Patent Application
20150040433
This application claims the benefit of priority under 35 U.S.C. ยง119 of German Patent Application DE 10 2013 215 776.2 filed Aug. 9, 2013, the entire contents of which are incorporated herein by reference.
The invention relates to an orthopedic shoe for preventing excess pressure loads on pressure-sensitive foot soles, in particular the foot soles of diabetics. The shoe has a rigid sole with a toes area and/or heel area having a convexly rounded sole portion and having a shaft and with a fixation device, provided on the shaft, having a heel strap extending from the left instep across the back of the heel bone to the right instep, with a dorsal strap extending across the dorsum of the foot and a pulling device which can be tensioned across the dorsum for size adjustment.
Orthopedic shoes of this kind can be used in particular, but by no means exclusively, in the treatment of diabetics. The shoes according to the invention are suitable for treating pressure-sensitive foot soles in general. For diabetics, however, prevention of excess pressure loads on the feet is of enormous therapeutic importance.
On average, one in five people in the age group between 20 and 70 require treatment for vein problems or suffer from pathological venous changes that cause symptoms and for which treatment may become necessary. The cause for this is commonly an oftentimes major weakness of the connective tissue leading to a weakening of the venous walls and thus to insufficient closure of the venous valves. This causes a reduction of the venous return from both legs into the body.
In Germany alone, there are about 5 million diabetics among whom a so-called diabetic foot is prevalent in a more or less pronounced manner. In consequence, this means that open wounds may develop on the foot sole of the forefoot which often become infected and many times end in amputation of the foot. The causes of the diabetic foot lie in stenoses and potential occlusions of larger arteries and smaller arterial capillaries occurring in the arterial vascular system because of the diabetic metabolic state. As a result, the tissue, in particular the skin, is no longer supplied with a sufficient amount of oxygen and partially dies off, leading to open areas of skin Owing to the reduced function of the arterial capillaries in particular, the skin nerves are no longer properly supplied and a diabetic polyneuropathy develops. This means that the patients lose sensitivity in the malnourished area of the skin, accompanied by a significantly reduced sensitivity to pain, so that anatomically predicted pressure points are no longer registered and the skin is basically damaged without pain. Since the patients feel no pain in the overstrained areas of the skin, the damage to the skin is oftentimes not noticed at all or, in any case, far too late.
From DE 10 2010 022 329 A1, a generic shoe with a rigid sole and convexly rounded sole portions is known, which is of the type that can be worn in particular by diabetics. For fixing the foot in the shoe, the fixation of the heel area in particular is of highest importance in generic shoes because the foot substantially does not roll during walking owing to the rigidity of the sole. Instead, the shoe rolls on the rounded sole portions, the rear part of the sole having to be lifted with respect to the rolling point beneath the ball of the foot when walking forward. When the rear portion of the sole is lifted in this manner, significant forces are active between the fixing means of the shoe on the one hand and the foot on the other hand so as to prevent the heel from wobbling in the shoe. Such wobbling of the heel in the shoe would cause undesired relative motions of the foot with respect to the inner side of the sole, which might cause injuries and wounds.
For fixing the heel in the shoe, DE 10 2010 022 329 A1 proposes a Y-shaped insert whose lower end is attached to the sole and whose two upper branches span across the heel on the one hand and the dorsum of the foot on the other hand. This Y-type fixation means has proved to be poorly suitable for a fixation of the foot in the shoe with as little play as possible. This is in particular because no sufficient tightening pressure can be applied in the area of the heel when tightening the fixation means so that the heel starts to slightly wobble in the shoe. If the support pressure in the area of the dorsum of the foot is excessively increased to compensate the insufficient pressure in the area of the heel, wearing comfort is reduced and undesired blood congestions may also occur.
Starting from this state of the art, it is therefore an object of the present invention to provide a new orthopedic shoe that can be adapted to different foot shapes in the area of the heel so as to reduce or entirely prevent excess pressure loads on pressure-sensitive feet.
According to the invention, an orthopedic shoe is provided for preventing excess pressure loads on pressure-sensitive foot soles. The orthopedic shoe comprises a rigid sole which substantially precludes bending of the forward joint of the foot during walking, the sole having, in a toes area and/or in a heel area, a convexly rounded sole portion which allows the rigid sole to roll. The shoe further comprises a shaft and a fixation means, provided on the shaft, for fixing the foot in the shoe, the fixation means having a heel strap which extends from a left instep across a back of a heel bone of the foot of wearer to a right instep, the fixation means comprising a dorsal strap extending across a dorsum of the foot and a pulling means that is tensionble across the dorsum for size adjustment. The dorsal strap is attached, in a load-transmitting manner, with a left and a right connecting element to a heel strap left portion and a heel strap right portion of the heel strap. The connecting elements each have a distance to two ends of the heel strap attached laterally to the shoe and a distance to a center of the heel strap spanning across the heel bone.
The shoe according to the invention is based on the idea that fixation means comprise a heel strap which extends from the left instep across the back of the heel bone to the right instep, and comprise the dorsal strap which extends across the dorsum of the foot and has a pulling means. According to the teaching of the invention it is provided that the dorsal strap is attached in a load-transmitting manner with a left and a right connecting element to the left and right portion of the heel strap, the connecting elements each having a distance to the two ends of the heel strap arranged laterally on the shoe and to the center of the heel strap spanning across the heel bone. By means of such a fixation means, it is possible to optimally fix the heel of the foot to the sole of the shoe according to the invention. This is because the tensioning forces are transmitted at the connecting elements in a load-transmitting manner into the two portions of the heel strap when the pulling means of the dorsal strap is tensioned for size adjustment. Since the two ends of the heel strap are attached to the shoe, the tensioning forces transmitted into the heel strap at the connecting elements cause a pulling force to act on the center of the heel strap spanning across the heel bone. Thus, the heel strap applies itself in a form-fitting manner around the heel of the foot and fixes the heel in the shoe by means of a form fit. The tensioning force applied to the heel by the heel strap can be adjusted by the user by varying the tensioning force exerted by the pulling means. Owing to the form-fit adjustable in its tension between the heel strap on the one hand and the heel of the user on the other hand, an optimal fit is set, which prevents the heel from slipping out with respect to the sole. Thus, when walking forward, the heel remains fixed in a substantially play-free manner in the shoe also during rolling of the rigid sole and undesired relative motions between the sole of the foot and the inner sole of the shoe are minimized or entirely precluded.
The arrangement of the two connecting elements, at which the pulling forces are transmitted into the heel strap, relative to the center of the heel strap spanning across the heel bone on the one hand and to the two ends of the heel strap fixed laterally to the shoe on the other hand is of great significance with regard to an optimal adjustment of the fit of the shoe in the area of the heel. This is because the mechanical leverage and pulling ratios change depending on the arrangement of the two connecting elements on the heel strap. It has proven particularly advantageous in this context that, in the direction of the longitudinal axis of the shoe, the connecting elements each are arranged between the center of the heel strap spanning across the heel bone on the one hand and the two ends of the heel strap attached laterally to the shoe on the other hand. This means in other words that, when viewing the shoe in the lateral profile, the connecting elements are arranged between the back of the heel on the one hand and the two attachment points of the heel strap on the other hand. The heel strap can extend straightly or slightly curved between the two attachment points on the one hand and the center of the heel strap spanning across the heel bone on the other hand By arranging the connecting elements between the center of the heel strap on the one hand and the ends of the heel strap on the other hand, it is achieved that, when the pulling means is tensioned, the heel strap pulls the two connecting elements of the two lateral portions of the heel strap out of its straight or slightly curved shape in the direction of the dorsum of the foot and in doing so, high attachment forces can be applied at the heel strap under relatively low adjusting forces on the pulling means owing to the pulling and leverage ratios. For the user, this means a high ease of use because he/she only needs to apply relatively low forces at the pulling means of the dorsal strap to tension the heel strap.
As described before, the two lateral portions of the heel strap are pulled together and upward in the direction of the dorsum of the foot when the pulling means is tensioned and the center of the heel strap is thus tensioned forward in the direction of the toes. This adjusting motion of the heel strap causes a slight relative rotation of the heel strap about the attachment point in the area of the attachment points on the two lateral ends of the heel strap. This slight rotation can be compensated by a deformation of the heel strap in the area of the attachment points, given a sufficiently elastic material. In that case, however, the user has to apply an additional tensioning force to elastically deform the heel strap in the area of the two attachment points. To avoid this additional tensioning force, it is therefore particularly advantageous if the two ends of the heel strap are attached to the sole in pivot bearings. For this purpose, the two ends of the heel strap can be riveted to the sole with a fixing rivet, for example. The pivot bearing permits a substantially force-free rotation of the ends of the heel strap about the attachment point, wherein, at the same time, the necessary tensioning forces can be transmitted into the sole via the pivot bearing.
The shaft of the shoe according to the invention is intended to fix the foot on the sole of the shoe. To this end, the shaft of the shoe surrounds the top side of the foot at least in sections. For example, the shaft can be composed of various bands, an open shoe, e.g. a sandal, thus being formed. Alternatively or additionally, the shaft can comprise a shell made of a supple upper material. Said upper material may be synthetic materials, such as Gore-Tex textile material, or leather. The upper material then covers the foot at least in sections and increases the wearing comfort. For the shoe according to the invention, it is provided in this context that the heel strap extends at the outer side of the shell.
If the shoe according to the invention is equipped with a shell made of a supple upper material, it is advantageous if the heel strap is not connected to the shell in the left and right portion between the center of the heel strap spanning across the heel bone on the one hand and the two ends of the heel strap arranged laterally on the shoe on the other hand, but instead extends freely across the supple upper material. Due to the fact that the heel strap on the one hand and the shell on the other hand are not connected to each other, in particular not sewn together, the heel strap can be freely repositioned across the upper material of the shell when the pulling means on the dorsal strap is tensioned so that the upper material is not deformed in spite of the adjustment of the heel strap and a formation of folds is avoided.
Further, it is particularly advantageous if the center of the heel strap spanning across the heel bone is not connected to the shell made of a supple upper material, either. As a result, the heel strap is then directly connected to the shoe, in particular to the sole of the shoe, only at the two ends. All other parts of the heel strap can be repositioned freely across the supple upper material of the shell and thus realize an optimal form fit between the heel strap on the one hand and the heel on the other hand To fix the height of the center of the heel strap in the area of the heel relative to the shell, a flap protruding upward can be provided on the shell. The heel strap then extends across the attachment area of the flap protruding upward so that the heel strap is precluded from slipping downward too far.
To be able to easily transmit the necessary forces in the heel strap of the shoe according to the invention, the heel strap should be produced from a mechanically sufficiently stiff material, such as a plastic hoop of suitable thickness. However, such a heel strap made of a material of increased stiffness has the disadvantage that the heel strap exhibits significant resistance against its deformation in the point of articulation of the two connecting elements during tensioning of the heel strap because the rigid material must be elastically deformed at least slightly in the point of articulation of the connecting elements. To avoid these undesired counterforces, which are necessary for deforming the heel strap in the area of the points of articulation of the two connecting elements, it is particularly advantageous if the heel strap has a material weakening, in particular a wedge-shaped indentation, in the area of the points of articulation of the two connecting elements. By means of this material weakening, the stiffness of the heel strap can be reduced transversally to its longitudinal axis in the area of the points of articulation of the two connecting elements so that the resistance of the heel strap against deformation during tensioning of the heel strap is reduced.
The structure of the sole of the orthopedic shoe is basically optional as long as on the whole the sole has sufficient rigidity and the motion of the foot while walking therefore does not exceed a tolerable degree. To be able to ensure high walking comfort in addition to the necessary rigidity, it is particularly advantageous if the sole comprises an outer sole and an inner sole made of different materials. The outer sole can then be produced from an elastically damping material so as to realize the desired walking comfort. The inner sole is produced from a rigid material. The rigidity of the inner sole can then be selected high enough, irrespective of the material of the outer sole, for the sole at large to have the rigidity necessary for use on an orthopedic shoe.
Many users require use of the orthopedic shoe on only one foot because the second foot is not pathologically altered. This fact, however, significantly increases the necessary production costs because the users only require one shoe, while the manufacturer has to provide shoes both for the left and for the right feet in different shoe sizes. To be able to reduce the necessary number of varieties and the accompanying production costs, it is therefore particularly advantageous if the inner side of the sole and of the shaft facing the foot is formed axially symmetric with respect to the longitudinal axis of the shoe. This axial symmetry of the inner side of the shoe makes it possible to wear the shoe optionally on the left or on the right foot. For supplying the different users, all that is required then is to offer the shoe in different shoe sizes, the shoe then being wearable optionally on the left or on the right foot.
The type of pulling means with which the shoe according to the invention is fixed on the foot of the user is basically optional. Preferably, the pulling means can be formed in the manner of a tension strap. Said tension strap is fixed with one end, namely the fixing end, on the one side of the dorsal strap. On the opposite side of the dorsal strap, a deflection loop is attached, in which the tension strap can be deflected starting from its fixing end and in doing so spans across the dorsum with variable length. On the free end of the tension strap, a hook or loop tape is provided, which, following the adjustment of the necessary tensioning length of the tension strap, is placed on a hook or loop tape provided in the area of the fixing end and is thus fixed.
If the shoe according to the invention is designed to be axially symmetric and can be worn optionally on the left foot or on the right foot, it is particularly advantageous if the fixing end and the deflection loop of the tension strap are fixed in a detachable manner by means of respective coupling means. By alternately detaching the coupling means on the fixing end and on the deflection loop, the arrangement of the fixing end on the right or left side of the shoe can be changed. As a result, it is possible to provide for the free end of the tension strap to run from the inside to the outside in each case despite the axially symmetric design of the shoe by re-plugging the two coupling means. This means in other words that by re-plugging the coupling means of the tension strap, an adjustment can take place to the effect that the shoe can be worn on a left foot or on a right foot.
To be able to fix the hook tape of the pulling means in an adjustment area as large as possible, it is particularly advantageous if the hook tape or loop tape of the hook and loop fastener on the fixing end of the tension strap covers the outer side of the coupling means associated with the fixing end.
The shoe according to the invention can be preferably combined with an orthopedic inner shoe sole. Preferably, the inner shoe sole has a pad distributing pressure peaks in the space between the top side and the bottom side of the inner shoe sole, namely in the area beneath the forefoot joint, the deformable pad casing of said pad being filled with deformable filling bodies which are mobile relative to one another. A pad of this kind with a deformable pad casing and filling bodies contained therein which are deformable and mobile relative to one another allows the shape of the pad to consistently adapt to the changing shape of the foot sole in the area of the forefoot joint. This is because the shape of the pad is determined by the arrangement of the mobile filling bodies in the pad casing. If now the shape of the foot sole or the position of the foot sole on the inner shoe sole changes, the shape of the pad can be easily adapted to this change by shifting of the mobile filling bodies. The shifting of the filling bodies continues until largely complete pressure compensation is achieved. This means in other words that the filling bodies are shifted in the pad casing until the shape of the pad optimally fits the shape of the foot sole again and thus all pressure peaks between the foot sole and the inner shoe sole have been largely dissipated or entirely eliminated. During the subsequent wearing of the inner shoe sole, the deformability of the filling bodies or rather the deformability of the pad casing provides optimal damping. The shifting of the filling bodies in the pad casing to a certain degree also causes a type of massaging motion of the inner shoe sole on the skin of the foot sole, which stimulates blood circulation. This in turn has a positive effect with regard to avoiding open areas on the skin of the foot sole of diabetics.
To enable an optimal shape adaptation of the pad filled with the mobile filling bodies to the shape of the foot sole, it is required that no air pockets form inside the pad casing. Such air pockets would move within the pad casing as a function of the pressure load and would thus continuously change the pressure state and cause undesired pressure peaks. According to a preferred embodiment of the inner shoe sole according to the invention, it is therefore provided that the pad casing has at least one deaeration opening through which the air present in the pad can escape to the outside when pressure is applied. As a result, the deaeration opening ensures that complete pressure compensation takes place between the inside of the pad casing and the ambient atmosphere. The formation of undesired air pockets within the pad casing is thereby avoided.
To be able to at least temporally fix the shape of the pad filled with the filling bodies, an evacuation device may be provided on the pad casing. By means of this evacuation device, the air present in the pad casing can be evacuated to a point where negative pressure forms in the pad casing. This negative pressure pulls the deformable pad casing against the deformable filling bodies and thus the relative position between the individual filling bodies is fixed. By ventilating the evacuation device, the negative pressure can be released from the pad casing and a new shape of the pad can be adjusted by shifting of the filling bodies in the pad casing.
The adjustment of the shape of the inner shoe sole by shifting of the mobile filling bodies present in the pad casing is based on the shifting of the filling bodies upon loading. In that course, filling bodies in the area of high pressures are shifted into areas of lower pressures until all areas of the foot sole exhibit a substantially similar pressure load. Owing to the anatomic deformation of the foot sole and the respective accompanying pressure load, very long shifting paths may occur in the shifting of the filling bodies, which cannot be traveled within a reasonable time anymore. In particular if the entire foot sole is to be supported by a single pad casing and the mobile filling bodies contained therein, very long shifting paths may occur so that a reformation of the pad within reasonable time frames cannot be expected. To avoid such shifting paths of inacceptable length and to be able to adapt the pad geometry specifically to the different areas of the foot sole, it is particularly advantageous if the pad is divided into at least two pad segments. The shape of the individual pad segments and in particular the filling level of the individual pad segments can then be adapted to the respectively different requirements in the different areas of the foot sole.
The number of pad segments and the areas of the foot sole in which they are arranged are basically optional. According to an advantageous embodiment, it is provided that a pad segment is arranged on the one hand in a manner according to the invention in the area of the forefoot joint of the foot and/or in the toe area of the foot and/or in the area of the metatarsus and tarsus of the foot and/or in the heel area of the foot. In particular, an embodiment version with a total of four pad segments in the toe area and in the area of the forefoot joint area and in the area of the metatarsus and tarsus and in the heel area is especially advantageous.
A rolling motion of the inner shoe sole occurs in the shoe during the walking motion of a user of the orthopedic inner shoe sole. This rolling motion of the inner shoe sole may cause undesired shifting effects of the filling bodies in the pad casing. To minimize these undesired shifts, it is particularly advantageous if a spacing groove is arranged between adjacent pad segments. Said spacing groove allows a relative motion of the adjacent pad segments when the inner shoe sole is rolling during walking and thus minimizes the shifting effect on the mobile filling bodies in the individual pad segments.
With regard to a strongest possible minimization of the undesired shifting effect caused by the rolling motion of the inner shoe sole, it is particularly advantageous if the spacing groove between adjacent pad segments extends in a curved shape along its longitudinal axis. The curve of the curved spacing groove should extend in a concave manner around the heel of the inner shoe sole and thus point with its center portion in the direction of the forefoot.
If the inner shoe sole has several pad segments, it may be desirable to have the filling bodies travel variably between the individual pad segments so as to be able to vary the filling level of the individual pad segments, for example. In this way, it is in particular possible to adapt the properties of the inner shoe sole to the requirements of different users. To realize this kind of adaptation of the inner shoe sole according to the invention, it is provided according to a preferred embodiment that the pad segments are formed to be at least partially communicative, air and/or filling bodies being able to pass through at least one passage opening between two communicating pad segments. By shifting the bodies through the passage openings, the filling level of individual pad segments can be varied and changed. Moreover, air can be conveyed through the passages between the individual pad segments so that in particular not every single pad segment must have a deaeration opening and/or an evacuation device.
To avoid shifting of filling bodies between the communicating pad segments during the use of the inner shoe sole, it is particularly advantageous if the cross-section of the passage opening is selected appropriately relative to the cross-section of the filling bodies. The cross-section of the passage opening should be at least large enough relative to the cross-section of the filling bodies for the filling bodies to pass through the passage opening between the communicating pad segments in the unloaded state. At the same time, the cross-section of the passage opening should be small enough relative to the cross-section of the filling bodies that the filling bodies cannot be shifted through the passage opening in the loaded state of the inner shoe sole.
To provide wearing comfort and a transition that is as free of pressure peaks as possible in particular in the area of the spacing grooves, it is particularly advantageous if an additional elastic pressure distribution layer, in particular made of foamed material, is arranged on the side of the inner shoe sole facing the foot. Since this additional pressure distribution layer only has to cushion small pressure peaks, it can be formed correspondingly thin and is not subject to the otherwise occurring signs of wear and to the accompanying undesired impression in the inner shoe sole.
An embodiment of the invention is schematically illustrated in the drawings and will be explained in the following by way of example. The various features of novelty which characterize the invention are pointed out with particularity in the claims annexed to and forming a part of this disclosure. For a better understanding of the invention, its operating advantages and specific objects attained by its uses, reference is made to the accompanying drawings and descriptive matter in which preferred embodiments of the invention are illustrated.
In the drawings:
Referring to the drawings in particular,
Respective pulling means 09 and 10 are provided on the front fixation means 06 and on the rear fixation means 07 to allow the user to adjust the size of the shoe 01 to his/her individual requirements. By way of the pulling means 09, the front portion of the shoe 01 is fixed in the area of the forefoot, whereas by means of the pulling means 10, a size adjustment in the area of the metatarsus and the heel is possible. The two pulling means 09 and 10 each are formed as tension straps which have a loop and hook fastener on their inner side, by means of which they allow a size adjustment of the pulling means 09 and 10.
The rear fixation means 07 in its basic structure is composed of a heel strap 11 and a dorsal strap 12 attached thereto. The dorsal strap 12 can be tensioned with variable length across the dorsum of the user's foot by way of the pulling means 10. The pulling means 10 forms an integral part of the dorsal strap 12. The heel strap 11 extends starting from its first end 13, which is attached with a fixing rivet to the sole 02 (fixing rivet 14 and end 13 illustrated in hidden manner in
As can be seen in
The coupling means 25 is attached to the fixing end 26 of the pulling means 10. For use of the pulling means 10, after the coupling means 25 is fixed to the first deflection loop 23, the pulling means 10 is threaded with its free end 27 through the second deflection loop 24 and is guided back to the fixing end 26. A hook and loop fastener with a loop tape and a functionally complementary hook tape is provided on both sides of the pulling means 10 so that the tension length of the pulling means 10 can be fixed by placing the hook tape on the loop tape.
In
The coupling means 25 allows attaching the pulling organ 10 with its fixing end 26 optionally to the first deflection loop 23 or to the second deflection loop 24. Since the shoe 01 is otherwise formed to be completely axially symmetric with respect to its longitudinal axis and thus can be worn optionally on the left or on the right foot with equal function, the optional attachment of the fixing end 26 to the first deflection loop 23 or the second deflection loop 24 allows a side-specific appearance of the shoe 01. The versions illustrated in
The structure of the pad 104 with the four pad segments 105 to 108 can be taken from the longitudinal section according to
The spacing grooves 113 to 115 each extend in a curved shape concavely around the heel of the inner shoe sole 101. The passages 111 between the adjacent pad segments 105 to 108 each extend transversally to the spacing grooves 113 to 115. By arranging the deaeration openings 120 at the side of the passages 111 facing the bottom side 103, it is ensured that the deaeration openings 120 are not closed even if the inner shoe sole is loaded because the passages 111 are arranged in a retreating manner with respect to the bottom side 103 within the spacing grooves 113 to 115.
The pad segments 105 to 108 of the inner shoe sole 101 are formed by two layers 116 and 117 made of a PU film. The layer 116 has a substantially plane layout. In contrast, the layer 117 is formed three-dimensionally, by deep-drawing of the PU film, for example, and forms four chambers 118 corresponding in their form to the pad segments 105. When producing the inner shoe sole 101, first, the three-dimensionally molded layer 117 is filled with the filling bodies 110 and then the layer 116 is sealed to the layer 117 in the contact areas. By sealing the two layers 116 and 117, the chambers 118 with the filling bodies 110 contained therein are closed. To ensure a pressure distribution as free of pressure peaks as possible for the user also in the area of the spacing grooves 113 to 115, at last, a pressure distribution layer 119 made of foamed material is applied to the top side of the layer 116.
While specific embodiments of the invention have been shown and described in detail to illustrate the application of the principles of the invention, it will be understood that the invention may be embodied otherwise without departing from such principles.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10 2013 215 776.2 | Aug 2013 | DE | national |
