Abstract:
A wheelchair transfer device is configured for moving an invalid patient from a flat surface to a seated position for transport in the seated position on the transfer device. The transfer device includes a rolling base supported by casters and convertible low profile rollers that are configured to fit under the base of a hospital bed and convert to a larger diameter wheel without altering the height of the transfer device. The transfer device includes a leg portion, a torso portion and a seat portion configured to be coplanar for adaptation to a hospital bed, so that an invalid patient can, with assistance, roll onto the device. The seat portion can then be raised against the patient&#39;s buttocks, generally perpendicular to the leg and torso portions, and the whole assembly can then be rotated to a vertical position, with the seat portion supporting the weight of the patient.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of U.S. Provisional Application Ser. No. 60/741 203, filed Dec. 1, 2005, which is incorporated herein in its entirety. 
    
    
     FIELD OF THE INVENTION 
     The invention relates to patient transfer devices for moving a patient from a recumbent position to a seated position. 
     BACKGROUND OF THE INVENTION 
     Patients often require assistance in moving from a hospital bed to a wheelchair, or require assistance in moving from the hospital bed to a toilet. An attendant rendering assistance is subject to injury in assisting the patient without mechanical assistance. Patient transfer devices can still require excessive bending and lifting by an attendant, increasing the likelihood of injury to the attendant or patient. In the alternative, some patient transfer devices, such as an overhead lift, can make the patient feel like freight due to the lack of any personal contact by an attendant. 
     It would be advantageous to provide a patient transfer device that gives an attendant the mechanical advantage necessary to move a patient without injury, and that maintains the close personal contact between the patient and the medical attendant. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The present invention will become more fully understood from the detailed description and the accompanying drawings, wherein: 
         FIG. 1  is a perspective view of a patient transfer device according to the invention. 
         FIG. 2  is a further perspective view of the patient transfer device of  FIG. 1 . 
         FIG. 3  is a front view of the patient transfer device of  FIGS. 1-2  in a reclined position. 
         FIG. 4  is a front view of the patient transfer device of  FIGS. 1-3  in a reclined position with a seat portion raised. 
         FIG. 5  is a front view of the patient transfer device of  FIGS. 1-4  in an upright position. 
         FIG. 6  is an enlarged detail view according to  FIG. 5 . 
         FIG. 7  is a perspective view of the patient transfer device of  FIGS. 1-6  adjacent a hospital bed, in the reclined position. 
         FIG. 8  is a perspective view of the patient transfer device of  FIGS. 1-7  adjacent a hospital bed, in the seat raised position. 
         FIG. 9  is a perspective view of the patient transfer device of  FIGS. 1-8  adjacent a hospital bed, in the upright position. 
         FIG. 10  is a perspective view of the patient transfer device of  FIGS. 1-9  adjacent a hospital bed, with the base in a positioning configuration. 
         FIG. 11  is a perspective view of the patient transfer device of  FIGS. 1-10  adjacent a hospital bed, with the base in a transporting configuration. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Certain terminology will be used in the following description for convenience and reference only, and will not be limiting. For example, the words “upwardly”, “downwardly”, “rightwardly” and “leftwardly” will refer to directions in the drawings to which reference is made. The words “inwardly” and “outwardly” will refer to directions toward and away from, respectively, the geometric center of the arrangement and designated parts thereof. Said terminology will include the words specifically mentioned, derivatives thereof, and words of similar import. 
     Referring to  FIGS. 1-3 , the device  100  includes a rolling base unit  105  and an upper unit  110 . The rolling base unit  105  includes a pair of caster wheels  112 ,  114  and a pair of dual height roller wheels  116 ,  118 . An adjustable height stanchion  120  projects upwardly from the rolling base unit  105 . The upper unit  110  is secured to an upper end  122  of the stanchion  120 .  FIGS. 1-2  provide perspective views of the device  100  with the upper unit  110  in an upright seating position.  FIG. 3  is a side view of the device  100  with the upper unit  110  in a prostrate position. 
     The rolling base unit  105  further includes an adjustment mechanism  124 . The adjustment mechanism  124  selectively rotates the dual height roller wheels  116 ,  118  from a raised position ( FIG. 1 ), wherein the base unit  105  is supported on the rolling surfaces of the wheels  116 ,  118 , to a lowered position ( FIG. 10 ) offset from the raised position by 90 degrees, wherein the base unit  105  is supported by a roller bearing  126  mounted in the center of each roller wheel  116 ,  118 . This operation is described in greater detail in commonly owned U.S. Ser. No. 11/354 801, filed Feb. 15, 2006, which is incorporated herein by reference in its entirety. 
     The upper unit  110  includes a frame support member  200  that is secured to the upper end  122  of the stanchion  120 . The frame support member  200  supports a pivot pin  205  defining a pivot axis  210 . A pivoting wheelchair frame  215  is pivotally mounted to the frame support member  200  by the pivot pin  205  and is configured to pivot about the pivot axis  210 . 
     The frame  215  is formed of two major components, a seat frame  220  and an upper torso support frame  225 . The seat frame  220  and the upper torso support frame  225  are each independently pivotally mounted to the support member  200  to rotate about the pivot axis  210 . 
     The seat frame  220  is formed of a generally U-shaped tubular member  230  having inner and outer legs  232 ,  234 . The inner leg  232  is pivotally connected to the support member  200 . A transverse seat support member  236  is attached at the uppermost extent  238  of the outer leg  234 . 
     The upper torso support frame  225  is attached to the support member at an inner end  240 . The frame  225  includes an upturned outer end  242 . A transverse seat support member  244  is attached to the frame  225  at the outer end  242 . A flexible seat body  250  extends between the transverse seat support members  236 ,  244 . 
     The seat frame  220  and the upper torso support frame  225  are joined by an attitude fixing mechanism  260 . The attitude fixing mechanism  260  is pivotally mounted at a first end  262  to the seat frame  220  by a pivot pin  264 . A second end  266  of the attitude fixing mechanism  260  is selectively fixable on the upper torso support frame  225 . The frame  225  includes a yoke  268  having a through-pin  270 . The second end  266  of the attitude fixing mechanism  260  includes a plurality of recesses  272 . The attitude fixing mechanism  260  is receivable within the yoke  268  in such a manner that the pin  270  is positioned to selectively engage one of the plurality of recesses  272 . The fixing mechanism  260  further includes a spring clip  275  positioned proximate the second end  266  and configured to bear against the frame  225  for urging the fixing mechanism  260  away from the frame  225 , and thus urging the pin  270  into a respective one of the plurality of recesses  272 . 
     A second frame support member  280  is rigidly attached to the stanchion  120 . The support member  280  supports a drive mechanism  290 . The drive mechanism  290  is pivotally connected to the support member  280  at a lower pivot  295  and to the upper torso support frame  225  at an upper pivot  300 . In the illustrated embodiment, the drive mechanism  290  is an electric drive mechanism, but hydraulic, pneumatic or other mechanical drive types are also anticipated. 
     The drive mechanism  290  is electrically connected to a controller/battery module  310  by a control cable  312 . The controller/battery module  310  is suspended from the support member  280 . A remote control switch panel  320  is provided and is shown mounted on the upper torso support frame  225 . The remote control switch panel  320  is further electrically connected to the controller/battery module  310  by a further control cable  322 . 
     A knee-board  330  is mounted to the upper torso support frame  225 . The knee-board  330  is rigidly mounted to the frame  225  and is mounted parallel thereto. 
     Referring to  FIG. 4 , the seat portion  220  has been rotated counterclockwise 90 degrees about the pivot axis  210 . As the seat portion  220  rotates counterclockwise about the pivot axis  210 , independent of the upper torso support frame  225 , the fixing mechanism  260  is drawn through the yoke  268 . The recesses  272  sequentially line up with the pin  270 , enabling the seat portion  220  to be selectively locked in multiple angular positions with respect to the upper torso support frame  225 . As the seat portion  220  reaches the 90 degree rotation shown in  FIG. 4 , the endmost recess  272  reaches the pin  270  in the yoke  268 . With the pin  270  lodged in the endmost recess  272 , the seat portion  220  is secured in a 90 degree relationship to the upper torso support frame  225 . 
     Referring now to  FIGS. 5-6 , the device  100  is shown with the upper unit  110  in the upright seated position. The upper torso support frame  225  and the seat portion  220  are rotated together into the upright position. In this position, the seat portion  220  is supported by the frame support member  200  on the stanchion  120 . The upper torso support frame  225  is supported in the upright position by the drive mechanism  290 . As shown in  FIG. 5 , the drive mechanism  290  is in an extended condition. Since the drive mechanism  290  pivots about the lower pivot  295  and the upper pivot  300 , which are offset from the pivot axis  210 , the extension of the drive mechanism  290  forces the upper torso support frame  225  to pivot about the pivot axis  210 . 
     Operation 
     The device  100  is configured for raising a patient from a reclining position to a seated position. Referring first to  FIG. 7 , the device  100  is positioned adjacent to a bed  400  with the upper unit  110  in the prostrate position. In this position, the seat body  250  is horizontal and is positioned at the height of the patient support surface  405  of the bed  400  using the adjustable height stanchion  120 . As necessary, the dual height wheels  116 ,  118  are placed in the low profile position to roll under the base of the bed  400 , and the device  100  is rolled to the bed  400  so that the seat body  250  overlies a portion of the patient support surface  405 . In the configuration of the single step wheelchair transfer device  100  illustrated herein, the device  100  is rolled to the “left” side of the bed  400 ; the patient&#39;s head is also to the left as viewed from beside the bed  400 . In a further configuration (not shown), the device  100  is configured to roll to the “right” side of the bed  400 ; this is advantageous where access to the left side of the bed  400  is restricted, or where the patient is laying with his head to the right from the perspective of the device  100 . In a further embodiment, the device is capable of being selectively configured in either the “left” side or “right” side configurations, thereby providing the attendant with the flexibility to operate in different room and equipment layouts using one single step wheelchair transfer device  100 . 
     Typically, the patient will be rolled away from the device  100 , and the device  100  rolled over the portion of the patient support surface  405  previously occupied by the patient. The patient is then rolled back onto the positioned device  100 . The patient is then further rolled toward the device  100  until the patient is lying on his side on the seat body  250 . The patient&#39;s legs are then drawn outward until the patient&#39;s knees and lower legs are resting on the knee-board  330 . 
     Referring now to  FIG. 8 , the seat portion  220  of the upper unit  110  is rotated upwardly until it reaches the upright position, 90 degrees from the patient support surface  405 . The seat portion  220  is automatically locked in the 90 degree position as the fixing mechanism  260  slides through the yoke  268  until the pin  270  engages the last recess  272  on the fixing mechanism  260 . With the seat portion  220  in this position, the seat body  250  contacts the buttocks and the backs of the upper thighs of the patient. 
     The device is now ready to be moved to the upright seated position. An attendant will use the remote control switch to activate the drive mechanism  290 . As the drive mechanism  290  is activated and drives from a retracted position to an extended position (see also  FIG. 5 ), the upper unit  110  rotates from the prostrate position to the upright seated position shown in  FIG. 9 . The knee-board  330  is fixed to the upper torso support frame  225  and rotates therewith, supporting the patient&#39;s knees and lower legs through the rotation cycle as the upper unit  110  comes to the upright position. The patient is now raised to the position of sitting on the edge of the patient support surface  405 . 
       FIGS. 10-11  illustrate the movement of the device  100  away from the bed  400 . Safety belts (not shown) can be provided to secure the patient to the device  100 , who is otherwise closely attended by an attendant. In  FIG. 10 , the dual height wheels  116 ,  118  are in the low profile position for maneuvering under the base of the bed. In  FIG. 11 , the dual height wheels have been rotated to the high profile position, better suited for transporting a patient over longer distances or uneven surfaces. In this configuration, the device can be used directly as a wheelchair for special purpose movement, such as for transporting a patient to the bathroom. The device  100  can also be made waterproof for use directly in the shower, eliminating the need to lift or move the patient again once the patient has been lifted and carried by the device  100 . 
     While the invention has been described in the specification and illustrated in the drawings with reference to a preferred embodiment, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention as defined in the claims. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment illustrated by the drawings and described in the specification as the best mode presently contemplated for carrying out this invention, but that the invention will include any embodiments falling within the scope of the appended claims.