WO2002047513A1

WO2002047513A1 - Multiple-position armchair

Info

Publication number: WO2002047513A1
Application number: PCT/FR2001/003949
Authority: WO
Inventors: Gilles Galichet; Sylvie Galichet
Original assignee: Inov'hom
Priority date: 2000-12-12
Filing date: 2001-12-11
Publication date: 2002-06-20
Also published as: AU2002219288A1; FR2817720A1

Abstract

The invention concerns a multiple-position armchair comprising a frame (10), a seat (2), a back (1) and a leg-rest (3) mutually articulated. The articulation means (4, 6, 7, 30, 31, 32) and the control means (5) are designed to ensure co-ordinated movements of the seat, the back and the leg-rest in accordance with a predetermined continuous and unique law of displacement between a supine position (I) and an upright position (V), passing through a seated position (III). The articulation means (7, 73) of the back relative to the seat and the trajectory of the instantaneous geometrical axis (X) of articulation of the back relative to the seat are determined such that said axis (X) is permanently located at substantially constant distances respectively of the general plane of the set and the general plane of the back, so as to remain permanently substantially at the level of the user's hip joint (H).

Description

Multi-position armchair.

The present invention relates to a multi-position armchair, of the type making it possible to pass continuously and sequentially from a lying position to a standing position, and vice versa, passing through intermediate positions, in particular semi-seated, seated, semi-standing . Typically such an armchair comprises a seat, a backrest, and a leg rest, articulated between them and with respect to a frame resting on the ground.

Multi-position comfort chairs are already known, intended to ensure different comfort positions, generally between a lying position, or a semi-lying position, and a sitting position. Sometimes, for armchairs intended to provide assistance to persons with reduced mobility, the armchair is designed so as to be able, by means of complementary motor means, to accompany the movement of the user even in a standing position.

Furthermore, for uses typically in the medical field, articulated chairs are known, such as for example dental chairs, making it possible to support the patient in various positions between the sitting position and a semi-reclining position. Also in the medical field, there are articulated operating beds or tables so as to be able to pass from a lying position, the table then being perfectly flat, to a semi-sitting position. In this type of application, it is not primarily sought to provide a position of comfort for the seated or lying person, but a position most suitable for practicing medical operations or patient care. In particular, since there is no a priori need to ensure large amplitudes of movement while the patient is on the operating table or the chair, there is also no obvious need ensure continuity of comfort between the extreme positions of the operating table or chair.

In medical applications, it is therefore essentially sought to be able to place the patient support device, such as a bed, table or chair, in the most suitable position for the operation or operations to be carried out, the way in which the passage is carried out. from one position to another having less importance. This is why, it can moreover be privileged in such applications multi-command systems making it possible to ensure fine adjustments of the relative positions of the different parts of the device, without, however, requiring coordination of all movements. In the field of the comfort chair, the requirements are different since it is necessarily envisaged to be able to move from one position to another continuously or almost continuously.

In some cases, the seat and back positions can be controlled independently. However, it will be readily understood that all combinations of positions cannot be reasonably used, and consequently the adjustments conventionally allow the adjusted part of the seat to be positioned only within a limited range of positions. However, out of all the possible combinations, all the more numerous as there are several adjustable parts, most combinations can in fact prove to be uncomfortable, useless and even contrary to ergonomics, and can even contribute to an amplification of certain physical problems of the user, and this without the user being necessarily well aware of it at the start. These problems are particularly known and studied for example for car seats, or workstation arrangements, where ergonomic considerations lead to link the movements of the seat and back for example, to prevent combinations of uncomfortable or even harmful positions.

Furthermore, as soon as the chair must be able to provide a large amplitude pivot between the backrest and the seat, for example between a fully extended horizontal position both of the seat and of the backrest, in the extension one on the other, and a seated position with the back almost perpendicular to the seat, there is the problem of the articulation between these two elements. Indeed, if the position of the relative pivot axis of the backrest with respect to the seat is fixed and located substantially at the intersection of the mean planes of these elements, it follows that the passage from one position where the seat and the backrest are substantially aligned at a position where they are substantially perpendicular, for example from a lying position to a sitting position, is accompanied by a compression effect of the lower part of the user's trunk , that is to say of the lumbar region, which is somehow wedged between backrest and seat by a pincer effect. This effect results from the fact that, during such a movement of the chair, the movement of the user's body is also a rotation of the trunk, supported on the backrest, with respect to the thighs, supported on the seat, and that this rotation takes place along the pivot axis of the hips, called point "H" which is necessarily offset from the general planes of the seat and backrest, therefore relative to the relative pivot axis of these elements.

Conversely, when passing from a position where the seat and the back are substantially at right angles to a position where they are substantially aligned, it is a pulling effect which occurs, and which therefore tends to pull and discard the user's clothing, who is partially undressed after several these maneuvers.

Some ergonomic seats have already been proposed to solve this type of problem, but are only intended to bring the relative pivot axis of the backrest relative to the seat to the pivot axis of the user's hips, over limited strokes , for example to allow a height adjustment with variation of the inclination of the seat while maintaining the general vertical direction of the backrest, as shown in document US 5261723, or to ensure a coordination of the inclination of the seat with a voluntary modification of the inclination of the backrest as shown in document US 5,577,802.

No system known to date makes it possible to avoid the problems mentioned above in the case of an armchair as intended by the invention, intended to allow a continuous transition from a lying position to a standing position, while passing by a sitting position and all intermediate positions, and ensuring all the comfort and ergonomics desirable in all these positions.

The invention therefore aims to solve these problems. It aims in particular to propose an ergonomic and comfortable multi-position armchair and moreover preventing it from being placed in unwanted and physiologically harmful positions.

It also aims to ensure a smooth transition from one extreme position to the other, allowing in particular to bring the user into the standing position, still offering at this stage real support both to consolidate the balance of the user just when he arrives in the standing position, only to relieve him as much as possible of the increase in the support effort to be exerted by his legs when he regains the standing position.

With these objectives in view, the object of the invention is a multi-position armchair of the type comprising a frame, suitable for resting on the floor, a seat and a backrest pivoting with respect to the seat along a transverse pivot axis, the seat, the backrest and the frame being also connected between them by means of articulations and control means for adjusting their relative positions.

According to the invention, the chair is characterized in that the articulation means comprise: - a lifting frame articulated on a front part of the chassis along a transverse pivot axis and at the rear of which is articulated a lower part of the backrest, a connecting assembly connecting the rear end of the seat to a lower end point of the backrest, distant from the articulation of the backrest on the lifting frame, and the control means are arranged so as to ensure coordinated movements of the seat and the backrest according to a predetermined continuous and unique displacement law between a sitting position where the backrest is substantially vertical while the seat is substantially horizontal and either a lying position where the backrest and the seat are substantially in horizontal alignment, i.e. a standing position where the backrest and seat are substantially in vertical alignment, passing through intermediate positions. res, said articulation means as well as the trajectory of the instantaneous geometric axis of articulation of the backrest with respect to the seat being determined so that said instantaneous geometric axis is permanently located at substantially constant distances respectively from the general plan of the seat and the general plan of the backrest, so as to remain permanently substantially at the level of the hip joint of the user. The position of the instantaneous pivot axis between seat and backrest ensures a progressive variation in spacing between the rear of the seat and the bottom of the backrest, during a variation of the relative inclination between backrest and seat, this variation of spacing being able to avoid any compression or traction effect between the trunk and the thighs of the user. Thus, as will be better understood later, when switching from the lying position to the sitting position, this spacing increases, to avoid the aforementioned pincer effect, then decreases from the sitting position towards the standing position, to avoid the stripping effect also pre-mentioned.

These objectives can be achieved by the fact that, preferably, the lifting frame, the connection assembly, and the articulations between these elements and the seat and the backrest are arranged so that, when the backrest pivots relatively with respect to to the said lifting frame around the axis of the articulation, the backrest causes, by means of said connecting assembly, a pivoting of the seat such that the lower edge of the backrest and the rear edge of the seat move towards each other when the backrest and seat move to a position where they are substantially in alignment, and move away from each other when the backrest and seat move towards the sitting position.

According to a particular arrangement, the chair includes means for adjusting the position of the lower end point of the backrest relative to the backrest, in order to be able to adjust the position of the backrest relative to the seat according to the morphology of the user. .

Also, according to a very preferential arrangement, the armchair comprises a leg rest pivoting with respect to the seat along a transverse pivot axis, and the articulation means are arranged to ensure the coordinated movement of the legrest with respect to the seat and the backrest, according to a predetermined continuous and unique displacement law between a lying position where the backrest, the seat and the legrest are substantially in horizontal alignment and a standing position where the backrest, seat and legrest are substantially in vertical alignment, passing through intermediate positions including a seated position where the backrest and legrest are substantially vertical while the seat is substantially horizontal.

The law of single displacement therefore leads to the fact that, once the adjustment for adaptation to the user has been made, there is then only one possible combination of positions for the entire backrest, of the seat. and the legrest for a selected position of the seat or the backrest. All the positions being moreover studied so as to ensure optimal comfort for the user, it follows that this comfort is ensured automatically at all times when switching from any position to another. Furthermore, and in a particularly advantageous manner, the fact that there is only one possible displacement law for the three backrest elements, seat and legrest, makes it possible to use only one control member, for example an electric actuator, for controlling the whole of the chair, each position of the actuator determining in a assured manner the position of each of the elements of the chair. The handling of the chair is thus greatly simplified, and particularly easy in particular for a user with reduced mobility.

According to a preferred embodiment, the connection assembly comprises a return lever mounted pivoting towards the rear of the lifting frame and articulated moreover by an upper end on the rear of the seat, and a connecting rod the end point lower backrest at a lower end of said return lever.

According to a particular embodiment, the return lever is a V-shaped lever whose tip is pivotally mounted at the rear of the seat and which comprises a first arm articulated on the rear end of the lifting frame and a second arm on the end of which is connected the link.

According to a second embodiment, which will be better defined below, the connection assembly only comprises a link connecting the lower end point of the backrest to the rear of the seat.

According to another arrangement of the invention, the lifting frame comprising towards the rear a stop adapted to rest on a support bar secured to the chassis, as long as the chair is located in a position between the lying position and the position seated. According to yet another arrangement, the frame constitutes with the chassis, the backrest and a lower connecting bar connected to the backrest in its lower part, a deformable parallelogram ensuring the movement of the backrest between the sitting position and the standing position in a translation at during which the backrest remains substantially vertical. This translation is carried out along a substantially rectilinear or circular trajectory around an axis located substantially at the joint between the seat and the legrest, that is to say close to the knee joint.

According to other characteristics: the chair has a lower link bar, the rear end of which is articulated on the backrest in its lower part, and the front end of which is connected to the legrest so that the inclination of the legrest is controlled by the inclination of the backrest. the lower link bar is articulated on the one hand on a lower end of a rear case of the backrest, and on the other hand on a stirrup mounted pivoting at the front of the chassis, the stirrup being also connected by articulated arms respectively at the articulation between seat and legrest and at the rear face of said legrest - to adapt the relative position of the backrest to the seat according to the user, the lower end point of the backrest is located at the lower end of an adjustment rod fixed to a rear casing of the backrest so as to be adjustable in position. - The adjustment rod is fixed at its upper end to the rear folder casing by manual clamping means arranged so as to be able to adjust the vertical position of the upper end of the adjustment rod relative to the folder. - The control means comprise a jack mounted articulated between the chassis and a lower rear casing of the backrest. The actuator is preferably an electric actuator, which can be controlled by various remote control systems with or without wires, by a control integrated in one of the elements of the chair, by a control with manual, vocal, oral or foot control, etc.

- The chair comprises means for memorizing the position of the jack, for memorizing and simply finding a corresponding position of the backrest-seat-leg rest assembly.

Other characteristics and advantages will appear in the description which will be given of a multi-position chair according to the invention.

Reference is made to the accompanying drawings in which Figure 1 is a representation of the trajectory of the torso of a user, between the prone position and the standing position, Figures 2 to 6 illustrate in a decomposed manner the comfort positions successively obtained, Figures 7 and 8 illustrate the effect spacing between seat and back when moving into the sitting position, and reconciliation in the standing and lying positions,

- Figure 9 is a perspective view from 3/4 below of a preferred embodiment of the chair, Figure 10 is a perspective view of the chair from 3/4 above and cut along a longitudinal median plane, Figure 11 is a perspective view of the chair from the side and slightly from below and from the rear, also in section along a longitudinal median plane, - Figures 12 to 17 illustrate the successive positions of the chair between the lying position and the standing position, the figures 18 to 21 are similar views showing a possible alternative embodiment of the chair according to the invention.

Figure 1 shows the five representative positions of a user between the prone position (I) and the standing position (V), successively passing through the positions: semi-seated (II), seated (III) and semi-standing (IV). Line T illustrates the trajectory of the user's torso when passing through these different positions. It will be noted in particular that the transition from the lying position (I) to the sitting position (III) corresponds to a pivoting of the trunk relative to the thighs around the hip joint H, while the transition from the sitting position to the standing position (V) is a translation of the trunk along a substantially rectilinear and oblique trajectory. In fact, as will be seen later, the displacement of the backrest, which accompanies that of the trunk, takes place more precisely along a circular or substantially circular trajectory, having its center near the knee joint G.

Figures 2 to 6 illustrate the five positions mentioned above of the user's body. As an illustration, certain characteristic angles corresponding to so-called comfort positions have been indicated. Thus, in the semi-seated position of FIG. 3, the back being inclined at approximately 50 ° relative to the horizontal, the thighs are inclined by 14 °, the knees higher than the hips. From the seated position (Figure 4) to the standing position (Figure 6), the trunk is kept permanently tilted slightly back, for example 5 °. Starting from the sitting position where the thighs are still slightly inclined with respect to the horizontal, for example 3 °, one passes to the standing position by a progressive deployment of the legs, the thighs straightening up to find themselves substantially at the vertical in the standing position. In the drawings of FIGS. 7 and 8, the relative positions of the backrest 1 and of the seat 2 of the chair according to the invention are shown diagrammatically in the standing (V), seated (III) and lying (I) positions. . It can be seen that, according to the invention, the backrest and the seat move away from one another when the chair is in the sitting position. As can be clearly seen in the drawings, this spacing e makes it possible to maintain optimal and constant contact between on the one hand the thighs and the seat, and on the other hand between the back and the backrest, and this in all positions , thus ensuring the desired comfort. In relation to FIGS. 9 to 16, we will now describe a preferred embodiment of an armchair in accordance with the invention.

The chair comprises a frame 10 carrying by means of an articulation mechanism the backrest 1, the seat 2 and a leg rest 3.

The chassis 10 is produced for example from welded tubes, and comprises a base 101 on which a base is fixed, composed in the example represented by four swivel casters 102. At the front, the chassis comprises a vertical frame, constituted for example of two rigid feet 103 made of folded sheets, rigidly linked to the base 101. Towards the rear, the chassis also comprises a chassis stiffening bar, for example made up of a curved tube in the shape of a "U" 104, the branches extend substantially vertically to form grab bars 105, intended to support the load of the chair in certain positions, as will be seen later. The backrest 1 is mounted articulated, along a hinge axis A, by lower end tabs 11 on rear ends 41, bent upwards, of a lifting frame 4, itself articulated, towards the front, along a hinge axis B, on the upper ends of the front legs 103 of the chassis. The rear ends 41 of the lifting frame 4 carry stops 42, adapted to come to rest in vertical support on the upper ends 106 of the support bars 105 of the chassis. Furthermore, a control jack, for example an electric jack, 5 is mounted between the frame 10 and the backrest 1, the body 51 of the jack being articulated at E on the frame 10 near the front feet 103, and its rod being articulated at F on a casing 12 of a mechanism for adjusting its position, integral with the backrest 1 and at the rear thereof.

Thus, as long as the stops 42 of the armature of lifting remain in contact with the support bars 105, as will be seen later, the jack 5 makes it possible to directly control the pivoting of the backrest around the articulation A, and to adjust its position between a horizontal position, corresponding to the reclining position of the chair (I), and a vertical position corresponding to its sitting position (III).

A bracket 6 in the shape of an inverted U is pivotally mounted on the chassis 10 between the feet 103, the ends of the branches of the said U being articulated on the feet 103 along an axis K located in the lower part of the said feet. A double lower link bar 30, extending longitudinally under the seat, connects the lower end of the rear casing 12 of the backrest, on which it is articulated in D, to first upper tabs 61 of the stirrup 6 on which it is articulated along an axis C, at a distance from the articulation K of the stirrup on the chassis.

Towards the upper end of the stirrup 6, are also connected support arms from the front of the seat 2 and the legrest 3:

a first set of arms 31 connects the front edge of the seat 2 on which it is articulated in M to the upper legs 61 of the stirrup, to which it is connected by an articulation with an axis coincident with the axis C, or neighbor of the latter,

- A second arm 32 is also articulated by one end on a second leg 62 of the stirrup 6 along an axis L, close to the axis C or which can even be confused with it, and its other end is connected in N on l 'rear of the leg rest 3, substantially mid-height thereof.

It will be noted that the axis M is also coincident with the axis of articulation between the seat 2 and the legrest 3, or located in the immediate vicinity of the latter.

On the rear of the seat is mounted articulated according to an axis P a lever 7 with arms arranged in the shape of a "V". The ends of the two identical arms of a first set of arms 71 of this lever are also articulated in Q respectively on the curved rear ends 41 of the lifting frame 4, at a distance below the articulation A of the backrest on said frame 4. A second arm 72, located substantially in the median plane of the chair, is connected by a rod 73 to the lower end of an adjustment rod 13 linked to the rear casing 12 of the backrest. It will be noted that the V-shaped lever is a return lever essentially intended to control the movement of the rear of the seat relative to the lifting frame when it is pivotally controlled about the Q axis by the own pivoting of the backrest, via the link 73. The system of parts constituted by the lever 7 and the link 73 can therefore be replaced by any functionally equivalent system, based on systems of levers, cams, eccentrics, etc., since such systems make it possible to control the adequate movement of the seat relative to the backrest, or vice versa. It will be noted, however, that, in a manner specific to the invention, these means intended ultimately to obtain a relative pivoting of the backrest with respect to the seat around the virtual geometric axis corresponding to the point H of hip joint of the user, are entirely located at the rear of the seat and the backrest, and therefore have no space towards the front of the backrest or the top of the seat, where the actual relative pivot axis of the backrest is located relative to the seat.

The adjustment rod 13 has a longitudinal slot 14 in which is placed a pin 15 secured to the housing 12, and which can slide on this pin, and the upper end of the adjustment rod is secured to a rear wall 16 of the housing 12 by a manual tightening adjustment member, for example a knurled knob 17, the threaded rod of which passes through an oblong hole 18 extending in the longitudinal direction of the backrest. It is thus possible to adjust the position of the upper end of the adjustment rod 13 relative to the backrest, by adjusting its position relative to the oblong hole, and by locking it in the desired position by means of the knurled button 17. This adjustment allows thus to adjust, by acting on the angular position of the lever 7 by means of the rod 73, the relative position of the backrest with respect to the seat, therefore to modify the value of their spacing e, that is to say also to modify the position of the geometrical axis of relative pivoting, to adapt the seat to the morphology of the user.

We will now describe, in particular in connection with FIGS. 12 to 16, the movements of the various elements of the chair during the transition from the lying position to the standing position. The reverse movement will be evident from this, since the chair has only one law of displacement.

The overall displacements can be broken down into two successive phases, the first of which relates to the transition from the lying position to the sitting position, and the second the transition from the sitting position to the standing position.

In the lying position, shown in Figure 12, the backrest 1, the seat 2, and the legrest 3 are in horizontal alignment. The rod of the jack 5 is retracted as far as possible. The lifting frame 4 is supported by its stops 41 on the support bars 105 of the chassis. The backrest in the horizontal position keeps the link bar 30 pushed forward, which also keeps the stirrup 6 pivoted forward. Furthermore, the end of the adjustment rod 13 being also in an advanced position, it acts on the lever 7 in the direction of a pivoting of the latter around the axis Q, which keeps the axis P and therefore the rear of the seat in a retracted position, adjoining the bottom of the backrest. From the combination of the retracted position of the seat, driving the axis M and the top of the legrest 3, and the advanced position of the stirrup 6, it follows that the arms 31 and 32 are brought into a position pivoted backwards, leading to keep the legrest horizontal.

From this lying position, the output of the rod 52 of the jack 5 can be controlled, to bring the chair into the semi-seated position shown in Figures 13 and 14. The output of the rod of the jack has the effect of pushing the axis F rearward, pivoting the backrest around axis A. In doing so, the connecting bar 30 is pulled rearward by axis D, which rotates the stirrup 6 also towards the rear, and the lower end of the adjustment rod is also moved rearward, causing the lever 7 to pivot about the axis Q, still fixed relative to the chassis, and therefore a displacement of the axis P towards 1 front, in turn causing a displacement of the seat forward. The combination of the advance of the seat and the decline of the connecting bar 30 results in a pivoting forwards of the two arms 31, 32, having the effect of lifting the front of the seat in a first, and straighten the legrest 3, as can be seen in Figures 13 or 14. We can also see the gap that is generated between the rear of the seat and the bottom of the backrest.

By continuing this movement beyond the semi-seated position, the backrest continues to straighten, continuing to rotate the stirrup 6 backwards. As the seat also continues to be moved forward, it follows that the axis M of the front of the seat descends, ^" after going through a maximum altitude obtained in the semi-seated position, which has the effect of bringing the seat towards the horizontal, while the legrest arrives in a substantially vertical position at the same time as the backrest , as seen in Figure 15. The stirrup 6 then comes into abutment against a fixed stop 107 secured to the chassis.

The articulation axis C of the connecting bar 30 having then arrived in a maximum rear position, owing to the pivoted rearward position, as far as the stop, of the stirrup 6, visible in FIG. 15, all of the front part of the chair is then immobilized, namely the stirrup 6, the arms 31 and 32, the leg rest 3, and the hinge pin M of the front of the seat. The lifting frame 4, and the connecting bar 30 then form with the backrest and the chassis a deformable parallelogram ABCD, in which the points B and C are then fixed relative to the chassis. Under the effect of the continued output of the cylinder rod, this parallelogram begins to deform, by pivoting the lifting frame 4 around the axis B and the connecting bar 30 around the axis C , fixed with respect to the chassis as indicated above. This has in particular the effect of lifting the rear end of the lifting frame 4 and of releasing the stops 42 from their support on the upper ends of the support bars 105, as can be seen in FIG. 16 where the chair is shown. in the semi-upright position.

It will be noted incidentally that it is only in the seated position that the support of the stop 42 on the bars 105 and the support of the stirrup on the stops 107 are produced simultaneously. From the sitting position to the lying position, only the stops 42 are functional, and from the sitting position to the standing position, only the stops 107 are functional.

Furthermore, by continuing the movement from from the seated position, by the deformable parallelogram effect, and the axes C and D being fixed relative to the backrest, the latter moves parallel to itself, in other words remaining in the vertical position acquired during the arrival of the entire chair in the seated position. The pivoting of the lifting frame simultaneously causes the seat to pivot about its front articulation axis M, until it arrives in a vertical position, in vertical alignment with the legrest, simultaneously with the arrival of the folder also in this vertical alignment, corresponding to the standing position illustrated in Figure 17. It will be noted that the lever system 7 and link 73 simultaneously causes the rear edge of the seat to come together, that is to say its upper edge in this position, with the lower edge of the backrest.

It will also be noted that the pivoting of the backrest with respect to the seat takes place, both for the passage from the lying position to the sitting position, and for the passage from the sitting position to the standing position, along an immaterial instantaneous axis X permanently located at substantially constant distances from the backrest and the seat respectively, so as to be as close as possible to the position of the pivot axis of the user's hips H.

According to an arrangement not shown, but generally known per se, the legrest can be equipped with footrests, produced for example in the form of plates extending substantially perpendicular to the legrest and connected to the latter by a system of possibly sliding tubes to allow adjustment in position relative to said legrest. Beyond the sitting position towards the lying position, the footrests are raised above the ground, thus making it possible to move the chair on its casters. From the seated position and towards the standing position, the footrests come to rest on the ground, and in such a way that the front wheels of the chair are raised, the chair then resting only on the rear wheels and on the said footrests, which ensures its stability and avoids any risk of rolling or sliding on the ground during the lifting phase when the occupant is brought into a standing position.

Figures 18 to 21 schematically illustrate another embodiment of the invention.

In this embodiment, the front of the seat 2 and the top of the leg rest 3 are articulated together at a fixed point M 'on a front upper end of the chassis 10'.

This fixed point M ', or a neighboring fixed point on the chassis, also serves as an articulation for the lifting frame 4', on the curved rear end of which a back frame 12 'is articulated at A'. The ^' lower end of the backrest frame 12' carries a roller 121 which comes into contact with a cam track 106 secured to the rear part of the chassis, when the backrest is raised from the lying position under the thrust of the 5 'jack whose body is articulated on the chassis at E' and the rod articulated on the back frame at F '.

A set of bars and connecting rods controls the movement of the rear part of the seat 2 from the movement of the backrest 1. A connecting rod 75 is articulated on the rear of the seat in P ', and in R' on a set of bars linked to the back frame. This set of bars comprises a bar 76 connected to the lower end of the backrest frame at the level of the axis Q 'of the roller 121. Another bar 77 connects the connection point R' to the backrest frame to close to joint A '. A connecting bar 30 'is articulated on the back frame in its lower part in D', and connects this one on the one hand in C, or at a neighboring point, to an arm 31 'articulated in M', and on the other hand in L 'to an arm 32' whose end is connected to the legrest in N '. The front end of the connecting bar 30 ′ is provided with a roller 45 of axis C ′ which, when changing from the seated position to the standing position, as seen in FIGS. 20 and 21, is placed on a guide and support path 46 forcing the connecting bar 30 'to pivot about the axis c "of this roller 45, the lifting of the chair then being done by using the deformable parallelogram A'M'C'D' formed in particular by the link bar 30 ′ and the lifting frame 4 ′. In the phase of transition from the supine position to the seated position, the pivoting of the legrest is controlled by the arm 32 ′, driven by the movement towards the rear of the connecting bar 4 ′, itself caused by the pivoting of the backrest The invention is not limited to the embodiments which have been described above only by way of examples. the invention will find its application not only in the medical or paramedical field, where the total amplitude of its movements between the supine position and the standing position will be advantageously used, but also in applications where only part of the kinematics described previously as a whole will be commonly used, such as in the general field of the comfort seat or leisure, ergonomic, for furniture seats or seats usable in various means of transport, especially for the driver for example, such as in motor vehicles, planes or boats, public transport vehicles, etc.

Claims

1. Multi-position armchair with a frame

(10; 10 '), capable of resting on the ground, a seat (2) and a backrest (1) pivoting relative to the seat along a transverse pivot axis, the seat, the backrest and the chassis being by elsewhere connected to each other by articulation means and control means for adjusting their relative positions, characterized in that the articulation means comprise: - a lifting frame (4; 4 ') articulated on a front part of the chassis along a transverse pivot axis (B, M ') and at the rear of which is articulated (axis A) a lower part of the backrest (1), a connection assembly (7, 73; 75) connecting the rear end of the seat at a point (R; R ') of the lower end of the backrest, distant from the articulation (A) of the backrest on the lifting frame, and the control means (5; 5') are arranged so as to ensure coordinated movements of the seat and backrest according to a predetermined continuous and unique displacement law between a sitting position (III) where the back is substantially vertical while the seat is substantially horizontal and either a lying position (I) where the back and the seat are substantially in horizontal alignment, or a standing position (V) where the backrest and seat are substantially in vertical alignment, passing through intermediate positions, the said means of articulation as well as the trajectory of the instantaneous geometric axis (X) of articulation of the backrest with respect to the seat being determined so that said instantaneous geometric axis (X) is permanently located at substantially constant distances respectively from the general plane of the seat and from the general plane of the backrest, so as to remain permanently substantially at the level of the hip joint (H) of the user.

2. Chair according to claim 1, characterized in that the lifting frame, the connection assembly, and the articulations between these elements and the seat and the backrest are arranged so that when the backrest pivots relatively relative at said lifting frame around the axis of the articulation (A), the backrest causes, by means of said connecting assembly, a pivoting of the seat such that the lower edge of the backrest and the rear edge of the seat approach each other when the backrest and the seat move to a position (I, V) where they are substantially in alignment, and move away from each other when the backrest and seat move to the sitting position (III).

3. Chair according to claim 1, characterized in that the connecting assembly comprises a return lever (7) pivotally mounted (in Q) towards the rear of the lifting frame (4) and also articulated by a upper end (in P) on the rear of the seat, and a link (73) connecting the point (R) of the lower end of the backrest to a lower end of said return lever.

4. Chair according to claim 3, characterized in that the return lever is a V-shaped lever (7) whose tip is pivotally mounted at the rear of the seat (2) and which comprises a first arm (71) articulated on the rear end of the lifting frame (4) and a second arm (72) on the end of which is connected the link (73).

Armchair according to claim 1, characterized in that the connection assembly comprises a link (75) connecting the point (R ') of the lower end of the back to the rear of the seat.

6. Chair according to claim 1, characterized in that the lifting frame (4; 4 ') constitutes with the chassis, the backrest and a lower connecting bar

(30; 30 ') connected to the backrest in its lower part, a deformable parallelogram (ABCD; A'M'C'D') ensuring the movement of the backrest between the sitting position and the standing position in a translation during which the backrest remains substantially vertical.

7. Chair according to claim 1, characterized in that the lifting frame (4) comprises rearward a stop (42) adapted to rest on a support bar (105) secured to the frame, as the chair is located in a position between the lying position and the sitting position.

8. Chair according to claim 1, characterized in that it comprises a leg rest (3) pivoting relative to the seat along a transverse pivot axis (M; M '), and the articulation means are arranged so as to ensure the coordinated movement of the legrest with respect to the seat and the backrest, according to a predetermined continuous and unique displacement law between a lying position (I) where the backrest, the seat and the legrest are substantially in horizontal alignment and a standing position (V) where the back, the seat and the legrest are substantially in vertical alignment, passing through intermediate positions including a seated position (III) where the back and the legrest are substantially vertical while the seat is substantially horizontal.

9. Chair according to claim 8, characterized in that it comprises a lower connecting bar (30; 30 ') whose rear end is articulated on the backrest in its lower part, and whose front end is connected to the legrest so that the inclination of the legrest is controlled by the inclination of the backrest.

10. Armchair according to claim 9, characterized in that the lower link bar (30) is articulated on the one hand on a lower end of a rear casing (12) of the backrest, and on the other hand on a stirrup ( 6) pivotally mounted at the front of the chassis, the stirrup (6) also being connected by articulated arms (31, 32) respectively to the articulation (M) between seat (2) and legrest (3) and on the back of said leg rest.

11. Armchair according to claim 1, characterized in that it comprises means for adjusting the position of the point (R; R ') of the lower end of the backrest with respect to the backrest, in order to be able to adjust the position of the backrest with respect to at the seat according to the morphology of the user.

12. Chair according to claim 11, characterized in that the point (R; R ') of the lower end of the backrest is located at the lower end of an adjustment rod (13) fixed on a rear casing (12) backrest adjustable in position.

13. Armchair according to claim 12, characterized in that the adjustment rod (13) is fixed at its upper end to the rear casing (12) of the backrest by manual clamping means (17) arranged so as to be able to adjust the vertical position of the upper end of the adjustment rod relative to the backrest.

14. Chair according to claim 1, characterized in that the control means comprise a jack, in particular an electric jack (5), mounted articulated between the frame (10) and a lower rear casing (12) of the backrest.

15. Chair according to claim 10, characterized in that it comprises means for memorizing the position of the jack.