WO1994021208A1

WO1994021208A1 - Wheelchair

Info

Publication number: WO1994021208A1
Application number: PCT/EP1994/000794
Authority: WO
Inventors: Harald Reinhardt
Original assignee: Harald Reinhardt
Priority date: 1993-03-16
Filing date: 1994-03-15
Publication date: 1994-09-29
Also published as: DE59401085D1

Abstract

The invention concerns a wheelchair with a seat, two side-located drive wheels and front and rear running wheels which are free to rotate about substantially vertical axes. The drive wheels are mounted at least approximately coaxially with each other about an axis which extends across the wheelchair below the central area of the seat. Together with its respective axle bearing, each drive wheel can be individually rotated, about a substantially vertical axis, between a fixed position for straight-line travel and a pivoted position for sideways travel. A first part of the wheelchair frame, comprising the chassis and the drive wheels and rear running wheels, and a second part of the wheelchair frame, comprising the seat and back (if any) and the front running wheels, can be rotated with respect to each other about a transverse horizontal axis.

Description

wheelchair

The invention relates to a wheelchair with a seat, two side drive wheels and front and rear wheels which are freely pivotable about respective substantially vertical axes, the drive wheels of which are at least approximately coaxially mounted on an axis line which runs transversely under the seat surface, and between a position are adjustable for straight travel and a position for lateral travel.

With known wheelchairs, even with so-called active wheelchairs, which are also suitable for sports, the mobility and finiteness is very limited due to the design. This is particularly noticeable in small apartments, as well as on larger work surfaces such as tables, where the wheelchair user wants to reach for things that are out of his immediate reach. The required maneuvering with the wheelchair takes time and requires a lot of free space. Similarly, sleepers and steps, even if they are only a few centimeters high, prove to be an insurmountable obstacle in many cases.

To increase the flexibility of movement, an electrically powered wheelchair is known ("LEM", brochure from Sanitätshaus Wißmann & Co., Düren), which is on the underside a frame has five wheels distributed around the circumference, each pivotable about a vertical axis and coupled in this pivoting, and a central drive wheel, the pivoting position of which is also coupled to the running wheels and, moreover, is coupled to the seat located above the frame, which is therefore can turn on the spot and continue in any direction. The design effort for this wheelchair is very high. Also, a transverse displacement of wheelchairs is known per se (DE-A 31 33 636), namely with the aid of rollers which are extended in such a way that the drive wheels rigidly arranged for forward travel are lifted off the ground for the transverse displacement. However, the patient cannot do the operation by hand and the ability to move the auxiliary casters does not provide him with any particular maneuverability of the chair, especially since the changeover is energy-intensive and no rapid rolling movement is possible on the auxiliary rollers. A wheelchair is also known (DE-A 30 05 871), which comprises two large drive wheels on an axis which runs approximately centrally under the seat surface and further comprises a frame cross with four wheels, the cross point of which is also centered under the seat ¬ area. This wheelchair is already relatively manoeuvrable, since it can turn on the spot by turning the two drive wheels in opposite directions, but maneuvering for a change of location takes a certain amount of time and it is not possible to overcome thresholds and steps. The stability of the wheelchair against tipping forward and backward is also questionable. In another known wheelchair (FR-A 2 383 822) of the type mentioned, the construction of which basically resembles that according to DE-A 30 05 871, the axis of the drive wheels can still be rotated overall about a vertical central axis of the wheelchair. However, such a construction is not possible in the case of large-wheeled hand-operated wheelchairs and also leads to stability problems and difficulties in contact with the ground in the event of unevenness. In contrast, the invention is intended to enable rapid maneuverability and easy mobility of the wheelchair. This is achieved by two measures which are effective in particular in combination, but also to a certain extent individually, namely in that the drive wheels, including their respective axle bearings, individually about a respective essentially vertical axis between an applied position for straight travel and a transverse position for lateral travel are pivotable and that the wheelchair consists of a first frame part comprising a chassis with the drive wheels and the rear or the front wheels and a second frame part comprising the seat surface with possible backrests and the front or rear wheels, which mutually about a transverse horizontal pivot axis are pivotable.

Due to the fact that the wheels can be divided at right angles and the frame parts can be tilted, the patient sitting in a wheelchair can, for example, roll back and forth along a furniture edge without having to turn the chair and himself, even on uneven floors, but he can also If necessary, turn on the spot and finally, without losing contact of the drive wheels with the ground even briefly, overcome thresholds up to a few centimeters high.

The wheelchair can be a manual gearbox or a motorized wheelchair; the measures according to the invention prove to be advantageous in both cases. However, they are preferably used in a hand-operated wheelchair, which is particularly suitable for agile movements and quick adjustments due to its smaller dimensions and lower weight. Likewise, the invention can be used both in a rigid and in a collapsible wheelchair, but the use of the measures according to the invention in a rigid wheelchair, such as corresponds to the active and sports wheelchairs, is preferred, since these wheelchairs are due to their greater stability compared to the weight are better suited for rapid movements and the wheelchair according to the invention is particularly suitable for narrow apartments and the like, while its maneuverability, for example outdoors, is less of an issue.

The line of the axes of the drive wheels in the applied position, in which these wheels are essentially coaxial to one another, preferably runs transversely below the central region of the seat surface, that is to say in front of the user's center of gravity, and the pivot axis of the frame parts is preferably opposite one another just below the seat and slightly behind the patient's center of gravity, which improves the possibility of turning on the spot with minimal traffic space requirements and also the pivoting of the frame part, which includes the seat and preferably the front wheels, caused by the patient's upper body movement is facilitated.

The pivoting angle of the drive wheels about the respective vertical axis is preferably 90 °, the wheels in the position for straight travel (0 °) and for transverse travel (90 °) and, if necessary, also in one or more intermediate positions by simple measures, for example should be lockable with the help of a perforated sheet. The wheels can also be coupled to one another for pivoting, which is advantageous, for example, for one-armed paralyzed patients, since the two drive wheels (except when cornering) must be parallel to each other in every pivoting position for driving. However, the possibility of the transverse position means that the size of the wheels is limited if the wheels are not to be mounted very far outwards, since they partially pivot under the seat. A preferred construction here is that according to claim 5, in which the ratio of the wheel diameter to the seat width is such that the transverse wheels overlap on both sides in segments. If, on the other hand, the wheels have a common central plane in the transverse position, the The distance between their vertical pivot axes must not be less than the wheel diameter, unless the pivot angle is to be limited to an angle below 90 °. This version is therefore most suitable for mechanically, especially electrically powered, wheelchairs in which the wheel size is not a critical size. The drive wheel pivoting can also be designed to be electrically controllable.

The rear and front wheels are naturally used for support, whereby tipping over backwards is particularly avoided. The tiltable pivoting of the frames and thus the possibility of lifting the front and / or rear wheels without losing contact with the other wheels and the drive wheels enables the driver to drive over thresholds. However, the mutually tiltable frames also prove to be advantageous when driving sideways with transverse drive wheels, in particular with slightly different ground levels between the front and rear wheels. In such a constellation, in which the drive wheels are located above a type of trough or even just above a floor recess, the drive would be interrupted in the case of a rigid frame.

The pivotability of the frame parts relative to one another is, however, preferably limited in terms of angle, in order to prevent the entire frame part comprising the seat surface from tilting backwards by 90 ° due to awkward movements. With a pivotability of up to a maximum of 10 °, a threshold of 5 cm in height can be overcome in a wheelchair of normal size. The provision of driving over higher thresholds is only of limited use in hand-operated wheelchairs, since the driving force required for this is very high.

When driving sideways, a step that has to be overcome in this transverse direction is less problematic, especially since the two drive wheels successively overcome the step and, with a corresponding wheel arrangement, always the front or that represent the rear wheel, so that at most the wheels lift off between them, but this does not affect the forward and backward swinging of the seat due to the mutual pivotability of the frame parts in connection with the weight of the user sitting on the wheelchair.

The construction is particularly expedient in that the pivot axis of the frame parts lies behind one another behind the patient's center of gravity and the frame part, which contains the seat surface, carries the front wheels; in this case, the patient can easily raise the front wheels by throwing his upper body backwards and bring them over a threshold. If it is reversed, that is to say that the pivot axis lies in front of the center of gravity and the rear wheels are connected to the seat frame part, it can tilt the seat forward, for example by tilting the upper body forward, the rear wheels Raise the impellers in order to then overcome a threshold in reverse travel. Also possible, although less preferred, are constructions in which the pivot axis of the frame parts is close to the center of gravity, for example also in the wheel axis of the drive wheels in their straight-ahead position. In this case, springs must be provided between the frame parts and it is more difficult for the patient to lift the front or rear wheels.

A design in which the tilt pivot axis of the frame parts can be adjusted so that it is either further forward or further back, it is possible to adapt the wheelchair to the individual requirements of different patients. And with a construction that includes a cam or thumb that engages the seat from below to raise it, the pivoting of the frame members can be accomplished by twisting the cam, thereby allowing other force to be actuated. It should be pointed out that the features and variants mentioned can be combined with one another as desired in order to create embodiments of the wheelchair according to the invention which are particularly suitable for specific applications.

Further details, advantages and developments of the invention result from the description of preferred exemplary embodiments with reference to the drawing. Show it:

1 shows a side view of a wheelchair according to the invention; FIG. 2 shows a front view of the wheelchair according to FIG. 1; 3 shows a front view of the wheelchair according to FIG. 1 in a different working position;

4 shows a top view of the wheelchair in the first working position, with the seat partially cut out to make the parts underneath visible; Figure 5 is a plan view of the wheelchair in the second working position. 6 shows a side view of the wheelchair corresponding to FIG. 1 on a reduced scale, but partly in a separate representation of its frame parts; FIG. 7 is a partial view corresponding to the representation of FIG. 2 of a modified embodiment, on the same scale as FIG. 2; 8 shows a view corresponding to FIG. 4 of a modified embodiment; FIG. 9 views corresponding to FIG. 6 of the wheelchair according to FIG. 8, with part of the left drive wheel being cut away; FIG. 10 is a view corresponding to FIG. 1 of a further modification.

1 to 6 consists of a first frame part 1 and a second frame part 2, which are connected to one another in a hinge-like manner. 6 are the two Frame parts are shown not only in the assembled state but also in the separated state. On the first frame part 1, which represents a type of chassis, there are a left drive wheel 3, a right drive wheel 4 and a single rear wheel 5. In the embodiments that are not shown, two rear wheels can also be provided, for example. Since the wheelchair shown is one with a manual drive, a handrail ring 6 is attached to each of the drive wheels 2 and 3. The second frame part 2 comprises a seat surface 10 and a backrest 11 (possibly existing side backrests are not shown) as well as two front running wheels 12 arranged approximately on the line of the driving wheels 3 and 4. The running wheels can be pivoted in the usual way about respective vertical axes, which are designated in accordance with 13.

In the example shown, the frame part 1 consists essentially of square tube and the frame part 2 essentially consists of a round tube, which in places is covered with fabric.

The frame parts 1 and 2 are connected to one another via a pivoting or hinge axis 16, which is determined by two ball joints 17 in the example shown. A bracket 18 on both sides of the second frame part 2 is used to hold the ball joints 17, which tab protrudes from the underside of the circumference of the seat surface 10, so that the axis 16 extends just below the seat surface in the transverse direction, that is to say at 90 ° to the straight forward direction . The ball-and-socket joints 17 lie at a distance of 10 to 15 cm from the edge between the seat surface 10 and the backrest 11, that is to say still behind the perpendicular line running through the center of gravity of an average patient, which is indicated at 19 in FIG. 1 is.

In the position according to FIG. 1, a cross member 23 belonging to the second frame part 2 and running transversely under the seat surface 10 sits on a cross member 24 of the first frame partly 1. The cross members 23 and 24 are, in relation to the normal direction of travel of the wheelchair, in front of the hinge axis 16, in the example described also in front of the center of gravity line 19. When the cross members 23 and 24 lie one on top of the other, the frame parts have a pivoting angle of 0 ° relative to one another . By pressing the patient sitting on the wheelchair with his back against the backrest 11, the second frame part 2 can be pivoted clockwise about the axis 16 relative to the first frame part 1, as shown in FIG. 1, whereby the front Lift the impellers 12 off the ground. The pivoting is limited by stop elements 25 indicated in the drawing, which limit the pivoting angle to an order of magnitude of 10 °. Such pivoting is sufficient to raise the front wheels 12 about 5 cm above the ground.

In the embodiment described, the first frame 1 consists of a frame welded construction made of metal with a bracket 29 which supports the rear wheel 5 and which extends obliquely from an edge region into the region of the longitudinal center plane of the wheelchair. The rear wheel 5 lies in the plan behind the backrest 11 and thus at least a sufficient distance behind the plumb line 19, even when the frame part 2 is pivoted back. Sit on both sides on a frame-like inner frame part of the first frame part 1 - in the Fig.n 2 and 3 hidden by the spars of the second frame part - bearing 30 (Fig. 1) with a substantially vertical axis of rotation in the vertical plane of the axes of the drive wheels 3 and 4. In the bearings 30 knuckle bolts 31 are mounted, which in turn the stub axles for bearings 32 of the drive wheels 3 and 4 wear. The drive wheels 3 and 4 can thus be pivoted about the respective bearing axis of the bearing 30 in question, namely by a pivoting angle of 90 °, starting from the straight-ahead position according to FIGS. 1, 2 and 4. In FIG two bearings 30 and the two halves of the kingpin 31 for the wheel 3 above and below the Wheel bearing 32 visible.

The bearings 32 are located approximately at the distance of the wheel radius under the plane of the seating surface 10 when development in plan view of the side of the seat surface, and are Arbeitsstel¬ for straight travel approximately coaxially ^"to each other. In the plan view, they are located approximately beneath the center of the seat surface 10, that is to say in front of the line 19 running through the center of gravity of the patient. The center of gravity thus engages in a triangular plan between the bearings of the drive wheels 3 and 4 and the rear wheel 5.

The pivoting is carried out for each drive wheel by a pivot lever which is connected to the relevant kingpin 31, namely a pivot lever 33 for the left drive wheel 3 and a pivot lever 34 for the right drive wheel 4. The pivot levers are used to simplify the illustration 33 and 34 are not shown in FIGS. 2, 4 and 5. They are in the working position according to FIGS. 1 and 2, that is to say for driving straight ahead, in the area between the drive wheels 3 and 4, the pivoting lever 33 being directed towards the front and the pivoting lever 34 towards the rear.

The pivoting range of the wheels 3 and 4 is limited by stops so that each of the wheels can be pivoted by 90 ° from the initially parallel position according to FIGS. 1 and 2, namely the wheel 3 to the rear and the wheel 4 to the front, wherein they are in the end positions again have parallel center planes that have a mutual distance corresponding to twice the length of the steering knuckle between the axis of the bearing 30 and the center of the wheel bearing. This distance is not only sufficient to allow a segment-wise overlap of the two wheels, as can be seen in FIG. 3 in the area 38, but also between the wheels 3 and 4, which are thus transverse, there is still space for the load-bearing frame part of the first frame part 1 .

In the manner not detailed in the drawing, the drive wheels 3 and 4 are in their pivoting end Positions and if necessary also lockable in one or more intermediate positions. For this purpose, for example, on the one hand on the frame part 1 and on the other hand on the stub axle pin 31 or on the lever 33, 34 circular ring segments 40 with holes or resiliently or retractably protrusions engaging in the holes. The retraction z. B. can be controlled by depressing the relevant lever 33 or 34. Intermediate pivot positions between the end positions can have the advantage that a larger number of directions of travel is made available thereby and in a given intermediate position there is also the minimum of the traffic area requirement. The detents are advantageous in that the drive wheels 3 and 4 must always be exactly parallel in each straight-ahead driving position in order to produce a defined direction of travel. On the other hand, a non-parallel wheel position can be used to quickly correct the angular position of the wheelchair relative to the work surface edge or the like.

In a further embodiment, the pivoting movements of the wheels 3 and 4 can also be coupled to one another in a manner not shown, for example by a cable or chain hoist, by a connecting shaft which engages via bevel gears on bevel gears sitting on the steering knuckles, or in one appropriate reduction also via pull and push rods. In the case of such a coupling, one of the levers 33 and 34 can optionally be omitted, for example if the patient is only able to operate on one side anyway.

The drive wheels 3 and 4 have a diameter which in the example shown is slightly smaller than the height of the underside of the seat surface 10 above the floor. The pivoting of the wheels 3 and 4 is possible in such a way that their vertical diameter just comes to lie under the seat surface 10. If the wheel diameter is larger, the axes of the bearings 30 must be moved further outwards. For the hand drive there are on the one hand near handrail rings 6 and on the other hand, large diameters of the drive wheels 3 and 4 are desired. The training shown represents the optimum between these opposite demands.

If necessary, the wheelchair can be built collapsible, e.g. B in that the horizontal struts of the frame can be telescopically pushed together or folded like scissors in a manner known per se.

The following maneuvers can be carried out with the wheelchair according to FIGS. 1 to 6: straight-ahead driving on a flat route is problem-free. If the wheelchair approaches a threshold or step, the patient leans against the backrest 11, if necessary suddenly, causing the front wheels 12 to lift off the floor. With simultaneous feed by means of the drive wheels 3 and 4, the wheels 12 come over the threshold and possibly behind them back to the ground, whereupon the drive wheels 3 and 4 also take the threshold by means of vigorous drive via the handrail rings 6, without the non-positive in between To have lost contact with the ground. The front wheels 12 then rise again briefly from the ground, but come back to it when the rear wheel 5 is also pulled over the threshold.

If it is now a narrow aisle that the wheelchair user wishes to reverse, he can do so in the usual way by reversing. However, it is also possible for him to turn on the spot by rotating the drive wheel 3 and at the same time turning the drive wheel 4 backwards - or vice versa - and thus to reverse the narrow gear forward. Driving down over the threshold previously overcome in the opposite direction makes no difficulties , because the drive wheels always maintain contact with the ground.

For example, if the long corridor is between an elongated work surface and the wall, the wheelchair user can turn in front of the work surface by turning on the spot and turning 90 ° again position. This is quicker, however, if he puts the drive wheels 3 and 4 crossways and can now drive to the right or left as desired without turning the seat 10. The wheels 5 and 12 each set themselves in the new direction of travel.

In the event of incomplete parallelism of the wheelchair to the edge of the work surface at the beginning of the transverse travel, the wheelchair user can adjust his basic orientation not only by swiveling back and counter-rotating the drive wheels, but also by bringing the drive wheels into different swivel positions, in particular one in a straight-ahead position and one in the transverse position, and then by a small rotation of the straight-out drive wheel cause the wheelchair to rotate about the base point of the transverse drive wheel. If the wheel axes are not at right angles and not parallel to one another, the base point of the transverse drive wheel also performs a certain rolling movement in this adjustment.

If, during the transverse movement, a floor step runs parallel to the seat surface or the floor is not completely flat, for example in the form of a carpet edge, a channel or a grate or in the case of hollows or bumps in the floor, the second frame part takes on the first frame part a slight incline without affecting the ability of the wheelchair to move in the transverse direction. The drive wheels always stay on the ground thanks to the frame, which can be folded in at right angles to the direction of travel.

In the case of an L-shaped work surface edge, for example, intermediate pivoting angles of ± 45 ° can be helpful. In this case, however, the total swiveling of the drive wheels by 90 ° is not sufficient; at least 135 ° is required for this.

In the preferred embodiment according to FIGS. 1 to 6 drive wheels 3 and 4 sit on steering knuckles and can therefore overlap in area 38. In particular, in cases where the wheel size is less important, for example in the case of electrically powered wheelchairs, smaller wheel diameters can also be used and the wheel can be pivotable about an axis that coincides with the vertical wheel diameter or the vertical axis. A corresponding embodiment is shown schematically as a partial representation in FIG. 7. A drive wheel 43, which is seated on the first frame part 1 as in the first embodiment, can be pivoted about a pivot axis 44 which lies in the center plane of the wheel. Accordingly, it sits on a swivel bracket that is angled at the end over the wheel. A motor 46 with a reduction gear also sits on the swivel bracket 45 and can be swiveled together with the wheel 43. In a further embodiment of this embodiment, the swiveling movement can also be electrically driven, which may be necessary depending on the type of disability of the wheelchair user.

The modification according to FIGS. 8 and 9 serves the purpose of adapting the wheelchair to the personal dimensions of the patient. The force to be exerted on the backrest 11 for pivoting the frame depends on the distance between the plumb line 19 and the hinge axis 16. If line 9 is shifted forward from an average value due to the individual figure of the patient, it could result that the force required for lifting the running wheels 12 is too high for the patient. According to FIGS. 8 and 9, this distance can be adjusted. The first frame part 1 has instead of the fixed ball joints 17 a bracket-like support body 51, which - in the example shown - has five holes 52, and the second frame part 2 has two support brackets 53 which surround the support bracket 51 and each of which also has five holes 54 , which are arranged in the same way as the holes 52 and are aligned in pairs for the two brackets 53. In this respect, the arrangement could also be reversed. The row of holes 52 and the rows of holes 54 are aligned with one another and one of the holes 52 and a pair of holes 54 are connected to one another by a bolt 55, which then forms the hinge axis. In the present example, which has 1 and 2 rows of holes with five successive holes in each of the frame parts, five different positions of the hinge axis relative to the frame parts 1 and 2 and specifically relative to the backrest 11 can be selected, while their mutual position in the normal, not tilted position of the frame parts remains unchanged. Fig. 8 shows the position of the pin 55 for a heavy patient and Fig. 9 for a slim patient.

10 shows, in addition to the displaceable hinge axis, a possibility for lifting the impeller 12 not by throwing the upper body backwards, but by actuating a lever 61 which is fastened on an axis 62 which is rotatably mounted on a bracket 63 of the frame part 1 and when the frame part 2 is pivoted relative to the frame part 1 via a cam, a curve or a thumb 64 against the weight of the patient. The axis 62 runs horizontally under the seat 10. Such a device for lifting the frame part 2 is particularly useful for patients who suffer from multiple sclerosis and no longer have enough strength to pivot the frame parts of the embodiments according to FIGS. 1 to 6 against one another. If the patient's performance is even lower, the bracket 63 can also be rotated by an electrical or other drive.

All of the previously described embodiments can be combined with one another as desired based on their characteristics, which results in special variants that are particularly suitable for different purposes.

Claims

1. Wheelchair with a seat (10), two side drive wheels (3, 4) and front and rear wheels (5, 12) which can be freely pivoted about respective substantially vertical axes (13) and whose drive wheels are at least approximately coaxial on an axis ¬ never (of 32) are stored, which runs across under the seat, and between a position for straight travel (Fig. 1, 2, 4) and a position for transverse travel (Fig. 3, 5) are adjustable, characterized in that the drive wheels (3, 4) including their respective axle bearings (32) individually about a respective substantially vertical axis (of 30) between a position for straight travel (FIGS. 1, 2, 4) and a transverse position for cross travel (Fig. 3, 5) are pivotable.

2. Wheelchair according to claim 1, characterized in that the axis line (of 32) in the applied position of the drive wheels (3, 4) extends transversely below the central region of the seat surface (10).

3. Wheelchair according to claim 1, characterized in that the wheel diameter is equal to or less than the free height under the seat (10).

4. Wheelchair according to claim 1, characterized in that the axis line (of 32) in the applied position of the drive wheels (3, 4) extends transversely below the central region of the seat surface (10), and that the wheel diameter is equal to or less than the free one Height under the seat (10).

Wheelchair according to claim 3, characterized in that the drive wheels (3, 4) can be pivoted about the respective substantially vertical axis (of 30) The steering knuckles sit and are parallel to each other in the transverse position and overlap (at 38) in the view from front to back.

6. Wheelchair according to claim 3, characterized in that the pivot axis (44) of the preferably electrically (of 46) driven drive wheels (43) coincides with the vertical wheel diameter.

7. Wheelchair according to claim 4, characterized in that the drive wheels (3, 4) sit on the respective substantially vertical axis (of 30) pivotable stub axles and in the transverse position Stel parallel to each other and in the view from the front to the rear overlap (at 38).

8. Wheelchair according to claim 4, characterized in that the pivot axis (44) of the preferably electrically (of 46) driven drive wheels (43) coincides with the vertical wheel diameter.

9. Wheelchair according to one of claims 1 to 8, characterized in that the drive wheels (3, 4) are seated on wheel holders (31) which can be pivoted about parallel substantially vertical axes and which are coupled to one another with respect to the pivoting about the substantially vertical axes are.

10. Wheelchair with a seat (10), two side drive wheels (3, 4) and front and rear wheels (5, 12) which can be freely pivoted about respective substantially vertical axes (13) and whose drive wheels are at least approximately coaxial an axle line is never mounted, which extends transversely under the seat, in particular according to claim 1, characterized in that the wheelchair consists of a chassis with the drive wheels (3, 4) and the rear or front wheels (5, 12) comprising a first frame part (1) and a second frame part (2) comprising the seat surface (10) with possible backrests (11) and the front or rear wheels (12, 5), which can be pivoted relative to one another about a transverse horizontal pivot axis (16) .

11. Wheelchair according to claim 10, characterized in that the front wheels (12) sit on the second frame part (2).

12. Wheelchair according to claim 10, characterized in that it has five wheels (3, 4, 5, 12), of which the first frame part (1) in addition to the two drive wheels (3, 4), the only rear wheel (5th ) carries and the second frame part (2) carries two front wheels (12).

13. A wheelchair according to claim 10, characterized in that the pivot axis (16) about which the frame parts (1, 2) can be pivoted relative to one another, just below the seat surface (10) and just behind the center of gravity of one seated on the seat surface Vertical transverse plane (19) containing patients.

14. Wheelchair according to claim 10, characterized in that it has five wheels (3, 4, 5, 12), of which the first frame part (1) in addition to the two drive wheels (3, 4), the only rear wheel (5th ) carries and the second frame part (2) carries two front wheels (12), and that the pivot axis (16) of the frame parts (1, 2) against each other just below the seat surface (10) and just behind the center of gravity of one seated on the seat surface Vertical transverse plane containing patient (19).

15. Wheelchair according to claim 10, characterized in that the pivotability of the frame parts (1, 2) against each other is limited by stops (25) to a maximum swivel angle of 8 ° to 12 °.

16. Wheelchair according to claim 14, characterized in that the pivotability of the frame parts (1, 2) against each other by stops (25) is limited to a maximum pivoting angle of 8 ° to 12 °.

17. Wheelchair according to one of claims 10 to 16, characterized in that one of one of the frame parts (1,

2) supported rotatable axle (62) is connected to a lever (61) rotatable by the patient and to a cam device (64) which is on the underside of the seat (10) on the one hand or on the other frame part (2, 1 ) on the other hand attacks at a point in front of the transverse horizontal pivot axis (16).

18. Wheelchair according to one of claims 10 to 16, characterized in that the transverse horizontal

The pivot axis (55) can be selected between different positions which are at different distances from the plane of the backrest (11).

19. Wheelchair according to claim 18, characterized in that the first frame part (1) and the second frame part (2) each have a series of holes (52, 54), the holes of the frame parts being aligned in pairs, and that by one A bolt (55) passes through the mutually aligned pairs of holes and can be detached for assembly in another pair of holes.