Abstract:
A patient self-assist transfer aid provides an open box frame having a base for fitting beneath a mattress of a bed, a riser section extending upwardly from the base for extending around an edge of the mattress and a positioning section for extending out over the mattress from the riser section. The open box frame may be positioned around the mattress end at the foot of the bed to leave the major sides of the bed open for ease of access. A linkage is fitted to the positioning section of the open box frame and may be extended therefrom to position a handle within easy grasp of a person laying in the bed. A spring system urges the linkage outwardly, but is balanced by a motor and pulley system. A handle is pivotally attached to the linkage and for grasping by a patient recumbent in the bed for raising himself with motor assistance or for lowering himself into bed.

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     This application is related to and a continuation in part of application Ser. No. 09/517,730 filed Mar. 2, 2000, now U.S. Pat. No. 6,425,154. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to apparata for use around a bed for aiding a person in moving himself from a fully reclined position on the bed to a standing position adjacent the bed and back. 
     2. Description of the Art and Problem 
     Numerous systems for helping patients get into and out of bed without caregiver assistance exist. Many of the references teach bed rail and handle systems, adapted by positioning and shaping, to give support to a person moving from a sitting position on a bed to a standing position adjacent the bed, or from a standing position back to a sitting position. Indeed, for many infirm individuals, moving from a sitting to a standing position is the greatest challenge and such devices are very useful for maintaining balance as they stand. However, the problems involved in getting into and out of bed frequently involve more than moving from standing to sitting or from sitting to standing. Some references implicitly recognize that helping the patient stand up from, or sit down on, a bed or chair is just one part of the problem, for example U.S. Pat. No. 3,739,793 to Wilson. 
     Some conditions, such as Parkinson&#39;s disease, can contribute to a progressive degeneration of the abdominal muscles, which makes sitting up without assistance difficult or impossible. Temporary conditions, such as recovery from abdominal surgery, can also leave the abdomen weak. Relatively few references deal with bed ingress and egress assistance devices which provide assistance to individuals in sitting up in bed. One reference that does teach such a device is U.S. Pat. No. 4,679,265 to Wicks. Wicks teaches a tether hooked to an anchoring member, which is provided by a U-shaped hook sized to be fitted around the foot of a bed mattress. Using the tether a person can help themselves sit up from a recumbent position by pulling themselves up on the tether. While the device is exceedingly simple and unobtrusive, it is unclear how the tether remains positioned for easy grasping by the bed occupant over the course of a night. Nor does the system do anything for individuals who have lost substantial upper body strength. A trapeze system is taught in U.S. Pat. No. 4,686,727 to Wilkinson, which provides assistance to patients in sitting up from bed. Another such system is that taught in U.S. Pat. No. 4,253,207 to Marcyan. In trapeze systems a bar or handle is suspended over the bed for grasping by the bed occupant. 
     A common theme among several references is ease of installation and portability, which is carried out in part by tubular construction of rail systems and extensions of the tubing to fit under and to be anchored by the bed&#39;s mattress. U.S. Pat. No. 5,471,689 to Shaw is an example of a device incorporating such features. 
     The present applicant taught a patient self-assist transfer aid for use with a bed in a prior application, now U.S. Pat. No. 6,425,154. The self-assist transfer aid comprises an open box frame having a base for fitting beneath a mattress of a bed, a riser section extending upwardly from the base around an outside edge of the mattress and a positioning section for extending out over the mattress from the riser section. The open box frame may be positioned around the mattress end at the foot of the bed to leave the major sides of the bed open for ease of access. A linkage is fitted to the positioning section of the open box frame and may be extended therefrom to position a handle within easy grasp of a person lying in the bed or laying down on the bed. A spring system biases the linkage to a retracted position in the open box frame. A handle is pivotally attached to the linkage and for grasping by a patient lying in the bed or lowering him or herself into bed. 
     SUMMARY OF THE INVENTION 
     An object of the invention is to provide an apparatus aiding the infirm in getting into and out of bed by helping the person move from a standing position adjacent the bed to a recumbent position on the bed and back. 
     Another object of the invention is to provide a patient mobility aid for use with beds which does not limit access to the bed. 
     It is a still further object of the invention to provide an aid for use with beds which is readily removed or placed in the bed. 
     It is yet another object of the invention to provide patient control for a motorized lift system. 
     According to the invention there is provided a motorized patient transfer system for use with a bed. The transfer system comprises an open frame having a flattened base positionable beneath a mattress of a bed, a riser section extending upwardly from the base around an outside edge of the mattress and a positioning section extending out over the mattress from the riser section. The open frame may be positioned at the foot of the bed around an end, preferably the foot, of the bed to leave the major sides of the bed open for ease of access. A linkage is fitted to the positioning section of the open frame and supports a handle which may be extended therefrom to within easy reach of a person lying in the bed or laying down on the bed. The handle is pivotally attached to the linkage for grasping by a patient lying in the bed or lowering him or herself into bed. A spring system biases the linkage toward an extended position outward from the open frame toward the head of the bed. A retraction motor is mounted on the frame and coupled to the linkage by a flexible cable and constant rotation direction payout pulley for retracting the linkage and handle. The retraction motor is controlled from a switch mounted within the reach of the patient. 
     Additional effects, features and advantages will be apparent in the written description that follows. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The novel features believed characteristic of the invention are set forth in the appended claims. The invention itself however, as well as a preferred mode of use, further objects and advantages thereof, will best be understood by reference to the following detailed description of an illustrative embodiment when read in conjunction with the accompanying drawings, wherein: 
     FIGS. 1A-B are perspective views of a preferred embodiment of the self-assist mobility aid of the invention; 
     FIG. 2 is a side elevation view of the embodiment of FIGS.  1 A/B. 
     FIGS. 3A-B are top plan views of the invention. 
     FIG. 4 is a cross sectional view of an extensible piston rod used in the first embodiment. 
     FIG. 5 is a circuit diagram of the motor actuation circuit. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring now to FIGS. 1A,  1 B and  2 , a preferred embodiment of transfer system  10  of the present invention is illustrated. Transfer system  10  comprises a box frame  11  which is shaped to provide a base  200  which fits between a mattress  16  and a foundation  18  such as box springs or a bed platform. So positioned, frame  11  rests on its base, extending from one edge of the base around an edge of the mattress  16 , preferably the end of the mattress located at the foot of a bed. From the exposed edge of the base frame  11  rises vertically for a distance and then bends back over mattress  16 . The end of frame  11  opposite the base is thus suspended over mattress  16 . On the end of frame  11  over mattress  16 , a handle  12  and a support brace  14  are positionable for the use of a person getting into and out of bed. Normally, a person lying on mattress  16  can grab handle  12  when extended and be pulled to a sitting position by the handle as it is retracted. For individuals with limited use of their arms, a harness  92  may be attached to handle  12  by straps  93  and  95 . The individual can than fit harness  92  around their back with the straps  93  and  95  extending from under their arms to be pulled to a sitting position. Alternatively, handle  12  can be removed and harness  92  fitted directly to the linkages used for attachment of the handle to frame  11 . 
     The upper section of frame  11 , corresponding in part to arms  23  and  27 , slants downwardly from a location over the end of the mattress  16  toward the head of the bed. Handle  12  is movable on frame  11  from the end of the frame over the bed in the directions indicated by double arrow “A”. Handle  12  thus may be extended somewhat downwardly toward the head of the bed (illustrated in FIG. 4) and retracted back into frame  11 . Handle  12  is disposed on rods which extend from within frame tubes  20  and  24  and which are spring biased to urge the handle outwardly from frame  11  out over mattress  16  toward the head of the bed. A handle retraction motor  111  is mounted to frame  11  on cross member  32  and is connected to handle  12  by a flexible tether  113  set on a pulley (illustrated below). Tether  113  provides for retracting handle  12  into frame  11  with sufficient force to overcome the bias of the spring. When the weight of a person&#39;s torso hangs from handle  12  the person is gently lowered onto the bed from a sitting position and can, from a recumbent position, pull the handle towards themselves. Handle  12  is also rotatable in the directions indicated by double arrow “B” on an axis which is parallel to the upper major surface of mattress  16  to allow the handle to be pushed out of the way or pulled to a more convenient position. 
     A support brace  14  is also mounted to a cross member  34  near the upper end of frame  11 . Support brace  14  may be rotated in the directions indicated by double arrow “C” about an axis substantially perpendicular to the upper major surface of mattress  16 . Brace  14  may be moved out over one of the major edges of mattress  16  to provide support to a person moving from a standing position along side the bed to a sitting position on mattress  16 , or from a sitting position on the mattress to standing alongside the bed. 
     Frame  11  is constructed from two tubular members  20  and  24 , and a plurality of transverse cross members  28 ,  30 ,  32  and  34 . Each tubular member has, in turn, three major sections corresponding to the principal parts of the frame  11 . For tubular member  20  there is a base leg  21 , an upright  22  and a positioning arm  23 . Tubular member  20  is preferably formed from a single tube with curved transition sections between the major sections. Similarly, tubular member  24  has a base leg  25 , an upright  26  and a positioning arm  27 . 
     Frame  11  has three major sections, defined by their respective functions, which are: as a base or foundation for the frame; as a riser disposed between the base and an upper support platform to allow positioning of the frame around an edge of the bed; and as a platform positioned above the bed for the active elements of the support system  10 . Frame  11  stands on one side of the frame, comprising base legs  21  and  25  and cross member  28 , which form the base. The base is illustrated as positioned below a mattress  16 , which stabilizes frame  11  on a box spring or platform  18 . The riser corresponds to vertical uprights  22  and  26  and cross member  30 . The platform to position patient aid braces and handles within easy reach of a patient is formed by arms  23  and  27  along with cross members  32  and  34 . 
     Vertical support for arms  23  and  27  is provided by vertical uprights  22  and  26 , respectively. Uprights  22  and  26  are braced against on one another be cross member  30 . Positioning arms  23  and  27  depend from uprights  22  and  26 , respectively, and are linked to one another by cross members  32  and  34 . Cross members  28 , 30 ,  32  and  34  are attached to tubular members  20  and  24  by suitable fastening means. For cross members  28 ,  30  and  32  these may include penetration of the tubular members  20  and  24  by the ends of the cross members coupled with screws through the bodies of the tubular members into the cross members. Cross member  34  serves other functions and is attached to tubular members  20  and  24  somewhat differently as is described below. Frame  11  generally defines a U-shaped frame, which can be fitted around one edge of bed mattress and which is held in place by the mattress. 
     Specific construction elements, such as tubular frames, joints, bends and cross members, including consideration of their size and material may vary upon specific application of the device, for example in houses or health care facilities, or the type of bed used. Spring types, fasteners and the like may be chosen based on cost considerations or the desire for the highest refinement of the tool. The basic design concept would be unchanged. For example, hospital and nursing home beds are different than beds normally found in individual houses or apartments in that a spring grid is all that is provided immediately under the top level bedding element. No box spring is provided and as a result no integral surface exists as a base. In such an application a tubular frame base would not be appropriate. In some applications welded joints joining distinct tubes may be used in place of a single bent tubes, or rectangular tubing may be used instead of circular cross-section tubing to enhance rigidity. The retraction motor is preferably of a type generating high torque at low rotational speeds, such as provided by vehicle windshield wiper motor. 
     FIG. 2 is a side elevation of frame  11  illustrating more fully tubular member  20  and the position relative thereto of handle  12 . Brace  14  swings on a pivot axis  70  which is perpendicular to the upper major surface of mattress  16 . A plurality of screws  80  are set in tubular member  20  hold cross members  28 ,  30  and  32  in place. Similar screws (not shown) join the cross members  28 ,  30  and  32  to tubular member  24 . 
     Referring now to FIGS. 3A-B and  4 , the mechanical details relating to positioning of handle  12  are illustrated. Handle  12  is mounted on co-axial pivoting mounts  42  and  44 , which are provided by rods  50  and  52  to position a gripping section  36  within easy reach of a person laying in a bed. Rods  50  and  52  are mounted in cylinders  46  and  48  with rod exerts  54  and  56  extending from the cylinders to mate with holes through handle arms  38  and  40 , respectively. Appropriate threaded nuts or other fastening elements may be used to hold handle  12  on rod exerts  54  and  56 . 
     Retraction of handle  12  is powered by a motor  111 , which is mounted on a platform  123  which in turn is set on cross rod  32 . Motor  111  is turned on by depression of either of switch pads  115  which may be placed on handle  12  to be easily reached by a user. The position indicated for switch pads  115  is illustrative only and many other locations may be used for the control switch such as a free box which may be placed on an adjacent table. Typically the switches will be spring loaded and will cut off if continuous pressure is not applied. Motor  111  turns a shaft  127  which in turn drives a constant rotation direction pulley  125 . Tether system  113  is connected to retract a cable between pivot mounts  42  and  44  and the constant rotation direction payout pulley  125  to effect retraction of handle  12 . Tether system  113  comprises a base cable  121  which winds on pulley  125 . Cable  121  divides into two parts,  117  and  119  which are looped through holes  97  and  99  in extensions  83  and  85 , which depend from mounts  42  and  44 , respectively. Tether segments  117  and  119  feed though openings  150  and  152  through cross member  34 . 
     Extension and retraction of handle  12  relative to frame  11  is supported on piston rods  62  and  64 , which extend from the bases of mounting cylinders  46  and  48 , respectively, and which are partially inserted into the open ends of positioning arms  23  and  27 . Rods  62  and  64  are free to move in and out of positioning arms  23  and  27  except as limited rod ends  67  and  69  and by restraining caps  78  and  80 . Restraining caps  78  and  80  close the open ends of positioning arms  23  and  27  save for annular openings sized to pass rods  62  and  64 . Restraining caps  78  and  80  are of smaller diameter than the width of rod ends  67  and  69 . This allows the free traversal of the rods  62  and  64 . 
     Referring to FIG. 4, a cross sectional view of arm  27  illustrates a spring biasing mechanism applicable to both arms. Compression spring  68  biases rod  64  outwardly from the tube forming positioning arm  27  toward an extended position. Compression spring is located between a piston rod shoulder stop  76  located around piston rod  64  and a screw  220  which positions one end of cross member  32 . If desired, the force generated by spring  68  may be adjusted by building up shoulder  76 , or by selecting a spring with a different spring constant. 
     For a patient with minimal upper body strength and no abdominal strength, handle  12  should be easily drawable, if speed limited, the retractive force applied by the tether  113  balancing the outward force supplied by spring  68  and a comparable spring in arm  23 . Retractive force, overcoming the spring forces and supporting the weight of the patient is supplied by motor  111 . The maximum speed of extension may be set by limiting the speed at which constant rotation direction payout pulley  125  can turn. 
     Brace  14  is pivotally mounted to an extension of cross member  34 , which positions the pivot  70  for the brace at a point horizontally displaced from the upper or positioning section of frame  11  toward an edge of the bed. A pivot stop  72  limits travel of brace  14  toward the center of the bed and allows the infirm user of the apparatus to pull him or herself around to bring their legs over the edge of the bed. Brace  14  may then be pivoted outwardly over the edge of the bed, or to other convenient positions, to provide a support for the individual as he or she stands. It should be apparent that brace  14  and handle  12  may be used to reverse the process as well. 
     FIG. 5 illustrates a simple series circuit suitable for providing energization of motor  111 . A power supply  131  may be connected to motor  111  by simple closure of switch  115 . As stated above, switch  115  is biased open. Wires for switch  115  are typically snaked through the tubing of the handle and of frame  11  to reach motor  111 . Where handle  12  is removed for a harness an independent switch box may be provided. 
     The present invention aids the infirm in getting into and out of bed, generally without assistance of another individual, or in the case where two elderly persons live together, eases the task of helping another person out of bed. The preferred embodiment is readily installed on most beds, requiring no permanent physical modification of the bed, and is readily removed if desired. When positioned with a bed the apparatus does not limit access to the bed by blocking the major sides with rails. 
     While the invention is shown in only one of its forms, it is not thus limited but is susceptible to various changes and modifications without departing from the spirit and scope of the invention.