EP1931295A1 - Folding wheelchair chassis and folding wheelchair - Google Patents

Abstract

The invention relates to a folding wheelchair chassis and a folding wheelchair. The two sides (1 and 2) of the chassis consist of rigid rectangular frames comprising upper (3) and lower (4) horizontal bars and rear (6) and front (5) posts. The aforementioned components are maintained in parallel adjustable positions by a pair of cross-pieces (8). The rear end of each cross-piece pivots in relation to the post (6) of one of the sides by means of a bush (7) and the front end of each cross-piece is connected by means of a sliding coupling (9, 10, 11) to the horizontal bars (3 and 4) of the other side. The two cross-pieces (8) are articulated to one another by a pivot device (12).

Description

 Foldable wheelchair frame and foldable wheelchair

The majority of folding wheelchairs that are known generally comprise a frame with one or more pairs of braces articulated on one another forming a parallelogram system deformable in a vertical plane.

This kind of chairs has several disadvantages. In particular, when the chair is folded, the size of the braces, which depending on the size of the chair exceed above the level of the armrests, prevents the folding of the backrest, which does not facilitate the transport of the chair and requires packaging of big size. On the other hand, the difficulties of operating the chassis constitute an obstacle to its use in certain circumstances. In particular, when folding the chair, this type of frame does not allow its sides to remain parallel. Although the flanks are found parallel at the end of folding, they are not during folding, which implies a tension of the backrest lining and a hard spot during the folding or unfolding phases of the chair.

This type of deformable parallelogram chassis comprises moving parts, some of which are only occasionally in contact with each other. The contacting of these parts during closing or opening movements of the chair can sometimes cause rapid wear or deterioration of the object, whose life can be shortened. In addition, it is not possible to design a production of standardized chassis, usable indifferently for different widths of chair.

Wheelchairs with horizontally articulated and articulated sets of crosspieces are also known. around vertical axes. Such a chair is for example described in US Patent 4,648,619.

However, as for vertical cross chairs, these chairs have defects in execution, in particular the means for transmitting forces between the braces and flanks cause parasitic forces or generate a lack of overall rigidity of the chair.

The object of the present invention is to design a principle of realization of foldable wheelchairs frame allowing the manufacture and the marketing of foldable wheelchairs not having the defects mentioned above.

More particularly, the present invention relates to a foldable wheelchair frame as defined in claim 1. It also relates to a foldable wheelchair as defined in claim 10.

Other important features of the invention are defined in the dependent claims.

The peculiarities and advantages of these various possible embodiments within the scope of the invention will emerge from the following description and comments, describing several embodiments by way of example only with reference to the drawings.

- fig. 1 is a simplified perspective view of a first embodiment of the frame according to the invention, in the unfolded position,

- figs. 2 and 3 are plan views from above of the frame of FIG. 1, in respectively semi-folded and fully folded positions, - figs. 4, 5, and 6 are perspective views showing a wheelchair using the frame of FIGS. 1 to 3, in positions respectively open, half folded and fully folded,

- fig. 7A is a side elevational view of the flanks and crosspieces in a second embodiment of the subject of the invention, the chassis being open (unfolded chair),

- figs. 7B and 7C are perspective views of the frame and part of a sidewall with the pivoting joint of a spider, in a variant of the second embodiment, the chassis being partially open,

- figs. 8A and 8B are partial perspective views, similar to FIG. 7C, showing the sliding hinge link between a flank and a spider in the second embodiment and in another variant of this second embodiment,

- fig. 9 is a perspective view of a wheelchair structure with a third embodiment of the frame according to the invention in unfolded position,

- fig. 10 is a perspective view of a wheelchair using the first embodiment of the frame according to the invention with a locking system with two links articulated under the seat, the chair being in the half-folded position,

- fig. 11 is a schematic perspective view showing in semi-folded position the frame according to the first embodiment with a locking system with links, articulated between the sliding connection of the crosspieces and an amount of the flanks, - AT -

- fig. 12 illustrates an example of possible packaging for the transport of a wheelchair according to the present invention, and

- fig. 13 is a detail view of the crossbar device of the chair of FIG. 9.

The simplified chassis shown in FIGS. 1 to 3 is a robust and rigid construction using prefabricated elements easy to work. Each of the flanks 1 and 2 consists of rigid bars, for example metal, especially steel or light metal tubes assembled preferably by welding, although other known assembly methods can also be envisaged. The upper 3 and lower 4 bars of each side are rigidly connected to the front and rear uprights 5, 6, and intended to work in a horizontal position. The rear uprights 6 serve as guiding bushings or connecting yokes 7 pivoting on them and each of which is fixed the rear end of a spider 8 whose front end is secured to a movable sliding linkage 9 along the other side. The braces 8 and their connection devices with socket 7 at one end and 9 at the other end represent an essential part of the frame described. Each upright 9 is connected, at its upper and lower ends, by pivoting articulations of vertical axis with two slides 10 and 11 being able to move along the upper and lower bars 4 of the sidewalls 1 and 2. This gives the structure of fig. 1 which we understand that it can be more or less folded as shown in Figs. 2 and 3 by simply sliding the elements 10 and 11 linked by pivoting to the uprights 9 on the bars 3 and 4. The assembly is such that the braces 8 pass one above the other. They are preferably connected by a pivoting device 12 of vertical axis as shown in FIGS. 1 and 2, the latter representing the chassis in a semi-folded position, while FIG. 3 shows a fully folded position reachable by an adequate conformation of the device 12, for example with extractable pivot rod. The structures of the various elements described may be chosen differently depending on the intended use. In particular, the slides 10, 11 are not necessarily tubular, they can also be trough-shaped. It is also noted that the device 12 can be arranged externally to the bars or tubes of the braces 8, which avoids weakening their rigidity by holes.

The use of the frame of FIGS. 1 to 3 for the construction of a wheelchair is illustrated in FIGS. 4 to 6. The structural elements 3, 4, 5 and 6 of the flanks 1 and 2 and the connecting uprights 9 of the crosspieces 8 are recognized. A rigid seat plate 13, with a central longitudinal articulation, fixed by its longitudinal edges on the bars 3 of the flanks 1 and 2, keeps the braces 8 in the spread positions when the chair is unfolded as shown in FIG. 4, thus ensuring the locking of the chair in the unfolded position. Of course, a security locking device of the seat plate in the locked position can be added. The longitudinal joint may take the form of a system of hinges placed under the elements of the seat plate. The armrests 14 and the side walls 15 are rigidly fixed to the bars 3 while the two parallel handles 16 are mounted at the rear end of the bars 3 beyond the uprights 6, so as to allow their folding in the folded or unfolded position. Between the risers of the handles 16, one can naturally provide the installation of a flexible backrest, for example textile, or rigid with a possibility of folding when the wheelchair in the folded position. The steerable front wheels 17 and the rear carrying wheels 18 are mounted via their hubs on brackets 19 and 20 which are attached to appropriate elements integral with the frames of the flanks 1 and 2. It can be seen that the consoles 19 of the front wheels comprise forks pivoting on vertical axes at the front of the uprights 5. A footrest 21 is furthermore provided on each flank 1 and 2 so as to fold forward of the wheels 17 when the chair is in the unfolded position (FIG 4). An important advantage of the described construction is the ease and security offered for the transition from the unfolded position to a semi-folded position, for example for crossing a path constriction, or to the fully folded position, for example for boarding in another vehicle or for a simple trip.

Figs. 7A to 8B show a second embodiment of the frame according to the invention, given as an example in several variants.

Flanks 22 and 23 are here rigid assemblies that can be assembled from prefabricated by welding, gluing or any other technique, or molded in one piece. They comprise an upper bar 24 and a lower bar 25 connected to the front by an upright 26 with spacer. Braces 30, 31, arranged as in the first embodiment, provide the connection between the flanks 22 and 23 and allow to gradually change the arrangement of the frame between a fully open position as in FIG. 7A and a semi open position as in FIG. 7B to a closed position as shown in the example of FIG. 3. The uprights 26 could serve as connection to load wheels (not shown). At the rear, the frames that constitute the flanks 22 and 23 are closed, in the variant according to FIG. 7A, by cylindrical bars 27 connecting the bars 24 and 25 and, in the variant according to FIG. 7B, also shown in FIG. 7C, by elements in the form of stirrups 28 screwed against the bars 24 and 25. The cylindrical posts 27 of the variant of FIG. 7A act as trunnions for the pure pivot connection between each spider and a sidewall of the chassis. On this pin is engaged a yoke 32 whose portion in cylinder portion is rigidly attached to one end of the spider. This arrangement is identical to the provision 6, 7 of FIG. 1.

As to the arrangement according to figs. 7B and 7C using stirrups 28, it can be seen that the position of these stirrups along the frames can be modified according to the desired executions. The stirrups 28 each comprise two cheeks 29 arranged one above the other and facing the inside of the frame. These cheeks serve as bearings for the pivoting of the ends of a vertical axis 73 secured to the end of the spider, playing a role similar to the axis 27 to replace the yoke 32. This vertical axis of rotation of the end of the The spider may be in the same plane formed by the longitudinal axes of the tubes 24, 25 as in the example of FIG. 7A or offset with respect to this plane as in the example of FIG. 7C.

The principle of offset of the axis of rotation of the braces can be applied both for the fixed axis of rotation of the rear cross and for the axis of rotation sliding before the spider. Thus, in FIG. 7A, the sliding axis of rotation before 63 of the spider is shown in the plane of the longitudinal axes rectilinear sliding bars 24, 25, while in the variant of FIG. 7B, the axis of rotation sliding before 63 'is offset with respect to said plane.

Figs. 7A and 7B, as well as FIG. 8A, also show a possible arrangement for sliding and pivoting connections between one end of each spider and the corresponding flank. Bars 24 and 25 of the second embodiment are rectilinear profiles which have along one of their edges a rib 33, 34 of constant profile, extending over the entire length of the bar, defining a linear longitudinal axis of sliding for the sliding connection brace on the flank. According to figs. 7A and 8A, each spider 30, 31 has at its sliding end a transverse end piece 63 integral with the spider, bearing at its two ends pivoting rollers 64, 65 provided with grooves 66, 67 fitted to the profile of the ribs 33 and 34. , the pivot axis common to the rollers 64, 65 and the end piece 63 is perpendicular to the horizontal axes of the bars 24, 25 as defined above, and the grooves 66, 67 engage on the ribs 33 and 34 It is understood that the guidance of the braces during the separation of the flanks 22 and 23 is thus ensured.

Finally, FIG. 8B shows another variant for the sliding and pivoting connection between braces such as 30, 31 and bars such as 24, 25. Between the bars 24, 25 of each side is engaged a brace support plate 68 with a lateral notch 69, and whose upper and lower edges 70, 71 have grooves similar to those of the rollers 64, 65. These grooves are obviously engaged on the ribs 33 and 34. In 1'échancrure 69 is mounted a vertical axis 72 on which pivots 31. The vertical axis 72 of rotation of the spider mounted in the lateral notch 69 may be in the same plane as that formed by the two longitudinal axes of sliding straight bars 24, 25 as shown in FIG. 8A or in a parallel plane shifted according to another possible conformation of the parts.

A heavier and more massive embodiment of the frame according to the invention is shown in FIG. 9. Here, the two sides 35 each formed of a rectangular frame are connected by two pairs of double braces 36, 38 and 37, 39 crossing each other on the same axis, at a distance from each other, the double braces 36, 38 and 37, 39 being integral at their ends, as can be seen more clearly in FIG. 13, each pair of braces being mounted on a pivot axis 40, 41. Whatever the folded, semi-folded or open position of the frame, the common axis of the two pairs of braces is always located in the middle between the flanks and parallel to their plans. The distance between the two pairs of braces may be greater or less depending on the desired performance for the chair. The two parallel flanks 35 comprise, as in the embodiments already described, auxiliary elements for mounting two steerable front wheels and two load wheels (not shown). The folding system uses here the two pairs of braces 36, 38 and 37, 39 whose pivot axes 40 and 41 are superimposed. Amounts 42, 43 and 44, 45 are rigidly fixed to the ends of the crosspieces so that the entire system forms two rigid frames intersecting on the pivot axis 40, 41. In each of these frames, one of the uprights forms the sliding connection device of the frame on the bars respectively upper and lower of a side while the other upright is a pivoting joint, using a socket or clevis on the rear pillar of the other side. This gives a layout quite similar to that of the first embodiment, shown in FIG. 1, extremely simple and robust, very easy to maneuver, even for furniture or vehicles that have to withstand heavy loads. According to a variant of this embodiment (not shown), the pairs of braces 36, 38 and 37, 39 are not integral at their ends.

Fig. 9 also shows that the two uprights 43 and 44 carry halfway up the outer elements in the form of rotating handles 46, 47. They represent the control of a locking means of the sliding links of the pairs of braces on the upper and lower bars of the flanks. In fact, the frames of the various exemplary embodiments can be equipped with locking systems as desired in the example of FIG. 9.

Other examples of locking systems will now be described with reference to FIGS. 10 and 11. Thus, the two flanks 48 and 49 of the frame of FIG. 10, whose structure is similar to that of the first embodiment with a single pair of braces, are connected to the front of the frame by an articulated structure formed of two links 50, 51, hinged at one end on the uprights front of each of the flanks 48, 49 and at the other end to one another so as to form a compass, so that in the semi-folded or fully folded position of the frame, the compass is open while in unfolded position the two rods are locked in the extension of one another. This system, which can be doubled at the rear of the chair, supports the seat 52. The backrest 53 is also shown in FIG. 10. Alternatively, the rod system shown in FIG. 10 could be replaced by a system with several rods abutting each other keystone. A lever control would then allow the user to modify himself the width of the chair. The bracing elements could have a certain thickness and be connected by a flexible band.

Another embodiment of a locking system is schematically shown in FIG. 11. A frame similar to that of fig. 1 comprises two parallel flanks 54 and 55 connected by two braces 56, 57 articulated on a central pivot 58. The sliding connections 59 and 60 allowing the mobile ends of the braces to move along the sidewalls 54 and 55 are subjected to a stress of limitation of their displacements by a system of articulated links 61, 62 whose functioning is clearly from fig. 11. When the frame is in fully open position, the links 61, 62 are tensioned and any subsequent movement of the slides is prohibited until the beginning of a folding of the frame. Although the rods 61, 62 have been shown only on the sidewall 55 of the chassis, this locking system could also be mounted on both sidewalls 54 and 55.

The realization of the frame with braces articulated around vertical axes allows to provide a foldable backrest on the front because, when the frame is folded, it does not overflow over the armrests. A chair made with this arrangement allows to offer unparalleled compactness so far for its transport. Indeed, the only incompressible, non-removable or non-folding elements of a wheelchair being the wheels, the arrangement of the chair according to the present invention, with horizontal braces, folding backrest on the front and quick release wheel of the type. known, can be easily stored and transported in a box of almost square shape with dimensions barely larger than the diameter of the wheel, as illustrated in FIG. 12.

In addition, the design of the articulated frame articulated around vertical axes allows the realization of standardized chassis usable indifferently for different widths of armchairs.

As can be seen, numerous alternative embodiments are possible on the basis of the design of the chassis object of the invention, as described above, and the skilled person may realize others without departing from the scope of the invention. The invention.

Thus, all the examples described are illustrated with adjustable wheels fixed to the front of the wheelchair, the wheels carriers being in the back. But of course, the steerable wheels can be arranged at the rear, the load wheels being at the front of the chair. Similarly, it is possible to have the load wheels in the center of the wheelchair with steerable wheels at the front and rear.

Claims

claims A foldable wheelchair frame having two rigid and non-deformable sidewalls (1, 2; 22, 23; 35; 48, 49; 54, 55), a bar structure forming at least one pair of crosspieces (8; 30, 31). 36, 37, 38, 39, 56, 57) with articulated connections between the ends of the braces and the flanks, these connections being, for each spider, at one end (9, 10, 11; 63-67; 71, 43, 44, 59, 60) with horizontal sliding on one side and at the other end (6, 7; 27, 32; 28, 29, 73, 42, 45) pivoting vertical axis fixed on the other side, characterized in that each spider (8; 30, 31; 36, 37, 38, 39; 56, 57) comprises a rigid and straight profile segment, the braces of each pair extending one above the other and being pivotally connected to one another on a vertical axis (12; 40,41; 58), and in that said sliding articulated connection of each spider with a flanks comprises a sliding device t with sliding elements (10, 11; 64, 65; 59, 60, 68) each guided along a rectilinear longitudinal axis (3, 4; 33, 34) defined on the sidewall, and a vertical axis pivoting device (9; 63; 63 ') between said sliding elements and an extreme portion of the spider. 2. Chassis according to claim 1, characterized in that the flanks are frames with two horizontal bars (3, 4; 24, 25) respectively upper and lower, and at least one upright (5, 6; 26, 27, 28 ) connecting the bars at one end. 3. Chassis according to claim 2, characterized in that in each frame a post (6, 27) is a cylindrical element acting as a pin for the pivotal connection of a cross on the frame, a cylindrical yoke (7; 32) adjusted on said journal being secured to the spider. 4. Chassis according to claim 2, characterized in that, in each frame, an upright is a stirrup-shaped insert (28) secured to or fixed in an adjustable manner between said upper and lower bars, the cheeks (29). stirrup support for a pivot connecting device of a spider. 5. Chassis according to claim 2, characterized in that said sliding articulated connection of each spider with a frame comprises a pair of sliders (10, 11) each engaged on one of the bars of the frame and having the same profile as this bar and an amount (9) integral with the spider at its end, connected to the sliders by two coaxial pivoting devices whose axis is perpendicular to the parallel axes of the bars. 6. Chassis according to claim 2, characterized in that the two bars (24, 25) of each frame have a profile with a rib (33, 34) rectilinear defining said longitudinal axis of the bar, the ribs of the two bars being turned towards each other, said sliding elements (64, 65) being provided with grooves (66, 67) engaged on the ribs and guided by them. 7. Chassis according to claim 6, characterized in that said sliding elements (64, 65) are cylindrical rollers with pivoting groove coaxially on an end member (63) integral with the spider. 8. Chassis according to claim 6, characterized in that said slidable elements are grooved portions of a spider support plate (68) engaged between the ribbed bars (24, 25) of the frame, this plate bearing other a vertical trunnion on which the end of the brace (30, 31) pivots in response to longitudinal displacement of the plate. 9. Chassis according to any one of the preceding claims, characterized in that it comprises a link locking system (61, 62) or articulated spacer (50, 51) blocking the frame in the deployed position. 10. foldable wheelchair comprising a frame according to any one of the preceding claims, characterized in that, each sidewall, are connected support elements for at least one steerable wheel (17), a wheel bearing (18), a seat (13; 52) and a backrest (53). 11. A chair according to claims 9 and 10, characterized in that the seat is a flexible structure (52) associated with at least one system of articulated rods (50, 51) constituting said locking system. 12. A chair according to claims 9 and 10, characterized in that the seat is a structure consisting of two rigid parts hinged to one another, said hinge parts constituting said locking system.