JPH08322864A - Artificial leg for leg - Google Patents

Abstract

PURPOSE: To provide a practicable artificial leg for the leg having elasticity and high fatigue strength. CONSTITUTION: This artificial leg has an internal skeletal member 1 carrying load and sheath members 2, 3 enclosing this internal skeletal member 1 with the shape simulating the foot and the leg. The member 1 consists of a lower leg strut 4 having the rigidity of the lower leg bone and a foot core material 5 having the rigidity of the locally deformable foot bones. This foot core material 5 includes a hollow core member 6 which has the high rigidity to shape the foot part, a toe tip elastic plate 7A which is fixed to the position corresponding to the main joints of the foot fingers of a foot rear plate part 10 of this core member, is disposed to extend below a foot end curved plate part 8 and is deformable in the bending direction of the toe tips and a heel elastic plate 7B which is fixed to the position on the lower extension of the lower leg strut 4 of the part 10, is disposed to extend below the heel curved plate part 9 and is deformable in a warping direction. Limiting elements for limiting the curving when the rear surface part 8A of the foot end curved plate part and rear surface part 9A of the heel curved plate part of the core member 6 are bent respectively to an arc shape and when the toe tip elastic plate 7A and the heel elastic plate 7B are warped upward to respectively specified values are formed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates generally to a foot prosthesis, and more particularly to a lower leg prosthesis for the lower leg and lower leg from the knee.

[0002]

BACKGROUND OF THE INVENTION There are many types of devices in the prior art for solving problems with foot prostheses. Since this type of lower leg prosthesis does not include a knee joint, its main function is basically to support vertical load, and rod-shaped or pipe-shaped ones were used as simple structures. Has led to the development of artificial legs whose heels and toes have elasticity and deformability similar to those of actual humans.
There are various prior arts, but basically they are roughly classified into the following two types.

The rear part of the toe corresponding to the main joint of the toe is basically hard, and the toe part from there is wrapped with a material having an appropriate elasticity, for example, a rubber material. The form (for example, JP-A-5-123348,
-344994 gazette). In the case of this prior art, it is possible to rotate in the vertical warp direction at the position of the main joint of the toe, and the appropriate rotation resistance can be obtained by the deformation of this material, so that it is possible to expect a smooth walking near the actual deformation behavior of the foot. . , "Resilient plate" with a certain elasticity up to the tip of the toe, which corresponds to the bone of the toe
Is a type introduced into a skeletal member (see Japanese Patent Laid-Open Nos. 4-285551 and 5-285166). Since this type does not change its rigidity rapidly from the heel to the toes,
At the position of the main joint of the toe, there is an advantage that fatigue destruction is less likely to occur.

[0004]

In the case of the prior art of [Problems to be Solved by the Invention],
There is a problem that a material which forms a generally soft portion having elasticity is easily fatigue-fractured at a boundary between a hard material and a toe main joint end portion and has a short service life. On the other hand, in the case of the prior art of (1), the elastic plate as a whole has an average rigidity with the hard part of the central part, which makes it difficult to rotationally deform at the toe joints of the fingertips, making it smoother than I cannot get a good walking interval. Therefore, this type of product has a problem in use which is limited to the type that exercises violently.

The present invention has been made to solve such problems, and an object of the present invention is to provide a practical leg prosthesis having both elasticity and high fatigue strength close to those of an actual foot. Is to provide a simple structure at low cost. In addition, the elasticity close to the actual foot here means that the toes are deformed so as to bend around the toe main joint position as the weight moves forward in the walking motion, but with respect to this bending Of course, it is necessary to have appropriate resistance and bending angle corresponding to the reaction force from the ground.

[0006]

The present invention has the following configuration to achieve the above object. That is, the present invention provides a lower leg artificial leg that includes an internal skeleton member that bears a load, and an outer covering member that surrounds the internal skeletal member in a shape that simulates the foot and the lower leg. It consists of the lower leg support with the rigidity of and the foot core material with the rigidity of the locally deformable foot bone.
A toe bending plate portion, a heel bending plate portion, a sole plate portion connecting the lower end portions of both bending plate portions to each other, and a foot plate portion and an ankle plate portion that also connect the upper end portions of both bending plate portions to each other. A high hollow core member, a toe elastic plate that is attached to the sole plate portion of the hollow core member and extends below the toe bending plate portion and is deformable in the bending direction of the toe, and also the sole plate portion. A heel elastic plate which is attached to the lower part of the heel curved plate part and is deformable in a warp direction provided below the heel curved plate part, the toe elastic plate being fixed to the sole plate part at a position corresponding to the main joint of the toe. Is formed at a free end portion capable of coming into contact with and separating from the curved tip of the foot, and the heel elastic plate is fixed to the sole plate portion at a position on a downward extension of the lower leg support portion of the ankle plate portion. It is characterized in that the rear end side is formed as a free end that can come in contact with and separate from the heel curved plate part. A thigh prosthesis.

According to the present invention, in the lower leg prosthesis having the above structure, the lower surface portion of the tip curved plate portion and the lower surface portion of the heel curved plate portion are bent in an arc shape, and the lower surface of the toe elastic plate and the heel elastic plate are both lower surfaces. A lower leg prosthesis characterized by forming limiting elements for limiting the amount of upward bending in the direction approaching the respective parts to a fixed value, and the elastic plate of the toe and elastic plate of the heel are integrated. It is a lower leg prosthesis characterized by comprising a single plate.

According to the present invention, in the lower leg prosthesis having the above-mentioned structure, the free end portion of the tip elastic plate and the rear free end portion of the heel elastic plate are the tip portion of the tip bending plate portion and the heel bending plate portion. A lower leg prosthesis characterized by being positioned at substantially the same level in the longitudinal direction of the prosthesis with respect to the rear end portion, and the internal skeletal member is made of fiber reinforced plastic, and its rigidity and elasticity are thick or fibrous. A leg prosthesis characterized by being adjusted by adjusting a volume ratio, and further, reinforcing fibers in a fiber reinforced plastic forming an elastic plate of a toe and an elastic plate of a heel are mainly oriented in a plate longitudinal direction perpendicular to a bending direction. It is a lower leg prosthesis characterized by being provided.

[0009]

According to the present invention, the lower leg prosthesis is provided with the internal skeleton member and the outer covering member surrounding the lower limb prosthesis, and the internal skeleton member invisible from the outside supports the load, so that there is no restriction on the appearance. It is possible to employ a structure and material that have the required deformability and have a high fatigue strength. on the other hand,
The outer member that carries the appearance deforms following the large deformation of the heel and toe, but because it can be formed relatively thin due to the relationship with the shape of the internal skeleton member, the stress that occurs even if it is greatly deformed Low, no fatigue failure. Further, the internal skeleton member is divided into a hollow core member of a rigid body portion that does not deform by supporting a load and a toe elastic body plate and a toe elastic plate of an elastic body portion that positively deforms in response to an external force. Due to the structure, elasticity can be imparted to the toes and the heel independently of each other.

Further, according to the present invention, the elasticity of the artificial leg is changed at the position of the toe main joint by attaching the elastic plate of the toe to the sole plate portion of the rigid portion at the position corresponding to the toe main joint of the toe. And the elasticity before that can be made closer to that of the actual foot. Similarly, with respect to the heel portion, by attaching the heel elastic plate to the sole plate portion at a position on the extension of the lower leg support corresponding to the lower leg bone, elasticity close to that of the actual deformation of the heel portion of the foot can be obtained.

According to the present invention, in the lower leg prosthesis, the lower surface portion of the toe bending plate portion and the lower surface portion of the heel bending plate portion are bent in an arc shape, and the toe elastic plate and the heel elastic plate are bent upward. By forming a limiting element to limit the amount of each elastic plate to a constant value, the amount of deformation of both elastic plates is kept constant at the rigid parts, so that even if an excessive load acts on the prosthesis, their elasticity is reduced. Prevents static breakage of plates and also avoids fatigue breakage. To further explain this point, if a means for suppressing the amount of deformation of both elastic plates to a constant value at a rigid portion is taken as described above, the bending rigidity of the foot portion of the artificial leg in the vertical direction at the toe main joint position of the toe is increased. Sudden change (when viewed from the heel, it becomes easier to bend vertically in the joint position). As a result, when the center of gravity of the body moves forward while the weight is still applied to the foot, the situation in which the foot is bent about the joint position is obtained. This is because the rigidity is sufficiently high on the heel side of the joint position, and on the other hand, the bending rigidity of the elastic plate is relatively thin on the toe side of the joint position.

Since this elastic plate has a certain bending rigidity at the same time, it resists bending. This resistance can be freely designed so as to be close to the actual bending resistance of the foot by adjusting the thickness and elastic modulus of the elastic plate. Furthermore, by limiting the bending amount (bending angle) of the elastic plate to a fixed value and setting an upper limit, the stress at the joint root portion where the bending stress becomes highest can be suppressed to a fixed value or less. This is because the maximum stress at that point is determined by the bending angle. Regarding this bending angle, it is necessary to bend to a value necessary for actual walking. Therefore, in order to keep the maximum stress at the bending angle below the fatigue strength of the material, the thickness is naturally limited. That is, as the thickness increases, the stress generated at the same bending angle increases, and it goes without saying that it is necessary to reduce the plate thickness in order to reduce the stress.

According to the present invention, the rigidity against bending can be dealt with by increasing the elastic modulus of the material when it is necessary to reduce the plate thickness. That is, since both elastic plates are formed of fiber reinforced plastic, the elastic modulus of the fiber reinforced plastic is determined by the orientation and content of the reinforcing fibers, so it is required while keeping the maximum stress at the time of maximum bending below a certain value. The bending rigidity can be secured. According to the present invention, the toe elastic plate and the toe curved plate portion of the rigid portion, and the heel elastic plate and the heel curved plate portion of the rigid portion are formed by making the portions that suppress the deformation amount of both elastic plates constant into an arc shape. Since the contact point is always tangential to the bending of the toes and heel, and the contact point moves according to the bending angle, the place where maximum stress occurs during the deformation process of the elastic plate moves, resulting in fatigue damage. Is dispersed in each part of the plate, and fatigue fracture is less likely to occur. In this respect, the fatigue strength is further improved by using the unidirectional fiber reinforced plastic for the elastic plate. This is because a thin plate is required to obtain the same rigidity, the maximum stress against bending can be reduced, and in addition, the fiber reinforced plastic itself is resistant to fatigue.

[0014]

Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 shows an internal perspective perspective view of a lower leg artificial leg according to an embodiment of the present invention, and FIG. 2 shows a perspective view of an internal skeletal member 1 of the lower leg artificial leg of FIG. 1, respectively. With reference to FIGS. 1 and 2, a lower leg prosthesis according to an embodiment of the present invention includes an inner skeleton member 1 and outer covering members 2 and 3 surrounding the inner skeleton member 1. The internal skeleton member 1 forms a skeleton body that bears a load such as a load, and has a rigid lower leg column 4 that substitutes for the lower leg bone, and a local portion such as a toe portion that substitutes for the foot bone. It is mainly composed of a rigid core material 5 which can be deformed. On the other hand, the foot jacket member 2 and the crus jacket member 3 are formed in a relatively thin jacket made of synthetic rubber, foamed plastic, or the like, and are made to imitate a human foot or crus. It has an outward appearance and surrounds and covers the foot core material 5 and the lower leg support 4.

The foot core material 5 includes a hollow core member 6 corresponding to a portion having a high rigidity as a whole foot portion, and a toe elastic plate 7A corresponding to an elastic and deformable portion as a toe portion. , A heel elastic plate 7B corresponding to a deformable portion having elasticity as a heel portion. In order to reduce the weight of each of these members, for example, those finished in a predetermined shape with a material formed by a pultrusion method using glass fiber reinforced plastic (GFRP) as a raw material are used.

The hollow core member 6 is a hollow short cylindrical body having a flat annular shape with a complicated vertical cross-section in the longitudinal direction corresponding to the front-back direction of the foot, and is a substantially horizontal V-shape located at the front part. Curved toe plate portion 8 having a shape, a substantially U-shaped heel curved plate portion 9 located at the rear portion, and the lower end portions of the curved plate portions 8 and 9 are connected between them in order to connect them. And a sole plate portion 10 having a flat plate shape, and a foot plate portion 11 and an ankle having a horizontal character provided so as to be connected between the upper end portions of the curved plate portions 8 and 9 to connect them to each other. And a plate portion 12. The hollow core member 6 can be easily molded into a complicated shape by manufacturing it by drawing as described above, and the hollow core member 6 is made of a long tubular material as shown in FIG. It is cut into pieces to obtain one having a predetermined shape. In this case, the plate thickness of GFRP was set to about 8 mm in order to increase the rigidity.

In the hollow core member 6, the lower surface portion 8 of the foot curved plate portion 8 and the heel curved plate portion 9 which is continuous with the sole plate portion 10.
A and 9A are bent in an obliquely upward arc shape in the toe curved plate portion 8 and in an obliquely rearward upward arc shape in the heel curved plate portion 9, respectively, and the toe elastic plate 7A and the heel elastic plate 7B are inverted upward. Limiting elements are formed to limit the respective bending amounts to constant values. In addition, 19 is a notch part provided corresponding to the clearance gap between a 1st toe and a 2nd toe.

The toe elastic plate 7A is formed into a predetermined shape by cutting it from a material composed of a long flat strip as shown in FIG. 3 (C) into an appropriate length. 10 is attached to the front end portion of 10 and fixed to the sole plate portion 10 by the fixing members 13A and 13B realized by, for example, rivets at the position (a) corresponding to the main joint of the toe. Is provided so as to extend below the lower surface portion 8A. The toe elastic plate 7A is provided such that its front end, which is a free end, is located at substantially the same level in the longitudinal direction of the artificial leg with respect to the tip of the toe curving plate 8.

On the other hand, the heel elastic plate 7B has substantially the same shape as the toe elastic plate 7A, and is cut to an appropriate length from a material made of a long flat strip as shown in FIG. 3 (C). A predetermined shape is formed, and this is attached to the rear end portion of the sole plate portion 10 by abutting, and realized by, for example, a rivet at a position (b) on the downward extension of the lower leg support 4 fixing portion of the ankle plate portion 12. It is fixed to the sole plate portion 10 by the fixing members 14A and 14B and is extended below the lower surface portion 9A of the heel curved plate portion 9. The heel elastic plate 7B is provided such that its front end, which is a free end, is located at substantially the same level in the longitudinal direction of the prosthesis with respect to the tip of the heel curved plate 9.

When pressure is applied from the lower surface side of the elastic plates 7A and 7B, the respective free ends are pushed up and deformed in the upward warp direction, and when the pressure is removed, the elastic plates 7A and 7B return to the original flat shape. It comes to be elastically restored, and has the elasticity to be deformable in the warp direction. Therefore, in consideration of having an average weight of 60 kg of a person wearing the artificial leg and having elasticity, the plate thickness is set to about 2.5 mm using GFRP, for example. However, in this case, the orientation of the reinforcing fibers in GFRP is made to coincide with the longitudinal direction of the prosthesis. In this embodiment, both elastic plates 7A and 7B are formed as an integrated single plate, but they are separately formed and separately fixed to the sole plate portion 10. Is also good.

The lower leg support 4 is composed of a column member 15, a lower connecting member 16 and an upper connecting member 17, and the column member 15 is a trough-shaped member having a U-shaped cross section orthogonal to its longitudinal direction. As shown in FIG. 3C, for example, a material having a predetermined shape is formed by cutting a material made of a long trough-shaped body made of GFRP having a thickness of 3 mm into an appropriate length. The lower connecting member 16 and the upper connecting member 17 are engaged with the lower end portion and the upper end portion of the column member 15, and are integrally fixed by a fixing member 18 realized by, for example, bolts and nuts. Is formed. The lower leg support 4 is fixed to the ankle plate portion 12 of the foot core member 5 via the lower connecting member 16 to be in an upright position, and is used as a substitute for the lower leg bone.
7 is adapted to fit the stump of the wearer.

As shown in the conceptual model diagram of FIG. 4, the artificial leg of the embodiment having such a structure has a hard portion L of the foot body, a hard portion M of the lower leg, a toe portion N having a spring, and a spring. A basic structure formed from a heel portion O having
When wearing the artificial leg and walking, when first landing on the heel to the ground, the elastic heel plate 7B contacts the ground from the tip side, and as the weight is added, the analysis chart of FIG. Deformation becomes large, and finally the heel curved plate part 9
The heel elastic plate 7B almost comes into contact with the heel elastic plate 7B, and the cushioning action is performed during that time. Then, when the load exceeds a certain level, the heel elastic plate 7B hits the heel curved plate portion 9, so that no further deformation occurs and no damage occurs. Here, if the rigidity of the heel elastic plate 7B is adjusted so that the heel elastic plate 7B contacts exactly at the time of maximum load during normal walking, a cushioning effect having stable fatigue fracture resistance can be obtained at all times.

On the other hand, when the weight moves to the toe in the latter half of one step of walking, the elastic plate 7A of the toe gradually deforms from the tip side, as shown in the analysis chart of FIG. The deformation becomes larger as is added, and finally, the heel elastic plate 7A almost comes into contact with the heel curved plate portion 9, and a necessary reaction force can be generated during that time. In this case as well, when the load exceeds a certain level, the toe elastic plate 7A hits the toe curving plate portion 8, so that further deformation does not occur and destruction does not occur. Here, if the rigidity of the toe elastic plate 7A is adjusted so that the toe elastic plates 7A are in contact with each other at the time of the maximum reaction force during normal walking, a cushioning effect with stable fatigue fracture resistance can be obtained at all times. In some cases, the elastic plates of the heel and the toe may have different thicknesses and elastic moduli.

In the embodiment according to the present invention described above, the bending strength, bending rigidity and fatigue strength required at the same time are obtained by using the bending reinforcement structure at the toe and the heel, and It is possible to retain a morphology close to that of the foot, and the experimental data according to this example are shown in FIGS. 7 and 8. This is a range in which a smooth walking sensation can be obtained for a kind of artificial leg, and in FIG. 7, the reaction force of the toe decreases with an increase in the bending angle because the weight acting with walking moves to other legs. This is because. The load acting on the toe elastic plate 7A is a part of the total load applied to the leg, and this changes according to the movement of the weight. Therefore, as the bending angle increases, more of the load acts on the toe elastic plate 7A, and the elastic bending is apparently performed with a small load.

As is clear from FIGS. 7 and 8, according to this embodiment, the average characteristics in the substantially central region in the shaded region can be obtained, and the smooth walking feeling and the fatigue strength can be improved. was gotten.

[0026]

As described above, according to the present invention, the heel portion and the toe portion are composed of the hollow core member having high rigidity and the elastic plate which can be elastically deformed. It has elasticity and deformability equivalent to that of a prosthesis, and moreover, fatigue failure due to frequent deformation is reliably prevented. Further, the present invention, by attaching the toe elastic plate to the sole plate portion of the rigid portion at the position corresponding to the toe main joint of the toe, to change the elasticity of the artificial leg at the toe main joint position,
The elasticity beyond that can be approximated to that of the actual foot. The same applies to the heel part. By attaching the heel elastic plate to the sole plate at a position on the extension of the lower leg column corresponding to the lower leg, elasticity close to the actual deformation of the heel part of the foot can be obtained. , You can get a smooth walking sensation that is close to the actual foot of a person.

Further, according to the present invention, the lower surface portion of the toe bending plate portion and the lower surface portion of the heel bending plate portion are bent in an arc shape, and the bending amounts of the toe elastic plate and the heel elastic plate are warped upward by a constant value. By forming a limiting element for limiting the elastic stress, the location of the maximum stress is moved during the deformation process of both elastic plates, and as a result, the fatigue damage is dispersed to each part of the plate and the fatigue fracture is less likely to occur. The effect of being able to further avoid fatigue failure is achieved by suppressing the amount of deformation of the elastic part to a constant value in a rigid portion and not causing static failure of those elastic plates even if an excessive load acts on the artificial leg. Further, according to the present invention, by forming the internal skeleton member from the fiber reinforced plastic, it is possible to provide a lightweight, low-cost prosthesis having high rigidity and particularly excellent bending rigidity.

[Brief description of drawings]

FIG. 1 is an internal perspective view of a lower leg artificial leg according to an embodiment of the present invention.

2 is a perspective view of the internal skeletal member 1 of the lower leg prosthesis of FIG. 1. FIG.

FIG. 3 is a perspective view showing a forming material of the internal skeletal member 1 in the lower leg artificial leg of FIG.

FIG. 4 is a conceptual model diagram of the lower leg prosthesis shown in FIG. 1 in comparison with the lower leg of a human.

FIG. 5 is an analysis diagram at the time of heel landing of the lower leg prosthesis according to the embodiment of the present invention.

FIG. 6 is an analysis diagram at the time of landing on the tip of the toe of the lower leg prosthesis according to the embodiment of the present invention.

FIG. 7 is a graph showing the relationship between the bending angle of the toe portion and the acting weight load during landing according to the embodiment of the present invention.

FIG. 8 is a graph showing the relationship between the amount of bending deformation of the heel and the weight load that acts upon landing according to the embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Internal skeleton member 2 ... Outer cover member (foot part) 3 ... Outer cover member (lower leg part) 4 ... Lower leg support 5 ... Foot core material 6 ... Hollow core member 7A ... Toe elastic plate 7B ... Heel elastic plate 8 ... Curved foot part 8A ... Lower surface part 9 ... Heel curved plate part 9A ... Lower surface part 10 ... sole plate part 11 ... Foot plate part 12 ... Ankle plate part 13A ... Fixing member 13B ... Fixing member 14A ... Fixing member 14B ... Fixing member 15 ... Column member 16 ... Lower connecting member 17 ... Upper connecting member 18 ... Fixing member 19 ... Notch

Claims (6)

[Claims] 1. A crus prosthesis comprising an internal skeletal member that bears a load, and an outer covering member that surrounds the internal skeletal member in a shape that simulates the foot and the crus. It consists of a rigid lower leg brace and a locally deformable foot core material with rigidity of the foot bone. The foot core material is composed of a curved toe plate part, a curved heel plate part, and lower end parts of both curved plate parts. A highly rigid hollow core member having a sole plate part for connecting the upper and lower curved plate parts, and a foot plate part and an ankle plate part for connecting the upper end parts of both curved plate parts together, and being attached to the sole plate part of the hollow core member. Elastic plate that is deformable in the bending direction of the toe that is extended below the curved toe plate part, and is also attached to the sole plate part and is deformed in the warp direction that is extended below the curved plate part of the heel. A heel elastic plate that is capable of contacting the toe elastic plate. Is fixed to the sole plate portion at a position where the tip end side is formed at a free end portion that can come in contact with and separate from the tip curved plate portion, and the heel elastic plate is on the lower extension of the lower leg support portion of the ankle plate portion. A lower leg prosthesis, which is fixed to the sole plate portion at a position and has a rear end side formed as a free end portion that can come into contact with and separate from the heel curved plate portion. 2. A lower surface portion of the toe curved plate portion and a lower surface portion of the heel curved plate portion are bent in an arc shape, and are warped upward in a direction approaching both the lower surface portions of the toe elastic plate and the heel elastic plate. The lower leg prosthesis according to claim 1, wherein the lower leg artificial leg is formed with a limiting element for limiting the amount of bending to a constant value. 3. The lower leg prosthesis according to claim 1, wherein the elastic plate of the toe and the elastic plate of the heel are formed as a single plate. 4. The distal end free end of the toe elastic plate and the rear free end of the heel elastic plate are in the longitudinal direction of the artificial leg with respect to the distal end portion of the curved toe plate portion and the rear end portion of the curved heel plate portion. The lower leg prosthesis according to claim 1, wherein the lower leg prostheses are located at substantially equal levels. 5. The leg prosthesis according to claim 1, 2, 3 or 4, wherein the internal skeletal member is made of fiber reinforced plastic, and its rigidity and elasticity are adjusted by adjusting the wall thickness or the fiber volume ratio. 6. The leg prosthesis according to claim 5, wherein the reinforcing fibers in the fiber-reinforced plastic forming the toe elastic plate and the heel elastic plate are mainly oriented in the plate longitudinal direction perpendicular to the bending direction.