are arranged on an upper side of at least the rear insole, in particular, abutting the rear insole. The shoe upper typically includes a shoe upper structure with a shaft that laterally surrounds the foot of the person wearing the shoe. The footbed can extend beyond the rear insole into the region of the front insole. The footbed is preferably formed as a single piece. This allows for a particularly secure hold of the foot in the heeled shoe and enables direct control of movement of the heeled shoe.
A glued connection can fundamentally be provided between the heel and the rear insole. Preferably, a plug connection is provided for a particularly firm connection between the heel and the rear insole. Such a plug connection generally refers to the joining of components of the heel on the one hand, and corresponding components of the rear insole on the other hand. This can be, for example, a connection between at least one pin and at least one corresponding hole. The plug connection preferably includes only components which form part of the heel and/or the insole. In particular, the plug connection does not include any additional separate parts, such as screws. This, on the one hand, allows for a particularly firm connection between the insole and the heel and, on the other hand, for a particularly uncomplicated and cost-effective production and assembly of the heeled shoe.
For example, at least one protruding pin can be provided on a side of the heel facing the insole and a corresponding recess can be provided on the rear insole. The pins inserted into the recess can additionally be glued to the side surfaces of the recess. Particularly preferably, three pins protruding in the direction of the insole are provided on the heel, while three corresponding recesses are provided on the insole. This allows the plug connection to be designed as a plug-in mechanism, enabling both a particularly firm connection between the insole and the heel and a particularly uncomplicated and cost-effective production and assembly of the heeled shoe. The at least one pin preferably comprises the same material as the heel in this region.
Particularly preferably, the pin is not made of metal. The recesses can be formed, for example, as a blind hole or a fully penetrating hole.
The pins can be arranged parallel or offset to each other, particularly in a regular pattern on the respective surface of the heel or the insole. The pins can be straight, curved, tilted or even serrated along their length. In particular, the pins can extend from the upper side of the heel or the underside of the insole at a predefined angle. Specifically, the pins can be formed at an angle between 3° and 60° relative to the respective surface. In this context, all of the pins are generally inclined towards the rear end of the heeled shoe, but they can also be inclined in different directions, which can further enhance the connection between the heel and the insole. The pins can have different cross-sectional shapes, for example round, elliptical or angular. As a result, the connection between the heel and the insole can also be reinforced.
The pins may have an end face at a lateral end, which is preferably formed substantially horizontally when the heeled shoe is in a standing position. It is also possible, particularly in the case of a fully through-going recess in the insole, that the end face is visible on the upper side of the insole after the pin is fully inserted into the recess. In this case, the end face of the pin can advantageously correspond to the section of the upper side of the insole, so that the end face of the pin and the upper side of the insole form a flush surface without any protrusion from the heel.
The plug connection preferably includes an interference fit between at least one protruding pin and a recess arranged corresponding to the pin. This allows for both a particularly strong connection between the insole and the heel, as well as a particularly straightforward and cost-effective production and assembly of the heeled shoe.
In a preferred embodiment of the invention, all components of the heeled shoe or the entire heeled shoe, are made of non-metallic materials. This non-use of metal results in additional advantages, such as with regard to the increasingly important societal issues of sustainability and biodegradability of products. Thus, especially biodegradable materials can be used for the shoe components. Furthermore, the advantage arises that when passing through security checkpoints, such as in public buildings or airports, it will no longer be necessary to remove the shoes to pass through a metal detector, which is particularly undesirable when wearing nylon stockings, which are often worn in combination with heeled shoes, and which are prone to runs.
In a further development of the invention, the front insole has a particularly flat recess on an upper side facing the footbed, into which recess a cushioning element is inserted. The cushioning element is intended to allow for a certain degree of immersion of the forefoot during walking and the associated rolling motion of the foot. The foot of a person wearing the shoe can be properly braced or pressed into the shoe through the slightly softer material of the cushioning element compared to the front insole. This allows for such a large connection surface between the shoe and the foot that a particularly high level of wearing comfort can be achieved.
The cushioning element can extend across the entire forefoot region, particularly over almost the entire width and/or almost the entire length of the front insole. Advantageously, the cushioning element can be designed as a flat shock insert. This allows it to be fully inserted into the corresponding recess in the front insole. The cushioning element can be fixed in the recess by using an adhesive. The cushioning element can have a thickness or material strength of between about 1 and 15 mm, preferably between 8 and 12 mm, and most preferably about 10 mm. The material thickness can vary across the width and length of the cushioning element. In particular, certain regions of the cushioning element can be made thicker than other regions. It may also be provided that the rear insole extends over the cushioning element. Additionally, it may be provided that the rear insole is connected to the cushioning element. For example, the rear insole may be glued to the cushioning element.
Particularly preferably, an outsole is arranged on an underside of the front insole. The outsole can lie directly on the underside of the front insole. The outsole can be formed exclusively in the region of the front insole, particularly in the forefoot region. Thus, the outsole—alongside the heel tip located on the heel—can form the only contact surface of the shoe with the ground on which the heeled shoe stands. The outsole serves primarily to protect the front insole. It is typically made of rubber.
Particularly preferably, at least one of the front insole, the heel and the cushioning element is produced from an expanded thermoplastic polyurethane, called ETPU for short. In particular, it may be provided that the front insole and/or the cushioning element inserted therein is made of an ETPU. In addition, at least a core of the heel may also be made of an ETPU. This allows the heeled shoe to have a particularly low weight while simultaneously maintaining particularly high dimensional rigidity.
An exemplary embodiment of the invention is explained in more detail below with reference to the figures. There are schematically shown in:
The heeled shoe 100 is characterized by the fact that the footbed 5, or a foot within the shoe, is positioned at least 2 cm higher in a rearfoot region 22 than in a forefoot region 20. This is primarily achieved through the arrangement and design of the heel 4. The forefoot region 20 extends in the longitudinal direction of the heeled shoe 100 from a distal end of the toes to approximately a distal region of the metatarsal bone. The midfoot region 21 extends in the longitudinal direction of the heeled shoe 100 from approximately the distal metatarsal bone to a distal end of the heel joint. The rearfoot region 22 extends in the longitudinal direction of the heeled shoe 100 from approximately the distal end of the heel joint to the proximal end of the heel.
The heeled shoe 100 has a distal or front half and a proximal or rear half, separated by a central transverse axis arranged across its longitudinal extension, with the central transverse axis located approximately in the region of the proximal metatarsal bones. Furthermore, the heeled shoe 100 has a lateral outer foot side and a medial inner foot side, separated by a longitudinal axis.
The insole 1 together with the heel 4, serves as a load-bearing structure of the heeled shoe 100, providing the shoe with stability and shape retention. The insole 1 is designed as a relatively thin, flat and partially curved plate, in particular, with a shape corresponding to the foot or footbed. It extends, in particular, from the forefoot region 20 through the midfoot region 21 to the rearfoot region 22. The shoe upper 6, also referred to as the shaft, is attached to the insole 1. Typically, an outsole is arranged on the underside of an insole; in the present case, an outsole 7 is provided only in the forefoot region 20.
The insole 1, as shown particularly in
The heeled shoe 100 thus only makes contact with the ground on which the shoe stands through a so-called heel tip 8 located on the heel 4 and the outsole 7 arranged on the underside 18 of the front insole 2.
To achieve sufficient stability and strength, particularly for the rear insole 3, while simultaneously maintaining a relatively thin-walled profile of the load-bearing plate, it is proposed according to the invention that at least the rear insole 3 is made of a fiber-reinforced plastic. The reinforcing fibers embedded in the plastic can be arranged in a plurality of layers; for example, two fiber layers are aligned in the direction of the longitudinal extension of the rear insole 3 and at least one other fiber layer is arranged at a different angle, for example at a 45° angle to the longitudinal extension. The number of fiber layers can vary, especially decreasing towards the forefoot region, thereby increasing flexibility in the forefoot. The rear insole 3, which is thus formed as a particularly thin-walled shell with a material thickness of only about 1.8 mm, not only provides a particularly attractive appearance of the heeled shoe 100, but also the stability required for comfortable and secure wear.
The fibers in to reinforce the plastic can be industrially manufactured fibers, particularly carbon fibers. Natural fibers, such as flax, are particularly preferred. This choice particularly aligns with the desire for sustainability and improved biodegradability of new products.
As shown particularly in
For a firm connection between the rear insole 3 and the front insole 2, it is provided in the example shown that the two sole parts 2, 3 are arranged in an overlapping manner in the forefoot region 20, particularly in the front region 15 of the rear insole 3.
For an equally firm connection in the rearfoot region 22 of the rear insole 3, in particular, between the rear insole 3 and the heel 4, a plug connection 10 is provided, as illustrated, in particular, in
The pins 11a, 11b, 11c are arranged in a triangular configuration, which is particularly advantageous for the stability of the connection. In this context, all three pins have a round cross-section and are straight or cylindrical along their length, but they are angled relative to the upper side 19 of the rear insole 3. Therefore, while the pins 11a, 11b, 11c are inclined toward the rear end of the heeled shoe 100 concerning the upper side 19, they appear to stand essentially upright when considering the entire shoe 100, due to the inclination of the rear insole 3 towards the front insole 2. This allows for particularly easy insertion and assembly of the rear insole 3, especially the recesses 12a, 12b, 12c, and the pins 11a, 11b, 11c arranged therein, during manufacturing. To enhance the strength, the pins 11a, 11b, 11c are additionally adhesively bonded to the rear insole 3 within the recesses 12a, 12b, 12c. This creates a particularly strong connection between the rear insole 3 and the heel 4.
As shown particularly in
The cushioning element 9 is designed as a flat shock insert that corresponds in size and shape to the recess 16. In particular, the approximately 10 mm thick cushioning element 9 extends over most of the forefoot region 20, particularly over nearly the entire width and length of the front insole 2. To prevent slippage, the cushioning element 9 is fixed in the recess 16 by means of an adhesive. Additionally, the cushioning element 9 can also be adhesively bonded to the rear insole 3. The cushioning element 9 is made from a material softer than the front insole 2, allowing for a certain degree of front foot immersion during walking and the associated rolling motion of the foot.
It should be noted that in this example, in addition to the rear insole 3, all other components of the heeled shoe 100, such as the front insole 2, the heel 4, the footbed 5 and the shoe upper 6, can also be made from sustainable and biodegradable materials, particularly non-metallic materials. Thus, in this example, the heel 4, the front insole 2, and the cushioning element 9 are made from expanded thermoplastic polyurethane, or ETPU for short. The outsole 7 and the heel tip 8 are made of rubber, as usual.
It should be understood that the main claim is not limited to the example described above, but rather that the heeled shoe can be manufactured or designed in other configurations, not described.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10 2022 105 965.0 | Mar 2022 | DE | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/EP2023/055770 | 3/7/2023 | WO |
