Classifications

• • A—HUMAN NECESSITIES
  • A43—FOOTWEAR
  • A43B—CHARACTERISTIC FEATURES OF FOOTWEAR; PARTS OF FOOTWEAR
  • A43B13/00—Soles; Sole-and-heel integral units
  • A43B13/14—Soles; Sole-and-heel integral units characterised by the constructive form
  • A43B13/18—Resilient soles
  • A43B13/181—Resiliency achieved by the structure of the sole
  • A43B13/186—Differential cushioning region, e.g. cushioning located under the ball of the foot
• • A—HUMAN NECESSITIES
  • A43—FOOTWEAR
  • A43B—CHARACTERISTIC FEATURES OF FOOTWEAR; PARTS OF FOOTWEAR
  • A43B13/00—Soles; Sole-and-heel integral units
  • A43B13/02—Soles; Sole-and-heel integral units characterised by the material
  • A43B13/04—Plastics, rubber or vulcanised fibre
• • A—HUMAN NECESSITIES
  • A43—FOOTWEAR
  • A43B—CHARACTERISTIC FEATURES OF FOOTWEAR; PARTS OF FOOTWEAR
  • A43B13/00—Soles; Sole-and-heel integral units
  • A43B13/14—Soles; Sole-and-heel integral units characterised by the constructive form
  • A43B13/141—Soles; Sole-and-heel integral units characterised by the constructive form with a part of the sole being flexible, e.g. permitting articulation or torsion
• • A—HUMAN NECESSITIES
  • A43—FOOTWEAR
  • A43B—CHARACTERISTIC FEATURES OF FOOTWEAR; PARTS OF FOOTWEAR
  • A43B13/00—Soles; Sole-and-heel integral units
  • A43B13/14—Soles; Sole-and-heel integral units characterised by the constructive form
  • A43B13/18—Resilient soles
  • A43B13/181—Resiliency achieved by the structure of the sole
• • A—HUMAN NECESSITIES
  • A43—FOOTWEAR
  • A43B—CHARACTERISTIC FEATURES OF FOOTWEAR; PARTS OF FOOTWEAR
  • A43B13/00—Soles; Sole-and-heel integral units
  • A43B13/14—Soles; Sole-and-heel integral units characterised by the constructive form
  • A43B13/18—Resilient soles
  • A43B13/181—Resiliency achieved by the structure of the sole
  • A43B13/185—Elasticated plates sandwiched between two interlocking components, e.g. thrustors
• • A—HUMAN NECESSITIES
  • A43—FOOTWEAR
  • A43B—CHARACTERISTIC FEATURES OF FOOTWEAR; PARTS OF FOOTWEAR
  • A43B13/00—Soles; Sole-and-heel integral units
  • A43B13/14—Soles; Sole-and-heel integral units characterised by the constructive form
  • A43B13/18—Resilient soles
  • A43B13/187—Resiliency achieved by the features of the material, e.g. foam, non liquid materials
• • A—HUMAN NECESSITIES
  • A43—FOOTWEAR
  • A43B—CHARACTERISTIC FEATURES OF FOOTWEAR; PARTS OF FOOTWEAR
  • A43B13/00—Soles; Sole-and-heel integral units
  • A43B13/14—Soles; Sole-and-heel integral units characterised by the constructive form
  • A43B13/18—Resilient soles
  • A43B13/187—Resiliency achieved by the features of the material, e.g. foam, non liquid materials
  • A43B13/188—Differential cushioning regions
• • A—HUMAN NECESSITIES
  • A43—FOOTWEAR
  • A43B—CHARACTERISTIC FEATURES OF FOOTWEAR; PARTS OF FOOTWEAR
  • A43B13/00—Soles; Sole-and-heel integral units
  • A43B13/14—Soles; Sole-and-heel integral units characterised by the constructive form
  • A43B13/22—Soles made slip-preventing or wear-resisting, e.g. by impregnation or spreading a wear-resisting layer
  • A43B13/223—Profiled soles
  • A43B13/226—Profiled soles the profile being made in the foot facing surface

Definitions

• This Invention applies to semi-finished products and connected technologies used in the production of footwear; more precisely, this Invention describes the shoe lower portion in contact with the ground called sole, also called outer sole.
• Footwear is a highly diversified leather goods item in terms of shape, use and declination.
• Footwear that can be classified in the third category above therefore has a design origin that always remains attentive to technical performance such as comfort, correct support for the foot during walking, a high breathability factor and gas exchange between the inside and outside, use of materials with antifungal and germicidal characteristics, improved flexibility, etc.
• Footwear in the third category above such as those intended for competitive use, mainly uses cutting-edge material technologies and construction processes that are optimized for large production quantities and, as already highlighted in paragraph 002, point c), can share some technical refinements deriving from competitive use for the benefit of the general user.
• a shoe can be separated into some macro-parts, for example:
• the soles thus constructed are mainly the result of manufacturing processes through injection and molding of synthetic materials, which can combine unique elasticity and resilience factors that cannot be reproduced with natural materials, such as leather and its derivatives.
• EVA Polyurethane
• PVC Polyurethane
• EVA Ethylene Vinyl Acetate
• PVC Polyurethane
• EVA Ethylene Vinyl Acetate
• EVA is a cross-linkable polymer which, when subjected to an adequate temperature inside a mould, expands and produces an extremely light, flexible semi-finished product with no shape memory.
• EVA is not easily recyclable, except in its inert filler added to another material, Thermoplastic Polyurethane can instead be reused through fusion and moulding, thus proving extremely advantageous.
• Nike's patent US2022248804A1 describes, for example, a sole in synthetic material in which a peculiar cushioning element, called a "barrier layer”, is inserted and incorporated inside a closed volume, also filled with liquids or gases.
• This cushioning element is located in the central/front area of the sole and manages the pressure forces coming from the foot.
• the sole constructed in this way, presents unquestionably great advantages but also a significant complexity in the construction process.
• Patent WO2016191109A1 describes a sole in which an elastic layer is worked inside through openings created in various sizes and dimensions, in order to modify the elastic effect of the aforementioned layer. This is an interesting but extremely complicated solution, since synthetic soles are generally produced by injection and mould, thus forcing the inventive process within the technical limits of a layout that allows easy extraction of the sole from the mould.
• Reebok's patent US7966749B2 describes an element that can be inserted inside a sole, composed of two closed chambers connected by a corrugated channel. The presence of air inside the two chambers, air that can pass from the first chamber to the second and vice versa, creates a shock-absorbing element. Again, this is a highly efficient but extremely complicated system.
• Adidas's patent US9930928B2 describes a sole that includes two regions of space in which two types of materials are used, a first type of expanded materials that are free to move, and a second region of more compact materials that penetrates the first region causing it to block, thus creating a controlled shock-absorbing effect.
• the described solution is once again extremely complex and limits the cost-effectiveness of the Invention.
• Newton Running Company publication WO2023122761A1 describes a sole in which there are two layers facing each other. The two layers are worked using sinusoidal undulations and are coupled by the interposition of a membrane. The presence of a compressive force causes the two layers to penetrate and the membrane creates a progressive resistance, storing the energy that will be released to the foot as a rebound force, opposed to the compression force. This solution is highly functional but has construction complications and economic inefficiency.
• Mizuno's publication US2020305541A1 describes a sole made up of different layers, therefore different coupled soles.
• a first sole has a plurality of protrusions on the side in contact with the foot
• the outer sole has a plurality of protrusions on the surface in contact with the ground
• an intermediate sole between the two has a great rigidity.
• the combination of the protrusions between the layers of the different soles creates a shock-absorbing effect.
• This solution is complex and furthermore is proven to create a floating effect during walking that is not always pleasant, and for this reason this solution can be improved.
• New Balance Patent US6026593 describes a shock-absorbing element designed to be inserted into the sole of a shoe.
• the shock-absorbing element consists of several closed tubular elements. This solution can trigger an evident floating effect and presents a certain structural complexity.
• the Invention describes a shoe sole featuring a non-linear shock-absorbing feature and a unique rebound effect, favoring a layout designed for weight maximum containment and maximum ease of use.
• the embodiment of the Invention is designed a sole for footwear in synthetic material, obtained by the already known injection processes on a mould.
• the Sole can also be made by a casting technique on a mould, when deemed feasible and consistent with additional factors, even of a non-technological nature.
• the synthetic material that constitutes the sole can be chosen from those already known in the State of the Art, for example EVA (Ethylene Vinyl Acetate), Polyurethane (PU), TR etc.: the choice will depend on the quantity of the desired shock-absorbing effect, an effect that will then be modulated by the peculiar shape of the sole as disclosed in this text.
• EVA Ethylene Vinyl Acetate
• PU Polyurethane
• TR etc. the choice will depend on the quantity of the desired shock-absorbing effect, an effect that will then be modulated by the peculiar shape of the sole as disclosed in this text.
• the specific processes that provide the Sole with an improved shock-absorbing effect and an improved "rebound" effect - i.e. a rebound effect - are applicable to any sole produced by injection/mould or casting/mould; for this reason, in the drawing table, the aesthetics of the sole shown therein can conveniently be modified according to production needs.
• the Sole presents a differentiation of its structure in the central area (10a) compared to the peripheral area (11a).
• Fig.1a shows how the cross-section profile of the sole (Z-Z') equipped with its tread (15a) which rises peripherally with a wall along a vertical axis (14a) up to its upper outer edge (12a) to descend again (13a) until it meets a central area (10a).
• the central area of the sole is the one that is most subjected to the downward thrust given by the foot, and is the one involved in producing the shock-absorbing functions during walking.
• the central area of the sole is equipped with an intrinsic elasticity characteristic deriving from the materials of which the Sole is made, as described in paragraph 0044.
• the use of elastic materials for the manufacturing of footwear soles can create an unwanted phenomenon during walking, namely a floating effect that makes the sensation of the positioning of the foot on the ground uncertain.
• the said floating effect if can be sought to increase the degree of comfort of the shoe, namely the ability to absorb shocks during walking, however it does not make it possible to perceive the ground as a stable reference on which to operate the necessary thrusts and movements of the foot for walking, running or practicing sports.
• the floating effect can therefore create disorientation, precarious balance; in general it occurs on all those footwear equipped with a high shock-absorbing effect of the sole.
• the area subjected to a thrust towards the ground is smaller than the area that is created when the foot is parallel to the ground, so the deformation that the sole undergoes is decidedly higher.
• the same reasoning can be applied to the thrust that the forefoot generates during walking towards the sole in its apical part.
• a continuous perimetral crack is appropriately designed on the internal perimeter of the sole (16a) whose effect is to separate the central area thus formed (10a) from the peripheral area (12a, 13a, 14a), i.e. the area composed of the elevation of the tread along the vertical axis, its edge and the descending profile, keeping the two areas mutually united thanks to the lower portion of the sole, i.e. that of the tread (15a).
• the central area of the sole (10b) can conveniently be added in a subsequent processing phase to the tread area (11b) as disclosed in Fig.1b , while respecting the construction criteria of the present Invention as declared in 0051, i.e. the central area of the sole is separated from the peripheral area (12b, 13b, 14b) by the presence of the perimetral cracking.
• the creation of a central area of the sole not in contact with the edge of the same amplifies the effect of softness and elasticity during walking, as the yielding of this area of the sole is enhanced by its own deformation, a deformation that develops freely along the empty space created by the perimetral cracking.
• the elasticity characteristic is defined as "enhanced” and has not a linear character, since once the area of the perimetral crack (30) has been filled by the application of the vertical forces that develop during walking (33), the material forming part of the central area of the sole comes into contact with the edge of the sole (31,32) which stops its expansion and deprives the sole of the floating effect, limiting its elasticity, triggering a non-linear damping phenomenon.
• the non-linearity of the enhanced elasticity factor depends on the width of the perimeter crack, however - as disclosed in paragraphs 0050, 0051 and 0052 - the progression of the thrust forces generated by walking and the areas subjected to such stresses are not constant; for this reason, the perimetral crack of the sole will also be advantageously designed with variable widths depending on its development along the internal perimeter of the sole.
• variable thickness of the perimeter cracking is provided here:
• the central area of the sole (10a) can be further processed by creating transverse slots, of variable section and variable length.
• Fig.2 shows an example of the quantities of the groups of slots that can be made in the central area of the sole, namely:
• the slot groups allow to adapt the variety of material used for the construction of the sole to the various applications in the types of footwear. In fact it is possible to increase the degree of the enhanced elasticity of the material of which the sole is made by making the slots disclosed in paragraph 0062, while maintaining a high damping factor resulting from the contact of the internal area of the sole with the respective edge.
• Fig.5 shows a longitudinal section of the Sole with an example of the cracking groups (50) described in paragraph 0062.
• the Sole is preferably constructed by injecting synthetic materials into moulds, more precisely by injection or even casting. It is well known that the production of moulds is very expensive, so a shoe soles manufacturing company is interested in optimising the production processes also with regards the economic parameters; it is therefore obvious that using a single material is more economically advantageous.
• the Sole according to the idea of the Invention can be produced, with the same material used, with different elasticity characteristics and different damping characteristics, thanks to the perimetral cracking and the transversal cracking groups in the central area of the sole. Furthermore, as regards the presence of transverse crack groups in the central area of the sole, it is also possible to implement single cracks, or even in some cases a single crack forming part of a single group, appropriately positioned.
• a technology is devised that, applied to the Sole, allows to modify the "rebound" characteristics, i.e. the rebound of the elastic element inherent in the material used for the construction of the sole, but also to modify the overall behaviour of the sole when used for walking, running, jumping, etc.
• the developed technology avoids to produce "n” moulds for "n” elasticity and rebound characteristics, but to adapt a limited number of models of the Sole - models differentiated by quantity of crack groups or width of perimetral cracking - to additional characteristics. Furthermore, this technique according to the idea of the Invention allows to reduce the variety of synthetic materials used for the creation of the Sole, as it is possible to limit or increase the elasticity and rebound characteristics of a single material.
• an elastic device in metal, for example in harmonic steel, or synthetic material without shape memory, for example carbon or composite material, and said elastic device is inserted into the spaces created by the perimetral cracking as per this Invention.
• the elastic device (64) has a "C" shape, or the shape of a staple, as can be seen from the cross-section of the sole in Fig.6 (60) in which the vertices of the sections folded at 90° (61) of the elastic device have a further 180° torsion to form a hook (62) such as to cause a thickening of the apical section.
• the dimensions of the elastic devices allow them to be inserted into the internal edges of the perimetral crack in a transverse position, so as to overlap the central part of the sole (63) and therefore create an additional support surface for the foot, a surface which will react to the vertical forces generated by walking, with a rebound effect enhanced by the presence of the elastic devices.
• the quantity of elastic devices that can be inserted on the sole depends on the quantity of rebound that one wishes to obtain; the elastic devices are in fact designed with no mechanical memory, so that once subjected to vertical forces coming from walking, they flex and react with an upward thrust, which is added to that of the material of which the Sole is made.
• the hook in the apical area of the 90° folded section of the elastic device fits tightly into the perimetral cracking, allowing its stability in contact with the sole during the construction phases of the sole itself.
• the elastic devices do not influence the non-linear damping factor of the enhanced elasticity of the sole, since they limit the volume of the perimeter crack in a negligible way; surprisingly, however, they increase said characteristics since the aforementioned devices have limited bending capacity along the area of the section bent at 90°, or they bring higher rigidity to the material in the section of the sole external to the perimetral cracking.
• the elastic devices inserted in the sole to improve the rebound effect, or the bounce can highlight the section that rests on the horizontal surface of the central area of the sole - the one delimited by the perimeter crack - with appropriate different shapes, deriving from the need to increase or decrease the rebound effect.
• asymmetric shapes 70a, 71a
• both the perimetral cracking and those in groups in the central area of the sole provide a well-defined internal volume that can be filled, totally or partially, with dilating elastomeric polymers or with a material which tends to be fluid and in which the speed of the applied forces immediately stiffens the structure, changing its fluid state into a solid/semi-solid state.
• transverse crack groups can be used to provide additional technical performance to the sole thanks to the provision of a device designed to be inserted inside them.
• an elastic buffer element without shape memory (100) constructed from a sheet of synthetic or metallic material, in the shape of a double ogive with two concave and opposite lateral walls (101,102) generating an internal opening (103).
• the elastic buffer element In the presence of compressive forces orthogonal to the two facing walls (104) the elastic buffer element has the capacity to compress (105) and therefore to exert a contrary repulsive force (106).
• the elastic buffer elements are inserted inside one or more slots of the transverse slot group in such a way as to present their lateral walls in contact with the lateral walls of the slots (112).
• the elastic buffer elements are subjected to a cyclic compression generated by the walking movement, as the transverse slot groups will tend to cyclically close and open (91) due to the flexion of the sole. The forces that will be discharged on the elastic buffer elements will therefore be more or less contrasted by them.
• the elastic buffer elements it is also possible - when required - to make the elastic buffer elements with an adequate height "h” (110), or a height less than the depth "h1" (111) of the cracks of the transversal cracking group of the sole, in order not to compromise the compression of the aforementioned area during walking.
• This Invention is applicable in any type of footwear, even in models not designed for a specific and highly specialized sporting activity, for the manufacturing of synthetic soles with improved comfort characteristics.
• NPL1 none.

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• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Materials Engineering (AREA)
• Footwear And Its Accessory, Manufacturing Method And Apparatuses (AREA)

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Citations (11)

• 2025
  • 2025-04-15 EP EP25170527.3A patent/EP4640102A1/de active Pending
  • 2025-04-18 US US19/183,529 patent/US20250325071A1/en active Pending
  • 2025-04-22 CN CN202510505218.0A patent/CN120827240A/zh active Pending

Patent Citations (11)

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