FR3086860A1 - PROSTHETIC FOOT - Google Patents

Abstract

Prosthetic foot (1) comprising a lower support part (la) having a lower face (F1) defining a bearing surface of the prosthetic foot on the ground and an upper face (F2), the prosthetic foot (1) also comprising a connection extension (lb) extending from the lower support part (la) to form a mechanical connection between this lower support part (la) and a member of a subject, this connection extension (lb) having a front face (F3) and a rear face (F4) which extend on either side of the connection extension (lb), the prosthetic foot (1) having a closed contour (C) extending along the front (F3), upper (F2), lower (F1), and rear (F4) faces. This foot 1 comprises at least a first wire (31) extending along the closed contour (C) and around a zone of material of the prosthetic foot which forms a core (N).

Description

BACKGROUND OF THE INVENTION

It is known, for example from patent document US8366789, a prosthetic foot comprising a lower support part having a lower face and an upper face which extend on either side of the

part lower, the lower side defining a area support foot prosthetic on 1 e soil. This foot protr letic includes also a

connection extension extending from the lower support part to form a mechanical connection between this lower support part and a member of a subject.

This connection extension has a front face and a rear face which extend on either side of the connection extension, this prosthetic foot having, in a sagital plane, a closed contour extending along the face front, top side, bottom side, and back side. This closed contour is for example visible in a section along a sagital plane (vertical) of the prosthetic foot while its underside is resting on the ground.

Prosthetic feet need sufficient mechanical strength to allow a given subject to move without fear of rupture of the prosthetic foot.

It is also desirable that the prosthetic foot has a size and a shape adapted to the need of the subject.

To this end, the manufacturers of prosthetic feet generally distribute ranges of prosthetic feet declined in several sizes / sizes and in several types of mechanical structures.

Each mechanical structure is adapted to:

- a weight girl of subjects to be fitted; and eventually

- a particular need for energy restitution during walking or running.

Thus, to allow the selection of a prosthetic foot adapted to the size and weight of the subject, the ranges of prosthetic feet must be declined in several sizes and possibly in several types of mechanical structures.

The financial and technical investment increases with the size of the range which can push some manufacturers to decline only a few models of prosthetic feet for the sizes of the least diffused feet.

There is therefore a need to improve the customization of prosthetic feet to the needs of the subject to be fitted without having to increase the volume of prosthetic foot stocks.

OBJECT OF THE INVENTION

In order to solve at least some of the above problems, an object of the present invention is to provide a prosthetic foot and a method of manufacturing such a prosthetic foot.

SUMMARY OF THE INVENTION

To this end, a prosthetic foot is proposed according to the invention comprising a lower support part having a lower face and an upper face which extend on either side of the lower part. The underside defines a bearing surface of the prosthetic foot on the ground.

The prosthetic foot also has a connection extension extending from the lower support part to form a mechanical connection between this lower support part and a member of a support.

This connection extension has a front face and a rear face which extend on either side of the connection extension.

The prosthetic foot has a closed contour extending along the front face, the upper face, the lower face, and the rear face.

The prosthetic foot according to the invention is essentially characterized in that it comprises at least one first wire extending along the closed contour and around an area of material of the prosthetic foot which forms a core, that is to say - say a fill.

For the understanding of the invention, the term closed contour designates a continuous line closed on itself and situated at the intersection between a section plane and each of the front, upper, lower and rear faces of the prosthetic foot.

For example, a closed contour of the prosthetic foot is a continuous closed contour observable in a vertical section plane of the prosthetic foot passing through its lower part and through its connection extension, this plane cutting each of the front, upper, lower and rear faces of the prosthetic foot.

Having at least one first wire extending along the closed outline (i.e. extending along the front, back, bottom and top sides of the prosthetic foot) while being around a zone of material of the prosthetic foot which forms a core makes it possible to increase the mechanical resistance of the prosthetic foot.

During walking, the structure of the prosthetic foot works mainly in flexion with a dynamic evolution of internal stresses in the prosthetic foot.

The further one moves away from a neutral line of current flexion, the more the mechanical stresses in the prosthetic foot increase.

Thus, the maximum mechanical stresses are found along the

As the said at least one first wire extends along the outline, it always has one to take up the

This avoids the appearance of cracking zones

since the first thread there opposite. In other term s, during walking, This thread allows ; of resume constraints maximum in the foot prosthetics and the resistance mechanical foot

prosthetic is improved.

Furthermore, as the first wire extends between different areas of the prosthetic foot, it allows forces to be distributed between areas of the prosthetic foot through which it passes.

As will be seen later, the prosthetic foot according to the invention preferably has several wires distributed in different layers which are parallel to one another and plane.

Each of these wires extends along this same closed contour and thus confers the same advantages as those conferred by said first wire.

We can thus choose the number of these wires, the number of layers and mechanical characteristics of each of these wires to adapt the prosthetic foot to the size and weight of the subject as well as to his way of moving.

The mechanical characteristics of each of these wires and their arrangements define the ability of the foot to deform as well as its different stiffnesses and elastic limits.

According to another aspect, the invention also relates to a method of manufacturing a prosthetic foot according to any one of the embodiments of prosthetic foot according to the invention.

This manufacturing process according to the invention is essentially characterized by the formation of successive layers generating said core and said at least one first closed contour being deposited successively.

Each of the layers depositing at least one material at least one neighboring layer in that it comprises the lives allowing at least of closed contour, and in that wire which extends along between two of these successive layers is formed by i and it is supported against the succession of layers with which it is secured.

The fact of placing said at least one first wire between two of the successive layers makes it possible on the one hand to position each wire exactly at the desired location in the volume of the prosthetic foot while improving the mechanical cohesion between each given wire and the constituent materials of these layers. It should be noted that the wire extends in a layer placed between two neighboring layers.

We thus manage to produce a prosthetic foot conforming to a virtual mechanical model predefined in three dimensions.

The prosthetic foot thus obtained conforms in terms of dimensions and mechanical strength compared to the predefined virtual model.

This process also allows the prosthetic foot to be personalized to the needs of the subject.

We can for example generate a virtual prosthetic foot model adapted to the characteristics of the subject to be fitted and a mechanical strength objective of the prosthetic foot to be achieved.

Then, on the basis of this virtual model, the prosthetic foot is created by forming successive layers on top of each other and by intercalating wires between two successive layers. These threads are used to increase the mechanical resistance of the prosthetic foot. According to the invention, at least one of these wires extends along the closed contour which is along each of said lower, upper, front and rear faces of the prosthetic foot.

A prosthetic foot having the above characteristics is thus generated on demand.

During the formation of successive layers, it is also possible to deposit reinforcing threads against some of these successive layers so that each of the reinforcing threads thus deposited is caught between two of these successive layers which are adjacent to it and against which it is in contact, at least some of these reinforcing wires also being taken inside the core of the prosthetic foot thus formed.

Each of the successive layers can also extend in a plane which is specific to it and which is perpendicular to more or less 20 ° of angle close to a stable support plane of the prosthetic foot defined by points of the underside of the prosthetic foot, these successive layers being parallel to each other.

BRIEF DESCRIPTION OF THE DRAWINGS

Other characteristics and advantages of the invention will emerge clearly from the description given below, by way of indication and in no way limitative, with reference to the appended drawings, in which:

- Figures 1 to 3 show sectional views of a prosthetic foot according to the invention in longitudinal planes parallel to each other, it can be seen in these figures that the arrangement of the wires and the shape of the core evolves by changing the plane of section to obtain a wire structure and a three-dimensional core specifically adapted to the subject's needs;

- Figure 4 shows a perspective view of the prosthetic foot according to the invention.

DETAILED DESCRIPTION OF THE INVENTION

As indicated previously, the invention relates to a prosthetic foot 1 illustrated by FIGS. 1 to 4. Although each of Figures 1 to 3 shows a section of the same prosthetic foot, these same views in section

could illustrate different modes of realisation of prosthetic feet. The objective of these cuts is of demonstrate that thanks to the invention, we can get a wide variety

internal structures of prosthetic feet, each internal structure comprising a core N of desired shape, this core being surrounded by wires extending at the periphery of the foot. The nucleus may be a solid structure or, on the contrary, it may have voids which may be empty cells with rigid walls. As will be seen hereinafter, the shape of these cells can vary and we can for example have a nucleus whose cells are structured to form a honeycomb.

Each particular structure is formed of successive layers between which these wires are placed.

The prosthetic foot is thus particularly suited to the needs of the subject to be fitted.

In more detail, the prosthetic foot 1 according to the invention comprises a lower support part presenting it with a lower face F1 and an upper face F2, these faces F1, F2 extending on either side of the lower part the.

The lower face F1 defines a bearing surface of the prosthetic foot 1 on the ground.

The support surface of the prosthetic foot comprises at least three support points PI, P2, P3 distant from each other which together define a stable support plane P of the prosthetic foot when the prosthetic foot is placed on a flat floor with its lower face Fl resting on this plane ground P.

Preferably, the lower face F1 has first and second surfaces respectively rounded according to respective first and second arcs.

The first of these arches extends from a front edge of the prosthetic foot to a middle region of the lower face F1.

The second of these arches extends from this middle zone to a rear edge of the prosthetic foot.

These first and second arcs are curved in the direction of the ground to allow a progressive displacement of the points of contact of the lower face F1 with the ground.

This limits shocks during walking.

The prosthetic foot 1 also includes a connection extension 1b extending from the lower support part la to form a mechanical connection between this lower support part la and a lower member of a subject to be fitted.

This connection extension 1b has a front face F3 and a rear face F 4 which extend on either side

else d © The extension connection 1b. IjcL front face F3 is dest innate to be ori entry in the direction of movement of subject * and while the face back F4 is destir linked to be oriented in the meaning reverse of walking. The extension of connection 1b presents a portion

of upper surface lb2 substantially parallel to the lower face F1 of the lower part la.

This upper surface portion lb2 is arranged to support the support of an apparatus of a limb of a subject and thus serve as a mechanical connection zone for connecting the prosthetic foot 1 to the limb of the subject.

The connection extension has an end portion IblO which extends from the upper surface portion lb2 while approaching the upper face F2 of the lower part la.

This terminal portion IblO of the connection extension 1b has a terminal end Ibl which is located opposite the upper face F2 of the lower part 1 while being at a distance from this upper face F2.

This terminal end Ibl is adapted to abut against the upper face F2 to limit a bending amplitude of the prosthetic foot around axes parallel to a main bending direction D.

The terminal end ibl is adapted to abut against the upper face F2 at a point Pt of this upper face F2 which is located at a distance from a front end lalO of the prosthetic foot between 25% and 50% of a length total of the prosthetic foot measured between a rear end la20 of the prosthetic foot and said front end lalO.

The position of this upper F2 towards the front of the and 50% of its length, makes it possible to limit the amplitude of the pressing force against the limited.

Positioning the front of the foot, more use in a shoe.

Upper perforations lb2 allow point Pt against the prosthetic foot face, between 25% to have a large bending torque while having an upper face F2 which remains from this support point Pt, at 25% of its length, allows its lb3a, lb3b of the surface fixing said limb apparatus.

These perforations lb3a, lb3b pass entirely through the connection extension 1b and each have a counterbore oriented towards the upper face F2 to receive an insert or a screwing head.

It is also conceivable that these perforations lb3a, lb3b are defined by one or more inserts.

By convention, the rear face F4 covers this connection area and the front face F3 extends from the connection area which forms a limit from the rear face F4 to the upper face F2.

Preferably, the connection extension 1b has a radius of curvature which is reduced by moving away from the upper face F2 and going towards one of the perforations lb3b. This allows to have a progressive and continuous evolution of the constraints

mechanical along this connection extension 1b up to the liai area his. As illustrated in the figure 4, extension of connection 1b forms a spring to blade suitable for is de f o rme r mainly t in flexi we around axes of bending D 'parallels between them and parallel to; donkey direction bending privileged D when a charge axial is applied ai at level of the connection area in

direction of the lower part of the prosthetic foot.

The prosthetic foot 1 has a closed contour C extending along the front face F3, the upper face F2, the lower face F1, and the rear face F4.

This closed contour C can be observed in each cutting plane which passes simultaneously through the front face F3, the upper face F2, the lower face Fl, and the rear face F4.

As can be understood from FIGS. 1 to 4, the closed contour C is an external limit of the prosthetic oied which passes successively through the front face F3, then through a front portion of the upper face F2, then through the lower face F1, then through a rear portion of the upper face F2, then via the rear face F4 (where the connection zone is located) to return to the front face F3. The prosthetic foot 1 according to the invention comprises at least a first wire 31 extending over its entire length along the closed contour C, that is to say along each of the faces F1, F2, F3, F4 while being away from this closed contour C.

This at least one first wire 31 also extends all around a zone of material of the prosthetic foot which forms a core N. Thus, the prosthetic foot according to the invention is a monolithic part on which an apparatus forming a interface between the prosthetic foot and the subject's leg.

When pressure is exerted on the connection extension 1b in the direction of the lower face F1, under the effect of bending, certain zones of the prosthetic foot are then stressed in traction.

Portions of the first wire which are in these areas subjected to tensile stress then take up part of these efforts and limit the risk of occurrence

cracking. The charac : teristical ! S stiffness elastic thread infl ' uent on ability of deformation elastic of the foot. So when ? the : market from subject, this first r wire 31 allows to resume a part at less of oriented constraints along the closed outline ς Like this same wire 31 tightens everything around core

N, it also promotes the mechanical cohesion of the prosthetic foot around its nucleus N.

To maximize the mechanical reinforcement effect, each portion of the first wire 31 is at a distance from the closed contour C, this non-zero distance being strictly less than 10 mm and preferably less than 5 mm.

Preferably, said first wire 31 comprises several long fibers, that is to say fibers of several centimeters along. Preferably, these fibers of the first wire extend over the entire length of the first wire.

The use of long fibers which extend in length along the closed contour C makes it possible to increase the mechanical resistance of the protein foot 1 while limiting the risk of breaking the first wire 31.

Preferably, the first wire 31 is arranged to form in at least one first plane Psi perpendicular to more or less 20 ° of angle close to the stable support plane P, at least one first line L1 curved on itself and extending over its entire length along the closed contour C.

Over its entire length, said at least one first curved line L1 extends at a distance from said closed contour C.

Preferably, this at least one first curved line L1 extends along at least 90% of a total length of the closed contour C. In one embodiment, it can be envisaged that said first line L1 curved on it- same which extends in the foreground Psi forms there several turns Bl, B2, B3, B4 preferentially concentric with respect to each other.

By producing several coplanar turns using the same wire 31, the capacity for taking up tensile forces along the closed contour is greatly increased.

According to an embodiment possibly complementary to the previous one, it can be envisaged that the prosthetic foot comprises at least one second wire 32 distinct from the first wire 31, this second wire 32 comprising several fibers.

As illustrated in FIG. 1, this second wire 32 can be used to form in said first plane Psi, at least one second line L2 curved on itself and extending on the one hand along said closed contour C and on the other hand around the area of material of the prosthetic foot which forms a core N.

This second wire 32 makes it possible to reinforce the effects of mechanical resistance provided by the first wire 31.

Preferably, the fibers that make up the second thread 32 are also long fibers.

Ideally, the first and second lines LI, L2 formed with the first and second wires 31, 32 are spaced from one another in the entirety of said first plane Psi.

This makes it possible to have a zone of continuous material between these lines LI, L2 to connect together parts of the prosthetic foot located on either side of the foreground Psi.

your cohesive jn of prosthetic foot between layers parallel to each other is so reinforced. Always for to reinforce the cohesi we enter separate layers ; s of foot it East too possible to make sure that the first fi 1 31 form in at least a second plan Ps2 separate from the first Psi plan and perpendicular to more or less 20 ° angl e close opposite

screw of the stable support plane P, at least one second line curved on itself and extending along the closed contour C.

In other words, the first wire can be used to produce on the one hand the first line L1 wound around the core of material in the first plane Psi and on the other hand the second line wound around the new material N in the second plan Ps2.

According to this embodiment, the same first wire is used, without discontinuity, to produce flat curved lines in planes substantially parallel to one another (at more or less 20 ° angle).

Each of these lines is formed around the same core N which it surrounds and along and inside the closed contour C. These two flat curved lines are connected together by at least a portion of the first wire which s extends between the Psi planes, Ps2 containing these curved lines.

Alternatively to this mode where the first wire forms loops in several Psi, Ps2 planes, it is possible that

Preferably, the first wire 31 extends exclusively (only) in the first plane Psi, the terminal ends T1, T2 of this first wire 31 being in this first plane Psi. In this case, said first curved line L1 formed in this first plane Psi forms at least one turn and overlapping portions of this first wire.

By convention, the ends of the wires which follow the closed contour are represented by points of diameters greater than the wire. Of course each end of a given wire is of the same diameter as this wire.

Preferably, the terminal ends T1, T2 of said first wire 31 are located in the terminal portion IblO and they are spaced from each other by at most 1 centimeter.

By limiting the spacing between the ends of the first wire to at most 1 centimeter, a solution is provided to avoid overlapping of this first wire on itself while limiting the risk of incipient breakage at the ends of this first wire.

Preferably, in each of the embodiments of the invention, the ends of the wires (for example the ends of the first and second wires) are made raw which form curved lines which extend along the closed contour and around the core of matter are:

- closer to the front face F3 than to the rear face F4; and

- closer to the upper face F2 than to the lower face Fl.

These end ends of the wires are thus located in areas of the prosthetic foot which undergo the least mechanical stress during normal walking.

Preferably as illustrated in the figure

2, the connection extension has at least a third wire 33 disposed exclusively between two of said perforations lb3a, lb3b and forming a closed loop in a plane of longitudinal section of these two perforations lb3a, lb3b.

This third wire 33 locally strengthens the connection zone with the subject's apparatus.

The number of wires extending along the closed contour C in one or more planes is variable depending on the mechanical characteristics of the foot that one wishes to obtain.

as seen in FIGS. 1 and 2, the prosthesis can also include several reinforcing wires 40 which extend in one or more of said planes Psi, Ps2, Ps3 perpendicular to more or less 20 ° angle near vis- with respect to a stable support plane P.

These reinforcing wires 40 are arranged in zigzags with curved portions for changing direction and straight portions connected together by these curved portions. The straight portions of each given reinforcing wire forming these zigzags are preferably parallel to one another.

Preferably, the straight portions of a given reinforcing wire are oriented in a direction of maximum bending to which this reinforcing wire must

to oppose. The directions of portions straight lines ; son frame 4 0 therefore vary from a thread to the other in funct ion of the d irection the bending force maximum dan s the area concerned. Ceri tains at least these reinforcing wires a 40 are also taken inside .eur of the nucleus N foot prosthetic • The son frame 4 0 are sons fiber long who t intended to arm zones foot prosthetic as its core N and who do not follow the contour C. We can predict that prosthetic foot behaves many kinds sons 31, 32, 33, 40 which differ

of each other in terms of materials or in terms of sections of the fibers constituting these threads or in terms of arrangements of the fibers in these threads.

Thus, the fibers of the reinforcing wire 40 may differ from the fibers of the first wire 41 in terms of material and / or average fiber diameter and / or average fiber length and / or arrangement of the fibers in the wire.

Typically each thread of the prosthetic foot consists of fibers chosen from the group of fibers comprising glass fibers, carbon fibers, kevlar fibers.

To manufacture a prosthetic foot according to the invention, using an additive manufacturing tool, a plurality of successive layers is formed.

These successive layers are parallels Between them and perpendicular to plus or less 20 ⁰ of angle close to a support plane stable P of foot prosthetic. This generates said core NOT and said

closed contour C.

These layers are preferably made of the same material and they have the same thickness.

Using a wire deposition tool and during the formation of the plurality of successive layers, each of said wires is deposited so that each given wire is in at least one plane extending between two of the successive layers which match him.

The wires 31, 32, 40 are preferably deposited using a head or several movable heads moved by actuators of an automaton / robot executing a manufacturing program established according to a virtual model of foot to be manufactured .

Each movable head is supplied with wire (s) from a stock of wire (s) connected to the head.

It is also conceivable that the same head used for depositing wire (s) is also equipped with one or more material distribution nozzles for the creation of successive layers, the same head thus performing the two deposition operations. yarn and diaper manufacturing.

The material distributed to manufacture a layer is for example a curable resin such as a thermoplastic resin. This material can be in the form of a wire of material to be melted or particles of material to be melted and to be distributed via an extrusion nozzle.

Each layer may have hollow areas which

which allows lighten the foot and for example these layers can be honeycomb like r £ ^ presented on the figure 3. The direction of manufacturing of layers matches at direction D. We could also face that the or 1 are sons

31, 32, 33, 40 are preformed according to one or more predetermined standard arrangements and that after having formed a given layer, this or these preformed wires is positioned directly on this given layer before forming the next layer.

Thus, the tool for depositing the wire could be a simple arm for gripping preformed wire.

It is also conceivable that the deposition of the wire takes place under conditions favoring its adhesion to the layer which supports it. For example, this wire could be deposited on a layer still in fusion or covered with an adhesive.

Alternatively, it is conceivable that the deposition of a new layer on a wire already positioned on a previously formed layer is produced so as to trap this wire between these two layers while welding / bonding it to each of these two layers.

Although the sectional views of Figures 1, 2 and 3

present three arrangements different from son 31, 32, 33, 40, in three plans Dec : different oupes and parallels between them, he is too possible that sons be arranged in a way uniform in each

of these cutting plans.

Claims (18)

1. Prosthetic foot (1) compre part lower d support feeling a lower face earlier (Fl) and a upper side (F2) which extend from go and other Of the game lower (la), r a face lower (1 II) defining a surface support foot prosthetic On the ground, foot prosthetic (D comprising é ^ cheerfully an extension of connection (1b) extending from the part lower d Eappui (la) for form a mechanical connection between this P art ie lower d ¹ '' support a member of 'a subject, this extension of connection (1b) presenting a face before (F3) and a rear side (F4) which has been share on and else of the extension of connection (1b), the foot prosthetic (1) presenting a cont our closed (VS) extending along the front face (F3), the upper face (F2), the lower face (Fl), and the rear face (F4), characterized in that it comprises at least one first wire (31) extending along the closed contour (C) and around an area of material of the prosthetic foot which forms a core (N). 2. prosthetic foot (1) according to claim 1, wherein said first wire (31) comprises several fibers which extend over the entire length of this first wire (31). 3. prosthetic foot according to any one of claims 1 or 2, wherein said support surface of the prosthetic foot comprises at least three support points (PI, P2, P3) distant from each other which together define a plane stable support (P) of the prosthetic foot when the prosthetic foot is placed on a flat floor with its underside (Fl) resting on this flat floor (P), the first wire (31) forming in at least one first plane (Psi) perpendicular to plus or minus 20 ° of angle close to the stable support plane (P), at least one first line (Ll) curved on itself and extending over its entire length along the closed contour (C). 4. Prosthetic leg according to claim 3, wherein said at least one first curved line (L1) extends over its entire length along the closed contour (C) while being at a distance from this closed contour (C). 5. Prosthetic leg according to claim 4, wherein said at least one first curved line (L1) extends along at least 90% of a total length of the closed contour (C). 6. prosthetic foot according to any one of claims 3 to 5, wherein said first line (L1) curved on itself which extends in the foreground (Psi) forms several turns (Bl, B2, B3, B4 ) in this foreground (Psi). 7. Prosthetic foot according to any one of claims 3 to 6, comprising at least one second wire (32) distinct from the first wire, this second wire comprising several fibers, this second wire (32) forming in said first plane (Psi) , at least a second line (L2) curved on itself and extending along said closed contour (C) and around the area of material of the prosthetic foot which forms a core (N), the first and second lines ( L1, L2) being spaced from each other in the entirety of said foreground (Psi). 8. Prosthetic leg according to any one of claims 3 to 7, wherein the first wire (31) forms in at least one second plane (Ps2) distinct from the first plane (Psi) and perpendicular to more or less 20 ° d ' near angle with respect to the stable support plane (P), at least one second line curved on itself and extending along the closed contour (C). 9. Foot according to claim 3, in which the first wire extends exclusively in the first plane, the terminal ends (T1, T2) of this first wire (31) being in this first plane and said first curved line formed in this first plane forming at least one turn with portions of this first wire which overlap. 10. Foot according to claim 9, wherein the terminal ends (T1, T2) of said first wire are spaced from each other by at most 1 centimeter. 11. Prosthetic leg according to any one of claims 9 or 10, wherein the connection extension (1b) has an upper surface portion (lb2) substantially parallel to the lower face (Fl) of the lower part (la) , this upper surface portion (lb2) being arranged to support the support of an apparatus of a limb of a subject and thus serve as a connection zone for connecting the prosthetic foot (1) to the limb of the subject, the extension connection having a terminal portion (IblO) which extends from the upper surface portion (lb2) by approaching the upper face (F2) of the lower part (la), this terminal portion (IblO) of the extension connection (1b) having a terminal end (Ibl) which is opposite the upper face (F2) of the lower part (la) while being at a distance from this upper face (F2), this end terminal (Ibl) being adapted to abut against the upper face Erieure (F2) to limit a bending amplitude of the prosthetic foot around axes parallel to a main direction of bending (D). 12. Prosthetic leg according to claim 11, wherein said terminal end (Ibl) to abut against the upper face (F2) (Pt) of this upper face (F2) which is adapted at a point distant from a front end (lalO) of the prosthetic foot between 25% and 50% of a total length of the prosthetic foot measured between a rear end (la20) of the prosthetic foot and said front end (lalO). 13. Prosthetic foot according to any one of claims 11 or 12, wherein the terminal ends (T1, T2) of said first wire are located in the terminal portion (IblO). 14. Prosthetic leg according to claim 13, in which the terminal ends (T1, T2) of said first wire are: - closer to the front face (F3) than to the rear face (F4); and - closer to the upper face F2 than to the lower face Fl. 15. Prosthetic foot according to any one of claims 11 to 14, wherein said upper surface portion (lb2) has perforations (lb3a, lb3b) for fixing said apparatus, these perforations (lb3a, lb3b) passing entirely through the connection extension (1b) and the connection extension having at least a third wire (33) disposed exclusively between two of these perforations (lb3a, lb3b) and forming a closed loop in a longitudinal section plane of these two perforations (lb3a , lb3b). 16. A method of manufacturing a prosthetic foot according to any one of claims 1 to 15, comprising the formation of successive layers allowing at least to generate said core and said closed contour, said at least one first wire extending along of the closed contour being deposited between two of these successive layers. 17. The method of claim 16, wherein during the formation of successive layers, reinforcing son (40) are deposited against some of these successive layers so that each of the reinforcing son (40) thus deposited is found between two of these successive layers which are adjacent to it and against which it is in contact, at least some of these reinforcing wires (40) also being taken inside the core (N) of the prosthetic foot thus formed . 18. The method of claim 17, wherein each of the successive layers extends in a plane which is specific to it and which is perpendicular to more or less 20 ° near angle to a support plane stable (P) of the prosthetic foot defined by points on the underside of the prosthetic foot, these successive layers being parallel to each other.