Abstract:
The invention relates to a wheelchair, including an assembly of a chair unit for a user and a support base supporting the chair unit, wherein the support base includes a number of carrying wheels for carrying the assembly, a drive element connected to the assembly for driving at least one carrying wheel and, an operating element connected to the assembly for operating the drive element. The invention also relates to an operating element for use in such a wheelchair.

Description:
BACKGROUND OF THE INVENTION  
   1) Field of the Invention 
   The invention relates to a wheelchair, comprising: an assembly of a chair unit for a user and a support base supporting the chair unit, wherein the support base is provided with a number of carrying wheels for carrying the assembly, drive means connected to the assembly for driving at least one carrying wheel, and operating means connected to the assembly for operating the drive means. The invention also relates to operating means for use in such a wheelchair. 
   2) Description of the Prior Art 
   Diverse types of wheelchairs are known from the prior art. wheelchairs driven by muscle power are for instance available commercially. In addition, the type of wheelchair stated in the preamble, the so-called motorized wheelchair, is also commercially known, wherein the drive power is produced by a different type of energy source, in particular an (electro)mechanical motor. In the known motorized wheelchairs the operating means are formed by a joystick which is arranged in a position for the user, usually on a plate connected to the support base. Such a joystick is adapted for operation with only a single hand. In addition to the advantage that the motorized wheelchair can be operated in relatively simple manner, the motorized wheelchair also has multiple drawbacks. A first drawback of the known motorized wheelchair is that the wheelchair is relatively difficult to operate by persons who are relatively weak physically, since a relatively unnatural posture must generally be assumed during operation of the joystick. Particularly in the case that long distances have to be covered in the motorized wheelchair, considerable fatigue and/or physical problems (such as for instance back or arm problems) can occur in the user. The arms of the user are furthermore not equally loaded—since the joystick can only be operated by a single hand—which can result (in the long term) in physical problems. It is noted in addition that mounting of the joystick (on the plate) is generally relatively expensive and relatively complex. There is thus for each type of motorized wheelchair an individual set of fixing means for mounting the joystick on the support base, which is relatively time-consuming. 
   The invention has for its object, while retaining advantage of the prior art, to provide an improved motorized wheelchair with which the above stated drawbacks can be prevented. 
   SUMMARY OF THE INVENTION  
   The invention provides for this purpose a wheelchair of the type stated in the preamble, characterized in that the operating means are positioned at least partially laterally relative to the chair unit. A positioning of the operating means to the side of the chair unit is relatively favourable, since the user can assume a natural posture while controlling or operating the wheelchair, which can prevent or at least counter (considerable) fatigue and/or (more serious) physical problems. Since the wheelchair according to the invention is fully motorized, no significant muscular power need be exerted by the user to transport him/herself in the wheelchair. The wheelchair according to the invention is therefore also relatively simple and light to operate. An additional advantage of the wheelchair according to the invention is that the aesthetic appearance very closely resembles the appearance of the known, manually driven wheelchair, wherein the posture of the user in the wheelchair moreover remains substantially unchanged in both types. Such similarities in appearance and posture generally have a positive influence on the user of a motorized wheelchair. Particularly when the user of a manually operated wheelchair switches to a motorized wheelchair according to the invention, a possible psychological barrier to such a transition will be lowered. Lowering of the psychological barrier will generally result in a quicker acceptance of the user of the transition from a manually driven wheelchair to a (fully) motorized wheelchair. In addition to the psychological aspect, there is usually also a cognitive aspect which plays a part for the user. The operating means of the wheelchair according to the invention are positioned such that a user can learn how to operate the wheelchair relatively quickly and independently. Such a cognitive aspect generally also contributes to the more rapid acceptance of the wheelchair by the user. It is noted that the chair unit must be broadly interpreted. Support of the user in a prone position can thus also be realized by the chair unit. The chair unit is not therefore limited to a unit in which the user can only assume a sitting position. 
   The operating means preferably comprise at least one operating member for the user, wherein the operating member is positioned at least partially laterally relative to the chair unit. In particular, the operating member serves as handgrip for the user adjacently of the chair unit and can be designed in very diverse ways. It is thus possible for instance to envisage embodying the operating member as a handle or as a conventional push rim placed adjacently of a carrying wheel. It is however noted here that the push rim does not co-rotate with the carrying wheels during motorized transport of the wheelchair, but that the push rim is connected more or less rigidly to the assembly. It is also possible to envisage integrating the operating member into an armrest of the wheelchair, whereby the natural posture of the user can be further stabilized. In a particular preferred embodiment, the operating means comprise two operating members positioned on either side of the chair unit. It is thus possible to perform the control of the drive means with two hands. An advantage hereof is that both arms of the user are substantially equally loaded, which can prevent or at least counter physical problems for instance resulting from overloading of an arm. An additional advantage of such a dual operation is that the wheelchair can be controlled with relatively high accuracy. In a further particular preferred embodiment, the operating member is adapted to undergo one or more changes in orientation. Such a change in orientation can be very diverse and may for instance include slight pivoting or rotating of (a part of) the operating means, whereby the drive means can be activated. In a particular preferred embodiment, the operating member is adapted to undergo a first change in orientation for regulating the displacement speed of the wheelchair, and a second change in orientation for manoeuvring of the wheelchair. Manoeuvring is here particularly understood to mean rotation of the wheelchair, which can be realized by providing the drive wheels with a differing speed. The or each operating member is preferably displaceable between at least two extreme positions. The two extreme positions can for instance correspond with displacing of the wheelchair forward and backward at maximum speed, wherein the operating member thus functions as a type of accelerator handle. In another preferred embodiment the operating member takes an at least substantially tubular form and is axially rotatable through a determined angle of rotation. It is possible here to envisage the operating means comprising at least one sensor connected to the assembly for sensing the change in orientation of the operating member. The signal sensed by the sensor can be further transmitted to a control unit for operating the drive means. 
   In another preferred embodiment the operating means are adapted for wireless communication with the drive means. For this purpose the operating means can comprise one or more remote controls for (de)activating the drive means. Communication can take place via infrared or radio frequencies. It is possible to economize on a number of mechanical components by applying wireless communication in the wheelchair according to the invention, which generally results in a mechanically relatively simple, motorized wheelchair with a relatively low mass. 
   In yet another preferred embodiment, the drive means are adapted for independent driving of a plurality of carrying wheels, wherein the operating members are each adapted to control a determined driven carrying wheel. Each carrying wheel or each set of mutually coupled carrying wheels can thus be operated by a single operating member. An opposite carrying wheel or set of carrying wheels can herein be operated by an opposite operating member. 
   The operating means are preferably connected to a wheel shaft received in a hub of at least one carrying wheel. The operating means can thus be coupled to the assembly in efficient manner without the operating means co-rotating with the carrying wheels during forward travel of the wheelchair. The operating means can herein be directly coupled to a motor unit forming part of the drive means. The motor unit is in that case also coupled to at least one carrying wheel. In a particular preferred embodiment, the motor unit is at least substantially arranged in a hub of a carrying wheel for driving, and can for instance be formed by a direct drive motor. In a direct drive motor the hub is driven directly by the (electric) motor without the interposing of other mechanical components. 
   In a preferred embodiment at least a part of the operating means is positioned on a side of at least one carrying wheel remote from the chair unit. The operating means are positioned on an external side of the wheelchair and can thus be reached relatively easily by the user. It is here also possible to envisage the operating means enclosing the assembly on two sides. 
   In another preferred embodiment the operating means can be locked in at least one position. It is thus possible to fix the speed of the wheelchair during standstill or transport. Such a locking thus prevents fatigue of the user, particularly during displacement over relatively long distances. It is also possible to envisage locking the operating means during standstill, whereby unintended operation of the wheelchair by the user can be prevented. It is also possible to envisage coupling the operating means to unlocking means, whereby the operating means can only be used to operate the wheelchair after unlocking. Undesired operation of the wheelchair can thus also be prevented. The unlocking means can herein be integrated into a part of the operating means, in particular the operating member. 
   In a final preferred embodiment, the operating means are releasably connected to the assembly. It is thus possible in relatively simple manner to adjust the operating means to the user and/or replace them during for instance maintenance or repair work on the operating means and/or the assembly. The operating means are here then provided with coupling means adapted for co-action with counter-coupling means forming part of the assembly, in particular of the wheel shaft. 
   The invention also relates to operating means for use in such a wheelchair. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS  
     The invention will be further elucidated on the basis of non-limitative exemplary embodiments shown in the following figures. Herein: 
       FIG. 1  shows a front view of a first preferred embodiment of a wheelchair according to the invention, 
       FIG. 2  shows a front view of a second preferred embodiment of a wheelchair according to the invention, 
       FIG. 3  shows a detail view of a part of a third preferred embodiment of a wheelchair according to the invention, and 
       FIG. 4  shows a perspective schematic view of a fourth preferred embodiment of a wheelchair according to the invention. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
     FIG. 1  shows a front view of a first preferred embodiment of a wheelchair  1  according to the invention. Wheelchair  1  comprises a frame  2  and a chair unit  3  connected to the frame. Chair unit  3  is herein provided with a seat  4 , two back supports  5  and two armrests  6 . The frame is connected to two small swivel wheels  7 , which swivel wheels  7  are rotatable about a horizontal axis and a vertical axis. The frame is also connected to two drive wheels  8  positioned adjacently of chair unit  3 . Drive wheels  8  are coupled by means of a wheel shaft  9  to a motor unit  10  for motorized driving of drive wheels  8 . Motor unit  10  can herein be operated by means of two operating handles  11  connected pivotally to wheel shaft  9 . In a situation of rest the operating handles  11  protrude in a substantially vertical direction relative to wheel shaft  9 . Operating handles  11  are here oriented such that a user of wheelchair  1  can reach and pivot the operating handles  11  relatively easily from a natural position and can thus operate wheelchair  1  relatively easily. Operating handles  11  are preferably pivotable substantially parallel to drive wheels  8 . In the shown exemplary embodiment each operating handle  11  is adapted to drive only an adjacent drive wheel  8 . The user can thus not only regulate the speed of wheelchair  1  by adjusting the degree of pivoting of operating handles  11 , but a change in direction of the wheelchair  1  can also be realized by pivoting one operating handle  11  further or less far than the other operating handle  11 . Operating handles  11  are each provided with a handgrip  12  in order to facilitate operation of handles  11  by a user. The maximum pivot of operating handles  11  is preferably bounded. By embodying motorized wheelchair  1  in the shown manner a user can control the wheelchair relatively easily and in a relatively natural posture, wherein both arms of the user are loaded only lightly though (substantially) uniformly. (More serious) physical problems, such as for instance severe fatigue or arm or back problems, can hereby be prevented or at least countered. 
     FIG. 2  shows a front view of a second preferred embodiment of a wheelchair  13  according to the invention. The construction of wheelchair  13  closely resembles the construction of the wheelchair  1  shown in  FIG. 1 . In  FIG. 2  the wheelchair is likewise provided with a motor unit  15  connected to support base  14  for driving two drive wheels  17  which are positioned laterally relative to a chair unit  16  connected to the support base. Motor unit  15  can now be operated by means of two push rims  19  pivotally connected to a wheel shaft  18  of drive wheels  17 . The speed of wheelchair  13  can be regulated by varying the degree of pivoting of push rims  19 . Pivoting of push rims  19  takes place in a direction toward chair unit  16  or away from chair unit  16 . The maximum pivot angle ∀ enclosed by the two extreme positions of each push rim  19  is bounded and is now shown (schematically) in  FIG. 2 . Push rims  19  can be locked in the shown position, wherein push rims  19  are oriented substantially parallel to drive wheels  17 , whereby manual driving is also made possible in this case. In determined situations, such as for instance indoors, a manual drive is usually recommended over a motorized drive. Motor unit  15  can be provided with two direct current direct drive motors (not shown) for direct (separate) driving of drive wheels  17 . The wheelchair  13  shown in  FIG. 2  also has the same advantages as wheelchair  1  shown in  FIG. 1 . 
     FIG. 3  shows a detail view of a-part of a third preferred embodiment of a wheelchair  20  according to the invention. The shown part of wheelchair  20  comprises a drive wheel  22  (corresponding to drive wheels  8 ,  17  of wheelchairs  1 ,  13  of  FIGS. 1 and 2 ) rotatable about a wheel shaft  21 . Drive wheel  22  is here constructed from a hub  23  positioned round wheel shaft  21  and a rim  24  positioned coaxially to hub  23 , wherein hub  23  and rim  24  are mutually connected by spokes  25 . Arranged around rim  24  is a conventional pneumatic tyre  26 . Drive wheel  22  is also provided with a drive push rim  27  connected to spokes  25  for manual—instead of motorized—driving of wheelchair  20 . Wheelchair  20  is further provided with an operating ring  29  connected to wheel shaft  21  via a number of springs  28  for the purpose of operating a motor  30  connected to wheel shaft  21 . Motor  30 , of which only a stator is shown here, is arranged between wheel shaft  21  and hub  23 . The relative rotation of operating ring  29  can be detected and serves as measure for the power to be transmitted by motor  30  to drive wheel  22 . The speed, both in forward and backward direction, can thus be regulated in relatively simple manner. 
     FIG. 4  shows a schematic perspective view of a fourth preferred embodiment of a wheelchair  31  according to the invention. Here only a single drive wheel  32  of wheelchair  31  is provided with a push rim  33 . Push rim  33  is herein provided with a handgrip  34  arranged round push rim  33 . Handgrip  34  is axially rotatable (A) and displaceable along push rim  33  (B), as shown respectively by arrows A and B. A motor (not shown) connected to drive wheel  32  can be operated by means of handgrip  34 . Because a twofold change in orientation of handgrip  34  is possible, a user can not only regulate the speed of wheelchair  31  by displacing handgrip  34  in direction B, but it is also possible to orient wheelchair  31  in a determined direction by rotating handgrip  34  axially in direction A. Wheelchair  31  can thus be operated in relatively simple yet efficient manner using only one hand. This can be particularly advantageous for users who are for instance paralysed on one side, or wherein one arm is incapacitated temporarily or otherwise. Wheelchair  31  is also provided with a conventional push rim  35  for manual instead of motorized driving of wheelchair  31 . 
   It will be apparent that the invention is not limited to the exemplary embodiments shown and described here, but that within the scope of the appended claims a large number of variants are possible which will be self-evident for a skilled person in this field.