Standing chair

Abstract

A standing chair (10) for a user (20), preferably with a disability, the chair comprising a seat (12), a backrest (14), and a footrest (16). A mechanism for moving the seat (15) is adapted to move the seat between a first position corresponding to a "seated" position and a second position corresponding to a "sit-stand" position. The footrest is mobile along a horizontal axis H while remaining mechanically independent of the seat's movement. The coordinated kinematics of the seat and footrest are such that the user's center of gravity moves along a line following a vertical axis V.

Description

technical field

[0001] This disclosure relates to the field of standing chairs, that is to say chairs that allow a person to move from a "seated" position to at least a "seated-standing" position, particularly for people with reduced mobility and people with disabilities. Previous technique

[0002] People with disabilities who use wheelchairs suffer from physiological problems due to remaining in a seated position for extended periods. Furthermore, they are disadvantaged by not being at the same height as able-bodied people in everyday interactions.

[0003] To address these problems, standing chairs have been developed. They are articulated to allow the user to move from a seated position to a sit-stand or standing position. In the seated position, the user's torso is at approximately 90 degrees to their thighs. In the upright position, the user's torso is at approximately 180 degrees to their thighs. In the sit-stand position, the user is not completely upright, and their torso is at an angle between approximately 90 and 180 degrees. In one embodiment, the sit-stand position presents a torso angle of approximately 135 degrees to the thighs. The seated and sit-stand positions can be optimized for each individual user.

[0004] The benefits of standing upright include: by putting weight on the bones, it promotes better growth and helps prevent osteoporosis; it also improves blood circulation, bowel movements, and bladder emptying, thus preventing urinary tract infections. Finally, standing upright helps prevent skeletal deformities.

[0005] However, the verticalization process can often be uncomfortable for the user due to an often unnatural body movement. Summary

[0006] This disclosure improves the situation.

[0007] A standing chair is proposed, ideally for a user with a disability. The chair comprises a seat, a backrest, a footrest, and a seat movement mechanism adapted to move the seat between a first position corresponding to a "seated" position and a second position corresponding to a "sit-stand" position. The footrest is mobile along a horizontal axis H while remaining mechanically independent of the seat's movement. The coordinated kinematics of the seat and footrest are such that the user's center of gravity moves along a line following a vertical axis V.

[0008] The features described in the following paragraphs may optionally be implemented, independently of each other or in combination with each other: in the first position an angle αcThe angle between the user's spine in a straight position and a line Lp joining the user's hip joint to their knee joint is between 85 and 100 degrees; in the second position, the angle αc t is between 130 and 140 degrees. The seat movement mechanism is adapted to move the seat along a straight line of travel Co having an angle α 1 fixed with respect to the vertical axis V, the angle α1 being preferably between 8 and 3 degrees, and more preferably 5 degrees. The chair further includes a mechanism for moving the footrest along the horizontal axis. The footrest movement mechanism is adapted to move the footrest according to a kinematic dependent on the seat position. The kinematic is parabolic. The footrest movement mechanism is adapted to move the footrest according to the following kinematic: d = L c × cos α ci − L c 2 − c 2 − c × sin α l 2 + L c × cos α ci − c × sin α l × tan α ci 2 − c × sin α l where d is a distance of the footrest along the horizontal axis H between a position of the footrest when the seat is in the first position and a position of the footrest at a time t when the seat is between the first position and the second position, Lc the user's thigh length, α l the angle of the racing line Co of the seat relative to the vertical axis V, αLet φi be the initial angle of the user's thighs relative to the horizontal axis H, and c be the distance along the travel line Co between a hip joint position in the first seating position and a hip joint position at time t between the first and second seating positions. When the seat moves from the first to the second position, the footrest has a fixed orientation that remains constant at all times, and this fixed orientation is preferably at an angle αrp of 10 degrees relative to the horizontal axis. The footrest and / or the seat are free to pivot about a transverse axis T to the horizontal and vertical axes V. The coordinated kinematics of the seat and footrest are adapted to move the user's ankles and knees along horizontal lines.The coordinated kinematics of the seat and footrest are adapted to maintain the user's lower leg at a fixed angle αbdj with the horizontal axis H. The footrest is mounted on at least one rail, and in the absence of the user, it is free to move along the horizontal axis such that when the user is seated in the chair with their feet in the footrest and the seat is set in motion by the seat's motion mechanism, the movement of the footrest along the horizontal axis is passively transmitted by the user's body. When the seat is set in motion by the seat's motion mechanism, the seat remains fixed in a horizontal plane. The backrest is fixed relative to the seat. The chair is a self-balancing scooter. Brief description of the drawings

[0009] Other features, details, and advantages will become apparent upon reading the detailed description below and analyzing the attached drawings, on which: Fig. 1 [ Fig. 1 ] shows a standing chair with the user in a seated position according to one embodiment. Fig. 2 [ Fig. 2 ] shows the standing chair of the figure 1 with the user in a "sit-stand" position. Fig. 3 [ Fig. 3 ] shows a kinematic of the body of a wheelchair user Figures 1 And 2 , THE Figures 1 And 2 being superimposed on the figure 3 . Fig. 4 [ Fig. 4 ] shows a position of the user's torso when the chair is in the "sit-stand" position as well as associated reference angles. Fig. 5 [ Fig. 5 ] shows the position of the user's feet when the chair is in the "seated" position, along with associated reference angles. Fig. 6 [ Fig. 6 ] shows a kinematic relationship graph between the footrest and the seat of the chair. Fig. 7 [ Fig. 7 ] shows various usage positions between the "sitting" position (left) and the "sit-stand" position (right). Fig. 8 [ Fig. 8 ] shows the footrest of the chair according to one embodiment. Fig. 9 [ Fig. 9 ] shows the seat of the armchair according to one embodiment. Description of the implementation methods

[0010] Reference is now being made to Figures 1 And 2 which show a standing chair 10 in the "seated" and "sit-stand" positions respectively, according to one embodiment. In the "seated" position of the chair 10, the user 20 is seated and a torso 22 of user 20 (more specifically the spine 25 (in a straight line) is at a angle αct between 85 and 100 degrees relative to its thighs 24 (more precisely a LP line joining the hip joint 27 has the knee joint 23 ). There figure 1 illustrates a normal "seated" position of user 20 in the "seated" position of the chair 10. In the "sit-stand" position of the chair 10, user 20 is almost standing (i.e. almost in a vertical position), with the torso 22 of user 20 at an angle αct between 130 and 140 degrees relative to his thighs 24, preferably at 135 degrees.

[0011] The standing wheelchair 10 can be a wheelchair or a fixed wheelchair. If it is a wheelchair, it can be motorized or manual. In one embodiment, the wheelchair 10 is a self-balancing scooter. In the case of a self-balancing scooter, the user's center of gravity is used to maneuver the wheelchair.

[0012] The 10-seater chair includes a chassis 11 supporting a seat 12 adapted to accommodate the buttocks and in some cases the thighs of the user, 24, 20, a file 14on which user 20 can lean and a footrest 16 which receives the user's feet 20. One mechanism 15 for setting the seat in motion allows the seat 12 to be raised in order to move the chair 10 from the "seated" position to the sit-stand position, and vice versa.

[0013] To ensure the verticalization of the chair 10 (i.e., the movement towards the "sit-stand" position), the seat 12 (and therefore the user's hips) follows a Co-racing line straight line having a fixed angle α L compared to a vertical axis V. According to one embodiment, the angle α l is between 8 and 3 degrees, preferably 5 degrees. By adopting a non-strictly vertical line of travel Co, user ergonomics 20 is preserved during verticalization.

[0014] The movement mechanism 15 of the seat 12 can allow the user 20 to be positioned in any intermediate position to the extreme positions "sitting" and "sit-stand", following the line of travel Co.

[0015] In one embodiment, the seat 15 movement mechanism includes a cylinder, such as a hydraulic or pneumatic cylinder, to ensure a straight line of travel. The seat 15 movement mechanism can be controlled by the user 20 for activation and deactivation as required by the user 20.

[0016] The footrest 16 is movable relative to the seat 12 according to a horizontal axis H. Even if the footrest 16 moves between the "sitting" and sit-stand positions of the chair 10, the movement of the footrest 16 is mechanically independent of that of the seat 12, and remains along the horizontal axis H.

[0017] The vertical V and horizontal H axes are the natural axes defined when the chair 10 is in normal position on the ground.

[0018] According to one embodiment, the footrest 16 is free to move along the horizontal axis H. For example, the footrest 16 is mounted on one (or more) rail 17 arranged along the horizontal axis H, and is free of constraints along this axis, in the absence of the user 20. That is to say, when the user 20 is not seated in the chair 10, the footrest 16 can move freely along the horizontal axis H. On the other hand, when the user 20 is seated in the chair 10, its 28 feetare in the footrest 16, so that when the seat 12 is moved by the seat movement mechanism 15, the user's body 20 passively transmits this movement via the user's legs 20. Thus, when the seat 12 rises, the footrest 16 moves backward along the horizontal axis H passively by the user's body 20.

[0019] According to another embodiment, the footrest 16 has a movement along the horizontal axis H controlled by a footrest movement mechanism. The active movement mechanism of the footrest is independent of the movement mechanism of the seat.

[0020] According to one embodiment, the user 20 controls the kinematics of the footrest 16 himself. For example, when he wants to adjust a position of the footrest 16 once he has adjusted the seat 12.

[0021] Whether the footrest 16 has an actively or passively controlled movement, it moves along the horizontal axis H towards the seat 12 during standing and in the opposite direction to the seat 12 during the transition from the sit-to-stand position to the seated position. As previously stated, the seat 12 follows a straight line of motion Co with a fixed angle αl relative to the vertical axis V. It should be noted that when we speak of the position or movement of the seat along the travel line Co, we mean the position of the hip joint. Thus, if we decompose this travel line, it has a vertical component and a horizontal component. During standing, the footrest 16 and the horizontal component of the travel line Co of 12 move so as to move closer together horizontally. Conversely, during the transition from the sit-to-stand position to the seated position, the footrest 16 and the horizontal component of the travel line Co of the seat 12 move so as to move away from each other horizontally. This coordinated movement of the seat 12 and the footrest 16 contributes to the user's center of gravity moving along a vertical line during standing and vice versa.This shift of the center of gravity along a vertical line is particularly advantageous when the chair is a gyropod since it avoids uncontrolled movements of the chair when verticalizing and moving from the sitting-standing position to the sitting position.

[0022] According to one embodiment, the footrest movement mechanism is programmed to move the footrest 16 according to a kinematics that depends on that of the seat 12 in order to maintain an optimal anatomical position for the user 20. The footrest movement mechanism 16 provides a mechanically independent displacement of the footrest from that of the seat, even if the kinematics may depend on that of the seat 12. The footrest 16 and the seat 12 have a coordinated movement, but it is possible that for certain parts of the movement, such as the beginning or end of the movement, only the seat 12 or only the footrest 16 moves.

[0023] In one embodiment, the kinematics of the footrest 16 are a pure function of the displacement of the seat 12. In another embodiment, these kinematics are a parabola. In yet another embodiment, the dependence of the kinematics of the footrest 16 on the displacement of the seat 12 may take into account the user's physiological characteristics and / or the angle of the seat's travel line Co.

[0024] According to one embodiment and as illustrated in the figure 6 , The kinematics of footrest 16 are as follows: d = L c × cos α ci − L c 2 − c 2 − c × sin α l 2 + L c × cos α ci − c × sin α l × tan α ci 2 − c × sin α l Or d is a distance of the footrest 16 along the horizontal axis H between a position of the footrest when the user 20 is in the "seated" position and a position of the footrest at a time t between the "seated" position and the "sit-stand" position, Lc thigh length 24 of user 20, α l the angle of the racing line Co of the seat 12 with respect to the vertical axis V, α this is an initial anglethe user's thighs 24 20 relative to the horizontal axis H, and c is the distance along the race line Co between a position of the hip joint 27 in the "seated" position and a position of the hip joint 27 at time t between the "seated" position and the "sit-stand" position. The distance d varies according to the distance c, which itself varies over time when moving from the "seated" position to the sit-stand position and vice versa. Physiological data such as thigh length or limb angles can be adapted to each user or can be taken from observed averages.

[0025] The specific movement described above can be particularly advantageous because it is gentle on the user's joints. The degree of rotation of the knee and hips relative to each other ensures a smooth movement of the body between sitting-to-standing and sitting positions.

[0026] According to one embodiment, whether the movement of the footrest 16 is free or controlled along the horizontal axis H, the footrest 16 has a fixed orientation ( corner αrp) and identical at all times. The fixed orientation of the footrest 16 is preferably at an angle α rp between 0 and 15 degrees, preferably at 10 degrees with respect to the horizontal axis H. According to one embodiment, and as illustrated in the figure 5 , A angle α pt formed by the feet 28 and tibias 26 of the user 20 is at 90 degrees. This angle can then remain constant during standing and when transitioning from a sit-to-stand to a seated position. Maintaining this constant angle can be particularly beneficial for quadriplegic patients since it allows the ankle 21, lower leg 19 and knees 23 to be fixed.

[0027] Thus, a kinematic system is preferred that allows the ankle 21 and knees 23 to move along horizontal lines parallel to the lower leg 19 at a constant inclination during verticalization (angle αbdj between a straight line joining the ankle and the fixed knee relative to the horizontal). figure 7 This shows an example of such kinematics. The ankles 21 move along a horizontal line H2 during the verticalization of the chair (verticalization being observed by viewing the stylized patient from left to right in the figure), and during the transition from the sit-to-stand to the seated position. The knees 23 move along a horizontal line H1 during the verticalization of the chair, and during the transition from the sit-to-stand to the seated position. The lower leg 19 remains at a constant angle during verticalization. The kinematics of the figure 6is an example of kinematics which allows the ankles 21 and knees 23 to be kept on parallel horizontal lines.

[0028] According to one embodiment and as illustrated in the figure 8 , Whether the movement of the footrest 16 is free or controlled along the horizontal axis H, the footrest 16 is free to pivot around a transverse axis Tto the horizontal axis H and to a vertical axis V (angle αd). The transverse axis T corresponds to the axis of rotation of the knee 23 and ankle 21 joints of the user 20. This embodiment allows for the footrest 16 to move when the user 20 is seated, independently of the lifting movement of the seat 12. Considering the lifting movement of the seat 12, the combination of this arrangement of the footrest 16 (pivot) during its horizontal movement improves user 20 comfort, as the footrest 16 automatically positions itself at the optimal angle αd according to the user's load applied to it.

[0029] According to one embodiment, whether the movement of the footrest 16 is free or controlled along the horizontal axis H, the seat 12 remains fixed in a horizontal plane during its verticalization movement.

[0030] According to another embodiment and as illustrated in the figure 9 , Whether the movement of the footrest 16 is free or controlled along the horizontal axis H, the seat 12 can pivot about the transverse axis T relative to the horizontal axis H and a vertical axis V (angle αb). This transverse axis T corresponds to the hip joint 27 of the user 20. The pivot of the seat 12 about the transverse axis T can be free or controlled. Considering the lifting movement of the seat 12, the combination of the pivoting of the seat 12 with its lifting function improves user comfort, as the seat 12 automatically positions itself at the optimal angle according to the load applied to the user 20.

[0031] In the embodiments presented above, the backrest 14 can be fixedly connected to the seat 12. In this case, the backrest 14 moves along a line parallel to the line of travel Co, while remaining in a vertical plane.

[0032] The kinematics developed in the presented embodiments allow the user's center of gravity 20 to evolve during lifting along a perfectly vertical line. In the case of a gyropod base for the wheelchair 10, this ensures that the movement will have no influence on the stability of the base.

[0033] The angles presented in this application must be considered with their margin of tolerance as is customary in the technical field of the invention.

Claims

1. Standing chair (10) for a user (20) preferably for people with disabilities, the wheelchair includes: - a seat (12), A file (14), A footrest (16); and - a seat movement mechanism (15) adapted to move the seat between a first position corresponding to a "sitting" position and a second position corresponding to a "sit-stand" position, characterized in that the footrest is movable according to a horizontal axis H while being mechanically independent of the seat's movement, and with coordinated kinematics of the seat and footrest such that the user's center of gravity moves along a line following a vertical axis V.

2. Armchair according to the preceding claim, wherein in the first position a angle αc t between the spine (25) of the user in a straight line And a LP line joining the hip joint (27) has the knee joint (23) The user's angle is between 85 and 100 degrees; in the second position, the angle αc tis between 130 and 140 degrees.

3. Armchair according to the preceding claim, wherein the seat movement mechanism is adapted to move the seat along a Co-racing line straight line having a corner α l fixed with respect to the vertical axis V, the angle α l being preferably between 8 and 3 degrees, and more preferably 5 degrees.

4. Armchair according to claim 2 or 3, further comprising a mechanism (15) for moving the footrest to move the footrest along the horizontal axis.

5. Armchair according to the preceding claim, in which the footrest movement mechanism is adapted to move the footrest according to a kinematic dependent on a seat position.

6. Armchair according to the preceding claim, in which the kinematics are of parabolic form.

7. Armchair according to the preceding claim, in which the footrest movement mechanism is adapted to move the footrest according to the following kinematics: d = L c × cos α ci − L c 2 − c 2 − c × sin α l 2 + L c × cos α ci − c × sin α l × tan α ci 2 − c × sin α l Or d is a distance from the footrest (16) along the horizontal axis H between a position of the footrest when the seat is in the first position and a position of the footrest at a time t when the seat is between the first position and the second position, Lc thigh length (24) of the user, α l the angle of the racing line Co of the seat relative to the vertical axis V, α This is an initial angle of the thighs. of the user relative to the horizontal axis H, and c is the distance along the race line Co between a position of the hip joint in the first sitting position and a position of the hip joint at time t between the first and second sitting positions.

8. An armchair according to any one of the preceding claims, wherein when the seat moves from the first to the second position, the footrest has a fixed and identical orientation at all times, and the fixed orientation of the footrest is preferably at one angle α Rp 10 degrees relative to the horizontal axis.

9. Armchair according to any one of claims 1 to 7, wherein the footrest and / or the seat is free to pivot around a transverse axis T to the horizontal axis and to the vertical axis V.

10. Armchair according to the preceding claim, in which the coordinated kinematics of the seat and footrest is adapted to move the user's ankles and knees along horizontal lines.

11. Armchair according to any one of the preceding claims, wherein the coordinated kinematics of the seat and footrest are adapted to maintain a lower leg (19) of the user at a fixed angle αbdj with the horizontal axis H.

12. Armchair according to any one of the preceding claims, in which the footrest is mounted on at least one rail (17), and in the absence of the user, the footrest is free to move along the horizontal axis so that when the user is seated in the chair with their feet in the footrest and the seat is set in motion by the seat movement mechanism, the movement of the footrest along the horizontal axis is passively transmitted by the user's body.

13. Armchair according to any one of the preceding claims, wherein when the seat is set in motion by the seat-setting mechanism, the seat remains fixed in a horizontal plane.

14. Armchair according to one of the preceding claims, in which the backrest is fixed in relation to the seat.

15. Armchair according to any one of the preceding claims, wherein the armchair is a gyropod.

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