Patent Publication Number: US-8966678-B2

Title: Lift apparatus

Description:
1. TECHNICAL FIELD 
     The present invention generally relates to an apparatus for lifting and moving a person or item from one position to another, and more particularly, for lifting, transporting, and transferring a person from a wheelchair to a seat, such as in a vehicle. 
     2. BACKGROUND OF THE INVENTION 
     A person who depends on a wheelchair may face challenges when traveling and need assistance when moving from a wheelchair to a passenger seat in an aircraft, train or other vehicle. For example, in order to move from a wheelchair to a passenger seat in an aircraft, before boarding the aircraft, this person must first move from the wheelchair to a specially designed wheelchair that fits within the narrow aisle an aircraft. This transfer typically occurs in a waiting room, a departure lounge, a concourse, or on an aerobridge of an airport. After this person is moved into the specially designed wheelchair, he or she is transported onto the aircraft and into a passenger seat on the aircraft. This process requires two transfers. The first transfer is from the wheelchair to a specially designed wheelchair that fits within the aircraft&#39;s aisle. The second transfer is from the specially designed wheelchair to the passenger&#39;s seat. This multi-step transfer process often requires close physical contact with the passenger&#39;s thighs, knees and underarms, which may be an unpleasant and awkward experience for both the passenger and the person assisting the passenger, such as an airline employee. This process may also be physically onerous and injurious to the passenger being lifted or the person assisting the passenger, due to size or strength disparities between the two people. For example, an airline employee who repeatedly lifts heavy passengers from wheelchairs and into airline seats without mechanical assistance may risk injury. 
     According to one aspect, the present invention provides a lift apparatus for lifting and transferring a person from a wheelchair to a passenger seat in an aircraft efficiently, quickly, easily, and inexpensively. The apparatus allows a person assisting the passenger to lift the passenger into a passenger&#39;s seat on an aircraft while minimizing the extent of physical contact between these people. 
     3. SUMMARY OF THE INVENTION 
     On embodiment of the present invention is directed to an apparatus and a method for lifting, transporting, and transferring a person from a wheelchair to a seat in an aircraft. The present invention also facilitates lifting and transporting passengers of a wide range of sizes and weights, regardless of the passenger&#39;s size. 
     In one such embodiment, the apparatus of the present invention may be used to lift, transport, and transfer a person from a wheelchair to a seat in an aircraft quickly, easily, efficiently, and inexpensively. 
     In one such embodiment, the apparatus comprises a base frame, a lift mechanism, an overhead support arm member, an outrigger support, a hanger, and a control system. 
     The base frame may include base frame members, and a plurality of wheels. 
     The lift mechanism may include a cylindrical guide housing fixedly attached to the base frame, a lift rod telescopingly housed within the cylindrical guide housing for controlling the lift apparatus&#39;s position, a selector collar that is movable along the rotatable head into a predetermined vertical position, and a lift actuator. 
     The overhead support arm member is affixed to the lift rod and pivotably movable to a predetermined laterally extended position on a selected side of the lift apparatus, such as the right or left side of the apparatus. 
     The outrigger support comprises a laterally rotatable outrigger bar pivotably affixed to the base frame and rotatable to the selected side of the lift apparatus, and an outrigger locking mechanism for maintaining the laterally rotatable outrigger bar in a predetermined laterally extended position on the selected side of the lift apparatus. 
     The hanger is also slidably supported on the overhead support arm member and adapted to support a load, such as a person or heavy object. 
     When the outrigger locking mechanism locks the laterally rotatable outrigger bar into the predetermined laterally extended position on the selected side of the lift apparatus and when the selector collar is in the predetermined vertical position along the rotatable head, the control system activates the lift mechanism and the overhead support arm member is limited to be rotatable only to the selected side of the lift apparatus, which is the same side of the apparatus to which the outrigger support bar extends. 
     In another embodiment, the method of using the lift apparatus of the present invention includes rotating the laterally rotatable outrigger bar to a selected side of the apparatus in order to activate at least one outrigger position sensor switch associated with the selected side of the apparatus, locking the laterally rotatable outrigger bar into the predetermined laterally extended position on the selected side of the lift apparatus, moving the selector collar into the predetermined vertical position along the rotatable head that is associated with the selected side of the lift apparatus, activating the lift mechanism, elevating the overhead support arm member, and rotating the overhead support arm member to the same selected side of the lift apparatus. In yet a further embodiment, a lift apparatus is provided, comprising: 
     a base frame; 
     a lift mechanism attached to said base frame and comprising: a lift member and a lift actuator; 
     a rotatable support arm connected to said lift member wherein said lift member is operable to control a vertical position of said rotatable support arm, and wherein said support arm is movable to a laterally extended position on a selected side of said lift apparatus; 
     a support arm selector movable to a position corresponding to said selected side and to maintain said support arm on said selected side; 
     an outrigger support comprising: a laterally movable outrigger affixed to said base frame and movable to said selected side of said lift apparatus; an outrigger locking mechanism for retaining said outrigger in an extended position on said selected side of said lift apparatus; and 
     a control system for controlling said lift mechanism, wherein when said outrigger is retained in said laterally extended position on said selected side of said lift apparatus and when said support arm selector is in said position corresponding to said selected side, said control system activates said lift mechanism and said support arm is limited to be movable to said selected side of said lift apparatus. 
     While aspects of the following description relate to operation of the apparatus in transferring a person from a wheelchair to a seat in an aircraft, the invention is not to be limited to this use. 
     Further advantages of the invention will become apparent when considering the drawings in conjunction with the detailed description. 
    
    
     
       4. BRIEF DESCRIPTION OF THE DRAWINGS 
       The device and method of using the device according to several embodiments of the present invention will now be described with reference to the accompanying drawing figures, in which: 
         FIG. 1  illustrates a side view of the apparatus in accordance with an embodiment of the present invention. 
         FIG. 2  illustrates a side, close-up view of the lift mechanism of the apparatus shown in  FIG. 1  in accordance with an embodiment of the present invention. 
         FIG. 3  illustrates a rear view of the apparatus shown in  FIG. 1  in accordance with an embodiment of the present invention. 
         FIG. 4  illustrates a rear close-up perspective view of the outrigger bar of the apparatus shown in  FIG. 1  with the outrigger bar in a stored, vertical position in accordance with an embodiment of the present invention. 
         FIG. 5  illustrates a rear close-up perspective view of the outrigger bar of the apparatus shown in  FIG. 1  with the outrigger bar in a rotated, laterally extended position in accordance with an embodiment of the present invention. 
         FIG. 6  illustrates a side perspective view of the apparatus shown in  FIG. 1  with the outrigger bar in a rotated, laterally extended position in accordance with an embodiment of the present invention. 
         FIG. 7  illustrates an exploded view of a selector collar, an overhead support arm, indexing detents on the rotatable head, and a collar switch activation element for use with the apparatus shown in  FIG. 1  in accordance with an embodiment of the present invention. 
         FIG. 8  illustrates a close-up perspective view of a selector collar for use with the apparatus shown in  FIG. 1  in accordance with an embodiment of the present invention. 
         FIG. 9  illustrates a close-up front view of the selector collar shown in  FIG. 8  in accordance with an embodiment of the present invention. 
         FIG. 10  illustrates a rear close-up view of the selector collar shown in  FIG. 8  in accordance with an embodiment of the present invention. 
         FIG. 11  illustrates a side close-up view of the selector collar shown in  FIG. 8  in accordance with an embodiment of the present invention. 
         FIG. 12  illustrates a top close-up view of the selector collar shown in  FIG. 8  in accordance with an embodiment of the present invention. 
         FIG. 13  illustrates a front close-up view of the selector collar shown in  FIG. 8  moved into a predetermined neutral position on the rotatable head in accordance with an embodiment of the present invention. 
         FIG. 14  illustrates a front close-up view of the selector collar shown in  FIG. 8  moved into a predetermined uppermost position on the rotatable head in accordance with an embodiment of the present invention. 
         FIG. 15  illustrates a method of rotating the overhead support arm member to a selected side of the apparatus shown in  FIG. 1  in accordance with an embodiment of the present invention. 
         FIG. 16  illustrates a method of rotating the overhead support arm member fully rotated to a selected side of the apparatus shown in  FIG. 1  in accordance with an embodiment of the present invention. 
         FIG. 17  illustrates a method of rotating the overhead support arm member rotated towards an opposite selected side of the apparatus from that shown in  FIG. 16  in accordance with an embodiment of the present invention. 
         FIG. 18  illustrates a schematic of a control system for use with the apparatus shown in  FIG. 1  in accordance with an embodiment of the present invention. 
         FIG. 19  illustrates a close-up view of the outrigger position sensor switch of the control system illustrates in  FIG. 18  for use with the apparatus shown in  FIG. 1  in accordance with an embodiment of the present invention. 
         FIG. 20  illustrates a close-up view of the locking mechanism position sensor switch of the control system illustrated in  FIG. 18  for use with the apparatus shown in  FIG. 1  in accordance with an embodiment of the present invention, showing the locking mechanism in a locked position and the switch in a closed, activated state in accordance with an embodiment of the present invention. 
     
    
    
     Like reference numerals refer to corresponding parts throughout the several views of the drawings. 
     5. DETAILED DESCRIPTION OF THE INVENTION 
     The lift apparatus  1  according to an embodiment of the present invention may be used to lift a person or an object from one position to another. In a particular embodiment, the lift apparatus  1  may be used to move a person between a wheelchair or other assistive device and a passenger seat on a vehicle such as an aircraft. The lift apparatus  1  may be vertically and horizontally adjustable to allow for movement in multiple directions, which permits the person or object being lifted to be moved between various positions. The lift apparatus  1  may be sized to fit within an aisle of a vehicle such as an aircraft. It may also be modular and foldable so that it may be stowed in relatively small space, such as within the vehicle such as an aircraft. The lift apparatus  1  may desirably include one or more safety features to stabilize it while it is in use. These safety features mitigate the risk of the lift apparatus  1  tipping over or otherwise losing stability when, for example, an airline employee uses it to lift a heavy person from a wheelchair in an airline terminal or to place the person into a passenger seat in an aircraft. 
       FIG. 1  illustrates a side view of the apparatus  1  in accordance with an embodiment of the present invention, where the apparatus is shown in an inactive position. The lift apparatus  1  has a base frame  2 , a rotatable support arm, such as an overhead support that includes an overhead support arm  6  and a rotatable head  20 , a lift mechanism  7 , an outrigger support  14 , a lift actuator  12 , and a control system (not shown). In another embodiment, the lift apparatus  1  may also additionally comprise a support hanger  19  such as may be slidably attached to the rotatable support arm, such as to overhead support arm  6 , and a power source  23 , such as to provide power for the lift actuator and/or the control system. 
     In one embodiment, the base frame  2  is supported such as by wheels  4   a ,  4   b  and  4   c ,  4   d  (not shown) which permits the lift apparatus  1  to be moved horizontally across a surface by rolling. The wheels  4   a ,  4   b  may be any type of wheels known in the art for vehicles used for transporting and lifting a person or heavy object, such as caster wheels. In an embodiment, the base frame may also have wheel locking mechanisms for preventing rotation of the wheels. The wheel locking mechanisms may be any suitable wheel locking mechanism known in the art for vehicles used for transporting and lifting a person or heavy object. In an embodiment, the wheels may have wheel frames and wheel frame locking mechanisms  5  for preventing the wheels from swiveling. 
     The lift  1  may also include a sling or other load supporting device (not shown) affixed to the hanger  19  to facilitate lifting a person who is immobile or semi-mobile. The lift apparatus  1  may also be used with any suitable seat  41  and/or footrest  44  known in the art when used to lift and transport a person. When using the apparatus  1  to lift and transport a person who is immobile, the seat  41  and footrest  44  may provide greater physical comfort to this person. 
     The base frame  2  and rotatable support arm components such as overhead support arm  6  and rotatable head  20  may be fabricated from any suitable materials, such as aluminum, stainless steel, iron, plastic, or other material with a suitable strength to weight ratio to support the weight of a person or heavy object. In one embodiment, the base frame  2  includes base frame members  3  and a plurality of wheels  4   a - 4   d  which are attached to the base frame  2 . The base frame  2  may be formed as one uniform object or alternatively as a set of separate, discrete members connected to one another by any suitable connections or mechanical fasteners known in the art, such as welds or bolts, for example. 
     In one embodiment, the lift apparatus  1  may also have a handle bar  11  for facilitating transport of the apparatus across a surface and a bracket, such as support bracket  13  that connects the rotatable head  20  and the overhead support arm  6  to one another. The hanger  19  is supported by the overhead support arm  6 . A sling (not shown) may be affixed to the hanger  19  to facilitate lifting and moving a person or heavy object into and out of the lift apparatus  1 . 
     In an embodiment, a lift member, such as lift rod  9  may be telescopingly housed within a cylindrical guide housing  8  for controlling a vertical position of the overhead support arm  6  that is pivotably movable to a predetermined laterally extended position on a selected side of the lift apparatus, such as the left or right side of the apparatus. In such an embodiment, the overhead support arm  6  and the lift rod  9  may be rotatably connected to one another by any suitable mechanical connection known in the art, such as a bearing or bushing, for example. 
       FIG. 2  illustrates a side, close-up view of the lift mechanism  7  of the apparatus shown in  FIG. 1  in accordance with an embodiment of the present invention. The lift mechanism  7  is fixedly attached to the base frame  2 , such as by a cylindrical guide housing  8  fixedly attached to the base frame  2 , and has a lift member, such as a lift rod (not shown) that is telescopingly housed within the cylindrical guide housing  8  for controlling the height and vertical position of the support arm, including overhead support bar  6 , selector collar  10 , and lift actuator  12 . The lift member, such as lift rod  9  is used for controlling the position of the overhead support bar  6  as it is lifted. The lift mechanism  7  has a support arm selector, such as selector collar  10  that is movable with respect to the lift member and support arm, such as movable along the rotatable head  20  in a vertical direction between at least two discrete positions. In one embodiment, the lift actuator  12  may be a pneumatic or hydraulic actuator, a piston rod  31  and a cylinder  32 , screw drive actuator, motor, or any other suitable lift actuator known in the art.  FIGS. 1 ,  2 ,  4 ,  6  illustrate an embodiment of the present invention having a screw and nut type electrically powered lift actuator  12  with a lift rod  31  and a cylindrical housing  32 . 
       FIGS. 3-5  illustrate the outrigger support  14  on the lift apparatus  1  according to an embodiment of the invention. The outrigger support  14  stabilizes the lift apparatus  1  as it is used to lift a person or heavy object. The outrigger support  14  may have an outrigger, such as outrigger bar  15  that is pivotably affixed to the base frame  2  and rotatable to a selected side of the lift apparatus  1 . The outrigger support  14  has a laterally rotatable outrigger bar  15  and an outrigger locking mechanism  16  for maintaining the bar  15  in a predetermined laterally extended position on the selected side of the lift apparatus  1 , such as the left or right side of the apparatus  1 . In an embodiment, the outrigger bar  15  may be rotatable to a position slightly above a surface, such as a floor, in order to facilitate moving the lift apparatus  1  across the surface after the outrigger bar  15  has been rotated to the selected side of the apparatus. The outrigger bar  15  and locking mechanism  16  may be fabricated from any suitable materials, such as aluminum, stainless steel, iron, plastic, or other suitable rigid material. In a particular embodiment, the outrigger locking mechanism  16  includes a spring-loaded release pedal  17  and at least one position indexing notch  18  disposed on the outrigger bar  15 . The notch  18  is sized to accommodate the release pedal  17 . The release pedal  17  may be spring loaded in order to maintain the pedal&#39;s position within the notch  18  and lock the outrigger bar  15  into a desired position. The outrigger locking mechanism  16  may be released by forcibly pushing the spring loaded release pedal  17  out of the notch  18   a ,  18   b ,  18   c , which permits the outrigger bar  15  to pivot freely with respect to the release pedal  17 . In an exemplary embodiment, the outrigger bar  15  has three notches  18   a ,  18   b ,  18   c  for securing the outrigger bar  15  into three desired positions, one stored vertical position and the two laterally extended positions. 
       FIGS. 3-4  show the outrigger bar  15  in a stored, vertical position with the release pedal  17  disposed in a notch  18   b  in order to lock the outrigger bar  15  into this stored position.  FIG. 5  depicts the outrigger bar  15  in a rotated lateral position with the release pedal  17  disposed in a notch  18   c  in order to lock the outrigger bar  15  into this laterally extended position on left side of the apparatus. 
     The outrigger support  14  may be manually or automatically actuated and controlled. In a particular embodiment, the outrigger bar  15  is raised and lowered manually from the stored, vertical position as illustrated in  FIGS. 3-4  to an extended lateral position by first depressing the release pedal  17 , releasing the outrigger locking mechanism  16 , and subsequently rotating the outrigger bar  15  into the lateral position on the selected side of the lift apparatus  1  as illustrated in  FIG. 5 . Once the outrigger bar  15  is in a laterally extended position on a selected side of the lift apparatus  1 , the outrigger locking mechanism  16  locks the bar  15  into the laterally extended position through the pedal&#39;s engagement with the notch  18   a ,  18   c  on the outrigger bar  15 . This secures the outrigger bar  15  into the laterally extended position and stabilizes the lift apparatus  1  while it is used to lift a person or object. 
     In an embodiment, the shape and length of the outrigger bar  15  may be fixed. In an alternate embodiment, the shape and length of the outrigger bar  15  may be modified to help stabilize the lift apparatus  1  and prevent it from tipping when it is used on an uneven surface. For example, the outrigger bar&#39;s length may be fixed or extendable using attachments in order to adjust its length and provide greater stabilization when the lift apparatus  1  is used to move a relatively heavy person or object. Also, spacers or attachments may be added to the end of the outrigger bar  15  in order to stabilize the apparatus when it is used on an uneven, stepped, or sloped surface. 
       FIGS. 1 and 6  illustrate a load support hanger  19  supported on the overhead support arm member  6  of the lift apparatus  1  according to an embodiment of the invention. In a particular embodiment, the hanger  19  is used to support a load, such as person or a heavy object. The hanger  19  may be fixed into a desired position on the overhead support arm member  6 . Alternatively, the hanger  19  may be slidable horizontally along the length of the overhead support arm member  6 . In a particular embodiment, the hanger&#39;s position along the overhead support arm member  6  is manually adjustable. However, the hanger&#39;s position may also be adjusted automatically using any suitable control system known in the art. The hanger  19  may also include an attachment device, such as a hook, carabiner, or any other known device in the art for securing a person or object to the overhead support arm member  6 . In a particular embodiment, the hanger  19  has a hook with a spring loaded locking mechanism for securing a sling to the overhead support arm member  6 . 
       FIG. 7  illustrates an exploded view of the overhead support arm  6 , selector collar  10 , lift rod  9 , rotatable head  20 , indexing detents  53  disposed on the rotatable head  20 , and selector collar switch activation element  29  for use with the apparatus shown in  FIG. 1  in accordance with an embodiment of the present invention. These features are discussed further, below. 
       FIGS. 8-14  illustrate close-up views of an exemplary selector collar  10  for use as a support arm selector with the lift apparatus  1 , according to an embodiment of the present invention. In an embodiment, the selector collar  10  has a hollow cylindrical body  50  that is sized to accommodate the lift rod  9  and rotatable head  20  through its body  50 , a curved slot  54  formed in the cylindrical body  50 , and a vertical selector collar locking mechanism (not shown) for securing the selector collar&#39;s vertical position along the rotatable head  20 . In an embodiment, the curved slot  54  may formed partially within an inner wall (not shown) of the selector collar such that the slot is not visible on the collar&#39;s outer surface. In another embodiment, the curved slot  54  may be formed through the wall of the cylindrical body  50  and visible, as illustrated in  FIGS. 7-17 . 
     In a particular embodiment, the selector collar  10  has at least two lateral extensions  51   a ,  51   b  and the vertical selector collar locking mechanism may have a combination of spring-loaded pins  52  disposed within each lateral extension  51   a ,  51   b  and indexing detents  53  disposed on the rotatable head  20 . The pins  52  engage with the indexing detents  53  to index vertical positions of the selector collar  10  along the rotatable head  20 . In a particular embodiment, the indexing detents  53  are sized to accommodate the spring-loaded pins and prevent the selector collar  10  from slipping down the rotatable head  20 . Also in a particular embodiment, there are two sets of indexing detents  53 , one disposed on each side of the rotatable head  20  (not shown). Each set of indexing detents  53  contains three indexing detents  53  disposed in a vertical relationship with respect to one another along the rotatable head  20  and aligns with one of the spring loaded pins  52  disposed in the selector collar&#39;s lateral extensions  51   a ,  51   b , respectively. 
       FIG. 10  illustrates a rear close-up view of the selector collar  10  for use with the lift apparatus  1 , according to one embodiment. In a particular embodiment, the selector collar  10  has two selector collar position sensor switches  28   a ,  28   b  disposed within it, which are positioned vertically with respect to one another along the rotatable head  20 . The selector collar position sensor switches  28   a ,  28   b  interact with a collar switch activation element  29  affixed to the rotatable head  20 . In a particular embodiment, when the selector collar  10  is in the uppermost position, the switch activation element  29  abuts and activates the lower selector collar position sensor switch  28   b  and when the selector collar  10  is in the lowermost position, the switch activation element  29  abuts and activates the upper selector collar position sensor switch  28   a . The lift mechanism  7  may only be activated when one selector collar position sensor switch  28   a ,  28   b  is activated, corresponding to the selector collar being located in the lowermost or uppermost position, as discussed below. 
       FIG. 11  illustrates a side close-up view of the selector collar  10  and the curved slot  54  and a lateral extension  51   b  formed within the hollow cylindrical body  50  of the selector collar  10  according to one embodiment.  FIG. 12  illustrates a top close-up view of the selector collar  10 , the curved slot  54  and the lateral extensions  51   a ,  51   b  formed within the hollow cylindrical body  50  of the selector collar  10  according to one embodiment.  FIG. 12  also depicts the spring-loaded pins  52   a ,  52   b  extending from outwardly the lateral extensions  51   a ,  51   b  and toward the central axis of the hollow cylindrical body  50  and the at least one selector collar position sensor switch  28   a ,  28   b.    
       FIG. 13  illustrates a front close-up view of the exemplary selector collar  10  of the apparatus shown in  FIG. 1  in a predetermined neutral position along the rotatable head  20  in accordance with an embodiment of the present invention. In this neutral position, neither selector collar position sensor switch  28   a ,  28   b  abuts the switch activation element  29 . In such an embodiment, an anchor bolt  27  fixed in lift rod  9  is located in the center of the curved slot  54 . Neither selector collar position sensor switch  28   a ,  28   b  is activated when the selector collar  10  is in this neutral position. In such an embodiment, the collar switch activation element  29  also prevents the collar from rotating to the selected side of the apparatus  1  when the selector collar is in the neutral position. 
       FIG. 14  illustrates a front close-up view of the exemplary selector collar  10  of the apparatus shown in  FIG. 1  in a predetermined uppermost position along the rotatable head  20  in accordance with an embodiment of the present invention. When the selector collar  10  is in this predetermined uppermost position, the selector collar switch activation element  29  abuts and activates the lowermost selector collar position sensor switch  28   b  illustrated in  FIG. 10 , and the overhead support arm member  6  is rotatable to a predetermined laterally extended position on a selected side of the lift apparatus  1 , corresponding to the uppermost collar position. 
       FIGS. 15-17  illustrate a method of rotating the overhead support arm member  6  to a selected side of the apparatus  1  shown in  FIG. 1  in accordance with an embodiment of the present invention.  FIGS. 15-16  illustrate how the overhead support arm member  6  may be moved to a selected side of the lift apparatus  1  when the selector collar  10  is moved to the uppermost position.  FIG. 16  illustrates the anchor bolt  27  fixed in lift rod  9  and abutting the side of the curved slot  54  thereby preventing further rotation of the selector collar  10 . In such an embodiment, the slot  54  shape and anchor bolt  27  limits the extent to which the overhead support arm  6  may be rotated to the selected side of the apparatus  1 . 
     Alternatively,  FIG. 17  illustrates how the overhead support arm member  6  is movable to the other selected side of the lift apparatus  1  when the selector collar  10  is moved to the lowermost position. In an optional embodiment, the overhead support arm member  6  may be detachably connected to the lift apparatus  1  in order to permit quick assembly and disassembly of the apparatus  1  and facilitate stowing the lift apparatus  1  in a small space, such as within an aircraft. 
       FIGS. 18-20  illustrate a control system  21  for controlling the lift mechanism&#39;s movement according to an embodiment of the invention.  FIG. 18  illustrates a schematic of an exemplary control system for use with an embodiment of the lift apparatus  1 . The control system may be manually or automatically actuated using any suitable control system known in the art, such as an electric or electronic control system, for example. In a particular embodiment, the control system  21  has a power switch  22 , a user controller  24 , at least one outrigger position sensor switch  25 , at least one locking mechanism position sensor switch  26 , and at least one selector collar position sensor switch  28 . The power switch  22  controls the power supplied to the lift mechanism  7 . The power source  23  may be an electrical outlet, a battery, a combination of these items, or any other suitable power source known in the art. In a particular embodiment, the power source  23  may be a rechargeable battery. The user controller  24  may be a hand held remote control device that interacts with the control system  21  through a wire or any suitable wireless connection known in the art. The user controller  24  may have power and lift control buttons. The power button turns the control system  21  on and off by activating and deactivating the power switch  22 . The lift control buttons control the vertical movement of the lift mechanism  7  when the control system is activated. The outrigger position sensor switch  25  and locking mechanism position sensor switch  26  communicate with the selector collar position sensor switch  28 . In a particular embodiment, the control system  21  activates the lift mechanism  7  only when the laterally rotatable outrigger bar  15  is rotated to a laterally extended position on a selected side of the lift apparatus  1 , the outrigger locking mechanism  16  locks the outrigger bar  15  into this laterally extended position, and the support arm selector, such as selector collar  10 , is in a predetermined vertical position corresponding to the selected side of the lift apparatus along the rotatable head  20  of the support arm, as described below. 
     In a particular embodiment, the control system  21  is configured to activate the lift mechanism  7  only when a set of switches associated with either one or the other side of the apparatus is closed and activated. 
     The at least one outrigger position sensor switch  25  and at least one locking mechanism position sensor switch  26  are operationally connected to and communicate with the at least one selector collar position sensor switch  28 . In a particular embodiment, the control system  21  has two sets of switches, each set corresponding to a selected side of the lift apparatus, such as the right or left side. In a particular embodiment, each set of switches has an outrigger position sensor switch  25 , a locking mechanism position sensor switch  26  and a selector collar position sensor switch  28 . For example, there may be one set of outrigger, locking mechanism, and selector collar position sensor switches associated with the right side of the apparatus  1  and another set associated with the left side of the apparatus  1 . In a particular embodiment, the lift mechanism  7  is activated only when all of the switches in one set of switches associated with a particular side of the apparatus is closed and activated. 
     In a preferred embodiment, the outrigger position sensor switches are activated when the outrigger bar  15  is moved into a predetermined laterally extended position on a selected side of the lift apparatus  1 . This activates the outrigger position sensor switch  25  associated with this selected side of the apparatus. When the outrigger locking mechanism  16  locks the outrigger bar  15  into this position, it activates the locking mechanism position sensor switch  26  also associated with this selected side of the apparatus  1 . 
     For example, in a particular embodiment, the outrigger position sensor switch  25  and locking mechanism position sensor switch  26  associated with the right side of the apparatus are activated only when the outrigger bar  15  is rotated and locked into position on the right side of the lift apparatus  1 . Conversely, the outrigger position sensor switch  25  and locking mechanism position sensor switch  26  associated with the left side of the apparatus are activated only when the outrigger bar  15  is rotated and locked into position on the left side of the lift apparatus  1 . 
     Also, in a particular embodiment the selector collar position sensor switches  28  are activated only when the selector collar  10  is moved into a predetermined, uppermost or lowermost, vertical position on the rotatable head  20 . In a particular embodiment, when the selector collar  10  is moved into the uppermost vertical position on the rotatable head  20 , as illustrated in  FIGS. 14-16 , the selector collar position sensor switch  28   b  associated with the right side of the apparatus  1  is closed and activated and the overhead support arm member  6  is limited by the collar  10  to be rotatable only to the right side of the apparatus  1 . Conversely, when the selector collar  10  is moved into the lowermost vertical position on the rotatable head  20 , as shown in  FIG. 17 , the selector collar position sensor switch  28   a  associated with the left side of the apparatus is closed and activated and the overhead support arm member  6  is limited by the collar  10  to be rotatable only to the left side of the apparatus  1 . 
     In a particular embodiment, when the outrigger bar  15  is rotated to the right side of the apparatus and the selector collar  10  is moved into an uppermost position on the rotatable head  20 , as illustrated in  FIGS. 15-16 , the switches associated with the right side of the apparatus are closed and activated. This permits the lift mechanism  7  to be actuated and the overhead support arm member  6  to be raised and lowered and to be rotated to the right side of the lift apparatus  1  only, as illustrated in  FIGS. 15-16 . Alternatively, when the outrigger bar  15  is rotated to the left side of the apparatus and the selector collar  10  is moved into an lowermost position on the rotatable head  20 , as illustrated in  FIG. 17 , the switches associated the left side of the apparatus are closed and activated. This permits the lift mechanism  7  to be actuated and the overhead support arm member  6  to be raised and lowered and to be rotated to the left side of the lift apparatus  1  only, as illustrated in  FIG. 17 . 
     In one embodiment, the control system  21  and the selector collar  10  design may desirably prevent the lift mechanism  7  from being actuated when the outrigger bar  15  and overhead support arm member  6  are rotated to opposite sides of the lift apparatus  1  with respect to one another. For example, in a particular embodiment, when the outrigger bar  15  is rotated to the right side of the apparatus  1  and the selector collar  10  is moved into the lowermost indexed position along the rotatable head  20 , which would permit the overhead member  6  of the support arm to be rotated to the opposite, or left side, of the apparatus  1 , the control system  21  would not be able to activate the lift mechanism  7  because the outrigger position sensor switch  25  and selector collar position sensor switch  28  associated with the right side of the apparatus  1  would be closed and open, respectively. The control system  21  and mechanical design of the selector collar collectively prevent the life mechanism from being actuated unless the outrigger bar  15  is locked into a position on a selected side of the apparatus and the overhead support arm member  6  is rotatable only to that same selected side of the apparatus to which the outrigger bar  15  extends. These configurations and safety features may desirably prevent the lift mechanism  7  from being actuated unless both the outrigger bar  15  and the overhead support arm member  6  are configured to be rotated to the same side of the apparatus in order to mitigate the risk of the apparatus tipping or otherwise becoming unbalanced while in use. 
       FIG. 19  illustrates a close-up view of the outrigger position sensor switch  25  of the control system  21  of  FIG. 18  according to an embodiment of the invention as well as a spring  34  connected to the outrigger support bar  15  and a base frame member  3 . 
       FIG. 20  illustrates a close-up view of the locking mechanism position sensor switch  26  of the control system  21  of  FIG. 18  according to an embodiment of the present invention.  FIG. 20  illustrates the locking mechanism  16  in a locked position and the locking mechanism position sensor switch  26  in a closed, activated state.  FIG. 20  further illustrates an outrigger position lobe  55  which is attached to the outrigger bar  15  and triggers the outrigger position sensor switch  25  shown in  FIG. 19  depending on the position of the outrigger bar  15 , according to a particular embodiment of the invention. 
     A method of using the lift apparatus  1  to move an immobile or semi-mobile person from a wheelchair or other assistive device, such as located in an airline terminal to a passenger seat on a vehicle such as an aircraft, and vice-versa, is described as follows in accordance with an embodiment of the present invention. 
     First, the lift apparatus is used to move the person from a wheelchair and into the apparatus  1 . The lift apparatus  1  may be positioned immediately beside and as close as possible to the wheelchair, for example, such as immediately beside the right side of the wheelchair. The person operating the lift apparatus  1  such as an airline employee may then lock the one or more wheels  4   a - 4   d  into place in order to prevent the lift apparatus  1  from sliding horizontally during use. The operator then presses the release pedal  17 , releases the outrigger locking mechanism  16 , and rotates the outrigger support bar  15  from the stored, vertical position to a laterally extended position on the left side of the apparatus  1 . Once the outrigger bar  15  is fully extended laterally the outrigger locking mechanism  16  locks the outrigger bar  15  into this left side laterally extended position. 
     A sling (not shown) is then placed around the person in the wheelchair. The apparatus operator then moves the selector collar  10  into a predetermined position on the rotatable head  20  corresponding to the left side of the lift apparatus  1 , for example in the lowermost position, and rotates the overhead support arm member  6  to the left side of the apparatus. The lift apparatus  1  operator then presses the power button on the user controller  24  in order to turn on the lift mechanism  7 . The lift operator then presses the lift control button in order to lower the overhead support arm member  6  down toward the person in the sling. The operator then connects the person to the lift apparatus  1  by attaching the sling to the hanger  19  on the overhead support arm member  6 . Next, the operator presses the lift control button on the user controller  24  in order to raise the lift mechanism  7  and elevate the person in the sling. Next, the operator rotates the overhead support arm member  6  to a central position directly over the lift apparatus  1  such as directly over the seat  41  in a particular embodiment. Then, optionally, the operator presses the lift control button on the user controller  24  in order to lower the sling and the person onto the lift apparatus  1 , and in a particular embodiment, onto the seat  41  in the lift apparatus  1 . The operator may then optionally move the selector collar  10  to the centre neutral position along the rotatable head  20 . The operator then returns the outrigger bar  15  from the laterally extended position to the stored vertical position by releasing the outrigger locking mechanism  16  (i.e. depressing the release pedal  17 ) and rotating the outrigger support bar  15  back into the stored, vertical position. 
     In a particular embodiment, the outrigger support bar  15  may be spring loaded using a spring  34  such that the outrigger support bar  15  rotates back into the stored, vertical position automatically when the operator presses the release pedal  17 , which automatically releases the locking mechanism. Next, the operator unlocks the wheels. Next, the operator may optionally disengage the wheel frame locking mechanisms  5 , such as if rotation of the lift apparatus  1  is required, and then pushes the lift apparatus  1  in order to transport the person. The optional wheel locking mechanisms may be any suitable wheel locking mechanisms known in the art, such as locking casters, for example, such as to prevent at least one of movement of the wheel around its horizontal axle, and/or swiveling or turning of the wheel around a vertical axis. 
     The lift apparatus  1  may optionally also be used with a portable ramp (not shown), which may be stowed below the apparatus  1  in order to facilitate transporting the apparatus  1  over an uneven or discontinuous surface on the airline terminal floor or for example, across a gap or angled surface between the aircraft entrance and the terminal or jetway floor. 
     Next, after the operator moves the lift apparatus  1  along the aisle in the vehicle such as an aircraft and prepares to unload the immobile person from the lift apparatus  1  and into the passenger&#39;s seat. First, the operator places the apparatus  1  immediately beside the immobile person&#39;s seat on the aircraft. Next, the operator may lock one or more of the wheels into place in order to stabilize the lift apparatus  1  and prevent it from sliding along the aisle in the aircraft. The operator then presses the release pedal  17 , releases the outrigger locking mechanism  16 , and rotates the outrigger support bar  15  from the stored, vertical position to a laterally extended position on the same side of the apparatus as the passenger&#39;s seat on the aircraft. In a particular embodiment, the locking mechanism may be spring-loaded such that by depressing the release pedal  17 , the bar  15  automatically and independently rotates back into the stored, vertical position. Once the outrigger bar  15  is fully extended, the outrigger locking mechanism  16  locks the bar  15  into the laterally extended position. Next, the operator moves the selector collar  10  into the predetermined position on the rotatable head  20  that would permit the overhead support arm member  6  to be rotated to the same side of the apparatus where the passenger&#39;s seat is located and the operator presses the power button in order to activate the lift mechanism  7 . The lift operator then presses the lift control button in order to lift the overhead support arm member  6 . The operator next rotates the overhead support arm member  6  over the seat on the aircraft such that the person in the sling is suspended directly over the passenger&#39;s seat. The operator next presses the lift control button on the user controller  24  in order to lower the overhead support arm member  6  and gently lower the person into the seat. The operator then removes the sling from the person&#39;s limbs. The operator may also remove the sling from the hanger  19  at this time. 
     After the operator helps the immobile person into his or her airline seat, the operator may then stow the apparatus on the aircraft or transport it back to the terminal by rotating the overhead support arm member  6  back to a central position, pressing the lift control button to lower the overhead support arm member  6  and hanger  19 , moving the selector collar  10  from the uppermost or lowermost position to a centered, neutral position and rotating the outrigger support bar  15  into the stored, vertical position, releasing the wheel locking mechanisms, and transporting the apparatus back to the airline terminal or stowing it in the aircraft for subsequent use at the passenger&#39;s destination. 
     According to a further embodiment, the lift apparatus  1  may have features that are modular, such as easily removable or re-fastenable structural components in order to facilitate quick disassembly and storage of the device, for example, into small spaces within an aircraft. For example, the overhead support arm member  6  may be optionally removable from the lift rod  9  and the hanger  19  may be optionally removable from the overhead support arm member  6 . 
     According to a further embodiment, the control system may include an emergency override switch for immediately shutting off the control system and stopping all actuation and lifting, for example, in the event of an emergency. 
     According to a further embodiment, the lift apparatus  1  may be self-propelled using any self-propulsion unit known in the art. The present invention may also be used to lift, transport, and transfer a person from a wheelchair to a seat in a vehicle, chair, bed, toilet seat and/or shower chair and vice versa in, for example, a home, nursing home, or hospital environment. 
     As will be apparent to those skilled in the art in light of the disclosure, many alterations and modifications are possible in the practice of this invention without departing from the spirit or scope of it. Accordingly, the scope of the invention is to be construed in accordance with the substance defined by the following claims. 
     LIST OF FEATURES 
     
         
           1  lift apparatus 
           2  base frame 
           3  base frame members 
           4  plurality of wheels 
           5  wheel frame locking mechanisms 
           6  overhead support arm 
           7  lift mechanism 
           8  cylindrical guide housing 
           9  lift rod 
           10  selector collar 
           11  handle bar 
           12  lift actuator 
           13  support bracket 
           14  outrigger support 
           15  outrigger bar 
           16  outrigger locking mechanism 
           17  release pedal 
           18  indexing notch 
           19  hanger 
           20  rotatable head on overhead support 
           21  control system 
           22  power switch 
           23  power source (i.e. battery) 
           24  user controller 
           25  outrigger position sensor switch 
           26  locking mechanism position sensor switch 
           27  anchor bolt 
           28  selector collar position sensor switch 
           29  collar switch activation element 
           30  emergency stop switch 
           31  piston rod 
           32  cylindrical housing 
           34  spring 
           41  seat 
           44  footrest 
           50  cylindrical body of selector collar 
           51  lateral extensions 
           52  spring loaded pins 
           53  indexing detents 
           54  curved slot 
           55  outrigger position lobe