EP0699067B1 - Lifting device for a stand-up wheelchair and wheelchair using same - Google Patents

Abstract

PCT No. PCT/FR95/00330 Sec. 371 Date Mar. 25, 1996 Sec. 102(e) Date Mar. 25, 1996 PCT Filed Mar. 17, 1995 PCT Pub. No. WO95/25497 PCT Pub. Date Sep. 28, 1995A wheelchair having a lifting device wherein the seat and the footrest are independent from each other and are mounted on the top ends of two deformable quadrilaterals extending upwards from the chassis and sharing a common moving portion, and wherein the raising and lowering control devices comprise a drive member interposed between the chassis and one of the moving members of one of the quadrilaterals, and suitable for controlling the displacement of said quadrilaterals between a stable folded state and a stable unfolded state.

Description

TECHNICAL AREA

The present invention relates to wheelchairs used by the disabled and invalids and it applies, indifferently, to folding wheelchairs or not.

There is no question that wheelchairs have provided an opportunity to mobility for the disabled and disabled. These wheelchairs have, however, several drawbacks due to the fact that users can only occupy one sitting position, moreover, generally maintained for relatively long periods long. To try to remedy the disadvantages of this one possibility of use, different proposals have been made for such armchairs are made vertical, in order to keep the user in a substantially upright position.

PRIOR ART

As a general rule, the proposals made involve a structure articulated comprising a backrest, a seat and a footrest. Such a structure is mounted articulated generally by the seat on a horizontal front axis and perpendicular to the vertical plane of symmetry of the chassis. A driving means is interposed between the chassis and the structure to allow raising or lowering of the latter, thus able to occupy a folded position called sitting and a unfolded position called verticalized. The driving organ can be indifferently to manual, electric or other control.

To illustrate this prior technique, it is possible to cite, among others, FR-A-2 020 453, DE-A-26 25 045 or even FR-A-2 529 456

These various proposals certainly meet the objective of targeted verticalization and, in this sense, have brought an undeniable well-being to users.

The structural propositions which have been formulated by the prior art generally rely on the articulation of the articulated structure on a frontal axis horizontal and perpendicular to the vertical plane of symmetry of the chassis and bearing on the latter.

Such an organization has the effect, in the verticalization function, of transfer the articulated structure and the upright user to the anterior part of the wheelchair resulting in increased load on the wheels front wheels and a reduction in that of the rear wheels.

Such a consequence introduces a factor of instability, since the support polygon is not loaded evenly. It's here this is why, as a rule, additional support points are designed to stabilize the chair in the vertical position of the structure articulated. Such additional support points are frequently, not to say always, constituted by castors, skates, crutches or even by heels which are provided for construction in the extension of the footrest, so as to rest on the ground in the verticalized state of the articulated structure.

If such a proposition, in the general sense, makes it possible to confer a factor of stability and security for users, however, it poses a insurmountable problem when it is necessary to take into account the will to make wheelchairs, mobile, even in the verticalized state of the articulated structure. Such a trend corresponds to the desire of users to be able to recover, by such a means, a perfectly understandable form of life and autonomy.

Being able to reconcile such a wish with current technology seems incompatible with the search for great stability and, where appropriate, good handling.

In an attempt to remedy such a double requirement, proposals for different construction were made by the prior art. It was thus proposed, for example as illustrated by US Patent 3,907,051, to place the means of motorization in a rear box, so as to ballast the chair rolling to lower the center of gravity and balance the frontal overload which is established in the vertical position.

Such a proposal must certainly make it possible to respond in part to the problems of stability and security, but does not appear to be usable in all the configurations and with all the energies likely to be implemented to motorize the wheelchair.

Furthermore, such a proposal appears hardly compatible, with the wish to have a wheelchair that is always foldable to allow its easy transport, especially in a motor vehicle.

The prior art knows a different proposition by demand WO 82-01314 which recommends mounting on the chassis of the wheelchair a articulated structure which, when moving to the vertical position, experiences a back-displacement relative having the effect of placing the entire structure and the user substantially in alignment with the vertical axis passing through the center of the support polygon that constitutes or defines the chassis.

In this way, the general vertical load is distributed relative to the support polygon and gives it a certain stability making it possible to envisage the motorization and movement of the wheelchair, even in this state of verticalization.

However, examination of the proposal shows that the technology proposed by application WO 82-01314, is relatively complicated and highlights work a high number of points of articulation between the different elements of the articulated structure and numerous linkages connecting the structure to frame.

These numerous articulation links weaken the construction, weigh down assembly and require constant maintenance to avoid local malfunction any result in a defective folding or unfolding, likely to lead to accidents.

In addition, a large part of these joints are placed in front of the chair and especially in a frontal area to the seat with the effect of hindering access to the latter for a disabled or disabled person.

In addition, automatically causing the back-displacement of the articulated structure involves moving the footrest in the same direction, by a frontal position corresponding to a seated state in a reclined position corresponding to a verticalized state.

This displacement in the antero-posterior direction during the two movements involves leaving sufficient passage clearance for the footrest and poses a hardly soluble adaptation problem on the wheel chassis anterior, pivoting and directional, generally of smaller diameter than the load-bearing rear wheels, as is most commonly adopted for wheel chairs.

This subjection complicates the manufacture of the armchair, as well as the realization of the latter in a space gauge in particular transverse, compatible with different areas of use, such as domestic use, for which a passage between the door frame jambs of standard doors must be made possible.

The number of joints and the large number of connecting rods also have for incidence of considerably weighing down the equipped wheelchair which becomes less easy to handle, while requiring more physical expenditure from the user important when the movement of the wheelchair is not ensured or assisted by a on-board motorization.

The present invention aims to remedy the above drawbacks by proposing new means of connection between an articulated structure and an armchair frame rolling verticalizer, such means, while allowing verticalization, also allowing to trigger, automatically and simultaneously to the phase of verticalization, a retro-displacement of the articulated structure to center the load verticalized with respect to the support polygon and thus give the chair placed in such a state of use, stability and security allowing mobility and manual or motorized movement, without any risk for the subject verticalized.

Another object of the invention is to provide support means and simple, reliable, light and inexpensive, so as to make possible adaptation in the best conditions, without weighing it down considerably the chair and thus make it possible, if necessary, an adaptation on folding armchairs.

STATEMENT OF THE INVENTION

• l'assise et le repose-pieds ne présentent aucune articulation directe l'un avec l'autre, et sont montés sur les extrémités supérieures de deux quadrilatères déformables, s'élevant à partir du châssis et possédant une partie mobile commune,
• les moyens de commande en élévation-abaissement comprennent un organe moteur interposé entre le châssis et l'un des organes mobiles de l'un des quadrilatères et apte à commander le déplacement desdits quadrilatères entre un état stable replié correspondant à une position dite assise de la structure et un état stable déplié correspondant à une position dite de verticalisation de la structure dans laquelle la masse que représente cette dernière est sensiblement centrée par rapport au polygone d'appui.

To achieve the above objectives, the lifting device for the verticalizing wheelchair is characterized in that

• the seat and the footrest have no direct articulation with each other, and are mounted on the upper ends of two deformable quadrilaterals, rising from the chassis and having a common mobile part,
• the lifting-lowering control means comprise a motor member interposed between the chassis and one of the movable members of one of the quadrilaterals and capable of controlling the movement of said quadrilaterals between a folded stable state corresponding to a so-called sitting position of the structure and an unfolded stable state corresponding to a so-called vertical position of the structure in which the mass represented by the latter is substantially centered with respect to the support polygon.

The invention also relates to a stand-up wheelchair comprising a articulated structure linked to the chassis by the above means.

Various other characteristics will emerge from the description given below in reference to the accompanying drawings which show, by way of nonlimiting examples, embodiments of the subject of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 is a schematic side elevation of a chair according to the invention.

Figure 2 is a front view, taken along line II-II of Figure 1 .

Figures 3 and 4 are views similar to Figure 1 , illustrating the chair in two characteristic positions.

Figure 5 is a front view similar to Figure 2 , but illustrating an alternative embodiment.

BEST WAY TO REALIZE THE INVENTION

FIGS. 1 and 2 schematically show a wheelchair 1 comprising a chassis 2 constituted by a lower frame 3 , for example formed by longitudinal members 4 joined by crosspieces 5 and 6 . It goes without saying that this embodiment is given only by way of example and schematically, for the sole purpose of lightening the representation while allowing the understanding of the object of the invention. Thus, the frame 2 is provided, usually in a known manner, wheels 7 generally carriers, and main drive and steering wheels 8, steerable by means of pivots 9. The wheels 8 are generally, but not necessarily, placed at the front part of the chassis 2 , while the carrying wheels 7 occupy the rear part. The wheels 7 and 8 define, by the points of contact with the ground S , a support or support polygon through the center of which passes a vertical axis x-x ' . The wheels 7 are mounted on the chassis 2 by means of bearings 10 and can advantageously be associated with motor members for reversible rotation drive 11 , such as one or more electric motors capable of being powered from a source 12 on board and arranged on a console 13 placed between uprights 14 .

The chassis 2 conventionally supports an articulated structure comprising a seat 20 , a backrest 21 and a footrest 22 . In a known manner, the articulated structure is organized to be able to occupy a stable, folded state, corresponding to a so-called sitting position, as illustrated in FIG. 1 and a stable, unfolded state, corresponding to a verticalization position, such as illustrated in Figure 4 . In these two positions and by means known in the art and not shown, the articulated structure is able to support a disabled or disabled person in a seated position and in a vertical position respectively.

According to the invention, the articulated structure is organized so that the seat 20 is carried by the frame 2 by means of an articulation means 23 in the form of a deformable quadrilateral, such means being for example organized in two side assemblies 24 . Each assembly includes a rear articulated part or link 25 and a front articulated part or link 26 which are respectively mounted by pins 27 and 28 on the rear uprights 14 and on the side members 4 . The upper ends of the articulated parts or connecting rods 25 or 26 carry the seat 20 by means of articulation pins 29 and 30 which are respectively placed substantially in the middle part of the underside of the seat 20 and at the front part of the latter. In the folded state, the part 25 extends from the uprights 14 forward, in a substantially horizontal direction, while the front articulated part 26 also extends forward but in an upward inclination from chassis 2 .

The backrest 21 is mounted, according to the invention, by a hinge pin 31 on the rear part of the seat 20 and is linked to the latter by a hinge means 32 in the form of a deformable quadrilateral. The means 32 comprises a movable part which is common to the deformable quadrilateral 23 .

The means 32 is for example constituted by an extension 21a extending downward from the backrest 21 and on which is articulated, by an axis 33 , a movable part 34 , such as one or two links linked by an axis 35 at the rear part or parts 25 constituting the deformable quadrilateral 23 .

The mobile part 34 can also be organized into two lateral assemblies in the same way as the assemblies 24 .

The footrest 22 is preferably constituted by two legs 40 each provided at the base of a sole 41 . The two legs 40 are independent and devoid of articulation with the seat 20 and are carried by the chassis 2 by means of an articulation means 42 , of the deformable quadrilateral type, preferably also organized like the other quadrilaterals. in the form of two side assemblies. Each lateral assembly comprises a front part 43 articulated by an axis 44 on the chassis 2 and carrying the corresponding leg by an upper articulation axis 45 . Each lateral assembly also involves, for the constitution of the deformable quadrilateral, a common element with the deformable quadrilateral 23 , such a common element being constituted by the front part 26 which is, in such a case, located posterior to the front part 42 . To assume this function, the front part 26 is provided, below its point of articulation 30 with the seat 20 , of an extension 46 on which the leg 40 is mounted by means of a hinge pin. 47 .

The front part 43 of each deformable quadrilateral 42 extends forwardly in a rising inclination between the frame 2 and the leg 40 .

As shown in FIG. 1 , the deformable quadrilateral system 23 is defined by the articulation points 27 , 28 , 29 and 30 . The deformable quadrilateral articulation system 32 is defined by the articulation points 29 , 31 , 33 and 35 . The articulation system based on a deformable quadrilateral 42 is defined by the articulation points 28 , 44, 45 and 47 .

According to the invention, provision is made to provide the lifting device described above with a drive member 50 making it possible to pass the articulated structure from the position according to FIG. 1 to the position according to FIG. 4 and vice versa. Such a drive member 50 may be constituted by a manually controlled mechanism or, preferably, by an energy transformer, of the electric jack type, capable of being supplied from the source 12 , in particular by means of a manipulator 51 accessible, for example on one of the removable or orientable armrests 52 , fitted to the backrest 21 or the seat 20 . The drive member 50 is interposed between the chassis 2 and one of the mobile elements of one of the deformable quadrilaterals and, preferably, that 23 specific to the seat 20 . In an appropriate example illustrated by FIG. 1 , the motor member 50 is constituted by an electric actuator whose base is adapted to the chassis 2 and whose rod is, for example, articulated by an axis 53 on a crosspiece connecting the parts 25 of the two side assemblies 24 .

In the case of adaptation of a manually controlled drive member 50 , provision may be made to associate elastic compensators, such as gas cylinders, making it possible to relieve the load, in particular, during the unfolding of the articulated structure for to pass from the state according to figure 1 to the verticalized state according to figure 4 .

Although this is not shown, the frame 2 can be organized to show one or more stops 60 reserving a support for the articulated structure in position or in the folded state, cooperating for example directly or indirectly with the seat 20 and / or one of the appropriate deformable quadrilaterals.

In the state according to Figure 1 , the articulated structure is in the folded position in a position such that the seat 20 is substantially horizontal and that the footrest 22 is located just in front of the front part of the chassis and the plane transverse of the articulation pivots of the steered wheels 8 .

When it is desired to control the change of state of the articulated structure to make it pass into a verticalization state, the motor member 50 is controlled, for example to ensure its extension stroke, so that it tends to lift the articulated elements 25 constituting the deformable quadrilateral 23 specific to the seat 20 . The articulated elements 25 are thus required to pivot in the direction of the arrow f ₁ (fig. 3) on the axes 27 and cause the displacement of the axis 29 according to a circular trajectory T ₁ having for its center the axis 29 and for radius the length of the elements 25 .

The movement of the axis 29 leads in the same direction to the seat 20 , the hinge axis 30 of which is displaced along a circular trajectory T ₂ having the axis 28 as its center and the length of the front part 26 as its radius. The constructive characteristics of the deformable quadrilateral 23 mean that the curves T ₁ and T ₂ intersect at a point O ₁ , as illustrated in FIG. 3 , so that the seat moved backwards is simultaneously subjected to relative pivoting in the direction of the arrow f ₂ .

Simultaneously, the pivoting of the seat 20 causes the upward movement of the axis 31 which subjects the backrest 21 to a relative movement relative to the seat, although remaining by itself substantially in the same inclination. Such a characteristic is provided by the structure of the deformable quadrilateral 32 .

The displacement along the curve T ₂ of the point 30 causes the displacement along the curve T ₃ of the articulation point 47 of the deformable quadrilateral 42 , this trajectory T ₃ having as its center the articulation point 28 and as its radius the link portion 26 between this point and axis 47 . By means of the legs 40 , the articulation points 45 are displaced along a circular path T ₄ , having the axis 44 for center and the length of the front elements 42 for radius.

This characteristic makes that, in the intermediate phase and concomitantly with the movement in the direction of the arrow f ₂ of the seat 20 , the footrest 22 is raised and back-displaced, as it appears in FIG. 3 . The measurement of elevation is conferred by the constructive characteristics of the deformable quadrilateral 42 , in such a way that, when the flanges 41 overhang the horizontal casing of pivoting of the front wheels 8 , with their initial inclination, they are situated at a height from the ground S greater than the diameter of the latter. In this way, the backrest displacement of the footrest 22 can be carried out freely whatever the orientation of the front steering wheels 8 .

The characteristics of the deformable quadrilaterals are chosen by construction so that, after the displacement of the drive member 50 on its active stroke, the seat 20 and the backrest 21 are substantially placed in alignment at a slight inclination, while the feet 22 is located by back-displacement included inside the support polygon defined by the wheels 7 and 8 . In this so-called verticalization state, as shown in FIG. 4 , it appears that the articulated structure is distributed as a whole on either side of the vertical axis x-x ' , so that the load or mass that it represents alone and that which the verticalized subject constitutes are perpendicular to said vertical axis x-x ' and substantially at the center of the support polygon to give the chair brought into such a configuration, a stable state allowing movement through the wheels.

The constructive characteristic of the support and articulation means based on three deformable quadrilaterals has the characteristic of causing the relative displacement of the backrest, the seat and the footrest, along the paths T ₁ , T ₂ , T ₃ and T ₄ which are directed towards the rear part of the chair and thus generate a retro-displacement of the articulated structure to bring the latter from the sitting position with an anterior tendency to a vertical position substantially centered on the axis x-x ' .

Furthermore, as appears from the comparison of Figures 1, 3 and 4, the means according to the invention make it possible to significantly reduce the bulk in the anteroposterior plane of the chair in a vertical position and to give it in this state a compactness favoring the evolutions.

A reverse operation to what has just been described is established when the member 50 is controlled to bring the articulated structure from the vertical position to the seated position illustrated in FIG. 1 .

FIG. 5 shows an alternative embodiment in which the deformable quadrilaterals are no longer organized in lateral assemblies such as 24 , but in the form of a column being grouped on either side of the anteroposterior plane of vertical symmetry P-P ' .

INDUSTRIAL APPLICATION

The invention finds a particularly interesting industrial application in the standing chairs which, moreover, offer a possibility of folding along a vertical, longitudinal plane of symmetry, so as to reduce it congestion in the transport phases, in particular in the automobile.

The invention is not limited to the examples described and shown since various modifications can be made without departing from its scope, as defined by the claims.

Claims (9)

1. A lift device for a stand-up wheelchair, the wheelchair being of the type comprising a chassis (2) provided with wheels (7, 8) defining a support polygon and supporting a hinged structure comprising a seat (20), a footrest (22), and a back (21), the device comprising means for supporting and hinging the structure on the chassis and means for controlling raising and lowering of said structure relative to the chassis,
      characterized in that:

   the seat and the footrest have no direct hinges between each other and are mounted on the top ends of two deformable quadrilaterals (23, 42) extending upwards from the chassis and possessing a moving portion in common (26); and

   the means (50) for controlling raising and lowering comprise a drive member interposed between the chassis and one of the moving members of one of the quadrilaterals, and suitable for causing said quadrilaterals to move between a stable, folded state corresponding to a "sitting" position for the structure and a stable, unfolded state corresponding to a "standing" position for the structure in which the mass represented by the structure is substantially centered relative to the support polygon.
2. A lifting device according to claim 1, characterized in that the structure comprises a footrest (22), a seat (20), and a back (21) hinged at its base on the back portion of the seat and connected via a deformable quadrilateral (32) to the deformable quadrilateral of the seat and sharing a common moving portion (25) therewith.
3. A lifting device according to claim 1 or 2, characterized in that the hinged structure is mounted on the chassis by deformable quadrilaterals which are organized as two lateral linkages (24).
4. A lifting device according to claim 1 or 2, characterized in that the hinged structure is mounted on the chassis by deformable quadrilaterals organized in the form of a column.
5. A lifting device according to any one of claims 1 to 4, characterized in that the structure comprises a seat (20) which is hinged at its front end and substantially in its middle respectively on the top ends of front and back moving portions (25, 26) constituting the quadrilaterals and connected to the bottom portion (3) and to the back portion (14) of the chassis.
6. A lifting device according to any one of claims 1 to 5, characterized in that the structure comprises a footrest (22) which is hinged on the one hand via a rear portion on a said front moving portion (26) of the deformable quadrilateral (23) and on the other hand in front of said rear portion on a front moving portion (43) constituting the deformable quadrilateral (42) itself hinged on the bottom portion of the chassis.
7. A lifting device according to any one of claims 1 to 6, characterized in that the drive member (50) is constituted by an energy transformer interposed between the chassis (2) and the quadrilateral (23) belonging to the seat.
8. A lifting device according to any one of claims 1 to 6, characterized in that the drive member (50) is constituted by manually-driven means associated with at least one resilient compensator.
9. A stand-up wheelchair including a hinged structure connected to its chassis by a lifting device according to any one of claims 1 to 8.

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