EP0430794B1 - Collapsible wheelchair and bag for transporting such a chair when collapsed - Google Patents

Abstract

PCT No. PCT/FR90/00856 Sec. 371 Date Nov. 5, 1991 Sec. 102(e) Date Nov. 5, 1991 PCT Filed Nov. 27, 1990 PCT Pub. No. WO91/07935 PCT Pub. Date Jun. 13, 1991.A wheelchair including two large carrying wheels mounted on opposite sides of a central frame is provided. One portion of the central frame is collapsible and is designated to support a seat. Another portion of the central frame defines a footrest. Steering wheels associated with the footrest also are provided. Each carrying wheel includes an outer ring and an inner ring. The outer and inner rings are concentrically oriented relative to each other such that the outer periphery of the inner ring and the inner periphery of the outer ring engage bearing elements located therebetween. The outer periphery of the outer ring is adapted to support a tire. The volume defined by the inner ring is devoid of any axle, shaft, or spoke. The frame is attached to the inner ring of the adjacent carrying wheels by releasable connectors.

Description

The present invention relates to a wheelchair, of the type comprising two large carrying wheels mounted on either side of a central frame, part of which supports a seat and another part constitutes a footrest provided with steered wheels.

Wheelchairs of this type most often have a folding structure so that they can be stored in tight spaces, and in particular in the boot of a motor vehicle.

Due to their folding mode, generally in the manner of a pantograph, the wheelchairs currently known, however, retain, once folded, a significant bulk which, added to the fact that certain parts remain protruding, makes them particularly difficult to transport to the main (see in particular documents DE-A-3819925 and US-A-4593929).

The present invention proposes to remedy this drawback and, to do this, it relates to a wheelchair of the type specified in the introduction, which is characterized in that each of its carrying wheels is formed of a rim which, carrying the pneumatic, directly constitutes the outer ring of a peripheral bearing whose inner ring, of large diameter, devoid of any hub, shaft or radius, carries the frame fixed to it by releasable fixing means.

There is thus a wheelchair from which one can dismantle all the elements among which the carrying wheels, completely hollowed out internally, can by being superimposed, delimit a housing capable of receiving all or part of the other constituent elements of the wheelchair, thus reducing in a appreciable measure of the size of the disassembled chair. To make this space a minimum a certain number of additional provisions are also provided.

Thus, according to an additional characteristic of the invention, the seat of the wheelchair and the part of the frame which supports it form a separate assembly from the footrest, which has a folding structure designed and dimensioned such that once separated from the wheels and folded, said assembly forms a packet whose volume is entirely contained in that delimited by the two superimposed carrying wheels.

In addition, the footrest independent of the rest of the frame, has the shape of a closed arch projecting from the front of the load wheels and held at its rear between them by releasable means of attachment to their inner ring. respective, this hoop advantageously having, in all directions, external dimensions at most equal to those of the space delimited by the two superimposed supporting wheels as well as an internal length and width preferably greater than the corresponding dimensions of the package constituted by the seat and its support disassembled and folded.

In addition, each of the steering wheels of the chair is preferably supported by a pivoting stand mounted on a respective lateral branch of the roll bar by an articulation with an axis perpendicular to the pivot axis of the stand, and comprising a retractable member d immobilization in the deployed position.

Thanks to these provisions, it is indeed possible, after complete disassembly of the chair, to store all of the constituent elements of the central part of the latter inside the two large superimposed load wheels to thus constitute a package whose external dimensions are limited to those of the latter and which can therefore be easily transported as flat hand luggage and space-saving.

To facilitate disassembly of the wheelchair, it is further provided according to another characteristic of the invention that the means for fixing, to the inner rings of the carrying wheels, the footrest arch are formed at each end of the rear branch of this one, by a bolt provided with a notch, which slides in an internal elastic ratchet keeper, integral with the inner ring of the corresponding load wheel, and that on each side of the seat support part of the frame , the means for fixing the latter to the respective inner ring comprise two groups, mutually distant along the periphery of the latter, of two elements assembly snap into each other, one of these elements being integral with the inner side of the inner ring and the other on the opposite side of said seat support portion of the frame.

The reassembly of the chair will also be facilitated if, in each of said groups, one of the assembly elements is a protruding finger ending in a ball joint and the other is a receiving part provided with a housing for inserting this finger and an elastic pawl, the receiving part of at least one of the groups having the shape of a clamp in which the corresponding projecting finger engages laterally.

To guarantee perfect rigidity of the assembled chair, it will also be preferable for the protruding finger to have, over at least part of its length, a polygonal cross section and for the housing provided in the receiving part to have a cross section complementary to that of the finger.

Finally, the position of at least one of the assembly elements of each group is adjustable along the inner side of the corresponding inner ring and or respectively on the opposite side of the seat support part of the frame to allow a easy adjustment of the seat height or its lateral or rear tilt.

The removable wheelchair according to the invention can also be made self-propelled without losing the aforementioned advantages, namely essentially the possibilities of rapid assembly and disassembly and the storage of its various constituent elements in a minimum volume, facilitating its transport.

To this end, each of the two carrying wheels of the chair is advantageously provided with a motor carried by one of its rings and causing the second ring to rotate by means of a transmission mechanism cooperating with the latter, the motor , and possibly its source, the energy supply, being retained inside the central recess of the wheel considered without encroaching on a space having, in the plane of said wheel, dimensions smaller than the transverse dimensions and longitudinal of the arch.

According to a preferred embodiment of this self-propelled chair, the motor, and optionally its power supply source, is carried by the inner annular surface of the ring inner of the wheel considered, and the outer ring has a flange of which an annular part, folded in front of the inner ring, cooperates with said motor transmission mechanism.

Preferably, said transmission mechanism is constituted by a pinion or a set of pinions, meshing with a crown with internal toothing carried by said annular part folded back from the outer ring. It may alternatively consist of a friction roller or a set of friction rollers cooperating with a coating with a high coefficient of friction of said annular part.

According to another characteristic, in a direction parallel to the axis of the wheel, the motor, with its transmission mechanism and possibly its energy supply source, has a dimension less than twice the thickness of the wheel and does not go not beyond a lateral plane of congestion of the latter.

Finally, the two assembly elements of at least one of the groups are advantageously provided respectively with electrically conductive interior parts, in mutual contact, each isolated from the external body forming the mass of the assembly element considered, this to, when reassembling the chair, be able to play the role of automatic electrical connectors which can be used to, in the case of the use of an electric motor, close the electric control circuit of the latter.

• la figure 1 est une vue en perspective de ce fauteuil roulant ;
• la figure 2 le représente, vu de côté, sous forme schématique ;
• la figure 3 est une vue en coupe partielle dans le plan III-III de la figure 2 ;
• la figure 4 est une vue agrandie de la base repliable du siège du fauteuil ;
• les figures 5 à 7 sont des vues en perspective agrandies des dispositifs de fixation des différents éléments d'armature aux bagues intérieures des roulements des routes porteuses ;
• les figures 8 et 9 illustrent le mode de montage des béquilles de support des roues directrices, la figure 9 étant une vue en coupe effectuée dans le plan IX-IX de la figure 8 ;
• les figures 10 et 11 représentent le fauteuil complètement démonté et rangé dans une housse de transport à main ;
• la figure 12 est une vue latérale schématique, à grande échelle, d'un fauteuil roulant perfectionné selon l'invention ;
• la figure 13 est une vue en perspective éclatée et agrandie d'un dispositif de fixation, analogue à celui de la figure 5, dont est muni le fauteuil roulant de la figure 12 ;
• la figure 14 est une vue en coupe agrandie faite dans le plan XIV-XIV de la figure 12 ; et
• la figure 15 est une vue en coupe, faite dans le même plan, des deux grandes roues, agencées l'une dans l'autre après démontage, du fauteuil roulant de la figure 12.

A preferred embodiment of the wheelchair according to the invention will now be described in more detail, but only by way of nonlimiting example, with reference to the accompanying drawings in which:

• Figure 1 is a perspective view of this wheelchair;
• Figure 2 shows it, seen from the side, in schematic form;
• Figure 3 is a partial sectional view in the plane III-III of Figure 2;
• Figure 4 is an enlarged view of the foldable base of the chair seat;
• Figures 5 to 7 are enlarged perspective views of devices for fixing the various reinforcing elements to the inner rings of the bearings of the bearing roads;
• Figures 8 and 9 illustrate the mounting method of the support legs of the steering wheels, Figure 9 being a sectional view taken in the plane IX-IX of Figure 8;
• Figures 10 and 11 show the chair completely disassembled and stored in a carrying case by hand;
• Figure 12 is a schematic side view, on a large scale, of an improved wheelchair according to the invention;
• Figure 13 is an exploded and enlarged perspective view of a fixing device, similar to that of Figure 5, which is provided with the wheelchair of Figure 12;
• Figure 14 is an enlarged sectional view taken in the plane XIV-XIV of Figure 12; and
• FIG. 15 is a sectional view, made in the same plane, of the two large wheels, arranged one inside the other after dismantling, of the wheelchair of FIG. 12.

In a manner known per se, the wheelchair exemplified in FIG. 1 comprises two carrying wheels 1,2 of large diameter, a seat 3 and a footrest 4 provided, in front of the carrying wheels, with two lateral guide rollers 5.

According to the primary characteristic of the invention, illustrated jointly by FIGS. 2 and 3, each of the carrying wheels 1 or 2 is formed, in the manner of a bearing, of two rings of large diameter 7.8 kept closely in contact, concentrically around one another, by means of rollers 9 interposed between them peripherally and whose axes are perpendicular to the plane of the wheel. The annular inner rings 7 of the two carrying wheels 1, 2 thus constitute entirely hollow fixed elements retaining between them the seat support 3 and the independent footrest 4, while the outer ring 8 of each wheel 1 or 2 constitutes the actual rim with a tire 10 disposed around its periphery and a handrail 11 projecting from its outer side.

The support for the seat 3 is essentially formed of two L-shaped lateral elements 12,13, the vertical branches 12a and 13a of which support the backrest 14 in seat fabric and the horizontal branches 12b and 13b the separate seat 15 also in canvas. In each lateral element 12 or 13 of the support, a double folding arm 16 or 17, forming an armrest, is articulated on one side to the vertical branch and, on the other, to the horizontal branch, which are further joined by a hinge 18, self-locking in the deployed position at right angles to the two branches. It should also be noted, with reference to FIG. 4, that the two horizontal branches 12b and 13b, the support elements 12, 13 are connected by a spider formed by two rods 19, 20 articulated one on the other in their center 21 and respectively at the rear ends of the branches 12b, 13b, as indicated in 22 and 23. By their front end, the two rods 19, 20 each slide in a grooved piece 24 or 25 welded on the inside of the horizontal branch respective. The same foldable spider structure is present between the two vertical branches 12a, 13a of the support elements 12, 13 of the seat 3.

According to another characteristic of the invention, each support element 12, 13 is assembled to the inner edge of the hollowed-out inner ring 7 of a respective load wheel 1 or 2, by two point fastening devices, positioned first on its horizontal branch 12b or 13b and the second on its vertical branch 12a or 13a.

FIG. 5 shows the first of these identical fixing devices for the two support elements. It consists, on the one hand, of a finger 26 projecting from the inside of the ring 7, perpendicular to its plane and tangentially inside it, and ending in a spherical ball joint 27, and, on the other hand, a part 28, of generally parallelepiped shape, which fits on the horizontal branch 12b or 13b, of rectangular section, of the support element 12 or 13 by a claw 29 of complementary shape, fitted internally with a pawl elastic 30 for blocking the workpiece 28. On the face, opposite the claw 29, of the workpiece 28, there opens an internal housing 31 of the latter into which the ball joint finger is inserted axially. A pivoting pawl 32 on an axis 33 and loaded by a spring not shown or by the own elasticity of the material, protrudes slightly inside the housing 31 so, after insertion of the finger 26, block it by entering a groove 34 formed between that -ci and its ball 27.

The second fixing device visible in FIG. 6 has the same overall structure as the first, except that the parallelepiped part 35 here has the shape of a clamp defined by a fixed part 36 carrying the claw 37 and a movable jaw 38 articulated around a longitudinal axis 39 and urged by a spring or by the own elasticity of the material. This clamp is open towards the rear at 55 and the ball joint finger 40 engages there laterally so as to be blocked by the jaw inside the part 35.

Returning to FIG. 1, it can still be seen that the footrest 4, without connection to the seat 3, is constituted by a closed arch which carries, at each end of its rear branch 4a, a bolt 41 substantially perpendicular to this last, shown in Figure 7, This bolt 41 which has a notch 42, is inserted in a keeper 43 secured to the inner ring 7 of the corresponding carrier wheel, in a position slightly recessed inwardly according to its radius by relative to the internal periphery of the latter, the keeper 43 being further provided with an elastic pawl 44 which engages in the notch 42 of the bolt to block it.

It should be noted here that the largest external dimensions in length and in width of the footrest arch 4 are at most equal to the internal diameter of each of the hollowed out inner rings 7 and that the space which it delimits is of a length greater than that of each of the branches 12a, 12b, 13a, 13b of the seat support elements 3. The inner annular surface of the hollowed-out inner rings 7 furthermore has a slight conicity open towards the interior of the chair, as shown in 7a in FIG. 3, and, in the exemplified embodiment, the outside length of the hoop 4 is equal to the inside mean diameter of each ring 7.

On each of the lateral branches 4b, 4c of the arch 4, is in in addition to an articulated stand 45 inclined towards the rear, which supports a respective steering wheel 5. As shown in FIGS. 8 and 9, each stand 45 consists of a short upper part 46 articulated on the inside of the arch 4 around an axis A parallel to that of the caster 5, and a longer tab 47 pivoting under the part 46 around a second axis B perpendicular to the first A. A movable lug 48 loaded by a spring 49, s 'engages in a bore 50 of the lateral branch 4b of the hoop to block the stand, relative to its axis A, in its functional position shown in solid lines in FIG. 8.

All the constituent elements of the wheelchair which has just been described, namely the two carrying wheels 1,2, the seat 3 and the roll bar 4, can be easily separated from each other by a slight traction exerted on the level of their snap fastening devices, shown in Figures 5 to 7. Once disassembled, the chair can be put in the form of a package of minimum size as follows:

Firstly, after having retracted their lug 48 by hand, the stands 45 are pivoted successively upwards and laterally around their axes A and B with the rollers 5 to fold the latter flat on the hoop 4 and inside its outline, as shown in dashed lines in FIG. 8. The support for the seat 3 is then completely folded around the joints 21 of its braces 19, 20, as shown in dashed lines in FIG. 4, and those 18 of its lateral support elements 12,13, and the fabric quarters 14,15 are rolled around the support of the seat thus folded to form a packet 51. After having placed a wheel horizontally, resting on its handrail , then installs inside its recess the hoop 4 with its rollers 5 folded. This is thus located in the inner ring 7 of the wheel by friction on its surface 7a which has a sufficient taper to retain it. Then inside the hoop and on the folded rollers 5, the package 51 is placed, as shown in Figure 10 in which the upper carrier wheel has been removed for clarity of the drawing, it being specified that when putting in place of the latter, the two adjoining wheels 1 and 2 immobilize each other thanks to the fingers 26 and 40 which pitch with gentle friction each of the conical surfaces 7a of their inner rings 7.

The package thus formed, and made rigid by the connections provided by friction between the two wheels, can then be capped around the supporting wheels 1,2 by a circular toric cover 52 with a U-section, provided with handles 53, such as that shown. in Figure 11. The package can thus be easily transported in the form of space-saving hand luggage. The O-ring cover 52 can of course be replaced by a circular cover which is entirely closed in the center.

It is specified here that the carrying wheels 1 and 2 can advantageously, according to FIG. 3, receive an external flange 56 situated inside the handrail and occupying its entire surface, being fixed therein in a removable manner or not, such that the volume thus obtained between the two flanges 56 of the two superposed wheels 1 and 2 delimits a receptacle capable of containing all the elements described above. The two wheels 1,2 with their flange 56 thus form a rigid and completely closed transport envelope, which can itself be equipped with the cover 52.

The assembly of the wheelchair will be just as easy as its disassembly, by snap-fastening.

We will start by assembling the two carrying wheels 1,2 to the side elements 12,13 of the seat support 3 previously deployed. To do this, the protruding fingers 26 of their inner ring 7 will firstly be snapped axially into the respective complementary pieces 28 of the horizontal branches of the lateral elements 12, 13, then using the axis formed by the two fingers 26, will tilt the entire seat backwards so that it engages automatically, by the jaws 35 of the vertical branches of its lateral support elements, on the corresponding fingers 40 of the inner rings 7. The last operation will consist to be latched from the front onto the inner rings 7 of the wheels 1,2, the arch on which the rollers 5 will have been previously replaced in their functional position.

Although its carrying wheels 1,2 are completely devoid of central core (spokes, hub and axis), the wheelchair according to the invention has, once reassembled, a perfect rigidity which is conferred on it by the central frame, namely the seat support 3 and the footrest arch 4, assembled between the inner rings 7, at three mutually distant points along each of them.

Returning to FIG. 2, we will also appreciate the possibility of simple adjustment of the height position of the seat 3 relative to the footrest 4, as well as of its inclination towards the rear, obtained by means of the claws 29 and 37 of the parts. 28 and 35, which allow the position of the latter to be easily modified along the respective branches of the support elements 12, 13 of the seat 3. In addition, the corresponding fingers 26 and 40 must also be movable along of each rim 7 or increased in number. In Figure 2, the seat 3 is shown simply lowered and tilted back, in broken lines, but it is also possible, thanks to the possibility of adjustment offered, to tilt it to the left or right to compensate for particular morphological characteristics of the patient and thus improve his comfort.

The removable wheelchair according to the invention can also be made self-propelled thanks to a certain number of simple arrangements which do not eliminate any of its aforementioned advantages.

FIG. 12 illustrates a preferred embodiment of such a self-propelled wheelchair, the large carrying wheels 1, 2 of which are first of all each equipped with a small direct current electric motor 57, of known type. As can be seen better in FIG. 14 for the wheel 1, this motor 57 is fixed, by its outer carcass 58, on the inner annular surface 59 of the inner ring 7 of this wheel. The motor 57, the attachment of which to the inner ring 7, will preferably be reinforced by side props, not shown, is positioned in such a way that its shaft 60 is parallel to the axis of the wheel 1 and is directed towards the outside. of the latter.

Figure 14 also shows that the outer ring 8 of the wheel 1 is provided, over its entire circumference, with a radial flange 61 which folds in front of the inner ring 7, with a slight spacing from it. The folded, annular and continuous branch 62, of this rim 61 carries, on its outer surface, a crown with internal toothing 63, centered on the axis of the wheel 1, with which meshes a pinion 64 mounted free in rotation on the face front of the carcass 58 of the motor 57, this pinion 64 meshing itself with a second pinion 65 wedged on the shaft 60 of the motor.

Miniature storage batteries 66, of a type available on the market, are fixed on either side of the engine 57, on its carcass 58, to ensure the electrical supply thereof through a four-position switch , housed in the arm 16 of the seat 3 of the chair, closest to the wheel 1 considered, where it can be actuated by means of a control handle 67 (see FIG. 14).

The electrical connection, made according to a conventional diagram between the batteries 66, the motor 57 and the joystick switch 67, is made using conductive wires which, between the wheel 1 and the seat 3, are connected via ball and socket fingers 26 or 40 and associated receiving parts 28, 35 for fixing the seat 3 to the wheel 1. For this purpose, each finger, as shown in FIG. 13 for that 26 of the first fixing device , has a core 68, conductive of electricity, which carries at its end the ball joint 27 and is enveloped by an insulating sleeve 69, inside the body 70, forming a mass, of the finger 26. Similarly, the pawl 32 is electrically isolated at 71 from the external mass of the part 28.

Thus, the electrical connection between a battery 66 and the motor 57, through the joystick switch 67, is established automatically, when the seat 3 is assembled to the wheels 1 and 2 of the chair, and does not impose any additional operation. during the almost instant disassembly of the chair.

It will also be noted in FIG. 13, that the finger 26 of the first fixing device has a polygonal section, here rectangular, and the housing 31, in which it is inserted, has an exactly complementary section, thus a perfect rigidity is guaranteed. the assembly carried out between the support of the seat 3 and the wheel 1, which by these provisions, resists in effect the mutual torsional forces between the two elements 26 and 28 snapped into each other. The end part 26a of the finger 26 is also slightly tapered to facilitate centering of the latter during its introduction into the housing 31 of the part 28.

It will be noted here that any suitable means other than the set of pinions 64, 65 can be used to make the kinematic connection between the shaft 60 of the motor 57 and the ring gear 63 of the outer ring 8 of the wheel 1, by virtue of at which the latter is rotated around the fixed inner ring 7, in one direction or the other, and at a selectable speed, from the control lever 67. This is how this set of pinions can be replaced by a friction roller or a set of such rollers in contact with the inner annular surface 62, in this case smooth and provided with a coating with a high coefficient of friction, of the outer ring 8 of the wheel 1.

Of course the second load wheel 2 is arranged in the same way as the first, with an engine-battery assembly, electrical connections and a control, as described above.

It goes without saying, moreover, that on one and the other wheels 1,2, it is possible, in place of the electric motor exemplified 57, to use a motor of another type, and in particular a small heat engine associated with fuel tanks which would then take the place of the batteries 66.

It will also be observed, with reference to FIG. 14, that on each wheel 1 or 2, the shaft 60 of the motor 57 does not go beyond the external lateral plane P of the wheel, and that, on the other side , the motor body protrudes beyond the inner ring 7 of the latter, but over a distance less than the thickness of a wheel. Furthermore, the carcass 58 of the motor 57 is very slightly detached from the surface 7a of the inner ring 7 of the wheel, on which it is welded.

Figure 15 shows that, thanks to these provisions, the two wheels 1 and 2 of the self-propelled wheelchair of Figure 12 can be superimposed on each other, without leaving any parts protruding, in the same way as those of the wheelchair described above.

In addition, in each of the wheels 1 and 2, the motor 57 and its batteries 66 are confined inside a housing delimited by the inner ring 7 of the wheel 1 or 2 considered and a cord of this ring, symbolized by the dashed line 72 in FIG. 12. This cord 72, which can moreover be embodied by a narrow plate further stiffening the fixing of the motor, is in a position such that after the two disassembled wheels 1,2 are superimposed, as in FIG. 15, the motors 57, with their batteries 66, do not encroach on the space 73 reserved, inside the two wheels, for the installation of the arch 4 at the center of which is then placed the package 51 formed by the seat 3 folded and wound on itself, as shown in Figure 10 for the first non-self-propelled wheelchair. Consequently, just like the latter, the self-propelled wheelchair of FIG. 12, despite its additional arrangements, can, after disassembly, be put in the form of a package of minimum volume easily transportable in a bag in the form of a cover. toric such as that of figure 11.

Claims (19)

1. A wheelchair of the type comprising two large carrying wheels (1,2) mounted on either side of a central frame having a collapsible portion (12, 13) supporting a seat (3) and a further portion (4) forming a footrest provided with steering wheels (5), each carrying wheel being in the form of a large diameter rolling bearing with an inner ring (7) supporting the frame and an outer ring (8) defining the rim of said wheel, the inner ring (7) of each of said carrying wheels (1, 2) being completely hollow and the frame (4, 12, 13) being on each side secured directly to said inner ring (7) of a respective carrying wheel at several points of the inner side thereof by releasable fixing means, characterized in that, after disassembly of the carrying wheels, the different frame portions have, after being collapsed, dimensions that are smaller than the dimensions of a housing delimited by the two carrying wheels placed in superposed relation with their inner sides being juxtaposed.
2. A wheelchair according to claim 1, characterized in that the footrest is independent of the remaining portion of the frame and has the shape of a closed hoop (4) projecting forwardly of the carrying wheels (1, 2) and being maintained at the rear, between the inner rings thereof by a portion (41, 43) of said releasable fixing means.
3. A wheelchair according to claim 2, characterized in that the hoop (4) comprises, at least in a lengthwise direction, an outside dimension equal to the average inside diameter of the inner rings (7), with an inner annular surface (7a) thereof having a slightly cone-shaped configuration opening towards the inside of the wheelchair.
4. A wheelchair according to claim 2 or 3, characterized in that said fixing means of the hoop comprises at each end of a rear wing (40) thereof a lock bolt (41) provided with a slot (42), said lock bolt (41) slidingly engaging a stricking plate (43) having an inner elastic catch (44) formed integrally with the inner ring (7) of the respective carrying wheel.
5. A wheelchair according to any of claims 2 to 4, characterized in that each of the steering wheels (5) is supported by a pivoting prop (45) mounted on a respective lateral wing (4b, 4c) of the hoop via an articulation having an axis (A) perpendicular to the pivotal axis (B) of the prop, and comprising a retractable member (48) for immobilising said prop in extended position.
6. A wheelchair according to any of claims 2 to 5, characterized in that at least one (1) of said carrying wheels comprises a motor (57) carried by one (7) of its rings and rotating the other ring (8) through a drive mechanism (64, 65), which cooperates with the latter, said motor (57), possibly with its power supply source (66), being retained inside the central hollow part of said at least one carrying wheel without encroaching upon a space (73) having, in the plane of said wheel, dimensions that are less than the transverse and longitudinal dimensions of the hoop (4).
7. A wheelchair according to claim 6, characterized in that said motor (57), possibly with its power supply source (66), is carried by the inner annular surface (7a) of the inner ring (7) of said at least one carrying wheel (1), and the outer ring (8) defines a rim (61) including an annular portion (62) that is bent back in front of the inner ring (7) and cooperates with said motor drive mechanism (64, 65).
8. A wheelchair according to claim 7, characterized in that said drive mechanism comprises a pinion or a set of pinions (64, 65) engagingly coupled to a gear ring having inner teeth (63), said gear ring being carried by said bent back annular portion (62) of the outer ring (8).
9. A wheelchair according to claim 7, characterized in that said drive mechanism comprises a friction roller or a set of friction rollers applying on a high friction coefficient coating of said bent back annular portion (62) of the outer ring (8).
10. A wheelchair according to any of claims 6 to 9, characterized in that, in a direction parallel to the axis of wheel (1), the motor (57) with its drive mechanism (64, 65), and possibly its power supply source, has a dimension of less than twice the thickness of said wheel (1) and does not extend beyond a lateral outer plane (P) of the latter.
11. A wheelchair according to any of claims 2 to 10, characterized in that the seat (3) and the frame portion (12, 13) supporting said seat form a collapsible structure, separate from the footrest hoop (4) which is so designed and dimensioned that, after being separated from the wheels and collapsed, it forms a packet having longitudinal and transverse dimensions that are smaller than those of the space delimited by the inside of said hoop.
12. A wheelchair according to claim 11, characterized in that on each side of the seat supporting portion (12, 13) of the frame, the fixing means for securing said frame to the respective inner ring (7) comprises two groups spaced from each other along the periphery of the latter, comprising two assembly elements snap fastenable into one another, one of said elements (26 or 40) being formed integrally with an inner side of the inner ring (7), and the other one of said elements being formed integrally with the confronting side (12 or 13) of said seat supporting portion.
13. A wheelchair according to claim 12, characterized in that, in each of said groups, one of said assembly elements is a projecting finger (26 or 40) ending in a ball joint (27) and the other of said assembly elements is a receiving part (28 or 35) provided with a housing (31) for inserting said finger and with an elastic catch (32, 38), said receiving part of at least one of said groups being in the form of a clamp (35, 38) into which the corresponding projecting finger (40) engages laterally.
14. A wheelchair according to claim 13, characterized in that said projecting finger (26 or 40) presents, along at least a part of its length, a polygonal cross-section and said housing (31) provided in the receiving part (28 or 35) has a cross-section substantially matching said polygonal cross-section of the finger.
15. A wheelchair according to claim 13 or 14, wherein the inner annular surface (7a) of the inner rings (7) of said carrying wheels has a slightly cone-shaped configuration opening towards the inside of the wheelchair, characterized in that the projecting fingers (26, 40) extend perpendicularly to the plane of the corresponding carrying wheel (1 or 2) and tangentially to said annular surface of its inner ring (7).
16. A wheelchair according to any of claims 12 to 15, characterized in that the position of at least one of the assembly elements of each group is adjustable along the inner side of the corresponding inner ring (7) and/or respectively along the side confronting the seat support portion (12, 13) of said frame.
17. A wheelchair according to any of claims 12 to 16, characterized in that said two assembly elements (26, 28 or 40, 35) of at least one of said groups are respectively provided with electrically conductive inner parts in contact with each other which are each insulated (at 69 and 71) in relation to external body (70, 28), forming ground, of the corresponding assembly element.
18. A wheelchair according to any of claims 1 to 17, characterized in that the outer ring (8) of each said carrying wheel is closed centrally by an outer flange (56).
19. A bag for transporting a wheelchair according to any of claims 1 to 18, after disassembly of the frame portions and placing of said frame portions inside the two superposed carrying wheels (1, 2), characterized in that it is generally in the form of a toroidal, circular cover having a U-shaped section and fitted with handles (53).

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