Artificial ankle-foot devices, especially those of the biomimetic type

Abstract

The present invention relates to a prosthetic ankle-foot device (1), in particular to a prosthetic ankle-foot device (1) of the biomimetic type. A particular feature of the present invention is that the system (1) -Tibial element (10) a talar component (20) operatively connected to the tibial component (10) via a first talar joint (A1) comprising a first hinge joint; a calcaneal component (30) operatively connected to the talar component (20) via a second subtalar joint (A2) comprising a second hinge joint; a medial metatarsal element (40) operatively connected to the calcaneal element (30) via a third medial transverse tarsal joint (A3), said third joint (A3) comprising a third hinge joint; a lateral metatarsal element (50) operatively connected to the calcaneal element (30) via a fourth lateral transverse tarsal joint (A4), said fourth joint (A4) comprising a fourth hinge joint; a medial phalangeal element (60) operatively connected to the medial metatarsal element (40) via a fifth medial metatarsophalangeal joint (A5), said fifth joint (A5) comprising a fifth hinge joint; a lateral phalangeal element (70) operatively connected to the lateral metatarsal element (50) via a sixth lateral metatarsophalangeal joint (A6), said sixth joint (A6) comprising a sixth hinge joint; - in comprising an elastic actuation element (80) comprising an upper part operatively connected to the tibial element (10) and a lower part operatively connected to the calcaneal element (30).

Description

[Technical Field]

[0001] The present invention relates to a prosthetic ankle-foot device according to the preamble of claim 1, in particular a prosthetic ankle-foot device of the biomimetic type. [Background technology]

[0002] Several types of prosthetic ankle-foot devices are known in the art, which can be divided into three broad categories: conventional foot (CF), energy storing and returning feet (ESR), and bionic foot (BIO).

[0003] The first conventional foot did not have a centralized degree of freedom and was therefore unable to perform physiological movements. Its main function was to attenuate the forces generated by the impact of the foot on the ground and transmit them to the tibia.

[0004] The energy storage and return foot may be either a single-joint type with one degree of freedom, typically corresponding to the ankle (or torso) joint, or a multi-joint type, allowing the prosthesis to move around different joint axes that correspond more or less to physiological movements.

[0005] Bionic feet can be divided into two types: stabilizing (also called "semi-active") bionic feet and propulsive (also called "active") bionic feet. In the former, active components (usually consisting of motors) serve to adjust some of the characteristics of the prosthesis, such as the ankle stiffness or the foot angle, in order to adapt to different slopes. In the latter, active components serve to supply power to the joints (especially the talocrural joint), thus moving the prosthesis according to a given control logic.

[0006] Currently, most commercially available prosthetic devices belong to the energy storage and return foot (ESR) category, as only a few stabilizing bionic prostheses and only one propulsion bionic prosthesis are currently commercially available.

[0007] A typical commercially available prosthesis corresponds to an ankle-foot assembly and includes a main element made of a deformable material, e.g., a carbon fiber sheet, which allows relative movement between the foot and leg due to the deformability of the material.

[0008] Most prostheses currently under research and development only have one degree of freedom, typically associated with the ankle (i.e., the talocrural joint), as the foot is usually considered a secondary, non-functional element.

[0009] It is therefore clear that such artificial devices are optimized by genetic evolution and therefore do not allow achieving a mechanical behavior of the prosthesis comparable to that of a biological ankle-foot system, which represents an optimal trade-off between different functionalities such as, for example, adaptability to different grounds (thanks to the large number of joints), propulsive capacity (due to the presence of muscles), and energy efficiency (due to the presence of elastic elements that can store and release energy).

[0010] It must also be pointed out that people who have suffered an amputation and wear lower limb prosthetic devices establish compensatory mechanisms that may result in asymmetries in gait and lead to the development of secondary disorders (osteoarthritis, osteoporosis, etc.) and / or higher metabolic energy expenditure, inevitably resulting in increased fatigue.

[0011] In this context, US Patent No. 10,292,840 relates to a passive prosthetic device composed of several parts. In fact, the device described in document US Patent No. 10,292,840 comprises a phalanx part, a metatarsal part operatively connected to the phalanx part, an ankle part operatively connected to the phalanx part, and a calcaneus part operatively connected to the ankle part, the respective connections between the parts of the device being made by torsion springs.

[0012] Although the foot is considered a functional element in document US Pat. No. 10,292,840, the prosthetic device described in such document also has some drawbacks.

[0013] In particular, such drawbacks result from the fact that the phalangeal and metatarsal parts made according to the teachings of document US Pat. No. 10,292,840 consist of solid, rigid bodies that do not allow the prosthetic device to achieve adequate adaptability to different ground surfaces, especially when such ground surfaces are rough and / or unstable.

[0014] Furthermore, the connection of the device parts by torsion springs does not ensure proper mechanical connection between the ankle anteriorly and the plantar arch, which is a particular feature of the biological ankle-foot complex.

[0015] In this frame, it is a primary object of the present invention to provide a prosthetic ankle-foot device, particularly a biomimetic type prosthetic ankle-foot device, which is designed to overcome the drawbacks of the prior art.

[0016] In particular, one object of the present invention is to provide a prosthetic ankle-foot device that is realized in a way that makes it possible to achieve mechanical behavior comparable to that of the biological ankle-foot system.

[0017] Another object of the present invention is to provide a prosthetic ankle-foot device that offers good adaptability to different ground surfaces and high energy efficiency, realized to provide optimal energy storage and release.

[0018] A further object of the present invention is to provide a prosthetic ankle-foot device designed to minimize the establishment of compensatory mechanisms by the person wearing said device and to avoid any gait asymmetry, thus preventing the development of secondary disorders that result in increased fatigue and / or higher expenditure of metabolic energy.

[0019] Another object of the present invention is to provide a prosthetic ankle-foot device that is realized in such a way that it is possible to evaluate the influence of a single factor or parameter on the specific functionality of the prosthetic device.

[0020] It is yet another object of the present invention to provide a prosthetic ankle-foot device that is inexpensive to manufacture and difficult to set up. [Brief explanation of the drawings]

[0021] Further objects, features and advantages of the present invention will become apparent in light of the following detailed description and the accompanying drawings, which are provided as non-limiting illustrative examples. FIG. 1 is a perspective view of a prosthetic ankle-foot device according to the invention, in particular of the biomimetic type; FIG. 2 is an exploded perspective view of the prosthetic device according to the invention shown in FIG. FIG. 3 is a side view of a prosthetic device according to the invention. FIG. 4 is an exploded side view of the prosthetic device shown in FIG. DETAILED DESCRIPTION OF THE INVENTION

[0022] Referring now to the accompanying drawings, the reference number 1 indicates generally a prosthetic ankle-foot device according to the present invention, in particular a prosthetic ankle-foot device of the biomimetic type.

[0023] According to the present invention, the device 1 comprises a tibial component 10, a talar component 20 operably connected to the tibial component 10 via a first talar joint A1 comprising a first hinge joint, and a calcaneal component 30 operably connected to the talar component 20 via a second subtalar joint A2 comprising a second hinge joint.

[0024] Additionally, device 1 comprises a medial metatarsal element 40 operably connected to calcaneus element 30 via a third medial transverse tarsal joint A3, said third joint A3 comprising a third hinge joint, and device 1 comprises a lateral metatarsal element 50 operably connected to calcaneus element 30 via a fourth lateral transverse tarsal joint A4, said fourth joint A4 comprising a fourth hinge joint.

[0025] The device 1 according to the present invention further comprises a medial phalangeal element 60 operably connected to the medial metatarsal element 40 via a fifth medial metatarsophalangeal joint A5, said fifth joint A5 comprising a fifth hinge joint, and the device 1 comprises a lateral phalangeal element 70 operably connected to the lateral metatarsal element 50 via a sixth lateral metatarsophalangeal joint A6, said sixth joint A6 comprising a sixth hinge joint.

[0026] It should be noted that said hinge joints are preferably implemented as respective hinges, in particular cylindrical hinges.

[0027] The device 1 according to the present invention further comprises an elastic actuating element (indicated generally by reference numeral 80 in the accompanying drawings) having an upper part operably connected to the tibial element 10 and a lower part operably connected to the calcaneal element 30.

[0028] In a preferred embodiment, the tibial component 10 has a fork-like shape and comprises a first arm 11 and a second arm 12 that are substantially parallel to each other.

[0029] According to the invention, it can be seen that the first talocrural joint A1 lies on a first axis X1 and the second subtalar joint A2 lies on a second axis X2, said first axis X1 and second axis X2 (shown in FIG. 1 ) forming an oblique double ankle axis, in particular having a biomimetic orientation and position, so that said oblique double axis resembles the biological ankle complex, i.e. resembles the physiological talocrural and subtalar joints.

[0030] In particular, the talar axis is inclined at approximately 10° relative to the median transverse axis in the frontal (or coronal) anatomical plane, at approximately 6° relative to the median transverse axis in the horizontal (or transverse) plane, and at approximately 42° relative to the sagittal axis in the sagittal plane, and at approximately 16° relative to the horizontal plane.

[0031] Like its biological counterpart, the first talocrural joint A1 is involved in physiological dorsiflexion and plantarflexion movements, i.e., ankle flexion and extension movements, the stiffness of the first talocrural joint A1 is provided by the presence of the actuating element 80, and the range of movement of the first talocrural joint A1 is such that it allows different walking types according to physiological biomechanical patterns, including, but not limited to, walking on flat ground, walking uphill and downhill, and climbing and descending stairs.

[0032] In a preferred embodiment, the first talar joint A1 comprises a first opening 11A associated with the first arm 11 of the tibial element 10 and a second opening 12A associated with the second arm 12 of the tibial element 10, the openings 11A, 12A being connected to a talar pin 21 integral with the talar element 20, and preferably each of the openings 11B, 12B being provided with a bushing, in particular a self-lubricating bushing.

[0033] As far as the second subtalar joint A2 is concerned, it is responsible for pronation and supination movements, just like the corresponding biological joint.

[0034] The second subtalar joint A2 comprises a hole 22 on the talar element 20 connected to a subtalar pin 31 integral with the calcaneal element 30, said hole 22 preferably accommodating at least one bushing, in particular a self-lubricating bushing.

[0035] The second subtalar joint A2 is also realized to have its own stiffness, for this purpose it comprises a subtalar pad 23 arranged between the opposing surfaces of the talar element 20 and the calcaneal element 30, said subtalar pad 23 preferably made from an elastomeric material and made in such a way as to obtain a stiffness of the second subtalar joint A2 that substantially corresponds to the stiffness of their biological counterparts.

[0036] The particular structure of the subtalar pad 23 makes it possible to specifically design the stiffness curve of the second subtalar joint A2 as required, even if it is non-linear.

[0037] The third medial transverse tarsal joint A3 and the fourth lateral transverse tarsal joint A4 are substantially parallel and coaxial with each other, and the joints A3 and A4 lie on substantially coincident third and fourth axes X3 and X4, respectively, which are therefore represented as dashed lines in FIG. 1.

[0038] According to a preferred embodiment, the third medial transverse tarsal joint A3 comprises a first pin 32A integral with the calcaneal element 30, which articulates with a hole 41 present in the proximal part of the medial metatarsal element 40, in particular the hole 41 being associated with at least one radial bearing or self-lubricating bushing.

[0039] Furthermore, the fourth lateral transverse tarsal joint A4 includes a second pin 32B integrated with the calcaneal element 30, which articulates with a hole 51 present in the proximal part of the lateral metatarsal element 50, and in particular said hole 51 is associated with at least one self-lubricating bushing.

[0040] The fifth medial metatarsophalangeal joint A5 and the sixth lateral metatarsophalangeal joint A6 lie on substantially parallel, non-coincident fifth and sixth axes X5 and X6, respectively.

[0041] The fifth medial metatarsophalangeal joint A5 consists of a hinge joint including a medial metatarsophalangeal pin 42 that articulates with at least one first opening 43 present in the distal portion of the medial metatarsal element 40 and a second opening 62 present in an arm 61 extending from the medial phalangeal element 60.

[0042] The sixth lateral metatarsophalangeal joint A6 consists of a hinge joint including a lateral metatarsophalangeal pin 52 that articulates with at least one first opening 53 present in the distal part of the lateral metatarsal element 50 and a second opening 72 present in an arm 71 extending from the lateral phalangeal element 70.

[0043] It is therefore clear that the tibial element 10, the talus element 20, and the calcaneus element 30 find direct biological counterparts in the biological tibia, talus, and calcaneus, respectively. Regarding the medial metatarsal element 40, the lateral metatarsal element 50, the medial phalangeal element 60, and the lateral phalangeal element 70, they are "functional" elements and therefore have no direct biological counterparts. In fact, the medial metatarsal element 40 mimics the function of the first and second biological metatarsals, while the lateral metatarsal element 50 mimics the third, fourth, and fifth biological metatarsals. The same applies to the medial phalangeal element 60 and the lateral phalangeal element 70. This functional division allows for a reduction in the complexity of the device 1 according to the present invention, while simultaneously maintaining the primary functionality of the corresponding biological elements. In particular, the structure of the device 1 according to the present invention allows for the creation of three plantar arches (medial longitudinal, lateral longitudinal, and transverse) and, at the same time, allows for a connection between the plantar arch (transverse ankle joint) and the metatarsophalangeal joint.

[0044] In this frame, the first talar joint A1 and the second subtalar joint A2 constitute the joints of the ankle complex of the device 1 according to the invention and have direct biological counterparts in that they mimic its position and spatial orientation.

[0045] The remaining four joints (i.e., the third medial transverse tarsal joint A3, the fourth lateral transverse tarsal joint A4, the fifth medial metatarsophalangeal joint A5, and the sixth lateral metatarsophalangeal joint A6) constitute the joints of the foot of device 1 according to the present invention and, in that they are functional joints, do not have direct biological counterparts. In this framework, the two transverse tarsal joints A3 and A4 mimic the function of the biological transverse tarsal joint (also called Chopart's joint), which is composed of the calcaneocuboid joint and the talonavicular joint, while the two metatarsophalangeal joints A5 and A6 mimic the biological function of the five biological metatarsophalangeal joints.

[0046] Furthermore, the four joints A3, A4, A5, and A6 constitute a single functional group, similar to the biological foot, where a direct connection exists between the transverse tarsal joint and the metatarsophalangeal joint. Specifically, the complex formed by the calcaneal element 30, the third medial transverse tarsal joint A3, the medial metatarsal element 40, the fifth medial metatarsophalangeal joint A5, and the medial phalangeal element 60 constitutes the medial longitudinal arch. Similarly, the complex formed by the calcaneal element 30, the fourth lateral transverse tarsal joint A4, the lateral metatarsal element 50, the sixth lateral metatarsophalangeal joint A6, and the lateral phalangeal element 70 constitutes the lateral longitudinal arch. Additionally, a transverse (or transversal, or anterior) arch is formed as a result of the presence of a medial longitudinal arch and a lateral longitudinal arch between the head of the medial metatarsal element 40 and the head of the lateral metatarsal element 50.

[0047] As can be seen from the accompanying drawings, the actuating element 80 preferably comprises a spring 81, in particular a coil spring, connected to an upper body 82, which articulates with the tibial element 10 via a swivelable (or pivotable) fork system, allowing two degrees of freedom between said actuating element 80 and the tibial element 10.

[0048] In this respect, it is noted that the pivotable fork system according to the invention comprises a fork-shaped element 90 and a first connecting element allowing a first relative rotational movement between the actuating element 80 and the fork-shaped element 90, said first rotational movement constituting a first degree of freedom between the actuating element 80 and the tibial element 10. In the embodiment shown in the accompanying drawings, said first connecting element comprises a radial bearing 82C associated with the upper body 82 of the actuating element 80, which articulates with a respective pin 91P associated with the arm 91 of the fork-shaped element 90.

[0049] It is further noted that the pivotable fork system according to the invention comprises a second connecting element (indicated by reference numerals 84, 85, 86 and 87 in Figure 2) which allows a second relative rotational movement between the actuating element 80 and the fork-like element 90, said second rotational movement constituting a second degree of freedom between the actuating element 80 and the tibial element 10. Preferably, said second connecting element comprises at least one bearing 84, 85, 86 mounted on the rod 92 of the fork-like element 90 which articulates with at least one respective seat (not shown in the accompanying drawings) associated with the tibial element 10.

[0050] In the embodiment shown in FIG. 2, the second connecting element comprises a plurality of bearings, i.e. a first axial needle bearing 84 acting axially between a circular crown present in the tibial element 10 and a corresponding area present on the castellated nut 87; a radial needle bearing 85 acting radially in the hole of the tibial element 10 in which the rod 92 of the fork-shaped element 90 is housed; a second axial needle bearing 86 acting axially between the circular crown present in the tibial element 10 and the front face of the fork-shaped element 90; It is clear that it has the following features.

[0051] The second connecting element also comprises a locking element 87 coupled to the rod 92 of the forked element 90 to tighten the bearings 84, 85, 86 relative to the tibial element 10; it will be noted, upon observing FIG. 2, that the locking element 87 may possibly consist of a castellated nut associated with a cotter pin (not shown) to prevent it from rotating around the rod 92.

[0052] The lower part of the actuating element 80 articulates with the calcaneus element 30 via a terminal 83 which allows two degrees of freedom between said actuating element 80 and the calcaneus element 30. In the embodiment shown in the accompanying drawings, said terminal 83 articulates with the fork 33 of the calcaneus element 30 and comprises a ball joint 83G associated with an anti-twist element, in particular said anti-twist element comprising a side of the ball joint 83G with an element abutting the inner surface of said fork 33. Such an embodiment makes it possible to lock only the unwanted third degree of freedom of the ball joint 83G, i.e. the degree of freedom corresponding to the twist of the actuating element 80.

[0053] According to a preferred embodiment, the device 1 comprises a motor 100 , in particular of electric type, associated with the upper body 82 of said actuating element 80 , possibly through the intermediation of a reducer 101 .

[0054] It is clear that by providing the motor 100, the prosthetic device 1 of the present invention is active, since it is capable of generating a net positive force.

[0055] In this context, the assembly consisting of actuation element 80 and motor 100 acts simultaneously on both the talocrural and subtalar joints, thus replicating the positioning (i.e., origin and insertion) of the biological soleus muscle, which is a biarticular muscle. It is noted that the particular implementation shown in the accompanying drawings makes it possible to minimize the peak power required from motor 100 to make device 1 perform walking gestures.

[0056] Furthermore, the assembly consisting of actuation element 80 and motor 100 replicates the function of the full set of biological plantar flexors and dorsiflexors. However, unlike biological muscles, this assembly can operate in a desmodromic manner, both pulling (plantar flexion) and pushing (dorsiflexion), and can generate the full force of the plantar flexor (primarily soleus, medial and lateral gastrocnemius) and dorsiflexor (primarily tibialis anterior) complexes.

[0057] It should be noted that, according to the teachings of the present invention, the actuating element 80 is placed in series with the motor 100 in the same way that tendons are in series with active elements (muscles) in their biological counterparts.

[0058] According to a preferred embodiment, the stiffness of actuation element 80, in particular spring 81, should be such as to provide a trade-off between minimizing the peak power of the electric motor during the gait cycle, minimizing the energy consumed by the electric motor during the gait cycle, and the possibility of using the prosthesis with a locked motor (motor turned off). Indeed, it has been observed that the optimal stiffness (minimizing peak power and energy consumption) of an active actuation system including motor 100 corresponds approximately to the optimal stiffness required if device 1 does not include motor 100 and is consequently completely passive (linear regression of the torque vs. ankle angle curve). It should be noted that such optimal stiffness also corresponds approximately to the physiological stiffness of the Achilles tendon (plantar flexor tendon).

[0059] Therefore, the artificial device 1 according to the present invention can be made to operate correctly also in a "passive mode" by preventing the rotation of the electric motor 100 or by constructing the device 1 without associating the motor 100 with the actuating element 80.

[0060] From the above description, it becomes clear that the kinematic mechanism formed by the tibial element 10, the talar element 20, the calcaneal element 30, the actuating element 80 and the fork-like element 90 (and possibly also the motor 100) constitutes a closed-chain spatial kinematic mechanism, as opposed to a planar kinematic mechanism as in prior art devices.

[0061] In this context, the pivotable fork system with two degrees of freedom connecting the upper part of the actuating element 80 to the tibial element 10 and the ball joint reduced to a double cylindrical joint connecting the lower part of the actuating element 80 to the calcaneal element 30 perform a dual function. Firstly, such an embodiment ensures smooth actuation of the system with two degrees of freedom, consisting of the first talar joint A1 and the second subtalar joint A2 coupled to each other, and thus makes it possible to actuate said system with two degrees of freedom between the tibial element 10 and the calcaneal element 30 (as in a biological ankle-foot complex) instead of actuating one degree of freedom at a time using a planar mechanism. Secondly, such an embodiment makes it possible to obtain the aforementioned desmodromic system (even if the mechanism is a spatio-kinematic mechanism), i.e. a system capable of both pulling and pushing.

[0062] According to the invention, the device 1 comprises: a first elastic element 44 that connects the calcaneal element 30 to the medial phalangeal element 60 and is positioned below the medial metatarsal element 40; a second elastic element 54 that connects the calcaneal element 30 to the lateral phalangeal element 70 and is positioned below the lateral metatarsal element 50; Includes.

[0063] The connections between the elastic elements 44, 54 and the calcaneal element 30, medial phalangeal element 60 and lateral phalangeal element 70 are achieved by suitable fastening means, for example respective clamps 44M, 54M.

[0064] The elastic elements 44, 54 serve to replicate the function of the biological plantar fascia in that they provide stiffness to the (medial and lateral) longitudinal plantar arches and allow connection between the transverse tarsal joints A3, A4 and the metatarsophalangeal joints A5, A6.

[0065] In a preferred embodiment, the device 1 comprises a first system 45, 46 for adjusting the tension of the first elastic element 44 and a second system 55, 56 for adjusting the tension of the second elastic element 54.

[0066] In particular, the first adjustment system includes a first tensioner 45 connected to the first elastic element 44 and associated with a first adjustment screw 46, and the first tensioner 45 is slidable relative to the calcaneal element 30 to increase or decrease the tension of the first elastic element 44.

[0067] Further, the second adjustment system includes a second tensioner 55 connected to the second elastic element 54 and associated with a second adjustment screw 56, and the second tensioner 55 is slid against the calcaneus element 30 to increase or decrease the tension of the second elastic element 54.

[0068] The adjustment system allows for calibrating and adjusting the stiffness curves of the plantar arch and metatarsophalangeal joints A5, A6 depending on, for example, the person's weight, the operating mode of the device 1 (walking on level ground, walking on rough ground, etc.), or the user's preferences.

[0069] Preferably, the underside of the medial metatarsal element 40 has a first arm 47 on which the first elastic element 44 is mounted, and the underside of the lateral metatarsal element 50 has a second arm 57 on which the second elastic element 54 is mounted.

[0070] The first arm 47 and second arm 57 have several purposes in that they allow: Preventing the plantar arch from collapsing is achieved by keeping the leverage between the elastic elements 44, 54 and the transverse tarsal joints A3, A4 substantially constant as the arch lowers. - Accurately setting the stiffness of the plantar arch (and therefore the metatarsophalangeal joints A5, A6) by properly designing the kinematics. - Leaving sufficient space for the insertion of suitable elements for locking the transverse tarsal joints A3, A4, as will be described below.

[0071] According to a preferred embodiment, the medial phalangeal element 60 comprises a first cam 63 (visible in FIG. 4) on which the first elastic element 44 is mounted, and the lateral phalangeal element 70 comprises a second cam 73 (also visible in FIG. 4) on which the second elastic element 54 is mounted, the first cam 63 and the second cam 73 being realizable to precisely design the stiffness curves of the fifth medial metatarsophalangeal joint A5 and the sixth lateral metatarsophalangeal joint A6. In effect, by changing the radii of the cams 63, 73 it is possible to modify the torsional stiffness of the respective joints A5, A6.

[0072] Preferably, the device 1 according to the invention is realized with at least one locking element for each of the ankle joints A3, A4, A5, A6.

[0073] In particular, device 1 a first pin (not shown) passing through a hole in the first arm 47 and through another hole in the calcaneal element 30 for locking the third medial transverse tarsal joint A3; a second pin (not shown) passing through a hole in the second arm 57 and through another hole in the calcaneal element 30 for locking the fourth lateral transverse tarsal joint A4; a first strap, in particular a peg-shaped one (not shown), fixed between the distal part of the medial metatarsal element 40 and the medial phalangeal element 60 in order to lock the fifth medial metatarsophalangeal joint A5; a second strap, in particular a peg-shaped one (not shown), fixed between the distal part of the lateral metatarsal element 50 and the lateral phalangeal element 70 in order to lock the sixth lateral metatarsophalangeal joint A6; may include:

[0074] The possibility to selectively lock the ankle joints A3, A4, A5, and A6 allows for precise and detailed quantification of the influence each has on the critical functions of the device.

[0075] According to a preferred embodiment, the device 1 according to the invention is realized to comprise at least one sensor 10E, 10I, 30P, 40P, 50P, 60P, 70P associated with at least one joint A1, A2, A3, A4, A5, A6 for providing a direct reading of data relating to such joint.

[0076] In particular, the device 1 according to the invention is preferably realized to comprise one or more of the following sensors (seen in particular in FIG. 2): an encoder 10E fastened to the tibial element 10 at the first joint A1 to read the talar joint angle, said encoder 10E being in particular of the magnetic type and being arranged inside a removable support 10S fastened to the tibial element 10 by fastening means in particular; an inertial sensor 10I fastened to the tibial element 10 at the first talocrural joint A1 to read the absolute tibial angle, said inertial sensor 10I being housed in particular in the same support 10S as the encoder 10E; a first potentiometer 30P fastened to the calcaneal element 30 at the second joint A2 to read the subtalar joint angle; a second potentiometer 40P fastened to the medial metatarsal element 40 at the third joint A3 to read the medial transverse tarsal angle; a third potentiometer 50P fastened to the lateral metatarsal element 50 at the fourth joint A4 to read the lateral transverse tarsal angle; a fourth potentiometer 60P fastened at the fifth joint A5 to read the medial metatarsophalangeal angle, said fourth potentiometer 60P being fastened in particular to the medial metatarsal element 40; a fifth potentiometer 70P fastened at the sixth joint A6 to read the lateral metatarsophalangeal angle, said fifth potentiometer 70P being fastened in particular to the lateral metatarsophalangeal element 50;

[0077] The measurements taken by sensors 10E, 10I, 30P, 40P, 50P, 60P, 70P allow direct reading of all six (relative) joint angles in real time, as well as reading the absolute angle of the tibial component 10 relative to the global reference system, e.g., with respect to pitch and roll.

[0078] The data obtained in this way can be used for different purposes, including creating a robust (because it is based on multiple input data) control model for the motor 100, creating regression models to estimate all the kinematic and kinetic quantities of the artificial device 1 (ground reaction forces, center of pressure trajectory, etc.), assessing the quality of gait of a person using the artificial device 1, etc.

[0079] According to a preferred embodiment, the device 1 according to the invention comprises at least one interface element 34, 64, 74, in particular an interface element made of rubber or a similar material, in order to dampen the impact forces on the ground and ensure optimal grip on the ground.

[0080] In particular, the at least one interface element comprises one or more of the following elements: a first interface element 34 fixed below the calcaneal element 30; a second interface element 64 fixed below the medial phalangeal element 60; a third interface element 74 fixed below the lateral phalangeal element 70; It is therefore apparent that the interface elements 34, 64, 74 are similar to the fat pads found in the biological foot.

[0081] The device 1 according to the present invention has a volumetric size and mass similar to those of its biological counterpart, so that it can be used by amputees even inside normal footwear, and furthermore, the device 1 is easily expandable to obtain different sizes comparable to those of a biological foot.

[0082] The device 1 may be realized with a cover, in particular made of a silicone-based material, to which said device 1 can be attached.

[0083] The device 1 according to the invention further comprises in particular a pyramidal connecting element 110, which makes it possible to connect the device 1 to a tibial pylon (not shown in the accompanying drawings), said connecting element 110 being preferably fixed to the upper part of the tibial element 10.

[0084] The characteristics of the prosthetic ankle-foot device 1 according to the invention, in particular of the biomimetic type, and its advantages are clear from the above description.

[0085] In fact, the device 1 according to the invention is realized in such a way as to make it possible to achieve a mechanical behavior that is comparable to that of the biological ankle-foot system.

[0086] Furthermore, the present invention provides a prosthetic ankle-foot device 1 that offers good adaptability to different ground surfaces and high energy efficiency, designed to provide propulsion capabilities and suitable energy storage and release.

[0087] The particular characteristics of the device 1 according to the invention make it possible to minimize the establishment of compensation mechanisms by the wearer of said device; in particular, the prosthetic ankle-foot device 1 prevents gait asymmetries and therefore avoids higher expenditure of metabolic energy that leads to the development of secondary disabilities and / or increased fatigue.

[0088] The provision of the prosthetic ankle-foot device 1 with sensors 10E, 10I, 30P, 40P, 50P, 60P, 70P allows for accurate quantification of the effect of a single factor or parameter on certain important functions of the device 1.

[0089] In addition to having a volumetric size and mass similar to that of its biological counterpart, allowing it to be used by amputees even inside normal footwear, the prosthetic ankle-foot device 1 according to the present invention is less expensive and easier to set up, and furthermore, the device 1 is easily scalable to obtain different sizes comparable to that of a biological foot.

[0090] It is clear that the prosthetic ankle-foot device 1, in particular of the biomimetic type, described herein by way of example can be subject to many possible variations, and that in a practical implementation of the invention the details shown can have different shapes or be replaced by other technically equivalent elements, without departing from the novel spirit of the inventive idea.

[0091] Therefore, it can be readily understood that the present invention is not limited to the above-described prosthetic ankle-foot device 1, but can be subject to numerous modifications, improvements or substitutions of equivalent parts and elements without departing from the spirit of the present invention, as clearly set forth in the following claims. The following is the invention as originally described in the present application. <Claim 1> An artificial ankle-foot device (1), in particular an artificial ankle-foot device (1) of the biomimetic type, comprising: a tibial element (10); a talar component (20) operatively connected to said tibial component (10) via a first talar joint (A1) comprising a first hinge joint; a calcaneal component (30) operatively connected to said talar component (20) via a second subtalar joint (A2) comprising a second hinge joint; a medial metatarsal element (40) operatively connected to said calcaneal element (30) via a third medial transverse tarsal joint (A3), said third joint (A3) comprising a third hinge joint; and a lateral metatarsal element (50) operatively connected to said calcaneal element (30) via a fourth lateral transverse tarsal joint (A4), said fourth joint (A4) comprising a fourth hinge joint; a medial phalangeal element (60) operatively connected to the medial metatarsal element (40) via a fifth medial metatarsophalangeal joint (A5), the fifth joint (A5) comprising a fifth hinge joint; a lateral phalangeal element (70) operatively connected to the lateral metatarsal element (50) via a sixth lateral metatarsophalangeal joint (A6), the sixth joint (A6) comprising a sixth hinge joint; an elastic actuation element (80) comprising an upper part operatively connected to said tibial component (10) and a lower part operatively connected to said calcaneal component (30); A device (1) comprising: <Claim 2> 2. The device (1) according to claim 1, characterized in that the tibial element (10) has a fork-like shape and comprises a first arm (11) and a second arm (12) that are substantially parallel to each other. <Claim 3> 3. The device (1) according to claim 1 or 2, characterized in that the first talocrural joint (A1) lies on a first axis (X1) and the second subtalar joint (A2) lies on a second axis (X2), the first axis (X1) and the second axis (X2) forming an oblique double ankle axis, in particular with a biomimetic orientation and position. <Claim 4> 4. The device (1) according to claim 3, characterized in that the first talar joint (A1) comprises a first opening (11A) associated with the first arm (11) of the tibial element (10) and a second opening (12A) associated with the second arm (12) of the tibial element (10), the openings (11A, 12A) being connected to a talar pin (21) integral with the talar element (20). <Claim 5> 5. A device (1) according to any one of claims 1 to 4, characterized in that the second subtalar joint (A2) comprises a hole (22) on the talar element (20) connected to a subtalar pin (31) integral with the calcaneal element (30). <Claim 6> 6. A device (1) according to any one of claims 1 to 5, characterized in that the second subtalar joint (A2) comprises a subtalar pad (23) arranged between the opposing surfaces of the talar element (20) and the calcaneal element (30), in particular the subtalar pad (23) being made of an elastomeric material. <Claim 7> 7. The device (1) according to any one of claims 1 to 6, characterized in that the third medial transverse tarsal joint (A3) and the fourth lateral transverse tarsal joint (A4) are substantially parallel and coaxial with each other, and the joints (A3, A4) lie on substantially coincident third and fourth axes (X3, X4), respectively. <Claim 8> 8. The device (1) according to claim 7, characterized in that the third medial transverse tarsal joint (A3) comprises a first pin (32A) integral with the calcaneal element (30), which first pin articulates with a hole (41) present in the proximal part of the medial metatarsal element (40). <Claim 9> 9. A device (1) according to claim 7 or 8, characterized in that the fourth lateral transverse tarsal joint (A4) comprises a second pin (32B) integral with the calcaneal element (30), which second pin articulates with a hole (51) present in the proximal part of the lateral metatarsal element (50). <Claim 10> 10. The device (1) according to any one of claims 1 to 9, characterized in that the fifth medial metatarsophalangeal joint (A5) and the sixth lateral metatarsophalangeal joint (A6) lie on a fifth axis (X5) and a sixth axis (X6), respectively, which are substantially parallel and not coincident. <Claim 11> 11. The device (1) according to claim 10, characterized in that the fifth medial metatarsophalangeal joint (A5) consists of a hinge joint with a medial metatarsophalangeal pin (42) that articulates with at least one first opening (43) present on the distal part of the medial metatarsal element (40) and a second opening (62) present on an arm (61) extending from the medial phalangeal element (60). <Claim 12> 12. The device (1) according to claim 10 or 11, characterized in that the sixth lateral metatarsophalangeal joint (A6) consists of a hinge joint with a lateral metatarsophalangeal pin (52) that articulates with at least one first opening (53) present on the distal part of the lateral metatarsal element (50) and a second opening (72) present on an arm (71) extending from the lateral phalangeal element (70). <Claim 13> 13. The device (1) according to any one of claims 1 to 12, characterized in that the actuating element (80) comprises a spring (81) connected to an upper body (82) that articulates with the tibial element (10) via a pivotable fork system that allows two degrees of freedom between the actuating element (80) and the tibial element (10). <Claim 14> The pivotable fork system - a fork-shaped element (90), a first connecting element that allows a first relative rotational movement between said actuation element (80) and said fork-shaped element (90); - second connecting elements (84, 85, 86, 87) that allow a second relative rotational movement between said actuating element (80) and said fork-shaped element (90); 14. The device (1) according to claim 13, characterized in that it comprises: <Claim 15> 15. The device (1) according to claim 14, characterized in that the first connecting element comprises a radial bearing (82C) associated with the upper body (82) of the actuating element (80), which radial bearing articulates with a respective pin (91P) associated with an arm (91) of the fork-shaped element (90). <Claim 16> 16. The device (1) according to claim 14 or 15, characterized in that the second connecting element comprises at least one bearing (84, 85, 86) attached to a rod (92) of the fork-shaped element (90), the rod articulating with at least one respective seat associated with the tibial element (10). <Claim 17> 17. A device (1) according to any of the preceding claims, characterized in that the lower part of the actuating element (80) articulates with the calcaneus element (30) via a terminal (83) that allows two degrees of freedom between the actuating element (80) and the calcaneus element (30). <Claim 18> 18. The device (1) according to claim 17, characterized in that the terminal (83) articulates with the fork (33) of the calcaneus element (30) and comprises a ball joint (83G) associated with an anti-twist element, in particular the anti-twist element comprising a side of the ball joint (83G) with an element abutting the inner surface of the fork (33). <Claim 19> A device (1) according to any of the preceding claims, characterized in that the device (1) comprises a motor (100) associated with the upper body (82) of the actuating element (80), in particular through the intermediation of a reducer (101). <Claim 20> The device (1) a first elastic element (44) connecting the calcaneal element (30) to the medial phalangeal element (60) and positioned below the medial metatarsal element (40); a second elastic element (54) connecting said calcaneal element (30) to the lateral phalangeal element (70) and positioned under said lateral metatarsal element (50); A device (1) according to any one of claims 1 to 19, characterized in that it comprises: <Claim 21> 21. The device (1) according to any one of claims 1 to 20, characterized in that the device (1) comprises a first system (45, 46) for adjusting the tension of the first elastic element (44) and a second system (55, 56) for adjusting the tension of the second elastic element (54). <Claim 22> 22. A device (1) according to any one of claims 1 to 21, characterized in that the underside of the medial metatarsal element (40) comprises a first arm (47) on which the first elastic element (44) is mounted, and the underside of the lateral metatarsal element (50) comprises a second arm (57) on which the second elastic element (54) is mounted. <Claim 23> 23. A device (1) according to any one of claims 20 to 22, characterized in that the medial phalangeal element (60) comprises a first cam (63), which is mounted on the first elastic element (44), and the lateral phalangeal element (70) comprises a second cam (73), which is mounted on the second elastic element (54). <Claim 24> 24. The device (1) according to any one of claims 1 to 23, characterized in that the device (1) comprises locking elements for the third joint (A3) and / or the fourth joint (A4) and / or the fifth joint (A5) and / or the sixth joint (A6). <Claim 25> 25. The device (1) according to any one of claims 1 to 24, characterized in that the device (1) comprises at least one sensor (10E, 10I, 30P, 40P, 50P, 60P, 70P) associated with at least one joint (A1, A2, A3, A4, A5, A6) for providing a direct reading of data relating to said joint (A1, A2, A3, A4, A5, A6). <Claim 26> The device (1) an encoder (10E), in particular of the magnetic type, fastened to the tibial element (10) at said first joint (A1) for reading the talar joint angle, said encoder (10E) being positioned in particular on the inside of a bearing (10S) fastened to said tibial element (10) by fastening means; an inertial sensor (10I) fastened to the tibial element (10) at the first talocrural joint (A1) to read the absolute tibial angle, in particular said inertial sensor (10I) housed in the support (10S) of said encoder (10E); a first potentiometer (30P) fastened to the calcaneal element (30) at the second joint (A2) for reading the subtalar joint angle; a second potentiometer (40P) fastened to the medial metatarsal element (40) at the third joint (A3) for reading the medial transverse tarsal angle; a third potentiometer (50P) fastened to the lateral metatarsal element (50) at the fourth joint (A4) for reading the lateral transverse tarsal angle; a fourth potentiometer (60P) fastened to the fifth joint (A5) for reading the medial metatarsophalangeal angle, in particular the fourth potentiometer (60P) fastened to the medial metatarsal element (40); and a fifth potentiometer (70P) fastened to the sixth joint (A6) for reading the lateral metatarsophalangeal angle, in particular the fifth potentiometer (70P) fastened to the lateral metatarsophalangeal element (50); 26. Device (1) according to claim 25, characterized in that it comprises one or more sensors of the following: <Claim 27> Device (1) according to any of the preceding claims, characterized in that the device (1) comprises at least one interface element (34, 64, 74), in particular made of rubber, to dampen ground impact forces and ensure optimal grip on the ground. <Claim 28> A device (1) according to any of the preceding claims, characterized in that the device (1) comprises a connecting element (110), in particular of pyramidal shape, which makes it possible to connect the device (1) to a tibial pylon.

Claims

1. An artificial ankle-foot device (1), in particular an artificial ankle-foot device (1) of the biomimetic type, comprising: - a tibial element (10), a talar component (20) operatively connected to said tibial component (10) via a first talar joint (A1) comprising a first hinge joint; a calcaneal element (30) operatively connected to said talar element (20) via a second subtalar joint (A2) comprising a second hinge joint; a medial metatarsal element (40) operatively connected to said calcaneal element (30) via a third medial transverse tarsal joint (A3), said third joint (A3) comprising a third hinge joint; a lateral metatarsal element (50) operatively connected to said calcaneal element (30) via a fourth lateral transverse tarsal joint (A4), said fourth joint (A4) comprising a fourth hinge joint; a medial phalangeal element (60) operatively connected to said medial metatarsal element (40) via a fifth medial metatarsophalangeal joint (A5), said fifth joint (A5) comprising a fifth hinge joint; a lateral phalangeal element (70) operatively connected to said lateral metatarsal element (50) via a sixth lateral metatarsophalangeal joint (A6), said sixth joint (A6) comprising a sixth hinge joint; an elastic actuation element (80) comprising an upper part operatively connected to said tibial element (10) and a lower part operatively connected to said calcaneal element (30); A device (1) comprising:

2. 2. The device (1) according to claim 1, characterized in that the tibial element (10) has a fork-like shape and comprises a first arm (11) and a second arm (12) that are substantially parallel to each other.

3. 3. The device (1) according to claim 1 or 2, characterized in that the first talocrural joint (A1) lies on a first axis (X1) and the second subtalar joint (A2) lies on a second axis (X2), the first axis (X1) and the second axis (X2) forming an oblique double ankle axis, in particular with a biomimetic orientation and position.

4. 4. The device (1) according to claim 3, characterized in that the first talar joint (A1) comprises a first opening (11A) associated with the first arm (11) of the tibial element (10) and a second opening (12A) associated with the second arm (12) of the tibial element (10), said openings (11A, 12A) being connected to a talar pin (21) integral with the talar element (20).

5. A device (1) according to any one of claims 1 to 4, characterized in that the second subtalar joint (A2) comprises a hole (22) on the talar element (20) connected to a subtalar pin (31) integral with the calcaneal element (30).

6. A device (1) according to any one of claims 1 to 5, characterized in that the second subtalar joint (A2) comprises a subtalar pad (23) arranged between the opposing surfaces of the talar element (20) and the calcaneal element (30), in particular the subtalar pad (23) being made of an elastomeric material.

7. 7. The device (1) according to any one of claims 1 to 6, characterized in that the third medial transverse tarsal joint (A3) and the fourth lateral transverse tarsal joint (A4) are substantially parallel and coaxial with each other, said joints (A3, A4) lying respectively on substantially coincident third and fourth axes (X3) and (X4).

8. 8. The device (1) according to claim 7, characterized in that the third medial transverse tarsal joint (A3) comprises a first pin (32A) integral with the calcaneal element (30), which first pin articulates with a hole (41) present in the proximal part of the medial metatarsal element (40).

9. 9. A device (1) according to claim 7 or 8, characterized in that the fourth lateral transverse tarsal joint (A4) comprises a second pin (32B) integral with the calcaneal element (30), said second pin articulating with a hole (51) present in the proximal part of the lateral metatarsal element (50).

10. 10. The device (1) according to any one of claims 1 to 9, characterized in that the fifth medial metatarsophalangeal joint (A5) and the sixth lateral metatarsophalangeal joint (A6) lie on fifth and sixth axes (X5) and (X6), respectively, which are substantially parallel and not coincident.

11. 11. The device (1) according to claim 10, characterized in that the fifth medial metatarsophalangeal joint (A5) consists of a hinge joint with a medial metatarsophalangeal pin (42) that articulates with at least one first opening (43) present on the distal part of the medial metatarsal element (40) and a second opening (62) present on an arm (61) extending from the medial phalangeal element (60).

12. 12. The device (1) according to claim 10 or 11, characterized in that the sixth lateral metatarsophalangeal joint (A6) consists of a hinge joint with a lateral metatarsophalangeal pin (52) that articulates with at least one first opening (53) present on the distal part of the lateral metatarsal element (50) and a second opening (72) present on an arm (71) extending from the lateral phalangeal element (70).

13. A device (1) according to any of the preceding claims, characterized in that the actuating element (80) comprises a spring (81) connected to an upper body (82) that articulates with the tibial element (10) via a pivotable fork system that allows two degrees of freedom between the actuating element (80) and the tibial element (10).

14. The swivel fork system - a fork-shaped element (90), a first connecting element allowing a first relative rotational movement between said actuation element (80) and said fork-shaped element (90); - second connecting elements (84, 85, 86, 87) enabling a second relative rotational movement between said actuating element (80) and said fork-shaped element (90); 14. The device (1) according to claim 13, characterized in that it comprises:

15. 15. The device (1) according to claim 14, characterized in that the first connecting element comprises a radial bearing (82C) associated with the upper body (82) of the actuating element (80), which radial bearing articulates with a respective pin (91P) associated with an arm (91) of the fork-shaped element (90).

16. 16. The device (1) according to claim 14 or 15, characterized in that the second connecting element comprises at least one bearing (84, 85, 86) attached to a rod (92) of the fork-shaped element (90), said rod articulating with at least one respective seat associated with the tibial element (10).

17. A device (1) according to any of claims 13 to 16, characterized in that the lower part of the actuating element (80) articulates with the calcaneal element (30) via a terminal (83) that allows two degrees of freedom between the actuating element (80) and the calcaneal element (30).

18. 18. The device (1) according to claim 17, characterized in that the terminal (83) articulates with the fork (33) of the calcaneus element (30) and comprises a ball joint (83G) associated with an anti-twist element, in particular the anti-twist element comprising a side of the ball joint (83G) with an element abutting the inner surface of the fork (33).

19. The device (1) according to any one of claims 13 to 18, characterized in that the device (1) comprises a motor (100) associated with the upper body (82) of the actuating element (80), in particular through the intermediation of a reducer (101).

20. The device (1) a first elastic element (44) connecting said calcaneal element (30) to said medial phalangeal element (60) and positioned under said medial metatarsal element (40); a second elastic element (54) connecting said calcaneal element (30) to the lateral phalangeal element (70) and positioned under said lateral metatarsal element (50); A device (1) according to any of the preceding claims, characterized in that it comprises:

21. 21. The device (1) according to claim 20, characterized in that the device (1) comprises a first system (45, 46) for adjusting the tension of the first elastic element (44) and a second system (55, 56) for adjusting the tension of the second elastic element (54).

22. 22. The device (1) according to claim 20 or 21, characterized in that the underside of the medial metatarsal element (40) comprises a first arm (47) on which the first elastic element (44) is mounted, and the underside of the lateral metatarsal element (50) comprises a second arm (57) on which the second elastic element (54) is mounted.

23. A device (1) according to any of claims 20 to 22, characterized in that the medial phalangeal element (60) comprises a first cam (63), which is mounted on the first elastic element (44), and the lateral phalangeal element (70) comprises a second cam (73), which is mounted on the second elastic element (54).

24. The device (1) according to any of the preceding claims, characterized in that the device (1) comprises locking elements for the third joint (A3) and / or the fourth joint (A4) and / or the fifth joint (A5) and / or the sixth joint (A6).

25. 25. The device (1) according to any of the preceding claims, characterized in that the device (1) comprises at least one sensor (10E, 10I, 30P, 40P, 50P, 60P, 70P) associated with at least one joint (A1, A2, A3, A4, A5, A6) for providing a direct reading of data relating to said joint (A1, A2, A3, A4, A5, A6).

26. The device (1) an encoder (10E), in particular of the magnetic type, fastened to the tibial element (10) at said first joint (A1) for reading the talar joint angle, said encoder (10E) being positioned in particular inside a bearing (10S) fastened to said tibial element (10) by fastening means; an inertial sensor (10I) fastened to the tibial element (10) at the first talocrural joint (A1) to read the absolute tibial angle, in particular said inertial sensor (10I) housed in the support (10S) of said encoder (10E); a first potentiometer (30P) fastened to the calcaneal element (30) at the second joint (A2) to read the subtalar joint angle; a second potentiometer (40P) fastened to the medial metatarsal element (40) at the third joint (A3) to read the medial transverse tarsal angle; a third potentiometer (50P) fastened to the lateral metatarsal element (50) at the fourth joint (A4) to read the lateral transverse tarsal angle; a fourth potentiometer (60P) fastened to the fifth joint (A5) for reading the medial metatarsophalangeal angle, in particular the fourth potentiometer (60P) fastened to the medial metatarsal element (40); and a fifth potentiometer (70P) fastened to the sixth joint (A6) for reading the lateral metatarsophalangeal angle, in particular the fifth potentiometer (70P) fastened to the lateral metatarsal element (50); 26. Device (1) according to claim 25, characterized in that it comprises one or more sensors of the following:

27. Device (1) according to any of the preceding claims, characterized in that the device (1) comprises at least one interface element (34, 64, 74), in particular made of rubber, to dampen the impact forces on the ground and ensure optimal grip on the ground.

28. The device (1) according to any of the preceding claims, characterized in that said device (1) comprises a connecting element (110), in particular of pyramidal shape, making it possible to connect said device (1) to a tibial pylon.

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