EP2004124A1

EP2004124A1 - Multi-position chair for handicapped user

Info

Publication number: EP2004124A1
Application number: EP06726299A
Authority: EP
Inventors: François Porcheron
Original assignee: Lifestand "Vivre Debout"; Lifestand Vivre Debout
Current assignee: Lifestand "Vivre Debout"
Priority date: 2006-04-03
Filing date: 2006-04-03
Publication date: 2008-12-24
Anticipated expiration: 2026-04-03
Also published as: WO2007113395A1; EP2004124B1; US20090218784A1; US8128120B2; ATE555765T1; CN101460133A

Abstract

According to the invention, the wheelchair is characterized in that it includes means to incline the whole seat structure, and inclining means that are interposed between the chassis and the lifting means and that include at least: a base (65) that is attached to the chassis (1) and that oscillates around a more-or-less horizontal axis, and on which the lifting means are fitted, and a mechanical assistance means that is interposed between the base (65) and the chassis (1) and that is designed to allow modification of the slope of the whole seat structure by rotation of the base (65).

Description

MULTIPOSITION ARMCHAIR FOR HANDICAP

The invention relates to the technical field of multiposition seats for disabled allowing a user to move, for example, from a low sitting position to a high sitting position.

In a preferred but non-exclusive application, the invention relates to the field of wheelchairs for persons with disabilities or reduced mobility which include elevating means ensuring a user elevation placed on the seat, so as to enable him, by for example, to reach objects placed high while sitting.

In the above field, an international application WO 92/15271 has, for example, proposed a wheelchair for handicapped comprising a wheeled undercarriage. The chair is further conventionally equipped with a seat structure that includes at least one footrest, seat and backrest. The chair comprises, finally, lifting means, interposed between the frame and the seat structure, to allow a change in the height of the seat structure.

According to the application WO 92/15271, the elevating means comprise, for this purpose, an articulated assembly composed, on the one hand, of a parallelogram, deformable in a vertical plane, interposed between the frame and the seat structure and, on the other hand, a mechanical assistance means adapted to allow, by deformation of the parallelogram, a change in the seat height.

Such a chair fully fulfills its function of raising-lowering the user. However, it appeared that such a chair was not able to allow easy modification of the inclination or the general base of the seat structure to, for example, adopt the seating structure a reclined position and allow relaxation for the wheelchair user, while decreasing the pressure on the ischium and buttocks to reduce the risk of pressure ulcers and shear effects due to changes in position. The invention aims to remedy ^one that drawback by proposing ways to tilt the entire seat structure to ensure a modification of the general inclination or attitude of the latter in a simple manner , without profound modification of the chair's design. In order to achieve this objective, the invention therefore relates to an armchair for a handicapped person or person with reduced mobility, comprising:

• a carrier chassis,

• a seating structure that includes at least:

* a footrest, 4 a seat,

* and a folder,

And elevating means, interposed between the frame and the seat structure, allowing a modification of the height of the seat structure. According to the invention, this chair is characterized in that it comprises means of inclination of the whole of the seat structure, inclination means which are interposed between the frame and the seat structure and which comprise at least :

A base, secured to the frame, which oscillates about a substantially horizontal axis and on which the lifting means are adapted,

And a mechanical assistance means interposed between the base and the frame and which is adapted to allow, by a rotation of the base, a modification of the inclination of the whole of the seat structure, independently of its configuration.

According to the invention, the chair is also characterized in that the lifting means comprise at least:

an articulated assembly which comprises at least one deformable polygon in a vertical plane, interposed between the seat structure and the base which then defines one side of the deformable polygon, and a mechanical assistance means adapted to allow, by a deformation of the polygon, a change in the height of the seat structure.

Thus, the implementation of the base associated with the mechanical assistance means makes it possible, very simply, to modify the overall inclination of the seat structure, independently of the configuration adopted for the latter and, in particular, any by being able to maintain the desired seat height.

According to the invention, the means of mechanical assistance of the tilting means can be made in any suitable manner and, for example, include a manually operated system, such as, for example, a screw jack driven by means of a flywheel equipped with a crank or, preferably, be motorized by being, for example, in the form of an electric jack interposed between the base and the frame. According to the invention, in order to ensure greater stability of the seat structure relative to the chassis, the articulated assembly of the elevation means comprises at least two deformable polygons in two parallel vertical planes.

According to the invention, it is possible to adopt several forms for the deformable polygons but, preferably, these deformable polygons are quadrilaterals which will be chosen, advantageously but not strictly necessary, to be parallelograms.

In a preferred but not strictly necessary embodiment of the chair according to the invention, the latter is designed to form what could be called a multiposition chair and the seat structure is then chosen to be articulated.

For this purpose, the seat structure comprises:

• support structures for the backrest, seat and footrest that are hinged to allow a modification of the relative inclination of the backrest relative to the seat and / or a modification of the relative inclination of the footrest with respect to the seat,

And at least one mechanical assistance means adapted to ensure a modification of the relative inclination or of the relative angle of the backrest with respect to the seat and / or a modification of the relative inclination or the relative angle of the seat. footrest relative to the seat. Such an articulated seat structure makes it possible, for example, by modifying the inclination with respect to the seat, on the one hand, of the backrest and, on the other hand, of the footrest, of offering the possibility of placing the seat structure in an elongate position by placing, for example, the footrest, the seat and the backrest, in the extension of each other, in a substantially horizontal plane.

Similarly, it is possible to place the articulated seat structure in a relaxed position. In the elongated configuration for example, the means for tilting or modifying the general inclination of the seat structure can then be very advantageously used to place the seat structure in a forward inclined position. or, on the contrary, tilted backwards. Thus it is possible to place the wheelchair user lying upside down, in order to apply a technique of respiratory physiotherapy called "claping".

The combination of the articulated nature of the seat structure and the inclination means of the latter makes it possible to place the chair, according to the invention, in an infinity of configurations, able to meet the medical needs of the chair user.

In a still more particularly preferred form, the seat structure and the mechanical assistance means are adapted to allow the passage of the seat structure in a standing position, in which the footrest, the seat and the backrest are placed in the extension of each other, in a substantially vertical plane. Here again, the combination of the articulated nature of the seat structure and the implementation of the tilting means of the latter makes it possible, when the user is in a vertical position, to adopt a slight inclination towards the rear the vertical seating structure, so as to provide the user with a sense of security.

According to the invention, the seat structure can also be adapted to allow, on the one hand, the passage of the seat structure in the vertical position and, on the other hand, the passage of the same structure sitting in the so-called elongated position. According to another characteristic of the invention, the backrest arm is formed by a motorized jack constituting a mechanical assistance means for modifying the relative inclination of the backrest relative to the seat.

In the same sense, according to a feature of the invention, the leg arm is formed by a motorized cylinder constituting a mechanical assistance means for modifying the relative inclination of the footrest relative to the seat.

Preferably, the chair according to the invention is intended to allow movement of the user and, for this purpose, it forms a wheelchair whose chassis comprises at least three wheels. In order to give complete autonomy to the user, at least one of the wheels will preferably, but not necessarily, motorized, in which case its operation will be controlled by means of the control unit mentioned above.

Various other characteristics appear from the description below made with reference to the accompanying drawings which illustrate a preferred but non-limiting embodiment of a chair according to the invention.

Fig. 1 is a three-quarter front perspective of the chair according to the invention in a low or normal sitting position of the seat structure. Fig. 2 is a side elevation of the chair, according to FIG. 1, in the low sitting position. Fig. 3 is a perspective of three quarters rear of the chair, according to fig. 1, in vertical position of the seat structure.

Fig. 4 is a side elevation of the chair, in the position according to FIG. 3. The fg. 5 is a three-quarter front view of the chair, according to FIG. 1, in an elongated position inclined towards the rear of the seat structure.

Fig. 6 is a side elevation of the chair, in the position according to FIG. 5. FIG. 7 is an elevation, similar to FIG. 2, the chair in a sitting high position of the seat structure.

Fig. 8 is an elevation, similar to FIG. 2, the chair in a so-called relaxed position of the seat structure.

Fig. 9 is an elevation, similar to FIG. 2, the chair in an extended position of the seat structure.

Fig. 10 is a perspective similar to fig. 3 showing another embodiment of a chair according to the invention.

An armchair according to the invention, as illustrated in FIGS. 1 to 6, comprises a support frame 1 on which a seat structure 2 is fitted. According to the illustrated embodiment, the chassis 1 comprises two front-wheel-drive wheels 3, each supported by a suspension arm 4. The chassis 1 comprises, in in addition, two rear wheels 5, so-called crazy, insofar as they are connected to the frame 1 by a pivot 6 of substantially vertical axis.

In order to allow changes in the direction of the wheelchair during its movement, each drive wheel 3 is equipped with an electric geared motor 7 powered by a set of batteries 8 and controlled by a control unit 9 provided with a handle 10. The control unit 9 allows, by means of the lever 10, to ensure synchronized control or not the driving wheels 4 so as to advance, backward, turn left or right, the chair according to the invention. Of course, it should be considered that such an embodiment of the carrier frame 1 is not strictly necessary for the invention and, thus, the carrier frame could include no motorized wheel and be, for example, designed for a manual movement. Conventionally, the seat structure 2 comprises a footrest

15, a seat 16 and a backrest 17. Preferably but not strictly necessary for producing a chair according to the invention, the seat structure 2 is articulated so as to allow a modification of the relative inclination of the backrest 17 relative to the seat 16 and / or a modification of the relative inclination of the footrest 15 with respect to the seat 16.

For this purpose and in the embodiment more particularly illustrated in the figures, the seat structure 2 comprises a cross member 19 which is located in the front region of the chair.

The seat structure also comprises a structure 20 for supporting the seat 16, which is composed of at least one and, according to the illustrated example, of two longitudinal members 21 which are integral with the seat and which, according to the illustrated example, help define a support framework for the latter. Preferably, the rails 21 are made in two parts 21i, 2I ₂ to allow adjustment of the seat depth according to the size and build of the chair user.

The front portions 21i of the two longitudinal members 21 are articulated at the front on the anterior cross member 19 via pivots 22 of substantially horizontal axes. The articulated support structure 20 of the seat 16 further comprises a motorized telescopic ram 23, constituted, for example but not exclusively, by an electric screw jack. The motorized telescopic ram 23 is then articulated at the front on the anterior cross member 19 by a pivot 24 of axis also horizontal and, at the rear, on the longitudinal members 21 and / or as illustrated on an element such as a crossbar 25 connected to the front portions 21i of the two longitudinal members 21 and constituting the articulated structure 20 for supporting the seat 16. The telescopic ram motorized 23 is then attached to the cross member 25 via a pivot 26 of horizontal axis.

The seat structure 2 also includes an articulated structure

The backrest support structure 30 comprises at least one and, according to the illustrated example, two uprights 31 which are integral with the backrest 17 and which are hinged to the rear parts 2I ₂ of the longitudinal members 21.

According to the illustrated example, the uprights 31 are more particularly connected by a cross member 32 which is then itself hinged to the longitudinal members 21 of the seat support structure 20, via pivots 33 of horizontal axes.

The articulated support structure 30 of the backrest 17 further comprises a backrest arm 35 placed under the seat 16, as is more particularly apparent from FIG. 4. This folder arm 35 is preferably, but not necessarily, made in two parts, respectively anterior 36 and posterior 37, which allow a permanent adjustment of the length of the backrest arm 35, depending in particular on the seat depth . The anterior portion 36 of the backrest arm is hinged to the anterior cross member 19, via a pivot of horizontal axis 39, while the rear portion 37 is articulated by a pivot 40, also of substantially horizontal axis , on the uprights 31 or an integral element thereof, in this case a finger 32i forming an integral part of the crossbar 32.

According to a preferred but not strictly necessary embodiment, the length of the backrest arm 35 is adjustable so as to adjust the relative inclination of the backrest 17 relative to the seat 16. For this purpose and according to the illustrated example, the part front 36 of the arm 35 is formed by a telescopic motorized jack, such as, for example, an electric screw jack whose operation is controlled by the control unit 9.

In order to allow a continuous and automatic modification of the length of the back segment, namely the distance between the seat 16 and the backrest 17, during the modification of their relative inclination, the backrest 17 is, preferably, fitted to each upright 31 by means of a slider 42 which is further connected to the seat support structure 20 by means of a link 43.

The seat structure 2 also comprises an articulated structure 50 for supporting the footrest 15. The structure 50 then comprises at least one and, according to the illustrated example, exactly one leg segment 51 which is connected to the footrest 15 and which is articulated on the anterior cross member 19 by means of a pivot 52 of horizontal axis.

The articulated footrest support structure 50 also comprises at least and, according to the illustrated example, exactly one leg arm 53 which is hinged, on the one hand, on the anterior cross member by a pivot

54 of horizontal axis and, secondly, on the leg segment 51 also via a pivot 55 axis also horizontal.

Preferably, the leg arm 53 has an adjustable length, to allow a modification or adjustment of the relative inclination or inclination of the leg segment 51 with respect to the seat 16 and therefore, a modification of the position relative angle of the footrest 15 with respect to the seat 16.

According to the illustrated example, for this purpose and preferably, the leg arm 53 is constituted by a motorized telescopic jack, such as an electric screw jack, controlled by the unit 9, as will appear more particularly by the after.

In order to allow an automatic modification of the distance between the footrest 15 and the seat 16, as may be necessary when changing the relative angular position of these two elements, the footrest 15 is, according to the example illustrated and preferably, adapted on the tibial segment 51 via a carriage 56.

According to the illustrated example, this carriage 56 is then connected, by connecting means 57, to the seat 16 or the seat support structure 20, so as to allow an automatic modification of the distance between the seat 16 and the footrest 15, during the modification of the relative inclination of the tibial segment 51 with respect to the seat 16.

According to a feature of the invention, the chair further comprises elevator means 60, interposed between the frame 1 and the seat structure 2 to allow a change in the height of the seat structure.

The lifting means could be made in different ways and, for example, constituted by a single jack, interposed between the frame 1 and the seat structure 2 and, for example, between the frame and the front cross member 2. However, according to a preferred embodiment of the invention and in order to have greater stability and rigidity, the lifting means 60 comprise at least one articulated assembly which consists of at least one and, according to the illustrated example, two deformable polygons 61 in two parallel vertical planes. According to the illustrated example, each deformable polygon 61 has the shape of a deformable parallelogram whose two long sides are formed by two segments or lower arm 62j and upper 62 _S which are hinged forward on the anterior cross member 19 by pivots 63j, 63 _s of substantially horizontal axes. The anterior cross member 19 then forms a small side of the deformable parallelograms 61. It should be noted that, according to the illustrated example, the axis of the pivots 63 _S of the upper arms 62 _S coincides with the axis of the pivots 22 of the structure articulated seat support 20. The segments or arms 62j, 62 _S are, moreover, hinged at their rear end on a base 65, integral with the frame and hinged to the latter by means of a substantially axis pivot horizontal 66.

According to the illustrated example, the base 65 comprises two spreaders 67 which each form the short side of a deformable parallelogram 61, being connected to the corresponding segments 62j, 62 _S by pivots 68j, 68 _S of substantially horizontal axis. It will be noticed that, according to the illustrated example, the articulation pivots 68j, the lower segments 62j with the rudder corresponding 67, have an axis coincident with the oscillation axis of the base

65 on the chassis 62.

The elevation means further comprise a mechanical assistance means 70 interposed between the base 65 and the upper segment 62 _S to allow, by deformation of the deformable polygons or parallelograms 61, a modification of the height of the 'seated.

Naturally according to the invention the mechanical assistance means 70 could be interposed between the base and another segment of the deformable parallelograms 61. Preferably, the mechanical assistance means 70 are constituted by a motorized telescopic jack, such as an electric screw jack, controlled by the unit 9.

Finally, the chair 2 comprises a mechanical assistance means, such as, for example, an electric motor screw jack 73, interposed between the frame 2 and the base 65, so as to modify the relative angle. Thus, the base 65 and the cylinder 73 together define tilting means of the entire seating structure, as will appear later.

The chair, as described above, operates in the following manner. First of all, it must be remembered that all mechanical assistance bodies, consisting of:

The motorized telescopic ram 70 of the elevation means,

The motorized telescopic ram 23 of the articulated support structure of the seat 16, the motorized telescopic ram 36 of the articulated support structure of the backrest 17,

The motorized telescopic ram 53 of the articulated support structure 50 of the footrest 15,

• and the motorized telescopic ram 73 means of inclination of the whole of the seat structure 2, are all controlled by the control unit 9. Preferably, the control unit 9 is then designed to allow individual control of each of these cylinders. Thus, the user of the chair according to the invention can control a raising / lowering movement of the entire seating structure by a control of the motorized telescopic ram 70, called "lift" which ensures a modification of the height of the seat 16. It is therefore possible for the user of the chair to control a passage from the low or normal sitting position as illustrated in FIG. 1 at the high sitting position as illustrated in FIG. 7 Similarly, then, regardless of the height of the seat structure or seat 16, the user can also, through the unit 9, provide a control of the motorized telescopic ram 73, said plate , and modify the general inclination or attitude of the seat structure to, for example, tilt it backwards and move into a relaxed position as shown in FIG. 8.

It should be noted that this attitude change movement does not affect the overall configuration of the seating structure.

The user can also, by controlling, by means of the control unit 9, the cylinders 36 and 53 modify the relative inclination of the backrest relative to the seat, as well as the inclination of the footrest relative to the seat, so that it can place the chair according to the invention in different configurations such as semi elongated or completely elongated, as shown in FIG. 9, configuration in which the backrest 17, the seat 16 and the footrest 15 are then substantially aligned in a horizontal plane.

In a preferred embodiment, the control unit 9 is adapted to allow automatic passage in the extended position by a coordinated control of the backrest cylinders 36 and footrest 53.

In this elongated configuration, the user still has access to the raising / lowering function and can, for example, by a control of the lift jack 70 choose to place the seat structure in configuration berth at the desired height to allow the transfer of the user of the chair on an examination table or in a bed.

Moreover, in this configuration, the user also has access to the general inclination function of the entire seating structure and can, for example, tilt it backwards, even though is in the sleeping position. This inclined backward position, called "proclive", illustrated in FIG. 5 and 6, may be useful for the technique of respiratory physiotherapy called "claping".

According to the invention, the chair can, from the normal sitting position fig. 1, by the sole control of the motorized cylinder 23, to move to the verticalization position 4. Indeed, given the relationship between the articulated support structures of the seat 16, the backrest 17 and the footrest 15, the only command motorized telescopic ram 23 makes it possible to move from the seated position to the upright position, as illustrated in FIGS. 3 and 4.

The maneuvering of a single jack, called verticalization, 23 to ensure this verticalization of the seat structure has the advantage of offering a very great comfort and a sense of security, insofar as this movement can be assured of Automatically by the control unit, smoothly and with great fluidity.

Of course, the control unit 9 will then be programmed to ensure that the seat structure 2 is, before the initiation of the vertical movement, located at a height sufficient to prevent any risk of blocking the movement by a contact of the footrest with the ground.

Furthermore, it should be noted that in verticalization position, the elevation function, provided by the lift cylinder 70, remains accessible. Similarly, the general inclination function of the entire seat structure is, in the position of verticalization, also accessible by the control of the attitude cylinder 73, so that it is possible to choose a slightly inclined position backwards helping to give the chair better stability and to bring a sense of security to the wheelchair user who no longer has the use of his lower limbs.

In order to offer a very great flexibility and ease of use, the control unit 9 is moreover adapted to ensure by a coordinated operation of the verticalizing cylinders 23, 36 and tilting 53, an automatic passage of the vertical position fig. 4 in the extended position Fig. 9 and conversely with, optionally, a possibility of stopping in an intermediate position. This movement is then achieved by maintaining the alignment of the footrest, seat and back substantially in the same plane.

It should be noted that, in order to guarantee the safety of use in a vertical position, the chair will be equipped with chest restraint means, not shown and constituted, for example, by a belt or harness, as well as low retaining means. 80 formed, according to the example shown, knee pads coming to apply pressure on the knees, to prevent sagging of the user of the chair in the vertical position.

Similarly, in the usual manner for a chair for the disabled, the chair according to the invention comprises two armrests 81 secured to the backrest structure 20. According to the illustrated example, the control unit 9 is fitted on the armrest 81 of right.

According to the example illustrated and described above, the backrest 17 is connected to the seat support structure 20 by a connecting rod 43. However, such a rigid connection mode is not strictly necessary for the production of a chair according to the invention. invention. Thus, FIG. 10 shows another embodiment of a disabled multiposition chair according to the invention which differs from the embodiment as described with reference to FIGS. 1 to 9 in that the backrest 17 is supported by a single amount 90 hinged to the support structure 20 of the seat 16. The backrest 17 is then connected to a slide which is movable in the upright 91. The file is further connected to the seat support structure by a flexible belt, not shown, guided by a pulley system, also not shown, so as to ensure an increase in the distance between the backrest 17 and the seat 16 during the transition to the vertical position.

The embodiment illustrated in FIG. 10 is also different in that the rear wheels 3 are driving while the front wheels 5 are crazy. The motorized chair shown in fig. 10 can therefore be described as powered wheelchair as opposed to the chair illustrated in Figs. 1 to

9 which can be described as a traction chair. In the context of the embodiment illustrated in FIG. 10, the placement of the motors 7 at the rear allows to roll back the masses and thus to increase the stability of the chair in position of verticalization in particular.

Claims

1 - Armchair, for a disabled person or a person with reduced mobility, comprising: • a carrying frame (1),

A seating structure (2) which comprises at least:

* a footrest (15),

* a seat (16),

* and a backrest (17), and lifting means (60) interposed between the frame (1) and the seat structure (2) allowing a modification of the height of the seat structure, characterized in that it comprises means for inclining the whole of the seat structure (2), tilting means which are interposed between the frame and the lifting means and which comprise at least:

A base (65) which is integral with the frame (1) and which oscillates around a substantially horizontal axis and on which the lifting means are adapted,

And a mechanical assistance means (73) which is interposed between the base (65) and the frame (1) and which is adapted to allow, by a rotation of the base (65), a modification of the inclination of the entire seat structure (2), regardless of its configuration and in particular the seat height and in that the lifting means comprise at least: • an articulated assembly which comprises at least one deformable polygon

(61) in a vertical plane, interposed between the seat structure and the base which then defines a side of the deformable polygon,

And a mechanical assistance means (70) adapted to allow, by a deformation of the polygon (61), a change in the height of the seat structure (2). 2 - Chair according to claim 1, characterized in that the articulated assembly (60) comprises at least two polygons (61) deformable in two parallel vertical planes.

3 - Chair according to claim 1 or 2, characterized in that each deformable polygon (61) has the form of a deformable quadrilateral whose two sides are formed by two articulated segments connecting the frame to the seat structure.

4 - Armchair according to claim 3, characterized in that the deformable quadrilateral (61) has the shape of a parallelogram. 5 - Chair according to one of claims 1 to 4, characterized in that the mechanical assistance means (73) means for tilting the entire seating structure (2) is motorized.

6 - Chair according to one of claims 1 to 5, characterized in that the seat structure (2) is articulated and comprises: • support structures of the backrest (17), the seat (16) and the seat foot (15) which are articulated to allow a modification of the relative inclination of the backrest relative to the seat and / or a modification of the relative inclination of the footrest with respect to the seat, • and at least one means of assistance mechanical mechanism (23, 36, 53) adapted to provide a modification of the relative inclination of the backrest relative to the seat and / or a modification of the relative inclination of the footrest relative to the seat.

7 - Chair according to claim 6, characterized in that the articulated seat structure (2) and the mechanical assistance means (23) are adapted to allow the passage of the seat structure in a position of verticalization in which the footrest (15), the seat (16) and the backrest (17) are placed in the extension of each other in a substantially vertical plane. 8 - Armchair according to claim 6 or 7, characterized in that: The seat structure (2) comprises a cross member (19) which is located in the front region of the chair and which forms a side of the deformable polygon (61) of the lifting means (60),

The articulated structure (20) for supporting the seat comprises at least: a spar (21) which is integral with the seat (16) and which is articulated at the front on the front cross member (19),

* and a motorized telescopic jack (23) which is articulated, at the front, on the front cross member (19) and, at the rear, on the spar or a member (25) secured to the spar and which forms a means of mechanical assistance to the verticalization of the seat structure (2),

The articulated structure (30) for supporting the backrest (17) comprises at least:

* an amount (31) which is secured to the backrest and which is articulated on the rear end of the spar (21) or on an integral element of the spar,

* and a backrest arm (35) which is articulated on the anterior cross member (19) and on the upright (31) or an element (32) integral with the upright, • and the articulated structure (50) of support of the footrest (15) includes at least:

* a tibial segment (51) which is integral with the footrest and which is articulated on the anterior crossbar (19),

* a leg arm (53) which is articulated on the one hand, on the anterior cross member (19) and, on the other hand, on the leg segment (51).

9 - Chair according to claim 8, characterized in that the backrest arm (35) comprises an anterior segment (36) formed by a motorized jack (36) constituting a mechanical assistance means for modifying the relative inclination of the backrest (17) relative to the seat (16). 10 - Armchair according to claim 8 or 9, characterized in that the leg arm is formed by a motorized jack (53) constituting a mechanical assistance means for modifying the relative inclination of the footrest (15) by report to headquarters (16). 11 - Armchair according to one of claims 8 to 10, characterized in that it comprises a control unit (9) which controls the motorized cylinders and which is suitable for:

• on the one hand, automatically place the seat structure (2) from a so-called normal position: * either in a vertical position in which the footrest (15), the seat (16) and the backrest (17) are aligned in a substantially vertical plane, * in an extended position, in which the footrest, the seat and the backrest are aligned in a substantially horizontal plane, and secondly, allow, in a semi-automatic, a modification of the elevation of the seating structure.

12 - Chair according to one of claims 8 to 11, characterized in that the footrest (15) is adapted to the leg segment by means of a carriage (56), so as to be movable in translation by relative to the anterior cross member (19).

13 - Chair according to one of claims 8 to 12, characterized in that the backrest (17) is adapted to the backrest by means of a slide (42) so as to be movable in translation relative to the seat (16). 14 - Chair according to one of claims 1 to 13, characterized in that the frame (1) is equipped with at least three wheels (3, 5).

15 - Chair according to claim 14, characterized in that at least one wheel (3) is motorized.