Abstract:
A method and apparatus is described as having the useful purpose of assisting ambulatory infirm individuals to their feet from a floor level posture when non-injurious falls are experienced. A mast guided seat that is translated along the mast by a D.C. motor driven linear actuator is supported on a wheeled frame for convenient movement by a care-giving party to proximity with a downed individual. The seat is capable of a floor contacting position. As the seat approaches the floor, a wheel breaking mechanism is engaged to prevent further movement of the machine along the floor as the user mounts the seat.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
       [0001]     Not Applicable  
       STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT  
       [0002]     Not Applicable  
       BACKGROUND OF THE INVENTION  
       [0003]     1.Field of the Invention  
         [0004]     This invention includes a machine and method for aiding caregivers of the ambulatory infirm. In particular, the invention comprises a device and procedures for assisting a person that is capable of self-support and limited mobility but incapable of rising from a floor surface to a standing position.  
         [0005]     2. Description of Related Art  
         [0006]     The prior art is replete with hoists for lifting and transporting invalids. The disclosures of U.S. Pat. No. 6,430,761 to Alexander Brandorff et al; U.S. Pat. No. 6,367,103 to Nicholas Collins; U.S. Pat. No. 6,289,534 to Reza Hakamiun et al; U.S. Pat. No. 5,802,633 to Guido Capaldi; and U.S. Pat. No. 4,633,538 to David R. James et al are representative. Of predominate concern to this prior art has been provision of a device to remove an invalid from a bed or transfer an invalid from a wheel chair to a bed.  
         [0007]     While there is a great need for machines to assist the invalid and incapacitated, the prior art has not adequately addressed the needs of the ambulatory infirm. The ambulatory infirm are those individuals having impaired mobility due to age or injury but are nevertheless able to stand erect and walk. Often, however, the mobility impediments of such individuals also preclude an ability to raise oneself from a floor surface to the erect position. In the normal course of movement, such individuals rise to standing from an intermediate platform such as a chair or bedside. From an intermediate platform, the individual may shift their primary body weight from the intermediate platform surface directly onto their legs and feet. When rising from a floor surface, however, other muscle and skeletal systems must be used to achieve the erect posture.  
         [0008]     An unimpaired person will usually regain erect posture from the prone position by first rising to a kneeling position. This places much of the body weight directly on one or both knees. Unfortunately, due to arthritis or injury, any weight or pressure on the knees of many individuals among the ambulatory infirm is extremely painful. The most the care-receiver can achieve for themselves or with immediately present assistance, is a sitting position with a generally erect torso and buttocks on the floor surface.  
         [0009]     The circumstance giving rise to a need for the present invention that is most familiar to our society includes the presence of a care-giving assistant such as a spouse, nurse or personal assistant. In the case of a care-giving spouse, the care-giver may be as incapacitated as the care-receiver i.e. one ambulatory infirm individual is aiding another ambulatory infirm individual. Specifically, the strength to lift a care-receiver directly from a floor surface to their feet is often beyond the care-giver&#39;s capacity. Hence, when the care-receiver falls or is unseated in some manner, third party assistance must be called to restore the fallen to their feet.  
         [0010]     It is an objective of the present invention, therefore, to provide the ambulatory infirm a device that will assist them to regain their feet from a sitting position on a floor surface.  
         [0011]     Another object of the present invention is a personal lifting device that is sufficiently light, mobile and may be manipulated by another ambulatory infirm individual.  
       BRIEF SUMMARY OF THE INVENTION  
       [0012]     These and other objects of the invention as will become apparent from the detailed description to follow are served by a personal assistance apparatus supported from a wheeled, H-shape base frame. The assistance apparatus comprises a mast having its axis set at a small angle, 5° from vertical, for example, to confine translation of a bucket type seat in both directions along the mast axis. In the presently preferred embodiment, seat translation along the mast is driven by a parallel axis linear actuator that is energized by an electric motor. Elements are aligned to allow the seat to be driven down the mast to floor contact. As the seat approaches floor contact, a follower mechanism activates a braking mechanism to immobilize the apparatus support wheels. Such immobilization of the support wheels provides resistance to external forces imposed by an infirm users efforts to enter the seat.  
         [0013]     Low sidewalls and padded arm rests on the lift apparatus seat provide the infirm user a convenient support and fulcrum to position their posterior into the seat confines. More importantly, the arms provide important test obstacles to a residual ability to stand or walk. A person that cannot manipulate themselves onto the floor-level seat surface between the lateral arm barriers, probably cannot or should not be attempting to stand or walk. The very reason for the fall, or as a consequence of the fall, may be a structural failure in the body of the fallen person. Any forced attempt to return the fallen person to their feet could seriously exacerbate the original injury.  
         [0014]     A battery powered motor that is controlled by a console or switch module that is accessible to the infirm user gives the user an option to personally control the rate the seat rises and lifts the user. 
     
    
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS  
       [0015]     The invention is hereafter described in detail and with reference to the drawings wherein like reference characters designate like or similar elements throughout the several figures and views that collectively comprise the drawings. Respective to each drawing figure:  
         [0016]      FIG. 1  is a pictorial view of the invention;  
         [0017]      FIG. 2  is a side elevation view of the invention with the seat at a floor engagement position;  
         [0018]      FIG. 3  is a backside elevation view of the invention with the seat at a floor engagement position;  
         [0019]      FIG. 4  is a plan view of the invention;  
         [0020]      FIG. 5  is a sectioned elevation view of the invention;  
         [0021]      FIG. 6  is a side elevation view of the invention with the seat at a raised position;  
         [0022]      FIG. 7  is a backside elevation view of the invention with the seat at a raised position; and,  
         [0023]      FIG. 8  is a schematic of the braking mechanism.  
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0024]     Referring to  FIGS. 1 through 4 , a presently preferred embodiment of the invention comprises a substantially H-shaped base frame  10  supported by four wheels  12 ,  13 ,  14  and  15 . The front wheels  12  and  13  may have a fixed rotational plane whereas the rear wheels  14  and  15  are preferably castered about a substantially vertical axis.  
         [0025]     A mast assembly  20 , shown in sectioned elevation by  FIG. 5 , comprises a fixed column  22  of square or rectangular steel tubing stock that is secured at its lower end by welding and/or bolted flanges  24  to the cross member  17  of the base frame  10 . This fixed column  22  serves as a guide and support track for the seat assembly  30 . The longitudinal axis of column  22  is preferably set at a convenient angle, 5° for example, to the vertical plane  28 . Such inclination of the column axis  26  increases the apparatus stability as the loaded seat  36  is raised. As the seat load rises along the column  22 , the seat load center translates toward the apparatus center of gravity. Additionally, sliding friction between the fixed column  22  and the seat carrier sleeve  32  is minimized by a correspondingly minimal deflection of the column.  
         [0026]     The seat carrier sleeve  32  is preferably configured for a close sliding fit over the fixed column  22  for telescoped translation along the fixed column length. Secured to the seat carrier sleeve  32  is a seat mounting bracket  34 . The seat mounting bracket  34  provides a direct attachment interface for the seat structure  36 .  
         [0027]     Seat translation force is applied by a linear actuator assembly  40 . In a presently preferred embodiment of the invention, the actuator assembly  40  comprises a threaded drive shaft  42  that is rotationally powered by a D.C. electric motor  43  via a belt or chain driven transmission  44 . The rotating drive shaft is preferably confined within a shaft housing  46 . Those of ordinary skill in the art will recognize the obvious alternative utility of a direct gear drive or worm drive transmission between the motor  43  and the drive shaft  42 .  
         [0028]     Telescoping within the shaft housing  46  is an actuator tube  45  having a cooperatively threaded chase ring  47  meshed with the shaft  42  threads. An upper end of the actuator tube  45  is secured by means of a clevis pin  49 , for example, to a load bracket  50 . The load bracket  50  is an integral projection from the seat carrier sleeve  32  and thereby serves as a force application point on the carrier sleeve  32 . As the actuator tube  45  is axially translated along the drive shaft  42  by motor driven rotation of the drive shaft, the carrier sleeve  32  and seat  36  are translated correspondingly.  
         [0029]     Although hydraulic or chain mechanisms may be used for translating the seat assembly  30 , a screw driven linear actuator is preferred due to inherent safety. A selected screw pitch will prevent the possibility of a “free fall” of the seat assembly in the event of a power failure.  
         [0030]     Also secured to the drive shaft housing  46  is a handlebar manual control  52  for convenient control and rolling transport of the apparatus over a substantially flat floor surface.  
         [0031]     Primary energy for the low voltage (12v) D,C, motor  43  may be derived from a battery pack  70  secured to the base frame  10 . A charger and controller unit  72  may be secured to the opposite side of the base frame  10 . A tethered control console  74  may provide a direct interface between the invention power features and the operator who may be either a care-giver or a care-receiver.  
         [0032]     As the descending seat  36  approaches the supporting floor surface, a wheel braking system  60  is engaged to prevent the unit from moving due to the care-receiver&#39;s manipulations into the seat. A simple but effective brake assembly  60  is represented by the schematic of  FIG. 8  which comprises a friction shoe  61  respective to each front wheel  13  and  14 . The schematic of  FIG. 8  illustrates only wheel  13  but the elements shown are to be understood as duplicated on the opposite side of the apparatus respective to wheel  12 .  
         [0033]     The friction shoes  64  are secured to respective shoe carriers  54 . The shoe carriers are pivotally secured at  55  to the frame  10 . Also pivotally connected to each shoe carrier  54  is one end of a link rod  62 . The opposite end of each link rod is pivotally secured to the driven arm of a bell crank  63 . The bell crank  63  is pivotally secured at  56  to a frame element  10 .  
         [0034]     The driving arm of each bell crank  63  is pivotally attached to opposite ends of the same transverse load bar  64 . A pair of transversely spaced load rods  65  are secured to a lower load bar  64  and extend upwardly through aligned apertures in the base cross member  17 . The penetration of the cross member  17  by the load rods  65  is axially unrestrained.  
         [0035]     Above the cross member  17 , the load rods  65  are structurally connected by an upper load bar  67 . Threaded assembly components  68  above and below the upper load bar  67  provide means to adjust the special separation between the upper face of the cross member  17  and the lower face of the upper load bar  67 .  
         [0036]     Upward penetration of the load rods  65  through the cross member  17  is limited by a thread abutment (not shown) on the load rods  65 . Axial displacement of the load rods is biased against the threaded abutment by coiled springs  66 . The threaded abutment is adjusted to set an optimum position of shoe  61  disengagement from the surface of wheels  12  and  13 . Such shoe disengagement is resiliently sustained by the bias of springs  66 .  
         [0037]     The schematic of  FIG. 8  illustrates the break assembly  60  at the shoe engaged position where the wheels  12  and  3  are restrained from rotating. This engaged position is imposed by the lower edge  33  of the seat carrier sleeve  32  as it bears against the upper load bar  64  when the descending seat  30  approaches floor level.  
         [0038]     At the point that the shoes  61  are firmly set against the wheels  12  and  13 , the upper load bar  67  passes the abutment edge  82  of a break retainer assembly  80 . The break retainer assembly comprises a bell crank pivoted strap  84  that may be pivotally anchored about the axis  86 . The vertical leg  88  of the bell crank is terminated by a hook feature  81 . A horizontal leg  89  of the assembly  80  is a break release tab.  
         [0039]     A retaining rod  90  secured to the frame cross member  17  freely penetrates an aperture in the vertical leg  88 . A threaded abutment  92  sets an angular limit position of the vertical leg  88  about the axis  86 . A coiled compression spring  94  between the vertical leg  88  surface and a rod terminus  95  exerts a standing rotational bias on the assembly  80  toward the abutment  92 . As the upper load bar  67  is displaced by a descending seat carrier sleeve  32 , the outer edge of the upper load bar  67  engages the sloped face of the bell crank hook feature  81  on the break retainer assembly. This engagement rotates the bell crank  84  about the axis  86  against the bias of spring  94  until the upper face of the load bar  67  passes below the hook abutment edge  82 . At this point, the spring  94  bias restores the bell crank against the abutment  92  and latches the load bar  67  at the brake engaged position.  
         [0040]     The brake engagement is maintained by the brake retainer assembly  80  after the edge  33  of the seat carrier sleeve  32  is raised above and off the upper load bar  67 . Brake release is obtained by manually applied force on the release tab  89  which rotates the bell crank  84  against the bias of spring  94  and displaces the hook abutment  82  from the operating plane of load bar  67 . With the hook abutment removed, the bias of break release spring  66  pulls the break shoes  61  from engagement with the wheels  12  and  13 .  
         [0041]     Having described the mechanical elements and assembly of the invention, the following example may represent a typical procedure of the invention in use. In the frequent case of an elderly couple, one is unseated or falls to the floor. Although the fallen one is capable of walking, he or she is incapable of regaining their feet from the floor. Correspondingly, the mobile spouse is physically incapable of assisting the fallen spouse to their feet.  
         [0042]     Responsive to the predicament, the mobile spouse seeks out the present invention and by the handle bars  52 , pushes the machine to the fallen spouse. On this score, It should be recognized that the present apparatus may be constructed to dimensions compatible with passing through interior portals. A machine having the capacity to lift a seat load of 350 pounds may be constructed to weigh less than 100 pounds. Hence, little physical effort is required to roll the machine: an essential characteristic for a machine to be used by a spousal pair of ambulatory infirm individuals.  
         [0043]     With the fallen spouse sitting erect, buttocks on the floor, the machine is aligned closely behind the fallen spous and the seat  36  lowered to the floor by the tethered control console  74 . As the seat  36  approaches floor contact, the brake assembly  60  engages the wheels  12  and  13  to firmly secure the machine position on the floor.  
         [0044]     The fallen spouse next manipulates him or herself into the seat  36  using their arms and elbows on the padded arms  38  of the seat. The ability and capacity of the fallen spouse to manipulate themselves into the seat is a strong indication of their ability to maintain their feet and walk after their fall. A critical bone fracture injury, for example, will become painfully apparent from such manipulations. Although the invention seat  36  could be constructed without the arms  38  to allow a person to roll or be rolled onto the seat, it is possible that by doing so, any injuries that caused or arose from the fall may be exacerbated by an attempt to stand. Hence, the seat arms  38  offer test obstacles to the wisdom of attempting to stand after a fall.  
         [0045]     Once the fallen spouse has managed to position themselves on the seat  36  they may, at this point, take possession of the control console  74  and command the motor  43  to drive the actuator assembly  40  along the seat lifting direction. When the seat  36  has risen to a comfortable level and the fallen spouse has assessed their physical condition, they may exit the seat by shifting their body weight to their feet in a normal motion.  
         [0046]     A point has been made of the importance that the seat arms  38  may have upon the safe usage of the invention. Recognition of this safety characteristic does not preclude constructions of the invention without such seat arms or with selectively removed arms.  
         [0047]     Non-illustrated embodiments of the invention having no arms or removable arms for the load platform (seat)  30  may be given household and light industrial uses and utilities beyond lifting duties for the ambulatory infirm. One example of such household utility may be as a powered step platform for reaching high shelves and cabinets. An example of light industrial use may be the placement and removal of 100+ pound stock in a lathe. Both examples may require a load platform that is positioned substantially level with the supporting floor surface but is also immobilized along that floor surface when load is deposited on or discharged from the platform.  
         [0048]     While preferred embodiments of the invention have been shown and described, modifications thereof may be made by those skilled in the art without departing from the spirit or teaching of the invention. The embodiments described herein are exemplary only and are not intended as limiting or exclusive. Many variations and modification of the invention are possible and obvious to those of ordinary skill in the art. Accordingly, the scope of protection is not limited to the embodiments described herein, but is limited only by the following claims, the scope of which shall include all equivalents of the subject matter of the claims.