Patent Publication Number: US-8113305-B1

Title: Powered patient transport vehicle

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application 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 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 powered patient transport vehicle having an improved motion control. 
     2. Background of the Invention 
     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 powered patient transport vehicle 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 powered patient transport vehicle with maneuverability commensurate with a powerchair. 
     Another object of this invention is to provide a powered patient transport vehicle at cost significantly less than a powerchair. 
     Another object of this invention is to provide a powered patient transport vehicle with an improved motion control. 
     Another object of this invention is to provide a powered patient transport vehicle with an improved motion control that does not substantially increase the weight of the powered patient transport vehicle. 
     Another object of this invention is to provide a powered patient transport vehicle 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 powered patient transport vehicle with a motion control that may be controlled by the occupant of the powered patient transport 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 and the detailed description describing the preferred embodiment of the invention. 
     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 powered patient transport vehicle having an improved motion control comprising a frame extending between a first end and a second end. A first and a second caster wheel are located in proximity to the first end of the frame. A first and a second drive wheel are located in proximity to the second end of the frame. A motor drives the first and second drive wheels through a differential gearbox. An electronic control has a control lever for controlling the speed, direction and breaking of the motor. A seat is mounted to the frame for transporting an occupant. A steering bar is coupled to the powered patient transport vehicle for steering the powered patient transport vehicle. 
     In another example of the invention, the invention relates to a powered patient transport vehicle having an improved motion control comprising a frame extending between a first end and a second end. A first and a second caster wheel are located in proximity to the first end of the frame. A first and a second drive wheel are located in proximity to the second end of the frame. A motor drives the first and second drive wheels through a differential gearbox. A control regulates the speed, direction and braking of the motor. A seat is mounted to the frame for transporting an occupant. A steering bar is secured to the frame for enabling an attendant to control and steer the powered patient transport vehicle with the occupant therein. 
     In still another example of the invention, the invention relates to a powered patient transport vehicle having an improved motion control comprising a frame extending between a first end and a second end. A first and a second caster wheel are located in proximity to the first end of the frame. A first and a second drive wheel are located in proximity to the second end of the frame. A motor drives the first and second drive wheels through a differential gearbox. A control regulates the speed and direction of the motor. A seat is mounted to the frame for transporting an occupant. A tiller is secured to one of the first and second caster wheels for enabling the occupant to operate the control and to turn the powered patient transport vehicle. 
     In a further example of the invention, a steering bar comprises an upstanding portion extending between a lower end and an upper end with the lower end of the upstanding portion being secured to the powered patient transport vehicle. A handlebar secured to the upper end of the upstanding portion for enabling an attendant to control and steer the powered patient transport vehicle with the occupant therein. The upstanding portion and the handlebar enable an attendant to pull on the handlebar for rotating the power patient transport vehicle about the first and second drive wheels to raise the first and second caster wheels to overcome an elevated obstruction. 
     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 matter 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. 
    
    
     
       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 powered patient transport vehicle 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 powered patient transport vehicle; 
         FIG. 7  is a side view similar to  FIG. 1  illustrating an occupant seated in the powered patient transport vehicle with an attendant controlling the powered patient transport vehicle; 
         FIG. 7A  is a side view similar to  FIG. 7  illustrating the tilting of the powered patient transport vehicle with the steering bar for overcoming an elevated obstruction shown as a curb; 
         FIG. 8  is a top view of the powered patient transport vehicle of  FIGS. 1-7  illustrating equal forces applied to the steering bar of the powered patient transport vehicle 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 powered patient transport vehicle for turning the powered patient transport vehicle; 
         FIG. 10  is a top view similar to  FIG. 9  illustrating continued unequal forces applied to the steering bar of the powered patient transport vehicle for continued turning the powered patient transport vehicle; 
         FIG. 11  is a side view of a second embodiment of a powered patient transport vehicle incorporating an improved motion control of the present invention; 
         FIG. 12  is a side view of a third embodiment of a powered patient transport vehicle 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 powered patient transport vehicle; 
         FIG. 16  is a side view similar to  FIG. 12  illustrating an occupant seated in the powered patient transport vehicle with the occupant controlling the powered patient transport vehicle; 
         FIG. 17  is a top view of the powered patient transport vehicle of  FIGS. 12-16  illustrating neutral force applied to the tiller of the powered patient transport vehicle for directing the powered patient transport vehicle in a straight direction; 
         FIG. 18  is a top view similar to  FIG. 17  illustrating a rotational force applied to the tiller of the powered patient transport vehicle for turning the powered patient transport vehicle; and 
         FIG. 19  is a top view similar to  FIG. 18  illustrating a continued rotational force applied to the tiller of the powered patient transport vehicle for continued turning the powered patient transport vehicle. 
     
    
    
     Similar reference characters refer to similar parts throughout the several Figures of the drawings. 
     DETAILED DISCUSSION 
       FIGS. 1-5  are various views of a powered patient transport vehicle  5  incorporating an improved motion control  10  of the present invention. The powered patient transport vehicle  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 powered patient transport vehicle  5  is covered by a covering  25  for overlaying interior portions of the powered patient transport vehicle  5  and for enhancing the attractiveness of the powered patient transport vehicle  5 . 
     As best shown in  FIG. 4 , the powered patient transport vehicle  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 powered patient transport vehicle  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 powered patient transport vehicle  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 powered patient transport vehicle  5  for controlling the turning direction and speed of the powered patient transport vehicle  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  1111  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 powered patient transport vehicle  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 powered patient transport vehicle  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 powered patient transport vehicle  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 powered patient transport vehicle  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 powered patient transport vehicle  5 . 
       FIG. 7  is a side view similar to  FIG. 1  illustrating an occupant  70  seated in the powered patient transport vehicle  5  with an attendant  72  controlling the speed, direction and braking of the powered patient transport vehicle  5 . 
       FIG. 7A  is a side view similar to  FIG. 7  illustrating the tilting of the powered patient transport vehicle  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 powered patient transport vehicle  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 powered patient transport vehicle  5  of  FIGS. 1-7  illustrating equal forces applied to the handlebar  94  of the powered patient transport vehicle  5  by the attendant  72  for directing the powered patient transport vehicle  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 powered patient transport vehicle  5  by the attendant  72  for turning the powered patient transport vehicle  5 . 
       FIG. 10  is a top view similar to  FIG. 9  illustrating continued unequal forces applied to the handlebar  94  of the powered patient transport vehicle  5  by the attendant  72  for continued turning the powered patient transport vehicle  5 . 
       FIG. 11  is a side view of a second embodiment of a powered patient transport vehicle  5 A incorporating an improved motion control  10 A of the present invention. In this example, the powered patient transport vehicle  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 powered patient transport vehicle  5 A provides a front wheel drive in contrast to the rear wheel drive shown in  FIGS. 1-6 . 
     The front wheel drive powered patient transport vehicle  5 A shown in  FIG. 11  is shown in  FIG. 1 . In addition, the front wheel drive powered patient transport vehicle  5 A has more traction and accommodates larger obstacles such as larger curbs and larger bumps than the rear wheel drive powered patient transport vehicle  5 . In contrast, the rear wheel drive powered patient transport vehicle  5  has better maneuverability than a front wheel drive powered patient transport vehicle  5 A. Accordingly, the front wheel drive powered patient transport vehicle  5 A is generally more suitable for outdoor use whereas the rear wheel drive powered patient transport vehicle  5  is generally more suitable for indoor use. 
       FIGS. 12-14  are various views of a third embodiment of a powered patient transport vehicle  5 B incorporating an improved motion control  10 B of the present invention. The powered patient transport vehicle  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 powered patient transport vehicle  5 B for controlling the powered patient transport vehicle  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 powered patient transport vehicle  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 powered patient transport vehicle  5 B. 
       FIG. 16  is a side view similar to  FIG. 12  illustrating an occupant  70 B seated in the powered patient transport vehicle  5 B with the occupant  70 B controlling the powered patient transport vehicle  5 B. 
       FIG. 17  is a top view of the powered patient transport vehicle  5 B of  FIGS. 12-16  illustrating neutral force applied to the steering bar  90 B of the powered patient transport vehicle  5 B by the occupant  70 B for directing the powered patient transport vehicle  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 powered patient transport vehicle  5 B by the occupant  70 B for turning the powered patient transport vehicle  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 powered patient transport vehicle  5 B by the occupant  70 B for continued turning the powered patient transport vehicle  5 B. 
     It should be appreciated by those skilled in the art that a powered patient transport vehicle may be fashioned to provide the attendant controlled powered patient transport vehicle  5  as shown in  FIGS. 1-11  as well as the occupant controlled powered patient transport vehicle  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.