Patent Publication Number: US-8118120-B2

Title: Power wheel chair

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation-in-part of U.S. patent application Ser. No. 12/454,751 filed May 22, 2009. Application Ser. No. 12/454,751 filed May 22, 2009 claims benefit of U.S. Patent Provisional application No. 61/128,556 filed May 22, 2008. All subject matter set forth in provisional application No. 61/128,556 filed May 22, 2008 and application Ser. No. 12/454,751 filed May 22, 2009 is hereby incorporated by reference into the present application as if fully set forth herein. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates to vehicles and more particularly to a power wheel chair having an improved motion control. 
     2. Description of the Related Art 
     Attendant operated patient transport vehicles may be characterized as either a manual wheelchair type or a powerchair personal mobility vehicle type with a joystick attendant control. Each of these transport vehicles has certain advantages and disadvantages. 
     A conventional manual wheelchair was not originally designed or intended to be pushed by an attendant or a caregiver. The handles for pushing a conventional manual wheelchair are poorly designed from an ergonomic standpoint for pushing by an attendant or a caregiver. Many attendants and caregivers incur back, neck, leg and carpal tunnel injuries from pushing a conventional manual wheelchair. Since many of the caregivers are spouses of an elderly disabled person, the spouses are at higher risk for heart attacks and accidental falls that can cause serious injury to both the attendant and wheelchair occupant. 
     The manual brakes of a conventional manual wheelchair are located on the front of the manual wheelchair and designed as parking brakes. Frequently, the attendant/caregiver fails to engage the parking brakes of a conventional manual wheelchair when the occupant is getting on or off of the conventional manual wheelchair that leads to further injuries. Furthermore, since the parking brakes are located on the front of the manual wheelchair, an attendant cannot engage the parking brakes while the wheelchair is in motion such as descending a ramp. 
     A powerchair personal mobility vehicle typically comprises a short frame having plural drive wheels and plural casters or idler wheels. The plural drive may be either front or the rear drive wheels with the caster or idler wheels providing the stability for the powerchair. The plural drive wheels are independently driven by plural electric motors. The plural electric motors are independently controlled by a control for independently driving the plural electric motors. 
     A joystick operates the control for controlling both the turning, speed, direction and braking of the powerchair. The turning of the powerchair is accomplished by a differential in speed between the plural independently driven electric motors. The control also enables one of the plural electric motors to have a reverse rotation relative to the other of the plural electric motors. The powerchair personal mobility vehicle is well suited for confined areas such as inside use due to the short frame and the superior turning radius of the plural independently driven electric motors. The short wheelbase provides a reduced turning radius for the personal mobility vehicle for negotiating smaller confined spaces indoors. 
     A scooter type personal mobility vehicle has been available for use by an occupant. A scooter personal mobility vehicle typically comprises an elongated frame having front wheel and plural rear wheels. The front wheel is pivotably mounted on the front portion of the elongated frame. A tiller and handlebar is provided for pivoting the front wheel for steering the personal mobility vehicle. The plural rear wheels are mounted on a common shaft driven by a single electric motor. The electric motor is controlled by a variable speed control and a forward and reverse located on the handlebar of the scooter. The scooter type personal mobility vehicle is well suited for unconfined areas such as outside use due to the superior ride of the elongated wheelbase of the scooter. The elongated wheelbase provides more stability and a better ride for the scooter personal mobility vehicle. 
     Typically, the cost of a powerchair personal mobility vehicle is greater than the cost of a scooter personal mobility vehicle due to the cost of plural electric motors in addition to the increased cost of a joystick operated dual-motor differential control relative to the single motor speed control of the scooter personal mobility vehicle. 
     Some powerchairs of the prior art were available with an optional primary or secondary joystick control for enabling an attendant or a caregiver to operate the powerchair from behind the seat of the powerchair. Unfortunately, it is difficult to operate a joystick of a powerchair vehicle while walking behind the seat of the powerchair. Because of the cost of a secondary joystick and the difficulty in operating the joystick control of the powerchair from behind the seat, the use of these optional attendant joysticks have not find widespread use in the art. 
     It is an object of the present invention to provide a power wheel chair that overcomes the inadequacies of the prior art vehicles and provides significant advancement in the patient transport art. 
     Another object of this invention is to provide a power wheel chair with maneuverability commensurate with a powerchair. 
     Another object of this invention is to provide a power wheel chair at cost significantly less than a powerchair. 
     Another object of this invention is to provide a power wheel chair with an improved motion control. 
     Another object of this invention is to provide a power wheel chair with an improved motion control that does not substantially increase the weight of the power wheel chair. 
     Another object of this invention is to provide a power wheel chair with an improved motion control that is easier to use while walking behind the powered vehicle. 
     Another object of this invention is to provide a power wheel chair with an improved motion control that is easier to use while walking along a side of the powered vehicle. 
     The foregoing has outlined some of the more pertinent objects of the present invention. These objects should be construed as being merely illustrative of some of the more prominent features and applications of the invention. Many other beneficial results can be obtained by modifying the invention within the scope of the invention. Accordingly other objects in a full understanding of the invention may be had by referring to the summary of the invention, the detailed description describing the preferred embodiment in addition to the scope of the invention defined by the claims taken in conjunction with the accompanying drawings. 
     SUMMARY OF THE INVENTION 
     The present invention is defined by the appended claims with specific embodiments being shown in the attached drawings. For the purpose of summarizing the invention, the invention relates to a power wheel chair having an improved motion control comprising a frame having a right frame section and a left frame section extending between a front frame end and a back frame end. A seat is mounted to the frame for transporting an occupant. A right and a left caster wheel is located in proximity to the front frame end adjacent to the right and left frame sections, respectively. A right and a left drive wheel are located in proximity to the rear frame end adjacent to the right and left frame sections, respectively. A motor drives the right and left drive wheels through a differential gearbox. A right and a left handle are connected to the right and left frame sections, respectively, for enabling an attendant to steer the power wheel chair. An electronic control has a control lever located in proximity to one of the right and left handles for enabling the attendant to control the speed and braking of the power wheel chair. 
     In a more specific example of the invention, the right and left handles extend generally backwardly from the back frame end. Preferably, the right and left handles extend generally horizontally and backwardly from the back frame end and include a right and a left hand gripping portion. The right and left handles operate in concert with the differential gearbox driving the right and left drive wheels for enabling an attendant to steer the power wheel chair. 
     In another example of the invention, a journal rotates one of the right and left handles about a generally vertical axis. A journal lock locks the one of the right and left handles about the generally vertical axis. The journal lock locks one of said right and left handles in generally parallel alignment with an axle driving the right and left drive wheels through the differential gearbox. In an alternate example, each of the right and left handles includes a vertical adjustment device for adjusting a vertical position of the right and left handles. A right and a left adjustment lock secures the right and left handles in a vertical position. 
     In still another example of the invention, the invention relates to a battery cassette receiver secured to the frame. The battery cassette receiver has cassette receiver contacts connected to the frame. A battery cassette has a battery connected to battery cassette contacts. The battery cassette is insertable into the battery cassette receiver for interconnecting the battery cassette contacts with the cassette receiver contacts for powering the power wheel chair. 
     In a further example of the invention, a remote battery cassette receiver is located remote from the power wheel chair. The remote battery cassette receiver has remote receiver cassette contacts connected to a battery charger. The battery cassette is insertable into the remote battery cassette receiver for interconnecting the battery cassette contacts with the remote cassette receiver contacts for charging the battery. 
     The foregoing has outlined rather broadly the more pertinent and important features of the present invention in order that the detailed description that follows may be better understood so that the present contribution to the art can be more fully appreciated. Additional features of the invention will be described hereinafter which form the subject of the claims of the invention. It should be appreciated by those skilled in the art that the conception and the specific embodiments disclosed may be readily utilized as a basis for modifying or designing other structures for carrying out the same purposes of the present invention. It should also be realized by those skilled in the art that such equivalent constructions do not depart from the spirit and scope of the invention as set forth in the appended claims. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       For a fuller understanding of the nature and objects of the invention, reference should be made to the following detailed description taken in connection with the accompanying drawings in which: 
         FIG. 1  is a side view of a power wheel chair incorporating an improved motion control of the present invention; 
         FIG. 2  is a front view of  FIG. 1 ; 
         FIG. 3  is a top view of  FIG. 1 ; 
         FIG. 4  is a bottom view of  FIG. 1 ; 
         FIG. 5  is a rear view of  FIG. 1 ; 
         FIG. 6  is an enlarged isometric view of a frame coupling for connecting a steering and control bar to the power wheel chair; 
         FIG. 7  is a side view similar to  FIG. 1  illustrating an occupant seated in the power wheel chair with an attendant controlling the power wheel chair; 
         FIG. 7A  is a side view similar to  FIG. 7  illustrating the tilting of the power wheel chair with the steering bar for overcoming an elevated obstruction shown as a curb; 
         FIG. 8  is a top view of the power wheel chair of  FIGS. 1-7  illustrating equal forces applied to the steering bar of the power wheel chair for directing the personal mobility vehicle in a straight direction; 
         FIG. 9  is a top view similar to  FIG. 8  illustrating unequal forces applied to the steering bar of the power wheel chair for turning the power wheel chair; 
         FIG. 10  is a top view similar to  FIG. 9  illustrating continued unequal forces applied to the steering bar of the power wheel chair for continued turning the power wheel chair; 
         FIG. 11  is a side view of a second embodiment of a power wheel chair incorporating an improved motion control of the present invention; 
         FIG. 12  is a side view of a third embodiment of a power wheel chair incorporating an improved motion control of the present invention; 
         FIG. 13  is a front view of  FIG. 12 ; 
         FIG. 14  is a top view of  FIG. 12   
         FIG. 15  is an enlarged isometric view of a caster coupling for connecting a tiller to a caster of the power wheel chair; 
         FIG. 16  is a side view similar to  FIG. 12  illustrating an occupant seated in the power wheel chair with the occupant controlling the power wheel chair; 
         FIG. 17  is a top view of the power wheel chair of  FIGS. 12-16  illustrating neutral force applied to the tiller of the power wheel chair for directing the power wheel chair in a straight direction; 
         FIG. 18  is a top view similar to  FIG. 17  illustrating a rotational force applied to the tiller of the power wheel chair for turning the power wheel chair; and 
         FIG. 19  is a top view similar to  FIG. 18  illustrating a continued rotational force applied to the tiller of the power wheel chair for continued turning the power wheel chair. 
         FIG. 20  is a side view of a fourth embodiment of a power wheel chair incorporating an improved motion control of the present invention; 
         FIG. 21  is a top view of  FIG. 20 ; 
         FIG. 22  is a rear view of  FIG. 20 ; 
         FIG. 23  is a rear view similar to  FIG. 22  with a battery cassette removed; 
         FIG. 24  is an enlarged view of the removed battery cassette positioned adjacent to a remote charging assembly; 
         FIG. 25  is an enlarged view of the removed battery cassette being charged by the remote charging assembly; 
         FIG. 26  is an enlarged view along line  26 - 26  in  FIG. 23 ; 
         FIG. 27  is an enlarged view along line  27 - 27  in  FIG. 23  illustrating the right handle of the power wheel chair located in first rotational position; 
         FIG. 28  is a top view similar to  FIG. 27  illustrating the right handle of the power wheel chair located in second rotational position; 
         FIG. 29  is a top view similar to  FIG. 27  illustrating the right handle of the power wheel chair located in third rotational position; 
         FIG. 30  is a top view similar to  FIG. 27  illustrating the right handle of the power wheel chair located in fourth rotational position; 
         FIG. 31  is a sectional view along line  31 - 31  in  FIG. 27 ; 
         FIG. 32  is a sectional view similar to  FIG. 31  illustrating an alternate embodiment of the invention incorporating a right vertical handle adjustment device with the right handle located in a lowered position; 
         FIG. 33  is a view similar to  FIG. 32  illustrating the right handle located in a raised position; 
         FIG. 34  is a top view of the power wheel chair of  FIGS. 21-23  illustrating neutral force applied to the right and left handles of the power wheel chair for directing the power wheel chair in a straight forward direction; 
         FIG. 35  is a top view similar to  FIG. 34  illustrating a rotational force applied to the right and left handles of the power wheel chair for turning the power wheel chair; 
         FIG. 36  is a top view of the power wheel chair of  FIGS. 21-23  illustrating neutral force applied to the right and left handles of the power wheel chair for directing the power wheel chair in a straight reverse direction; 
         FIG. 37  is a top view of the power wheel chair of  FIGS. 21-23  illustrating rotational force applied to the right and left handles of the power wheel chair for directing the power wheel chair in a turning reverse direction; 
         FIG. 38  is a top view of the power wheel chair of  FIGS. 21-23  and  29  illustrating neutral force applied to the right handles and the right armrest of the power wheel chair for directing the power wheel chair in a straight forward direction; and 
         FIG. 39  is a top view of the power wheel chair of  FIGS. 21-23  and  29  illustrating rotational force applied to the right handles and the right armrest of the power wheel chair for directing the power wheel chair in a turning forward direction. 
     
    
    
     Similar reference characters refer to similar parts throughout the several Figures of the drawings. 
     DETAILED DISCUSSION 
       FIGS. 1-5  are various views of a power wheel chair  5  incorporating an improved motion control  10  of the present invention. The power wheel chair  5  comprises a frame  20  extending between a first frame end  21  and a second frame end  22 . The first frame end  21  and the second frame end  22  define an intermediate frame portion  23  of the frame  20 . The frame  20  of the power wheel chair  5  is covered by a covering  25  for overlaying interior portions of the power wheel chair  5  and for enhancing the attractiveness of the power wheel chair  5 . 
     As best shown in  FIG. 4 , the power wheel chair  5  comprises a drive wheel assembly  30  comprises a right and a left drive wheel  31  and  32  located in proximity to the second end  22  of the frame  20 . A single drive motor  34  drives the right and left drive wheels  31  and  32  through a differential gearbox  36 . The differential gearbox  36  enables one of the right and left drive wheels  31  and  32  to rotate faster than the other of the right and left drive wheels  31  and  32  during a turn of the power wheel chair  5  as should be well known to those skilled in the art. 
     A caster wheel assembly  40  is located in proximity to the first frame end  21  of the frame  20 . The caster wheel assembly  40  comprises a right and a left caster wheel  41  and  42 . The right and left caster wheels  41  and  42  are shown as right and left caster wheels mounted by swivels to the first frame end  21  of the frame  20 . 
     A pedestal  50  extends between a lower end  51  and an upper end  52  in a substantially vertical orientation. The lower end  51  of the pedestal  50  is secured to the intermediate frame end  33  of the frame  20 . An upper end  52  of the pedestal  50  extends upwardly for supporting a chair assembly  60 . The upper end  52  of the pedestal  50  defines an internal aperture  55  within the pedestal  50   
     The chair assembly  60  comprises a chair portion  61  and a backrest portion  62 . In this example, the backrest portion  62  is pivotally mounted to the chair portion  61  by a pivot  63  for accommodating for the size and comfort of an occupant. 
     The chair assembly  60  is rotatably mounted on the pedestal  50  with the rotation of the chair assembly  60  being controlled by a lever  64 . The chair assembly  60  includes a rotation shaft  65  receivable within the internal aperture  65  of the pedestal  50  for rotatably mounting chair assembly  60  on the pedestal  50 . The rotation of the chair assembly  60  facilitates the ingress and egress of an occupant  70  from the power wheel chair  5 . Plural armrests  66  and  67  are secured to the chair portion  61  of the chair assembly  60 . A rotational chair assembly  60  suitable for use with the present invention is more fully set forth in U.S. Pat. No. 6,361,111 which is incorporated by reference into the present application. 
     A footrest assembly  80  is located on the first end  21  of the frame  20 . The footrest assembly  80  comprises a footrest base  81  secured to the first end  21  of the frame  20 . A footrest plate  82  mounted to the footrest base  81  by a pivot  83  enabling the footrest plate  82  to be pivoted between a operative position, wherein the first footrest plate  82  is disposed in a generally horizontal position as shown in  FIG. 1  and an inoperative position wherein the footrest plate  82  is disposed in a generally vertical position (not shown). The footrest plate  82  provides a footrest for the occupant  70 . 
     A steering bar  90  is secured to the power wheel chair  5  for controlling the turning direction and speed of the power wheel chair  5 . In this embodiment, the steering bar  90  comprises a right end  91  and a left end  92  defining a handlebar  94 . An upstanding portion  100  extends between a lower end  101  and an upper end  102 . The handlebar  94  is secured to the upper end  102  of the upstanding portion  100  with the right and left ends  91  and  92  extending outwardly therefrom. The lower end  101  of the upstanding portion  100  is secured to a frame mounting  110  through a coupling  120 . The right and left end  91  and  92  of the handlebar  94  are fixed relative to the frame  20  for enabling the attendant  72  to turn the power wheel chair  5 . 
     An electronic control  130  includes a control console  132  having a control lever  134  located on the steering bar  90  for controlling the speed and direction of the drive motor  34 . Preferably, the electronic control  130  incorporates a forward direction speed function, a reverse direction speed function, as well as, a braking function of the drive motor  34 . 
     The frame mounting  110  comprises a first and a second attachment member  111  and  112  secured to the second end  22  of the frame  20 . An intermediate member  113  interconnects the first and second attachment members  111  and  112 . The intermediate member  113  supports the coupling  120  for connecting the steering bar  90  to the power wheel chair  5 . 
     The coupling  120  comprises a lower coupling portion  121  and an upper coupling portion  122 . The lower coupling portion  121  is secured to the intermediate member  113  of the frame mounting  110  whereas the upper coupling portion  122  is defined in the lower end  101  of the upstanding member  100 . 
       FIG. 6  is an enlarged isometric view of the coupling  120  for connecting the steering bar  90  to the power wheel chair  5 . In this example, the lower coupling portion  121  comprises a keyed aperture  124  whereas the upper coupling portion  122  comprises a keyed insert  126 . The keyed insert  126  is insertable into the keyed aperture  124  for connecting the steering bar  90  to the power wheel chair  5 . Although the coupling  120  has been shown as a keyed aperture  124  and a keyed insert  126 , it should be appreciated by those skilled in the art that various types of coupling may be used connecting the steering bar  90  to the power wheel chair  5 . 
       FIG. 7  is a side view similar to  FIG. 1  illustrating an occupant  70  seated in the power wheel chair  5  with an attendant  72  controlling the speed, direction and braking of the power wheel chair  5 . 
       FIG. 7A  is a side view similar to  FIG. 7  illustrating the tilting of the power wheel chair  5  with the steering bar  90  for overcoming an elevated obstruction  75  such as a curb and the like. The attendant  72  push downwardly on the steering bar  90  for rotating the power patient transport vehicle  5  about the drive wheels  31  and  32 . The rotation of the power patient transport vehicle  5  about the drive wheels  31  and  32  raises the caster wheels  41  and  42  above the height of the elevated obstruction  75 . Once the caster wheels  41  and  42  have been raised above the level of the elevated obstruction  75 , the power wheel chair  5  may be powered over the elevated obstruction  75  through the powered drive wheels  31  and  32 . Rear caster wheels  141  and  142  are provided for limiting the rotation of the power patient transport vehicle  5  about the drive wheels  31  and  32 . In one example, rear caster wheels  141  and  142  positions 1 inch above a ground surface permits a raising of the caster wheels  41  and  42  of 3 inches above a ground surface. This type of overcoming an elevated obstruction  75  is impossible for either a scooter or a powerchair personal mobility vehicle without significant discomfort for the occupant. 
       FIG. 8  is a top view of the power wheel chair  5  of  FIGS. 1-7  illustrating equal forces applied to the handlebar  94  of the power wheel chair  5  by the attendant  72  for directing the power wheel chair  5  in a straight direction. 
       FIG. 9  is a top view similar to  FIG. 8  illustrating unequal forces applied to the handlebar  94  of the power wheel chair  5  by the attendant  72  for turning the power wheel chair  5 . 
       FIG. 10  is a top view similar to  FIG. 9  illustrating continued unequal forces applied to the handlebar  94  of the power wheel chair  5  by the attendant  72  for continued turning the power wheel chair  5 . 
       FIG. 11  is a side view of a second embodiment of a power wheel chair  5 A incorporating an improved motion control  10 A of the present invention. In this example, the power wheel chair  5 A comprises a frame  20 A extending between a first frame end  21 A and a second frame end  22 A. A drive wheel assembly  30 A comprises a right and left drive wheel  31 A and  32 A located in proximity to the second end  22 A of the frame  20 . A caster wheel assembly  40 A comprising a right and a left caster wheel  41 A and  42 A is located in proximity to the first frame end  21 A of the frame  20 A. The steering bar  90 A is secured to in proximity to the first end  21 A of the frame  20 A. 
     The steering bar  90 A is mounted to the first frame end  21 A of the frame  20 A through an upstanding portion  100 A and a frame mounting  110 A through a coupling  120 A in a manner similar to  FIGS. 1-6 . The second embodiment of a power wheel chair  5 A provides a front wheel drive in contrast to the rear wheel drive shown in  FIGS. 1-6 . 
     The front wheel drive power wheel chair  5 A shown in  FIG. 11  is shown in  FIG. 1 . In addition, the front wheel drive power wheel chair  5 A has more traction and accommodates larger obstacles such as larger curbs and larger bumps than the rear wheel drive power wheel chair  5 . In contrast, the rear wheel drive power wheel chair  5  has better maneuverability than a front wheel drive power wheel chair  5 A. Accordingly, the front wheel drive power wheel chair  5 A is generally more suitable for outdoor use whereas the rear wheel drive power wheel chair  5  is generally more suitable for indoor use. 
       FIGS. 12-14  are various views of a third embodiment of a power wheel chair  5 B incorporating an improved motion control  10 B of the present invention. The power wheel chair  5 B comprises a frame  20 B extending between a first frame end  21 B and a second frame end  22 B. A drive wheel assembly  30 B comprises a right and a left drive wheel  31 B and  32 B located in proximity to the second end  22 B of the frame  20 B. A single drive motor  34 B drives the right and left drive wheels  31 B and  32 B through a differential gearbox  36 B in a manner similar to  FIGS. 1-6 . A caster wheel assembly  40 B is located in proximity to the first frame end  21 B of the frame  20 B. The caster wheel assembly  40 B comprises a right and a left caster wheel  41 B and  42 B. The right and left caster wheels  41 B and  42 B are shown as right and left caster wheels mounted by swivels to the first frame end  21 B of the frame  20 B. 
     A steering bar  90 B is secured to the power wheel chair  5 B for controlling the power wheel chair  5 B. In this embodiment, the steering bar  90 B comprises a hand gripping portion  91 B defining a tiller  96 B. An upstanding portion  100 B extends between a lower end  101 B and an upper end  102 B. The tiller  96 B is secured to the upper end  102 B of the upstanding portion  100 B with the hand gripping portion  91 B extending outwardly therefrom. The lower end  101 B of the upstanding portion  100 B is secured one of the right and left casters  41 B and  42 B through a coupling  120 B. The tiller  96 B is fixed relative to the one of the right and left casters  41 B and  42 B for enabling the occupant  70 B to turn the power wheel chair  5 B. 
     An electronic control  130 B includes a control console  132 B having a control lever  134 B located on the tiller  96 B for controlling the speed, direction and braking of the drive motor  34 B. Preferably, the electronic control  130  incorporates a forward direction speed function, a reverse direction speed function as well as a braking function of the drive motor  34 B. 
       FIG. 15  is an enlarged isometric view the right caster wheels  41 B and a caster coupling  120 B for connecting the steering bar  90 B to the right caster wheels  41 B. The caster coupling  120 B comprises a lower coupling portion  121 B and an upper coupling portion  122 B. The lower coupling portion  121 B is secured to the right caster wheels  41 B whereas the upper coupling portion  122 B is defined in the lower end  101 B of the upstanding member  100 B. 
     In this example, the lower coupling portion  121 B comprises a keyed aperture  124 B whereas the upper coupling portion  122 B comprises a keyed insert  126 B. The keyed insert  126 B is insertable into the keyed aperture  124 B for connecting the steering bar  90 B to the power wheel chair  5 B. 
       FIG. 16  is a side view similar to  FIG. 12  illustrating an occupant  70 B seated in the power wheel chair  5 B with the occupant  70 B controlling the power wheel chair  5 B. 
       FIG. 17  is a top view of the power wheel chair  5 B of  FIGS. 12-16  illustrating neutral force applied to the steering bar  90 B of the power wheel chair  5 B by the occupant  70 B for directing the power wheel chair  5 B in a straight direction. 
       FIG. 18  is a top view similar to  FIG. 17  illustrating a rotational force applied to the steering bar  90 B of the power wheel chair  5 B by the occupant  70 B for turning the power wheel chair  5 B. 
       FIG. 19  is a top view similar to  FIG. 18  illustrating a continued rotational force applied to the steering bar  90 B of the power wheel chair  5 B by the occupant  70 B for continued turning the power wheel chair  5 B. 
       FIGS. 20-23  are various views of a power wheel chair  205  incorporating an improved motion control  210  of the present invention. The power wheel chair  205  comprises a frame  220  extending between a front frame end  221  and a back frame end  222 . The front frame end  221  and the back frame end  222  define an intermediate frame area  223  of the frame  220 . The frame  210  has a right frame section  225  and a left frame section  226  extending between the front frame end  221  and the back frame end  222 . The frame  220  includes a right and a left upstanding portion  227  and  228 . 
     The power wheel chair  205  comprises a drive wheel assembly  230  having a right and a left drive wheel  231  and  232  located adjacent to the right and left frame sections  225  and  226  and in proximity to the back frame end  222  of the frame  220 . The right and left drive wheels  231  and  232  are mounted on right and left axles  233  and  234 . A single drive motor  235  drives the right and left drive wheels  231  and  232  through a differential gearbox  236 . The differential gearbox  236  enables one of the right and left drive wheels  231  and  232  to rotate faster than the other of the right and left drive wheels  231  and  232  during a turn of the power wheel chair  205  as should be well known to those skilled in the differential gearbox art. 
     A caster wheel assembly  240  is located in proximity to the front frame end  221  of the frame  220 . The caster wheel assembly  240  comprises a right and a left caster wheel  241  and  242  mounted in axles  243  and  244  located adjacent to the right and left frame sections  225  and  226 . A right and a left swivel  245  and  246  rotatably mount the right and left caster wheels  241  and  242  to the front frame end  221  of the frame  220 . 
     The chair assembly  260  comprises a chair portion  261  and a backrest portion  262  for accommodating an occupant as previously shown. The chair assembly  260  includes a right and a left armrest  263  and  264  are secured to the chair portion  261  of the chair assembly  260 . 
     A footrest assembly  280  is located on the front end  221  of the frame  220 . The footrest assembly  280  comprises a right and a left footrest base  281  and  282  secured to the first end  221  of the frame  220 . A right and a left footrest plate  283  and  284  are mounted to the right and left footrest bases  281  and  282  by right and left pivots  285  and  286  enabling the right and left footrest plates  283  and  284  to be pivoted between a operative position, wherein the right and left footrest plates  283  and  284  are disposed in an operative position as shown in  FIGS. 20 and 21  and an inoperative position wherein the right and left footrest plates  283  and  284  are disposed in a generally vertical position (not shown). The right and left footrest plates  283  and  284  provide a footrest for the occupant (not shown). 
     A steering handle assembly  290  is secured to the power wheel chair  205  for controlling the turning direction and speed of the power wheel chair  205 . In this embodiment, the steering handle assembly  290  comprises a right handle  291  and a left handle  292  connected to the right and left frame sections  225  and  226 , respectively. The right and left handles extend generally backwardly from the back frame end  222 . Preferably, the right and left handles  291  and  292  extend generally horizontally and backwardly from the back frame end  222  and include a right and a left hand gripping portion  293  and  294 . The right and left handles  291  and  292  operate in concert with the differential gearbox  236  driving the right and left drive wheels  231  and  232  for enabling an attendant as previously shown to steer the power wheel chair  205 . 
       FIG. 22  is rear view of the power wheel chair  205  of  FIGS. 20 and 21 . A battery assembly  300  is secured to the frame  220 . The battery assembly  300  comprises a battery cassette receiver  302  having cassette receiver contacts  304 . A battery cassette  305  has a battery  306  connected to battery cassette contacts  308 . The battery cassette  305  is insertable into the battery cassette receiver  302  for interconnecting the battery cassette contacts  308  with the cassette receiver contacts  304  for powering the power wheel chair  205 . 
       FIG. 23  is rear view of the power wheel chair  205  similar to  FIG. 22  with the battery cassette  305  removed from the power wheel chair  205 . The battery cassette  305  is removable from the battery cassette receiver  302  for charging the battery  306  at a remote location from the power wheel chair  205 . 
       FIG. 24  is an enlarged view of the removed battery cassette  305  positioned adjacent to a remote charging assembly  310 . The remote charging assembly  310  comprises a remote battery cassette receiver  312  having remote receiver cassette contacts  314  connected to a conventional battery charger (not shown). 
       FIG. 25  is an enlarged view of the removed battery cassette  305  being charged by a remote charger. The battery cassette  305  is insertable into the remote battery cassette receiver  312  for interconnecting the battery cassette contacts  308  with the remote cassette receiver contacts  314  for charging the battery  306 . 
       FIGS. 26 and 27  are enlarged views of  FIG. 23  illustrating an electronic control  330  for controlling the drive motor  235 . The electronic control  330  includes a control console  332  having a control lever  334  and switches  336  located on the right handle  291  for controlling the speed and direction of the drive motor  235 . Preferably, the electronic control  230  incorporates a forward direction speed function, a reverse direction speed function, as well as, a braking function of the drive motor  235 . 
       FIG. 27  is an enlarged view along line  27 - 27  in  FIG. 23  illustrating the right handle  291  of the power wheel chair  205  located in first rotational position. The first rotational position aligns the right handle  291  generally backwardly and perpendicular to the right axles  233 . 
       FIG. 28  is a top view similar to  FIG. 27  illustrating the right handle  291  of the power wheel chair  205  located in second rotational position. The second rotational position aligns the right handle  291  generally forwardly and perpendicular to the right axles  233 . 
       FIG. 29  is a top view similar to  FIG. 27  illustrating the right handle  291  of the power wheel chair  205  located in third rotational position. The third rotational position aligns the right handle  291  generally outwardly and parallel to the right axles  233 . 
       FIG. 30  is a top view similar to  FIG. 27  illustrating the right handle  291  of the power wheel chair  205  located in fourth rotational position. The fourth rotational position aligns the right handle  291  generally inwardly and parallel to the right axles  233 . 
       FIG. 31  is a sectional view along line  31 - 31  in  FIG. 27  illustrating a journal assembly  340 . The journal assembly  340  comprises an internal rotator  342  rotatably received with the upstanding portion  227  of the frame  220 . The internal rotator  342  includes an outward extending disk  344  extending outwardly from the internal rotator  342 . The internal rotator  342  is secured to the right handle  291  by a fastener  346 . The outward extending disk  344  includes a plurality depressions  348 . 
     The journal assembly  340  comprises a disk chamber  350  secure to the upstanding portion  227  of the frame  220 . The disk chamber  350  receives the outward extending disk  344  for rotation within the disk chamber  350 . The disk chamber  350  includes a pin  352  biased into engagement with the outward extending disk  344  by a spring  354 . A pull ring  356  is secured to the pin  352 . 
     The journal assembly  340  locks the rotation position of the right handle  291  in one of the rotational position shown in  FIGS. 27-30 . The journal assembly  340  locks the rotation position of the right handle  291  when the pin  352  engages one of the plurality depressions  348  with the outward extending disk  344 . The pull ring  356  enables an operator to withdrawal of the pin  352  from the depressions  348  for enabling rotation of the right handle  291  between the rotational position shown in  FIGS. 27-30 . 
       FIG. 32  is a sectional view similar to  FIG. 31  illustrating an alternate embodiment of the invention incorporating a vertical handle adjustment device  360 . In this example, the vertical handle adjustment device  360  comprises a right vertical handle adjustment device  362  incorporated between the right upstanding portion  227  and the right handle  291 . It should be appreciated by those skilled in the art that a left vertical handle adjustment device (not shown) may be incorporated between the left upstanding portion  228  and the left handle  292 . 
     The right vertical handle adjustment device  361  comprising an adjustment sleeve  362  having an internal diameter to slidably engage with the upstanding portion  227 . The adjustment sleeve  362  extends between an upper end  364  and a lower end  365 . The upper end of the adjustment sleeve  362  is secured to the disk chamber  350 . The lower end  365  of the adjustment sleeve  362  includes a slot  366 . 
     The vertical adjustment device  361  includes a clamping lock  370  for securing the right vertical handle adjustment device  361  in a lowered position as shown in  FIG. 32  and a raised position as shown in  FIG. 33 . The clamping lock  370  comprises a compression ring  371  having a threaded stud  372  extending through ends of the compression ring  371 . An adjustment nut  374  is located on one end of the threaded stud  372  whereas a cam lever  376  is located on the other end of the threaded stud  372 . 
       FIG. 32  illustrates the right handle  291  located in the lowered position. The cam lever  376  located in a locked position for securing the right vertical handle adjustment device  361  in the lowered position. The cam lever  376  contracts the compression ring  371  to reduce the diameter of the lower end  365  of the adjustment sleeve  362  in proximity to the slot  366  to secure the adjustment sleeve  362  to the upstanding portion  227 . 
       FIG. 33  is a view similar to  FIG. 32  illustrating the right handle  291  located in a raised position. The cam lever  376  located in an unlocked position for enabling the right vertical handle adjustment device  361  to be raised from the lowered position as shown in  FIG. 32  to the raised position as shown in  FIG. 32 . The cam lever  376  is moved into the locked position when the right handle  291  is positioned at the desired vertical height. 
       FIG. 34  is a top view of the power wheel chair of  FIGS. 21-23  illustrating neutral force applied to the right and left handles  291  and  292  of the power wheel chair  205  for directing the power wheel chair  205  in a straight forward direction. 
       FIG. 35  is a top view similar to  FIG. 31  illustrating a rotational force applied to the right and left handles  291  and  292  of the power wheel chair  205  for turning the power wheel chair  205 . The right and left handles  291  and  292  operate in concert with the differential gearbox  236  for turning the power wheel chair  205 . 
       FIG. 36  is a top view of the power wheel chair of  FIGS. 21-23  illustrating neutral force applied to the right and left handles  291  and  292  of the power wheel chair  205  for directing the power wheel chair  205  in a straight reverse direction. 
       FIG. 37  is a top view of the power wheel chair of  FIGS. 21-23  illustrating rotational force applied to the right and left handles  291  and  292  of the power wheel chair  205  for directing the power wheel chair  205  in a turning reverse direction. The right and left handles  291  and  292  operate in concert with the differential gearbox  236  for turning the power wheel chair  205 . 
       FIG. 38  is a top view of the power wheel chair of  FIGS. 21-23  and  29  illustrating neutral force applied to the right handles  291  and the right armrest  263  of the power wheel chair  205  for directing the power wheel chair  205  in a forward direction. This configuration enables an attendant (not shown) to operate the power wheel chair  205  adjacent to the right frame section  225  or the right side to the power wheel chair  205 . 
       FIG. 39  is a top view of the power wheel chair of  FIGS. 21-23  and  29  illustrating rotational force applied to the right handles  291  and the right armrest  263  of the power wheel chair  205  for directing the power wheel chair  205  in a turning forward direction. The right and left handles  291  and  292  operate in concert with the differential gearbox  236  for turning the power wheel chair  205 . 
     It should be appreciated by those skilled in the art that a power wheel chair may be fashioned to provide the attendant controlled power wheel chair  5  as shown in  FIGS. 1-11  as well as the occupant controlled power wheel chair  5 B as shown in  FIGS. 12-19 . 
     The present disclosure includes that contained in the appended claims as well as that of the foregoing description. Although this invention has been described in its preferred form with a certain degree of particularity, it is understood that the present disclosure of the preferred form has been made only by way of example and that numerous changes in the details of construction and the combination and arrangement of parts may be resorted to without departing from the spirit and scope of the invention.