MODULAR INSERT SYSTEM FOR SHOE SOLES

BACKGROUND

[0001]Shoe soles are designed not only to offer general support for the wearer's feet during walking or running but can also be engineered to provide varying degrees of support across different regions of the sole. For instance, the heel area, which absorbs the greatest impact forces, is often constructed with materials that offer superior cushioning. This variation in support can be achieved by modifying the mechanical properties of the sole material, such as its shape, thickness, density, hardness, and flexural characteristics. By tailoring these properties, manufacturers can produce soles that provide optimal support for a typical wearer's feet.

[0002]Given that gait characteristics differ significantly among individuals, footwear manufacturers typically design shoes to accommodate a broad spectrum of gait types based on an assumed norm. Additionally, shoes can be specially configured to suit various activities, from sprinting and long-distance running to playing specific sports like golf, tennis or fitness, or for casual wear. Even within running shoes, different sole configurations are needed for various distances and types of terrain. Consequently, wearers are often faced with a choice: opt for a versatile sole that may not be ideal for any specific activity or invest in multiple types of shoes tailored for different uses, such as road-running versus cross-country running.

[0003]Specialized soles are also available to address particular gait issues, such as overpronation or supination. Furthermore, some shoes come with soles customized for a specific combination of gait type, sport, or everyday use. Bespoke soles, tailored for an individual's unique foot structure, are an option but tend to be expensive. The primary focus of this invention is on a shoe that can be mass-produced and sold as commercial retail products.

[0004]It has been proposed to offer some level of customizability in foot support through orthotic insoles placed on top of a shoe's integral sole. These insoles may feature regions providing different levels of support, customized to the user's specific needs or gait type.

[0005]WO 2016092353 A1 from the same inventors as the present invention introduces a shoe where hard inserts are placed in cavities within the midsole. Though it does not address the issue of providing consistent and precise sensory-motor stimuli, it suggests a potential solution since the inserts are fitted from the top, with the cavity bottoms sealed by the outsole.

[0006]WO 2020058519 A1 from the same inventors as the present invention introduces an improved shoe compared to the shoe of WO 2016092353 A1, wherein the inserts are placed in the cavity from the outsole end and extend through the outsole to provide a ground contact surface. However, due to the flex of the shoe when rolling from the heel to the toes while walking, the inserts had not enough traction in the cavities and were falling out or rotated in the cavity. This issue compromised the stability and functionality of the shoe, and it could be prevented by gluing the inserts into the cavities. Unfortunately, this approach removes the opportunity to adjust or replace the inserts easily, thereby reducing their overall practicality and versatility.

[0007]EP 1352579 B1 describes a midsole with regions of varying hardness to suit a specific wearer. Once assembled, these portions can form a continuous mold, making further customization impossible, or remain as discrete components, which compromises the sole's mechanical integrity.

[0008]DE 20320091 U1 discusses an adaptable insert allowing limited customization of support in specific sole regions. This insert, introduced from the shoe's medial or lateral side and held by a clip, features vertical hexagonal holes for inserting pegs of varying hardness. This enables users to adjust the region's support level. However, the wide cavity needed for the insert diminishes the sole's overall mechanical integrity and provides a pathway for water and dirt intrusion. Moreover, the midsole material above and below the cavity, and the insert's material around the pegs, are prone to losing elasticity and resilience over time due to repeated compression, reducing the insert's effectiveness and shortening the shoe's lifespan.

SUMMARY

[0009]For gait-correcting inserts to be effective, they must maintain consistent proprioceptive feedback and remain securely in place. An insert that becomes loose, plastically compressed, or contaminated by dirt or water will alter the intended proprioceptive pressure, compromising its benefit.

[0010]It is therefore the object of the invention to eliminate the disadvantages of the prior art and to provide a shoe that provides consistent proprioceptive feedback to the user.

[0011]The object is achieved according to the invention with a shoe according to some embodiments. Some embodiments of the invention are given in the remainder of the specification and the claims.

[0012]The shoe according to some embodiments comprises a sole comprising a midsole part and an outsole part, each of the midsole part and the outsole part divided into a heel section, a midfoot section and a forefoot section. The midsole has an upper, foot-facing surface and the outsole part has a lower, ground-facing surface, and the outsole comprises a plurality of hollow cavities only in the heel section and the midfoot section. Each hollow cavity extends from the outsole along an axis which is substantially orthogonal to the lower ground-facing surface into the adjacent midsole to a depth of at least ⅔ of the midsole. The shoe further comprises a plurality of support adjustment elements constructed to be inserted into the hollow cavities and extending below the lower ground-facing surface of the outsole so as to adjust a support hardness of the midsole at the location of said each cavity. The outsole has a higher thickness in the forefoot section than in the heel section and in the midfoot section and each cavity comprises at least two elongated compression elements protruding from an inner surface of the hollow cavity towards a center of the hollow cavity.

[0013]In the context of this application, the term “midsole” refers to the part of the shoe that is located between the outsole and the user's foot.

[0014]In the context of this application, the term “outsole” refers to the part of the shoe that is located below the midsole and is in contact with the ground.

[0015]In the context of this application, the term “heel section” refers to a rear-most portion of the sole, extending from a posterior edge of the sole to a point beneath the midfoot.

[0016]In the context of this application, the term “midfoot section” refers to a central portion of the sole, positioned between the heel section and the forefoot section. This section typically corresponds to the area beneath the arch of the foot.

[0017]In the context of this application, the term “forefoot section” refers to a front portion of the sole, extending from the midfoot section to the anterior tip of the sole, corresponding to the area beneath the metatarsals and toes.

[0018]For a better understanding the support adjustment element may have three sections, where the first section is wholly inserted into the midsole, the second section is wholly inserted into the outsole and the third section is extending beyond the lower ground-facing surface of the outsole outwards.

[0019]The feature of support adjustment elements extending below the lower ground-facing surface of the outsole reduces the wear and tear of the outsole, as these support adjustment elements can be easily replaced when they become worn out. Additionally, the reduced thickness of the outsole in both the heel and midfoot section results in a level ground contact surface. This contrasts with traditional soles, which typically feature a positive drop, where the heel section is thicker than forefoot section. A level ground contact surface offers several advantages: it promotes natural walking or running experience, strengthens the natural positioning of the feed, reduces the wear and tear of specific sections of the outsole and reduces the risk of overpronation or supination.

[0020]Incorporating the compression element within the hollow cavity provides the benefit of securely holding the support adjustment elements in place during walking or running. At the same time, these support adjustment elements can be easily removed by the users to customize the hardness of the midsole according to their personal preferences, eliminating the need for a fitting session at a local running shop. Users can receive the shoe along with the support adjustment elements and configure it at home based on their knowledge or a gait analysis performed via video camera or at a local running shop. After setting up the shoe to their preferred specifications, users can later exchange the support adjustment elements for ones with different surface features but the same durometer. For instance, a user might configure the shoe for road running one day and, in preparation for a mountain trail run the next day, swap out the support adjustment elements for those designed to provide better traction. The same shoe can also be specifically configurated for playing sports like golf or tennis, depending on the configuration and the design of the support adjustment elements.

[0021]In a particular embodiment each support adjustment element is fixated in the hollow cavity with a press-fit mechanism.

[0022]The press-fit mechanism securely fixes the support adjustment elements in the hollow cavities during walking or running while allowing for easy removal by hand without the need for specialized tools. In contrast, prior art required the support adjustment elements to be glued into the cavity initially. Replacing a support adjustment element was challenging due to the risk of damaging the cavity and midsole if the process was not done correctly.

[0023]In some embodiments, the elongated compression element is line shaped.

[0024]It has been shown that a line shaped compression element is ideal for holding the support adjustment element in the cavity during walking or running but allows for replacing the support adjustment elements by hand. The line shaped compression element applies strong force along a narrow area, creating a strong, focused clamping force. This improves the fixation of the support adjustment element in the hollow cavity without needing uniform pressure across the entire surface of the support adjustment element. Additionally, the compression is concentrated along a line rather than across a broader area, the overall contact surface between the support adjustment element and the hollow cavity is reduced. This is beneficial, since less friction is needed for easy insertion or removal of the support adjustment element. The line shaped compression element can also absorb and distribute forces and thereby preventing movement or rattling of the support adjustment element inside the hollow cavity. Finally, the reduced contact area may make it easier to insert or remove the support adjustment element compared to full-surface compression, as less friction is involved.

[0025]The line shaped elongated compression element may extend from the top of the hollow cavity to the bottom of the hollow cavity in a vertical direction.

[0026]The line shaped elongated compression element may evenly extend into the hollow cavity with a distance between 0.5-0.8 mm.

[0027]In embodiments the line shaped elongated compression element is split into a lower part that is closer to the bottom of the cavity, a middle part and a upper part that is closer to the top of the hollow cavity, wherein only the middle part extends between 0.5-0.8 mm into the hollow cavity and the lower part and the upper part extends less than 0.5 mm into the hollow cavity. More preferably the lower part is the lower third of the line shaped elongated compression element and the upper part is the upper third of the line shaped elongated compression element.

[0028]The hollow cavity may comprise three or more elongated compression elements that are evenly distributed on the inner surface of the hollow cavity.

[0029]In some embodiments, the midsole has a first durometer, the outsole has a second durometer, and each support adjustment element has either a third durometer or a fourth durometer, wherein the second durometer is higher than the first durometer and the third durometer is equal or higher than the first durometer and the fourth durometer is higher than the second durometer.

[0030]Reducing the support adjustment elements to only two different durometers simplifies the customization process, whether done via video stream or by the user themselves, compared to using four or five different durometers as known from the prior art. Surprisingly, gait analysis conducted through video analysis has shown that support adjustment elements with two different durometers are sufficient to adequately configure the midsole's hardness for personal preferences. Implementing more support adjustment elements with additional durometers only marginally increases the degree of foot support provided by the midsole.

[0031]As mentioned before, the support adjustment element has preferably three sections, wherein only the durometer of the first section, which is wholly inserted into the midsole, is relevant for adjusting the support hardness of the midsole. Therefore, the third and fourth durometer of the support adjustment element refer to the durometer of the first section of said support adjustment element.

[0032]In embodiments, the midsole has a durometer of 45-60 Shore, the outsole has a durometer of 60-70 Shore and each support adjustment element has a durometer of either 50-70 Shore or 80-95 Shore. In embodiments, the midsole has a durometer of 53-57 Shore, the outsole has a durometer of 60-66 Shore and each support adjustment element has a durometer of either 55-65 Shore or 85-95 Shore.

[0033]The combination of these four durometers has been shown to provide the best proprioception for a user.

[0034]In embodiments, the second section of the support adjustment element, which is in contact with the outsole has the same durometer as the outsole and the third section of the support adjustment element, which is extending beyond the lower ground-facing surface of the outsole outwards, has the same durometer or a higher durometer then the outsole, which improves the durability of the outsole.

[0035]In some embodiments, the outsole comprises at least one of filled cavity in the forefoot section, extending along the axis which is substantially orthogonal to the lower ground-facing surface into the midsole.

[0036]In embodiments, the filled cavity extends to at least half the depth of the midsole.

[0037]Due to the natural rolling movement when walking—where the heel section contacts the ground first, followed by the midfoot and then the forefoot—the forefoot section is usually more flexible to facilitate a dynamic push-off during walking or running. However, this flexibility in the forefoot section can create several issues. One significant problem is that a hollow cavity in the forefoot section can become excessively deformed during the push-off phase, destabilizing the support adjustment element located in the cavity. This deformation can reduce the midsole's hardness in the forefoot section, thereby diminishing the overall support for the foot. Additionally, the deformation of the hollow cavity in the forefoot might lead to the loss of the support adjustment element during walking or running, completely eliminating the support in this region.

[0038]This disadvantage in the prior art is overcome by implementing at least one filled cavity in the forefoot section of the sole. This filled cavity ensures the adjustment of the midsole's support hardness in the forefoot without the risk of damaging a hollow cavity or losing the inserted support adjustment element due to the forefoot's flexibility.

[0039]In embodiments, the filled cavity is an integral part of the outsole, extending into the midsole and filled with the same material as the outsole. This design is easier to manufacture and provides adequate support hardness in the forefoot section at a reasonable production cost.

[0040]In another embodiment, the filled cavity is also an integral part of the outsole extending into the midsole, but it is filled with a different material from that of the outsole. Preferably, the material in the filled cavity has a higher durometer than the outsole. Although this embodiment is more challenging to manufacture, it allows for increased support hardness in specific regions of the midsole, enabling a more precise and balanced hardness adjustment.

[0041]In embodiments, the filled cavity extends below the lower ground-facing surface of the outsole. The ground contact surface of a shoe has typically two different regions, where the wear and tear are increased - the heel section and the fore-foot section. This is mainly due to the fact that during walking or running the heel section makes first contact with the ground, supporting all the weight of the user in a very limited area, which increases the wear and tear. The same is true for the forefoot section which makes last contact with the ground and remains in contact until the user pushed the foot of the ground. Also, in the forefoot section the wear and tear is increased compared to the midfoot section. In an embodiment where the filled cavity in the forefoot section extends below the lower ground-facing surface of the outsole, the initial wear and tear appears on the filled cavity and not on the outsole in the forefoot section. This improves the longevity of the shoe since the wear and tear of the outsole in the forefoot section is reduced.

[0042]In embodiments, the filled cavity extends below the lower ground-facing surface of the outsole. A sole ground contact surface typically experiences increased wear and tear in two key regions: the heel section and the forefoot section. This is primarily because, during walking or running, the heel section makes initial contact with the ground, bearing the user's full weight over a limited area, which accelerates wear. Similarly, the forefoot section experiences high wear and tear as it makes the final ground contact and remains in contact until the foot pushes off.

[0043]By extending the filled cavity below the lower ground-facing surface of the outsole in the forefoot section, the initial wear occurs on the filled cavity rather than on the outsole itself. This design improves the soles longevity by reducing wear and tear on the outsole in the forefoot section.

[0044]The filled cavity may extend up to 5 mm, and/or up to 8 mm beyond the lower ground-facing surface of the outsole outwards.

[0045]In some embodiments, where the filled cavity in the forefoot section extends below the ground-facing surface, the filled cavity bears the initial wear and tear, thereby protecting the outsole. This configuration enhances the overall durability of the shoe by mitigating the wear and tear typically concentrated in the forefoot section.

[0046]In an embodiment, the shape of each filled cavity which extends below the lower ground-facing surface of the outsole is a segment of a sphere or an ellipsoid.

[0047]It has surprisingly been shown that the shape of a sphere or an ellipsoid improves the durability of the outsole of the shoe and provides an increased proprioception to the user compared to other shapes.

[0048]Each support adjustment element may comprise a ground contact surface that is tilted towards the midline of the sole. This tilted ground contact surface enhances foot stability during walking, as it encourages the foot to tilt towards the midline of the sole rather than outwards, thereby reducing the risk of ankle rolling and improving overall gait alignment.

[0049]In an embodiment, each support adjustment element comprises an anti-rotation-element with a stop section and the cavity comprises a recessed part with a counter-stop section, which interacts with the stop section of the anti-rotation-element to prevent rotation of the support adjustment element in the cavity.

[0050]The anti-rotation element enhances the stability of the support adjustment element within the hollow cavity, thereby improving the overall consistency of the midsole's support hardness. This stability is even more beneficial when combined with the tilted ground contact surface of the support adjustment element, as it prevents the element from rotating. Consequently, the tilted ground contact surface remains consistently oriented towards the midline of the foot, ensuring optimal foot alignment and stability during movement.

[0051]The stop section of the anti-rotation-element may have a shape of a rounded square.

[0052]In the context of the invention the term “rounded square” refers to a square with rounded edges.

[0053]The anti-rotation element, which features a rounded square shape, offers the advantage of making the support adjustment element easy to remove and install within the hollow cavity. The rounded corners facilitate the installation process by guiding the support adjustment element into the correct position, even if the stop section of the element is not perfectly aligned with the counter-stop section of the hollow cavity initially. Furthermore, the rounded corners significantly reduce peak shear forces and thereby improves the proprioceptive feedback to the user.

BRIEF DESCRIPTION OF THE DRAWINGS

[0054]The invention is explained in greater detail in the following on the basis of some exemplary embodiments represented in the figures. If alternative embodiments differ only in individual features, the same reference signs have been used in each case for the features that remain the same. In the figures, which are each merely schematic:

[0055]FIG. 1 shows an embodiment of a shoe from the side

[0056]FIGS. 2a and 2b show an embodiment of a shoe sole from the bottom view and an embodiment of a support adjustment element

[0057]FIGS. 3a, 3b, and 3c show an embodiment of a shoe with different configurations of support adjustment elements

[0058]FIGS. 4a and 4b show an embodiment of an outsole from a perspective top view and a perspective bottom view

[0059]FIGS. 5a, 5b, and 5c show different embodiments of a hollow cavity.

DETAILED DESCRIPTION

[0060]FIG. 1 shows an embodiment of a shoe 1 with a sole 3 comprising a midsole 5 and an outsole 7 located below the midsole 5 to protect the midsole 5 from wear and tear while walking or running.

[0061]FIGS. 2a and 2b show an embodiment of the sole 3 and a support adjustment element 9. The sole 3, comprising from a rear end 11 to a front end 13 in a sequential order a heel section 15, a midfoot section 17 adjacent to the heel section 15 and a forefoot section 19 adjacent to the midfoot section 17. The heel section 15 is located under the heel of a user's foot, while wearing. The midfoot section 17 is located under the arch of the foot of a user's foot, while wearing. The forefoot section 19 is located under the ball of the foot and the toes of the user, while wearing. The heel section 15 and the midfoot section 17 comprise a plurality of hollow cavities 21 extending from the outsole 7 along an axis which is substantially orthogonal to the lower ground-facing surface of the outsole 7 into the midsole 5, to a depth of at least ⅔ of the midsole 5. The hollow cavities 21 are located on the medial side of the sole 3 (medial cavities 21a) and on the lateral side of the sole 3 (lateral cavities 21b). Each hollow cavity 21 has a cylindrical part 23 that extends into the midsole 5 to wholly fit a cylindrically formed first section 25 of the support adjustment element 9. Each hollow cavity 21 further comprises a recessed part 27 with a counter-stop section 29 to interact with a second section 31 of the support adjustment element 9. The second section 31 comprises an anti-rotation-element 33 with a stop section 35. The support adjustment element 9 further comprises a third section 37, which when the support adjustment element 9 is inserted into the hollow cavity 21 extends beyond the ground facing surface of the outsole 7. This third section 37 of the support adjustment element 9 can comprise a tilted ground contact surface 39, wherein a part 41 that is facing the outside of the sole 3 is thicker than a part 43 that is facing the midline of the sole 3. The sole 3 further comprises in the forefoot section 19 a plurality of filled cavities 45. Each filled cavity 45 extends beyond the ground facing surface of the outsole 7 such that the shoe 1 contacts the ground in the forefoot section 19 with the filled cavities 45 until they are worn down and the outsole 7 has in the forefoot section 19 an even surface. Each filled cavity 45 can also independently extend into the midsole 5 at least to a depth of half of the midsole.

[0062]FIGS. 3a-3c show three different configurations of support adjustment elements 9. In FIG. 3a, the medial hollow cavities 21a and the lateral hollow cavities 21b are filled with support adjustment elements 9a having a durometer of 55-65 Shore (light grey) to support a user having a pronating foot-foot rolls optimally during walking or running. In FIG. 3b, the medial hollow cavities 21a are filled with support adjustment elements 9b having a durometer of 85-90 Shore (dark gray) and the lateral hollow cavities 21b are filled with support adjustment elements 9a having a durometer of 55-65 Shore (light grey) to support a user that suffers from an overpronating foot-foot rolls excessively inward during walking or running, beyond the normal range of pronation. In FIG. 3c, the medial hollow cavities 21a are filled with support adjustment elements 9a having a durometer of 55-65 Shore (light gray) and the lateral hollow cavities 21b are filled with support adjustment elements 9b having a durometer of 85-90 Shore (dark grey) to support a user that suffers from a supinating foot-foot rolls outwards during walking or running.

[0063]FIGS. 4a and 4b show an outsole 7 from the side top view and FIG. 4b shows an outsole 7 from the side bottom view. The outsole 7 has a reduced thickness in the heel section 15 and the midfoot section 17 compared to the forefoot section 19. This ensures that the ground contact surface of the outsole 7 is planar, if support adjustment elements (not shown) are inserted into the hollow cavities 21. The outsole 7 further comprises a plurality of filled cavities 45, which extend beyond the ground contact surface of the outsole 7 but only a single filled cavity 45a extends into the midsole 5 to contribute to the support of the midsole 5.

[0064]FIGS. 5a-5C show detailed views of a hollow cavity 21 comprising the cylindrical part 23 and the recessed part 27 with the counter-stop section 29. The cylindrical part 23 comprises three (FIG. 5a), four (FIG. 5b) or five (FIG. 5c) line-shaped elongated compression elements 47 that located on the surface of the cylindrical part 23 and extending into the hollow cavity 21. Also an embodiment with only two or more than five line-shaped elongated compression elements 47 in the hollow cavity 21 is possible. The compression elements 47 are evenly distributed on the surface of the cylindrical part 23 and are configured to interact with the first section 25 of the support adjustment element 9 (see FIG. 2b) to form a press-fit mechanism to fixate the adjustment element 9 in the hollow cavity 21.