EP1878415B1 - Auxiliary drive device for manual wheelchairs - Google Patents

Abstract

The device has a driving motor (5), two drive wheels (1,2), a steering device and fastening parts for docking at a wheelchair. The two drive wheels are positioned commuting around a floating axle (180) and are interconnected by a differential. The floating axle runs perpendicularly to the axis of rotation of the two drive wheels in a plane. The drive wheels are rigidly connected with the driving motor.

Description

The invention relates to an auxiliary drive device for manual wheelchairs, which is also called wheelchair scooter in the trade.

Such a wheelchair scooter serves to be detachably connected to a wheelchair, in particular a manually driven wheelchair, in order to drive this wheelchair. A well-known, in the trade under the name "RollAid" marketed wheelchair scooter is in Fig. 18 shown. A standard wheelchair with two front pivoting wheels in 2003, also called castors, and two large rear wheels in 2004, to which the wheelchair scooter can be connected, is shown in a partially sectional view in FIG Fig. 19 shown. According to the wheelchair Fig. 19 is left in the direction of travel left rear wheel for the purpose of better illustration of fasteners omitted.

The well-known wheelchair scooter 1000 according to Fig. 18 has a drive wheel 1001, which is drivable by means of a drive motor 1002. The motor 1002 is designed as an electric motor, which is supplied with power during operation by a rechargeable battery (rechargeable battery) 1003. The drive wheel 1001 can be pivoted together with the drive motor 1002 via a steering column 1004 and a handlebar 1005 with respect to the wheelchair scooter housing to perform steering movements.

The known wheelchair scooter 1000 has first holding means 1006 and second holding means 1007 and centering bevels 1008, which are in pairs and on both sides the wheelchair scooter are arranged. Furthermore, the wheelchair scooter 1000 has at its opposite end of the drive wheel 1001 two small rollers 1009, of which Fig. 13 only a roller is shown.

In its decoupled from a wheelchair state, the wheelchair scooter 1000 on the drive wheel 1001 and the two rollers 1009 are moved.

For coupling the wheelchair scooter 1000 to a known wheelchair 2000, as in Fig. 19 2, the wheelchair 2000 is driven from behind over the wheelchair scooter 1000, whereby the end of the wheelchair scooter opposite the steering column 1004 passes between the foot rests 2001 of the wheelchair 2000. During assembly, the wheelchair scooter 1000 is centered over the centering ramps 1008 in cooperation with crossbars 2002 of the wheelchair 2000 opposite the wheelchair 2000. At the same time, the second holding means 1007 of the wheelchair scooter 1000 engage in corresponding holding elements of the wheelchair 2000.

A pivotable holding mechanism, which is fixed to the wheelchair 2000, in cooperation with run-up slopes 1007A of the second holding means 1007, causes the rear end of the wheelchair scooter 1000 to be raised with the casters 1009 in the ready-coupled state of the wheelchair scooter 1000 on the wheelchair 2000 opposite the floor surface is. The wheelchair scooter 1000 is thus held in the ready-docked state at its rear end to a holding element of the wheelchair 2000 (not shown) and rests with its drive wheel 1001 on the running surface.

The centering bevels 1008 are such that the front end of the wheelchair when performing the docking process is raised so far that the two front pivotable wheels 2003 are lifted off the ground in fully docked condition.

In the known wheelchair scooter 1000 only one wheel, namely the drive wheel 1001 is used as the drive and steering wheel. This drive wheel 1001 is connected via a rigid axle with the steering mechanism and the drive components, the engine 1002 and a transmission. Wheel and drive are on top of each other in an escape. As a result, only a very small wheel diameter can be used.

The driving force is transmitted in the known wheelchair scooter 1000 via a chain drive from the transmission to the drive wheel 1001. Although the drive unit builds relatively narrow due to the superimposed arrangement, it is very high despite the small wheel diameter of the drive wheel 1001. The large height of the drive including the drive wheel reduces the possibility of mounting. The cultivation of the known wheelchair scooter 1000 is thus possible only with wheelchairs with a large seat height. The small diameter of the drive wheel 1001 also severely limits the ability to overcome obstacles. In addition, such a small drive wheel requires high speeds with correspondingly small torques.

A generic auxiliary drive device with two drive wheels is from the DE 43 25 092 A1 and the DE 19 935 506 A1 known.

The invention has for its object to provide a wheelchair scooter, which is improved in its properties in view of the technical problems set out above.

This object is achieved by an auxiliary drive device for manual wheelchairs (wheelchair scooter) having the features of patent claim 1. Advantageous embodiments of the invention are specified in the subclaims.

The auxiliary drive device according to the invention, which is designed to be connected to a wheelchair and to pull the wheelchair in this docked state, has a drive motor, a steering device and fastener for docking to a wheelchair. Unlike the wheelchair scooter described above, which has only one drive wheel, the auxiliary drive device according to the invention has two drive wheels. By providing two drive wheels a symmetrical construction of the drive is possible. This symmetrical design reduces the overall height of the drive. The wheels may extend laterally beyond the drive motor or other components, so that despite a low overall height, a large wheel diameter is possible. Due to the large wheel diameter higher obstacles can be overcome. The low height, which is made possible by the provision of two drive wheels through the possible compact design, which optimally utilizes the existing installation space in the wheelchair behind the footrests holding legrests, also allows for attachment to wheelchairs with relatively low seat height.

The two drive wheels are mounted oscillating about a pendulum axis. The pendulum bearing of the drive wheels improves traction on slightly level ground and when turning. It allows the same torques to be transmitted to the road. The provision of a differential allows smooth steering, d. H. a steering that can be operated with little effort. In addition, the differential causes the two drive wheels, for example, when cornering, to move at different speeds to each other and possibly even rotate in opposite directions to each other.

The two drive wheels are preferably driven by a worm gear and the pendulum axis runs preferably in a plane perpendicular to the axis of rotation of the two drive wheels.

The drive motor is preferably rigidly connected to the drive wheels. This means that the drive motor oscillates around the pendulum axis together with the drive wheels. The entire drive unit comprising drive motor, drive wheels and a drive train provided between the drive motor and the drive wheels, which can be designed optionally with or without a reduction or transmission gear, is preferably suspended resiliently. Corresponding spring elements on the one hand cause suspension and damping of shocks perpendicular to the axis of rotation of the drive wheels and on the other hand, either cumulatively or alternatively, ensure that the drive wheels from a deflected position return to a central position, for example, when the drive wheels are raised.

As a spring element, one or more leaf springs, coil springs or elastomeric elements may be provided.

The drive motor is preferably an electric motor designed as a brush motor. In addition, the auxiliary drive device according to the invention preferably has an electromagnetic brake.

• Fig. 1 eine bevorzugte Ausführungsform eines erfindungsgemäßen Zusatzantriebs für manuelle Rollstühle (Rollstuhlscooter) in einem Zustand zeigt, in dem das System ausgeschaltet ist und
• Fig. 2 den Rollstuhlscooter gemäß Fig. 1 in einem Zustand zeigt, in dem das System eingeschaltet ist.
• Fig. 3 zeigt den Rollstuhlscooter gemäß Fig. 1 in der Betriebsstellung gemäß Fig. 2 sowie einen handelsüblichen Rollstuhl, wobei bei dem Rollstuhl klappbare Fußauflagen zum Zwecke der besseren Darstellung weggelassen wurden;
• Fig. 4 zeigt den Rollstuhlscooter und den Rollstuhl gemäß Fig. 3 in einer Zwischenstellung des Andockvorganges, wobei zum Zwecke der besseren Darstellung das linke hintere Laufrad des Rollstuhls weggelassen sind;
• Fig. 5 zeigt einen vergrößerten Ausschnitt von Fig. 4;
• Fig. 6 zeigt die Darstellung gemäß Fig.4 aus einer anderen Perspektive,
• Fig. 7 zeigt einen vergrößerten Ausschnitt aus Fig. 6;
• Fig. 8 zeigt den Rollstuhlscooter und den Rollstuhl gemäß den Figuren 3 bis 7 in vollständig angedocktem Zustand, wobei zum Zwecke der besseren Darstellung das linke hintere Laufrad des Rollstuhls weggelassen ist;
• Fig. 9 zeigt einen vergrößerten Ausschnitt aus Fig. 8;
• Fig. 10 zeigt eine teilweise im Schnitt gehaltene Detailansicht der Hubeinrichtung des Rollstuhlscooters gemäß den Fig. 1 und 2 in der Stellung gemäß Fig. 1;
• Fig. 11 entspricht Fig. 10, wobei die Stellung der Hubeinrichtung der Stellung des Rollstuhlscooters gemäß Fig. 2 entspricht;
• Fig. 12 ist eine weitere Detailansicht des Rollstuhlscooters gemäß den Fig. 1 und 2;
• Fig. 13 zeigt als Detailansicht des Rollstuhlscooters gemäß Fig. 1 die Antriebseinheit mit den beiden Antriebsrädern und dem Antriebsmotor in einer perspektivischen Darstellung von vorne;
• Fig. 14 zeigt in einer leicht perspektivischen Darstellung von hinten unter Weglassung weiterer Komponenten des Rollstuhlscooters gemäß Fig. 1 die Antriebsräder in einer durch eine Bodenunebenheit hervorgerufenen Schrägstellung;
• Fig. 15 entspricht Fig. 14, wobei sich die Antriebsräder in der neutralen Mittellage befinden.
• Fig. 16 zeigt in einer schematischen Darstellung das schräg verzahnte Zahnrad des Schneckengetriebes sowie das zwischen den beiden Antriebsrädern angeordnete Differential in einer Draufsicht;
• Fig. 17 ist eine perspektivische Darstellung von Fig. 16;
• Fig. 18 ist eine perspektivische Darstellung eines Rollstuhlscooters gemäß dem Stand der Technik und
• Fig. 19 ist eine Detailansicht eines handelsüblichen Rollstuhls.

A preferred embodiment of the invention will be described below with reference to the accompanying drawings, wherein

• Fig. 1 shows a preferred embodiment of an auxiliary drive according to the invention for manual wheelchairs (wheelchair scooter) in a state in which the system is turned off and
• Fig. 2 according to the wheelchair scooter Fig. 1 in a state in which the system is turned on.
• Fig. 3 shows the wheelchair scooter according to Fig. 1 in the operating position according to Fig. 2 and a commercial wheelchair, wherein the wheelchair hinged footrests have been omitted for the purpose of better illustration;
• Fig. 4 shows the wheelchair scooter and the wheelchair according to Fig. 3 in an intermediate position of the docking operation, wherein for the purpose of better illustration, the left rear wheel of the wheelchair are omitted;
• Fig. 5 shows an enlarged section of Fig. 4 ;
• Fig. 6 shows the illustration according to Figure 4 from a different perspective,
• Fig. 7 shows an enlarged section Fig. 6 ;
• Fig. 8 shows the wheelchair scooter and the wheelchair according to the FIGS. 3 to 7 in fully docked condition, with the left rear wheel of the wheelchair omitted for better illustration;
• Fig. 9 shows an enlarged section Fig. 8 ;
• Fig. 10 shows a partially sectioned detail view of the lifting device of the wheelchair scooter according to the Fig. 1 and 2 in the position according to Fig. 1 ;
• Fig. 11 corresponds to Fig. 10 , wherein the position of the lifting device of the position of the wheelchair scooter according to Fig. 2 corresponds;
• Fig. 12 is another detail view of the wheelchair scooter according to the Fig. 1 and 2 ;
• Fig. 13 shows as a detailed view of the wheelchair scooter according to Fig. 1 the drive unit with the two drive wheels and the drive motor in a perspective view from the front;
• Fig. 14 shows in a slightly perspective view from behind, omitting other components of the wheelchair scooter according to Fig. 1 the drive wheels in an inclined position caused by a floor unevenness;
• Fig. 15 corresponds to Fig. 14 , wherein the drive wheels are in the neutral center position.
• Fig. 16 shows a schematic representation of the helical gear of the worm gear and arranged between the two drive wheels differential in a plan view;
• Fig. 17 is a perspective view of Fig. 16 ;
• Fig. 18 is a perspective view of a wheelchair scooter according to the prior art and
• Fig. 19 is a detailed view of a standard wheelchair.

Fig. 1 shows a preferred embodiment of an auxiliary drive device according to the invention for manual wheelchairs (wheelchair scooter) in a state in which the system is turned off, and Fig. 2 shows the wheelchair scooter according to Fig. 1 in a state in which the system is turned on.

The wheelchair scooter is movable on two drive wheels 1, 2 and two rollers 3, 4. The drive wheels 1, 2 can be driven by a drive motor 5 and directed by a steering column 6 and a handlebar 7. The steering rod 7 is fastened to a pivotable operating unit 100. The drive motor 5 is designed as an electric motor and is powered by a rechargeable battery (accumulator) 8 with power. The operating unit 100 has two operating levers 101, 102 designed as a rocker, which actuates, for example, with the index finger and / or the thumb of an operator to cause a forward and / or reverse movement can be. On the control unit also provided a push button for issuing a Hubsignals, a light switch, which can also be designed as a push button, two push-button for uncoupling the wheelchair scooter from a wheelchair (will be explained in detail below), a rotary potentiometer, by turning a default setting of the driving speed allows and can be switched on and off by pressing, a display with an LED (light emitting diode) indicator to indicate the state of charge of the battery 8 and an immobilizer to secure the vehicle against unauthorized use.

As in Fig. 1 is shown, the battery 8 receiving part of the wheelchair scooter, which also contains the elements for attachment of the wheelchair scooter to a wheelchair and is hereinafter referred to as mounting part 200, opposite to that part of the wheelchair scooter, which contains the drive wheels 1, 2 and the drive motor 5 and hereinafter referred to as drive part 300, lowered. In this switched-off state, which is also referred to below as idle state, the wheelchair scooter can be pushed by unlocking a brake provided on the drive by an operator, for example, for storage at his storage place or for mounting to a wheelchair to a point from which the wheelchair can be connected to the wheelchair scooter.

The steering column 6, together with the handlebar 7 and the operating unit 100 completely and without tools from the remaining part of the wheelchair scooter removable. To remove it only requires a simple Entriegelns and withdrawing the entire unit upwards. The use of tools or a previous release of electrical connectors is not required. By removing the steering unit, it is easier to get in and out of the wheelchair when the wheelchair scooter is docked to a wheelchair. To the Assembling the steering unit, the steering column 6 is simply inserted into a corresponding recess and snaps automatically. Additional locking is provided only to eliminate play.

In addition, the rechargeable battery (accumulator) 8 can be easily removed and replaced with a handle from its corresponding holder. A charge socket provided on the housing of the battery 8 also allows charging of the accumulator outside of the wheelchair scooter. For example, a fully charged battery 8 can always be kept ready while another battery 8 is in use. In addition, it is possible to charge the rechargeable battery 8 in the installed state in the wheelchair scooter via a charging socket, which is attached to the control unit 100.

The easy dismantling of the wheelchair scooter by removing the steering column 6 and removing the rechargeable battery 8 also allows easy transport of the wheelchair scooter.

Fig. 2 shows the wheelchair scooter according to Fig. 1 in operating condition, but without docked wheelchair. It can be seen that in this operating state, the fastening part 200 is raised relative to the drive part 300. If one chooses for this position shift with respect to the position according to Fig. 1 the fastening part 200 as a reference system, is in Fig. 2 the drive part 300 is lowered relative to the attachment part 200. The meaning of this operating position is explained below in connection with the docking of the wheelchair scooter on a wheelchair and with the driving operation of the composite between wheelchair scooter and wheelchair.

First, the operation of docking the wheelchair scooter to the wheelchair will be explained below. This is especially on the FIGS. 3 to 9 Referenced. Fig. 3 shows the wheelchair scooter in the operating state according to Fig. 2 The wheelchair 600 has two large wheels 601, which can be provided with gripping rings (not shown) over which the person sitting in the wheelchair can drive the wheelchair by hand, as well as two freely rotatable small wheels 602, which are articulated via appropriate handlebars with a large trailer and castors called. The wheelchair also has handles 603, over which the wheelchair, possibly with a person sitting in the wheelchair, can be pushed by an assistant. Furthermore, the wheelchair has one or more cross braces 610. Such cross braces are a common technical solution by means of which foldable wheelchairs are effectively stiffened in running order condition. The wheelchair 600 also has hinged footrests 604 (see, for example, in US Pat Fig. 4 ), which are attached to swing-away or removable legrests and for the purpose of better appearance in Fig. 3 not shown.

To dock the wheelchair to the wheelchair scooter, the wheelchair is placed in the wheelchair Fig. 3 shown moved to the ready wheelchair scooter. For this purpose, the folding footrests are folded up or the legrests completely pivoted to the side and the wheelchair is driven over the mounting part 200 until the steering column 6 of the wheelchair scooter approaches the front edge of the seat cushion of the wheelchair 600. This condition is in different perspective representations in the Fig. 4 and 6 shown. The Fig. 5 and 7 show enlarged cutouts to illustrate the docking and fastening elements in more detail, wherein Fig. 5 Fig. 4 corresponds and Fig. 7 Fig. 6 ,

It goes without saying in this context that for the sake of better clarity, not every representation has its own Reference number is inserted. The presence, arrangement and operation of the respective components will be readily apparent to those skilled in the art by comparison of the various figures with each other in the context of the present specification.

The wheelchair scooter has pairwise front fasteners 210, of which due to the perspective view, for example, in the Figures 2 and 3 only one is shown. Each of the two front fastening elements 210 has a centering bevel 211 and a hook 212, resulting in a J-shaped cross section. The centering bevel 211 serves to center the wheelchair scooter in cooperation with the cross struts 610 of the wheelchair 600 with respect to the wheelchair 600 when assembling the wheelchair and the wheelchair scooter. The centering bevels 211 are inclined both with respect to an imaginary plane that runs vertically through the central axis running in the direction of travel of the wheelchair, for example the folding plane of a foldable wheelchair, and with respect to the running surface on which the wheelchair is moving. While the inclination relative to the imaginary vertical center plane of the wheelchair, which substantially corresponds to the inclination of the cross struts, causes the centering of the wheelchair scooter with respect to the wheelchair 600, the inclination relative to the running surface has the consequence that in the course of assembly the small wheels ( Castors) 602 be lifted off the running surface or from the ground. In the last part of the docking movement, the hooks 212 surround the cross struts 610 of the wheelchair 600.

It will be appreciated that the front fasteners 210 may be provided in different sizes and replaceable to allow the wheelchair scooter to be assembled with different wheelchairs 600 that may have cross struts of varying thickness.

At the end opposite to the drive part 300, the wheelchair scooter has rear fastening elements 220, which are likewise designed in pairs. The rear fastening elements 220 each have an insertion ramp 221 and a hook element 222.

On the wheelchair 600, a stroke locking device 700 is attached. This stroke locking device 700 allows docking of the wheelchair scooter on any standard wheelchair. It is designed specifically for the wheelchair scooter and designed with respect to their mounting options on the wheelchair 600 so, for example, by variable fasteners with holes at different distances and the like that it can be attached to a variety of different wheelchairs.

The stroke locking device has a pivotable lifting element 710 with a lifting rod 711. The lifting element 710 is designed so that during the docking process in the course of bringing together wheelchair 600 and wheelchair scooter, the lifting rod 711 engages with the insertion ramp 221. This causes a pivoting of the lifting element 710 about a pivot axis which passes through the bearing points 712, 713 of the lifting element 710. The lifting element 710 is in this case from a substantially horizontal position, as in the FIGS. 4 to 7 is brought into an approximately vertical position, as in the FIGS. 8 and 9 is shown. During this pivoting movement in the view according to the FIGS. 4 to 9 runs in Urzeigesinn, the fastening part 200 of the wheelchair scooter is raised, so that the rollers 3, 4 lose contact with the running surface or pad. This condition is in the FIGS. 8 and 9 shown.

At the same time, in this disfigurement of the lifting element 710, a lever arranged on the lifting locking device 700 surrounds Locking hook 720 (see Fig. 5 ) the locking bar 711 and thereby causes the lifting element 710 is held in this end position.

To release the locking hook 720, a lifting magnet 230 is provided on the fastening part 200, above the rollers 3, 4 and arranged between them. Upon actuation of the lifting magnet 230, the locking hook 720 is pivoted so that it releases the lifting rod 711 and the lifting element 710 designed as a swivel bracket is released from its operating position in accordance with FIGS FIGS. 8 and 9 , ie from the approximately vertical position, back to the approximately horizontal position according to the FIGS. 4 to 7 pivoted. As a result, the rear part of the fastening part 200 is lowered and released, the rollers 3, 4 again put on the running surface or support.

The operation of the solenoid 230 via the aforementioned two push-button switch (not shown) for uncoupling the wheelchair scooter from the wheelchair, which are provided in the operating unit. For reasons of safety, it is necessary here that both push-button switches are actuated simultaneously in order to trigger the actuation of the lifting magnet 230. This safety feature prevents unintentional actuation of a push-button switch from causing unwanted decoupling of the wheelchair scooter from the wheelchair.

The following is now the driving of the wheelchair with docked wheelchair scooter explained. As described above, when the wheelchair is docked, the castors 602 of the wheelchair 600 are raised. As further described above, in the further course of the docking operation, the rollers 3, 4 are raised at the rear end of the attachment part 200 of the wheelchair scooter. In the fully docked state of the composite of wheelchair scooter and wheelchair 600 this composite is thus on the two large wheels 601 of the wheelchair and on the handlebar 7 and steering column 6 steerable parallel drive wheels 1, 2 of the wheelchair scooter. This ensures that the drive wheels 1, 2 permanently have optimum traction, since there are no load components on the small drive wheels (castors) 602. In addition, the space that the small drive wheels (Castoren) 602 need when cornering, can be neglected, as they can freely commute.

The person sitting in the wheelchair can now preselect a speed via the corresponding switch on the operating unit 100 and initiate a forward or reverse drive with the actuating levers 101, 102. The steering takes place via the handlebar 7. Steering direction and steering movement thus arise intuitively.

As already mentioned above, the drive part 300 can be changed relative to the fastening part 200 in its position. This is not only possible in the undocked state of the wheelchair scooter, as in the Fig. 1 and 2 shown, but also in the docked state. Also in this state, the driving part 300 can be raised. This has the consequence that the small drive wheels (Castoren) 602 lower and get back into contact with the running surface or the ground. The drive part 300 can also be raised so far that the drive wheels 1, 2 are completely raised from the ground. In this position, although the wheelchair scooter is docked, the wheelchair can easily be driven and controlled manually via the large wheels 601. Unlike the prior art described in the introduction, the rolling resistance of the electric drive does not have to be overcome here. The wheelchair user must therefore in the event that he wants to move the wheelchair manually on the large wheels 601 or pushing handles, not the wheelchair scooter again, but can only the drive wheels 1, 2 of the wheelchair scooter and thereby completely lift off the ground and thus achieved the same maneuverability and ease of maneuverability of the manual wheelchair 600 without wheelchair scooter, although it is still connected to the wheelchair 600. If the wheelchair user so wishes, he can also remove the steering column 6. This allows, for example, a closer approach to a table.

If the electric drive is desired or needed again, it is available almost immediately by simply switching on the system. The drive wheels are then lowered again and the small drive wheels (castors) 602 lifted off the ground. A renewed coupling of the wheelchair scooter is, unlike the prior art, not required.

A preferred embodiment of the raising and lowering of the drive wheels 1, 2 causing lifting device will be described below with reference to the FIGS. 10 to 12 explained.

As already stated, in the described embodiment, the drive wheels 1, 2 are lowered or raised together with the drive part 300. Fig. 10 shows in a partially sectioned view, in which the steering column 6 are shown only as a fragment and essential parts of the fastening part 200 are omitted for the purpose of better illustration, the Fig. 1 corresponding position in which the drive part 300 and thus the drive wheels 1, 2 are raised in the docked to a wheelchair state of the wheelchair scooter or in which the mounting part 200 of the wheelchair scooter is lowered in the undocked state. This position corresponds to the idle state, ie the state in which the wheelchair scooter is switched off. It is also the maximum raised position of the drive wheels 1, 2.

Fig. 11 corresponds to Fig. 10 , however, shows differently Fig. 10 the operating state, ie the state in which the small wheels (castors) 602 of the wheelchair 600 are lifted from the ground or the running surface in the docked state or, in other words, in which the fastening part 200 is lifted in the undocked state, as in FIG Fig. 2 shown so that the docking process can take place. This position corresponds to the operating state, ie the state in which the wheelchair scooter pulls the docked wheelchair. It is also the maximum lowered position of the drive wheels 1, 2.

The drive part 300 including the drive wheels 1, 2 of the drive motor 5 and the steering column 6 and the components connected thereto are movably mounted relative to the attachment part 200 via a linear column guide 320, which extends substantially vertically. The substantially vertical lifting movement for lowering and raising the drive wheels from the ground via a geared motor 321, which is designed as an electric motor. The rotational movement generated by the gear motor 321 is converted into a linear movement via an additional gear with a push rod 322 and a push rod gear 323. At maximum raised drive wheels 1, 2 or lowered attachment part 200, ie the in the FIGS. 1 and 10 shown position, the push rod 322 is at top dead center of the additional transmission. The two bearing axes of the push rod 322 and the axis of rotation of the push rod gear 323 are in this case in a common plane. This means that no moments due to external load on the geared motor 321 act.

As in Fig. 11 shown, the push rod is at fully or maximum lowered drive wheels, ie the in Fig. 2 shown position, in the bottom dead center of the additional gear. Also in this position No moments due to external load acting on the geared motor 321.

The positions according to Fig. 10 and Fig. 11 , ie the maximum raised or maximum lowered position of the drive wheels is detected via mechanical end position buttons 324, 325. These give on reaching the respective end position corresponding signals to a control device (not shown), which serves to control the lifting device.

The following is the drive unit of the wheelchair scooter according to Fig. 1 with the two drive wheels 1, 2, the drive motor 5, an electromechanical brake 15, a worm gear 60 and a differential 70 and the suspension of the drive unit explained in more detail.

The drive wheels 1, 2 are arranged with the interposition of the differential 70 parallel to each other. The differential 70 is shown schematically in FIGS Fig. 16 and Fig. 17 and has two large bevel gears 71A, 71B and two bevel gears 72A, 72B. The small bevel gears 72A, 72B are mounted in a large helical gear 61 of the worm gear 60. The large bevel gears 71A, 71B of the differential 70 are rotatably connected to the drive shafts 73A, 73B of the drive wheels 1, 2 connected.

The helical gear 61 of the worm gear is driven by a worm wheel (not shown) connected to the drive motor 5. The drive motor 5 is an electric motor designed as a brush motor. Also connected to the drive is an electromechanical brake 15.

The entire drive unit is mounted pendulum about a pendulum axis 180. Like from the Fig. 14 and Fig. 15 can be seen, the pendulum axis 180 extends in a plane which is perpendicular to the axis of rotation of the drive wheels 1, 2. Like from the Fig. 14 and Fig. 15 also visible, pivoted when bumps occur the entire drive unit with the electromagnetic brake 15, the drive motor 5 and the drive wheels 1, 2 about the rotation axis 180th

In the Fig. 14 and Fig. 15 is also schematically indicated a spring element 190, which acts to the effect, the drive wheels 1, 2 from a deflected position according to Fig. 14 back to the middle position according to Fig. 15 bring to. This spring element 190 or a further spring element (not shown) can also be provided for possible noises in strong or frequent oscillations of the two suspended from a rigid axle construction, ie in their relative position to a fixed drive wheels 1, 2 or when driving on cobblestones to dampen or prevent.

Reference numerals:

• Wheelchair scooter 1000
• Drive wheel 1001
• Engine 1002
• Battery (accumulator) 1003
• Steering column 1004
• Handlebar 1005
• Holding means 1006
• Holding means 1007
• Run-up slopes 1007A
• Centering bevels 1008
• Casters 1009
• Operating unit 1010

• Wheelchair 2000
• Foot pads 2001
• front wheels 2003
• rear wheels 2004

• Drive wheels 1, 2
• Casters 3, 4
• Drive motor 5
• Steering column 6
• Handlebar 7
• Battery (accumulator) 8
• electromechanical brake 15

• Worm gear 60
• helical gear 61

• Differential 70
• large bevel gears 71A, 71B
• small bevel gears 72A, 72B
• Drive shafts 73A, 73B

• Operating unit 100
• Operating lever 101, 102

• Swing axle 180

• Spring element 190
• Fastening part 200
• front fastening elements 210 centering bevel 211
• Hook 212
• rear fasteners 220 insertion ramp 221
• Hook element 222

• Lifting magnet 230

• Drive part 300
• Linear column guide 320
• Geared motor 321
• Push rod 322
• Push rod gear 323
• End position button 324, 325

• Wheelchair 600.
• big wheels 601
• Handles 603
• Cross struts 610
• small wheels (castors) 602
• foldable footrests 604

• Lift locking device 700
• Lifting element 710
• Lifting rod 711
• Storage points 712, 713

• Locking hook 720

Claims (13)

1. Auxiliary drive device designed to be connected to a wheel chair (600) and to pull the wheel chair in a state where it is docked thereto, this auxiliary drive device comprising the following features:

   - a drive motor (5),

   - two drive wheels (1, 2),

   - steering means (6, 7), and

   - fixing elements (210, 220) for docking to a wheel chair,

   characterized in that the two drive wheels (1, 2) are arranged to oscillate about an oscillating axle (180) and connected to each other by means of a differential (70).
2. Auxiliary drive device according to claim 1, characterized in that the oscillating axle (180) extends in a plane perpendicular to the axis of rotation of the two drive wheels (1, 2).
3. Auxiliary drive device according to claim 1 or 2, characterized in that the two drive wheels (1, 2) are rigidly connected to the drive motor (5).
4. Auxiliary drive device according to one of the preceding claims, characterized by a spring element (190) acting on the drive wheels (1, 2).
5. Auxiliary drive device according to claim 4, characterized in that the spring element (190) is arranged such that it can move the two drive wheels (1, 2) from a deflected position to the central position.
6. Auxiliary drive device according to claim 4 or 5, characterized in that the spring element (190) is arranged such that a suspension in a direction perpendicular to the axis of rotation of the two drive wheels (1, 2) is permitted.
7. Auxiliary drive device according to one of claims 4 to 6, characterized in that the spring element (190) is a leaf spring.
8. Auxiliary drive device according to one of claims 4 to 6, characterized in that the spring element (190) is a flat spiral spring.
9. Auxiliary drive device according to one of claims 4 to 6, characterized in that the spring element (190) is an elastomer element.
10. Auxiliary drive device according to one of the preceding claims, characterized in that the two drive wheels (1, 2) are driven by means of a worm gear pair (60).
11. Auxiliary drive device according to one of the preceding claims, characterized in that the drive motor (5) is an electric motor.
12. Auxiliary drive device according to claim 11, characterized in that the drive motor (5) is a brush motor.
13. Auxiliary drive device according to one of the preceding claims, characterized by an electromechanical brake (15).

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