Wheelchair for the disabled with a multi-position seat controlled by a single cylinder

Description

Technical Field

[0001] The present invention relates to the technical field of wheelchairs for disabled people or those with reduced mobility, which comprise a mechanism for moving the user's seat structure. Prior art

[0002] Generally speaking, a wheelchair comprises a supporting frame equipped with wheels and supporting a seating structure for the person, including in particular a footrest, a seat and a backrest. To allow the user to change their position relative to the frame, the wheelchair is provided with a mechanism adapted to move the seating structure. The state of the art has proposed numerous solutions for producing the mechanism for moving the seating structure, depending on the movements possible for the user. From the state of the prior art, documents US 2019 / 125599 and US 2016 / 101664 are known, which describe systems for moving a wheelchair seating structure.

[0003] To allow a modification of the height of the seat structure, application WO 92 / 15271, for example, proposed an armchair comprising a supporting frame and lifting means, interposed between the frame and the seat structure.

[0004] To modify the general inclination or position of the seat structure, patent EP2004124 proposes to improve a lift chair, by allowing the seat structure to adopt a backward inclined position. Such a solution allows in particular relaxation of the user while reducing the pressure on the ischial bones and the buttocks to reduce the risk of the appearance of pressure sores and the shearing effects due to changes in position.

[0005] It also appears necessary for the seat structure to be positioned at the front of the chair to facilitate access to the chair or the transfer of the user. However, the positioning of the seat structure in relation to the chassis must of course take into account the safety of the user and the constraints linked to the proper functioning of the chair. It thus appears that the user's center of gravity must remain within the support polygon of the chair both in terms of safety but also to ensure a balanced distribution of the loads on the wheels of the chair.

[0006] In order to keep the person's center of gravity in the center of the chair as much as possible, it also appears necessary for the seat to be able to move backwards on descents and forwards on ascents.

[0007] In order to tackle steep slopes, the person sitting in the chair also needs to maintain a flat position regardless of the slope to be descended.

[0008] It therefore appears that a wheelchair must have a first function of moving the seat structure in the longitudinal front-rear direction and a second function of tilting the seat structure. The implementation of each function requires the use of a displacement cylinder. However, the space available between the supporting frame and the seat structure is generally limited, not allowing the installation of two displacement cylinders. The use of a single cylinder appears a priori to be irrelevant for sliding and tilting the seat structure.

[0009] The analysis of the state of the art leads to the conclusion that there is a need for a wheelchair of simple design, suitable for positioning the seat structure in various positions depending on the conditions of use of the wheelchair. Statement of the invention

[0010] The object of the invention is to satisfy this need by proposing a wheelchair for a disabled person or person with reduced mobility, of simple design, adapted to move using a single cylinder, by sliding and tilting the seat structure in order to position it in different positions and in particular, in a forward position, in a central safety position and in a tilted position.

[0011] To achieve such an objective, the subject of the invention relates to a wheelchair for a disabled person or person with reduced mobility comprising: a supporting frame, a seating structure for the person comprising at least one seat and a backrest, a mechanism for moving the seating structure interposed between the frame and the seating structure, the moving mechanism comprising: * a system for guiding the seating structure horizontally in the front-to-back direction of the chair, * a deformable structure interposed between the horizontal sliding guiding system and the seating structure, this deformable structure comprising a hinge pin on which acts a motorized jack mounted on the supporting frame in order to move and deploy or fold the deformable structure, * a mechanism for lifting the hinge pin of the deformable structure relative to the supporting frame during the sliding movement in the front-to-back direction of the seating structure,and a cylinder control unit adapted to control the cylinder: * in extension to ensure the sliding of the seat structure to a forward position, * in nominal sliding retraction to ensure the sliding of the seat structure to a nominal safety position, upstream of the lifting mechanism, * in retraction of retraction to ensure the sliding of the seat structure to a retracted position and during which the lifting mechanism acts to lift the articulation axis to initiate the deployment of the deformable structure, * in tilting retraction to deploy the deformable structure so as to position the seat structure in a tilted position relative to the supporting frame.

[0012] The armchair according to the invention has the advantage of being able to move the seat structure using a single jack, sliding and tilting so that it occupies several positions.

[0013] According to an exemplary implementation, the cylinder control unit is adapted to control the cylinder in tilting extension to fold the deformable structure so as to position the seating structure in a non-tilted position relative to the supporting frame.

[0014] According to an advantageous variant, the deformable structure comprises at least one quadrilateral formed of a first branch and a second branch articulated together around the articulation axis, the first branch being linked by a second articulation point to a slide of the horizontal sliding guidance system while the second branch is linked by a third articulation point to the seat structure, the slide being linked to the seat structure by a fourth articulation point. The implementation of such a quadrilateral forming a scissor makes it possible to increase tenfold the forces of the jack acting on the quadrilateral.

[0015] According to an exemplary embodiment, the slider comprises a front part linked by the second articulation point to the first branch and a rear part fixed to the seat of the seating structure by the fourth articulation point.

[0016] Advantageously, the horizontal sliding guidance system comprises a guide comprising a front part fixed to the supporting frame to constantly guide the front part of the slide and to guide the rear part of the slide in the forward position and nominal safety position, the guide comprising a rear part fixed to the seat of the seating structure to receive the rear part of the slide to allow the tilting of the seating structure.

[0017] For example, the horizontal sliding guidance system has an extension stop so that in the forward position, the seat structure protrudes at the front of the supporting frame by a measurement of between 10 cm and 30 cm.

[0018] Advantageously, the horizontal sliding guide system includes a retraction stop allowing the seat structure to be positioned in its retracted position.

[0019] To enable the motorized cylinder to deploy the deformable structure, the hinge axis of the deformable structure is raised relative to the supporting frame in order to initiate the opening of the deformable structure. According to a preferred embodiment, the mechanism for raising the hinge axis of the deformable structure relative to the supporting frame comprises at least one ramp fixed to the supporting frame with which the deformable structure cooperates during the sliding movement of the seat structure to initiate the deployment of the deformable structure.

[0020] Indeed, without the presence of the ramp, the backward movement of the jack to obtain the tilting of the seat structure is just physically impossible since, due to lack of available space, the jack works parallel to the seat of the seat structure. The jack cannot therefore tilt the seat structure, due to the angle of application of the force, which is at 0°. To have force, the jack should instead work perpendicular to the desired position. The ramp therefore allows the angle of application of the jack's force to be modified to be different from 0°. However, the angle obtained at the end of the ramp remaining too small, the invention implements below the seat, a deformable structure with a chisel in order to multiply the traction force.

[0021] For example, the ramp cooperates with a roller carried by the first branch of the quadrilateral connected to the slide. Brief description of the drawings

[0022] [Fig. 1 ] There figure 1 is a ¾ front view of a wheelchair according to the invention “in the nominal safety position”. [ Fig. 2 ] There figure 2 is a side view of a wheelchair according to the invention “in the nominal safety position”. [ Fig. 3 ] There figure 3 is a perspective view of the mechanism for moving the seat structure of a wheelchair according to the invention “in the nominal safety position”. [ Fig. 4 ] There figure 4 is a side view of a wheelchair according to the invention, showing the seat structure “in the forward position”. [ Fig. 5 ] There figure 5 is a perspective view of the mechanism for moving the seat structure “in the forward position”. [ Fig. 6 ] There figure 6 is a side view of a wheelchair according to the invention, showing the seat structure “in the retracted position”. [ Fig. 7 ] There figure 7 is a perspective view of the mechanism for moving the seat structure "in the retracted position". [ Fig. 8 ] There figure 8 is a side view of the lifting mechanism in the initial position, forming part of the mechanism for moving the seating structure. Fig. 9 ] There figure 9 is a side view of the lifting mechanism in the intermediate position, forming part of the mechanism for moving the seat structure. Fig. 10 ] There figure 10 is a side view of the lifting mechanism in the final position, forming part of the mechanism for moving the seat structure. Fig. 11 ] There figure 11 is a ¾ front view of a wheelchair according to the invention, showing the seat structure “in the tilted position”. [ Fig. 12 ] There figure 12 is a side view of a wheelchair according to the invention, showing the seat structure “in the tilted position”. [ Fig. 13 ] There figure 13 is a perspective view of the mechanism for moving the seat structure "in the tilted position". [ Fig. 14 ] There figure 14 is a side view of the horizontal sliding guidance system of the seat structure, “in the nominal safety position”. [ Fig. 15 ] There figure 15 is a side view of the horizontal sliding guidance system of the seat structure, in an “advanced position”. Fig. 16 ] There figure 16 is a side view of the horizontal sliding guidance system of the seat structure, “in the tilted position”. Description of the embodiments

[0023] As can be seen from the figures, the subject of the invention relates to a wheelchair 1 for a disabled person or person with reduced mobility. The wheelchair 1 comprises a supporting frame 2 on which a seating structure 3 for a person is fitted. In the embodiment illustrated in the drawings, the supporting frame 2 is equipped with two front wheels 4 and two rear wheels 5. The wheels 4, 5 define, by the points of contact with the ground, a support or lift polygon in which the mass or load represented by the seating structure 3 is positioned.

[0024] For example, the wheelchair 1 is a motorized wheelchair with drive wheels driven in rotation by a motorization of any type known per se, powered by a set of batteries. The wheels are controlled in rotation and are steerable using a control unit 6 of any type known per se, comprising for example a joystick allowing in particular to move forward, backward, turn left or right, the wheelchair according to the invention. It must be considered that the propulsion mode of the wheelchair 1 can be of any type and will not be described in more detail because it is not precisely part of the subject of the invention and is well known to those skilled in the art.

[0025] Conventionally, the seat structure 3 comprises a footrest 3a, a seat 3b and a backrest 3c. Preferably, but not strictly necessary for producing an armchair according to the invention, the seat structure 3 is articulated so as to allow a modification of the relative inclination of the backrest 3c relative to the seat 3b and / or a modification of the relative inclination of the footrest 3a relative to the seat 3b.

[0026] For example, the seat structure 3 also comprises armrests 3d composed of fixed segments 3e rising from the seat structure 3 on either side of the seat 3b and at the end of each of which is articulated a support segment 3f for a forearm. The support segments 3f can thus be raised to position themselves in the extension of the fixed segments 3e to facilitate the transfer of the person ( figure 4 ) as will be described in the remainder of the description.

[0027] The wheelchair 1 comprises a mechanism 8 for moving the seat structure 3, interposed between the supporting frame 2 and the seat structure 3. The wheelchair 1 according to the invention has the particularity of being able to position, thanks to the movement mechanism 8, the seat structure 3 in four characteristic positions.

[0028] The first position called "advanced position" illustrated by the figures 4 , 5 And 15 corresponds to the positioning of the seating structure 3 at the front of the supporting frame 2. For example, in the forward position, the seating structure 3 protrudes at the front of the supporting frame 2, by a measure of between 10 cm and 30 cm. This forward position facilitates access to the seating structure and the transfer of the person. This forward position can also be used when moving the wheelchair uphill.

[0029] The second position called “nominal safety position” illustrated by the figures 1 à 3 and 14 corresponds to the positioning of the seating structure 3 in a neutral position relative to the supporting chassis 2. Depending on the leg length of the person, the seating structure 3 is moved back relative to its forward position, so that the person's center of gravity is located in the central part of the support or lift polygon. This nominal position makes it possible to keep the person safe while balancing the masses on the wheels, limiting wear on the front wheels 4.

[0030] The third position called "backward position" illustrated by the figures 6 And 7corresponds to the positioning of the seating structure 3 in a position set back from the nominal safety position to initiate the tilting of the seating structure 3. For example, the seating structure 3 is moved back 4 cm to move from its initial safety position to its set back position. In this set back position, the tilting of the seating structure 3 has begun.

[0031] The fourth position called "tilted position" illustrated by the figures 11 à 13 and 16 corresponds to the positioning of the seat structure 3 in a tilted position relative to the supporting frame 2. The seat 3b of the seat structure is raised to obtain a tilted position for the person, for example 45° backward. This tilted position allows the user to relax. A tilted position can also be sought so that the seat occupies a horizontal position when the chair moves forward, particularly when going downhill.

[0032] The movement mechanism 8 comprises a guide system 10 for horizontally sliding the seat structure 3 in the front-to-back direction of the chair. The guide system 10 ensures the horizontal sliding guidance of the seat structure 3 when the latter passes from one to the other of its first three positions, namely the forward position, the nominal safety position and the retracted position. In the illustrated embodiment, the guide system 10 comprises at least one fixed guide or slide 11 and in the illustrated example, two guides or slides 11 fixed on either side of the longitudinal edges of the supporting frame 2. Thus, the two guides 11 extend parallel and symmetrically with respect to the longitudinal plane of symmetry of the chair delimiting the front-to-back direction of the chair. Each guide 11 serves to guide in translation a slide 12 supporting the seat structure 3.The seat structure 3 is thus equipped at its base with two sliders 12 extending on either side of the seat 3b.

[0033] According to the preferred embodiment illustrated in the drawings and in particular by the figures 14 à 16 , each guide 11 is made in two separate parts, namely a front part 11a fixed to the supporting frame 2 and a rear part 11b fixed to the seat 3b of the seating structure 3. Similarly, each slider 12 is made in two separate parts, namely a front part 12a forming a sliding connection with the front part 11a of the guide and a rear part 12b forming a sliding connection with the rear part 11b of the guide but also with the front part 11a of the guide, outside the tilted position.In other words, the front part 12a of the slide is constantly guided by the front part 11a of the guide while the rear part 12b of the slide is engaged depending on the position of the seat structure, either only in the rear part 11b of the guide to allow the tilting of the seat structure 3 or also in the front part 11a of the guide, in particular in the advanced position and in the nominal safety position, to lock the two parts of the guide and the slide together, as will be explained in the rest of the description.

[0034] The horizontal sliding guidance system 10 comprises an extension stop 14 corresponding to the advanced position of the seat structure 3. Thus, during its forward sliding movement, the slider 12 comes into contact with the stop 14 to define the extreme advanced position of the seat structure 3. For example, the stop 14 is positioned so that in the advanced position, the seat structure 3 protrudes at the front of the supporting frame 2, by a measurement of between 10 cm and 30 cm.

[0035] Likewise, the horizontal sliding guidance system 10 comprises a recoil stop 15 for positioning the seat structure 3 in its recoiled position. Thus, during its rearward sliding movement, the slider 12 comes into contact with the recoil stop 15 to define the extreme recoiled position of the seat structure 3.

[0036] According to another characteristic of the invention, the movement mechanism 8 comprises a deformable structure 16 interposed between the horizontal sliding guide system 10 and the seat structure 3. This deformable structure 16 comprises a hinge axis 17 on which acts a motorized telescopic jack 18 mounted on the supporting frame 2 in order to move and deploy or fold the deformable structure 16. The jack 18 is preferably mounted in the longitudinal plane of symmetry of the chair and comprises a body 18a fixed to the supporting frame 2 according to an articulation 18b extending perpendicular to the longitudinal plane of symmetry of the chair. The jack 18 comprises a rod 18c connected at its free end by a ball joint, to the hinge axis 17.The cylinder 18 is controlled by the control unit 6 to control the cylinder in extension or retraction so that the seat structure 3 can occupy its four characteristic positions, as will be described in detail in the remainder of the description. The cylinder 18 is made in any suitable manner such as for example an electric cylinder, a hydraulic cylinder, a servomotor or any other suitable means. The cylinder 18 is mounted to be positioned between the upper surface of the supporting frame 2 and the seat structure 3.

[0037] According to a preferred embodiment, the deformable structure 16 comprises at least one deformable quadrilateral 19 and in the example illustrated two deformable quadrilaterals 19 extending on either side of the longitudinal edges of the supporting frame 2. Thus, the two deformable quadrilaterals 19 extend parallel and symmetrically with respect to the longitudinal plane of symmetry of the chair delimiting the front to rear direction of the chair. As is apparent from the figures, the two quadrilaterals 19 are connected to each other by the articulation axis 17 extending transversely with respect to the longitudinal plane of symmetry of the chair.

[0038] Each quadrilateral 19 is formed by a first branch 20 and a second branch 21 articulated together around the articulation axis 17 to form a scissor. The first branch 20 is connected at its end opposite that connected to the articulation axis 17, by a second articulation point 23, to the front part 12a of the slide 12 forming the third side of the quadrilateral. The second branch 21 is connected at its end opposite that connected to the articulation axis 17, by a third articulation point 24, to the seat structure 3 forming the fourth side of the quadrilateral. More precisely, the second branch 21 is connected by the third articulation point 24 to the seat 3b of the seat structure 3. The slider 12 and more precisely its rear part 12b is connected to the seat structure 3 by a fourth articulation point 25 forming the pivoting or tilting axis of the seat structure 3.More precisely, the rear part 12b of the slider 12 is connected to the seat 3b of the seat structure 3, by the fourth articulation point 25 located in the junction region between the seat 3b and the backrest 3c. The quadrilaterals 19 can thus be deployed or folded under the action of the cylinder 18 on the articulation axis 17. The control of the cylinder 18 in retraction leads to the deployment or opening of the quadrilaterals 19 causing the tilting of the seat structure 3. Conversely, the control of the cylinder 18 in extension leads to the folding or closing of the quadrilaterals 19 causing the return of the seat structure 3 to its horizontal position. It should be noted that the implementation of the branches 20, 21 forming scissors increases tenfold the force of the cylinder 18 making it possible to limit the dimensioning of the cylinder.

[0039] It should be noted that in the tilted position of the seat structure 3, the rear part 12b of the slider is engaged only in the rear part 11b of the guide 11, thus allowing the seat structure 3 to tilt. In this tilted position, the front part 12a of the slider is engaged in the front part 11a of the guide 11.

[0040] The cylinder 18 also ensures the horizontal sliding of the seat structure 3 in the front-to-back direction of the chair. The extension control of the cylinder 18 leads to moving the seat structure 3 forward with the sliding of the slider 12 forward, in particular causing the rear part 12b of the slider to engage in the front part 11a of the guide 11. It should be noted that the part 12a of the slider is always engaged in the front part 11a of the guide 11. Thus, in the nominal safety position ( figure 14 ) and in advanced position ( figure 15 ), the rear part 12b of the slider is engaged in the front part 11a of the guide allowing the two parts of the guide 11 and the slider 12 to be locked together. According to another characteristic of the invention, the movement mechanism 8 comprises a mechanism 28 for lifting the articulation axis 17 of the deformable structure relative to the supporting frame 2 during the sliding movement in the front-rear direction of the seat structure 3. This lifting mechanism 28 is adapted to initiate the opening of the deformable quadrilaterals 19, then allowing the jack 18 to ensure their deployment. This lifting mechanism 28 acts when the seat structure 3 moves from its nominal safety position to its retracted position. Thus, the nominal safety position is located upstream of the lifting mechanism 28.

[0041] In the embodiment illustrated in the drawings, the lifting mechanism 28 of the articulation axis 17 comprises at least one ramp 29 and in the illustrated example, two ramps 29 fixed to the supporting frame 2 and with which the deformable structure 16 cooperates. As is more precisely shown in figures 7 à 9 and 13, the ramps 29 extend parallel to the longitudinal plane of symmetry of the chair and each cooperate with a roller 30 carried for example by the first branch 20 of the quadrilateral. Thus, during the sliding movement of the seat structure 3 in the front-rear direction to move from its nominal safety position to its retracted position, each roller 30 cooperates with a ramp 29 leading to lifting the first branch 20 and subsequently, to lifting or shifting the articulation axis 17 relative to the second articulation point 23 of the first branch 20. In the retracted position of the seat structure 3 ( figure 10 ), the angle formed between the first branch 20 and the second branch 21 has opened so that the application of a tensile force by the jack 18 on the articulation axis 17 allows the deployment of the deformable structure 16 ( figure 13 ).

[0042] The movement of the seating structure 3 follows directly from the preceding description. When the wheelchair 1 is rolling, the seating structure 3 is placed in its nominal safety position relative to the supporting frame 2. The person controls, via the control unit 6, the extension of the cylinder 18 in order to position the seating structure 3 in this nominal safety position for which the seat 3b is substantially parallel to the supporting frame 2 and the center of gravity of the seating structure 3 is located in the central part of the support or lift polygon of the wheelchair 1. Of course, the extension of the cylinder 18 is controlled to move the seating structure 3 forward or backward depending on the conditions of use of the wheelchair.

[0043] When the person wishes to sit in the chair or get out of the chair, the cylinder 18 is controlled in extension to ensure the sliding of the seat structure 3 to a forward position. When the cylinder rod is extended, the slider 12 of the seat structure 3 is pushed and guided in translation by the guide 11. In particular, the rear part 12b of the slider 12 is engaged in the front part 11a of the guide 11 making it possible to lock together the two parts of the guide 11 and the slider 12 so that the seat structure 3 is moved into a stable position. The positioning of the seat structure 3 offset to the front of the chair facilitates the transfer operations of the person.

[0044] For the rolling of the wheelchair 1, the seat structure 3 is placed again in its nominal position relative to the supporting frame 2 ( figures 1 à 3 ). The person controls, by the control unit 6, the cylinder 18 in nominal sliding retraction in order to position the seat structure 3 in the nominal position for which the person is located in the central part of the support or lift polygon. During the retraction of the rod of the cylinder 18, the slide 12 of the seat structure 3 is pulled and guided in translation by the guide 11.

[0045] When the person wishes to position himself in a tilted position relative to the supporting frame 2, the cylinder 18 is controlled by the control unit 6, in retraction of recoil in order to position the seat structure 3 in its retracted position. Between the nominal safety position and the retracted position, the seat structure 3 is by its slide 12, pulled and guided in translation by the guide 11. During this movement, the rollers 30 of the seat structure cooperate with the ramps 29 leading to lifting the articulation axis 17 or to shifting it relative to the second articulation point 23 of the first branch 20. The angle formed between the first branch 20 and the second branch 21 has opened after passing over the ramps 29 ( figure 10 ). In this retracted position, the slider 12 is in contact with the retraction stop 15, and the rear part 12b of the slider is no longer engaged in the front part 11a of the guide 11 but cooperates only with the rear part 11b of the guide 11, thus allowing the seat structure 3 to tilt.

[0046] The cylinder 18 is controlled by the control unit 6, in tilting retraction to deploy the deformable structure 16 so as to position the seat structure 3 in a tilted position relative to the supporting frame 2. The rod of the cylinder 18 is retracted leading to opening the angle between the first branch 20 and the second branch 21 so that the seat structure 3 tilts backwards around the fourth articulation point 25 ( figures 11 à 13 and 16). The seat 3b is lifted and tilted backwards by an angle of up to, for example, 45°.

[0047] When the person wishes to return to the nominal safety position of the seating structure 3, the control unit 6 is controlled to control the cylinder 18 in tilting extension to fold the deformable structure 16 so as to position the seating structure 3 in a non-tilted position relative to the supporting frame 2. The rod of the cylinder 18 is extended, leading to closing the angle between the first branch 20 and the second branch 21 so that the seating structure 3 tilts forward around the fourth articulation point 25. The cylinder 18 is controlled by the control unit 6, in order to position the seating structure 3 in its retracted position.

[0048] It should be noted that the control unit 6 advantageously controls the jack 18 so that the seat structure 3 moves from its retracted position to the nominal safety position. For this purpose, the jack 18 is controlled in extension so that the slider 12 of the seat structure 3 is pushed and guided in translation by the guide 11. In particular, the front part 12a of the slider 12 cooperates with the front part 11a of the guide 11 while the rear part 12b of the slider 12 engages in the front part 11a of the guide 11. During this movement, the rollers 30 of the seat structure cooperate with the ramps 29 leading to lowering the articulation axis 17 and to substantially aligning it with the second articulation point 23 of the first branch 20.The extension of the jack 18 is stopped when the seat structure 3 is positioned in the nominal safety position for which the person is positioned in the central part of the support or lift polygon.

[0049] According to a characteristic of the invention, the chair 1 has the advantage of having a seat structure 3 that can be moved into several positions with a single jack 18. Thus, the seat structure 3 is able to occupy a nominal safety position suitable for rolling the chair but also a forward position to facilitate transfers of the person and a tilted position of the person towards the rear of the chair. The wheelchair according to the invention thus has a simple design by implementing a movement mechanism 8 of the seat structure 3 with a single jack.

Claims

1. A wheelchair for a disabled person or person with reduced mobility, comprising: - a supporting frame (2), - a seat base structure (3) for the person including at least one seat (3b) and a backrest (3c), - a movement mechanism (8) for moving the seat base structure (3) interposed between the frame (2) and the seat base structure (3), the movement mechanism (8) including: * a guide system (10) for guiding horizontal sliding of the seat base structure (3) in the front to back direction of the chair, * a deformable structure (16) interposed between the horizontal sliding guide system (10) and the seat base structure (3), this deformable structure (16) including a hinge pin (17) on which a motorized jack (18) mounted on the supporting frame (2) acts in order to move and deploy or fold the deformable structure, * a lifting mechanism (28) of the hinge pin (17) of the deformable structure (16) with respect to the supporting frame (2) during the sliding movement in the front to back direction of the seat base structure, - and a control unit (6) of the jack (18) adapted to control the jack: * in extension to ensure the sliding of the seat base structure (3) to an advanced position, * in nominal sliding retraction to ensure the sliding of the seat base structure (3) up to a nominal safety position, upstream of the lifting mechanism (28), * in withdrawal retraction to ensure the sliding of the seat base structure (3) to a withdrawn position and during which the lifting mechanism (28) acts to raise the hinge pin (17) to initiate the deployment of the deformable structure, * in tilting retraction to deploy the deformable structure (16) so as to position the seat base structure (3) in a tilted position with respect to the supporting frame (2).

2. The wheelchair according to claim 1, wherein the control unit (6) of the jack (18) is adapted to control the jack (18) in tilting extension to fold the deformable structure (16) so as to position the seat base structure (3) in a non-tilted position with respect to the supporting frame (2).

3. The wheelchair according to claim 1 or 2, wherein the deformable structure (16) includes at least one quadrilateral (19) formed by a first branch (20) and a second branch (21) articulated together about the hinge pin (17), the first branch (20) being linked by a second articulation point (23), to a slide (12) of the horizontal sliding guide system (10) while the second branch (21) is linked by a third articulation point (24), to the seat base structure (3), the slide (12) being linked to the seat base structure by a fourth articulation point (25).

4. The wheelchair according to the preceding claim, wherein the slide (12) comprises a front part (12a) linked by the second articulation point (23) to the first branch (20) and a rear part (12b) attached to the seat (3b) of the seat base structure via the fourth articulation point (25).

5. The wheelchair according to the preceding claim, wherein the horizontal sliding guide system (10) comprises a guide (11) including a front part (11a) attached on the supporting frame (2) to constantly guide the front part (12a) of the slide (12) and to guide the rear part (12b) of the slide in the forward position and nominal safety position, the guide (11) comprising a rear part (11b) attached to the seat (3b) of the seat base structure to receive the rear part (12b) of the slide to allow the tilting of the seat base structure.

6. The wheelchair according to one of the preceding claims, wherein the horizontal sliding guide system (10) includes an extension stop abutment (14) so that in the forward position, the seat base structure (3) protrudes at the front of the supporting frame, by between 10 cm and 30 cm.

7. The wheelchair according to one of the preceding claims, wherein the horizontal sliding guide system (10) comprises a withdrawal stop abutment (15) making it possible to position the seat base structure (3) in its withdrawn position.

8. The wheelchair according to one of the preceding claims, wherein the lifting mechanism (28) of the hinge pin (17) of the deformable structure (16) with respect to the supporting frame (3) includes at least one ramp (29) attached on the supporting frame with which the deformable structure (16) cooperates during the sliding movement of the seat base structure to initiate the deployment of the deformable structure.

9. The wheelchair according to the preceding claim, wherein the ramp (29) cooperates with a roller (30) carried by the first branch (20) of the quadrilateral (19) connected to the slide (12).