Blade for prosthetic leg

Abstract

Blade (1) for a prosthetic leg (100), the blade comprising: - a first reinforcing layer (11) of a first material, - a second reinforcing layer (12) of a second material, - a core (13) interposed between the first reinforcing layer (11) and the second reinforcing layer (12), the core being made of a third material different from the first and second materials, characterized in that the blade defines a curvature of which at least one curved portion (U) has a change of direction of more than 120°. Figure for the abbreviation: 1

Description

Title of the invention: Blade for a prosthetic leg

[0001] The invention relates to a blade for a prosthetic leg. The invention also relates to a prosthesis comprising such a blade.

[0002] Leg prostheses comprising a blade connecting an interface to the body of a disabled person to a sole designed to bear weight on the ground and apply forces to the ground during use of the prosthesis are known. These prostheses are intended for participation in sports activities, such as running, trail running, or hiking. The blade used for this type of prosthesis is made entirely of a composite material including carbon fibers. It turns out that such a blade is not optimal because it is expensive, sometimes heavy, and exhibits a very elastic behavior that directly returns energy with very little damping. However, for certain physical activities, a different dynamic behavior of the prosthesis would be desirable.

[0003] The invention aims to provide an alternative prosthesis to this known prosthesis and to overcome the drawbacks mentioned above. In particular, the invention proposes a leg prosthesis that is less expensive, lighter, and has a different dynamic behavior than known prostheses.

[0004] According to the invention, a prosthetic leg blade comprises: - a first layer of reinforcement in a first material, - a second layer of reinforcement in a second material, - a core interposed between the first layer of reinforcement and the second layer of reinforcement, the core being made of a third material different from the first and second materials.

[0005] The blade defines a curvature of which at least one curved portion has a change of direction of more than 120°.

[0006] According to advantageous but not mandatory aspects of the invention, such a blade may incorporate one or more of the following features, taken in any technically permissible combination.

[0007] The third material can be wood or a mix of wood species.

[0008] The third material may be one of the following materials: a foam, cork, a rubber.

[0009] The core can be composed of several layers joined together.

[0010] The core may include one or more openings or recesses.

[0011] Lateral faces of the core can be covered by edges.

[0012] The first material and / or the second material may be a composite material, including a composite material comprising fibers: - of carbon, and / or - aramids, particularly PPD-T (Kevlar®), and / or, - of glass, and / or - linen, bound together by a resin.

[0013] The core thickness can be at least twice the thickness of each of the reinforcing layers.

[0014] The curved portion of the blade may have a radius of curvature at any point greater than five centimeters.

[0015] According to the invention, a prosthetic leg comprises a blade defined above.

[0016] Other features and advantages of the invention will be better understood with the aid of the following description, with reference to the accompanying drawings illustrating, in non-limiting embodiments, how the invention can be implemented, and in which:

[0017] [Fig-1] The [Fig. 1] is a perspective view of a first embodiment of a prosthesis according to the invention.

[0018] [Fig.2] The [Fig.2] is a view of a section along plane AA of the [Fig.1] of a blade of the prosthesis according to the first embodiment.

[0019] [Fig.3] The [Fig.3] is a side view of the prosthesis blade according to the first embodiment.

[0020] [Fig.4] Fig.4 is a perspective view of the core of a blade of a second embodiment of a prosthesis according to the invention.

[0021] [Fig.5] The [Fig.5] is a perspective view of a blade of a third embodiment of a prosthesis according to the invention.

[0022] [Fig.6] The [Fig.6] is a view of a section along plane BB of the [Fig.4] of the blade of the prosthesis according to the third embodiment.

[0023] [Fig.7] The [Fig.7] is a perspective view of a blade of a fourth embodiment of a prosthesis according to the invention.

[0024] [Fig.8] The [Fig.8] is a view of a section along plane CC of the [Fig.6] of the blade of the prosthesis according to the fourth embodiment.

[0025] [Fig.9] The [Fig.9] is a perspective view of a blade of a fifth embodiment of a prosthesis according to the invention.

[0026] [Fig. 10] The [Fig. 10] is a view of a section along plane DD of the [Fig.8] of the blade of the prosthesis according to the fourth embodiment.

[0027] [Fig. 11] The [Fig. 11] is a perspective view of a blade of a sixth embodiment of a prosthesis according to the invention.

[0028] [Fig. 12] The [Fig. 12] is a view of a section along the EE plane of the [Fig. 10] of the blade of the prosthesis according to the sixth embodiment.

[0029] [Fig. 13] The [Fig. 13] is a perspective view of a blade of a seventh embodiment of a prosthesis according to the invention.

[0030] Note that the figures representing the cross-section of the blade are schematic; the different components of the blade (layers, edge) are shown schematically spaced apart from each other, whereas in reality, these components are in contact with each other by means of an appropriate bonding agent such as glue. Furthermore, in the perspective views, the core is represented in a simplified manner when it is multilayered. The individual layers are not shown.

[0031] The invention relates to a prosthetic leg comprising:

[0032] - an interface 2 for attaching the prosthesis to a disabled athlete who has lost a limb or part of a limb, such as a leg or part of a leg, and

[0033] - a sole 3 allowing the disabled athlete to apply force to the ground, and

[0034] - a blade 1 mechanically connecting the interface 2 to the sole 3.

[0035] Interface 2 has a conformation adapted to receive the stump of the disabled person as comfortably as possible while being tight enough to ensure good transmission of forces.

[0036] The sole 3 has, in its lower part in contact with the ground, a structure or relief, for example in the form of cleats, adapted to the nature of the ground on which it will bear. This structure or relief is particularly adapted to limit slippage. To this end, the structure or relief advantageously has a combination of protruding and recessed shapes. The sole can be an added component or a covering applied directly to the blade.

[0037] The blade 1 must exhibit good mechanical behavior to allow for optimal performance of the sporting activity. In particular, it must exhibit:

[0038] - an elasticity characteristic in the direction passing through interface 2 and through The sole 3, meaning that the blade must exhibit elastic return characteristics towards a relative rest position of the interface 2 of the sole 3, particularly when the interface of the sole is brought closer to this rest position. It is this elastic return that provides the energy ensuring good propulsion for the athlete during their movement.

[0039] - a damping characteristic so that, when the athlete leans on the The blade absorbs some of the vibrations from the impact with the ground, reducing the transmission of these vibrations to the thigh. This provides greater comfort for the athlete.

[0040] Prior art blades generally exhibit good elasticity but are often less efficient with regard to damping.

[0041] The invention offers a better compromise between propulsion and damping. Propulsion is provided by the stiffness of the material of the blade's structural element and by the shape of the blade. Damping is provided by the choice of material for the blade's constituent elements and by the shape of the blade.

[0042] To allow for good energy restitution coupled with good damping, the blade, at rest, forms a beam with a curvature, at least one curved portion U of which has a 120° change of direction between the ends of the curved portion. This change of direction of the curved portion U is illustrated in [Fig. 3] by the angle AU. In other words, the average line of the beam forming the blade is generally curved in a sagittal plane P. This average line may locally be straight, for example at the ends of the blade.

[0043] According to a first example, the blade has a "C" shape, the change of direction, represented by the angle AU, is approximately 180° between the ends of the blade, it is therefore possible to identify a curved portion of the "C" curve having a change of direction, represented by the angle AU, of 120° between the ends of the blade.

[0044] According to a second example, the blade has an "S" shape, the change of direction, represented by the angle AU, is approximately 180° between a first end of the blade and a midpoint of the blade and approximately 180° between a second end of the blade and the midpoint of the blade, it is therefore possible to identify several curved portions of the "S" curve exhibiting a change of direction of 120° between the ends of the blade.

[0045] When manufacturing a prosthetic blade, the manufacturer faces the challenge of shaping the blade within dimensional limits in height without compromising its mechanical properties. Indeed, the height of the blade must be compatible with the height of the amputated limb. When the blade has a simple mean line, such as a straight line, or a change of direction of less than 120°, curving the blade presents no significant difficulty. If the change of direction exceeds 120°, the shaping operation becomes more delicate. It is therefore desirable to avoid excessive variation in the blade's curvature to prevent damage during shaping. Thus, the radius of curvature R in the curved portion U is advantageously always greater than five centimeters.As we will see later, shaping can also be facilitated by using a structure comprising several layers of reduced thickness rather than a structure comprising one or more thick layers.

[0046] When the blade is under stress, this specific blade shape allows, on the one hand, good elastic deformation of the blade, thus contributing to damping during a reception / support phase, and, on the other hand, very good energy restitution of this, during a propulsion phase. This energy return creates a spring effect that energizes the stride.

[0047] The invention lies particularly in the specific structure of the blade. This comprises: - a first reinforcement layer 11 in a first material, - a second reinforcement layer 12 in a second material, - a core 13 interposed between the first reinforcement layer 11 and the second reinforcement layer 12, the core being made of a third material different from the first and second materials.

[0048] This specific construction makes the prosthesis lighter and therefore provides greater comfort for the user. Furthermore, this structure improves its damping properties, primarily due to the composition of the core. Indeed, the weight of the blade and its damping properties can be adjusted by appropriately selecting the core material.

[0049] The reinforcing layers 11 and 12 and their relative positioning make it possible to obtain the necessary rigidity and elasticity characteristics of the blade 1. To obtain such rigidity and elasticity, it is important that the reinforcing layers be kept at a distance from each other. This separation is advantageously achieved by the presence of the core 13, interposed between these layers. The first reinforcing layer 11 defines a first (external) surface of the blade (i.e., a first surface exposed to the environment outside the blade). The second reinforcing layer 12 defines a second (external) surface of the blade (i.e., a second surface exposed to the environment outside the blade).

[0050] In the embodiments described in Figures 1 to 13, the first reinforcing layer 11 is oriented towards the inside of the blade's curvature, on the concave side of the blade, and the second reinforcing layer 12 is oriented towards the outside of the blade's curvature, on the convex side of the blade. In these examples, the interface 2 and the flange 3 are fixed against the second reinforcing layer 12, as seen in [Fig. 1].

[0051] The first reinforcing layer 11 can be made of a composite material, in particular a composite material comprising: - carbon fibers, and / or - aramids, particularly PPD-T (Kevlar®), and / or, - basalt, and / or - glass, and / or - flax, bonded together with resin to form a ply. The first reinforcing layer 11 may comprise one or more plies. Within each ply, the fibers may be arranged in a weave or mat, or arranged parallel to each other. in a single direction. The fiber orientation of a ply can advantageously be different from the fiber orientation of adjacent plies of the first reinforcing layer.

[0052] The second reinforcing layer 12 can be made of a composite material, in particular a composite material comprising: - carbon fibers, and / or - aramids, particularly PPD-T (Kevlar®), and / or, - of basalt, and / or - of glass, and / or -linen, bonded together with resin to form a fold. The first reinforcing layer 11 may comprise one or more plies. In each plie, the fibers may be arranged in a weave or mat, or arranged parallel to each other in a single direction. The fiber orientation of a plie may advantageously differ from the fiber orientation of adjacent plies in the first reinforcing layer.

[0053] The number of plies and the orientation of the fibers between adjacent plies of these reinforcing layers 11, 12 allow adjustment of the blade's stiffness and therefore its dynamic properties, propulsion and damping. The blade can thus be dimensioned to achieve optimal dynamic behavior according to the weight and the desired use.

[0054] According to one embodiment, the first and second reinforcement layers 11 and 12 are made of the same material, but not necessarily.

[0055] The first reinforcement layer 11 and / or the second reinforcement layer 12 may have a straight cross-section geometry, in particular a thickness, that varies along the blade 1 (depending on the curved length of the blade 1). In other words, for this embodiment, the thickness of one or both reinforcement layers is variable. For example, the variation in the thickness of a reinforcement layer may result from a variation in the number of plies locally, depending on the cross-sections.

[0056] The blade 1 comprises a core 13 in the form of a curved plate whose two largest surfaces are covered by the reinforcing layers 11 and 12. In other words, the core 13 is intercalated between the two reinforcing layers 11 and 12.

[0057] In order to combine the elasticity and damping characteristics of the blade 1, the material constituting the core 13 is different from the material constituting the reinforcement layers 11, 12. The material of the reinforcement layers 11, 12 contributes mainly to the elasticity and the material constituting the core 13 contributes mainly to the damping.

[0058] The core is therefore made of a material with good damping characteristics.

[0059] According to one embodiment, the core is made of wood or a mixture of wood species. In particular, the core may be made of one or more plies of one or more wood species. Wood species providing a good compromise include one or more of the following: maple, especially Canadian maple, poplar, beech, karuba, paulownia, ash, and bamboo.

[0060] The use of a wooden core provides good damping and allows for a lighter blade structure. Furthermore, wood is a relatively economical and ecological material.

[0061] Alternatively, the core can be made with one of the following materials: - a foam, such as polyurethane foam, polypropylene foam, airex®, rohacell® (polymethacrylic foam), - cork, - rubber.

[0062] These materials turn out to be rather lightweight.

[0063] To further lighten the blade, the core may include one or more openings or recesses 131 as shown in [Fig. 4]. The recesses 131 may have a cross-sectional geometry that evolves along the blade 1 (depending on the curved length of the blade 1).

[0064] According to one embodiment, the core 13 forms a single layer, of thickness E13, made of a single material, as shown in the embodiments of Figures 1 to 6. This construction simplifies the manufacture of the blade. However, its curved shape becomes more difficult as the core is thicker. Furthermore, the thickness induces greater rigidity.

[0065] According to other embodiments, the core 13 consists of several layers of the same material or of different materials, as seen in the embodiments of figures 7 to 12. The materials may be different in that they have different natures and / or have different physicochemical characteristics.

[0066] In the embodiments of figures 7 to 10, the core consists of a stack of three layers 137, 138, 139 made of the same material, for example, the same type of wood.

[0067] In the embodiment shown in Figures 11 to 12, the core consists of a stack of three layers 137b, 138b, 139b made of different materials. For example, each of layers 137b and 139b may be a layer of wood or a stack of wood layers, and layer 138b, sandwiched between layers 137b and 139b, may be a composite reinforcement layer based on carbon fibers and resin. In another variant, the core may comprise several composite reinforcement layers, such as layer 138b, sandwiched between wood layers, such as layers 137b and 139b.

[0068] According to one variant, the reinforcing layer 138b may be local and not extend along the entire length of the blade. For example, it may be present only at the ends and not at the curvature of the blade, as seen in [Fig. 13].

[0069] According to another example, the core layers constitute a mix of layers having different wood species, i.e. a laminated structure whose plies are made of wood of different species.

[0070] Alternatively, the layers can be formed from the same material arranged differently in each layer. The layers can thus be identified and delimited even though the material is the same. For example, layers 137, 138, and 139 can be three layers (or plies) whose fibers are oriented differently from one another with respect to a reference plane. For example, the fibers of layer 138 can be oriented parallel to plane P. The fibers of layer 137 can be oriented at an angle of 45° to the reference plane. The fibers of layer 139 can be oriented at an angle of -45° to the reference plane. These fiber orientations between the constituent layers make it possible to adapt the mechanical behavior of the blade according to the desired performance.

[0071] The fibers can be wood fibers, another natural material or a filler of a plastic material.

[0072] The core 13 may have a cross-sectional geometry, in particular a thickness, that varies along the blade 1 (according to the curved length of the blade 1). In other words, for this embodiment, the core thickness is variable. For example, the variation in the core thickness may result from a variation in the number of layers locally, depending on the cross-sections.

[0073] When the core is multilayered. The layers are bonded together by any suitable means such as gluing or heat fusion. For example, to assemble layers of wood, epoxy resin or wood glue can be used.

[0074] According to one embodiment, the thickness E13 of the core 13 is at least twice greater than the thickness Eli, E12 of each of the reinforcement layers 11 or 12. This makes it possible to lighten the blade, by choosing a core material less dense than the reinforcement layers, and to obtain good behavior of the blade for both propulsion and damping.

[0075] According to another embodiment, as illustrated in Figures 5, 6, 9, and 10, the blade 1 comprises edges 14, 114, 124 covering lateral faces 135 of the core 13. By "edge," we mean elements covering the lateral faces 135 of the core 13. The presence of these edges 14, 114, 124 allows the core 13 to be encapsulated between the edges 14, 114, 124 and the reinforcing layers 11 and 12. The core 13 is thus isolated from the outside and therefore protected from external environmental aggressions, primarily to protect it from mechanical aggressions (pebbles, sand, etc.) and from physicochemical aggressions (water, cold, heat, etc.). This therefore allows for a wider choice of materials for making the core. This allows us to choose a high-performance material for damping without it necessarily being resistant to external stresses, which would not be possible if the core were exposed.These edges can be made from a suitable material that is resistant to weathering and other external stresses. For example, they can be made of plastic.

[0076] In addition to protecting the core, the edges allow for greater freedom in the aesthetic design of the blade 1. Indeed, the edges can present multiple combinations of lines and colors to produce an aesthetic effect.

[0077] A side panel can be an added piece, distinct from the reinforcing layers, as seen with the embodiment of figures 5 and 6.

[0078] Alternatively, an edge can be formed by one or both of the reinforcing layers 11 or 12. In this case, one or both of the reinforcing layers 11, 12, extends laterally on each side by a substantially vertical extension. Figures 9 and 10 illustrate an embodiment where the edge is formed by an extension 124 of the reinforcing layer 12.

[0079] The first reinforcing layer 11 is attached to the core 13 by any suitable means, for example, glue. The second reinforcing layer 12 is attached to the core 13 by any suitable means, for example, glue.

[0080] The bonding can be carried out using epoxy glue or polyester glue.

[0081] According to an advantageous embodiment, the different layers 11, 12, 13, 137, 138, 139, 137b, 138b, 139b intended to constitute blade 1 are glued and placed in a shaping system where blade shaping constraints are applied to deform and maintain the different deformed layers throughout the entire drying time of the glue. After drying, the blade can be removed from the shaping system.

[0082] The solution of a blade with a core 13 comprising several layers 137, 138, 139, 137b, 138b, 139b proves particularly relevant for this process because it is much easier to bend thin layers than a core composed of a single thicker layer, especially when a curvature is desired in which at least one curved portion U has a change of direction of more than 120°.

[0083] In a preferred embodiment: - Core 13 is composed of five layers of wood, and - the reinforcement layers 11,12 are composed of seven plies made of carbon fibers and resin.

[0084] The invention is not limited to the embodiments described above. It is also possible to combine these embodiments. The invention extends to all embodiments covered by the appended claims. References

[0085] 100. Leg prosthesis

[0086] 1. Blade 11. First layer of reinforcement 114. Vertical extension / edge 12. Second layer of reinforcement 124. Vertical extension / edge 13. Core 131. Update / Obviousness 135. Side view 137. Layer 138. Layer 139. Layer 14. Song

[0087] 2. Interface

[0088] 3. Sole

Claims

Demands

1. Blade (1) for prosthetic leg (100), the blade comprising: - a first reinforcement layer (11) of a first material, - a second reinforcement layer (12) of a second material, - a core (13) interposed between the first reinforcement layer (11) and the second reinforcement layer (12), the core being made of a third material different from the first and second materials, characterized in that the blade defines a curvature of which at least one curved portion (U) has a change of direction (AU) of more than 120°.

2. Blade (1) for prosthetic leg (100) according to claim 1, characterized in that the third material is wood or a mix of wood species.

3. Blade (1) for prosthetic leg (100) according to claim 1, characterized in that the third material is one of the following materials: a foam, cork, a rubber.

4. Blade (1) for prosthesis (100) of leg according to any one of the preceding claims, characterized in that the core is composed of several layers (137, 138, 139) joined together.

5. Blade (1) for prosthetic leg (100) according to any one of the preceding claims, characterized in that the core (13) comprises one or more openings or recesses (131).

6. Blade (1) for prosthesis (100) of leg according to any one of the preceding claims, characterized in that lateral faces (135) of the core (13) are covered by edges (14, 114, 124).

7. Blade (1) for prosthesis (100) of leg according to any one of the preceding claims, characterized in that the first material and / or the second material is a composite material, in particular a composite material comprising fibers of: - carbon, and / or - aramids, in particular PPD-T (Kevlar ®), and / or, - basalt, and / or - glass, and / or - flax, bonded together by a resin.

8. Blade (1) for prosthetic leg (100) according to any one of the preceding claims, characterized in that the thickness (E13) the core (13) is at least twice the thickness (Eli, E12) of each of the reinforcing layers (11, 12).

9. Blade (1) for prosthetic leg (100) according to any one of the preceding claims, characterized in that the portion (U) of the blade (1) has a radius of curvature (R) at any point greater than five centimeters.

10. Leg prosthesis (100) comprising a blade (1) according to any one of the preceding claims.

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