Assistive device for a human lower limb.

Abstract

Assistive device for a human lower limb. The invention relates to a walking assistance device (100) for a lower limb (J1) of a human, comprising at least: - a proximal element (110) extending along a longitudinal axis (X), - a distal element (120) comprising at least a part (121) movable relative to the proximal element, - a joint (130) connecting the distal element (120) to the proximal element (110), and comprising at least one cable (131), the joint (130) being able to take at least one free mode in which the distal element is movable in rotation relative to the proximal element around an axis of rotation (R) of the joint (130) and a constrained mode in which the proximal element (110) and the distal element (120) are linked in rotation to each other, the tensioning of the cable (131) causing the change from the free mode to the constrained mode. Figure from the summary: Fig 4B

Description

Title of the invention: Assistive device for a human lower limb. technical field

[0001] The present invention relates to the field of walking assistance devices, and in particular to the field of orthoses and exoskeletons intended for the lower limbs of human beings. Previous technique

[0002] To assist people with joint problems in walking, the use of orthotics has been known for several years. These devices are positioned around the lower limbs and stabilize the joints while allowing their movement to enable walking. Recent years have also seen the development of exoskeletons, which are more complex than the orthotics used until now. These exoskeletons can also be used to equip people without joint problems, for example, to provide assistance when carrying heavy loads. These exoskeletons most often reinforce one or more of the joints of the affected lower limb, namely the ankle and / or knee and / or hip.

[0003] Several drawbacks exist with current exoskeletons. In particular, the majority of these exoskeletons are active, meaning their movements are controlled by motors, which adds weight to the device and makes it very bulky. Controlling these motors can also be complex and prone to failure.

[0004] Also, the joints of current exoskeletons are most often indexed, that is to say they are designed to be locked according to a number of predefined angular positions, which is not necessarily suitable for all the situations that people who use this type of device may encounter.

[0005] Documents FR3074078 and FR3096600 describe, respectively, a lower limb exoskeleton that incorporates an electromagnet system for locking at least one joint of the exoskeleton. The electromagnets are associated with various elements that enable the joint locking. A drawback of these systems is that they require a power supply.

[0006] US patent 10039685 describes a lower limb exoskeleton that is configured to resist knee flexion up to a certain angle beyond which flexion is instead facilitated.

[0007] US patent 10342723 describes a lower limb exoskeleton in which the movements of the joints are controlled by motors, these joints being able to be locked by notching according to a number of predefined positions.

[0008] There is therefore a need to improve assistance solutions for a human lower limb, in particular by allowing angular locking of the joints, without the need for motorization.

[0009] The aim of the present invention is to meet at least partially this need. Summary of the invention

[0010] To this end, an object of the invention relates to a walking assistance device for a human lower limb, comprising at least - a proximal element extending along a longitudinal axis, - a distal element comprising at least one part movable relative to the proximal element, - a joint linking the distal element to the proximal element, and comprising at least one cable configured to be put under tension by a translation of the movable part of the distal element, in the direction of the proximal element and the joint being able to take at least one free mode in which the distal element is mobile in rotation relative to the proximal element around an axis of rotation of the joint, and a constrained mode in which the proximal element and the distal element are linked in rotation with each other, the tensioning of the cable causing the transition from the free mode to the constrained mode.

[0011] For example, the axis of rotation of the joint is a transverse axis, perpendicular to the longitudinal axis of the proximal element. Thus, the walking assistance device makes it possible to accompany the movements of an ankle or a knee, for example.

[0012] The assistance device is thus, for example, adapted to be positioned around a human lower limb so that the joint is positioned opposite an ankle of that lower limb. The device is then positioned so that the proximal element comes around a calf of the lower limb and the distal element comes around a foot of that lower limb.

[0013] According to an advantageous embodiment of the invention, the distal element is further connected to the proximal element by at least one elastic return means when the joint is in constrained mode, and the joint comprises at least one drum movable about the axis of rotation of the joint in free mode, the elastic return means comprising at least one attachment means that cooperates with the drum. This elastic return means may, in certain cases, participate in the release of the cable that allows the joint to transition from constrained mode to free mode. According to various examples of the invention detailed below, the attachment means is fixed to the drum, or wrapped around this drum.

[0014] Optionally, the distal element can be connected to the proximal element by at least two elastic return means when the joint is in constrained mode. For example, each elastic return means includes a hook that cooperates with the drum. The choice of stiffness and tension of the elastic return means determines the assistance torque of the device. Thus, the higher the stiffness and tension (without reaching the maximum limit set by the user's weight and / or the load) of these means, the greater the assistance provided by the device to its user.

[0015] In this application, "drum" means any element enabling the winding of a cable.

[0016] For example, the distal element may consist solely of a movable part. According to this example, placing the distal element against a support causes a translation of this distal element towards the proximal element, resulting in tensioning of the cable and thus the transition of the joint from free mode to constrained mode. Such a bearing corresponds to a classic phase of walking when the assistive device is fitted to a human lower limb.

[0017] According to one embodiment of the invention, the cable can be loosely wound around the drum when the joint is in its free mode, the cable being guided at least partially by a guide carried on the moving part of the distal element. Then, tensioning the cable causes it to tighten around the drum, ultimately resulting in a locking of the drum and thus of the joint, which is then placed in its constrained mode. In other words, a capstan is used, allowing a gradual transition between the free and constrained modes of the joint.

[0018] According to one embodiment of the invention, the cable constitutes an attachment means for the elastic return means that cooperates with the drum. This first embodiment has the advantage of being particularly simple and inexpensive to implement. If necessary, the cable can constitute the attachment means for both elastic return means that cooperate with the drum.

[0019] According to another example of the invention, the assistance device may include a cylinder, rotationally linked with the moving part of the distal element, the cable being wound around this cylinder, loosely when the joint is in free mode.

[0020] The term "cylinder" is understood in this application as an element enabling the winding of a cable around its external perimeter.

[0021] According to this other example of the invention, the two ends of the cable can, for example, be fixed to the drum, the cable being at least partially guided by a guiding means carried by the moving part of the distal element. The tensioning of the The cable then causes the cylinder to tighten around the drum, resulting in a rotational fixation of the cylinder to the drum. Consequently, the moving part of the distal element is also rotationally fixed to the drum, due to the cable ends being attached to the drum, which is itself rotationally constrained by the elastic return mechanisms. The joint thus enters a constrained state, meaning the distal element is rotationally bound to the proximal element, with a rigidity that depends on the choice of elastic return mechanisms. For example, the two ends of the cable can be fixed to the drum diametrically opposite each other. Advantageously, this allows for balancing the forces applied to the drum when the cable is tensioned.

[0022] Alternatively, the two ends of the cable can be fixed on the moving part of the distal element, the cylinder being rotationally linked with the drum.

[0023] According to another embodiment of the invention, the cylinder can be linked in rotation and translation with the moving part of the distal element, the two ends of the cable being fixed, in a diametrically opposite manner, to the drum.

[0024] According to yet another embodiment of the invention, the joint may comprise a braking element rotationally linked to the drum, and a braking jaw controlled by the tensioning of the cable, the braking jaw being configured to grip the braking element when the cable is tensioned. The braking element may, for example, be a brake disc. The braking jaw may alternatively be formed by brake pads or brake drums without departing from the scope of the present invention. Advantageously, the use of such a braking system allows for a rapid response, that is to say, an instantaneous or near-instantaneous transition of the joint from free mode to constrained mode, and vice versa.

[0025] Alternatively, the joint may comprise a first clutch element fixed to the drum and a second clutch element rotationally linked to the distal element, tensioning the cable causing the first and second clutch elements to engage with each other. As before, this alternative allows for a rapid response, i.e., an instantaneous or near-instantaneous transition of the joint from free to constrained mode, and vice versa.

[0026] According to a different embodiment, the movable part of the distal element may protrude from an underside of the distal element when the joint is in free mode, the assistive device comprising the cylinder and the cable being loosely wound around the cylinder when the joint is in free mode. This embodiment also differs from the preceding ones in that the cylinder is not rotationally bound to the movable part of the distal element. By "underside" is meant here a face of the distal element opposite to the proximal element. In other words, this face lower forms the part of the distal element intended to come into contact with the walking support.

[0027] According to this embodiment, the moving part of the distal element can, for example, be formed by at least one piston. Advantageously, the moving part of the distal element can be formed by at least two pistons.

[0028] Optionally, the walking assistance device according to the invention may include at least one motorized actuation system adapted to drive the drum in rotation.

[0029] The invention essentially consists of a walking assistance device for a human that allows for passive joint stressing, that is, stressing without the intervention of a motor. This assistance device also advantageously allows switching from a free mode to a constrained mode, without the constrained mode being defined by a specific position or a locking range. Furthermore, the transition from free mode to constrained mode is triggered by the weight of the person using the device and therefore does not require a dedicated control device for this transition. The assistance device according to the invention is thus simpler and less expensive to implement compared to prior art devices.

[0030] An object of the present invention further relates to a method of applying stress to a joint by means of an assistance device as described above, which comprises the steps of: - to support the distal element of the assistance device against a support when the joint is in free mode, - put the cable under tension in order to bring the joint into constrained mode.

[0031] Other advantages and features will become clearer upon reading the detailed description, given by way of illustration and not limitation, with reference to the following figures. Brief description of the figures

[0032] [Fig.1] Fig.1 illustrates a walking kinematic of a human;

[0033] [Fig. 2A], [Fig. 2B] Figures 2A and 2B illustrate, schematically and from the front, a walking assistance device according to a first embodiment of the invention, respectively in a free mode and in a constrained mode;

[0034] [Fig. 3A], [Fig. 3B] Figures 3A and 3B illustrate, schematically and from the front, the walking assistance device according to a second embodiment of the invention, respectively in free mode and in constrained mode;

[0035] [Fig.4A], [Fig.4B], [Fig.4C], [Fig.4D] Figures 4A to 4D illustrate, Schematically, the walking assistance device operates according to a third mode of realization of the invention, figures 4A and 4B illustrating front views of the assistance device, respectively in free mode and in constrained mode, [Fig.4C] being a perspective view of the assistance device in constrained mode according to the third realization mode and [Fig.4D] being a representation of the device in constrained mode according to a cross-section;

[0036] [Fig. 5A], [Fig. 5B] Figures 5A and 5B illustrate, schematically and from the front, the walking assistance device according to a fourth embodiment of the invention, respectively in free mode and in constrained mode;

[0037] [Fig. 6A], [Fig. 6B] Figures 6A and 6B illustrate, schematically and from the front, the walking assistance device according to a fifth embodiment of the invention, respectively in free mode and in constrained mode;

[0038] [Fig.7A], [Fig.7B] Figures 7A and 7B illustrate, schematically and from the front, the walking assistance device according to a sixth embodiment of the invention, respectively in free mode and in constrained mode;

[0039] [Fig.8A], [Fig.8B] Figures 8A and 8B illustrate, schematically and from a point of view facing, the walking assistance device according to a seventh embodiment of the invention, respectively in free mode and in constrained mode;

[0040] [Fig.9A], [Fig.9B] Figures 9A and 9B illustrate, schematically and from a point of view on the side, the walking assistance device according to an eighth embodiment of the invention, respectively in free mode and in constrained mode;

[0041] [Fig.1OA], [Fig.1OB], [Fig.1OC], [Fig.1OD] Figures 10A to 10D illustrate, schematically and from the side, the walking assistance device according to a ninth embodiment of the invention, [Fig.1OA] illustrating the free mode and Figures 10B to 10D illustrating the steps to switch from the free mode to the constrained mode;

[0042] [Fig. 11 A], [Fig. 1 IB] Figures 11A and 1 IB illustrate, schematically and from on the side, the walking assistance device according to a tenth embodiment of the invention, respectively in free mode and in constrained mode;

[0043] [Fig. 12] The [Fig. 12] is a partial schematic representation, side view, of a variant of the walking assistance device which can be adapted to any of the embodiments illustrated in Figures 2A to 1 IB. Detailed description

[0044] In the following description and throughout this application, the terms "distal" and "proximal" are used by reference to the body of a human wearing an assistive device according to the invention on one of its lower limbs. Thus, the distal element of the assistive device according to the invention is the element located furthest from the trunk of the human body whose lower limb is equipped with the device.

[0045] It is specified that the different elements are not necessarily represented to scale.

[0046] In all the figures, the same numerical reference designates the same element.

[0047] Fig. 1 schematically illustrates a human walking kinematic. In order not to clutter the figure, the references are only shown on a first silhouette S of an individual among those illustrated, but it is understood that these references are transposable to all of these silhouettes.

[0048] As illustrated, two main alternating phases can be distinguished for each of the lower limbs J1, J2: a stance phase PA and a swing phase PO. During the stance phase PA, the entire body rests temporarily on the first lower limb J1 while the second lower limb J2 is moved forward. The joints of the first lower limb J1—ankle, knee, hip—are then under stress to allow the body to be supported. During the swing phase PO, the body rests on the second lower limb J2, while the first lower limb J1 is lifted off the ground to be placed further along, thus allowing the body to move forward. In this swing phase PO, the joints of the first lower limb J1 must therefore be free to allow the movement of this limb as a whole.

[0049] Figures 2A to 12 schematically illustrate different embodiments of a walking assistance device 100 adapted to be worn by a human lower limb. In the example shown in [Fig. 1], the device is worn by the first lower limb JL

[0050] The assistive device 100 comprises a proximal element 110 extending primarily along a longitudinal axis X and a distal element 120 connected to the proximal element 110 by a joint 130. This joint 130 may have at least one free mode in which it exhibits at least one degree of freedom and a constrained mode in which the proximal element 110 and the distal element 120 are rotationally bound to each other. In the illustrated examples, the distal element 120 is rotationally free about an axis of rotation R of the joint. In the illustrated examples, the axis of rotation R of the joint is a transverse axis T perpendicular to the longitudinal axis X of the proximal element.

[0051] The distal element 120 also includes a part 121 that is movable in translation when approaching or moving away from the proximal element 110.

[0052] The joint 130 comprises at least one cable 131, the tensioning of which causes the joint to switch from the free mode to the constrained mode. Conversely, A release of this cable causes the joint to transition from the constrained mode to the free mode. According to the illustrated embodiments, the tensioning of the cable 131 is caused by the translation of the mobile part 121 of the distal element towards the proximal element 110. Conversely, the release of this cable 131 is caused by the translation of the mobile part 121 of the distal element away from the proximal element 110.

[0053] Finally, the joint 130 comprises at least one drum 132 movable at least about the axis of rotation R of the joint. In other words, according to the examples illustrated here, the drum 132 is rotationally movable about the transverse axis T. The rotation of the drum 132 about the axis of rotation R of the joint is at least partially constrained by the presence of elastic return means. In this application, "drum" means any element allowing a cable to be wound.

[0054] The figures illustrate a particular application of the invention, in which the joint 130 is intended to be positioned opposite the ankle of the lower limb equipped with the device 100, the proximal element 110 being positioned at the calf of this lower limb and the distal element 120 being positioned to support a foot. According to this application, the distal element 120 thus comprises a foot support 122 and a stem 123 extending from the support 122 towards the proximal element 110.

[0055] According to another application example of the invention not illustrated here, the joint is intended to be positioned opposite the knee of the lower limb equipped with the device, the proximal element being positioned at the thigh of this limb and the distal element at the calf. It is understood that, according to this other application example, a shape of the foot support of the distal element described above is adapted to the shape of the calf.

[0056] The device 100 further comprises at least one elastic return means 140 connected on one side to the proximal element 110 and on the other side to the joint 130 by the drum 132. This elastic return means 140 comprises at least one attachment means 141 by which it cooperates with the drum 132. For example, this attachment means 141 is formed by a cable—separate or not from the cable intended to be tensioned for the joint to move into the constrained mode, as detailed below—which can cooperate with the drum by means of a rigid winding or a crimp. It is understood that the attachment means can be formed by any other means known to those skilled in the art and compatible with the invention. Such an elastic return means 140 helps to enable the joint 130 to move from its constrained mode to its free mode.

[0057] As illustrated for example in Figures 4C and 9A to 12, the device 100 comprises two elastic return means 140 arranged on either side of the proximal element 110 and representing, respectively, an agonist muscle and an antagonist muscle of the relevant part of the lower limb. According to this example, each elastic recoil means includes at least one attachment means 141 by which it is fixed to the drum 132.

[0058] If the device 100 is positioned on the ankle, the elastic recoil means 140 allow, in particular, the storage of potential energy during the first part of the stance phase (from the beginning of stance to maximum ankle flexion) of the gait cycle, and its release during the second part of the stance phase (from maximum ankle flexion until the moment of foot lift), thus assisting walking. If the device is positioned on the knee, the recoil means will be particularly useful during squatting, by storing energy during the flexion phase, and thus assisting the return to a standing position.

[0059] These elastic return means 140 can also be used to adjust the rigidity of the force applied by the assistance device 100 to the lower limb wearing it. In other words, these elastic return means 140 allow control of the assistance torque that the device provides to its user.

[0060] With reference to Figures 2A to 4D, we will now describe a first, a second, and a third embodiment. These three embodiments share the structure of the distal element 120. According to these embodiments, the movable part 121 of the distal element 120 is formed by the entire distal element 120 itself. Since the movable part 121 is translationally movable in both directions and away from the proximal element, it is understood that in these embodiments, the entire distal element 120 is translationally movable in both directions and away from the proximal element 110. For example, a slide—not visible in the figures—can be mounted on the rod 123 of the distal element 120 and cooperate with the rotation axis R on which the distal element 120 and the drum 132 mentioned above are mounted for rotation.

[0061] According to the first, second, and third embodiments, the rod 123 of the distal element 120 includes a cable guide 124 for the cable 131. According to the examples illustrated here, this guide 124 may, for example, take the form of a pulley. It is understood that any other guide compatible with the invention may be used without departing from the scope of the invention.

[0062] According to the first and second embodiments illustrated in Figures 2A and 3A, the cable 131 is also loosely wound around the drum 132 when the joint is in its free mode. When the lower limb equipped with the assistance device 100 enters the stance phase PA described with reference to [Fig. 1], the user places their heel against a support, for example the ground, and then their entire foot, the distal element 120, rises towards the element Proximal, meaning that this distal element translates vertically under the weight of the person wearing the support device 100, and, where applicable, the weight of the support device itself—which can optionally carry an additional load. In doing so, it pulls the cable 131 taut via the pulley 124. The cable 131's loose winding around the drum 132 tightens, resulting in stress on the joint 130. The joint 130 is then in its constrained state, maintaining ankle stability, particularly through the elastic recoil means 140, throughout the aforementioned stance phase. At the end of this stance phase, the limb equipped with the device 100 is raised, breaking contact with the support.Due to gravity, the distal element 120 falls away from the proximal element 110, causing the cable 131 to slacken so that its winding around the drum 132 becomes loose again, thus freeing the movements of the joint 130. The operation just described can be compared to the operation of a capstan.

[0063] Optionally, an elastic return element 142 can be added between the axis of rotation R of the joint and the stem 123 of the distal element 120. This elastic return element 142 - for example visible on [Fig.4D] - participates in the falling of the distal element 120 away from the proximal element 110 at the end of the stance phase.

[0064] According to the first embodiment of the assistance device 100 illustrated in Figures 2A and 2B, the cable 131 which, when under tension, allows the transition from the free mode of the joint 130 to the constrained mode constitutes the attachment means 141 of the elastic return means 140 on the drum 132. [Fig.2A] illustrates the device 100 in the free mode while [Fig.2B] illustrates the device 100 in the constrained mode.

[0065] The second embodiment of the assistance device 100 illustrated in Figures 3A – in free mode – and 3B – in constrained mode – differs from the first embodiment in that the cable 131 and the attachment means 141 are separate elements. The attachment means 141 are permanently fixed to the drum 132, and the cable 131 is wound around the drum 132, forming a loop between the drum 132 and the pulley 124. Optionally, the ends of the cable 131 can be fixed to the drum 132 to prevent slippage of the cable 131. The operation of the assistance device 100 according to this second embodiment is otherwise identical to that described above.

[0066] The third embodiment of the assistance device 100 illustrated in Figures 4A to 4D differs from the first and second embodiments in that the joint 130 comprises a cylinder 133 rotationally linked to the distal element 120, and more particularly to the stem 123 of this distal element. By "cylinder," we mean Here, any element enabling the cable winding is shown. Figure 4A illustrates the device viewed from the front in free mode, while Figures 4B to 4D illustrate the device in constrained mode, respectively viewed from the front, in perspective, and in cross-section.

[0067] According to this third embodiment, the drum 131 and the cylinder 133 are both mobile in rotation around the axis of rotation R of the joint 130 when the latter is in free mode.

[0068] According to this third embodiment, the cable 131 is not wound around the drum 132, but around the cylinder 133. More specifically, the cable 131 is loosely wound around the cylinder when the joint 130 is in its free position. The ends 134, 135 of the cable 131 are fixed to the drum 132, for example, diametrically opposite. The rest of the device 100 is identical to that described above, and its operation is also the same, except that tensioning the cable 131 causes it to tighten around the cylinder, blocking its rotation relative to the drum 132, because the cylinder 133 is rotationally linked to the drum 132, at least by the fixing of the cable ends. Since the rotation of this drum is also linked to the elastic return means, the joint 130 is then in its constrained position.

[0069] Figures 5A and 5B illustrate a fourth embodiment of the assistance device 100, which differs from the third embodiment in that the rod 123 lacks the guiding means. According to this fourth embodiment, the cable 131 is also wound around the cylinder 133, but its ends 134, 135 are fixed to the rod 123 of the distal element 120. In particular, and as illustrated, the ends 134, 135 of the cable 131 are fixed to a return 125 of the rod 123 that extends perpendicularly to this rod 123. According to this fourth embodiment, the drum 132 and the cylinder 133 are rotationally linked in both the free and constrained modes. The operation of the device 100 according to this fourth embodiment is identical to the operation described above, that is to say that when the cable 131 is loosely wound around the cylinder 133, the joint 130 is in the free mode, as illustrated in the [Fig.[5A], and the bearing of the distal element 120 against the ground causes the translation of this distal element 120 towards the proximal element, and the tensioning of the cable 131, so that it tightens around the cylinder, thus blocking the rotation of this cylinder and therefore of the drum to which it is rotationally linked. The cylinder being further rotationally linked with the movable part 121 of the distal element 120, the joint 130 then passes into the constrained mode illustrated in [Fig. 5B].

[0070] Figures 6A and 6B illustrate a fifth embodiment of the assistance device 100, [Fig. 6A] illustrating the free mode and [Fig. 6B] illustrating the constrained mode. This fifth embodiment differs from the first embodiment in The cable 131 is not wound around the drum 132, but rather drives a braking system. This braking system comprises a brake element 151 fixed to the drum 132 and a brake jaw 152 connected by the cable 131 to the distal element 120, and more specifically to the rod 123 of the distal element 120. The brake jaw 152 is mounted on the axis of rotation R, and it is constrained in rotation with the rod 123 of the distal element 120. The brake jaw 152 is arranged on either side of the brake element 151, so that when the cable 131 is put under tension by the translation of the distal element 120 towards the proximal element, this brake jaw 152 clamps the brake element 151, thus preventing any movement of the latter. Since the braking element 151 is integral with the drum 132, the blocking of the braking element 152 causes the drum 132 to block, and therefore the joint to pass into the constrained mode.This fifth embodiment allows for an instantaneous, or near-instantaneous, transition from free mode to constrained mode, and vice versa.

[0071] Figures 7A and 7B illustrate a sixth embodiment of the assistance device according to the invention, with [Fig. 7A] illustrating the joint in free mode and [Fig. 7B] illustrating the joint in constrained mode. This sixth embodiment differs from the embodiments described above in that the joint 130 includes a clutch mechanism. In particular, the sixth embodiment differs from the third embodiment in that the cylinder 133 is no longer rotationally linked with the drum 132, but is rotationally linked with the distal element 120, and in particular with the rod 123 of this distal element. This rod 123, and the distal element as a whole, remains, however, translationally mobile in the direction of the proximal element relative to the cylinder 133.The drum 132 is also integral with a first clutch element 161, and the cylinder 133 in this case takes the form of a second clutch element 162. The cable 131 is not wound around the cylinder 133, but when tensioned, allows the cylinder 133 to slide along the axis of rotation R, which brings the drum 132 and the cylinder 133 closer together, allowing the first clutch element 161, integral with the drum 132, to engage with the second clutch element 162 formed by the cylinder 133, thus locking the joint 130. Alternatively, the second clutch element can be separate from the cylinder 133 and integral with it without departing from the scope of the invention.

[0072] Figures 8A and 8B illustrate a seventh embodiment of the assistance device according to the invention, [Fig. 8A] illustrating the joint 130 in free mode and [Fig. 8B] illustrating the joint 130 in constrained mode. This seventh embodiment differs from the third embodiment in that, when the joint is in free mode, the cylinder 133 is no longer rotationally bound to the drum 132, but to the distal element 120. Furthermore, the cylinder 133 according to this seventh embodiment is also linked in translation with the distal element 120. The operation is similar to the operation described with reference to figures 4A and 4B which illustrate the third embodiment, that is to say that the tensioning of the cable 131 causes the latter to tighten around the cylinder 133, thus blocking the rotation of the drum 132, because the ends 134, 135 of the cable 131 are linked to the drum 132.

[0073] Figures 9A to 1 IB illustrate an eighth, a ninth and a tenth embodiment of the assistance device 100 which differ in particular from the embodiments which have just been described, in that the movable part 121 of the distal element 120 protrudes on an under face 126 of this distal element 120, that is to say a face of this distal element 120, and more precisely a face of the foot support 122 of this distal element, which is intended to come into contact with the walking support. In particular, according to these embodiments, the movable part 121 of the distal element 120 takes the form of one or more piston(s) 127 whose movement causes the cable 131 to be tensioned. The joint 130 is otherwise identical to that described with reference to the third embodiment illustrated in figures 4A, 4B, in that it comprises the drum 132 and the cylinder 133, the cable 131 being wound around the cylinder 133.Unlike the third embodiment described above, the cylinder 133 is not rotationally linked to the moving part of the distal element. Similar to what was described above with reference to the third embodiment, the cable 131 is loosely wound around the cylinder 133 in its free mode and is configured to tighten around this cylinder when tensioned, causing the joint to move into the constrained mode.

[0074] The assistance device 100 according to the eighth embodiment illustrated in Figures 9A - in free mode - and 9B - in constrained mode - comprises a single piston 127 equipped with cable guiding means 128 which allow tensioning of this cable 131 when the piston 127 moves upwards towards the proximal element 110. According to the illustrated example, these guiding means 128 are formed by pulleys, but it is understood that this is only an example and that any other guiding means compatible with the invention could be used instead.

[0075] The assistance device 100 according to the ninth embodiment illustrated in Figures 10A to 10D comprises two pistons 127, each equipped with a plurality of cable guiding means 128, allowing for improved stability of the joint 130 at the end of the stance phase, i.e., when the foot is partially lifted off the ground, as schematically illustrated in Figures 10B, 10C, and 10D. Indeed, it can be understood from these Figures 10B to 10D that the use of two pistons 127 ensures at least partial tension of the cable even when only one end—as illustrated in [Fig. 1OB]—or one end—as illustrated in [Fig. 1OD]—of the support foot 122 is supported against the step support. As before, the guiding means 128 are here formed by pulleys, but it is understood that this is only one example of an implementation of the invention.

[0076] The assistance device 100 according to the tenth embodiment illustrated in Figures 1 IA and 1 IB comprises a piston 127 equipped with a shaft 128, which eliminates the need for the pulleys used in the eighth and ninth embodiments. In other words, this shaft forms the guide means for the cable 131.

[0077] Finally, as schematically illustrated in [Fig. 12], the assistance device 100 may include a motorized actuation system, in addition to the elastic return means 140. This system includes a motor 170 that drives a screw 171 in rotation, which translates a nut 172 around the screw. The translation of the nut 172 causes a drive belt 173, to which the nut is attached, to wind around the drum 132, and thus rotates the latter. It is understood that although this motorized actuation system is illustrated with an assistance device 100 in which the joint 130 comprises both a drum 132 and a cylinder 133, it may be added to any of the devices previously described and illustrated.

[0078] As will be apparent from this description, the invention thus makes it possible to propose a walking assistance device that adapts to the walking phase, thanks to the simple weight of the body applied to the joint in question. The walking assistance device according to the invention can also advantageously be used with a motor; that is to say, this assistance device can be exclusively passive, or partially active.

[0079] The invention is not limited to the examples just described; in particular, features of the illustrated examples can be combined in unillustrated variants.

[0080] Other variants and embodiments may be envisaged without departing from the scope of the invention.

Claims

Demands

1. A walking assistance device (100) for a human lower limb (J1), comprising at least: - a proximal element (110) extending along a longitudinal axis (X), - a distal element (120) comprising at least one portion (121) movable relative to the proximal element, - a joint (130) connecting the distal element (120) to the proximal element (110), and comprising at least one cable (131) configured to be tensioned by a translation of the movable portion (121) of the distal element (120) towards the proximal element (110), and the joint (130) being able to assume at least one free mode in which the distal element is rotationally movable relative to the proximal element about an axis of rotation (R) of the joint (130), and one constrained mode in which the proximal element (110) and the distal element (120) are rotationally linked to each other,The tensioning of the cable (131) causes the transition from free mode to constrained mode.

2. Device (100) according to the preceding claim, wherein the distal element (120) is further connected to the proximal element (110) by at least one elastic return means (140) when the joint is in constrained mode, and wherein the joint (130) comprises at least one drum (132) movable about the axis of rotation (R) of the joint (130), the elastic return means (140) comprising at least one hooking means (141) which cooperates with the drum (132).

3. Device (100) according to the preceding claim, the cable (131) being wound around the drum (132), loosely when the joint (130) is in free mode, and the cable (131) being guided at least partially by a guiding means (124) carried by the movable part (121) of the distal element (120).

4. Device (100) according to the preceding claim, the cable (131) constituting an attachment means (141) for the elastic return means (140) which cooperates with the drum (132).

5. Device (100) according to claim 2, comprising a cylinder (133) rotationally linked with the movable part (121) of the distal element (120), the cable (131) being wound around this cylinder (133), loosely when the joint (130) is in free mode.

6. Device (100) according to the preceding claim, two ends (134, 135) of the cable (131) being fixed to the drum (132) and the cable (131) being at least partially guided by a guiding means (124) carried by the movable part (121) of the distal element (120).

7. Device (100) according to the preceding claim, the two ends (134, 135) of the cable (131) being fixed to the drum (132) in a diametrically opposite manner.

8. Device (100) according to claim 5, two ends (134, 135) of the cable (131) being fixed on the movable part (121) of the distal element (120) and the cylinder (133) being rotationally linked with the drum (132).

9. Device (100) according to claim 5, the cylinder (133) being linked in rotation and translation with the movable part (121) of the distal element (120) and two ends (134, 135) of the cable (131) being fixed, in a diametrically opposite manner, to the drum (132).

10. Device (100) according to claim 2, the joint (130) comprising a braking member (151) rotationally linked to the drum (132), and a braking jaw (152) controlled by the tensioning of the cable (131), the braking jaw (152) being configured to grip the braking member (151) when the cable (131) is tensioned.

11. Device (100) according to claim 2, the joint (130) comprising a first clutch element (161) integral with the drum (132) and a second clutch element (162) rotationally linked with the distal element (120), the tensioning of the cable (131) causing a connection of the first clutch element (161) and the second clutch element (162) with each other.

12. Device (100) according to claim 2, comprising a cylinder (133), the cable (131) being loosely wound around the cylinder (133) when the joint (130) is in free mode and the movable part (121) of the distal element (120) protruding from an underside (126) of the distal element (120) when the joint (130) is in free mode.

13. Device (100) according to the preceding claim, wherein the movable part (121) of the distal element (120) is formed by at least one piston (127).

14. Device (100) according to any one of the preceding claims, adapted to be positioned around a human lower limb (Jl) so that the joint (130) is positioned opposite an ankle of that lower limb (Jl).

15. Device (100) according to any one of the preceding claims in combination with claim 2, comprising at least one motorized actuation system (170, 171, 172, 173) adapted to drive the drum (132) in rotation.

16. Method of putting a joint (130) under constraint by an assistance device (100) according to any one of the preceding claims, comprising the steps of: - placing the distal element (120) of the assistance device (100) against a support when the joint (130) is in the free mode, - putting the cable (131) under tension in order to bring the joint (130) into the constrained mode.

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