Reinforcement Element for a Sports Shoe

This application claims priority of French patent application No. FR2403600 of Apr. 8, 2024, the content of which is hereby incorporated by reference herein in its entirety.

The invention relates to a reinforcement element for a sole of a sports shoe. The invention also relates to a sports shoe, in particular to a sports shoe suitable for trail running, comprising such a reinforcement element.

Trail running is a sport which consists in following a trail in the natural environment by running or walking. Enthusiasts thus have to run or walk on paths which are uneven and/or slippery and/or go uphill or downhill. The paths can be, for example, mountain tracks over which stones, roots, snow or even sand are scattered. Trail running can even be done off the paths. Doing this sport requires not only suitable stamina levels for running but also a high degree of agility in order to run over this uneven terrain effectively without being injured.

Trail running thus requires the use of specific shoes which not only are suitable for running but also have the following properties:

The trail running shoes known in the prior art do not satisfy all these properties. It is thus desirable to make improvements to the existing sports shoes.

The object of the invention is to provide a trail running shoe which simultaneously is hard-wearing, effectively absorbs shocks, is stable and light and effectively transmits propulsion drive from their users.

The invention relates to a sole for a sports shoe comprising a reinforcement element, the reinforcement element being intended to extend below the plantar aponeurosis, the reinforcement element comprising a rear part, a front part and a central hinge connecting the front part to the rear part, the front part being less rigid than the rear part, the rear part being intended to extend in front of a posterior contact point of the foot, the front part comprising at least one longitudinal branch, the at least one longitudinal branch being intended to extend between an anteromedial contact point and an anterolateral contact point of the foot.

The at least one longitudinal branch can comprise a first longitudinal branch and a second longitudinal branch extending parallel to the first longitudinal branch.

The first longitudinal branch can have a substantially constant width and thickness, and/or the second longitudinal branch can have a substantially constant width and thickness.

The first longitudinal branch can comprise a substantially straight inner lateral edge and a substantially straight outer lateral edge and/or the second longitudinal branch can comprise a substantially straight inner lateral edge and a substantially straight outer lateral edge.

The rear part of the reinforcement element can be intended to extend below a navicular bone, below a cuboid bone, below cuneiform bones, and below a rear part of the five metatarsals of a foot, and the at least one longitudinal branch is intended to extend below a front part of the second metatarsal and/or below a front part of the third metatarsal.

The rear part of the reinforcement element can comprise a set of openings with a closed contour.

The rear part of the reinforcement element can comprise a set of stiffening ribs, the stiffening ribs extending so that they project, in particular downwards, relative to a plane within which the rear part extends.

The said stiffening ribs can be arranged on the closed contour of the said openings.

The rear part of the reinforcement element can comprise an inner lateral rim extending upwards and intended to extend along an inner lateral edge of the plantar aponeurosis, and/or the rear part of the reinforcement element can comprise an outer lateral rim extending upwards and intended to extend along an outer lateral edge of the plantar aponeurosis.

The rear part of the reinforcement element can comprise a rear notch configured so as to space the posterior contact point apart from a rear edge of the reinforcement element by at least one centimetre.

The central hinge can form a narrowest zone of the reinforcement element along a transverse axis.

The reinforcement element can be a monolithic element consisting of plastic and obtained by moulding.

The sole can comprise an upper part provided with an upper surface intended to receive a lower surface of a foot, the upper part comprising an upper shock-absorbing layer, the upper part extending above the reinforcement element.

The sole can comprise a lower part provided with a lower surface intended to come into contact with the ground, the lower part comprising a lower shock-absorbing layer, the lower part extending bellow the reinforcement element.

The reinforcement element can comprise a visible inner face on an inner side of the sole and/or a visible outer face on an outer side of the sole.

The invention also relates to a sports shoe, in particular a sports shoe suitable for running, preferably trail running, comprising a sole as defined above.

illustrate, in exploded views, a sports shoesuitable for running, in particular trail running. The sports shoemainly comprises a soleand an upper. The solerefers to the part of the shoewhich extends between the lower surface of a foot and the ground that the shoe strikes. The upperrefers to the part of the shoewhich extends around and over the top of the foot. The upperis shown schematically in. The uppercomprises in particular an upper opening for inserting the foot into the shoe, a tongue and tightening means, for example laces, for tightening the upper around the user's foot. The uppercan be made, for example, from fabric. It can comprise one or more pieces of fabric assembled together and may be provided with reinforcement elements. The upperis fixed, for example sewn or glued, to the sole.

The shoeillustrated in the figures is a shoe for a right foot. The invention can of course also be applied to a left shoe and for any size of shoe. It is assumed that the shoe is lying on a horizontal piece of ground by way of its sole. The longitudinal axis X refers to the horizontal axis oriented from the rear to the front of the shoe, in other words from the heel to the toes. The transverse axis Y refers to the horizontal axis, perpendicular to the longitudinal axis X, oriented from left to right, left and right being defined according to the point of view of the user of the shoewhen they are looking straight in front of them. The vertical axis Z refers to the axis perpendicular to the longitudinal axis X and to the transverse axis Y. The vertical axis Z is oriented from bottom to top. In the following description, the terms “lower” and “upper” characterize an arrangement according to the vertical axis Z. The terms “inner” and “outer” characterize an arrangement according to the transverse axis Y: the inner side of the shoe refers to the side of the shoe facing the user's other foot. The outer side of the shoe refers to the side of the shoe opposite the inner side. In the case of a right shoe, the inner side hence relates to the left-hand side of the shoe and the outer side relates to the right-hand side of the shoe.

As can be seen in, the solecomprises, within a longitudinal and vertical plane, a lower surface with a convex shape to promote the satisfactory rolling forward of the foot when running. In particular, a rear partand a front partof the sole each comprise an arc-shaped lower surface, a centre of the arc being positioned above the ground. The rear partand the front partare connected by an intermediate part, the lower surface of which is substantially horizontal. The thickness of the solealong the vertical axis Z can decrease roughly moving from the rear to the front of the sole.

With reference to, the solecomprises a plurality of superposed layers. The solecomprises in particular an upper partprovided with an upper surfacein contact with the upper and/or directly with the lower surface of a foot, a lower partprovided with a lower surfacein contact with the ground, and a reinforcement elementinterposed between the upper partand the lower part. The lower partcomprises a lower shock-absorbing layerand a wear layerarranged underneath the lower shock-absorbing layer.

The wear layeradvantageously comprises a set of gripping lugsallowing the sole to grip on uneven terrain such as rocks, sand or snow. The wear layercan, for example, be made from rubber, or alternatively from polyurethane (PU). The wear layeralso comprises a toe bumperarranged at its front end. The toe bumperis a substantially vertical part of the outsole, protecting the toes from frontal impacts.

The upper partcomprises an upper shock-absorbing layer. The lower shock-absorbing layerand the upper shock-absorbing layercan consist of a shock-absorbing synthetic polymer such as a foam. For example, the lower shock-absorbing layerand the upper shock-absorbing layercan be made from ethylene vinyl acetate (EVA) and/or from polyurethane (PU). The upper shock-absorbing layermay also comprise an insole intended to come into direct contact with a foot (or of course with a sock pulled over a foot).

The reinforcement elementis embedded in the sole, and the majority of it is therefore invisible from outside the shoe. The inner and outer lateral edges of the reinforcement element can nevertheless be visible respectively on the inner and outer sides of the sole. The reinforcement element can therefore comprise visible outer faces,on the inner and outer sides of the sole. The outer facecan be seen particularly well in. Advantageously, the top of the reinforcement elementremains covered by the upper part. The reinforcement element thus does not come into direct contact with the user's foot, thus making it possible to maintain the comfort of the sports shoe. Similarly, the underside of the reinforcement elementis covered by the lower part. The reinforcement element thus does not come into direct contact with the ground. Damage to the reinforcement element by contact with rough terrain, for example stones, can thus be avoided. In an alternative embodiment of the invention, the reinforcement elementcould be completely embedded in the solewithout any face being visible from outside the sole, or alternatively comprise a face which is visible on only one of the two lateral sides of the sole.

The reinforcement elementis illustrated in isolation in. The reinforcement elementpreferably consists of a plastic material, optionally reinforced with fibres. For example, the reinforcement elementcan comprise polyamide (PA), acrylonitrile butadiene styrene (ABS), or any other plastic material with similar mechanical properties. The material can also be reinforced with different types of fillers such as glass or carbon fibres. The reinforcement elementcan be a monolithic element, for example obtained by moulding, in particular by injecting plastic into an injection mould.

The reinforcement elementis a component of the sole which gives it rigidity, stability and dynamism. The reinforcement element has a specific shape and dimensions which allow it to achieve these objectives without making the soleheavy and without impairing the capacity of the sole to absorb shocks, in particular the vertical shocks which occur when the front of the foot or the heel come into contact with the ground.

In relation to, it can be seen that the reinforcement elementcomprises a rear part, a front partand a central hingeconnecting the front partto the rear part. The rear parthas a positioning, shape and rigidity which are suitable for obtaining a particularly stable striking of the ground. The front parthas a positioning, shape and rigidity which give the sole a certain elasticity, thus allowing particularly effective transmission of the strike of the user.

The rear partand the front parthave respectively a length Land a length Lwith respect to the longitudinal axis X. The total length Lof the reinforcement elementwith respect to the longitudinal axis X is equal to the sum of the lengths Land L. The length Lpreferably lies within the range defined by 70% of the length Land 100% of the length L. The total length Lof the reinforcement elementcan be between 50% and 80%, preferably between 60% and 70%, of the total length Lof the solewith respect to the longitudinal axis X.

The central hingecan be positioned substantially at the centre of the reinforcement elementor slightly towards the front of the reinforcement element with respect to the longitudinal axis X. The central hingecan be positioned at a distance dfrom the rear edge of the sole which is between 50% and 70% of the total length Lof the sole.

The rear parthas a width Lwith respect to the transverse axis Y which is strictly greater than the width Lof the front partwith respect to this same axis. In particular, the width Lcan be at least equal to 150% of the width L, preferably at least equal to 200% of the width L. The width Lof the rear partcan be substantially equal to the width Lof the solewith respect to the transverse axis Y, the width Lbeing considered at the midpoint of the length of the sole with respect to the longitudinal axis X.

In order to fully understand the functioning of the reinforcement element, certain characteristics of the anatomy of the foot in relation toshould also be pointed out. The bones of the foot comprise various bones including the calcaneus, the talus, the navicular bone, the cuboid bone, the cuneiform bones.,.,., five metatarsals.,.,.,.and.and phalanges. The first metatarsal.is positioned on the same side as the big toe and the fifth metatarsal.is positioned on the same side as the little toe. The phalangesare positioned as an extension of the metatarsals. The tibiaand the fibulaextend upwards from the talus. When running, the phalanges articulate relative to the metatarsals.

The foot naturally comprises three points,,of contact with the ground by means of which a person can remain stable when standing on just one foot. A first contact point, or posterior contact point, is positioned directly below a lower end of the calcaneus. The first contact pointthus corresponds to the zone of the heel which first comes into contact with the ground when walking or running. A second contact point, or anteromedial contact point, is positioned directly below a head of the first metatarsal., in other words directly below a front protuberance of the first metatarsal.. A third contact point, or anterolateral contact point of the foot, is positioned directly below a head of the fifth metatarsal.. The three contact points,andare not aligned and are therefore positioned at the three vertices of a triangle.

The foot also comprises a plantar aponeurosis, also known as the plantar fascia. The plantar aponeurosisis a thick band of connective tissue situated on the bottom of the foot. It extends from the calcaneusas far as the heads of the metatarsals.,.,.,.and., thus forming the plantar arch or plantar vault. It comprises a set of fibres extending longitudinally, shown by dotted lines in.

The plantar aponeurosisforms a relatively soft zone on the bottom of the foot, in contrast to the three contact points,andwhich are firmer zones. The plantar aponeurosisplays a crucial role in maintaining the arch of the foot and in transmitting force when walking.

In, the anatomy of the foot shown inhas been superposed with the reinforcement elementin order to clearly display the position of the latter. The reinforcement elementis intended to extend below the plantar aponeurosisand at a distance from the three contact points,,. The reinforcement elementtherefore does not extend below any of the three contact points,and. The three contact points,andof the foot are thus free of the reinforcement element. The three contact points,andare thus effectively cushioned by the shock-absorbing layersandof the sole without the reinforcement elementdisturbing the shock-absorbing effect of these layers. Conversely, the soft tissues of the foot are effectively supported and protected by the reinforcement element.

The rear partof the reinforcement element extends in particular within the intermediate partof the sole. The rear partextends in particular below the navicular bone, below the cuboid bone, below the cuneiform bones.,.,., and below a rear part of the five metatarsals.,.,.,.and.. The rear partextends mainly in front of the calcaneus. The reinforcement element therefore does not extend below the calcaneusor only below a front part of the calcaneus. In particular, the rearmost point or edge of the reinforcement elementis positioned in front of the first contact point. Advantageously, the rearmost point or edge of the reinforcement elementis spaced apart from the first contact pointby at least approximately one centimetre, or even at least 15 millimetres, or even at least two centimetres.

The front partof the reinforcement element extends longitudinally between the two contact pointsand. In particular, the front partextends mainly below a front part of the second metatarsal.and/or below a front part of the third metatarsal..

The central hingeof the reinforcement element allows the front partto be decoupled from the rear part. The central hingecan in particular be formed by a narrower portion of the reinforcement elementalong the transverse axis Y. In other words, the dimension of the reinforcement elementalong the transverse axis Y is smaller at the central hingethan at the level of zones of the reinforcement elementsituated at the front and at the rear of the central hinge. As can be seen in, the central hingeis positioned inside the triangle formed by the three contact points,andof the foot.

The front partof the reinforcement element is less rigid than the rear part. Because of this difference in rigidity, the reinforcement elementbends elastically exclusively or almost exclusively at its front partwhen the foot exerts a vertical bending force on the reinforcement elementwhen running. The rear partremains completely undeformed when such a bending force is exerted. Shown inin dashed lines Tand Tis the shape of the reinforcement elementwhen it is subject to a bending force which is representative of the bending force exerted by the foot when running. By virtue of the difference in rigidity between the rear partand the front part, the rear partremains undeformed, which gives the sports shoe stability, whilst the front part provides elasticity and allows effective propulsion of the user.

As can be clearly seen in, the front partcomprises two longitudinal branches,extending parallel to each other. The front partthus has substantially the shape of a U or a tuning fork. The two longitudinal branchesandmeet at the hinge. A first longitudinal branchextends below an inner half of the plantar aponeurosis, and in particular below the second metatarsal.. A second longitudinal branchextends below an outer half of the plantar aponeurosis, and in particular below the third metatarsal.. Each of the two longitudinal branchesandcan bend independently of the other branch. The use of at least two branches thus allows the sole to better conform to the shapes of uneven terrain. In particular, the presence of two branches improves the lateral stability and the lateral dynamism of the shoeduring the phases of striking, or driving off from, the ground. If the foot strikes the ground more on its inner half, the first longitudinal branchwill tend to deform more than the second longitudinal branch. The first longitudinal branchwill provide dynamism to the strike of the foot, whilst the second longitudinal branchwill provide stability. Conversely, if the foot strikes the ground more on its outer half, the second longitudinal branchwill tend to deform more than the first longitudinal branch. The second longitudinal branchwill provide dynamism to the strike of the foot, whilst the first longitudinal branchwill provide stability. The use of at least two branches is therefore particularly useful for trail running.

The first longitudinal branchcomprises a substantially straight inner lateral edgeand a substantially straight outer lateral edge. Similarly, the second longitudinal branchcomprises a substantially straight inner lateral edgeand a substantially straight outer lateral edge. The four edges,,,are substantially parallel to the longitudinal axis X or possibly slightly inclined towards the inner edge of the foot in order to take account of the natural shape of the foot. The width L, Lof the two longitudinal branchesandis therefore substantially constant along these longitudinal branches. Each longitudinal branch,can comprise a free end. For each longitudinal branch, a terminal zone can be defined as a zone including the free end and whose length along the longitudinal axis is equal to 10% of the length of the branch in question. The width of each longitudinal branch,at its terminal zone can be strictly decreasing. The width Lis substantially equal to the width L. The distance dseparating the two longitudinal branchesandis also substantially constant along these longitudinal branches. The thickness eof the two longitudinal branchesandalong the vertical axis Z can be uniform, in other words constant along these longitudinal branches, for example in the order of one or two millimetres.

In one alternative embodiment, the front partcould comprise a different number of longitudinal branches, for example a single longitudinal branch. Conversely, the front part could comprise at least three longitudinal branches. In all cases, the longitudinal branch or branches extend at a distance from the contact points,and.

The rear partof the reinforcement element extends overall within a horizontal plane. The rear partcan be plane or slightly curved upwards. The rear parthas the form of a perforated plate. The rear partthus comprises a set of openings,,,,,,with a closed contour. An “opening with a closed contour” is understood to be a hole traversing the rear part, the contour of which forms a line closed on itself. The integration of contoured openings makes it possible to lighten the rear partwithout significantly impairing its rigidity. The openings,,,,,,can each comprise at least one dimension greater than or equal to 1 cm, even greater than or equal to 2 cm. The openings,,,,,,can comprise non-circular shapes, in particular polygonal shapes. The adjacent sides of each polygonal shape can be connected by rounded portions.

The rear part also comprises a set of substantially straight arms,,,delimiting the openings,,,,,,. The arms,,,are connected to one another in a network pattern. A first armextends from the hingerearwards and towards an inner side of the reinforcement element. An angle formed between the first armand the longitudinal axis X can be, for example, between 30° and 45° inclusive. A second armextends from the hingetowards the rear end of the inner side of the reinforcement element. An angle formed between the second armand the longitudinal axis X can be, for example, between 10° and 30° inclusive. A third armextends from the hingetowards the rear end of the outer side of the reinforcement element. An angle formed between the third armand the longitudinal axis X can be, for example, between 10° and 30° inclusive. A fourth armextends from the hingerearwards and towards an outer side of the reinforcement element.

An angle formed between the fourth armand the longitudinal axis X can be, for example, between 30° and 45° inclusive. The four arms,,,thus form four spokes which extend from the hingerearwards and in different directions.