Shoe sole with a midsole having firmness and density variations

The present invention relates generally to shoe structures. The present invention particularly relates to running shoe structures. The present invention more particularly relates to changes in the structure of such shoes with a sole contour, which as a basic concept follows a theoretically ideal stability plane but deviates outwardly therefrom to provide stability beyond natural stability. More particularly, the present invention pertains to the use of structures that approximately correspond to a theoretically ideal stability plane but whose contour or profile extends beyond that for a person whose natural biomechanical ankle and ankle or ankle functions are more erroneously conventional due to lifelong use Shoes are compromised to provide stability beyond natural stability.

Conventional running shoes (see EP 013 0816 A) are unnecessarily uncertain. They seriously affect natural human biomechanics. The resulting unnatural foot and ankle movement leads to abnormally high-grade run injuries.

Confirmation of the unnatural effects of shoes unexpectedly resulted from the discovery that the bare bare foot is stable, nearly non-deformable at the extreme end of its normal range of motion, while the foot of an athlete or other person wearing any shoe is unnaturally unstable and abnormal prone to ankle sprains. Therefore, ordinary ankle sprains must be considered largely unnatural, though they are quite common. Compelling evidence shows that the stability of the bare foot is completely different from the stability of a shod foot.

The cause of shoe general instability is a critical but correctable design or design flaw. The hidden error inherent in traditional shoe designs is so extraordinarily fundamental that it has gone unnoticed until today. This error is demonstrated by a novel biomechanical test, a test unprecedented in its simplicity. The test simulates a lateral ankle sprain in a firm state. It is so simple that it is repeatable and verifiable by anyone; It takes only a few minutes and requires no scientific equipment or expertise.

The simplicity of the test belies its surprising and convincing results. It shows an obvious difference in stability between a bare foot and a running shoe, a difference that is so unexpectedly large that an obviously subjective test instead becomes clearly objective. The test shows without any doubt that all conventional shoes are unsafe and unstable.

The consequences of this clear discovery may be far-reaching. The same fundamental flaw in conventional footwear that is clearly demonstrated by the novel test also appears to be the major cause of chronic overuse injuries that are uncommonly frequent while running, as well as other sports injuries. It causes the chronic injuries in the same way that it causes ankle injuries, ie by seriously affecting the natural foot and ankle biomechanics.

Applicant has introduced the concept of a theoretically ideal stability plane as a structural basis for shoe sole constructions in the art. This concept, applied to footwear such as street shoes and sports shoes, is filed in pending US applications 07 / 219,387 filed July 15, 1988, 07 / 239,667 filed September 2, 1988 and 07 / 400,714 filed August 30, 1989, and in PCT Application No. PCT / US89 / 03076 filed July 14, 1989. The theoretically ideal stability plane described in these applications primarily serves to provide a neutral construction which allows the natural foot and ankle biomechanics of the foot to be adjusted as accurately as possible between the foot and the ground and the disturbance present in conventional shoes avoid the natural foot and ankle biomechanics.

The present invention is a modification of inventions disclosed and claimed in earlier applications and development of the application of the concept of the theoretically ideal stability plane to other shoe structures. Therefore, it presents certain structural ideas for shoe soles whose contour or profile deviates outwardly from the theoretical ideal stability plane in order to compensate for the erroneous foot biomechanics caused by the major flaw in conventional shoe designs identified in the earlier patent applications.

The shoe sole constructions in this application are based on the recognition that lifelong use of conventional shoes, the unnatural construction of which is inherently flawed, actually causes structural changes of the human foot and ankle. Conventional shoes have therefore changed the natural human biomechanics of many, if not most, individuals to an extent that must be compensated for by improved and therapeutic construction. The continued repetition of serious disturbances by conventional shoes has apparently caused individual biomechanical, possibly permanent changes, so that simply eliminating the causes is not sufficient. The residual effect must also be treated.

US Patent 4,305,212 discloses a shoe sole having, when viewed in a frontal plane cross-section, when the shoe sole is in an upright, unloaded condition, concave rounded inner and outer surface portions. The purpose of this structure is to simulate running in the sand or the like, so that the likelihood of the foot getting out of position and becoming over-mobile is less.

The object of the invention is to provide a shoe sole, which provides a higher stability than conventional Schuhsolendesigns.

These and other objects of the invention will become apparent from the following detailed description of the invention taken in conjunction with the accompanying drawings.

Brief description of the invention

In order to achieve the above-mentioned objects and eliminate the problems associated with conventional shoes, a shoe according to the invention has a sole, wherein a concavely rounded outer midsole surface portion and a first midsole material having a different density or strength than a second midsole material included in another part of the shoe sole is combined in a shoe sole. The midsole further has an outer surface that extends above the lowermost point of a most lateral portion of the inner surface. All of these features are considered in a frontal plane cross-section when the shoe sole is in an upright, unloaded condition. In their entirety, these features provide increased stability of the shoe sole.

In another aspect, the shoe has a naturally shaped sole structure that undergoes natural deformation that approximates the natural deformation of the foot under the same load. If the density or strength of the shoe brine is changed, you get a natural stability beyond.

These and other features of the invention will become apparent from the following detailed description of the invention.

Brief description of the drawings

Fig. 1 shows in a frontal plane cross-sectional view at the heel portion of a shoe, the applicant's earlier invention, ie, a naturally-molded sole-shaped shoe sole based on a theoretically ideal stability plane.

Figure 2 again shows, in a frontal plane cross-sectional view, the most common general case of Applicant's earlier invention, ie a solid profile shoe sole following the natural contour of the bottom of the foot and its sides, also based on the theoretically ideal stability plane.

FIGS. 3A to 3C are frontal cross-sectional views on the heel illustrating conventional applicant's prior art invention, ie, a quadrant-shaped shoe sole based on a theoretically ideal stability plane.

4 shows a frontal plane cross-sectional view at the heel of a shoe having naturally shaped sides similar to that of FIG. 1, wherein a portion of the shoe sole thickness is greater than the thickness corresponding to the theoretical ideal stability plane.

Fig. 5 is a view similar to Fig. 4, but of a shoe having solid profile side members, wherein the sole thickness increases with increasing distance from the centerline of the subsoil or ground contacting portion of the sole.

Fig. 6 shows a view similar to Fig. 5, wherein the thickness of the full-profile sole on each side increases continuously.

Fig. 7 shows a similar view to Figs. 4 to 6, wherein the sole thicknesses change in different sequences or patterns.

Fig. 8 shows a frontal plane cross-sectional view for illustrating a density change in the midsole area.

Fig. 9 is a view similar to Fig. 8, with the strongest or most rigid material disposed at the outermost edge of the midsole area.

Fig. 10 is a view similar to Figs. 8 and 9 showing still another density change, one of which is asymmetric.

11 shows a change in thickness of the sole for the embodiment with quadrants, wherein the theoretically ideal stability plane is exceeded.

Fig. 12 shows an embodiment with quadrants as in Fig. 11, wherein the density of the sole varies.

FIG. 13 shows a bottom sole tread construction by which a similar density change is obtained as in FIG. 10.

Fig. 14 shows embodiments as in Figs. 1 to 3, but wherein a portion of the shoe soles thickness is reduced such that the theoretical ideal stability level is exceeded.

FIG. 15 shows embodiments in which the sides both exceed and undercut the theoretically ideal stability level.

Detailed Description of the Preferred Embodiments

Figures 1, 2 and 3 show frontal plane cross-sectional views of a shoe sole based on the theoretically ideal stability plane corresponding to Applicant's earlier inventions, with the cross sections taken approximately at the ankle to illustrate the heel portion of the shoe. Figs. 4 to 13 show the same view of a further development of this invention. The reference numerals are similar to the reference numerals used in the Applicants' earlier copending applications, which are incorporated by reference for completeness of the disclosure in the present specification. In the figures, a foot 27 is arranged in a naturally shaped shoe with a top 21 and a sole 28. The shoe sole is normally in contact with the bottom 43 at about the lower middle heel portion, as shown in FIG. The concept of the theoretically ideal stability plane developed in the earlier applications defines, as mentioned, the plane 51 with respect to a locus of points determined by the thickness s of the sole.

Fig. 1 shows, in a cross-sectional view in the heel area, the application of the prior invention and shows that the inner surface of the shoe sole coincides with the natural shape of the foot and the thickness of the shoe sole in the frontal plane remains the same, so that the outer surface coincides with the theoretically ideal stability plane.

Figure 2 shows a solid profile shoe sole structure of Applicant's earlier invention following the natural shape of the entire foot, both at the bottom and at the sides, while maintaining a constant shoe sole thickness in the frontal plane.

The full-profile shoe sole ensures that the underside, which is slightly rounded in the unloaded state, deforms and flattens under load, just as the underside of the human foot is slightly rounded in the unloaded state and flattens out under load; therefore, the shoe sole material must be so composed that the natural deformation can follow that of the foot. Although the construction particularly relates to the heel, but also the rest of the shoe sole. Providing the most accurate match of the full profile sole structure with the natural foot shape allows the foot to function as naturally as possible. Under load, the structure shown in Fig. 2 would deform by flattening, so that it is substantially similar to Fig. 1. From this point of view, the naturally shaped side structure in FIG. 1 a more conventional, conservative structure corresponding to a special case of the more general solid profile structure in Figure 2, which most closely matches the natural shape of the foot but is least conventional. The amount of flattening obtained by deformation which is apparently different at different loads is not an essential element of the present invention.

Figs. 1 and 2 show frontal plane cross-sectional views of the underlying this invention essential concept of the theoretically ideal stability plane, which is also suitable for efficient natural movement of any kind, eg. Walking, jogging, walking or walking, theoretically ideal. Fig. 2 shows the most general case of the invention, the solid profile structure, which matches the natural shape of the unloaded foot. For any given person, the theoretically ideal stability plane 51 is determined firstly by the desired shoe sole thickness s in a frontal plane cross section and secondly by the natural shape of the foot surface 29 of the person.

For the in Fig. 1 The special case illustrated is the theoretically ideal stability plane for any person (or height average of persons) firstly by the given shoe sole thickness s at the frontal plane cross section, secondly determined by the natural shape of the person's foot and thirdly by the width of the person's load-bearing footprint 30b at the frontal plane cross section which is defined as the upper surface of the shoe sole, which is physically in contact with the human sole and carries it.

The theoretically ideal stability level for the special case consists of two sections. In Fig. 1, the first portion is a line segment 31b, which has the same length as a line 30b and in a shoe sole thickness corresponding distance s runs parallel thereto. This corresponds to a conventional sole just below the human foot and also corresponds to the flattened portion of the underside of the load-bearing sole 28b. The second portion is the naturally-shaped or profiled stability-imparting side outer edge 31a disposed on each side of the first portion, ie, the line segment 31b. Each point on the profiled side outer edge 31a is arranged at a distance that corresponds exactly to the shoe sole thickness s from the next point on the profiled side inner edge 30a.

The theoretically ideal stability plane is the basis of the present invention because it is used to determine a geometrically precise bottom side profile of the shoe sole matching the foot shape based on a top profile. In particular, the present invention relates to the exact geometrical relationship described above.

It can be clearly stated that each shoe sole profile, while having a similar shape extending beyond the theoretically ideal stability plane, will limit natural foot movement while decreasing the natural stability at each fall below that level, directly proportional to the extent of the deviation. The theoretically ideal stability plane was taken as the natural shape closest to the profile.

Fig. 3 shows in a frontal cross-sectional view another modification of Applicant's earlier invention, wherein stabilizing quadrant-shaped portions 26 are provided on the outer edge 28b of a conventional shoe sole indicated generally by reference numeral 28.

Fig. 4 shows the present invention, wherein the shoe sole thickness is greater than the theoretically ideal stability level corresponding thickness, so that the stability is slightly greater than the natural stability. The inevitable disadvantage is that the natural mobility is somewhat limited and the weight of the shoe sole is slightly larger.

Fig. 4 shows a case in which the thickness of the sole at each of opposite sides at portions of the sole 31a is larger by a degree gradually varying from a thickness s over a thickness s + s1 to a thickness s + s2 , In these structures, it has been taken into account that by making lifelong use of conventional shoes whose structure has defects that affect the natural biomechanics of humans, structural changes of the human foot and ankle have in fact been produced to an extent that must be compensated. In particular, one of the most common of the abnormal effects of the errors encountered in conventional shoes is a weakening of the long arch of the foot or arch, thereby increasing pronation. The structures provided by the present invention therefore modify applicant's earlier structures to provide stability greater than natural stability, and the invention should be particularly suitable for persons with generally low archs or arches that are too excessive Pronation, and the invention could also be applied exclusively on the medial side. Similarly, persons with high archs or arches, which are prone to supination and therefore may suffer lateral ankle sprain, would also benefit, and the structure could also be applied exclusively to the lateral side. A shoe for the general population, which compensates for both drawbacks in the same shoe, would have greater compensatory structural stability on both sides.

The novel structure shown in Fig. 4 allows, similar to Figs. 1 and 2, an approximately natural deformation of the unloaded bare foot corresponding natural deformation of the shoe sole, the shoe sole material must be composed so that the natural deformation of that of the foot follows.

In the structures according to the invention the essential novel aspect of the earlier structures is retained; ie, the profile of the shoe sole is adapted to the shape of the human foot. The difference is that the shoe sole thickness in the frontal plane can change instead of remaining uniformly constant. That is, the Fig. 4, 5, 6, 7 and 11 show in frontal plane cross-sectional views on the heel that the shoe sole thickness may increase beyond the thickness corresponding to the theoretical ideal stability plane 51 to provide stability greater than natural stability. Such changes (and the following changes) may be the same across all frontal plane cross sections, so that the thickness increases proportionally with respect to the theoretically ideal stability plane 51 from the front to the back of the shoe sole, or the thickness may be, preferably continuously, from one frontal plane to the next to change.

The exact measure of the increase in thickness of the shoe sole beyond that which corresponds to the theoretically ideal stability level can be determined empirically. Ideally, right and left shoe soles would be shaped or contoured for each person based on a biomechanical analysis of their foot and ankle dysfunction to provide optimal individual correction. If epidemiological studies indicate general patterns of correction for specific categories of persons or the population as a whole, mass-produced soled corrective footwear with profiled sides exceeding the theoretical ideal stability level would also be possible. It is expected that all such mass-produced corrective footwear for the general population would have a thickness exceeding the ideal stability level by up to 5 or 10%, while for more specific groups or individuals with more severe dysfunction, there may be an empirically determined need for greater corrective thicknesses on the order of up to 25% with respect to the theoretical ideal stability level. The optimum profile for the greater thickness can also be determined empirically.

FIG. 5 shows a modification of the further developed solid profile structure, wherein the shoe sole begins to thicken somewhat offset to the sides with respect to the theoretically ideal stability plane 51.

Fig. 6 shows a change in thickness, which is symmetrical as in the case of Figs. 4 and 5, but the shoe sole begins to thicken directly under the foot heel 27 at about the midline of the shoe sole with respect to the theoretically ideal stability plane 51. In fact, the thickness of the shoe sole in this case corresponds only at this starting point below the upright foot of the theoretically ideal stability plane. In the present invention, in which the shoe sole thickness changes, the theoretically ideal stability plane is determined by the smallest thickness in the direct load-receiving portion of the shoe sole, that is, in the portion in which direct tread or tread contact with the ground occurs; the outer edge or the edge region of the shoe sole is obviously excluded, because the thickness always decreases there to zero. The ability of the natural deformation of the structure according to the invention may cause some portions of the shoe sole to bear a load when actually loaded, especially when walking or running, even if they do not appear to be strained.

Fig. 7 shows that the thickness can also increase and then decrease; Other patterns or consequences of changes in thickness are possible. The alteration of the side profile thickness of the present invention may be symmetrical or asymmetric on both sides, particularly if greater stability is to be provided by the medial side than on the lateral side, although many other asymmetric changes are possible, and the pattern for the right foot may vary from differ from that for the left foot.

Figures 8, 9, 10 and 12 show that similar changes in the shoe center soles 127 (other portions of the shoe sole surface are not shown) provide similar, but similar, effects with respect to the changes described above with reference to Figures 4 to 7 Shoe sole thickness can be obtained. The main advantage of this method is that the structural theoretically ideal stability plane is maintained so as to maintain maximum possible, natural optimum stability and maximum possible efficient mobility.

The embodiments of midsoles having two and three sections of different densities shown in these figures are commonly used in conventional running shoes, and theoretically any number of sections of different densities are possible although through an alternating arrangement of sections having only two densities, such as shown in FIG 8, a continuously changing combined density is obtained. However, in Applicant's earlier invention, multiple density sections in the midsole 127 were not preferred because only a uniform density would result in a neutral shoe sole structure that would not affect the natural foot and ankle biomechanics, such as multi-section shoe soles having different densities the case is where different support levels are provided for different foot sections; Of course, such midsoles 127 with several sections with different densities were of course not excluded. In these figures, the density in the region d1 of the sole material is greater than the density in the region d, while in the region d2 the greatest density is present. In Fig. 8, a sole is shown with sections with two different densities, wherein in the area d, the lowest density is present.

Shoe soles in which a combination of sole thicknesses greater than the theoretical ideal stability plane thickness and center density variations, such as the density changes described above, are also used, but not shown.

Fig. 13 shows a tread structure of the insole 128, through which, due to a mean density change, a total of about the same shoe bottom density change is obtained as in Fig. 10. The smaller the supporting tread under any specific portion of the shoe sole, the less effective the total shoe sole density is the midsole 127 over this portion will deform more easily than when fully supported.

Fig. 14 shows embodiments similar to those of Figs. 4 to 13, but with a portion of the thickness of the shoe sole is reduced so that the theoretical ideal stability level is exceeded. It is to be expected that these embodiments, whose stability is less than the natural one, but which allow greater freedom of movement and whose sole weight leads to less bulkiness, are beneficial to a number of persons whose foot and ankle joint biomechanics are conventional shoes has worsened. In particular, it can be expected that the embodiments according to FIG. 14 Beneficial for people with very stiff feet who have limited range of motion and who tend to over-nip. More particularly, the invention is expected to be beneficial to individuals with significant bilateral foot-function asymmetry, ie, the tendency for pronation on one foot and supination on the other foot. Thus, it is believed that this embodiment is only applied to the shoe sole of the foot, which is prone to supination and only on the inner portion, optionally only on a portion thereof. It is believed that the range below the theoretically ideal stability level is at most about 5 to 10%, although a maximum of up to 25% could be beneficial in some individuals.

Fig. 14A shows an embodiment according to Figs. 4 and 7 but with naturally shaped sides, which falls below the theoretically ideal stability level. Figure 14B shows an embodiment similar to the fully contoured construction of Figures 5 and 6, but with the shoe sole thickness decreasing as the distance from the midsection of the sole increases. FIG. 14C shows an embodiment of the quadrant-side construction of FIG. 11 however, the quadrant sides increasingly fall below the theoretically ideal level of stability.

The diminished construction of Figure 14 would also apply to the density variation embodiment of Figures 8-10 and 12 and to the embodiment of Figure 13 using tread-forming for approximate density variation.

Figures 15 AC show, in cross-sections similar to those in copending application 07 / 219,387, that a quadrant side construction in the same shoe allows shoe sole sides extending beyond both the theoretically ideal stability plane as well as they fall short. The radius of an intermediate shoe sole thickness measured at (52) at the base of the fifth metatarsal bone shown in FIG. 15B is kept overall constant in the quadrant sides of the shoe sole including the heel (FIG. 15C) and the forefoot (FIG. 15A), so that the side thickness exceeds the theoretically ideal stability level at the heel and forefoot. Although possible, this embodiment is not preferred.

The same method can be applied to the naturally profiled sides or solid profile structures shown in Figs. 1, 2, 4 to 10 and 13, but this is also not preferred. In addition, as shown in FIGS. 15 DF, similar cross sections as shown in pending US Application 07 / 239,667 can be shown in the same manner as in FIGS. 15 AC shoe provided shoe sole sides whose thicknesses are both larger and smaller than the theoretically ideal stability level corresponding thickness, but the side thickness (or radius) is not constant as in Fig. 15 AC nor directly with the shoe sole thickness as shown in Applicant's pending applications, but instead changes indirectly with the shoe sole thickness. As in Figs. 15 DF, the shoe sole sidewall thickness changes from a dimension slightly less than the shoe sole thickness at the heel to a degree at the forefoot that is slightly larger. While this method is possible, it is also not preferred and may be applied to a quadrant-shaped side-portion structure, but it is not preferred here as well.

By the above shoe structures, the above-described objects of the present invention are achieved. However, it will be apparent to those skilled in the art that the foregoing description relates to preferred embodiments and that various changes and modifications may be made within the scope of the present invention as defined by the appended claims.