Abstract:
Disclosed is a vehicle driver wheelchair lift, the lift having a bearing mount fixed to the vehicle that rotationally captures a pivot rod to which a pair of forks are attached by a parallelogram linkage. The rod rotates in the bearing to move the forks horizontally in and out of the vehicle, while the parallelogram linkage expands and contracts to raise and lower the forks. The purpose of the parallel linkage is to allow the forks to move vertically while maintaining a horizontal position. The forks are adapted to engage a pair of horizontal fork receivers fixed to a wheelchair. A vertical linear actuator expands and contracts the linkage to raise and lower the forks vertically. A motor turns the pivot rod to rotate the forks horizontally. In one exemplary embodiment, a lock on the forks secures the receivers and chair on the forks and a sensor signals when the receivers are in locked position suitable for raising and lowering. In one exemplary embodiment, the parallel linkage has outwardly offset lower joints to establish a preset raised position at maximum extension.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is a continuation-in-part of and claims the benefit of U.S. patent application 11/849,283, filed on Sep. 1, 2007 and U.S. Provisional Patent Application 60/841,637, filed on Sep. 1, 2006. 
     
    
     FEDERALLY SPONSORED RESEARCH 
       [0002]    Not Applicable. 
       BACKGROUND OF THE INVENTION 
       [0003]    This invention relates to the field of self-loading or unloading vehicles and more specifically to loading and unloading wheelchairs from vehicles such as classified in class  414 , subclass  540 . 
         [0004]    Persons confined to wheelchairs have limited options pertaining to driving vehicles. Typically, vehicles that are available to disabled persons are necessarily large vehicles, such as vans, which provide internal room sufficient to contain prior art wheelchair lift or ramp devices. Ramp-type devices require the most room inside a vehicle, since a pathway from the ramp—typically on the side of the vehicle—to the driver&#39;s seat area of the vehicle must be kept clear. 
         [0005]    Some lift devices require a dedicated chair fixed to a lift mechanism of the vehicle. A wheelchair-bound driver of such a vehicle must transfer from his wheelchair to the chair of the vehicle. Likewise, when exiting the vehicle, the driver must transfer back to his wheelchair. Aside from the obvious drawback of having to transfer between chairs, which is time consuming, the driver must also be able to readily store his wheelchair somewhere in the vehicle and must do this after having transferred into the dedicated chair. Normally this means a passenger is required to handle the wheelchair, and that obviously limits the freedom of the driver to drive when and where he wants. 
         [0006]    Some other lift devices require specific types of wheelchairs having retractable wheels. To use such a device, the driver must use the wheelchair that comes with these lift devices. But such wheelchairs are cumbersome for normal use since they have extra wheel retracting mechanisms and are not as easy to use outside of the vehicle as conventional wheelchairs. 
         [0007]    Some other lift devices require a wheelchair fitted with a lift plate that cooperates with a lift arm of the devices. Engaging the wheelchair with the device can be difficult. Further, such a device provides no means for moving the wheelchair towards the steering wheel of the vehicle when inside the vehicle. As such, if the occupant wishes to be closer to steering wheel or pedals of the vehicle, the user must disengage from the lift arm. Yet disengaging from the lift arm reduces the safety of the device in use, since the wheelchair is then no longer kept in place by the lifting mechanism. 
         [0008]    Therefore, there is a need to provide further options for wheelchair confined people such as a better wheelchair lifting device that reduces at least some of the above problems. 
       SUMMARY 
       [0009]    In a first exemplary embodiment, a bearing is fixed to the vehicle and a pivot arm has a first end rotationally captured within the bearing and free to rotate therein. The pivot arm also has an outer end configured with a fork and a parallelogram linkage to allow vertical movement of the fork while maintaining the fork in a horizontal orientation. The fork on a wheelchair first exemplary embodiment also has a first linear actuator to horizontally rotate the pivot arm to move the wheelchair horizontally in and out of the vehicle, and a second linear actuator to raise and lower the fork to lift the wheelchair into an elevated position high enough that it can be rotated horizontally into the vehicle. The first exemplary embodiment also contains a sensor on the fork since when the wheelchair is in a fully engaged position on the fork and to prevent lifting, rotating and lowering except when the wheelchair is such fully engaged position. The parallelogram lifting mechanism includes a front and rear mounting plate connected to each other by parallel arms. The front mounting plate is connected to the fork and maintains the fork in a horizontal position during vertical lifting, while the rear mounting plate is connected to the pivot arm to maintain that position during rotation. This results in a very secure, compact, and reliable system. 
         [0010]    The first exemplary embodiment allows the wheelchair to be easily engaged to the lift device with minimal modification thereto. The first exemplary embodiment will not operate unless the wheelchair is in a proper position on the lifting mechanism. The present invention uses little room within the vehicle and can be used with relatively small vehicles. Further, the present device serves to keep the wheelchair locked into place laterally and vertically within the vehicle when the device is in an inside-vehicle position. In short, the first exemplary embodiment is a better wheelchair lifting device that reduces at least some of the problems described in the background portion of this application. Other features and advantages of the present invention will become apparent from the following more detailed description, taken in conjunction with the accompanying drawings, which illustrate, by way of example, the principles of the invention. 
     
    
     
       DRAWINGS 
         [0011]      FIG. 1  is a partial perspective exploded view of a first exemplary preferred embodiment of the invention; 
           [0012]      FIG. 2  is a partial top plan view of the first exemplary embodiment, illustrating the first exemplary embodiment in an inside position; 
           [0013]      FIG. 3  is a partial top plan view of the first exemplary embodiment, illustrating the first exemplary embodiment in an outside position; 
           [0014]      FIG. 4  is a left side elevational view of the first exemplary embodiment in a lower position; 
           [0015]      FIG. 5  is a partial left-side elevational view of the first exemplary embodiment in a raised position; 
           [0016]      FIG. 6  is a left-side elevational view of the first exemplary embodiment, illustrated in an outside position an not engaged with a wheelchair; and 
           [0017]      FIG. 7  is a left-side elevational view of the first exemplary embodiment, illustrated in the raised and inside position, and engaged with the wheelchair. 
       
    
    
     DETAILED DESCRIPTION 
     Exemplary Best Mode (Preferred Exemplary Embodiment) 
       [0018]    The seven  FIGS. 1-7  illustrate a first exemplary embodiment of a system  10  for lifting an driver  28  in a wheelchair  20  into and out of a vehicle  30 .  FIG. 1  shows system  10  without wheelchair  20  or vehicle  30 , while  FIG. 5  shows wheelchair  20  in place and system  10  in a first inside position  130  where driver  28  is properly located and oriented to drive vehicle  30 . Vehicle  30  is a Dodge, Chevy, or Ford “Quad-Cab” truck, but could be any other vehicle having a sufficiently large side opening.  FIG. 3  shows vehicle  30  has a sturdy frame  35  typically including a bar  201 , a bar  202  and a bar  203  and other bars (not shown). Vehicle  30  has so-called “suicide-swing” rear door  502  that have a rear hinge (not shown) to open from the front and thus away from a forward door  506 , providing a wider opening  510  for wheelchair  20  to enter vehicle  30 . For safety purposes, a sensor  200  and a sensor  202  are provided to sense when wheelchair  20  is safely in a position fully engaged with a lock  113  and a lock  114 , respectively, on lift fork  100  and lift fork  101  of system  10 , in a manner described below. 
         [0019]    A bearing mount  40  is fixed to a sturdy bar  201  of frame  35  of vehicle  30  and includes a bearing mounting means  44 , an inward extension  160  and a vehicle mounting means  46  ( FIG. 4 ). Bearing mounting means  44  is preferably an aperture  45  within bearing mount  40  that is adapted to securely receive a bearing means  50 . A pivot rod  60  has an upper portion  66  and a lower end  64 , lower end  64  being rotationally captured within bearing means  50 . Bearing means  50  comprises an upper ball bearing housing  55  containing a first set of ball bearings  56  and a first inner ring  57  and a matching opposed lower ball bearing housing  54  that rotationally captures a second set of ball bearings  58  and a second inner ring  57 . Second inner ring  57  frictionally receives lower end  64  of pivot rod  60 . As such, pivot rod  60  is free to rotate horizontally within bearing means  50 , but maintains a constant height  500  above a bottom  501  of door opening  700 . Both bearing mount  40  and pivot rod  60  are preferably strong rigid metal or strong rigid composite material so as to be able to support the weight of driver  28 , wheelchair  20  and system  10  and still easily pivot in a horizontal direction. 
         [0020]    Vehicle mounting means  46  is preferably at least two apertures  47  in bearing mount  40  through each of which a bolt  48  may be used to fasten bearing mount  40  to vehicle  30 . Other vehicle mounting means  46  may be used as desired, however, such as welding mount  40  to vehicle  30 . Preferably bearing mount  40  is fixed to a frame  35  of vehicle  30  at a portion thereof proximate to a driver&#39;s side rear door  502 , but can also be mounted proximate a passenger side door. 
         [0021]    A rigid rear mounting plate  70  is fixed to an upper portion  66  of pivot rod  60  and includes four arm mounting means  75  that are pivotally mounted, one to a rear end  82  of parallel arm  78 , one to a rear end  83  of parallel arm  79 , one to a rear end  84  of parallel arm  80  and one to a rear end  85  of parallel arm  81 . Such arm mounting means  75  are horizontal bolts, although pins, bearings or other fasteners that allows the desired vertical rotation could be substituted. In order to achieve maximum extension of arm  80  and parallel arm  81  in a preferred raised position  112  as seen in  FIG. 5 , rear end  85  is located forward of rear end  84  by a distance  401  of three inches. This is depicted in  FIG. 4 . To accomplish this, aright lower extension bar  150  and a left lower extension bar  402  are attached to and extend horizontally forward from a lower portion  151  of rear mounting plate  70  and rear end  85  is attached to a front end  403  of extension bar  402 . In order to maintain a parallelogram  409 , arm  80  and parallel arm  81  need to be of equal length. Accordingly, an extension bar  404  is attached to a lower portion  410  of front mounting plate  90  and projects forwardly from front mounting plate  90  by 3″. A forward end  86  of parallel arm  81  is attached by an arm mounting means  75  to a front end  407  of extension bar  404 . Forward end  86  of parallel arm  81  is pivotally mounted to an upper portion  155  of substantially vertical front mounting plate  90 , such that parallel arm  80  on the top, parallel arm  81  on the bottom, rear mounting plate  70  and extension bar  402  on the rear and front mounting plate  90  and extension bar  404  on the front form four sides of a left side parallelogram  409 . Parallelogram  409  assures that front mounting plate  90  remains vertical and parallel to vertical rear mounting plate  70 . A similar right side parallelogram  170  is also provided. As such, front mounting plate  90  can be raised or lowered with respect to rear mounting plate  70 , arms  80  and parallel arm  81  each pivoting vertically and in parallel with respect to rear mounting plate  70  to maintain front mounting plate  90  vertical and thus maintaining fork  100  and fork  101  horizontal. When left fork receiver  25  and a right fork receiver  26  (not shown) are engaged, respectively by fork  100  and fork  101 , wheelchair  20  is maintained in a stable and constant upright orientation. Plate  90 , bar  402 , bar  404 , left fork receiver  25 , right fork receiver  26 , arm  80  and parallel arm  81  are each made from a rigid metal stock or carbon-fiber material, and are each strong enough and attached rigidly enough to support the weight of wheelchair  20  and occupant  28  without bending, buckling or otherwise distorting. This results in a very stable ift mechanism in which a handicapped person can feel comfortable and secure. 
         [0022]    A rigid metal or carbon-fiber left fork  100  and rigid metal or carbon-fiber right fork  101  are mounted to, and project horizontally forward from front mounting plate  90  and are adapted to engage, respectively horizontal left fork receiver  25  and horizontal right fork receiver  26  that are fixed to wheelchair  20  ( FIG. 4  and  FIG. 5 ) to adapt wheelchair  20  for use with system  10 . This is a simple fixed conversion for a wheelchair, as left fork receiver  25  and right fork receiver  26  can be simply located beneath the armrest of wheelchair  20  in a relatively inconspicuous manner out of the way of wheelchair  20  during normal use and do not interfere with folding of wheelchair  20 . Left fork receiver  25  and right fork receiver  26  are lightweight metal or carbon-fiber tubes that are fixed to wheelchair  20  with any suitable mounting means such as with bolts, welding, or the like (not shown). Left fork receiver  25  and right fork receiver  26  are laterally spaced the same distance apart as fork  100  and fork  101 . Fork  100  and fork  101 , moreover, may be adjusted on front mounting plate  90 , such as by bolting fork  100  to front mounting plate  90  at a desired location. A pin  113  fixed to fork  100  serves to retain left fork receiver  25  onto fork  100  when fork  100  is in a raised position  112  ( FIG. 5 ). A rear end  700  of left fork receiver  25  and right fork receiver  26  are flared to make left fork receiver  25  and right fork receiver  26  self-correct for slight misalignment when being aligned with fork  100  and fork  101 . Fork receiver  25  and right fork receiver  26  pass easily over pin  113  and pin  114 , respectively, when fork  100  and fork  101  are lowered. However, pin  113  and pin  114  lock receiver  25  and receiver  26  on fork  100  and fork  101  when fork  100  and fork  101  are raised. 
         [0023]    One left vertical linear actuator  109  and one right vertical linear actuator  110  are fixed between rear mounting plate  70  and front mounting plate  90  and are adapted to selectively raise and lower front mounting plate  90 , fork  101 , and fork  100  with respect to rear mounting plate  70  and vehicle  30 . Linear actuator  109  and linear actuator  110  are motor-driven screw drives  115  and linear actuator  120  motor-driven is a motor-driven screw drive  125  as illustrated in  FIG. 1  and  FIG. 2 . An actuator control  118  is adapted to activate linear actuator  110  and is mounted to front mounting plate  90  and is in electrical series with sensor  200  and/or sensor  202 , such that an occupant  28  of wheelchair  20  may activate actuator control  118  only when wheelchair  20  is fully seated on fork  100  and fork  101 . 
         [0024]    In use, rear mounting plate  70 , front mounting plate  90 , arm  78 , arm  79 , arm  80 , parallel arm  81 , fork  100  and fork  101  rotate together horizontally from an inside position  130  inside vehicle  30  to a substantially outside position  140  outside of vehicle  30  about the pivot rod  60 . When moving into the inside position  130 , linear actuator  110  is in raised position  112 . Once inside position  130  is achieved, linear actuator  110  may be lowered slightly as desired by occupant  28 , such that front wheels  711  and rear wheels  712  of wheelchair  20  contact floor  702 , locking wheelchair  20  in place laterally and vertically in a driving position yet allowing forward movement of wheelchair  20  further under steering wheel  708 . When rear mounting plate  70 , front mounting plate  90 , parallel arm  78 , parallel arm  79 , arm  80 , parallel arm  81 , fork  100  and fork  101  are rotated into outside position  140 , linear actuator  110  may be contracted to move fork  100  and fork  101  from raised position  112  to a lower position  111 . 
         [0025]    Preferably, at least one horizontal linear actuator  120  is fixed between vehicle  30  and rear mounting plate  70 . Horizontal linear actuator  120  has a motorized screw-drive  125  adapted to selectively rotate front mounting plate  90 , arms  80  , fork  100  and fork  101  between inside position  130  and outside position  140 ,  140  ( FIG. 2  and  FIG. 3 ). A second actuator control  128  is adapted to activate horizontal linear actuator  120 , and is mounted to actuator control support bar  405  attached atop and extending forwardly from front mounting plate  90  near actuator control  118 . As such, occupant  28  may reach both actuator control  118  and actuator control  128  when wheelchair  20  is fully engaged to fork  100  and fork  101 , or by remote control when outside of vehicle  30  and not engaged to fork  100  and fork  101 . 
       Operation of the Exemplary Best Mode 
       [0026]    When a solitary wheelchair-confined user  601  approaches vehicle  30 , user  601  can use remote control  600  to remotely open front door  506  and remotely activate motor  503  open rear door  502 , thus exposing system  10 . Next, operator  601  can remotely extend actuator  120  to cause pivot rod  60  rotate to move fork  100  and fork  101  from inside position  130  to outside position  140  and then remotely activate vertical actuator to lower fork  100  and fork  101  from raised position  112  to lower position  111 . User  601  then aligns and backs wheelchair  20  and receiver  25  and receiver  26  onto fork  101  and  100 , respectively, with flared end  602  assisting in such alignment. Sensor  200  and sensor  202  sense that wheelchair  20  is in place. User  601  then uses actuator control  118  or  618  to raise fork  100  and fork  101  and wheelchair  20  into position  112 . When sensor  507  senses contact of front plate  90  sensor  507  enables operation of control  128  and disables control  118  (to prevent lowering during inward rotation). User  601  then activates control  128  to rotate rod  60  clockwise to move fork  100  and fork  101  and wheelchair  20  from outer position  140  to inner position  120  to move wheelchair  20  horizontally into vehicle  30  through opening height  510 . For a quad cab pickup truck, user  601  will normally need to duck his head to get under top  505 . Completion of movement into the vehicle is sensed by contact of rear plate  70  with sensor  204 , which then disables control  128  and enables control  118  so that wheelchair  20  can be lowered onto the floor of vehicle  30  as required by law. Wheelchair  20  can then be moved forward further under steering wheel  708  to a desired final driving position. A floor lock  707 , such as Model BL-7317 provided by EZ-Lock can be added to securely hold wheelchair in the desired final driving position. This completes the movement from ground to vehicle in an independent manner so that solitary wheelchair-confined user  601  can employ system  10  to achieve use of a pickup truck without assistance. Likewise, control  600  would also allow system  10  to reverse such movements to return system  10  to move from truck to ground. When rear mounting plate  70 , front mounting plate  90 , parallel arm  78 , parallel arm  79 , arm  80 , parallel arm  81  and forks  100  are rotated into outside position  140 , linear actuator  110  may be extended to move fork  100  and fork  101  from raised position  112  to a lower position  111 . Also, once on the ground, control  600  can be used to move system  10  back to inside position  130  after wheelchair  20  exits system  10 , thus permitting vehicle  30  and system  10  to be locked and secured from theft or tampering, again by a solitary wheelchair-confined user  601  without assistance. When user  601  desires to again drive the truck, the process is repeated. The sense of freedom and empowerment provided to a wheelchair-confined user  601  in this age of dependence on vehicles for transportation is substantial and of significant benefit to society. This is especially true when so many victims of IED explosions from the Iraq and Afghanistan wars have severe leg injuries necessitating confinement to wheelchairs. And, this system  10  enables use of a pickup truck so user  610  feels much more normal since user  610  does not have to have a typical large modified van. In modern pickup trucks, the door opening height  512  and width (length)  509  are limited by the height and length of the cab. So, a quad cab pickup will be the vehicle of choice so that instead of a standard door opening width  508 , a much greater width  509  can be provided. Referring to  FIG. 7 , for example, the cab of vehicle  30  has a ceiling  706  located at a height  703  of 54″ above a specially sunken floor  702  and a door opening  510  of 49″ height from a bottom  704  to a top  705  and bottom  704  is located a certain distance  511  above the ground. When sitting in wheelchair  20 , the height  709  of the top of the inventor&#39;s head is a distance  710  of 51″ above the bottom of the wheels, a special sunken floor  702  was used to get a couple of additional inches in floor to ceiling height  703  to make height  703  greater than height  710 . Since wheelchair  20  needs to be precisely positioned in order to fit through opening  510  to allow use of such a pickup truck as vehicle  30 , tall occupants  28  will need to duck their head to fit in when lifted even just a couple of inches above floor  702  to make height of their head to less than 47″ (49″ less the couple of inches above the floor”. To achieve maximum extension of arm  80  and parallel arm  81  at a precise preferred raised position  112  as seen in  FIG. 5 , rear end  85  is located forward of rear end  84  by a distance  401  of three inches. This is depicted in  FIG. 4 . To accomplish this, right lower extension bar  150  and a left lower extension bar  402  are attached to and extends horizontally forward from a lower portion  151  of rear mounting plate  70  and rear end  85  is attached to a front end  403  of extension bar  402 . In order to maintain a parallelogram  409 , arm  80  and parallel arm  81  need to be of equal length. Accordingly, an extension bar  404  is attached to a lower portion  410  of front mounting plate  90  and projects forwardly from front mounting plate  90  by a distance equal to distance  401 . When moving wheelchair  20  into the inside position  130 , linear actuator  110  is in raised position  112 . Once inside position  130  is achieved, linear actuator  110  may be lowered slightly as desired by occupant  28 , such that wheelchair  20  wheels contact floor of vehicle  30  as legally required and enabling locking wheelchair  20  in place in a driving position by use of a wheelchair docking system such as an EZ-LOCK Model BL-7317 sold by EZ Lock Inc. of 2001 Wooddale Blvd., Baton Rouge, La. 70806. 
       Alternative Embodiments 
       [0027]    While a particular preferred exemplary embodiment of the invention has been illustrated and described, it will be apparent to skilled artisans that various modifications can be made without departing from the spirit and scope of the invention. For example, distance  401  is 3″ in the best mode, but can be within a range of 2″-4″, more preferably within a range of 2.5″ to ⅗″ and even more preferably within a range of  2 . 8 ″ to  3 . 2 ″, with the precise dimension chosen to achieve the precise height for clearance With suitable modification of a car, system  10  could be adapted to enable user  610  to use a car without assistance. For example the rear driver side passenger door would be switched to open rearward rather than forward and the normal sidepost might be made integral with the rear door so the full driver side could be accessed in similar fashion to the rear opening rear door on vehicle  30 . Modification of distance  401  would be coupled with suitable modifications of other dimensions of the parallel linkage. As another alternative, a single vertical linear actuator  110  might be used rather than a pair as in system  10  although a pair would minimize stress on the system and prolong life. By way of further example, a single or pair of vertical screw-drive mechanisms might be used instead of the parallelogram linkage to achieve pure vertical movement of fork  100  and fork  101 . A second horizontal screw-drive mechanism might be used to shorten or lengthen the pivot arm. That would have the advantage of (a) allowing forward movement of wheelchair  20  once in the vehicle  30  to put the driver closer to the steering wheel and other driver control devices, (b) allowing rearward movement of wheelchair  20  out from under the steering wheel prior to being rotated out of the vehicle  30  is easy and (c) maintaining the wheelchair  20  engaged with the lifting mechanism in all three directions (vertical, lateral and fore and aft). As another example, pin  113  might be replaced by a powered pin that could be lowered out of the way until wheelchair  20  was fully on fork  100  and fork  101  as determined by sensors  200  and  202  and then lifted up to securely lock wheelchair  20  onto fork  100  and fork  101 . Various other locking mechanisms might also be substituted. Likewise, various other sensors might be used instead of sensor  200  and sensor  202 . For example pin  113  and/or pin  114  might open (i.e. turn off) the power circuit to control  118 ,  128 ,  618  and  628  when pin  113  and/or pin  114  is depressed. That would prevent operation of system  10  while left fork receiver  25  and right fork receiver  26  (not shown)were over pin  113  and/or pin  114 , so that system  10  could not be operated while the wheelchair  20  was in the process of being backed onto fork  100  and fork  101  until such time as left fork receiver  25  and  26  had cleared pin  113  and/or pin  114  and pin  113  and/or pin  114  had raised to block left fork receiver  25  and right fork receiver  26  from coming forwardly off of fork  100  and  101 . A suitable release button (not shown) would then be added to release pin  113  and pin  114  for depression to allow left fork receiver  25  and right fork receiver  26  to move forwardly off of fork  100  and fork  101  after lowering. Remote control  600  could then be activated to return system  10  to raised position  112  and then to inside position  130  in vehicle  30  so that vehicle  30  could be locked. While I have found that many injured soldiers might prefer a big “bad-ass” ride like the Quad Cabs noted above, others might be more concerned with fuel economy and want something smaller. Accordingly, other vehicles may be modified to accommodate the system  10  such as, for example, a smaller truck, SUV or crossover or minivan modified by removing the driver seat and making the driver door opening sufficiently large to accommodate a system  10  and wheelchair  20 , perhaps with a lowered seat adapted lower or incline the driver sufficiently to fit such vehicle. As a further example, tube-like left fork receiver  25  might be replaced by simple right angle bars or U-bars welded to a frame of wheelchair  20 . Also, various types of linear actuator  110 ,  120  may be used as suitable for the present application. Likewise, pin  113  and pin  114  can be spring-biased and retractable to make passage of fork  25  and right fork receiver  26  over pin  113  and pin  114  even easier. Alternately, however, either linear actuator  110  or linear actuator  120  may be a fluidic cylinder (not shown), either hydraulic or pneumatic depending on the available systems of vehicle  30  or any additional pumps and motors. 
       Conclusion and Scope 
       [0028]    In conclusion, the reader will see that I have provided a better wheelchair lifting device that makes pickup trucks and the like accessible for wheelchair-confined individuals, and does so in a manner that enables unassisted use. This is a significant benefit to the increasing number of such individuals. 
         [0029]    While the above description contains many specificities, these should not be construed as limitations on the scope of the invention, but as exemplifications of the presently preferred embodiments thereof. Accordingly, the exemplary best mode shown is just that, exemplary in order to meet best mode and enablement requirements, and not intended to limit the scope of the invention. For limitations, reference should be had to the following claims which are intentionally broader than the exemplary best mode embodiment or any exemplary alternate embodiment described above and to the legal equivalents of the claims below.