Shock absorption kit for walking aid crutch

Abstract

The invention relates to a shock-absorbing kit for a kickstand comprising a shock-absorbing sub-assembly intended to be inserted into the upper tube (10) of the kickstand in place of its lower tube and comprising: - a stop block (110) having a bore for a pin (32) of a first locking member (30) of the kickstand to pass through, the pin also passing through an upper pair of holes in the upper tube so as to secure it; - a lower leg made of plastic or composite material (150) having an oblong slot (151) for a pin (202) of a second locking member (200) to pass through, the pin also passing through a lower pair of holes in the upper tube so as to allow the leg to slide axially between two extreme positions, high and low; and - a helical compression spring (120) intended to be arranged between the stop block and the leg. Figure to be published with the abbreviation: Fig. 6

Description

Title of the invention: Shock absorption kit for a walking assistance crutch. Technical field.

[0001] The present invention relates generally to the field of walking aid devices, particularly for medical use. It relates in particular to a cushioning kit for a crutch, as well as a crutch comprising such a cushioning kit. Previous technique

[0002] A crutch is generally defined as a medical device used to support all or part of a patient's body weight.

[0003] Axillary or full-size crutches are mainly known, comprising a double support for the armpit and for the hand, as well as forearm or "English" crutches comprising a double support for the forearm and for the hand.

[0004] Figure 1 represents a conventional forearm crutch 1 conforming to the most common model available commercially for several decades and described in particular by document FR 2 679 441 AL

[0005] In the remainder of this description and by convention, when reference is made to orientation qualifiers such as the terms "superior" or "inferior", these shall be defined in relation to the normal position of use of such a crutch 1 by a user.

[0006] With reference to this [Fig. 1], the support 1 comprises: - a metallic cylindrical upper tube 10 provided with two pairs, upper and lower, axially spaced, of circular holes 11 diametrically opposed to each other; - a lower cylindrical metal tube 20 suitable for being partially inserted by telescopic sliding into said upper tube 10 and also provided with one or more pairs spaced along its axis, of diametrically opposed circular holes facing each other (the latter not being visible on this [Fig.1]); - a first locking member 30 comprising an elastically deformable collar 31 clippable onto said upper tube and an internal radial pin 32 intended to pass through a pair of holes 11 of the upper tube 10 as well as a pair of holes of the lower tube 20 so as to axially lock the position of the latter in order to adjust the height of the support.

[0007] The support 1 also includes a gripping head 40 fixedly fitted (typically by press fitting) onto the upper end of the upper tube 10 and made, for example, from a one-piece molding in plastic material.

[0008] This gripping head 40 conventionally comprises a handle 41 extending in a direction substantially perpendicular to the axis of the upper tube 10, as well as a support for the forearm 42 extending obliquely upwards from this handle 41 and comprising at its upper end a cradle in the shape of an arc of a circle 43 serving as a support for this forearm.

[0009] The stand 1 also includes an anti-slip foot 50, intended to ensure contact with the ground, and mounted by fitting onto the lower end of the lower tube 20.

[0010] Furthermore, and in order to limit friction between the upper metal tubes 10 and lower metal tubes 20 during its use, the stand 1 finally includes a plastic end piece 60 which is press-fitted onto the lower end of the upper tube 10, this end piece 60 being provided with a lower cylindrical collar 61 resting against the lower edge of this upper tube 10 and whose internal diameter is slightly smaller than that of this same tube 10.

[0011] In use, a significant part of the ground impact force of these crutches 1 is transmitted to the upper body of the user and in particular to the most sensitive areas which constitute the joints of the wrist, elbow and shoulder, which can cause inflammatory pain to this user especially when his pathology requires him to use them for a long period.

[0012] In order to limit the transmission of this impact force to the ground to the user, some models of crutches are equipped with an integrated damping device.

[0013] Crutches are known to have an external helical compression spring surrounding their lower tubular part and whose two upper and lower ends are respectively coupled to the upper tube and the lower tube.

[0014] It is understood that the pressure exerted on the upper tube causes a telescopic movement of the lower tube in said upper tube by putting the spring under stress.

[0015] Although providing some attenuation of the impact force transmitted to the user and therefore better user comfort, these crutches generate particularly unpleasant operating noises for the user and pose a risk of pinching the fingers of young children playing near the user.

[0016] In addition, they have a high purchase cost for users, which is generally added to that of a pair of "classic" crutches (i.e. without such shock-absorbing means) previously purchased.

[0017] This cost issue largely explains the poor commercial success of these shock-absorbing crutches.

[0018] In order to improve user comfort while limiting the necessary financial investment, recent years have seen the development of damping kits intended to be installed later in conventional crutches.

[0019] US patent 2007 / 0277865 Al discloses a shock-absorbing kit for a kickstand comprising: - a first stop collar intended to be fixedly mounted around a lower portion of the upper tube; - a second stop collar intended to be fixed around a lower portion of the lower tube; and - an external helical compression spring intended to be positioned between said first stop and said second stop with its two upper and lower ends which are respectively received in corresponding recesses provided in the first and second collars.

[0020] However, simply tightening the stop collars onto the upper and extension tubes creates a significant risk of the collars slipping along these tubes during use of the kickstand, potentially causing the user to fall. Furthermore, the problems related to operating noise and the risk of pinching the fingers of young children near the kickstand user persist.

[0021] US patent 2013 / 0263903 Al discloses another type of kickstand damping kit comprising: - a piston cylinder comprising a stop bottom surface; - a piston rod configured to move axially inside the piston cylinder; and - a damper configured to be located on the piston rod and to butt against the stop surface to reduce the speed of movement of the piston rod inside the piston cylinder.

[0022] This damping kit is configured to be fully installed in a removable manner in an internal space formed collectively by the upper and lower tubes of the kickstand.

[0023] More specifically, the piston cylinder and piston rod are each configured to be fixed respectively to the lower tube and upper tube when the shock absorber insert is removably mounted in the internal space, the shock absorber insert as a whole allowing mutual longitudinal movement between the upper and lower support elements.

[0024] In practice, however, this type of kit does not provide sufficient cushioning of impacts with the ground. Description of the invention

[0025] The present invention therefore aims to improve the situation.

[0026] For this purpose, it proposes a shock-absorbing kit for a walking assistance crutch of the type comprising an upper cylindrical tube having at least two pairs of axially spaced upper and lower opposite holes, a lower cylindrical tube suitable for being partially inserted by telescopic sliding into said upper tube and also having at least one pair of opposite holes, as well as a first locking member having a pin intended to pass through said pair of holes in said upper tube and said pair of holes in said lower tube so as to axially lock the position of the latter.

[0027] The damping kit according to the invention is characterized in that it comprises a second locking member equipped with said pin and a damping sub-assembly intended to be inserted into said upper tube in replacement of said lower tube and comprising: - a stop block having a diametrical hole designed to be passed through by the pin of said first locking member, which also passes through said upper pair of holes so as to ensure its fixing inside said upper tube, - a lower cylindrical leg made of plastic or composite material having an oblong diametrical slot oriented axially and designed to be passed through by the pin of said second locking member, which also passes through said lower pair of holes so that said lower leg can slide axially relative to said upper tube between two extreme positions, high and low, in which this leg protrudes partially from said upper tube, and - a helical compression spring intended to be arranged between said stop block and said lower leg so as to elastically return said lower leg to its extreme upper position.

[0028] With an intuitive and quick assembly, the damping kit according to the invention makes it possible to attenuate the impact force transmitted to the user while considerably limiting the operating noise compared to existing kits due to the plastic or composite material of its lower leg, so as to ensure a much better user comfort.

[0029] Its relatively simple design also ensures a low production cost, making it affordable for everyone. Finally, the arrangement of its spring inside the upper tube prevents any risk of pinching the fingers of young children playing near the user.

[0030] In order to ensure a perfectly smooth and silent sliding of the lower leg relative to the upper tube while limiting its mechanical wear in order to optimize its lifespan, this lower leg will advantageously be made from a self-lubricating thermoplastic polymer resin possibly reinforced with synthetic and / or natural fillers.

[0031] In order to limit the mechanical wear of this lower leg over time and to ensure a lifespan of several years, this self-lubricating thermoplastic polymer resin will preferably be chosen from polyoxymethylene (POM), polyethylene terephthalate (PETP), polyetheretherketone (PEEK) and polytetrafluoroethylene (PTFE).

[0032] In order to keep the longitudinal axis of the spring centered on the longitudinal axis of the upper tube so as to ensure optimal compression of this spring when using the kickstand, said shock absorber sub-assembly advantageously comprises two hollow cylindrical caps, upper and lower, respectively fitted overlapping onto the upper and lower ends of the spring.

[0033] According to a preferred conformation, each of said caps comprises an outer cylindrical envelope covering a respective end portion of the spring, and a circular bottom wall against the inner face of which rests a corresponding end coil of this spring.

[0034] In order to limit friction with the upper tube so as to further reduce operating noise, improve its corrosion resistance and increase its service life, said compression spring is advantageously covered with an anti-friction coating.

[0035] In order to allow better adaptation of the stand equipped with said damping kit according to the invention to the need and / or morphology of the user, the damping sub-assembly preferably includes at least one adjustment element provided to be disposed, prior to the insertion of said lower leg inside said upper tube of the stand, in its oblong opening at the level of one or the other of its ends, so as to limit the sliding stroke of this lower leg.

[0036] According to a preferred conformation, each said adjustment member has a width and depth substantially identical to those of said oblong light, so as to fill by correspondence of shape a portion of the end of the latter.

[0037] In order to ensure its axial retention vis-à-vis said lower leg after its installation, each said adjusting member preferably comprises at one of its transverse ends an interface lug intended to fit into one of the complementary shaped counterbores made on said lower jamb at the periphery of both ends of said light.

[0038] In order to ensure a more advanced level of personalization for the user, the damping kit according to the invention may advantageously include several said interchangeable adjustment elements of different lengths.

[0039] In order to increase the restoring force exerted by said spring so as to make the behavior of the kickstand firmer and therefore better suited to users of heavy build, said shock absorber sub-assembly preferably includes at least one cylindrical preload shim intended to be inserted entirely inside said upper tube, either between said stop block and said spring, or between said spring and said lower leg.

[0040] In order to ensure a more advanced level of personalization for the user, the damping kit according to the invention may advantageously include several interchangeable preload shims of different lengths.

[0041] Still with the aim of limiting the operating noise of the stand equipped with the damping kit according to the invention, caused in particular by the repeated friction exerted during the relative sliding between said damping sub-assembly and said upper tube of this stand, all the constituent elements of said damping sub-assembly with the exception of said spring are advantageously made of plastic or composite material.

[0042] Furthermore, and in order to facilitate the placement of said stop block inside said upper tube of the stand so that its diametrical drilling is aligned with the upper pair of holes of this tube to allow the insertion of the pin of said first locking member, the constituent elements of said shock absorber sub-assembly are suitable for being removably fixed to each other by means of snap-fit ​​fixing means.

[0043] The invention further relates, in a second aspect, to a walking assistance crutch comprising an upper cylindrical tube provided with at least two pairs, upper and lower, axially spaced, of opposite holes, a first locking member having a pin, as well as such a damping kit of which said damping sub-assembly is inserted in said upper tube, the pin of said first locking member passing through said stop block and said upper pair of holes so as to ensure its fixing inside said upper tube, the pin of said second locking member passing through said lower cylindrical leg and said lower pair of holes so as to allow said lower leg to slide axially vis-à-vis said upper tube between said extreme upper and lower positions. Brief description of the drawings

[0044] The description of the invention will now be continued by a detailed description of several embodiments, given below by way of illustration but not limitation, with reference to the accompanying drawings, on which: - [Fig.l] represents a perspective view of an English-type walking aid crutch conforming to the model most commonly found in commerce and including a first clip-on ring with pin allowing the positioning of the lower tube to be locked; - [Fig.2] is a perspective view of an assembly consisting of a conventional kickstand such as that of [Fig.1] and a damping kit according to the invention including in particular a damping sub-assembly inserted in the upper tube of this kickstand in place of its lower tube; - [Fig.3] represents a perspective view showing the shock absorber sub-assembly in assembled configuration preparing to be inserted into the upper tube of the kickstand; - [Fig.4] and [Fig.5] are exploded perspective views from different angles of the damping kit according to the invention; - [Fig.6] and [Fig.7] represent diametrical longitudinal cross-sectional views of the lower part of the entire [Fig.2] assembly, respectively in its resting configuration and in its fully retracted configuration; and - [Fig. 8] is a perspective view of the upper cap that comprises the shock absorber subassembly; and - [Fig.9] represents an exploded view of a preferred embodiment of the lower cap included in the shock absorber subassembly. Description of the implementation methods

[0045] Fig. 2 represents a perspective view of an assembly consisting of a classic English-type crutch 1 as described previously in support of Fig. 1 but with its lower tube 20 removed, and a damping kit K according to the invention mounted on the upper tube 10 of this crutch 1.

[0046] As can be seen in [Fig.3], the damping kit K according to the invention consists of a damping sub-assembly 100 intended to be introduced into the upper tube 10 in replacement of the lower tube 20, and a second locking member 200 comprising an elastically deformable collar 201 clippable onto the upper tube 10 and an internal radial pin 202 similar to that 32 of the first locking member 30.

[0047] We will now describe in detail the different constituent elements of the shock absorber sub-assembly 100.

[0048] This shock absorber sub-assembly 100 includes a cylindrical stop block 110 intended to be inserted entirely first inside the upper tube 10 and to be fixed there by means of the first locking member 30 that comprises the stand 1.

[0049] This stop block 110 thus has a diametrical through bore of cylindrical shape 111 whose diameter is slightly greater than that of the pin 32 of this first locking member 30.

[0050] As can be seen in figures 6 and 7, this hole 111 is intended to be passed transversely by this pin 32 which also passes through the upper pair of holes 11 of the upper tube 10 of the stand 1, so as to ensure the fixing of this stop block 110 inside this upper tube 10.

[0051] The shock absorber sub-assembly 100 also includes a helical compression spring 120 intended to be inserted entirely inside the upper tube 10 after the stop block 110.

[0052] According to an advantageous feature of the invention and as can be seen in figures 3 and 4, this shock absorber sub-assembly 100 further comprises two hollow cylindrical caps, upper 130 and lower 140, respectively fitted overlapping onto the upper and lower ends of the spring 120.

[0053] Each of these caps 130, 140 comprises an outer cylindrical envelope 131, 141 covering a respective end portion of the spring 120, and a circular bottom wall 132, 142 against the inner face of which rests a corresponding end coil of this spring 120.

[0054] The presence of these caps 130, 140 makes it possible in particular to keep the longitudinal axis of the spring 120 centered on the longitudinal axis of the upper tube 10 of the stand 1 so as to guarantee optimal compression of this spring 120 when using this stand.

[0055] These caps 130, 140 also prevent any direct contact between the ends of this spring 120 and the inner face of the upper metal tube 10 of the stand 1, which limits the transmission of vibrations generated by this spring 120 to the user's arm via this upper tube 10 and reduces unwanted noise.

[0056] In order to increase the contact area between the inner faces of the bottom walls 132, 142 of these caps 130, 140 and the end coils of the spring 120 so as to improve its stability, the latter are advantageously closed and ground.

[0057] In order to limit friction, in particular with the upper tube 10, so as to further reduce operating noise, improve its resistance to corrosion and increase its lifespan, this compression spring 120 can also be covered with an anti-friction coating, for example in polymer resin.

[0058] Other surface treatments such as shot blasting, passivation or chrome plating can also be applied to this compression spring 120 in order to further improve its lifespan and / or resistance to corrosion.

[0059] In order to ensure sufficient cushioning for users of heavy build, its stiffness will advantageously be between 2 and 4 N / mm.

[0060] The shock absorber sub-assembly 100 further comprises a lower cylindrical leg 150 made of plastic or composite material, intended to be partially inserted inside the upper tube 10 of the stand after the spring 120, and on the lower end of which the anti-slip foot 50 of this stand 1 is fitted as illustrated by figures 2, 6 and 7.

[0061] This lower cylindrical jamb 150 has, in its upper part, an oblong diametrical light 151 oriented axially and whose width is slightly greater than the diameter of the pin 202 of the second locking member 200.

[0062] As can be seen in figures 6 and 7, this oblong opening 151 is intended to be crossed transversely by this pin 202 which also passes through the lower pair of holes 11 provided on the upper tube 10 of the support 1, so that this leg 150 can slide axially vis-à-vis the upper tube 10 between two extreme positions high and low in which it protrudes partially out of this upper tube 10.

[0063] The external diameter of the lower leg 150 will advantageously be defined so that the gap with the internal diameter of the lower collar 61 of the end fitting 60 fitted onto the lower end of the upper tube 10 is less than 0.3 millimeters and preferably between 0.1 and 0.2 millimeters.

[0064] This small gap limits the transverse movement of the lower leg 150 during its axial sliding inside the upper tube 10, thus ensuring greater user comfort. It also limits air leakage between this lower leg 150 and this collar 61, thereby providing additional cushioning to that provided by the spring 120 during violent impacts with the ground (for example, in the event of a loss of balance by the user combined with a sudden recovery movement).

[0065] Still with the aim of ensuring additional damping to that exerted by the spring 120, it will be noted that the external diameter of the stop pad 110 will also be advantageously defined so that the gap with the internal diameter of the upper tube 10 is less than 0.3 millimeter and preferably between 0.1 and 0.2 millimeter, in order to limit the air leakage between this stop pad 110 and this upper tube 10.

[0066] In order to adapt to the size of the user, the damping kit according to the invention may advantageously comprise several interchangeable lower legs of different lengths.

[0067] Configured to elastically return this lower leg 150 to its lowest extreme position, the spring 120 will advantageously have sufficient length so that it remains partially compressed when this lower leg 150 reaches this lowest extreme position corresponding to the resting configuration of the kickstand 1 equipped with the kit according to the invention (see [Fig. 6]). This residual compression of the spring 120 makes it possible to exert a minimum restoring force on the lower leg 150, ensuring secure support for the user upon contact with the ground as well as faster absorption of the impact force.

[0068] In order to allow better adaptation of the stand 1 equipped with the damping kit K to the need and / or morphology of the user, the damping sub-assembly 100 preferably includes at least one adjustment member 160 intended to be disposed, prior to the insertion of the lower leg 150 into the upper tube 10 of the stand, in its oblong slot 151 at the level of one or the other of its ends, so as to limit the sliding stroke of this lower leg 150 as illustrated by [Fig.7].

[0069] Depending on its position at the upper or lower end of the oblong light 151 of the lower leg 150, the addition of such an adjustment element 160 will thus allow the height of the support to be adjusted in its rest configuration or in its fully retracted configuration.

[0070] It will also be noted that the arrangement of such an adjustment element 160 at the lower end of this oblong opening 151 will limit the compression stroke of the spring 120 and thus increase its lifespan and limit operating noise.

[0071] As illustrated by figures 4 and 5, each adjustment member 160 advantageously has a width and depth substantially identical to those of the oblong opening 151, so as to fill by correspondence of shape an end portion of the latter.

[0072] In order to ensure its axial retention vis-à-vis the lower jamb 150 after its installation, each adjustment member 160 preferentially includes at one of its transverse ends an interface lug 161 intended to fit into one of the counterbores of complementary shape 152 provided on this lower jamb 150 at the periphery of the two ends of the light 151.

[0073] The damping kit K according to the invention may advantageously include several interchangeable adjustment elements 160 of different lengths so as to ensure a more advanced level of customization for the user.

[0074] In order to allow for better adaptation of the kickstand equipped with the damping kit K to the user's needs and / or morphology, the shock absorber sub-assembly 100 may also include at least one cylindrical shim of prestress 170 intended to be introduced entirely inside the upper tube 10 of the stand 1, either between the stop block 110 and the spring 120, or between this spring 120 and the lower leg 150 as illustrated by figures 3 to 7, so as to increase the residual compression of the spring 120 in the rest configuration of the stand 1 equipped with the kit according to the invention.

[0075] This increase in the residual compression of the spring 120 will thus increase the restoring force exerted by this spring 120 so as to make the behavior of the kickstand firmer and therefore better suited to users of heavy build.

[0076] The damping kit K according to the invention may advantageously include several interchangeable preload shims 170 of different lengths so as to ensure a more advanced level of customization for the user.

[0077] In order to further limit the operating noise of the stand 1 caused in particular by the repeated friction exerted during the relative sliding between the shock absorber sub-assembly 100 and the upper tube 10 of this stand 1 during its use, all the constituent elements of this shock absorber sub-assembly 100, with the notable exception of the spring 120, shall advantageously be made of plastic or composite material.

[0078] In order to ensure perfectly smooth and silent sliding of the lower leg 150 vis-à-vis the upper tube 10 while limiting its mechanical wear in order to optimize its lifespan, the lower leg 150 will advantageously be made from a self-lubricating thermoplastic polymer resin possibly reinforced with synthetic and / or natural fillers.

[0079] In order to limit the mechanical wear of this lower jamb 150 over time and to ensure its lifespan of several years, this self-lubricating thermoplastic polymer resin will preferably be chosen from polyoxymethylene (POM), polyethylene terephthalate (PETP), polyetheretherketone (PEEK) and polytetrafluoroethylene (PTFE).

[0080] In order to reduce production costs in the case of limited production volumes, the lower jamb 150 will advantageously be obtained by machining from a solid rod of standard diameter. In the case of larger production volumes, this lower jamb 150 could be obtained directly by a plastic injection molding process.

[0081] Apart from this lower leg 150, the other plastic or composite elements constituting the shock absorber sub-assembly 100 (namely, the stop block 110, the caps 130, 140, the adjustment member(s) 160 and the preload shim(s) 170) will advantageously be obtained by a process three-dimensional printing, from a thermoplastic polymer resin possibly reinforced with synthetic and / or natural fillers.

[0082] The three-dimensional printing process used will be, for example, of the type by fused filament deposition (or FDM for "Fused Deposition Modeling" in English), by stereolithography (or SLA for "Stereolithography" in English), or by selective laser sintering (or SLS for "Selective Laser Sintering" in English).

[0083] In the case of larger production volumes, these elements could alternatively be produced by a plastic injection process.

[0084] In order to limit the mechanical wear of these parts over time and to ensure their lifespan of several years, this thermoplastic polymer resin will preferably be chosen from glycolized polyethylene terephthalate (PETG), polylactic acid (PLA), acrylonitrile butadiene styrene (ABS), polyamide (PA), acrylonitrile styrene acrylate (ASA) and polycarbonate (PC).

[0085] Furthermore, and in order to facilitate the placement of the stop block 110 inside the upper tube 10 of the stand 1 so that its diametrical hole 111 is aligned with the upper pair of holes 11 of this tube 10 to allow the insertion of the pin 32 of the first locking member 30, the constituent elements of the shock absorber sub-assembly 100 are suitable for being removably fixed to each other by means of snap-fit ​​fixing means.

[0086] To ensure the attachment of the ends of the spring 120 to the caps 130 and 140, these snap-fit ​​attachment means comprise, on each cap 130, 140 and as can be seen in [Fig.8] with reference to the upper cap 130, an inner annular ring 133 projecting from its bottom wall 132 centered on its axis and intended to allow the press-fitting of a corresponding end coil of the spring 120.

[0087] To ensure the fixing between two successive plastic or composite elements of this shock-absorbing sub-assembly 100 and as can be seen in figures 4 and 5, these fixing means include a pin P projecting from one of the ends of the first element (such a pin P projecting in this case from the lower ends of the stop block 110, the lower cap 140 and the pre-stressing wedge 170) and intended to fit by force into a recess E of complementary shape formed on the corresponding end opposite the second element (such a recess E being formed in this case on the upper ends of the upper cap 130, the pre-stressing wedge 170 and the lower leg 150).

[0088] For ease of manufacturing by three-dimensional printing, it will be noted in support of [Fig. 9] that the lower cap 140 is advantageously made up of two separate parts assembled to each other by interlocking. force, namely a first part 140A identical to the upper cap 130 and a second part 140B; the latter comprising a cylindrical base 140Ba intended to fit forcefully into the inner housing defined by the inner annular ring of the first part 140A, as well as a cylindrical finger 140Bb passing through the through imprint E made in the bottom wall of this first part 140 and forming the pin P of this lower cap 140.

[0089] Numerous other embodiments are also possible, and it should be noted in this regard that the invention is not limited to the embodiments described and illustrated, but also encompasses all embodiments within the grasp of a person skilled in the art. In particular, it should be specified that the damping kit K according to the invention can also be mounted on crutches of different types, such as axillary or full-size crutches, provided that their configuration is compatible with the installation of such a kit.

Claims

Demands

1. Damping kit (K) for a walking assistance crutch (1) of the type comprising an upper cylindrical tube (10) having at least two pairs of axially spaced upper and lower opposite holes (11), a lower cylindrical tube (20) capable of being partially inserted by telescopic sliding into said upper tube (10) and also having at least one pair of opposite holes,as well as a first locking member (30) having a pin (32) intended to pass through said pair of holes (11) of said upper tube (10) and said pair of holes of said lower tube (20) so as to axially lock the position of the latter; characterized in that said damping kit (K) comprises a second locking member (200) having said pin (202) as well as a damping sub-assembly (100) intended to be inserted into said upper tube (10) in replacement of said lower tube (20) and comprising: - a stop block (110) having a diametrical hole (111) intended to be passed through said pin (32) of said first locking member (30) also passing through said upper pair of holes (11) so as to ensure its fixing inside said upper tube (10),- a lower cylindrical leg made of plastic or composite material (150) having an oblong diametrical slot (151) oriented axially and provided for passage by the pin (202) of said second locking member (200), which also passes through said lower pair of holes (11) so that said lower leg (150) can slide axially relative to said upper tube (10) between two extreme high and low positions in which said leg (150) protrudes partially out of said upper tube (10), and - a helical compression spring (120) intended to be arranged between said stop block (110) and said lower leg (150) so as to elastically return said lower leg (150) to its extreme low position.

2. Damping kit (K) according to claim 1, characterized in that said lower leg (150) is made from a self-lubricating thermoplastic polymer resin optionally reinforced with synthetic and / or natural fillers.

3. Damping kit (K) according to claim 2, characterized in that said self-lubricating thermoplastic polymer resin is selected from polyoxymethylene (POM), polyethylene terephthalate (PETP), polyetheretherketone (PEEK) and polytetrafluoroethylene (PTFE).

4. Damping kit (K) according to any one of claims 1 to 3, characterized in that said damper subassembly (100) comprises two upper (130) and lower (140) hollow cylindrical caps respectively fitted overlapping onto the upper and lower ends of said spring (120).

5. Damping kit (K) according to claim 4, characterized in that each said cap (130, 140) comprises a cylindrical outer casing (131, 141) covering a respective end portion of said spring (120), and a circular bottom wall (132, 142) against the inner face of which rests a corresponding end coil of said spring (120).

6. Damping kit (K) according to any one of claims 1 to 5, characterized in that said compression spring (120) is covered with an anti-friction coating.

7. Damping kit (K) according to any one of claims 1 to 6, characterized in that the damper subassembly (100) comprises at least one adjustment member (160) provided to be disposed, prior to the insertion of said lower leg (150) into said upper tube (10) of the stand, in its oblong opening (151) at one or the other of its ends, so as to limit the sliding stroke of this lower leg (150).

8. Damping kit (K) according to claim 7, characterized in that each said adjusting member (160) has a width and depth substantially identical to those of said oblong opening (151), so as to fill by matching shape an end portion of the latter.

9. Damping kit (K) according to any one of claims 7 or 8, characterized in that each said adjustment member (160) comprises at one of its transverse ends an interface lug (161) intended to fit into one of the complementary shaped counterbores (152) provided on said lower jamb (150) at the periphery of both ends of said light (151).

10. Damping kit (K) according to any one of claims 7 to 9, characterized in that it comprises several said interchangeable adjustment members (160) of different lengths.

11. Damping kit (K) according to any one of claims 1 to 10, characterized in that said damper subassembly (100) comprises at least one cylindrical preload shim (170) intended to be inserted entirely inside said upper tube (10), either between said stop block (110) and said spring (120), or between said spring (120) and said lower leg (150).

12. Damping kit (K) according to claim 11, characterized in that it comprises several said interchangeable preload shims (170) of different lengths.

13. Damping kit (K) according to any one of claims 1 to 12, characterized in that all the constituent elements of said damping subassembly (100) except said spring (120) are made of plastic or composite material.

14. Damping kit (K) according to any one of claims 1 to 13, characterized in that the constituent elements of said damping subassembly (100) are capable of being removably fixed to one another by means of snap-fit ​​fastening means.

15. A walking aid crutch comprising an upper cylindrical tube (10) having at least two axially spaced upper and lower pairs of opposite holes (11), a first locking member (30) having a pin (32), and a damping kit (K) according to any one of claims 1 to 14, wherein said damping subassembly (100) is inserted into said upper tube (10), the pin (32) of said first locking member (30) passing through said stop block (110) and said upper pair of holes (11) so as to secure it inside said upper tube (10), the pin (202) of said second locking member (200) passing through said lower cylindrical leg (150) and said lower pair of holes (11) so as to allow said lower leg (150) to slide axially relative to said tube superior (10) between said extreme high and low positions.

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