MX2008002075A - Shoe insole - Google Patents

Abstract

An insole providing cushioning and control of foot motion. The insole includes a stability cradle and a number of pods on the underside of the insole core or base. Some of the pods have different material properties selected to help control foot motion.

Description

SOLE FOR SHOE The present invention relates generally to an improved shoe sole and, more particularly, to a sole that provides better protection and support for the foot of the wearer.

BACKGROUND OF THE INVENTION The human foot is a very complex biological mechanism. When walking, the load exerted on the foot during the heel support is generally about one and a half times the body weight of a person. When running or carrying additional weight, such as a backpack, the loads exerted on the foot can exceed three times the body weight. The large number of bones, muscles, ligaments and tendons of the foot function to absorb and dissipate the forces of impact, support the weight of the body and other loads and provide forces for propulsion. Properly designed shoe soles can help the foot perform these functions and protect it from injury. The soles can be customized to meet the specific needs of an individual. These can be manufactured based on molds of the foot of the end user or can be made of a thermoplastic material that is molded according to the contours of the foot of the end user. However, it is not practical to manufacture such soles for the general public.

Like most custom-made items, custom soles tend to be expensive, due to the low volume and large amount of time required to manufacture and adapt them appropriately. To be practical for distribution to the general public, a sole must be able to provide benefits to the user without requiring individual adjustment and adaptation. A first type of sole that is commonly available in stores emphasizes foot protection, so that shock absorption is maximized. For individuals in general, protective soles work well when performing light to moderate activities, such as walking or running. That is, a protective sole provides sufficient protection and support for such activities. However, to perform more strenuous or technically more demanding activities, such as carrying a heavy backpack or traversing difficult terrain, a typical protective sole may not be adequate. Under such conditions, a protective sole itself would not provide sufficient support and control and could tend to be lowered during use. Another type of sole available on the market emphasizes control.

Typically, said soles are made to be relatively hard and rigid so as to control the bending and turning of the foot by limiting the movement thereof. The rigid structure is good for controlling movement, but it is not very comfortable. As a result, when the movement of the foot reaches a limit imposed by the rigid structure, the load exerted on the foot tends to change abruptly and the load exerted on the structures of the foot can be increased. Since biological tissues such as tendons and ligaments are sensitive to the load index they receive, abrupt change of load can cause injury or damage. In view of the above, it would be desirable to provide a sole available in the market that provides both protection and control. It would also be desirable to provide a sole that provides both protection and control and that is practical for use by the general public.

BRIEF DESCRIPTION OF THE INVENTION In view of the foregoing, therefore, one of the purposes of the present invention is to provide a sole available in the market that provides both protection and control. Another purpose of the present invention is to provide a sole that provides both protection and control and that is practical for use by the general public. The foregoing and other purposes and advantages herein are provided by a sole providing both motion control and protection. The sole includes an interaction system of components that cooperate to achieve a desired combination of motion control and foot protection. The components include a foam rubber center, a semi-rigid stability support and a series of protuberances and elastomeric insoles. The characteristics of the components, their size and shape, as well as their position, are selected to provide a desired combination of protection and control and, more specifically, to achieve a desired biomechanical function. In accordance with the principles of the present invention, a protective base or center is combined with a relatively rigid stability support and a series of elastomeric protuberances to form a sole providing protection, stability and control. By altering the size, shape and material properties of the protuberances, the soles can be designed to address issues of over / under-pronation, over / under-supination and other problems related to foot movement. In a preferred embodiment of the present invention, the sole components are fixed permanently to each other, to create a sole designed for a type or category of activity that is intended to be performed. Thus, many sole designs can be made available to cover a wide range of different activities. In an alternative embodiment of the invention, a sole may comprise a package that includes a series of interchangeable protuberances with different characteristics. Using said package, a user can selectively change the protuberances to customize the sole to fit a specific activity.

BRIEF DESCRIPTION OF THE DRAWINGS The foregoing, as well as other purposes and advantages of the present invention, will be understood by considering the following detailed description taken in conjunction with the accompanying drawings, in which similar reference characters refer to similar parts throughout them and where: Figure 1 is a schematic perspective view of an illustrative embodiment of a sole in accordance with the principles of the present invention. Figures 2 and 3 are perspective views showing, respectively, the base and stability support of the sole of Figure 1. Figures 4 to 7 are, respectively, dorsal (top), ground (bottom), side views (outside) and back of the sole of Figure 1. Figure 8 is a longitudinal cross-sectional view of the sole of Figure 1. Figures 9 and 10 are cross-sectional transverse views of the sole of Figure 1. And Figure 11 is a view of the super-imposed foot bones on a plan view of the sole of Figure 1.

DETAILED DESCRIPTION OF THE INVENTION Referring to Figures 1 to 11, a sole made in accordance with the principles of the present invention is described. As shown in the schematic view of Fig. 1, the sole 20 is a composite structure including the base 22, the stability support 24, the lateral bead protrusion 26, the middle heel protrusion 28, the mid-lateral protrusion foot 30, the front protuberance 32, the valgus pad 34 and the upper sheet 36. Although not visible in figure 1, the sole 20 also includes a thin pad disposed between the base 22 and the upper sheet 36, to form a transverse arch support 38 which is visible in figures 4 and 9. As shown in figure 2, the base 22 is generally in the form of a complete or partial sole. Preferably, the base 22 is made of one or more layers of foam rubber or other material having suitable protective properties. For example, the base 22 may include a top layer comprising approximately 2 mm of EVA foam with a durometer (hardness) of approximately Shore C 25-55 and a bottom layer comprising approximately 4.5 mm of EVA foam with an approximately Shore durometer C 40-65. More preferably, the material of the base 22 is selected based on an expected type of user activity of the sole. A softer material would be selected for a sole to be used for light activities, while harder materials would be more appropriate for demanding activities. For example, a base comprising an EVA top layer with a durometer of approximately Shore C 30-35 and a lower layer of EVA with a durometer of approximately Shore C 45, would be suitable bases for a sole designed for activities such as walking normally , while upper and lower layers of EVA with durometers of approximately Shore C 45-50 and Shore C 60, respectively, could be more appropriate for a sole that is intended to be used for walking while carrying a backpack. The base 22 has a raised edge 40 that surrounds the heel and extends partially along the sides of the foot, so that the sole adapts to the natural shape of the foot. As seen in figures 6 to 10, the height of the raised edge 24 is generally greater and the material of the base is thicker on the middle side of the foot and is smaller on the side. The base 22 also includes the recesses 42, 44 and 46 to coincide with the stability support 24, the front protuberance 32 and the valgus pad 34, respectively. The base 22 is partially arranged within the stability support 24, which provides some stiffness to the sole 20. Preferably, the stability support 24 is made of a material having sufficient stiffness to control the movement of the foot. For example, the stability support 24 can be made of a polypropylene with a Shore A 90 durometer.

The stability support 24 generally extends from the calcaneus through the midtarsal joints of the foot. However, the middle front portion has a shape that allows it to adapt to the movement downstream of the first metatarsal bone during the heel lift, as described below. The slits 58 around the heel and along the side of the stability support 24, help to improve the fit of the sole 20 in a shoe and to minimize movement between the sole 20 and the shoe. As shown in Figures 6 to 10, the stability support 24 includes walls that wrap around the sides and back of the base 22 to provide support for the foot. Preferably, the stability support 24 is approximately 3 mm thick and the walls are tapered from about 2 mm to about 0.5 mm. Preferably, the sides of the stability support 24 are higher on the medial side of the foot due to the greater load. For example, the middle side 48 of the stability support 24 extends upwardly below the medial longitudinal arch. The slots 50 improve the flexibility along the middle side of the stability support 24 without sacrificing the longitudinal arch support. Preferably, the base 22 is molded so that the portions 52 and 54 of the foam material project towards the slots 50 and the holes 56, so as to abut the outer surface of the stability support 24, so as to mechanically fix the stability support 24 and the base 22 together. Advantageously, the foam is also able to protrude through the slots 42 when the base 22 is compressed, e.g. while walking, to provide additional protection to the arch. The protuberances 26 to 30 are fixed to the lower part of the base 22 through the corresponding openings 60 to 64 in the stability support 24. The front protuberance 32 and the valgus pad 34 are fixed to the lower part of the base 22 forward of the stability support 24 and the upper sheet 36 is fixed to the upper surface of the base 22. As will be described later, the size, shape and location of these protuberances and cushions, are based on the location of different points. key anatomical foot and in the biomechanics of foot movement. The contact of the foot with the floor is generally divided into three phases: heel support, medium foot support and heel lift. During the heel support, the heel of the foot hits the floor with significant force. To cushion the impact, the side heel protrusion 26 is positioned along the rear and lateral side of the calcaneus (heel bone) and projects below the stability support 24. Preferably, the side bead extrusion 26 is made of a material that has adequate protective properties. For example, the side bead protrusion 26 may comprise approximately 6 mm of a polyurethane material with a durometer of approximately Shore C 40-60. More preferably, the characteristics of the lateral bead protrusion 26 are selected based on a type of activity that is intended to be performed. For example, a polyurethane having a durometer of approximately Shore C 45-50, would be suitable for the lateral bead extrusion 26 in a sole designed for activities such as walking normally, while a polyurethane having a durometer of approximately Shore C 50 -55 would be more appropriate in a sole designed for activities such as walking carrying a backpack. After the initial impact of the heel with the floor, the foot turns or enters prone position, putting the middle side of the heel in contact with the floor. The foot is sensitive to the amount of pronation, as well as to the rate at which pronation occurs. Pronation is natural and a certain degree of pronation is desirable, because it serves to absorb the tensions and forces exerted on the foot while walking or running. However, an excessive amount or pronation index could cause injuries. The stability support 24 provides a firm support along the middle portion of the foot, to help control the amount of pronation. The medial heel protrusion 28 helps control the pronation index by forming the medial heel protrusion 28 from a material with characteristics other than the lateral heel extrusion 26. For example, to reduce the pronation index, the heel protrusion Half 28 can be made from a material that is firmer than the side heel boss 26. A firmer or harder material does not compress as much or as quickly as a softer material under the same load. Therefore, an average heel protrusion made from a firmer material would be less compressed than a side bead protrusion made from a softer material. As a result, the mean heel protrusion 28 tends to resist or counteract pronation and thus helps reduce the degree and rate of pronation. Conversely, fabricating the medial heel protrusion 28 from a softer material than the lateral heel protrusion 26 would tend to increase the pronation number and index. Preferably, the firmness of the material used in the medial heel protrusion 28 is selected based on the firmness of the lateral heel protrusion 26 and on the type of activity to be performed. For example, the firmness of the lateral heel protrusion 26 and the medial heel protrusion 28, may differ by approximately 20 to 30% for a sole to be used in the performance of light to moderate activities. More specifically, the lateral and medial heel protuberances with durometer values of approximately Shore C 45-50 and approximately Shore C 60, respectively, would be suitable for a sole designed for use in the performance of a light walk. Loading a heavy backpack significantly increases the load exerted on the foot and the index of pronation during and after the support of the heel. Accordingly, the medial heel protrusion 28 can be made significantly firmer in a sole designed for use while walking carrying a backpack. As an example, a difference in firmness of approximately 20 to 40% could be more appropriate for carrying out such activities. More specifically, the lateral and medial heel protuberances with durometer values of approximately Shore C 50-55 and approximately Shore C 65-70, respectively, would be suitable for a sole designed for use while walking carrying a backpack. The half-foot bulge 30 provides protection and control to the side of the foot during the half-step portion of a step. Typically, the half-foot extrusion 30 is formed from a material having the same properties, e.g. firmness, than the lateral heel protrusion 26. However, a material having different characteristics can also be used. At the beginning of the propulsion or phase of lifting the heel of a step, the heel begins to rise from the floor and the weight passes to the metatarsal eminence of the foot. The front protuberance 32 is located below this part of the foot. Preferably, the front protrusion 32 is formed from a relatively elastic material, so that the energy put into the compression protrusion 32 is returned to help propel the foot in the heel lift. For example, the front protrusion 32 may comprise a layer of an EVA material approximately 6.5 mm thick with a durometer of approximately 25-45 Shore C and, more particularly, approximately 30-40 Shore C. Preferably, the front protuberance 32 includes diagonal notches 66, as shown in figures 1 and 5. The notches 66 have an angle corresponding to the articulation line of the joints in the metatarsal eminence of the foot, to increase the flexibility of the protuberance front 32. During the heel lift, the first metatarsal bone flexes down naturally. Preventing this natural flexion down the first metatarsal bone, causes the arch of the foot to flatten and the foot to suffer excessive pronation, increasing the tension exerted on the ankles and knees. To adapt to downward bending, the medial portion 62 of the forward boss 32 extends rearward toward the corresponding concave portion 64 of the stability support 24. The shape of the stability support and the forward boss allows the first metatarsal bone flex more naturally, thus stimulating the loading of the big toe during the lifting of the heel. The valgus pad 34 is located below the toes on the lateral part of the foot. Preferably, the valgus pad 34 is firmer than the base 22, to further stimulate the loading of the big toe during the heel lift. For example, the valgus pad 34 may comprise a 1.5 mm layer of EVA with a durometer of approximately Shore C 70. In a preferred embodiment, the base 22 is covered with the top sheet 36 which is preferably a layer of non-woven material with a low coefficient of friction, so as to minimize the possibility of blisters. In a preferred embodiment, the material is treated with an antibacterial agent which, combined with a moisture sweep, reduces the odor produced by bacteria and fungi. A series of air ports 66 extend through the topsheet 36, the base 22 and the front protuberance 32, to allow air circulation above and below the sole 20. Figure 11 illustrates the bones of the foot super-taxes through a bottom view of the sole of the present invention. In the heel of the foot is the calcaneus 70 and forward of the calcaneus is the talus 72. In front of the talus 72, on the middle side, there is the navicular bone 74 and in the lateral part the cuboid 76 is located. in front of the cuboid and the navicular bone are the cuneiform bones 78. In front of the cuneiform bones 78 and the cuboid 76 are the metatarsal bones 80A to 80E. The first metatarsal bone 80A is located on the medial side of the foot and the fifth metatarsal bone 80E is located on the lateral part of the foot. In front of the metatarsal bones are the proximal phalanges 82. In front of the proximal phalanges 82 are the middle phalanges 84 and at the end of each of the toes are the distal phalanges 86. In a first preferred embodiment of the present invention, the various components of a sole made in accordance with the principles of the present invention, are permanently fixed to the base 22 using a suitable means such as an adhesive. In an alternative embodiment of the present invention, at least some of the components and, in particular, the protuberances, are fixed to the base 22 so that they can be changed or replaced. For example, the protuberances 26 to 32 can be attached to the base 22 using hook and loop fasteners, a temporary adhesive or other removable attachment means. By providing a sole package that includes interchangeable components, an end user can tailor the sole to their specific needs or to a specific end use. For example, an end user who is susceptible to suffering from excessive pronation or who will walk with a particularly heavy backpack, I could select a middle heel protrusion that is somewhat firmer than that of a typical user. Although the present invention has been described in connection with preferred embodiments, the detailed description is not limiting of the invention and other modifications will be obvious to the person skilled in the art. For example, the illustrative embodiment of the invention described above is based on the need to control the excess of pronation. Therefore, the illustrative embodiment has a medial heel protrusion that is firmer than the lateral heel protrusion. However, the lack of pronation can be addressed using a softer middle heel protrusion. Similarly, the excess or lack of supination during heel lift can be addressed by changing the characteristics of either of the base 22, the front protuberance 32 and the valgus pad 34.

The present invention has been described in the context of providing a commercially available sole that can be made available for distribution to the general public. However, the same principles could be used by a podiatrist or other medical professional to design or create a sole to meet the needs of a specific patient. Therefore, an improved sole has been described. It will be readily apparent that the illustrative modality of a sole described in this way could be useful to protect the foot and control pronation during activities such as walking, walking carrying a backpack and the like. However, it will be understood that the components of the sole system can be modified to adapt to other activities or to control other types of foot movement. Therefore, the description provided herein, including the presentation of thicknesses, materials and specific properties of the sole components, is provided for illustrative purposes only and is not of a limiting nature, as well as that the invention is exclusively limited. by the appended claims.

Claims (20)

NOVELTY OF THE INVENTION CLAIMS

1. - A sole for use in a shoe, the sole comprising: a center having a shape that fits the inside of the shoe and that has an upper side and a lower side; a stability support arranged on the lower side of the center; and a first and second protuberances disposed from the lower part of the center, wherein the first and second protuberances have different material properties.

2. The sole according to claim 1, further characterized in that the first and second protuberances comprise protrusions arranged in a position below the lateral and middle sides of a heel.

3. The sole according to claim 2, further characterized in that the protrusion arranged below the middle side of the heel is made of a material that is firmer than the material of the protrusion on the side.

4. The sole according to claim 3, characterized in that the firmness of the protrusion of the lateral part is on the Shore C scale 45-50 and the firmness of the protrusion of the middle side is approximately Shore C 60 .

5. - The sole according to claim 3, characterized in that the firmness of the protrusion of the lateral part is on the Shore C scale 50-55 and the firmness of the protrusion of the middle side is within the scale of approximately Shore C 65-70.

6. The sole according to claim 3, further characterized in that the firmness of the protuberances is selected to control a pronation index.

7 '.- The sole according to claim 3, further characterized in that the firmness of the protuberances is selected based on a type of activity for which the sole is designed.

8. The sole according to claim 2, further characterized in that it comprises a half-foot protrusion disposed forward of the protrusion of the lateral heel and along a portion of the sole corresponding to the lateral side of the foot.

9. The sole according to claim 8, further characterized in that the stability support has a shape that allows it to flex the first metatarsal bone during the lifting of the heel.

10. The sole according to claim 2, further characterized in that it further comprises a front protrusion arranged below the center in the portion of the sole corresponding to the metatarsal eminence of the foot.

11. - The sole according to claim 10, further characterized in that the stability support and the front protrusion have a shape that allows them to flex the first metatarsal bone during the lifting of the heel.

12. The sole according to claim 2, further characterized in that it additionally comprises a pad disposed from the sole in a region corresponding to the valgus.

13. The sole according to claim 1, further characterized in that the center comprises an EVA foam material.

14. The sole according to claim 1, further characterized in that the protuberances are fixed removably to the center.

15. The sole according to claim 1, further characterized in that the protuberances comprise a polyurethane material fixed to the center with a temporary adhesive.

16. The sole according to claim 1, further characterized in that the protuberances comprise a polyurethane material fixed to the center with a hook and loop fastener.

17. A method for protecting and controlling the movement of a foot in a shoe, the method comprising: providing a center that has a shape that fits the inside of the shoe and that has an upper side and a lower side; provide stability support arranged on the bottom side of the center; providing a first protrusion disposed from the lower part of the center in a region corresponding to the lateral portion of the heel; and providing a second protrusion disposed from the lower part of the center in a region corresponding to a middle portion of the heel, wherein the first and second protuberances have different properties of materials selected to control the movement of the foot.

18. The method according to claim 17, further characterized in that it further comprises providing a third protrusion disposed from the bottom of the center forward of the first protrusion in a region corresponding to a lateral portion of the foot.

19. The method according to claim 18, further characterized by additionally comprising providing a fourth protrusion arranged from the bottom of the center forward of the third protrusion in a region corresponding to the metatarsal eminence of the foot.

20. A sole for use in a shoe, the sole comprising: a center that has a shape that fits the interior of the shoe and that has an upper side and a lower side; a top sheet disposed from the upper side of the center; a stability support arranged on the lower side of the center; a first plurality of interchangeable protuberances with different firmness and adapted to be disposed from the side of the lower part of the center in a region corresponding to the lateral portion of the heel; and a second plurality of interchangeable protuberances with different firmness and adapted to be disposed from the side of the lower part of the center in a region corresponding to the median portion of the heel, wherein the first and second protuberances may be selected from the first and second pluralities of protuberances, respectively, and arranged from the side of the lower part of the center.