Shoe with spring plate

Abstract

The disclosed invention consists of a One-piece spring plate (32) as part of a shoe (10), in particular a sports shoe (10), comprising at least one strand made from fibre containing composite material, wherein the one-piece spring plate (32) is fixable between a midsole (31) and an outsole of the shoe (10) by fixing means and the one-piece spring plate (32) is curved in its course from a forefoot section (A) via a midfoot section (B) to the hindfoot section (C) analogously to the sole of the foot of a user, providing increased suspension characteristics in any type of terrain. This ist reached by a one-piece spring plate (32) comprising a lateral strand (320) ending in a lateral tine (3201) in forefoot section (A) and a medial strand (321) forked into a first medial tine (3211) and a second medial tine (3212), wherein first medial tine (3211) and outer second medial tine (3212) are running spaced apart and bifurcated from each other, and wherein both strands (320, 321) are connected in the midfoot section (B) by a connecting bar (322), which has a slope from lateral side of the one-piece spring plate (32) to medial of the one-piece spring plate (32) with an angle (α) between 5° to 10°.

Description

[0001] SHOE WITH SPRING PLATE

[0002] TECHNICAL FIELD

[0003] The invention includes a one-piece spring plate as part of a shoe, in particular a sports shoe, comprising at least one strand made from fiber containing composite material, wherein the one-piece spring plate is fixable between a midsole and an outsole of the sport shoe by fixing means and the one-piece spring plate is curved in its course from a forefoot section via a midfoot section to the hindfoot section analogously to the sole of the foot of a user, and a shoe comprising a spring plate and an outsole with suspension structure.

[0004] STATE OF THE ART

[0005] Shoes, more precisely shoe soles are subjected to substantial compressive loads. In particular in case of sports shoes, there are ground reaction forces, which exceed several times the body weight, when contacting the ground with the heel and during push-off at the end of the step cycle. Accordingly, a sole construction must on the one hand provide a sufficient cushioning comfort to avoid premature fatigue or even injuries of the muscles or the bones. On the other hand, it must be capable to withstand these forces over an acceptable lifetime.

[0006] From EP1048233 a shoe in particular a sprint shoe, having a plate arranged in the sole area of the shoe, wherein the plate extends essentially over the complete length of the sole area, is essentially planar shaped in the forefoot part to allow an elastically bending of the plate in longitudinal direction, is known. An objective in the construction of sprint shoes is the elastic storing of energy by the shoe during the course of movements. During each landing phase the shoe is deformed in the forefoot part by the rolling- off with the ball of the foot and the toes. During the subsequent push- off with the toes the foot is straightened and the shoe returns into its straight original shape. This procedure is repeated during running with each step.

[0007] To improve the springback effect, US 6553692 discloses a complex arrangement for the heel part of a shoe which transforms a compression movement in the sole into a compression or elongation of a horizontally arranged coil spring. Also here there is a significant residual volume of the cushioning system so that the explained difficulties are not avoided. Furthermore, the design is so complex that it is inconceivable to economically manufacture the corresponding shoe.

[0008] The development has recently been moving away from flat carbon plates, which can be seen for example in DE102006059658. A complex and elaborate spring construction has been introduced here. Such a structure is much more expensive to produce and clunky to use, so this route was probably not pursued.

[0009] To improve the stability by stiffening elements, EP3868243 introduced curved hollow tubes made of fibre composite material. But these sole constructions, comprising at least two reinforcing members, are so stiff that no spring effect is achieved. Although this solution seems to be good against lateral tilting, it leads to a deterioration of the rolling characteristics of the shoe.

[0010] The so far known sports shoes with spring plates act quite similar to a spring storing energy when the user bend it during the stride and releasing it when the user move forward. The development has gone in the direction of several carbon fiber plates and more elaborate structures to improve the suspension in any railing.

[0011] A two pieces spring plate with a lateral strand and a medial strand is described in US2022142296. Both strands are arranged separately within the midsole or outsole and their cross-sections are curved according to the arch of the sole of the foot. A connection between the two strands is also mentioned, which is formed from a flexible material that accordingly differs from the strands.

[0012] Such plates are performing well on an even terrain, like roads, the plate is conceived to bend in a substantially perpendicular way compared to the motion. But such plates still show poor adaptability to uneven terrain, which has to be improved.

[0013] DESCRIPTION OF THE INVENTION

[0014] The disadvantages described above, which are known from the prior art, will be eliminated by the present device.

[0015] The present invention has set out to create a spring plate that provides increased suspension characteristics in any type of terrain and optimally supports the foot and reduces foot muscle fatigue.

[0016] BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Further understanding of various aspects of the invention can be obtained by reference to the following detailed description in conjunction with the associated drawings, which are described briefly below.

[0018] It should be noted that in the differently described embodiments, the same parts are provided with the same reference symbols or the same component names, the disclosures contained in the entire description being able to be applied analogously to the same parts with the same reference symbols or the same component symbols.

[0019] A preferred exemplary embodiment of the subject matter of the invention is described below in conjunction with the attached drawings.

[0020] FIG. 1 shows a sports shoe with invisible spring plate according to the present invention.

[0021] FIG. 2 shows an exploded view of the components of the sports shoe of Figure 1, with clearly visible one-piece spring plate between midsole and outsole.

[0022] FIG. 3 shows a top view of a one-piece spring plate, the outer outline of the midsole and indicated foot bones of a user to illustrate the relative alignment, while

[0023] FIG. 4 shows a) a top view of the spring plate with information on the shape and b) a side view of the spring plate.

[0024] FIG. 5 shows another sports shoe with invisible spring plate on another embodiment of the outsole, while

[0025] FIG. 6 shows an exploded view of the one-piece spring plate and the outsole with suspension structure of the sports shoe of Figure 5.

[0026] DESCRIPTION

[0027] With reference to the appended FIGS. 1 and 2, there is illustrated a footwear 10 according to the present invention, comprising in particular an upper 20, a sole body 30 and a outsole 40, most preferred with suspension structure.

[0028] Terms such as 'top', 'bottom', 'inside', 'outside' or the like will be used in the following description; the expert in the field will have no difficulty in understanding that these terms refer to the position of footwear 10 in its normal operating position, i.e. in use, as depicted in the attached figures.

[0029] The upper 20 comprises a flexible, hollow body shaped to receive the user's foot and provided, for this purpose, with a top opening 21 to allow the footwear 10 to be fitted.

[0030] Preferably, said upper 20 is obtained by means of 'knit' technology, i.e. it has a flexible sock-like structure which is obtained by thermoforming from a seamless knitted fabric tube made in one piece by a knitting machine. However, other types of uppers, made from the most suitable materials for the desired use, can be provided.

[0031] The upper 20 can be subdivided, by way of reference, into three regions, named according to their position with respect to the user's foot: in particular, as better observed in FIG. 2, said upper 20 defines a forefoot region 23, which corresponds to the portion of the upper 20 placed in correspondence with the upper part of the toes of the user and includes the toe P of the footwear, a midfoot region 24, which corresponds to the portion of the upper 20 placed in the intermediate upper part of the foot of the user, and a hindfoot region 25, which corresponds to the portion of the upper 20 placed in proximity to the heel T of the footwear 10.

[0032] In addition, the upper 20 includes a bottom region 22, which corresponds to the portion of the shoe located at the sole of the user's foot.

[0033] The upper 20 also defines an inner medial side (not visible in the figures) and an outer medial side 26, both extending on opposite sides of the foot, from toe P to heel T through each of the regions 23 - 25.

[0034] Lacing means 27 of a known, advantageously releasable type are preferably associated with the upper 20, being preferably arranged at the top thereof, preferably in the midfoot region 24 and in the vicinity of the opening 21; said lacing means 50 are suitable for modifying the dimensions of the inner cavity defined by the upper 20 so that the latter adapts to the conformation of the user's foot, and also facilitating the entry and exit of the foot with respect thereto.

[0035] The sole body 30 comprises at least one midsole 31 suitable for association with the upper 20 to support the sole of the user's foot. Preferably, said midsole 31 is formed of a tiled element, configured to essentially copy the contour of the sole of the user's foot and made of an advantageously flexible material, preferably having a hardness between 47 and 53 ShC (according to ISO 868), capable of conferring comfort to the user and effectively cushioning shocks during walking or running. Preferably, said midsole 31 comprises a thermoplastic elastomer, most preferred a polyamide elastomeric material, such as polyehter block amide, PEBA.

[0036] One example of the outsole 40 with suspension structure 40 is connected to the said upper 20, on the side opposite the top opening 21 of the upper 20 and comprises a plurality of resilient suspension brackets 41, each suspension bracket 41 defining corresponding distinct and separate ground support surface 42. Said suspension brackets 41 are arranged side by side in succession around the entire perimeter of the upper 20, while the bodies of each resilient suspension bracket 41 are spaced apart from each other by means of the interposition of a corresponding plurality of free gaps 43, so that each resilient suspension bracket 41 is elastically deformable independently of the others. These resilient suspension brackets 41 are therefore suitable for compressing to attenuate ground reaction forces, and the gaps 43, which alternate with the suspension brackets 41, allow the suspension structure 40 to flex, accompanying the natural bending of the foot during rolling.

[0037] All suspension brackets 41 are divided by free spaces 43 between neighbouring suspension brackets 41.

[0038] To achieve a spring effect, a one-piece spring plate 32 is also used here, consisting of a first lateral strand 320 and a second medial strand 321. Both strands 320, 321 run from a forefoot section A via a midfoot section B to a hindfoot section C, whereby the spring plate 32 is only one component. The spring plate 32 is fixed between midsole 31 and outsole 40 by known means or may even be inserted into the body of midsole 31.

[0039] The spring plate 32 and all its components comprises a carbon fiber composite material to achieve the desired stiffness. This material combines excellent elastical properties with a reduced weight. The material for the spring plate is preferably a composite material of carbon fibers which are embedded into a matrix of resin. Also Kevlar=Aramid fibers, short for aromatic polyamide, or glass fibers might be used. These materials combine high stiffness and a small energy loss with a low weight. Further, also the use of spring steel or other elastic metal alloys is possible. Plastic materials like Pebax or Hytrel have advantages with respect to their manufacture by injection molding, they obtain, however, the necessary elastic properties only by an additional reinforcement with fibers.

[0040] The thickness of all the spring plate 32 components is between about one millimeter and three millimeters, because there is a risk of breaking under high load. Most preferred is a thickness of the one piece spring plate 32 of 1 mm.

[0041] To increase stability and robustness, the spring plate 32 and the two strands 320, 321 are specially shaped. The lateral strand 320 encloses a lateral tine 3201 in forefoot section A and runs curved, according to the anatomy of the foot, curved with rounded corners from forefoot section A to hindfoot section C.

[0042] The medial strand 321 runs approximately parallel to the lateral strand 320 from hindfoot section C to midfoot section B. There, the medial strand 321 forks into a first medial tine 3211 and a second medial tine 3212 starting from a connection bar 322 in midfoot section B and thus runs in a bifurcated manner to forefoot section A, where it ends. The corners of the medial strand 321 are also rounded to prevent predetermined breaking points and the risk of injury.

[0043] The connection point between lateral strand 320 and medial strand 321, the connecting bar 322, like the other components, is made of the same material as spring plate 32 and accordingly all components are molded to each other.

[0044] In forefoot section A, lateral tine 3201, first medial tine 3211 and second medial tine 3212 are spaced apart from each other, with first medial tine 3211 being essentially straight and resembling a finger, while outer tines 3201, 3212 each describe an arc laterally and medially, respectively, before terminating at the end of forefoot section A.

[0045] In Figure 3, toes I to V are shown in relation to spring plate 32 in a corresponding size. It can be seen that the lateral tine 3201 is at the level of toes I and II, the first medial tine 3211 is at the level of toes III and IV and the second medial tine 3212 is at the level of the big toe V. The ball of the foot is thus optimally supported and rolling is improved. The medial tine 3211 and second medial tine 3212 provide a kind of cradle surrounding the 1st metatarsal head thus providing the perfect spot for the foot to put pressure on and receive the elastic spring effect in return. Due to the bifurcation of the medial strand 321, a main load zone of the ball of the foot, shown with a dotted circle, is optimally cushioned in the forefoot section A. The ball of the foot is thus optimally supported. Since the plurality of tines 3201, 3211, 3212 is formed and the bifurcation is achieved in forefoot section A, the spring effect of the sports shoe can be achieved in any terrain.

[0046] In midfoot section B, where first medial tine 3211 and second medial lateral tine 3212 starting together from connection bar 322, another support point for the foot is created, preventing pronation, which is indicated by the dashed circle.

[0047] The midfoot section B of the spring plate 32 is in an arched shape to follow the anatomy of the foot. This arch is not developing in a parallel direction compared to the longitudinal axis of the foot, but angled with a angle a, with 5° to 10°, most preferred with 6 degrees from lateral to medial part of the foot. This follows the actual direction in which the anatomy of the foot naturally moves and further improve the anti- pronation effects of the geometry of the spring plate. Looking at the spring plate 32 in the direction of its longitudinal axis, one can see a slope by the angle a from the lateral to the medial side of the one-piece spring plate 32.

[0048] In the hindfoot section C, the spring plate 32 with its divided lateral strand 320 and medial strand 321 helps to provide the spring effect when the user release the weight from the sports shoe 10. The larger space between both hindfoot section C parts of the lateral strand 320 and medial strand 321 allow the heel of the user to be in direct contact with the midsole 31 and therewith the midsole's soft material providing shock absorption and comfort while running. As can be seen in Figure 4a, the three tines of spring plate 32 have maximum spacings d which vary in their course, whereby no straight edges are formed. The maximum distances are preferably in the range from 5 mm to 15 mm, particularly preferably 10 mm.

[0049] The width b of the approximately central connecting bar 322 is between 15 mm and 30 mm for all sizes of spring plates 32, preferably 20 mm. As shown, the connecting bar 322 runs at a slight angle to the longitudinal axis of the spring plate 32.

[0050] To illustrate the curvature of the spring plate 32 according to the anatomically given foot curvature of the user, Figure 4b shows sections through the lateral strand 320 and the medial strand 321, whereby the elevation of the medial strand 321 relative to the lateral strand 321, as explained above, is also apparent.

[0051] Thus, lateral strand 320 and medial strand 321 are divided in hindfoot section C and converge in midfoot section B, revealing a single bifurcation in hindfoot section C and showing a double bifurcation in forefoot section A.

[0052] Especially in combination with the outsole 40 with suspension structure, the spring plate 32 is particularly efficient.

[0053] The suspension brackets 41 are one-piece elements and could be only one suspension bracket 41 is shown in Figure 5 / 6 or are provided in a number greater than four, completely distributed around the upper 20 and the sole body 30 with respect to the ground, as shown in Figure 1.

[0054] All suspension brackets 41 are individually glued or welded to the ground facing part of the upper 20 respectively the sole body 30. Each suspension bracket 41 is embracing the upper 20 and the sole body 30 at least partly. More preferred is the attachment of at least eight and up to sixteen suspension brackets 41 in the course of the circumference of the sole part of upper 20 and sole body 30.

[0055] The suspension brackets 41 enclose the upper 20 and are fixed non- detachably to the sides and underneath, so that the upper 20 is partially supported and a plane is formed for the tread by ground support surfaces 42.

[0056] Preferably, as best seen in FIG. 1, each suspension bracket 41 has a conformation suitable for at least partially enveloping the lower lateral edge of the upper 20.

[0057] The resilient suspension brackets 41 should be made of EVA or other polymeric materials having different densities in order to confer different mechanical characteristics according to the arrangement on the footwear.

[0058] In general at least one pair of adjacent resilient suspension brackets 41 is used and the suspension brackets 41 are connected via a connecting bridge 44, extending into the corresponding free space 43 between adjacent suspension brackets 41 to facilitate assembly on the upper 20; advantageously, all or some of the suspension brackets 41 may be connected via corresponding connecting bridges 44. Also possible is a direct connection of two directly neighbouring suspension brackets 41 in the area of the heel T or of the toe P of the upper 20.

[0059] A solution of a knitted upper 20 with spring plate 32 to be layed on a suspension bracket 41 of the outsole 40 with suspension structure is shown in Figure 6. Of course the form of the suspension brackets 41, the ground support surface 42 and the free spaces 43 can vary, because the spring plate 32 ist the most interesting part of the sports shoe 10. List of reference signs

[0060] 10 sports shoe

[0061] T heel

[0062] P toe

[0063] 20 upper (knitted upper)

[0064] 21 top opening

[0065] 22 bottom region

[0066] 23 forefoot region

[0067] 24 midfoot region

[0068] 25 hindfoot region

[0069] 26 outer medial side

[0070] 27 lacing means

[0071] 30 sole body

[0072] 31 midsole (preferred an insole)

[0073] 32 spring plate = double forked one-piece spring plate

[0074] A forefoot section (area of toe bones)

[0075] B midfoot section

[0076] C hindfoot section (open in area of tarsal bone)

[0077] 320 Lateral strand (one tine, curved, stiitzt laterale Fusssaule) 3201 lateral tine

[0078] 321 Medial strand (two tines, forked in forefoot section, stiitzt medial Fusssaule)

[0079] 3211 first medial tine

[0080] 3212 second medial tine

[0081] 322 Connecting bar (in midfoot section) b maximum width of connecting bar d maximum distance between strands respective tines in A a bending angle (between 5° and 10°, steady slope from lateral to medial

[0082] 40 outsole with suspension structure

[0083] 41 suspension bracket

[0084] 42 ground support surface

[0085] 43 free space

[0086] 44 bridge

[0087] I to V Toe end links

Claims

PATENT CLAIMS1. One-piece spring plate (32) as part of a shoe (10), in particular a sports shoe (10), comprising at least one strand made from fiber containing composite material, wherein the one-piece spring plate (32) is fixable between a midsole (31) and an outsole (40) of the shoe (10) by fixing means and the one-piece spring plate (32) is curved in its course from a forefoot section (A) via a midfoot section (B) to the hindfoot section (C) analogously to the sole of the foot of a user, characterized in that the one-piece spring plate (32) comprises: a lateral strand (320) running curved with rounded corners from hindfoot section (C) to forefoot section (A) along the outer contour of the sports shoe (10) analogous to the foot anantomy ending in a lateral tine (3201) in forefoot section (A) and a medial strand (321) running approximately parallel to the lateral strand (320) curved along the inner contour of the sports shoe (10) analogous to the foot anantomy with rounded corners from hindfoot section (C) to midfoot section (B) where the medial strand (321) forks into a first medial tine (3211) and a second medial tine (3212), wherein first medial tine (3211) and outer second medial tine (3212) are running spaced apart and bifurcated from each other, and wherein both strands (320, 321) are connected in the midfoot section (B) by a connecting bar (322), which has a slope from lateral side of the one-piece spring plate (32) to medial of the one-piece spring plate (32) with an angle (a) between 5° to 10°.

2. One-piece spring plate (32) according to claim 1, wherein the slope from lateral side of the one-piece spring plate (32) to medial of the one-piece spring plate (32) shows an angle (a) of six degrees.

3. One-piece spring plate (32) according to one of the preceding claims, wherein the forefoot section (A) has a shape of three fingers, with the first medial tine (3211) running straight between the lateral tine (3201) and second medial tine (3212), which are both bent towards the longitudinal axis.

4. One-piece spring plate (32) according to claim 3, wherein outer tines (3201, 3212) each describe an arc laterally and medially, enclosing the inner first medial tine (3211), before all three tines are terminating at the end of forefoot section (A).

5. One-piece spring plate (32) according to one of the preceding claims, wherein the first and second medial tines (3211, 3212) provide a kind of cradle surrounding the 1st metatarsal head of toe V, when one-piece spring plate (32) is in use as part of a shoe (10).

6. One-piece spring plate (32) according to one of the preceding claims, wherein an enlarged space between both hindfoot section (C) parts of the lateral strand (320) and medial strand (321) are enclosing the verses of a user, allowing the heel of the user to be in direct contact with the midsole (31) and therewith the midsole's soft material providing shock absorption and comfort while running.

7. One-piece spring plate (32) according to one of the preceding claims, wherein all strands (320, 321) and the connecting bar (322) are comprising the same carbon fiber matrix compositematerial and / or aromatic polyamide fiber matrix composite material and / or glass fiber matrix composite material, to achieve the desired stiffness.

8. One-piece spring plate (32) according to claim 7, wherein the constant thickness of all spring plate (32) components is between one millimeter and three 3 millimeters, most preferred 1 mm.

9. One-piece spring plate (32) according to one of the preceding claims, wherein the maximum spacings (d) between lateral tine (3201) and first and second medial tines (3211, 3212) variies between 5 mm to 15 mm, most preferred maximum 10 mm.

10. One-piece spring plate (32) according to one of the preceding claims, wherein the width (b) of the approximately central connecting bar (322) is between 15 mm and 30 mm for all sizes of spring plates (32), preferably 20 mm.

11. Shoe (10), comprising an upper (20), a midsole (31) and an outsole (40), characterized by that between midsole (31) and outsole (40) is arranged a one-piece spring plate (32) according to one of the preceding claims and the outsole (40) has a suspension structure comprising a plurality of suspension brackets (41) arranged along the outline of the midsole (31), spaced apart by free spaces (43) and partially connected by bridges (44).

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