Abstract:
A self-levelling lift system is provided, to transport payloads in dynamic settings. The lift comprises a superstructure, first and second support members, a carriage and a drive. The superstructure has rails along which the carriage moves. The support members allow for the superstructure to change angle in response to a changing relationship between a first surface and a second surface, such as the shore and a boat. Also provided is a use of the system for concurrently transporting a payload and allowing for pedestrian traffic.

Description:
CROSS-REFERENCES TO OTHER APPLICATIONS 
       [0001]    This application claims the benefit of U.S. provisional application 60/853,323 filed Sep. 15, 2006, the disclosure of which is incorporated herein by reference. 
     
     FIELD OF THE INVENTION 
       [0002]    The present disclosure relates to a self-levelling lift system for use in settings where the slope of the supporting structures undergoes change over time. More specifically, it relates to an overhead, mechanized gangway lift system for wheelchairs. 
       BACKGROUND 
       [0003]    In recent years there has been the development of sporting equipment for the disabled, including modifications to existing sports equipment. This has allowed many people to participate in sports that they could previously not consider because of handicaps including paraplegia and quadriplegia. At the same time, advancements have been made in mobility aids, including, for example, lifts for use in the home, and for buses. 
         [0004]    For example, US patent application publication number 20060117984 discloses a stair-case lift for transporting a disabled person between floors. It includes at least one guide rail extending substantially parallel to a stairway, a moveable carrier frame suspended from the guide rail means including carrier support means, and drive means of a rack and pinion type drive for displacement of the carrier frame along the guide rail. 
         [0005]    Similarly, U.S. Pat. No. 5,269,227 discloses a portable system for aiding persons in ascending or descending stairways that comprises either a motorized portable upper body support assembly or a motorized vehicle for detachably drivingly engaging elongate tracks associated with different stairways. The detachability of the motorized unit from the track, combined with its portability, enables the user to employ the same portable unit interchangeably with any stairway in any location so long as the stairway is equipped with a mating track, thereby enabling an unlimited number of stairways in private or public buildings to be adapted inexpensively for use by physically impaired persons. The portable motorized unit is readily able to adapt to stairways of different slopes and configurations, and to tracks on either the right-hand or left-hand side of the stairway, so as to maximize the versatility of the portable unit for use with virtually any track-equipped stairway. 
         [0006]    A monorail access system is disclosed in U.S. Pat. No. 5,709,154. This monorail access system makes a boat handicapped accessible. More specifically, a battery powered chair assembly is suspended from an overhead monorail track system, whereby by activating a control mechanism an individual may move anywhere in the boat where the track is installed. Once an individual is seated in the chair assembly, the monorail system allows the individual to travel to the cabins, flying bridge, downstairs to the galley, outside to the rear deck for sunbathing or fishing or over the side to a dock. 
         [0007]    While the foregoing allow increased mobility for physically handicapped people, they are only useful in static settings. In other words, a track or railing must be in place and a moveable assembly mounted on the track. Unfortunately, such systems are not useful for dynamic settings, such as, for example, gangways onto boats, wharves and planes. Of these, gangways onto wharves provide the greatest challenge as the level of the gangway is dependent upon the water level, which in an ocean environment, is constantly changing. Gangways have been developed to accommodate changing water levels. 
         [0008]    For example, U.S. Pat. No. 5,950,267 discloses a portable gangway with levelling stairs. It includes first and second longitudinal frame members each having an elongate housing with a wall structure surrounding an interior thereof and a pair of longitudinal elongate rails extending through a length of the housing in parallel relation to each other and terminating at opposite distal ends; the pair of rails including a fixed rail and a moving rail. A series of step members, each including top bottom step surfaces, are rotatably supported between the first and second longitudinal frame members in pivotal interconnection with the pair of rails of each frame member. Mounting platforms attach to the distal ends of the rails and enable one end of the gangway to move through an arc of movement relative to an opposite fixedly mounted end, thereby causing movement of the moving rails relative to the fixed rails, within each frame member, resulting in synchronized rotation of the step members so that the top and bottom step surfaces of the step members remain horizontal and level upon a change in an upward or downward angle of the gangway. Handrails are removably attachable to the gangway along the outboard sides of the longitudinal frame member and include articulating joints to permit angular movement of the handrails with the gangway. 
         [0009]    U.S. Pat. No. 5,657,832 discloses a stairway for connecting a floating dock or boat to a stationary dock or land. The stairway moves with the moving member and includes stringers connected to the hand rails by pickets and step supporting pivot arms connected to adjustment arms to form a compound parallelogram linkage in which the picket members and the pivot arms remain vertical during movement of the stairway whereby the steps remain horizontal and the hand rails remain parallel to the stringer members during such movement. Similarly, U.S. Pat. No. 4,333,196 discloses a gangway that is has steps that remain horizontal whatever the inclination of the gangway. This is accomplished by using longitudinal side-members and a girder that form a parallelogram articulated about four horizontal axles, two of which are pivotally mounted on the structure supporting the stairway. Thus,an articulated parallelogram is produced. While the foregoing gangways allow for changing levels, they are often far too steep for wheelchairs. 
         [0010]    Most gangways far exceed the maximum 1:12 (40) pitch recommended by the  Americans with Disabilities Act Accessibility Guidelines  (ADAAG) of the U.S. Architectural and Transportation Barriers Compliance Board (ATBCB), even at high tide. Because of the changing ocean tides, some gangways can range in pitch from 1° to 45° making it impossible for some people to independently access the wharf. ADAAG regulation 4.8.2 requires that the maximum rise for any run in a ramp be no greater than 30°. By default this precludes all conventional marina gangways from use by wheelchair-bound patrons. 
         [0011]    One system, Ramp Rider™ utilizes gangway technology and rail technology to arrive at a system for wheelchairs to be transported between land and a boat or float. The wheelchair is carried in a car that has four tires (two in the front and two in the back) for running on two rails that form the base of a parallelogram. The relationship between the front and back wheels and the rails ensures that the car remains horizontal. It is a stand- alone system and cannot be integrated into an existing gangway. This requires that two gangways and two access points be available in order to move both wheelchairs and foot traffic. 
         [0012]    One cannot simply combine existing wheelchair lift systems that are suitable for static settings with existing gangway designs that are suitable for dynamic settings and arrive at a system that will allow safe access to, for example, boats, floats and planes, while still permitting regular foot traffic. It is an object to overcome the deficiencies in the prior art. 
       SUMMARY OF THE INVENTION 
       [0013]    The present embodiment provides a self-levelling lift for transporting payloads in dynamic settings, in other words, where the slope of the supporting structures are required to undergo change. If a gangway is in place, the system can rely on the existing support and anchor members, assuming that they are capable of supporting the increased weight. By suspending the travelling car over an existing gangway, the required space at the foreshore and landing float is virtually zero. Further, regular foot traffic on the gangway is not impeded by the system. Additionally, the car can be folded out of the way of the gangway, when not in use. 
         [0014]    More specifically, what is provided is a self-levelling lift system, to transport payloads in dynamic settings. The lift comprises: a superstructure having a first end, a second end and a mount extending between the first end and the second end; first and second support members located proximal to the first end and the second end of the superstructure, wherein the first support members are in moveable contact at a distal end with a first surface, and the second members are affixed at a distal end to a second surface and are in pivotal engagement with a second surface at a distal end; a carriage in moveable engagement with the mount; and a drive to move the car between the first and the second end. 
         [0015]    In one aspect the mount comprises two rails. 
         [0016]    In another aspect the carriage comprises a car, a framework, and a transporter, wherein the transporter has wheels for engaging the rails of the mount. 
         [0017]    In another aspect the carriage further comprises a hydraulic ram mounted between the framework and the transporter, to assist in maintaining the car level. 
         [0018]    In another aspect the car is comprised of two doors, two sides, hinges and a platform, the doors rotatably attached to the platform by the hinges. 
         [0019]    In another aspect the drive is a cable drive. 
         [0020]    In another aspect the cable drive comprises a motor, a worm gear, a winch and a cable. 
         [0021]    In another aspect the system further comprises a brake. 
         [0022]    In another aspect the motor, worm gear and winch are mounted on the transporter. 
         [0023]    In another aspect the system further comprises controls in electronic communication with the cable drive and located within the car. 
         [0024]    In another aspect the system further comprises door hydraulic rams to assist in opening and closing the doors. 
         [0025]    In another aspect the system further comprises retractor hydraulic rams to assist in folding of the car. 
         [0026]    In another aspect the framework further comprises a telescoping arm for raising and lowering the car. 
         [0027]    In another aspect, the superstructure defines an A-frame comprising two rails that function additionally as girders and trusses extending there between. 
         [0028]    In another aspect the system further comprises a gangway located below the superstructure. 
         [0029]    In another aspect, the mount comprises two rails; the carriage comprises a framework, a transporter, wherein the transporter has wheels for engaging the rails and a car, wherein the car is comprised of two doors, two sides, hinges and a platform, the doors rotatably attached to the platform by the hinges; and the drive is a cable drive. 
         [0030]    In another aspect the system further comprises an anchor block. 
         [0031]    Also provided is a use of a system comprising:
       a superstructure comprising a first end, a second end and two rails extending between the first end and the second end;   first and second support members located proximal to the first end and the second end of the superstructure, wherein the first support members are in moveable contact at a distal end with a first surface, and the second members are affixed at a distal end to a second surface and are in pivotal engagement with a second surface at a distal end;   a carriage in moveable engagement with the mount, the carriage comprising a car, a framework, and a transporter, wherein the transporter has wheels for engaging the rails; and   a drive to move the car between the first and the second end, to transport a payload between a static surface and a non-static surface.       
 
         [0036]    In one aspect of the use of the system, the car is retracted and folded. 
         [0037]    Also provided is a use of a system, the system comprising:
       a superstructure comprising a first end, a second end and two rails extending between the first end and the second end; first and second support members located proximal to the first end and the second end of the superstructure, wherein the first support members are in moveable contact at a distal end with a first surface, and the second members are affixed at a distal end to a second surface and are in pivotal engagement with a second surface at a distal end;   a carriage in moveable engagement with the mount, the carriage comprising a car, a framework, and a transporter, wherein the transporter has wheels for engaging the rails;   a drive to move the car between the first and the second end; and   a gangway below the superstructure, to concurrently transport a payload in the car and allow pedestrian traffic on the gangway.       
 
         [0042]    In another aspect, said use is remotely controlled by an operator. 
         [0043]    In another aspect the payload is cargo. 
         [0044]    In one aspect of the use of the system the car is retracted and folded. 
     
     
       FIGURES 
         [0045]      FIG. 1  is a perspective view of an overhead self-levelling lift system in accordance with an embodiment. 
           [0046]      FIG. 2  is a perspective view showing the superstructure and supporting framework of the overhead self-levelling system of  FIG. 1 . 
           [0047]      FIG. 3  is a perspective view showing the carriage on the superstructure of the overhead self-levelling system of  FIG. 1 . 
           [0048]      FIG. 4  is an exploded perspective view of the carriage of  FIG. 3 . 
           [0049]      FIG. 5  is a perspective view showing the cable drive of the overhead self-levelling system of  FIG. 1 . 
           [0050]      FIG. 6  is a perspective view of an overhead self-levelling lift system mounted overtop of a gangway in accordance with an embodiment. 
           [0051]      FIG. 7  is a perspective view showing the carriage of  FIG. 3  in the partially folded position. 
       
    
    
     DESCRIPTION 
       [0052]    An overhead self-levelling lift system, generally referred to as  10  is shown in  FIG. 1 . The lift system  10  has a superstructure, generally referred to as  12 , as shown in  FIG. 2 . The superstructure  12  has two girders  14  extending along the length of the superstructure and trusses  16  therebetween to form an A-frame-type structure. In one embodiment, the girders  14  functional so as rails  18 . Alternatively, the superstructure supports two rails  18  that are affixed to the girders  14  and extend the length of the superstructure  12 . The rails  18  function as mounts. 
         [0053]    The superstructure is pivotally mounted proximate to a first end  20  and a second end  22  to a first and second supporting frame work  24 ,  26 , each of which has two support members  28 ,  30 , respectively and a header  32 . Each support member  28  of the first supporting framework  24  is terminated with a roller  34  at a distal end  36  relative to the header  32 . Each support member  30  of the second supporting framework  26  is terminated with a pivot mount  38  at or near a proximal end  40  relative to the header  32 , for pivotal engagement with the girders  14 . The distal end  42  of each support member  30  is affixed to an anchor block  44  by a bottom flange plate  46 . The anchor block  44  is suitably affixed to the shore and is also the attachment point for a gangway  48 . The gangway can be any design of gangway, as the overhead self-levelling lift system  10  can be manufactured to the appropriate dimensions. 
         [0054]    A carriage, generally referred to as  50  is rollably suspended from the rails  18  as shown in  FIG. 3 . The carriage  50 , as shown in  FIG. 4  has car  52  and a framework  54  that connects the car  52  to a transporter  56 , which is located above the car  52 . The car  52  has a platform  58 , a proximate side  60 , an opposing side  62 , a back door  64  and a front door  66 . The proximate side  60  assists in supporting the remainder of the car  52  and is telescopically attached to the framework  54  by a telescoping arm  68 , which forms part of the framework  54 . The telescoping arm  68  allows the car  52  to be raised and lowered. 
         [0055]    The opposing side  62  consists of two safety rails that are pivotally mounted on the proximate side  60 . The doors  64 ,  66  are pivotally mounted on the platform  58  by hinges  63 . The doors  64 ,  66  function as a ramp when in the open position. Two door hydraulic rams  70  are located between the platform  58  and the back and front doors  64 ,  66 , respectively, to assist in opening and closing the doors  64 ,  66 . Two retractor hydraulic rams  72  are located between the platform  58  and the framework  54  to assist in folding the car  52  by raising the platform  58  into a vertical position. A fifth hydraulic ram  74  is located between the framework  54  and the transporter  56 , and aids in maintaining the platform  54  level. The transporter  56  has trucks  76  mounted on the undersides  78  of the transporter  56  such that the wheels  8 o of the trucks  76  rollably suspend the carriage  50  from the rails  18 . The transporter  56  additionally has Teflon sides  57 . 
         [0056]    A cable drive, generally referred to  82 , as shown in  FIG. 5  is connected to the carriage  50 . The cable drive  82  has a cable  84 , a winch  86 , a motor  88  and a worm drive go. Additionally, a brake  92  is integrated into the cable drive  82 . Controls  94  are in electronic communication with the brake  92  and the cable drive  82  and are housed within the carriage  50 , more specifically in the transporter  56 , as shown in  FIG. 4 . A pan  59  covers the cable drive  82 . The worm drive go transfers power from the motor  88  to the winch  86  and the winch  86  advances the cable  84  to move the carriage  50  along the rails  18 . The direction that the cable  8 o moves determines the direction that the carriage  50  moves. 
         [0057]    In use, the overhead self-levelling lift system  10  can transport cargo, people in wheelchairs, powerchairs and scooters, able-bodied people and essentially any payload that weighs less than about 3000 pounds, in dynamic settings, such between a static surface, for example a runway, or the shore and a non-static surface for example a plane deck, a float deck or a ship. At the first end  20  the appropriate door  64  or  66  is opened, and the payload is loaded. As mentioned above, the door  64  or  66  becomes a ramp in the open position, to allow wheelchairs for example, to roll onto the platform  58 . The door  64  or  66  is closed, the brake  92  is released and the cable drive  82  is actuated to move the carriage  50  along the rails  18 . Once the carriage  50  reaches the second end  22 , the brake  92  is engaged, the appropriate door  64  or  66  is opened, again becoming a ramp, and the payload is unloaded. When used in conjunction with a gangway  48 , as shown in  FIG. 6 , the overhead self-levelling lift system  10  can concurrently move pedestrian traffic along the gangway  48  and a payload in the car  52 . 
         [0058]    The car  52  can be folded away when not in use. As shown in  FIG. 7 , the opposing side  62  is pivoted upward, the front and back doors  64 ,  66  are opened, the platform  58  and the front and back doors  64 , 66  are raised into the vertical position with the assistance of the retractor hydraulic rams  72  and the car  52  is raised by retracting the telescoping arm  68 . 
         [0059]    The foregoing is a description of an embodiment of the invention. As would be known to one skilled in the art, variations in the design that do not alter the scope of the invention are contemplated. For example, one rail could be used rather than two, and a cable system that is suspended by pulleys could replace the rail system. The girders and trusses could be replaced by any supporting superstructure, including joists and rafters, for example. The rollers terminating the columns of the first supporting framework could be replaced with a single roller or with any means to permit horizontal movement between the column and the float, for example, but not limited to, a slide mechanism. Similarly, the columns can be affixed to an existing gangway and utilize the system that allows the gangway to move across the float. The anchor block could be, for example, but not limited to a steel framework, or a concrete block. The cable drive can be replaced with any drive as would be known to one skilled in the art, including for example, but not limited to a chain drive or a belt drive. Similarly the wheels of the trucks can replaced with belts that move along cogs. The controls can be located on the gangway as an alternative to having them in the carriage, or can be both in the carriage and at each end of the gangway, for example. This would permit remote operation of the system by an operator. The car can be, for example, but not limited to, a platform, a box, or a specialized structure for carrying cargo.