Abstract:
An improved wheelchair lift-transfer device provides capabilities for a patient or caregiver to independently control the wheelchair and lift functions to elevate and move about safely. The patient can use a handheld wireless remote control and summon their wheelchair lift-transfer device from across the room, to their bedside, then independently transfer into the device and then drive it about in their home, raising and lowering their body as needed.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation in part of PCT Application number PCT/US2011/041320, filed Jun. 22, 2011, which PCT application claims priority from provisional application Nos. 61/398,174, filed on Jun. 22, 2010 and 61/462,042, filed Jan. 27, 2011, and all of which are incorporated herein by reference. 
    
    
     FIELD OF THE INVENTION 
     This invention relates to an improved patient transfer-lift and rotation device that can be used as a patient controlled wheelchair. Another embodiment is especially suitable for patient transfers within passenger aircraft. 
     BACKGROUND OF THE INVENTION 
     In a first aspect of the invention, many patients desire mobility and independence. Conventional patient controlled powered wheelchairs are front entry in that the supporting structure is under and behind the seated user, and even though they provide great mobility, the conventional wheelchair is hampered by front entry when lifting and transfer capabilities are added. Conversely, wheeled patient transfer-lifts are usually rear entry in that the patient faces and is suspended from the lifting structure. Also, transfer-lifts are nearly exclusively operated by a caregiver even though the patient being lifted and transported may have significant capabilities. Rear entry transfer-lifts offer an advantage in transfer operations by the natural orientation of the patient that compliments transfer to other equipment or furnishings. It is easier to place a patient into a front entry conventional wheelchair or place a patient on a bed or toilet from a rear entry transfer-lift device. Wheeled transfer-lifts have rear wheel support arms that can be widened to improve stability when the lift is elevated. 
     There are numerous patient lift devices that have adequate lifting capability for certain situations; however those with lifting range sufficient to lift a patient from lying on the floor to standing height are not both compact and mobile. There are ceiling mounted lifts with great lifting range but these are confined to a ceiling track or large frame structure. There are boom arm lifts with fairly high lifting range but to increase lifting range these lifts have long boom arms and long support structures to achieve the greater lift range. There are jackscrew driven and hydraulic driven vertically guided lifts that have high lift ranges but these lifts have very tall guide support structures that increase their height and reduce their mobility. 
     Wheeled lifts are often used to aide in transferring to a conventional wheelchair and therefore have support structures that straddle the wheelchair during this transfer operation. Moving to and from the wheelchair, such wheeled lifts must often pass through common width doorways so the width of the support structure must have a means to be reduced. Therefore, most wheeled lifts have provisions to move some portion of the support structure from wide to narrow width as needed. Many wheeled lifts have outwardly pivoting wheel support arms that can be swung outward to widen the structure for transfers to and from a wheelchair. The required wide angle of the wheel support arms results in a width between the ends of the pair of extended arms that is much wider than the wheelchair. A few lift types have sidewardly sliding sections that provides a wider opening for straddling a wheelchair. 
     Commonly, wheeled lifts have a single central column at one end from which the boom arm extends or the lifting section telescopes. This structure simplifies the lift mechanism but the structure resulting from this central location interferes with the patient&#39;s knees and also makes it difficult to locate the lifting point of the lift close enough to a patient that is lying on the floor. 
     U.S. Pat. No. 6,430,761 describes a Compact Portable Patient Lift that is intended to be portable but it has inadequate lifting range to lift a patient from lying on the floor to standing, it has an interfering central lifting support column and does not provide the capability for self-lifting or patient driving. U.S. Pat. No. 4,719,655 describes a patient lift with two telescoping vertical guide columns but also has an interfering central lift mechanism and no means to adjust the width of the wheel support arms. U.S. Pat. No. 6,161,232 describes an Invalid Lifting Device having two vertical lifting columns, each having front and rear wheels wherein the columns can be adjusted to the desired width from the other. However, this device has very tall columns to achieve the high lift range and has no provision for patient operation of the lift. U.S. Pat. No. 5,466,111 describes a method wherein the seat lift of a wheelchair is used to raise a wheelchair and patient occupant into a vehicle by attaching the upper portion of the wheelchair to the vehicle door and then swinging the door shut to move the wheelchair and occupant into the vehicle. However, this method requires a vertically hinged door to carry the raised wheelchair and most vehicle floors are too high for the illustrated seat lift to achieve an adequate height to clear the vehicle floor to allow entry and this method will not work when the vehicle door has a horizontal hinge axis like a van rear door. 
     U.S. Pat. No. 6,092,247 for a Powered Patient Lift Vehicle, describes an earlier attempt by the present inventor to provide a patient operated lift that could also be driven as a wheelchair. However, this device achieves some of the capabilities of the present invention, but it has the long boom arm affect, the outwardly swinging wheel arm supports, and is too large for easy portability in a vehicle. It also does not assist in raising the device itself to higher levels. U.S. Pat. No. 5,255,934 is another earlier attempt by the present inventor to provide a power driven wheelchair with a lifting capability. However, this is a front entry wheelchair with the lift motor, battery and cross shaft below the patient which eliminates the ability to move over a patient lying on the floor. There is no provision to move the rear wheel support arms outward to improve stability when elevated. Also, this device has only a single jack screw in each lift column and the lift column height increases directly proportional to the lift stroke which makes the higher lift version too tall when retracted. There is no provision or lift range for using the lift mechanism for self lifting the entire unit from one level to a higher level. 
     There is a need for a patient-operated rear entry lifting, rotation, transfer and transporting device that can also serve as a wheelchair that is compact enough to fit inside a vehicle and easily transported for use at another location. 
     The ideal wheelchair lift-transfer device of the invention provides capabilities for a patient to independently control the wheelchair and lift functions to elevate and move about safely so that he or she can communicate eye to eye with others and retrieve items that are normally too high to reach. Such independence would be demonstrated by the patient when they grasp a handheld wireless remote control and summon their wheelchair lift-transfer device from across the room, to their bedside, then independently transfer into the device and then drive it about in their home, raising and lowering their body as needed. Later they can drive to their bed, lower their self onto the bed, release from the lift and then with the handheld wireless remote control, drive the wheelchair lift-transfer device clear of their sleeping area. For certain performance requirements, the patient may need to transfer to their conventional power drive wheelchair. The independent patient can drive the wheelchair lift-transfer device over to their conventional wheelchair, adjust the rear wheel support arm width as needed, reverse the direction of the wheelchair lift-transfer device and lower themselves onto their conventional wheelchair and then complete the transfer by driving the wheelchair lift-transfer device away from the user, now in the conventional wheelchair, into a parking position by use of the handheld wireless remote control. 
     When a caregiver is present and can assist in the operation, this ideal wheelchair lift-transfer device of the invention will provide even more capabilities such as by raising the patient off of the floor and placing them in a seated position on a chair or bed or, standing them up on the floor. In this case, the wheelchair lift-transfer device of the invention will also be configured to utilize the integral lifting capability to not only lift the patient but also to lift a conventional wheelchair or other equipment into a vehicle and subsequently lift the wheelchair lift-transfer device its self into a vehicle or lift it from a lower level floor, upward, for use on a higher level floor or platform. The inventive wheelchair lift-transfer device includes integral sensors and control logic that will minimize unsafe use. 
     In a second aspect of the invention, frequently patients must be transferred from their conventional wheelchair, transported through narrow isle ways and then transferred to a stationary seat, such as an aircraft passenger seat. When a patient&#39;s conventional wheelchair will be transported as aircraft baggage a patient may be transferred to a conventional push chair at the gate and then transferred again to an “Isle Chair” just inside the aircraft cabin. An isle chair is narrow and a supported patient is moved down the aisle to their seat location where they must be lifted from the aisle chair into a passenger seat. This procedure can cause injury to both a patient and attendants. 
     U.S. Pat. Nos. 4,639,012, 4,639,012 and 6,929,275 are examples of Aisle Chairs. They are basically narrow chairs that fit the narrow aircraft aisle ways with no features provided for elevating the patient to aide in transfer from a conventional wheelchair or to an aircraft seat. U.S. Patent Application Publication US 2010/0251481 discloses a lifting device apparently intended to accomplish many of the same objectives of this invention; however the device, having an overhead lifting frame, is too large and too tall for practical use and storage within the aircraft. U.S. Patent Application Publication US 2009/0144895 discloses a lifting device having overhead patient lifting and rotation features that is also too large and too tall for practical use within an aircraft. 
     There is a need for an improved wheeled patient lift-transfer device that will lift a patient from a conventional wheelchair, transport him or her through narrow passage ways, rotate him or her to face in a desired direction and lower him or her on to a stationary seat that may be confined on all sides by other seats or structures. The lift-transfer device can be propelled by the attendants or could be provided with electric motor drives for both transport and lifting energy. 
     Therefore, the objects of the present invention are to provide: 
     1. A compact patient lift-transfer device with increased lifting range, including lifting a patient from lying on the floor to standing position yet have a retracted column height that will pass under a normal height table top. 
     2. A compact wheelchair lift-transfer device that improves transfer to and from conventional wheelchairs by providing a pair of independently adjustable rear wheel support arms that remain substantially parallel when they are adjusted, including a range of adjustment that allows a narrow position for passage of the pair of support arms under and between the wheels of a conventional wheelchair and a wide position that allows space for a chair to sit between the wheel support arms and/or provide improved stability for driving the wheelchair lift-transfer device with the lift elevated. 
     3. A compact rear entry wheelchair lift-transfer device that improves transfer to and from a bed including a semi-rigid seat plate that can be easily placed under a patient who is on a bed and be quickly attached to the lift. 
     4. A compact patient controlled power drive wheelchair lift-transfer device that can serve as a rear entry lift transfer that can carry the patient around the house, place them on a toilet, sit them close up to a table or lift them up to reach high objects such as in a kitchen cupboard. 
     5. A compact patient wheelchair lift-transfer device that provides patient independence by providing a battery powered wheelchair lift-transfer device that can be remotely controlled by the patient to bring the device to the patient who is in a bed or in a conventional wheelchair and then allow the patient to control the lift to cause it to lift the patient from the bed or wheelchair and then drive the lift transfer device to another location with patient carried along and under control of the patient. 
     6. A compact patient wheelchair lift-transfer device that is easily transportable and self lifting for transfer into a vehicle that can be used to lift and transfer a patient from a conventional wheelchair into a vehicle seat, then be used to lift the conventional wheelchair into the vehicle and finally provide a self lifting means to lift the wheelchair lift-transfer device into the vehicle to be taken along to lift all the above out of the vehicle again, later. 
     7. An optional compact patient wheelchair lift-transfer device having a U-shaped patient lifting frame that includes rotation, lifting and driving means. 
     8. A compact lift-transfer device that improves transfer to and from conventional wheelchairs by providing a U-shaped rotatable lift frame that positions and supports the patient substantially within the U-shaped frame thereby keeping the patient&#39;s center of gravity within the U-shape (as viewed from above), the patients backside facing outward through the open side of the U-shape and the height of the lift structure reduced. 
     9. A U-shaped lifting frame that forms a rotation track that is supported on a series of rollers or bearing surfaces that allows the U-shaped frame to be rotated as the track moves through the series of supporting rollers, thereby rotating the lifting frame and patient about a vertical axis. 
     10. An optional compact lift-transfer device having a wheeled base with at least 3 supporting wheel locations whereby the frame of the base can be adjusted so at least one wheel is moved to a position closer to the other wheels so that the base width becomes substantially narrowed to allow the lift-transfer device to pass through a narrow passage way. 
     11. An optional compact patient lift-transfer device wherein the patient U-shaped lifting frame may be moved to position the patient over the wheeled base into the most favorable position for stability of the patient and transfer device when considering the width of the wheeled base. 
     12. An optional compact patent lift-transfer device having at least one offset substantially vertical lifting column, the upper end of which a U-Shaped lifting frame is cantileveringly attached so that the U-shape of the lifting frame is oriented substantially horizontal and located generally above the wheeled base. 
     13. An optional compact patient lift-transfer device wherein the wheeled base has at least one wheel support arm that is pivotally mounted to allow base width adjustment. 
     14. An optional compact lift-transfer device wherein the patient can be rotated 90 degrees about a vertical axis when the base wheel locations have been adjusted to provide increased stability. 
     15. An optional compact lift-transfer device that can be assembled to serve as either a Right Hand or Left Hand device, that being a Right Hand Device when the patient is transferred into a seat on the right side of an isle way as the patient faces forward or Left hand device when the patient is placed on the left side of the isle way when facing forward. 
     Other objects and purposes of the invention, and variations thereof, will be apparent upon reading the following specification and inspecting the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of one embodiment of the patient wheelchair lift-transfer device configured as a rear entry power drive wheelchair. 
         FIG. 2  is a fragmentary perspective view of the power drive wheelchair embodiment showing a mounted Joy-Stick Control module. 
         FIG. 3  is a fragmentary perspective view of the seat assembly (detached from the Transporter and moved lower and rearward). 
         FIG. 4  is a fragmentary perspective bottom view of the front portion of the power drive wheelchair embodiment. 
         FIG. 5  is a perspective view of one embodiment of the patient wheelchair lift-transfer device configured as a rear entry wheelchair frame structure without seat, backrest, support straps, or power driving components. 
         FIG. 6  is a fragmentary cut-away perspective view of the upper portion of the LH lift column with hexagon shaft mounted in the spline tube driver. 
         FIG. 7  is a fragmentary cut-away perspective view of the lower portion of the LH lift column showing the inner jack screw secured to the outer column bottom plate. 
         FIG. 8  is a perspective view of the assembled internal double telescoping jack-screw assembly. 
         FIG. 9  is a perspective end view of the spline tube. 
         FIG. 10  is a perspective view of the hexagon-bore spline tube driver. 
         FIG. 11  is a fragmentary perspective view of the spline engaging upper end portion of the outer jack screw. 
         FIG. 12  is a fragmentary perspective view of the lower portions of the telescoping outer and inner jack screw assembly. 
         FIG. 13  is a fragmentary perspective view of the middle tube support assembly 
         FIG. 14  is a fragmentary perspective view showing one of the middle tube support moldings removed to reveal the inner screw nut mounted to the lower end of the outer screw. 
         FIG. 15  is a fragmentary front view of the upper portion of the lift columns and lift gearmotor configuration. 
         FIG. 16  is a fragmentary view of the upper right front showing the projecting powered lift release lever. 
         FIG. 17  is a perspective view of the hexagon-bore cross-shaft to gearmotor power link. 
         FIG. 18  is a perspective view of the powered lift release lever. 
         FIG. 19  is a fragmentary cut-away perspective view of the powered lift lever and power link disengaged from the lift gearmotor for hand crank operation. 
         FIG. 20  is a fragmentary cut-away perspective view of the powered lift lever and power link engaged with the lift gearmotor for power lift operation. 
         FIG. 21  is a fragmentary cut-away perspective view of the upper LH column gear block with hexagon bore crank handle attachment coupler. 
         FIG. 22  is a similar view of this area with gear block removed to reveal the LH configuration of the bevel gears and supporting radial bearings. 
         FIG. 23  is a similar cut-away view of the RH column gear block. 
         FIG. 24  is a similar view with the RH gear block removed to reveal the RH configuration of the bevel gears and supporting radial bearings. 
         FIG. 25  is a fragmentary cut-away perspective view of the hexagon cross shaft, worm gear, moving gear-rack and mounted switches provided for lift-height position sensing (electric wire connections omitted). 
         FIG. 26  is an expanded view of above showing the gear-rack indicating the lift is in a fully retracted position. 
         FIG. 27  is a similar expanded view as above showing the gear-rack indicating the lift is in a fully extended position. 
         FIG. 28  is a fragmentary upwardly facing perspective view showing the LH pivot arm linkage with position sensing switch not contacted, indicating that a rear wheel arm is not in the full-wide width position. 
         FIG. 29  is an expanded view of above showing the rear wheel support arm linkage with the rear wheel support arm retracted to a narrow width position. 
         FIG. 30  is a similar view of above showing the rear wheel support arm linkage with the rear wheel support arm extended to the full-wide width position and the position indicating switch is contacted. 
         FIG. 31  is a perspective view of another embodiment of the patient wheelchair lift-transfer device configured as caregiver propelled on front and rear caster wheels. 
         FIG. 32  is a fragmentary upwardly facing perspective view of another embodiment of the patient wheelchair lift-transfer device showing the LH rear wheel support arm linkage with the rear wheel support arm extended to a wide width position by a hand-crank driven screw-actuator. 
         FIG. 33  is a similar view showing the LH rear wheel support arm linkage with the rear wheel support arm retracted to a narrow width position by a hand-crank driven screw-actuator. 
         FIG. 34  is a perspective view representing a patient lying on the floor; the lift seat board has been placed under the patient. 
         FIG. 35  is a perspective view showing the wheelchair lift-transfer device maneuvered to straddle the patient; the lift belts have been extended and connected to the seat board. 
         FIG. 36  is a perspective view showing the wheelchair lift-transfer device and patient; the patient has been moved to a sitting position and held by back support belt. 
         FIG. 37  is a perspective view showing the wheelchair lift-transfer device lift columns in an extended position, lifting the seated patient off the floor. 
         FIG. 38  is a perspective view showing the lifted patient lowered on to a support chair. 
         FIG. 39  is a perspective view showing the wheelchair lift-transfer device lift columns in a retracted position with the patient support belts adjusted to a shortened length. 
         FIG. 40  is a perspective view showing the wheelchair lift-transfer device lift columns extended with the patient support belts adjusted to shortened length. 
         FIG. 41  is a perspective view showing the wheelchair lift-transfer device and the patient maneuvered to transfer the patient into a conventional wheelchair. 
         FIG. 42  is a perspective view showing the wheelchair lift-transfer device and the patient engaged in transfer with a conventional wheelchair. 
         FIG. 43  is a perspective view showing the patient after transfer into a conventional wheelchair and the wheelchair lift-transfer device removed. 
         FIG. 44  is a perspective view showing the wheelchair lift-transfer device with double telescoping columns fully extended with the patient supported in a standing position. 
         FIG. 45  is a perspective view showing the wheelchair lift-transfer device with double telescoping columns fully retracted allowing the seated patient to sit at a normal height table. 
         FIG. 46  is a perspective view showing the wheelchair lift-transfer device and patient engaged in transfer with a conventional bed. 
         FIG. 47  is a perspective view showing the wheelchair lift-transfer device configured as a rear entry power drive wheelchair that is being wirelessly remotely controlled by the patient from a conventional bed. 
         FIG. 48  is an elevation view showing an embodiment of the wheelchair lift-transfer device lifting a conventional wheelchair for insertion of the wheelchair into a vehicle. 
         FIG. 49  is a similar view showing the wheelchair lift-transfer device with lower base portion supporting the wheels and with the extended upper lift portion attached to a vehicle mounted sliding carriage which is extended. 
         FIG. 50  is a similar view showing the wheelchair lift-transfer device with wheeled lower base portion lifted by retracted columns with the wheelchair lift-transfer device attached to and supported by the vehicle mounted sliding carriage when extended. 
         FIG. 51  is a similar view showing the wheelchair lift-transfer device with the vehicle mounted sliding carriage retracted so the wheelchair lift-transfer device has moved inside the vehicle. 
         FIG. 52  is a rear elevation view of the vehicle showing both a conventional wheelchair and an embodiment of the wheelchair lift-transfer device stored within the vehicle. 
         FIG. 53  is a fragmented cut-away side elevation view of the vehicle showing both a conventional wheelchair and an embodiment of the wheelchair lift-transfer device stored within the vehicle. 
         FIG. 54  is a perspective view of an embodiment of the wheelchair lift-transfer device incorporating the U-shaped lifting frame. 
         FIG. 55  is a fragmentary perspective view of the same embodiment of the wheelchair lift-transfer device showing the exposed U-shaped lifting frame, supporting rollers, rotation drive belt, rotation drive motor, and rotation drive pulley. 
         FIG. 56  is a perspective view of the rotation drive belt in the shape required to wrap around the U-shaped lifting frame and the rotation drive pulley. 
         FIG. 57  is a perspective view of another embodiment of the patient lift-transfer device configured for placement of a patient facing forward on the Right Hand side of an aircraft isle way and the U-shaped frame opened rearward. 
         FIG. 58  is a plan view of the same embodiment with the u-shaped frame rotated 90-degrees and the wheeled base extended to maximum width. 
         FIG. 59  is a plan view of the same embodiment with the wheel support arms pivoted to produce a narrow width wheeled base and with the U-shaped support frame located to be more nearly centered over the narrowed base. 
         FIG. 60  is a perspective view of the same embodiment of the patient lift-transfer device as viewed from the lift column end. 
         FIG. 61  is a fragmentary cut-away perspective view of the U-shaped lifting frame as it serves as a curved track passing through the series of supporting rollers. 
         FIG. 62  is a perspective view of one of the U-frame support roller assemblies. 
         FIG. 63  is a hidden-line view of one of the U-frame support roller assemblies. 
         FIG. 64  is a fragmentary perspective view of the lifting column 
         FIG. 65  is a fragmentary perspective hidden-line view of the lifting column showing the positions of upper and lower support rollers within. 
         FIG. 66  is a fragmentary perspective view of the upper end of the stationary outer column and support rollers located therein. 
         FIG. 67  is a fragmentary perspective view of the lower end of the inner lifting column and support rollers located therein. 
         FIG. 68  is a similar fragmentary perspective hidden-line view of the lower end of the inner lifting column and support rollers located therein. 
         FIG. 69  is a cut away side view of the Lift transfer device. 
         FIG. 70  is a fragmentary perspective cut away view of the upper lifting column assembly. 
         FIG. 71  is a fragmentary perspective cut away view of the lower lifting column assembly mounted in the support bracket. 
         FIG. 72  is a perspective view of the ball-screw assembly with support tube, back-drive brake and crank assemblies. 
         FIG. 73  is a perspective view of the ball-screw with ball-nut and ball bearing assemblies. 
         FIG. 74  is a fragmentary perspective enlarged view of the ball-screw, the bearing support collar and the ball-nut assembly. 
         FIG. 75  is a fragmentary perspective enlarged view of the U-frame support housing with protruding ball-screw shaft and core portion of the back drive brake. 
         FIG. 76  is a similar fragmentary perspective enlarged view of the U-frame support housing with protruding ball-screw shaft, the core portion removed and the spring of the back-drive brake exposed. 
         FIG. 77  is a fragmentary cut-away perspective view of the upper end of the lifting column, showing the flat side roller tracks of the inner column. 
         FIG. 78  is a perspective view of the back-drive brake core. 
         FIG. 79  is a perspective view of the back-drive brake spring. 
         FIG. 80  is a perspective view of the back-drive brake drum. 
         FIG. 81  is a fragmentary perspective view of the lower end of the lifting column assembly poised for insertion into the open socket of the wheeled base assembly. 
         FIG. 82  is a fragmentary perspective hidden-line view of the open socket area of the wheeled base assembly. 
         FIG. 83  is a cut away side view of the lifting column installed in the support bracket and revealing portions of the inner parts. 
         FIG. 84  is a perspective view of the underside of the lift transfer device with the wheel support arms extended to provide maximum base width. 
         FIG. 85  is a perspective view of the underside of the lift transfer device with the wheel support arms retracted to provide minimum base width. 
         FIG. 86  is a fragmentary perspective enlarged underside view of the front wheel arm junction (under the lift column end of the wheeled base) showing the rotation control plate in the non-restricted position and the wheel support arm retracted to the narrow width. 
         FIG. 87  is a fragmentary perspective enlarged underside view of front wheel arm junction (under the lift column end of the wheeled base) showing the rotation control plate in the non-restricted position and the wheel support arm extended to the wide width (the wheel arm synchronizing link plate omitted). 
         FIG. 88  is a fragmentary perspective enlarged underside view of the front wheel arm junction (under the lift column end of the wheeled base) showing the rotation control plate in the restricted position and the wheel support arm extended to the wide width (the wheel arm synchronizing link plate omitted). 
         FIG. 89  is a fragmentary perspective enlarged topside view of the wheeled base showing the rearward junction of the wheel support arm, the closed (capped) socket and a portion of the stop arm. 
         FIG. 90  is a side cut away view through the rearward end of the base, showing portions of the capped socket and the stop arm. 
         FIG. 91  is a fragmentary perspective enlarged underside view of the wheeled base (the wheel arm synchronizing link plate omitted) showing the rearward junction of the wheel support arm with stop arm and the wheel support arm extended for maximum base width position. 
         FIG. 92  is a fragmentary perspective enlarged underside view of the wheeled base showing the rearward junction of the wheel support arm and a portion of the wheel arm synchronizing link plate. 
         FIG. 93  is the first of a series of (4) top views of the lift transfer device, this view showing the U-shaped lifting frame rotated to open to the rear of the lift-transfer device while centered over the base with the wheel arms extended. 
         FIG. 94  is a similar view showing the U-shaped lifting frame rotated to open to the rear of the lift-transfer device while shifted to the offset location over the base with the wheel arms extended. 
         FIG. 95  is a similar view showing the U-shaped lifting frame rotated 90-degrees to open to the side of the lift-transfer device while shifted to the offset location over the base with the wheel arms extended. 
         FIG. 96  is a top view showing the U-shaped lifting frame rotated to open to the rear of the lift-transfer device while shifted to the offset location to be centered over the base with the wheel arms retracted. 
         FIG. 97  is a perspective frontal view of the configuration of shown in  FIG. 93 . 
         FIG. 98  is a perspective frontal view of the configuration of shown in  FIG. 96 . 
         FIGS. 99-103  are a series of views showing the lift transfer device application and a patient. 
         FIG. 99  is a frontal view of the lift transfer device and a patient in position to remove the patient from a conventional wheelchair. 
         FIG. 100  is a perspective view of the lift transfer device and a patient in position to remove the patient from a conventional wheelchair. 
         FIG. 101  is a side view of the lift transfer device and a patient in position to remove the patient from a conventional wheelchair. 
         FIG. 102  is a frontal perspective view of the lift transfer device and a patient in position centered over the base set for narrow width. 
         FIG. 103  is a side view of the lift transfer device and a patient in position centered over the base set for narrow width. 
         FIG. 104  is a left-rear perspective view of one embodiment of the patient wheelchair lift-transfer device configured as a rear entry power drive wheelchair, having an articulating patient support frame and knee/foot support housing. 
         FIG. 105  is a left side view of the lift transfer device of  FIG. 104  with patient supported by knee/foot housing and a sling attached to articulating patient support frame. 
         FIG. 106  is a fragmentary front left perspective view a patient lift transfer device having a caregiver support bar which is stored in upper position. 
         FIG. 107  is a left front perspective view showing the lift transfer device transporting both a patient and a caregiver. 
     
    
    
     Certain terminology will be used in the following description for the convenience in reference only, and will not be limited. For example, the word “front” will refer to the side of the wheelchair lift-transfer device that faces the pair of double telescoping lifting columns that is opposite the side from which the cantilevered horizontal seat support arms extend; this being the side facing the lower right of  FIG. 1 . 
     With respect to the wheelchair lift-transfer device, the abbreviation “RH” which means “right hand” and “LH” which means “left hand” as related to the patients right hand or left hand as he or she is supported in the wheelchair lift-transfer device while seated and facing in the same direction as the wheelchair lift-transfer device “front” faces. The words “inwardly” and “outwardly” will refer to directions toward and away from, respectively the geometric center of the wheelchair lift-transfer device and designated parts thereof. Said terminology will include the words specifically mentioned, derivatives thereof, and words of similar import. 
     DETAILED DESCRIPTION 
     Referring to  FIGS. 1-4 , there is illustrated one embodiment of the wheelchair lift-transfer device  10  (herein-after referred to as the “transporter” for convenience) configured as a rear entry power drive wheelchair. The joystick drive, lift and actuator control module  11  in  FIG. 2  is mounted to bracket  12  in  FIG. 1 . 
     The transporter  10  includes a wheeled base assembly  13  having an upright assembly  14  projecting therefrom. The upright assembly  14  in turn mounts thereon a removable seat  15  and back support  16 , the latter being used for receiving an occupant/patient  18  ( FIG. 34 ) for transporting by the transporter  10  and transfer to and from the transporter  10 . The wheeled base assembly  13  includes a generally rigid and rearwardly-opening U-shaped horizontally extending wheeled base  17  is defined by the upright assembly  14  at the front  19  and a pair of generally parallel and rearwardly extending rear wheel support arms  20  and  21 . These rear wheel support arms are sidewardly spaced apart and define a rearwardly opening space  22  that is optionally adjustable in width therebetween to permit the base  13  to provide an opening that is wide enough to straddle a chair  23  ( FIG. 38 ) or a patient  18  lying on the floor ( FIG. 34 ) and optionally defines an overall width that is narrow enough to pass through a doorway  271  ( FIG. 54 ) or fit between opposite side-wheels of some conventional wheelchairs  24  ( FIG. 42 ). Each rear wheel support arm  20  and  21  has a wheel  25  or roller mounted adjacent the rear free end  26  thereof. In the embodiment of  FIG. 1 , these rear wheels are conventional caster wheels  27 . 
     The upright assembly  14  includes a pair of columns  30  and  31  connected to and spaced apart by cross beam structures  32  and  33  which extend horizontally transversely across the transporter  10  adjacent the front side thereof with the lower cross beam structure  33  being elevated enough to allow space  35  underneath for passage of the legs  37  of a patient  18  that is lying on the floor ( FIG. 35 ). The upright assembly  14  also has a pair of front side support arms  39  and  40  or brackets which project forwardly a small extent in cantilevered relation to the pair of columns  30  and  31 . These arms  39  and  40 , adjacent the free ends thereof  41  mount thereon front support rollers  43  and  44 . In the embodiment of  FIG. 1 , these rollers are wheels driven by electric drive-motors  45  and  46 . In the embodiment of  FIG. 31  the front support rollers are caster wheels  49  and  50 . 
     The upright assembly  14  includes a pair of vertically elongate and telescopic support post assemblies  30  and  31 , each including a vertically elongate lower post  51  and  52  to which a respective one of the rear wheel support arms  20  and  21  is attached via a respective four-bar horizontally pivoting linkage  53  and  54  ( FIG. 4 ), the combination forming the U-shaped wheeled base  13  from which the upright assemblies  30  and  31  project upwardly in cantilevered relationship therewith. In this regard, the lower posts  51  and  52  are joined together in sidewardly or laterally spaced relation by the lower cross beam structure  33 . Vertically elongate middle posts  56  and  57  are slidably telescopingly positioned within and project upwardly out of the lower posts  51  and  52 . Vertically elongate upper posts  60  and  61  are slidably telescopingly positioned within and project upwardly out of the middle posts  56  and  57 . A double-jackscrew drive  63  or lifting unit is disposed interiorly of each post assembly  30  and  31  (described later in reference to  FIGS. 6-14 ) to selectively extend and retract the lower posts  51 / 52 , middle posts  56 / 57  and upper posts  60 / 61 . 
     The support post assemblies  30  and  31  are disposed adjacent opposite sides of the transporter  10  adjacent the front corners  64  and  65  thereof, and at the upper ends  66  and  67  thereof are respectively joined to horizontally elongate seat support arms  68  and  69 . The pair of seat support arms  68  and  69  then project rearwardly in cantilevered relationship away from the support post assemblies  30  and  31  in generally parallel relationship adjacent opposite sides of the transporter. One of the seat support arms  68  has the joystick module mounting bracket  12  attached thereto for ready access by the patient&#39;s arm. The seat support arms  68  and  69  more particularly are supported on the upper posts  60 / 61  so as to move vertically therewith, and rigidly joined together in sidewardly spaced relation by the upper cross beam structure  32  and a secondary beam structure. 
     Considering now the seat support assembly  73  ( FIG. 3 ), the same includes a seat portion  15  and a backrest portion  16 , both of which are preferably connected to the seat support arms  68  and  69  by elongate flexible straps  77   a ,  77   b ,  77   c ,  77   d ,  78   a  and  78   b . Two of the set of four straps supporting the seat are pivotally attached to each respective support arm at the strap upper end  80  thereof and have the length-adjuster portion  79  of a conventional vehicle-type seat belt buckle or clasps  81   a ,  81   b ,  81   c  and  81   d  attached at the strap lower end  82  thereof. The seat  15  has the four mating buckle portions  83   a ,  83   b ,  83   c , and  83   d  of the seat belt buckles attached thereto adjacent the four corners thereof. Each support arm  68  and  69  has a backrest support strap  78   a  and  78   b  attached at the rearward end thereof, with one strap  78   b  having the adjuster portion  79  and buckle  84  attached at the free end thereof and the other strap  78   a  having the mating buckle  85  attached at the free end thereof. The straps  78   a  and  78   b , when mated, pass through openings  86  and  87  in the backrest  16 , adjustably securing the backrest to the support arms  68  and  69 . 
     To power the transporter  10 , the lower crossbeam structure  33  of the embodiment of  FIG. 1  includes a compartment in which power supply batteries  170  are stored. The joystick driving control module  11  ( FIG. 2 ) includes the operator controlled driving control joystick  90  and switches  91  for the lift up-down control and the rear wheel support arm in-out control. 
     The upper crossbeam structure  32  is supported at each end by the pair of upper posts  60  and  61  and comprises channel shaped housings  92  and  93  for supporting the lift motor  95 , the lift motor release mechanism  96 , and encloses the hexagon cross shaft  98  and the height sensing switch assembly  99  by included removable covers  100  and  101  ( FIG. 2 ). 
     Looking upwardly at the front portion of the transporter  10  in view ( FIG. 4 ), RH  102  and LH  103  linear actuators for moving the rear wheel support arms  20  and  21  and the motor control power module  105  that receives commands from the joystick control module  11 , are revealed. The motor control power module  105  provides proportioned power to all of the transporter&#39;s  10  several motors as directed by patient  18 /operator input to the joystick control module  11  and the power module&#39;s internal microprocessor  106 . One end  107  of each linear actuator  102  and  103  is pivotally mounted to the U-shaped tube structure  108  that attaches to and spans between the pair of lower posts  51  and  52 . Each of the rear wheel support arms  20  and  21  are respectively mounted to a 4-bar linkage module  53  and  54  that causes the rear wheel support arms  20  and  21  to be adjusted sidewardly in generally parallel relationship while maintaining cantilevered support of the upright assemblies  14 . 
     Now referring to  FIGS. 5-14 , transporter  10   b  ( FIG. 5 ) shows the 4-bar pivoting linkages  53  and  54  are rotated respectively by shaft  8  and arm  6  assembly and shaft  9  and arm  7  assembly. The double telescoping upright assemblies  14  include lower posts  51  and  52 , wherein slides the middle posts  56  and  57  and the upper posts  60  and  61  slides within the middle posts  56  and  57  respectively. A double jackscrew assembly  110  ( FIG. 8 ), within each upright  30  and  31 , has a small inner screw  111  having a smaller threaded end portion  112  that is non-rotatingly securely attached to the bottom horizontal wall  113  of the lower post  51  and  52  ( FIGS. 7 and 12 ) by a nut  114  threadingly secured to the smaller threaded portion  112  of the inner screw  111 , below the bottom wall  113 . The middle post  56  and  57  has securely attached thereto at the lower end  114  thereof a pair of middle tube support moldings  115   a  and  115   b  and the upper post  60  and  61  has attached at the lower end  116  thereof an outer screw large nut molding  117 . As seen in  FIG. 12 , the middle tube support moldings  115   a  and  115   b  and the outer screw large nut moldings  117  of the double jack screw assemblies  110  have therein assembled large support roller assemblies  120  and small support roller assemblies  121 . The roller assemblies  120  comprise a roller  122 , a bearing  123  and an axis pin  124 . The large rollers  120  ( FIG. 12 ), roll against the inner surface  125  of narrow sides of the lower  51  and  52  and middle  56  and  57  posts. The small rollers  121 , roll against the inner surfaces  126  of the wide sides of the lower  51  and  52  and middle  56 , 57  posts ( FIGS. 6 and 7 ). 
     Referring to FIGS.  7  and  9 - 11 , secured to the upper end  127  of each outer large jack screw  128  is a molded spline bushing  129  that rotates with the large outer screw  128 . The external spline configuration  130  on the molded spline bushing  129  is larger in diameter then the outer threads  132  of the large outer jack screw  128 . Secured to the lower end  131  of each outer jack screw  128  is a jack screw small nut molding  132  that also rotates with the outer jack screw  128 . The jack screw small nut molding  132  includes a flange ring  133  that is captured within a mating groove  134  in the pair of middle tube support moldings  115   a  and  115   b  and is fitted so as to allow free rotation therein. Each jack screw assembly  110  includes a spline tube  136  having an internal spline configuration  137  that matingly matches the external spline configuration  130  on molded spline bushing  129  portion of the large outer screw  128  and is fitted so that the outer screw  128  can move up and down within the spline tube  136  while continually transmitting rotational torque between the spline tube  136  and the large outer screw  128  so that they rotate equally. The lower end  139  of the spline tube  136  slidingly rests on the outer screw large nut molding  117  while the upper end  140  of the spline tube  136  has inserted therein a hexagon-bore  159  spline tube driver  141 . The spline tube driver  141  includes an external spline configuration  142  that matingly matches the internal spline  137  of the spline tube  136 . The spline tube driver  141  includes a flange  202  that supports spline tube driver  141  on the upper end  143  of the spline tube  136 . Each spline tube driver  141  has a short vertical hexagon shaft  135  matingly inserted within the hexagon bore thereof. 
     Referring to  FIGS. 15 and 16 , the lift motor  95  is a combined motor  144  and gear reducer  145  that is mounted between sections of the upper crossbeam structure  146  and  147 . To the right of the lift motor the exposed (handle) portion powered lift release lever  148  projects forwardly through an opening  149  in the small cover  100  section of the upper cross beam structure  32 . The narrow sides  150  of the lower posts  51  and  52  and the middle posts  56  and  57  have adjacent the upper ends thereof, mounted thereon, roller support housings  151  each having mounted within large support rollers  152  for rollingly supporting the forces from the outer surface  153  of the middle  56  and  57  and upper posts  60  and  61  that are a result of the substantial cantilevered loads carried by the pair of seat support arms  68  and  69 . The wide sides  154  of the upper ends of the lower  51  and  52  and middle posts  56  and  57  include plates  155   a  and  155   b  that capture the axles  156  of smaller side support rollers  157  that rollingly support and guide the wide sides  158  of the middle  56  and  57  and upper  60  and  61  posts. 
     Referring to  FIGS. 17-20 , rotation of the hexagon shaped cross-shaft  98  extends lifting power from the lift motor  95  to turn each of the outer jack screws  128   a  and  128   b  of the double jack screw assemblies  110   a  and  110   b  that are disposed within each of the pair of support columns  30  and  31 . The center output shaft  160  of the lift motor gear reducer  145  is hollow which allows the hexagon shaped cross shaft  98  to pass through without interference. The RH side of the lift motor  95  hollow output shaft  160  has an extended portion  161  wherein a portion of the extension  161  is notched away to form a driving cross-slot  162 . The power link  163  having a hexagon shaped bore  164  slidingly mounts on the hexagon cross shaft  98  and is fitted so that the power link  163  can move rightwardly  164  and leftwardly  165  on the hexagon cross shaft  98  while continually transmitting rotational torque between the power link  163  and the hexagon cross shaft  98  so that they rotate equally. The power link  163  includes projections  166  on one end that fittingly match the shape of the driving cross slot  162  of the lift motor output shaft  160 . The opposite end of the power link  163  has a radial slot  167  that receives the sides of the forked ends  168  of the lift power release lever  148 . A compression spring  168  mounted between the power link  163  and the adjacent upper post  60 , forces the power link  163  to slide leftwardly  165  towards the lift gearmotor  95  so that the projections  166  of the power link will engage the driving cross slot  162  in the lift gearmotor output shaft  160  thereby turning the power link  163  and cross shaft  98  when the lift motor  95  turns while the power link  163  and gear motor output shaft  160  are engaged for normal power lift operation. 
     If the lift motor  95  should fail or the battery  170  be discharged the lift can be operated manually by disengaging the power link  163  from the lift motor shaft  160 . To disengage, the exposed end  171  of the lift power release lever  148  must be rotated leftwardly  165  about a vertical axis  172  established by the vertical edge  173  of the opening  149  in the removable cover  100  through which the handle portion  174  of the lift power release lever  148  passes, so that the release lever forks  168  slide the power link rightwardly  164  on the hexagon cross shaft  98  and thereby compressing the spring  168 . The operator then pushes rearwardly on the outer end  175  of the release lever  148  so that the ends  176  of the release lever forks  168  penetrate the two openings  177  and  178  in rearward side of the cross beam channel  179 . When the operator releases the lever  148  the compression spring  168  forces the power link  163  leftwardly thereby applying force to the release lever  148  so that it is held against the leftward edges  180  and  181  of the two openings  177  and  178  in the channel wall  182  and the opening  149  on the cover wall  183 . The fork arms  168  captured in the power link radial slot  167  thereby holds the power link  163  in the rightward disengaged position  184 . The operator then inserts hexagon shaft  185  of the manual lift crank handle  186  into the hexagon shaft coupler  187  through an opening in the top surface  188  of the left hand upper post  61 . 
     Lift Operation: When either the hand crank  186  or operating the power lift motor  95  is engaged with the hexagon shaft  98  the rotation of the hexagon shafts  98  and  135  cause the spline tubes to turn, which causes the large outer jackscrews  128  to turn, causing the lift  203  to raise or descend. When the large outer jack screws  128  turn the small nut portion  132  secured to the lower end of the outer jack screw  128  likewise turns. When the small nut  132  turns on the stationary (non-rotating) small jack screw  111 , it causes the small nut  132  to move upwardly by following the helical track  191  of the thread of the small jack screw  111 . The climbing small nut  132 , in-turn lifts both the large outer jack screws  128  and the pairs of middle tube support moldings  115 . The middle tube support moldings  115  in-turn lifts the middle posts  56  and  57 . The outer jackscrew  128  being lifted by the small nut, while rotating within the middle tube support moldings  115  causes the outer screw large nut molding  117  to move upwardly by following the helical track  190  of the thread of the outer screw large nut molding  117 . The outer screw large nut molding  117 , respectively supporting the spline tubes  136  and being attached to the respective upper posts  60  and  61 , lifts the spline tubes  136  and the upper posts  60  and  61 . The lifting pair of upper posts  60  and  61 , having seat support arms  68  and  69  attached at the upper ends thereof causes the patient/operator seat  73  to move upwardly. Reversing the direction of rotation of the rotating lift parts will cause the patient/operator seat  73  to move downwardly. 
     Now referring to  FIGS. 21-24 , the horizontal hexagon shaped cross shaft  98  and the vertical hexagon shafts  135  are rotationally linked by a matching pair of bevel gears  194   a, b  and  195   a,b  at each end of the horizontal cross shaft  98 . The bevel gear  194   b  mounted on the LH end of the horizontal hexagon shaft  98  mates with the vertical shaft  135  bevel gear  195   b  on the inward side of the LH gear block  196  and the bevel gear  194   a  mounted on the RH end of the horizontal hexagon shaft  98  mates with the vertical shaft  135  bevel gear  195   a  on the outward side of the RH gear block  197 , thereby causing both outer jack screws  128  to rotate in the same direction about their respective vertical axis  198 . The bevel gears  194  and  195  are supported within radial bearings  200  which are in-turn supported by being mounted in respective gear blocks  196  and  197 . Each gear block  196  and  197  is securely mounted within the respective right hand  60  or left hand  61  upper posts. The vertical hexagon shaft  135  of the left hand jack screw assembly  201  matingly supports a hexagon coupler  187 . The hexagon coupler  187  is made available for optional connection of the hand crank assembly  186  when needed. The hexagon shaft  185  portion of the hand crank assembly  186  can be matingly inserted into the hexagon coupler  185 . Turning the inserted hand crank  186  will cause the vertical  135  and horizontal shafts  98  to turn, if the lift motor  95  has been disengaged. 
     Now referring to  FIGS. 25-30 , the left hand portion of the upper crossbeam  32  through which a portion of the horizontal hexagon cross shaft  98  passes, the hexagon cross shaft  98  has a worm gear  204  matingly attached thereon so that as the shaft  98  turns the worm gear  204  turns with it. The worm gear  204  has screw-like helical gear teeth  205  that are engaged into matching helical gear teeth  206  formed along the length of the forward side  207  of a slidable rack  208  so that when the worm gear  204  turns the engaged helical gear teeth  205  and  206  cause the rack  208  to slide either leftward or rightward. The cross beam channel  93  has attached thereto a bracket  210  having a guide track  211  along its full length from left to right. The slidable rack  208  is also engaged with the track  211  so that the rack&#39;s  208  left-right motion is guided thereby keeping the rack&#39;s spiral teeth  206  engaged with the spiral teeth  205  of the worm gear as the worm gear  204  turns and the rack  208  moves along the track  211 . The bracket  210  has a rearward vertical wall  212  whereon electrical switches  214 ,  215 ,  216  and  217  are mounted. Actuation of these switches provides signals to the motor power and logic control module  105  through which information is used by the control logic for safe and complete operations. The rack  208  has a raised rearward portion  219  that interferes with the switch rollers  220  so that when the raised portion  219  is located under a given switch the switch roller  220  is thereby lifted, actuating the internal contacts  221  of that switch. The worm gear  204  turns and the rack  208  moves in direct proportion to the lift motion distance (upwardly or downwardly). When the rack  208  has moved fully rightward on the track  211 , the far right switch  214  is activated by contact with a raised portion  219  of the rack  208  whereby the actuation of the far right switch  214  sends a signal to the motor power and logic control module  105  indicating that the transporter&#39;s lift structure  203  is (downwardly) fully retracted. When the rack  208  has moved fully leftward on the track  211 , the far left switch  217  is activated by contact with a raised portion  219  of the rack  208  whereby the actuation of the far left switch  217  sends a signal to the motor power and logic control module  105  indicating that the transporter&#39;s lift structure  203  is (upwardly) fully extended. 
     There are two other switches  215  and  216  located between the far right and far left switches. These switches are located to sense the location of the lift  203  height relative to certain lift height zones. The second switch  215  from the right, when actuated while the third switch  216  from the right and the far left  217  switches are not actuated, will indicate that the lift height is in a low height zone, wherein the controller is programmed to allow the operator patient  18  to drive the transporter  10  at up to full speed. The second  215  and third  216  switches from the right, when actuated while the far right  214  and far left  217  switches are not actuated, will indicate that the lift height is in a medium height zone, wherein the controller  105  is programmed to allow the operator patient  18  to drive the transporter  10  at up to a preset reduced speed limit. When the lift  203  is in the low and medium height zones, the switches  220  associated with the rear wheel arm actuators  221  and  222  must also be actuated so that both rear wheel support arms  20  and  21  are confirmed to be in the full-wide position as indicated by the respective wheel arm switches being actuated. If these arm location indicating switches  220  are not actuated the stability of the transporter is suspect and the motor power and logic control module  105  is programmed to limit the patient  18  driving speed to very slow. If the rear wheel support arms  20  and  21  position sensing switches  220  are not both actuated and the lift  203  is in the upper most height zone (wherein only the far left  217  and third from right  216  switches are actuated) the motor power and logic control module logic  105  is programmed to NOT allow the operator patient  18  to drive the transporter  10 . The operator  18  must move both rear wheel support arms  20  and  21  to the full-wide position or reduce the height of the lift  203  into a lower zone before the transporter  10  can be driven. The transporter control system  105  also includes an inclinometer  230  that senses the angular deviation of the wheeled base assembly  13  of the transporter  10  from horizontal orientation. When the wheeled base assembly&#39;s  13  angular orientation with respect to horizontal exceeds preset angular deviation limits various operations will be limited, such as the lift  203  will not be allowed to extend or the transporter  10  driving speed will be reduced or driving is not allowed until the lift  203  height is reduced. 
     A version of the transporter  10   a  without power driving capability is illustrated in  FIG. 31 , comprising the same horizontal base  13   a  and upright assembly  14   a  with double telescoping lifting posts  30   a  and  31   a  except the components required for power driving have been omitted and front caster wheels  232  are mounted to the upright assembly  14   a . This version is operated primarily by a caregiver who will push or pull the transporter  10   a  to move it horizontally on the support surface or floor. Optionally, the non-power drive transporter  10   a  has manually operated rear wheel support arm  21  width adjustment as seen in  FIGS. 32 and 33 . Shaft  9  rotates 4-bar pivoting linkage  54  by pivoting arm assembly  7  which is secured at the upper end thereto. Within arm  7  assembly a nut  4  is pivotally secured. A bracket  2  is secured to post  52  having a bushing  1  pivotally secured therein. Hand-crank  3   b  turns threaded shaft  5  within bushing  1  and nut  4  thereby pushing or pulling nut  4  along threaded shaft  5 . Movement of nut  4  in turn moves arm  7  which rotates shaft  9  and the pivoting 4-bar linkage which in turn moves the rear wheel support arm  21  inward or outward. 
     Now referring to  FIGS. 34-43 : When a patient has fallen to the floor, the transporter can be used to raise the patient. The caregiver moves the patient into a face up orientation with body positioned straight (as if standing), then places the seat board  15  under the patient  18  ( FIG. 34 ). The transporter  10  is then moved to straddle the patient  18  ( FIG. 35 ) so that the patient&#39;s hips  235  are located substantially between the rear wheels  236  and lower legs  37  pass under the lower cross beam structure  33 . The elongate flexible straps  77  supported by the seat support arms  68  and  69  are attached to the seat  15  by attaching the length adjuster portions  79  to the buckle portions  83  of the seat board  15  and the back support belt assembly  78  is placed under the patients back  237 . The caregiver then assists the patient to raise their head and torso to a seated position ( FIG. 36 ) by tightening the back support belt  78 . With the patient held in a seated orientation, the caregiver raises the lift  203  ( FIG. 37 ) by operation of the lift motor  95  or hand crank  186 . Since the elongate flexible straps  77  are likely fully extended, the caregiver may lower the patient on to a temporary support structure  23  ( FIG. 38 ) and then lower the lift  203  additionally ( FIG. 39 ) to allow the straps  77  to be adjusted to a shorter length. Then the patient  18  can be lifted off the temporary support structure  23  with the seat board  15  (and patient) now able to reach a much higher elevation ( FIG. 40 ). The transporter  10  can then be moved into position ( FIG. 41 ) to transfer the patient to be supported by another surface such as a conventional wheelchair  24  ( FIG. 42 ) or bed ( FIG. 46 ). Then the transporter can be moved away leaving the patient supported by another device ( FIG. 43 ,  47 ). 
       FIG. 44  illustrates the extreme lifting range potential of the double telescoping lifting columns  30  and  31  wherein the lift  203  can be raised high enough to bring a patient  18  to a standing position when elongate straps  238  are configured as a sling  239  suitable for lifting by supporting the patient&#39;s waist, buttocks and upper legs.  FIG. 45  illustrates the contrasting lower limit of the range wherein the lift  203  can be lowered enough to position the lift columns under a standard height table  240 . 
       FIG. 46  illustrates a patient positioned on a bed  242  by maneuvering the transporter  10  patient/seat support arms  68  and  69  over the bed  242 . The patient  18 , when released from the seat support straps  77  thereby being separated from the transporter  10 , can use the handheld wireless controller  243  to drive the transporter  10  away from the bed  242  ( FIG. 47 ) for storage in another location. 
       FIG. 48  illustrates a version of the transporter  10   b  attached to a conventional wheelchair  24 , having lifted the wheelchair  24  to a height sufficient to move the wheelchair  24  into a vehicle  245  by rolling the transporter  10   b  towards the vehicle  245 .  FIG. 49  illustrates the transporter  10   b  lift  203   b  extended upwardly and attached to an horizontally extendable carriage arm  246 , which can be a roller slide mechanism or a powered linear actuator that is supported by the vehicle  245  and is either manually or power extended outwardly  247  to engage with the raised transporter lift arms  68  and  69 .  FIG. 50  illustrates the lift  203   b  having been retracted and since the lift arms  68  and  69  are attached to the carriage arm  246 , the base assembly  248   b  of the transporter  10   b  lifts off the previously supporting surface  250  to a height sufficient to move the transporter  10   b  into the vehicle  245 .  FIG. 51  illustrates the vehicle carriage arm having been either manually or power retracted  249  thereby moving the transporter  10   b  into the vehicle  245 .  FIGS. 52-53  illustrate both the conventional wheelchair  24  and transporter  10   b  stored side by side within the vehicle  245  with the transporter  10   b  located under the vehicle carriage arm  246 . Of course this procedure can be reversed to move the transporter  10   b  and wheelchair  24  from the vehicle  245  to the lower level surface  250  outside the vehicle. 
     Now considering  FIGS. 54-56 . These Figures illustrate another patient wheelchair-lift embodiment  110 - 1  that is similar to the wheelchair lift-transfer device  10 . Wheelchair-lift embodiment  110 - 1  utilizes a roller housing assembly  20   b - 1  and U-shaped lifting frame  28   b - 1  instead of arms  68 ,  69  as in wheelchair lift-transfer  10 . In embodiment  110 - 1  the rotation of U-shaped lifting frame  28   b - 1  is powered by electric drive motor  111 - 1 . Roller housing assembly  20   b - 1  is supported by two lifting columns  112   a - 1  and  112   b - 1  wherein lifting columns  112 - 1  are raised by power from drive motor  113 - 1  and front wheels  114 - 1  are driven by a pair of drive motors  115   a - 1  and  115   b - 1 . In this case patient  18  has control of all the motors  111 - 1 ,  113 - 1  and  115 - 1  which provides greatly increased independence for patient  18 . 
       FIG. 55  illustrates in more detail roller assembly arrangement  116 - 1 , driving belt  117 - 1  and belt driving pulley  118 - 1 . Belt  117 - 1  is attached to U-shaped lifting frame  28   b - 1  at each belt end  120   a - 1  and  120   b - 1  at attachment points  121 - 1  near the open ends  122 - 1  of U-shaped frame  28   b - 1 . Belt  117 - 1  is tensioned to lay tightly in a groove  123 - 1  in U-shaped lifting frame  28   b - 1  so it will pass through roller array  116 - 1  as frame  28   b - 1  moves there through. At central point  124 - 1  of roller housing assembly  20   b - 1 , belt  117 - 1  curves away from U-shaped frame  28   b - 1 , wraps around driving pulley  118 - 1 , and then curves back  124 - 1  into contact with U-shaped frame  28   b - 1 . As driving pulley  118 - 1  turns it moves belt  117 - 1 , the belt end  120 - 1  under tension ( 120   a - 1  or  120   b - 1 ) pulls U-shaped lifting frame  28   b - 1  through roller array  116 - 1 , thereby rotating U-shaped frame  28   b - 1  about a substantially vertical axis. Hand crank  62   b - 1  is used to optionally drive lifting screws  118 - 1  for lifting patient  18 , after disengaging electric lift driving motor  113 - 1 . 
     Referring to  FIGS. 57-103 , there is illustrated another embodiment of lift-transfer device  10 - 1  (herein-after referred to as the “air-lift” for convenience) configured as a patient lift and transfer device especially suitable for use on a commercial passenger aircraft  128 - 1 . The air-lift  10 - 1  includes wheeled base  11 - 1  having horizontal elongated frame member  12 - 1  with support bracket  13 - 1  attached at each end. Support bracket  13   a - 1  of one end is basically a mirror configuration of support bracket  13   b - 1  of the opposite end. 
     Each support bracket  13 - 1  has socket  14 - 1  for optionally receiving and supporting lifting column assembly  15 - 1  in substantially vertical orientation, horizontal projecting structure  16 - 1  for mounting caster wheel  17 - 1  and side hinge structure  18 - 1  for mounting wheel support arm  19 - 1 . Lifting column assembly  15 - 1  includes roller housing assembly  20 - 1  at the upper end  21 - 1  thereof. 
     The wheeled base  11 - 1  has wheel support arm  19 - 1  pivotally connected to hinge structure  18 - 1  of each support bracket  13 - 1 . Wheel support arms  19 - 1  each have caster wheel  17 - 1  mounted at  22 - 1  opposite the hinge end. 
     When wheel support arms  19 - 1  are extended perpendicularly from support brackets  13 - 1  ( FIGS. 57 and 58 ) this results in the widest base configuration  23 - 1 . When wheel support arms  19 - 1  are angled rearwardly from the elongated frame member  12 - 1  ( FIGS. 59 and 60 ), base  11 - 1  configuration width is reduced  24 - 1 . 
       FIG. 61  illustrates roller housing assembly  20 - 1  located at the upper end  21 - 1  of lifting column  15 - 1 , which includes: roller housing  25 - 1 , housing cover  26 - 1 , and internal guide roller assemblies  27 - 1  configured to support and guide rotatable U-shaped lifting frame  28 - 1 . Roller housing assembly  20 - 1  is attached to the lifting column  15 - 1  so that it cannot rotate independent of the lifting column  15 - 1 . 
     Guide roller assembly  27 - 1  ( FIGS. 62 ,  63 ) includes support roller  29 - 1 , two radial needle bearings  30 - 1 , upper and lower needle thrust bearings  31 - 1  and axle pin  32 - 1 . Support rollers  29 - 1  have flanges  33 - 1  that capture the upper  34 - 1  and lower  35 - 1  edges of U-shaped lifting frame  28 - 1  cross section  36 - 1 . Axle pin  32 - 1  is supported with axis substantially vertical in roller housing  25 - 1  and housing cover  26 - 1 . Needle bearings  31 - 1  at each end of guide roller assembly  27 - 1  reduce rolling friction as rollers  29 - 1  turn about their respective axle pin  32 - 1 . Needle thrust bearings  31 - 1  reduce the friction from forces vertically induced from supporting U-shaped lifting frame  28 - 1 . 
     The curved portion  37 - 1  of U-shaped lifting frame  28 - 1  can be moved through guide roller arrangement  38 - 1  within roller housing assembly  20 - 1  thereby causing U-shaped lifting frame  28 - 1  to rotate about a substantially vertical axis which changes the angular orientation to which open portion  39 - 1  of the “U”  40 - 1  faces with respect to the orientation of wheeled base  11 - 1 . 
     U-Shaped lifting frame  28 - 1  includes suspended support structures  42 - 1  that provide attachment points  43 - 1  for patient support accessories such as sling  44 - 1  ( FIGS. 107-117 ). Support structures  42 - 1  pass under roller housing  25 - 1  as adjacent curved portion  45 - 1  of U-shape  37 - 1  passes through housing  25 - 1 , directly above. 
     Lifting column assembly  15 - 1  may be rotated approximately 20-degrees about its vertical axis within socket  14 - 1  of support bracket  13 - 1  into which it is assembled if wheel support arms  19 - 1  are extended perpendicularly from the elongated frame member  12 - 1 . This rotation of lifting column assembly  15 - 1  allows for repositioning of the center axis of U-shaped lifting frame  28 - 1  for improved stability when wheeled base  11 - 1  has been widened  23 - 1 . This feature will be better described later regarding  FIGS. 93-96 . 
     Now considering the basic structure of lifting column assembly  15 - 1  ( FIG. 64-68 ), which includes inner column tube  50 - 1  and outer column tube  51 - 1  telescopingly assembled together about a common vertical axis. The upper end  52 - 1  of outer column  51 - 1  has attached roller support assembly  53 - 1  wherein support rollers  54 - 1  guide the vertical motion of inner column  50 - 1  within outer column  51 - 1  by rolling against outer surface  55 - 1  of inner column  50 - 1 . The lower end  56 - 1  of inner column  50 - 1  includes roller support assembly  57 - 1  wherein rollers  58 - 1  guide the vertical motion of inner column  50 - 1  within outer column  51 - 1  by rolling against the inner surface  59 - 1  of outer column  51 - 1 . 
     Referring to  FIGS. 69-80 , internal to inner  50 - 1  and outer  51 - 1  tubes of lifting column assembly  15 - 1  is ball-screw  60 - 1  and ball-nut assembly  61 - 1  for expanding and retracting the height column  15 - 1 . The lifting force is applied by turning crank handle  62 - 1  mounted on ball-screw  60 - 1 . 
     Ball-screw  60 - 1  turns within ball-nut  61 - 1  which is non-rotatingly supported on support tube  63 - 1  which is in turn supported on lift transfer device  10 - 1  base assembly  11 - 1 . At the top of thread portion  64 - 1  of ball-screw  60 - 1  is mounted bearing support bushing  65 - 1 . Inner race  66 - 1  of radial/thrust bearing  67 - 1  mounts on bushing  65 - 1 . The outer race  68 - 1  of radial/thrust bearing  67 - 1  supports the upper end  69 - 1  of inner column  50 - 1 . As ball-screw  60 - 1  turns it lifts bearing  67 - 1  which in turn lifts inner column  50 - 1 . Reversing the rotation of crank  62 - 1  and ball-screw  60 - 1 , lowers inner column  50 - 1 . 
     Near the top of ball-screw  60 - 1 , just under crank handle  62 - 1 , back-drive brake assembly  70 - 1  is located. Back-drive brake assembly  70 - 1  provides increased rotational friction in only one direction of rotation. Because ball-screw  60 - 1 /ball-nut  61 - 1  assemblies are inherently low-friction assemblies, the effort required to lift the patient  41 - 1  is reduced. The reduced friction can also allow the weight of the patient  41 - 1  to cause ball-screw  60  to reverse rotation (back-drive) and lower the lift  15 - 1 . The back-drive brake  70 - 1  adds enough friction to overcome the back-driving force, thereby maintaining the selected lift height. 
     Mounted on ball-screw  60 - 1  is core  75 - 1  of brake assembly  70 - 1  and mounted to the upper end  69 - 1  of inner column  60 - 1  is brake drum  76 - 1 . Mounted between core  75 - 1  and drum  76 - 1  is coiled wire spring  77 - 1  having two sections. The smaller wound section  78 - 1  fits slidingly close to core  75 - 1  outer surface  79 - 1  and the larger wound section  80 - 1  interferingly fits within drum  76 - 1  inner surface  81 - 1  with larger spring coils  80 - 1  forced to conform against inner drum surface  81 - 1 . When ball-screw  60 - 1  is rotated to lift inner column  50 - 1  smaller section  78 - 1  of spring  77 - 1  slides freely on core  75 - 1 . When ball-screw  60 - 1  is rotated oppositely to lower inner column  50 - 1 , smaller section  78 - 1  of spring  77 - 1  instantly grips tightly to core  79 - 1  which causes the entire spring  77 - 1  to rotate and larger section  80 - 1  of spring  77 - 1  to rub against inner surface  81 - 1  of drum  76 - 1  in which the resulting friction resists the back-driving rotation. 
     Referring to  FIGS. 81-93 , lifting column assembly  15 - 1  can be optionally assembled into socket  14 - 1  of support bracket  13 - 1  at either end of base assembly  11 - 1  (the end to which the lifting column is installed serves as the “front” end). 
     Outer column tube  51 - 1  is supported in the upper end  85 - 1  of socket  14 - 1  by bearing liner  86 - 1  and rests at the bottom end  87 - 1  on thrust bearing  88 - 1 . The bottom portion  87 - 1  of lifting column  15 - 1  has shaft extension  89 - 1  with flat sides  90 - 1 . A portion of shaft extension  89 - 1  projects through hole  91 - 1  in the bottom of bracket  13 - 1 . 
     Rotation control plate  92 - 1  is attached to shaft extension  89 - 1  from the underside of base assembly  11 - 1  by engaging flats  90 - 1  so that rotation control plate  92 - 1  must rotate with lifting column assembly  15 - 1  if it is rotated within socket  14 - 1 . 
     Now referring to  FIGS. 84-88 . It is advantages to shift sidewardly lifting column assembly  15 - 1  (by rotation about the column vertical axis) to improve stability of air-lift  10 - 1  when wheel support arms  19 - 1  are extended  23 - 1 . However, when wheel support arms  19 - 1  are retracted  24 - 1  to narrow the base width  24 - 1 , lift column assembly  15 - 1  must be restricted from being shifted (rotated). Rotation control plate  92 - 1 , attached to bottom  87 - 1  of lifting column assembly  15 - 1 , provides this restriction by blocking lifting column assembly  15 - 1  from rotating when wheel support arms  19 - 1  are retracted  24 - 1 . If wheel support arms  19 - 1  are extended  23 - 1 , plate  92 - 1  configuration allows lifting column assembly  15 - 1  to be rotated through the full extent of its pivotal range. In  FIGS. 95 and 96  wheel arm synchronizing link plate  93 - 1  has been omitted for clarity. 
     Now referring to  FIGS. 89-92 . It is also advantages for wheel support arms  19 - 1  to retract  24 - 1  in the rearward direction from the lift column  15 - 1  end. Therefore rearward end  94 - 1  of air-lift  10 - 1  has stop plate  95 - 1  that restricts wheel support arms  19 - 1  from retracting forwardly. 
       FIG. 89  illustrates the top side of support bracket  13   b - 1  wherein socket cap  82 - 1  is installed and wheel support arm  19 - 1  extends there from. In this junction a portion of stop plate  95 - 1  is exposed and blocking wheel support arm  19 - 1  from pivoting in one direction. At junction corner  83 - 1 , stop plate  95 - 1  has upwardly projecting pin  96 - 1  to block stop plate  95 - 1  from pivoting. 
       FIG. 90  illustrates the cut away view of socket  14 - 1  showing short mounting shaft  97 - 1  to which stop plate  95 - 1  is attached. Stop plate  95 - 1  is retained on shaft  97 - 1  by retaining cap  98 - 1  and screw  99 - 1 . 
       FIG. 91  illustrates stop plate  95 - 1  located adjacent wheel arm hinge end bracket  100   b - 1 . This view shows wheel arm  19 - 1  is blocked from pivoting forwardly (wheel arm synchronizing link plate  93 - 1  and retaining cap  98 - 1  have been omitted for clarity). 
       FIG. 92  illustrates stop plate  95 - 1  adjacent wheel arm hinge end bracket  100   b - 1 . This view shows wheel arm  19 - 1  is allowed to pivot only rearwardly. 
     Now referring to  FIGS. 93-98 ,  FIGS. 93 and 97  illustrate wheel arms  19 - 1  extended  23 - 1 , lifting support column  15 - 1  has been shifted (by rotation) sidewardly  101 - 1  so the center of U-shaped lifting frame  28 - 1  is offset to become more centrally located over base  11 - 1  widened  23 - 1  to improve stability of air-lift  10 - 1  and U-shaped lifting frame  28 - 1  is oriented to open  39 - 1  rearwardly. 
       FIG. 94  is a similar view showing lifting column assembly  15 - 1  has been shifted oppositely  102 - 1  of that shown in  FIG. 93  so that U-shaped frame  28 - 1  is located more centrally over base  11 - 1  elongated frame member  12 - 1 . In this position wheel arms  19 - 1  could be retracted as shown in FIG.  96  (if desired). U-shaped lifting frame  28 - 1  remains rotated to open  39 - 1  rearwardly, as in  FIG. 96 . 
       FIG. 95  is a similar to  FIG. 94  except U-shaped lifting frame  28 - 1  is rotated 90-degrees to open  39 - 1  to the side of air-lift  10 - 1  while shifted  102 - 1  to the offset location over base  11 - 1  with wheel arms  19 - 1  extended  23 - 1 . Since patient&#39;s  41 - 1  back would be facing outward of U-shaped frame  28 - 1  opening  39 - 1 , having lifting column assembly  15 - 1  shifted  102 - 1  more centrally over base  11 - 1  elongated frame member  12 - 1  provides greater stability when patient  41 - 1  would be rotated 90-degrees as shown in this view. 
     In  FIGS. 96 and 98  the configuration is similar to the view of  FIG. 94  showing lifting column assembly  15  has been shifted  102  oppositely of that shown in  FIG. 93  so that U-shaped frame  28 - 1  is located more centrally over base  11 - 1  elongated frame member  12 - 1 . However, in this position wheel arms  19 - 1  are shown retracted  24 - 1  so that base  11 - 1  is set at the narrow width  24 - 1  and U-shaped lifting frame  28 - 1  remains rotated to open  39 - 1  rearwardly. This configuration is suitable for transporting a patient  41 - 1  along narrow isle ways. 
     In  FIGS. 99-103  illustrate patient  41 - 1  supported by air-lift  10 - 1 . 
       FIGS. 99-101  are various perspective views of air-lift  10 - 1  engaged with a conventional wheelchair  120 - 1  wherein patient  41 - 1  is being transferred from one device to the other. In this operation wheel support arms  19 - 1  have been retracted  24 - 1  to make air-lift  10 - 1  base  11 - 1  narrow  24 - 1  which allows the rearward portion of base  11 - 1  to pass under conventional wheelchair  120 - 1 . 
     Patient  41 - 1  is seated on lifting sling  44 - 1  or a thin seat plate while in conventional wheelchair  120 - 1 . Sling  44 - 1  has flexible webbing loops  121 - 1  that attach to U-shaped lifting frame  28 - 1 . This makes air-lift  10 - 1  ready to begin supporting and lifting patient  41 - 1  so conventional wheelchair  120 - 1  can be removed from under patient  41 - 1 . 
       FIGS. 102 and 103  show patient  41 - 1  has been transferred to air-lift  10 - 1  and base  11 - 1  width has been set to narrow width  24 - 1 . Patient  41 - 1  and lifting portion of air-lift  10 - 1  are now ready to be lifted to an appropriate height to pass through a narrow aisle way. 
     Now referring to  FIGS. 104-107 , there is illustrated one embodiment of transporter  300  configured as a rear entry power drive wheelchair.  FIG. 104  shows transporter  300  with lift columns  301   a  and  301   b  extended. Mounted to support arms  302   a  and  302   b  is an articulating patient support frame  303  lockably-pivotally attached at pins  304   a  and  304   b . Support frame  303  has hooks  305   a  and  305   b  for attachment of back support sling  306 . The forward end of support frame  303  has links  307   a ,  307   b  pivotally attached at points  323   a  and  323   b  and links  308   a  and  308   b  pivotally attached at points  324   a  and  324   b . The other end of links  307   a  and  307   b  are pivotally and releasably attached to the upper end  310  of knee/foot support housing  309  at points  311   a  and  311   b . The other end of links  308   a  and  308   b  are pivotally attached to the knee/foot support housing  309  at points  312   a  and  312   b . Transporter  300  illustrates optional use of multi-directional rear wheels  313   a  and  313   b  attached to rear wheel support arms  314   a  and  314   b  to improve stability compared to castering multi-directional wheels  236  ( FIG. 36 ) shown in previously described transport embodiments. 
       FIG. 105  shows the transporter of  FIG. 104  having a patient  318  being transported. Feet  319  and knees  320  of patient  318  are supported on knee/foot support housing  309  with articulating support frame  303  locked from pivoting at pivots  304 . The upper body of patient  318  is supported by sling  306 . This patient support configuration leaves the buttocks  322  of patent  318  exposed for possible bathroom use. To lift patient  318  while keeping feet  319  resting on the floor  332  (similar to  FIG. 44 ) links  307   a  and  307   b  can be released from knee/foot support housing  309  at points  311   a  and  311   b . This will allow link  308   a  and  308   b  to pivot at points  312  and  324  when patient  318  is lifted, thereby leaving knee/foot support housing  309  and feet  319  resting on floor  332 . 
       FIG. 106  shows transporter  300  having a caregiver support bar  325  pivotally mounted at points  326   a  and  326   b  so that support bar  325  can be rotated 180 degrees to upright position  327  or downward position  328  ( FIG. 107 ). With support bar  325  in downward position  328 , both a patient  318  and a caregiver  330  can be transported. 
     The lift transfer devices of this invention can be either manually propelled, or the wheels can be power driven through a suitable drive mechanism, examples of which are disclosed in the above applications and patent. 
     Although particular preferred embodiments of the invention have been disclosed in detail for illustrative purposes, it will be recognized that variations or modifications of the disclosed apparatus, including the rearrangement of parts, lie within the scope of the present invention.