Patent Publication Number: US-9414980-B2

Title: Bed, and combining method and separating method of bed

Description:
TECHNICAL FIELD 
     The present invention relates to a bed in which a part thereof can be separated as a wheelchair, and a combining method and a separating method of the bed. 
     BACKGROUND ART 
     In a hospital or a nursing care facility, for example, a patient, a care-receiver, or the like (hereinafter, abbreviated as the care-receiver) is required to move to other places from a state where the care-receiver lies on a bed in a hospital room many times a day. At this time, transferring of the care-receiver from the bed to a wheelchair is usually manually performed by a nurse, a caregiver, or the like (hereinafter, abbreviated as the caregiver). By such transferring, the caregiver bears a physical burden. 
     In order to reduce the physical burden on the caregiver by the transferring of the care-receiver, a bed in which a part of the bed is separated therefrom so as to be utilized as a wheelchair is proposed. 
       FIG. 12  shows a conventional bed  1 . A bed surface of the bed  1  is composed of three plates of a side bed plate  2 , a center bed plate  3 , and a side bed plate  4 . In order to compose the bed surface, there is a need for moving the center bed plate  3  of a platform truck  5  to a space  3   a  between the side bed plate  2  and the side bed plate  4 . A caregiver brings up the side bed plate  4  to an upper side of a bed main body  6  taking a rotation mechanism  7  as a rotation center. 
     The caregiver moves the center bed plate  3  to the space  3   a  in a state where the side bed plate  4  is brought up to the upper side of the bed main body  6 . By returning the side bed plate  4  to an original position after moving the platform truck  5  to the space  3   a , the bed surface of the bed  1  is composed. 
     The platform truck  5  separated from the bed  1  can also be used as a wheelchair. In that case, the center bed plate  3  serves as a seating bottom of the wheelchair. 
       FIG. 13  is a side view of the platform truck  5 . The platform truck  5  has a chair posture change mechanism in which a leg portion  3   c  is inclined in conjunction with an inclination of a back surface portion  3   b  in order to simply change the center bed plate  3  from a flat posture to a seating posture. When the back surface portion  3   b  is lifted upward until the back surface portion  3   b  becomes substantially vertical, the leg portion  3   c  is lowered downward via a first link  8   a  and a second link  8   b . That is, only by lifting the back surface portion  3   b , the leg portion  3   c  is lowered downward, and the flat posture is changed to the seating posture. Therefore, the caregiver can simply perform posture change of the wheelchair (for example, refer to Patent Literature 1). 
     CITATION LIST 
     Patent Literature
     [Patent Literature 1] Japanese Unexamined Utility Model Publication No. 5-51330   

     TECHNICAL PROBLEM 
     A bed for nursing care requires a flat posture in which a bed surface is flat, a back lifting posture in which a back part of the bed surface is lifted, and a knee lifting posture in which a knee part of the bed surface is lifted. In a conventional bed  1 , a bed surface can be composed of a side bed plate  2 , a center bed plate  3 , and a side bed plate  4  in the flat posture. However, the conventional bed  1  has such a construction that parts of the side bed plate  2  and the side bed plate  4  of the conventional bed  1  cannot be lifted. Therefore, in the conventional bed  1 , the back lifting posture or the knee lifting posture cannot be composed of the entire bed surface, but the back lifting or the knee lifting is performed only by the center bed plate  3 . That is, in the conventional bed  1 , the back lifting posture or the knee lifting posture as well as a general nursing care bed cannot be composed. 
     SUMMARY OF INVENTION 
     The present invention is to solve such a problem, and an object thereof is to provide a bed in which posture change can be performed to form the flat posture, the back lifting posture, and the knee lifting posture as well as the general nursing care bed when a wheelchair is combined with the bed, and a combining method and a separating method of the bed. 
     Solution to Problem 
     In order to achieve the above object, the present invention is configured as below. 
     In order to achieve the above object, a bed of the present invention, comprises: a support switching mechanism, the bed being composed of separably combining a wheelchair and a bed main body portion, 
     the wheelchair comprising:
         a seating bottom portion composed of bendably coupling a plurality of divided members to each other; and   a chair bottom support member supporting the seating bottom portion,       

     the bed main body portion comprising:
         a bed bottom portion composed of bendably coupling a plurality of divided members to each other; and   a bed bottom support member supporting the bed bottom portion,       

     the support switching mechanism switching a support member of the seating bottom portion of the wheelchair between the chair bottom support member and the bed bottom support member. 
     Further, in order to achieve the object, a combining method of a bed of the present invention comprises a support switching mechanism, the combining method for separably combining a wheelchair and a bed main body portion, wherein 
     the wheelchair comprises: a seating bottom portion composed of bendably coupling a plurality of divided members to each other; and a chair bottom support member supporting the seating bottom portion, and 
     the bed main body portion comprises: a bed bottom portion composed of bendably coupling a plurality of divided members to each other; and a bed bottom support member supporting the bed bottom portion, 
     the combining method comprising: switching a support member supporting the seating bottom portion of the wheelchair from the chair bottom support member to the bed bottom support member by the support switching mechanism in a case where the wheelchair and the bed main body portion are combined. 
     Furthermore, in order to achieve the object, a separating method of a bed of the present invention combinably separates a wheelchair and a bed main body portion, wherein 
     the wheelchair comprises: a seating bottom portion composed of bendably coupling a plurality of divided members to each other; and a chair bottom support member supporting the seating bottom portion, and 
     the bed main body portion comprises: a bed bottom portion composed of bendably coupling a plurality of divided members to each other; and a bed bottom support member supporting the bed bottom portion, 
     the separating method comprising: switching a support member supporting the seating bottom portion of the wheelchair from the bed bottom support member to the chair bottom support member in a case where the wheelchair and the bed main body portion are separated. 
     Advantageous Effects of Invention 
     In the present invention, when the wheelchair is combined with the bed, the seating bottom portion of the wheelchair is supported by the bed bottom support member. Thus, by the bed bottom support member, the seating bottom portion of the wheelchair and the bed bottom portion of the bed main body portion can integrally perform the posture change. Therefore, according to the present invention, the bed in which the posture change can be performed as well as a general nursing care bed, and the combining method and the separating method of the bed can be provided. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
       These and other aspects and features of the present invention will become clear from the following description taken in conjunction with the preferred embodiments thereof with reference to the accompanying drawings, in which: 
         FIG. 1A  is a schematic perspective view at the time of separation of a bed in a first embodiment of the present invention; 
         FIG. 1B  is a schematic perspective view at the time of combination of the bed in the first embodiment of the present invention; 
         FIG. 1C  is a block diagram of a control section and the like of the bed in the first embodiment of the present invention; 
         FIG. 2A  is a perspective view of a wheelchair in a seating posture state in the first embodiment; 
         FIG. 2B  is a schematic side view of a link mechanism of the wheelchair in the first embodiment in a flat posture state; 
         FIG. 2C  is a schematic side view of the link mechanism of the wheelchair in the first embodiment in the seating posture state; 
         FIG. 3A  is a perspective view of the bed at the time of the separation when the wheelchair is in a flat posture in the first embodiment; 
         FIG. 3B  is a schematic side view of a link mechanism of a bed main body portion in the first embodiment in the flat posture state; 
         FIG. 3C  is a schematic side view of the link mechanism of the bed main body portion in the first embodiment in the seating posture state; 
         FIG. 4A  is a front view in which the bed with a posture change mechanism being switched is seen from the front side of the bed in a state where a seating bottom portion is supported by a chair bottom support member in the first embodiment; 
         FIG. 4B  is a front view of a state where the seating bottom portion is supported by a bed bottom support member in a state where the seating bottom portion is supported by the chair bottom support member in the first embodiment; 
         FIG. 5  is a perspective view of the bed at the time of the combination in the flat posture state in the first embodiment; 
         FIG. 6  is a perspective view of the bed in back lifting posture and knee lifting posture states in the first embodiment; 
         FIG. 7A  is a side view of the bed in the back lifting posture and knee lifting posture states and in a bed lowering state in the first embodiment; 
         FIG. 7B  is a side view of the bed in the back lifting posture and knee lifting posture states and in a bed raising state in the first embodiment; 
         FIG. 8  is a flowchart of a combining method of the bed in the first embodiment; 
         FIG. 9  is a view showing an operating surface of an operating remote controller in the first embodiment; 
         FIG. 10  is a flowchart of a separating method of the bed in the first embodiment; 
         FIG. 11A  is a schematic perspective view at the time of separation of a bed in a second embodiment of the present invention; 
         FIG. 11B  is a schematic perspective view at the time of combination of the bed in the second embodiment of the present invention; 
         FIG. 12  is a perspective view of the bed with a conventional wheelchair serving as a part of the constituent of the bed; and 
         FIG. 13  is a perspective view of the conventional wheelchair. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     Hereinafter, embodiments of the present invention will be described with reference to the drawings. It should be noted that the identical constituent elements will be given the identical reference numerals, and description thereof will sometimes be omitted. For easy understanding, the figures are schematic focusing on the constituent elements. 
     First Embodiment 
       FIGS. 1A and 1B  are schematic perspective views of a bed  11  in a first embodiment of the present invention. The bed  11  of the first embodiment is composed of combining a separable wheelchair  9  and a bed main body portion  10 .  FIG. 1A  is a schematic perspective view of the bed  11  when the wheelchair  9  and the bed main body portion  10  are separated.  FIG. 1B  is a schematic perspective view of the bed  11  when the wheelchair  9  and the bed main body portion  10  are combined. 
     The bed  11  has a function of an electric nursing care bed whose posture is changed by electric drive sections, for example. The wheelchair  9  separated from the bed main body portion  10  has a function of a manual reclining wheelchair in which posture change is manually performed. 
     As shown in  FIG. 1A , the wheelchair  9  is composed of a seating bottom portion  15 , a chair bottom support member (chair guide member)  14 , a chair base portion  13 , and traveling wheels  12 . 
     The seating bottom portion  15  is composed of bendably coupling a plurality of plate shape chair bottom members (such as five chair bottom members  15   a ,  15   b ,  15   c ,  15   d ,  15   e ) at coupling parts, and they serve as parts to be respectively brought into contact with a body of a patient, a care-receiver, or the like (hereinafter, abbreviated as the care-receiver). 
     In the chair bottom support member  14 , a plurality of chair bottom support members  14   a ,  14   c ,  14   d ,  14   e  form a chair posture change mechanism  114  and support the seating bottom portion  15  so as to perform the posture change. 
     The chair base portion  13  supports the chair bottom support member  14  while allowing a bending action of the chair bottom support member  14 . 
     At least a pair of traveling wheels  12  is provided, and in this embodiment, four traveling wheels are rotatably provided on a lower part of the chair base portion  13 . The traveling wheels  12  movably support the chair base portion  13  and are capable of traveling on a ground (or an installment surface of the wheelchair  9  and the bed main body portion  10 )  44  along the horizontal direction, for example. 
     In the wheelchair  9 , when the posture change is performed by the chair bottom support member  14 , a posture of the seating bottom portion  15  is changed in accordance with the posture change of the chair bottom support member  14 . In the first embodiment, the plate shape chair bottom members  15   a ,  15   b ,  15   c ,  15   d ,  15   e  composing the seating bottom portion  15  of the wheelchair  9  are freely bent at the coupling parts. Therefore, the seating bottom portion  15  cannot maintain a fixed posture. The seating bottom portion  15  is supported by the chair bottom support member  14  serving as the posture change mechanism  114  of the wheelchair  9 . That is, in the first embodiment, the seating bottom portion  15  performs posture maintenance or the posture change integrally with a posture of the chair bottom support member  14 . 
     Meanwhile, as shown in  FIG. 1B , the bed main body portion  10  is composed of a bed bottom portion  17 , a bed bottom support member (bed bottom guide member)  18 , and a bed base portion  19 . 
     The bed bottom portion  17  is composed of bendably coupling a plurality of plate shape bed bottom members (such as four bed bottom members  17   a ,  17   b ,  17   c ,  17   d ) at coupling parts, and those members serve as parts to be respectively brought into contact with the body of the care-receiver. 
     In the bed bottom support member  18 , a plurality of bed bottom support members  18   a ,  18   c ,  18   d  compose a bed posture change mechanism  119 , and support the bed bottom portion  17  so as to be able to perform the posture change. 
     The bed base portion  19  supports the bed bottom support member  18  while allowing a bending action of this bed bottom support member  18 . A part corresponding to a recess portion  28  serving as an intermediate part of the bed base portion  19  and as a combination area is recessed in the width direction, so that the chair base portion  13  of the wheelchair  9  is insertable thereinto. 
     In this embodiment, four traveling wheels  25  are respectively rotatably provided on the front and rear sides of a lower part of the bed base portion  19 . The traveling wheels  25  movably support the bed base portion  19  and are capable of traveling on the ground (or the installment surface of the wheelchair  9  and the bed main body portion  10 )  44 . However, in the case where there is no need for moving the bed main body portion  10 , the traveling wheels  25  are not necessarily provided. 
     In the first embodiment, it is so constructed that the bed bottom members  17   a ,  17   b ,  17   c ,  17   d  composing the bed bottom portion  17  of the bed main body portion  10  are freely bent at the coupling parts. Therefore, the bed bottom portion  17  cannot maintain a fixed shape. Thus, the bed bottom portion  17  performs the posture maintenance or the posture change integrally with a posture of the bed bottom support member  18 . 
     The chair base portion  13  of the wheelchair  9  is moved in the width direction to and positioned in the recess portion  28  serving as the combination area provided on the side of the bed waist bottom member  17   b  between the bed back bottom support member  18   a  and the bed knee bottom support member  18   c . By this positioning, the wheelchair  9  and the bed main body portion  10  can be combined. In the first embodiment, in the case where the wheelchair  9  and the bed main body portion  10  are combined in such a way, a member supporting the seating bottom portion  15  is switched from the chair bottom support member  14  to the bed bottom support member  18  (that is, the seating bottom portion  15  is supported only by the bed bottom support member  18  instead of the chair bottom support member  14 ). An action of switching the member supporting the seating bottom portion  15  from the chair bottom support member  14  to the bed bottom support member  18  is performed by a support switching mechanism. The support switching mechanism is composed of an arrangement relationship between the chair bottom support member  14  and the bed bottom support member  18 , and an elevating section  27 . In the bed  11 , by switching the support member supporting the seating bottom portion  15  by this support switching mechanism, when the posture change is performed by the bed bottom support member  18 , the bed bottom portion  17  and the seating bottom portion  15  integrally perform the posture change. 
     At this time, the chair bottom support member  14  is in a flat posture as shown in  FIG. 1B  but substantially in contact with the bed main body portion  10 . Thus, the chair bottom support member  14  does not cause a disturbance in terms of structure. 
     That is, in the case where by moving the chair base portion  13  of the wheelchair  9  in the width direction and drawing out from the recess portion  28  serving as the combination area, the wheelchair  9  is separated from the bed main body portion  10 , the seating bottom portion  15  of the wheelchair  9  is supported only by the chair bottom support member  14  serving as the chair posture change mechanism  114  (that is, the seating bottom portion  15  is supported only by the chair bottom support member  14  instead of the bed bottom support member  18 ), and the posture change of the seating bottom portion  15  of the wheelchair  9  is performed by the chair bottom support member  14 . 
     Conversely, in the case where the wheelchair  9  and the bed main body portion  10  are combined, a posture change mechanism of the seating bottom portion  15  is switched from the posture change mechanism  114  having the chair bottom support member  14  to the posture change mechanism  119  having the bed bottom support member  18  by the support switching mechanism (that is, the seating bottom portion  15  is supported only by the bed bottom support member  18  instead of the chair bottom support member  14 ), and regarding the seating bottom portion  15  and the bed bottom portion  17 , the posture change of the seating bottom portion  15  of the wheelchair  9  and the posture change of the bed bottom portion  17  of the bed main body portion  10  are performed by the bed bottom support member  18  serving as the bed posture change mechanism  119 . 
     In such a way, by switching the posture change mechanism of the seating bottom portion  15  by the support switching mechanism between the time of separation and the time of combination of the bed  11 , the posture of the seating bottom portion  15  can be set to a seating posture (a posture in which the care-receiver is seated) as shown in  FIG. 1A  at the time of the separation, and the postures of the seating bottom portion  15  and the bed bottom portion  17  can be set to a back lifting posture and a knee lifting posture as shown in  FIG. 1B  at the time of the combination. Here, the back lifting posture indicates a state where the seating bottom portion  15  and the bed bottom portion  17  are inclined in such a manner that a back of the care-receiver supported by the seating bottom portion  15  and the bed bottom portion  17  becomes slightly rearward oblique relative to the vertical direction. The knee lifting posture indicates a state where the seating bottom portion  15  and the bed bottom portion  17  are bent into an inverted V shape in such a manner that knees of the care-receiver supported by the seating bottom portion  15  and the bed bottom portion  17  are bent into an inverted V shape. Therefore, the bed  11  in which a part of the constituent thereof is the wheelchair  9  does not require a specific control or a power source on the side of the wheelchair  9  but obtains the functions of both the reclining wheelchair and the nursing care bed. That is, even in the bed  11  in which a part of the constituent thereof is the wheelchair  9 , the knee lifting posture or the back lifting posture which is necessary as the nursing care bed can be composed. In the separated wheelchair  9 , a posture of a back surface part of the seating bottom portion  15  can be changed as a general wheelchair. 
     Further, at the time of the combination of the wheelchair  9  and the bed main body portion  10 , the seating bottom portion  15  and the bed bottom portion  17  are supported by the bed bottom support member  18 . Thus, the seating bottom portion  15  and the bed bottom portion  17  integrally perform the posture change. 
     Next, details of the wheelchair  9  and the bed main body portion  10  composing the bed  11  will be described. 
       FIG. 2A  is a perspective view of the wheelchair  9  in a seating posture state. 
     The chair base portion  13  has the four traveling wheels  12  in a lower part thereof. The wheelchair  9  is moved by these four traveling wheels  12 . In the first embodiment, there is no power in the wheelchair  9  but the wheelchair is moved by hand. The wheelchair  9  is moved when a nurse, a caregiver, or the like (hereinafter, abbreviated as the caregiver) pushes a handle  23  provided in the chair bottom support member  14 . 
     The seating bottom portion  15  is composed of the chair back bottom member  15   a , the chair waist bottom member  15   b , the chair knee bottom member  15   c , the chair leg first bottom member  15   d , and the chair leg second bottom member  15   e . Among the members composing the seating bottom portion, the adjacent members are bendably coupled to each other via the coupling parts of thin parts or hinges. The coupling parts of the thin parts may be composed of parts each having a thickness thinner than a thickness of each of the chair back bottom member  15   a  to the chair leg second bottom member  15   e  mainly composing the seating bottom portion  15 , and thereby the coupling parts are bendable. The chair back bottom member  15   a , the chair waist bottom member  15   b , the chair knee bottom member  15   c , the chair leg first bottom member  15   d , and the chair leg second bottom member  15   e  are parts to be brought into contact with a back, a waist, knees, legs, and heels of the care-receiver, respectively. The chair back bottom member  15   a , the chair waist bottom member  15   b , the chair knee bottom member  15   c , the chair leg first bottom member  15   d , and the chair leg second bottom member  15   e  usually each have a cushion function. It should be noted that the chair leg second bottom member  15   e  serves as a footrest when the wheelchair  9  is in the seating posture. 
     As shown in  FIG. 2B , the chair bottom support member  14  is composed of the square frame shape chair back bottom support member (chair back guide member)  14   a , the square frame shape chair knee bottom support member (chair knee guide member)  14   c , the square frame shape chair leg first support member (chair leg first guide member)  14   d , the square pole shape chair leg second support member (chair leg second guide member)  14   e , and four chair first to fourth bending portions  14   j ,  14   k ,  14   m ,  14   n  bendably coupling the adjacent support members each other. The chair back bottom support member  14   a  is capable of supporting the chair back bottom member  15   a . The chair base portion  13  is capable of supporting the chair waist bottom member  15   b . The chair knee bottom support member  14   c  supports the chair knee bottom member  15   c . The chair leg first support member  14   d  is capable of supporting the chair leg first bottom member  15   d . The chair leg second support member  14   e  is capable of supporting the chair leg second bottom member  15   e . The chair back bottom support member  14   a  and the chair waist bottom member  15   b  are bendably coupled to each other by the chair first bending portion  14   j . The chair waist bottom member  15   b  and the chair knee bottom support member  14   c  are bendably coupled to each other by the chair second bending portion  14   k . The chair knee bottom support member  14   c  and the chair leg first support member  14   d  are bendably coupled to each other by the chair third bending portion  14   m . The chair leg first support member  14   d  and the chair leg second support member  14   e  are bendably coupled to each other by the chair fourth bending portion  14   n . The handle  23  is fixed to a front end on the back surface side of the chair back bottom support member  14   a.    
     Since the chair waist bottom member  15   b , the chair back bottom support member  14   a , and the chair knee bottom support member  14   c  are coupled to one another, position displacement is not generated between the chair bottom member  15  and the chair bottom support member  14 . 
     The wheelchair  9  of this first embodiment is provided with a chair bottom support member biasing section for always imposing bias force on the chair back bottom support member  14   a  from the flat posture along the horizontal direction toward the seating posture oblique relative to the vertical direction. As one example of the chair bottom support member biasing section, a gas damper  20  is used. However, a translation actuator can be used instead. A hand brake  20   b  of the gas damper  20  is attached to the chair back bottom support member  14   a  beside the handle  23 , and the hand brake  20   b  and the gas damper  20  are coupled to each other by a brake wire  20   c . A piston rod  20   a  of the gas damper  20  is coupled to a front end of a branch coupling portion  14   f  branched on a back surface on the base end side of the chair back bottom support member  14   a . This piston rod  20   a  is capable of pivoting the chair back bottom support member  14   a  between the seating posture and the flat posture via the first bending portion  14   j  between the chair back bottom support member  14   a  and the chair waist bottom portion  15   b . An intermediate part of the branch coupling portion  14   f  of the chair back bottom support member  14   a  is coupled to a front end of a branch coupling portion  14   g  branched on a back surface of an end on the chair leg second bottom member side of the chair leg first support member  14   d  by a first coupling link member  14   p . Therefore, in the posture change mechanism  114  of the present embodiment, irrespective of a pivoting action of the chair back bottom support member  14   a  about the chair first bending portion  14   j , a gap between the intermediate part of the branch coupling portion  14   f  of the chair back bottom support member  14   a  and the front end of the branch coupling portion  14   g  of the chair leg first support member  14   d  is always the same. In the posture change mechanism  114 , a tensile force is imposed from the chair knee bottom support member  14   c  to the chair leg first support member  14   d  or the tensile force is cancelled in such a manner that the gap between the intermediate part of the branch coupling portion  14   f  and the front end of the branch coupling portion  14   g  is always the same. A front end of a branch coupling portion  14   h  and a front end of a branch coupling portion  14   j  are coupled to each other by a second coupling link member  14   q . Here, the branch coupling portion  14   h  is branched on a back surface of an end on the chair leg first support member side of the chair knee bottom support member  14   c . The branch coupling portion  14   j  is branched on a back surface of an end on the chair leg first support member side of the chair leg second support member  14   e . Therefore, irrespective of the pivoting action of the chair back bottom support member  14   a  about the chair first bending portion  14   j , a gap between the front end of the branch coupling portion  14   h  of the chair knee bottom support member  14   c  and the front end of the branch coupling portion  14   j  of the chair leg second support member  14   e  is always the same. As will be described later, when a shape of the seating bottom portion  15  of the wheelchair  9  is changed between the flat posture and the seating posture, the first coupling link member  14   p  and the second coupling link member  14   q  function to easily and reliably form the postures. 
     In the wheelchair  9 , the shape of the seating bottom portion  15  can be changed from the seating posture to the flat posture. Here, as shown in  FIG. 2A , the seating posture is a posture in which the chair back bottom member  15   a  is lifted, the chair knee bottom member  15   c  is inclined slightly upward relative to the chair waist bottom member  15   b , and the chair leg first bottom member  15   d  and the chair leg second bottom member  15   e  are lowered downward. As shown in  FIG. 3A , the flat posture is a posture in which the entire seating bottom portion  15  becomes a flat surface. 
     The seating posture will be described in detail based on  FIG. 2A . In the seating posture, the chair back bottom member  15   a  and the chair back bottom support member  14   a  stand up obliquely in the vertical direction in such a manner that upper ends thereof are positioned on the rear side of lower ends. The chair waist bottom member  15   b  is positioned substantially along the horizontal direction. The chair knee bottom member  15   c  and the chair knee bottom support member  14   c  are positioned slightly obliquely in such a manner that ends on the side of the chair waist bottom member  15   b  are positioned on the lower side of ends on the side of the chair leg first bottom member  15   d . The chair leg first bottom member  15   d  and the chair leg first support member  14   d  are positioned obliquely downward from ends on the chair knee bottom support member side to ends on the chair leg second bottom member side. The chair leg second bottom member  15   e  and the chair leg second support member  14   e  are positioned substantially in the horizontal direction or slightly obliquely upward from ends on the chair leg first bottom member side to a front end of the chair leg second bottom member  15   e.    
     In the flat posture, the chair back bottom member  15   a , the chair waist bottom member  15   b , the chair knee bottom member  15   c , the chair leg first bottom member  15   d , and the chair leg second bottom member  15   e  form one flat surface substantially along the horizontal direction. In other words, the chair back bottom support member  14   a , the chair knee bottom support member  14   c , the chair leg first support member  14   d , and the chair leg second support member  14   e  form one flat surface substantially along the horizontal direction, and this flat surface and the longitudinal directions of the first coupling link member  14   p , the second coupling link member  14   q , and the piston rod  20   a  of the gas damper  20  are parallel to each other. 
     That is, with the above configuration of the link mechanism of the wheelchair  9 , when the caregiver grips the hand brake  20   b  of the gas damper  20 , the bias force of the gas damper  20  can be imposed on the chair back bottom support member  14   a , so that a protruding amount (length) of the piston rod  20   a  of the gas damper  20  can be changed. When the hand is released from the hand brake  20   b  of the gas damper  20 , the piston rod  20   a  of the gas damper  20  is locked with the protruding amount (length) of that time, and the posture is maintained. 
     Therefore, for example, when the caregiver grips the hand brake  20   b  of the gas damper  20  in the flat posture as shown in  FIG. 2B , lock of the piston rod  20   a  of the gas damper  20  is cancelled, so that the bias force of the gas damper  20  can be imposed on the chair back bottom support member  14   a . Therefore, even when the care-receiver gets on the wheelchair  9  and the back of the care-receiver is supported by the chair back bottom member  15   a  and the chair back bottom support member  14   a , the bias force of the gas damper  20  and the weight of the care-receiver are substantially cancelled out, so that the caregiver can easily perform the posture change. That is, the bias force of the gas damper  20  and the weight of the care-receiver are substantially cancelled out, and the caregiver can change the chair back bottom support member  14   a  from the flat posture to the seating posture and from the seating posture to the flat posture. The strength of the bias force of the gas damper  20  is preferably preliminarily adjusted so as to be cancelled out with the weight of the care-receiver. By imposing the bias force of the gas damper  20  on the chair back bottom support member  14   a  in such a way, for example, when the flat posture is changed to the seating posture, the chair back bottom support member  14   a  can be easily pivoted anticlockwise of  FIG. 2B  about the chair first bending portion  14   j . Then, the chair leg first support member  14   d  is pulled to the chair back bottom support member side via the first coupling link member  14   p , and the chair knee bottom support member  14   c  is pivoted clockwise about the chair second bending portion  14   k  relative to the chair waist bottom portion  15   b . At the same time as this clockwise pivoting, the chair leg first support member  14   d  is pivoted anticlockwise about the chair third bending portion  14   m , and the chair leg second support member  14   e  is pivoted clockwise about the chair fourth bending portion  14   n  via the second coupling link member  14   q . Therefore, as shown in  FIG. 2C , the wheelchair  9  can be changed from the flat posture to the seating posture. 
     Conversely, at the time of performing the posture change from the seating posture to the flat posture, when the caregiver grips the handle  23  with one hand thereof while gripping the hand brake  20   b  with the other hand thereof in the seating posture state of the wheelchair  9 , the lock of the piston rod  20   a  of the gas damper  20  is cancelled, so that the bias force of the gas damper  20  can be imposed on the chair back bottom support member  14   a . At this time, by utilizing the weight of the care-receiver, the chair back bottom support member  14   a  is manually brought downward. That is, the chair back bottom support member  14   a  can be easily and slowly pivoted clockwise of  FIG. 2B  about the chair first bending portion  14   j . Then, the tensile force imposed on the first coupling link member  14   p  is cancelled and loosened, and the chair knee bottom support member  14   c  and the chair leg first support member  14   d  are respectively relatively pivoted about the chair second bending portion  14   k , the chair third bending portion  14   m , and the chair fourth bending portion  14   n  and respectively changed from an obliquely inclined posture to the flat posture, thereby performing the posture change. This posture change is performed by weight of the vicinity of the knees of the care-receiver imposed on the chair knee bottom support member  14   c  via the chair knee bottom member  15   c , and by weight of the legs of the care-receiver imposed on the chair leg first support member  14   d  via the chair leg first bottom member  15   d . That is, the chair knee bottom support member  14   c  is pivoted anticlockwise about the chair second bending portion  14   k , and at the same time, the chair leg first support member  14   d  is pivoted clockwise about the chair third bending portion  14   m , and the chair leg second support member  14   e  is pivoted anticlockwise about the chair fourth bending portion  14   n  via the second coupling link member  14   q . Therefore, the postures of the chair knee bottom support member  14   c  supporting the chair knee bottom member  15   c  of a leg surface part, the chair leg first support member  14   d  supporting the chair leg first bottom member  15   d , and the chair leg second support member  14   e  supporting the chair leg second bottom member  15   e  are changed so as to be close to the flat posture. Further, when the chair back bottom support member  14   a  is brought down until the chair back bottom member  15   a  and the chair waist bottom member  15   b  are in a flat surface, the chair waist bottom member  15   b , the chair knee bottom member  15   c , the chair leg first bottom member  15   d , and the chair leg second bottom member  15   e  are also in one flat surface. The chair back bottom member  15   a , the chair waist bottom member  15   b , the chair knee bottom member  15   c , the chair leg first bottom member  15   d , and the chair leg second bottom member  15   e  are in one continuous flat surface. As shown in  FIG. 2B , the wheelchair  9  is changed from the seating posture to the flat posture. This is because of the link mechanism in which the chair bottom support member  14  supports the seating bottom portion  15 , and in conjunction with inclination of the chair back bottom support member  14   a , the postures of the chair knee bottom support member  14   c , the chair leg first support member  14   d , and the chair leg second support member  14   e  are changed via the first coupling link member  14   p  and the second coupling link member  14   q.    
     The chair leg second support member  14   e  is coupled to the chair knee bottom support member  14   c  via the second coupling link member  14   q . Thus, the chair leg second support member  14   e  is only moved parallel in a vertical direction whether the wheelchair  9  is in the flat posture or the seating posture, and always maintains a position along the horizontal direction. 
     With such a configuration, in the wheelchair  9  of the first embodiment, only by changing inclination of the chair back bottom member  15   a  of the wheelchair  9 , the postures of the chair knee bottom member  15   c , the chair leg first bottom member  15   d , and the chair leg second bottom member  15   e  can be changed in conjunction with the change. That is, only by performing one action by the caregiver, the wheelchair  9  performs the posture change of the back and the legs simultaneously. Thus, the posture change of the wheelchair  9  can be easily and reliably performed although the posture change is manually performed. 
       FIG. 3A  is a perspective view of the bed  11  at the time of the separation in which the seating bottom portion  15  of the wheelchair  9  is in the flat posture in order to combine the wheelchair  9  and the bed main body portion  10 . At this time, the bed bottom portion  17  of the bed main body portion  10  is also in the flat posture. 
     The bed bottom portion  17  has the bed back bottom member  17   a , the bed waist bottom member  17   b , the bed knee bottom member  17   c , and the bed leg bottom member  17   d  bendably coupled to one another. That is, the bed bottom portion  17  is composed of the four bed bottom members  17   a ,  17   b ,  17   c ,  17   d . Among these members, the adjacent members are bendably coupled to each other at three points via the coupling parts of thin parts or hinges. The coupling parts of the thin parts may be composed of parts each having a thickness thinner than a thickness of each of the bed back bottom member  17   a  to the bed leg bottom member  17   d  mainly composing the bed bottom portion  17 , and thereby the coupling parts are bendable. The bed back bottom member  17   a , the bed waist bottom member  17   b , the bed knee bottom member  17   c , and the bed leg bottom member  17   d  are parts to be brought into contact with the back, the waist, the knees, and the legs including the heels of the care-receiver, respectively, and generally have the cushion function. 
     It should be noted that since the seating bottom portion  15  has the five divided members  15   a ,  15   b ,  15   c ,  15   d ,  15   e  and are bent at four points, a division structure is different between the bed bottom portion  17  and the seating bottom portion  15 . However, the three divided members  17   a ,  17   b ,  17   c  of the bed bottom portion  17  respectively correspond to the three divided members  15   a ,  15   b ,  15   c  of the seating bottom portion  15 , and the remaining one divided member  17   d  of the bed bottom portion  17  corresponds to the remaining two divided members  15   d ,  15   e  of the seating bottom portion  15 . 
     As shown in  FIG. 3A , the bed bottom support member  18  is composed of the bed back bottom support member  18   a  composed into a ladder shape in which a large number of crosspieces are fixed in the width direction between a pair of support rod members in the longitudinal direction, the bed knee bottom support member  18   c  composed into a similar ladder shape to the bed back bottom support member  18   a , the bed leg bottom support member  18   d  composed into a similar ladder shape to the bed back bottom support member  18   a , and three bed first to third bending portions  18   j ,  18   k ,  18   m  bendably coupling the adjacent support members to each other. The bed back bottom support member  18   a  always supports the bed back bottom member  17   a , and a protruding portion  118  protruding in the width direction from the bed back bottom member  17   a  is capable of supporting the chair back bottom member  15   a . The bed knee bottom support member  18   c  always supports the bed knee bottom member  17   c , and a protruding portion  118  protruding in the width direction from the bed knee bottom member  17   c  is capable of supporting the chair knee bottom member  15   c . The bed leg bottom support member  18   d  always supports the bed leg bottom member  17   d , and a protruding portion  118  protruding in the width direction from the bed leg bottom member  17   d  is capable of supporting the chair leg first bottom member  15   d  and the chair leg second bottom member  15   e . In such a way, the bed back bottom support member  18   a , the bed knee bottom support member  18   c , and the bed leg bottom support member  18   d  respectively compose the protruding portions  118  respectively exposed to protrude on one side in the width direction from the bed back bottom member  17   a , the bed waist bottom member  17   b , the bed knee bottom member  17   c , and the bed leg bottom member  17   d . These protruding portions  118  are capable of supporting the chair back bottom member  15   a , the chair waist bottom member  15   b , the chair knee bottom member  15   c , the chair leg first bottom member  15   d , and the chair leg second bottom member  15   e  of the wheelchair  9  after the wheelchair  9  is combined with the bed main body portion  10 . 
     That is, the bed back bottom support member  18   a  and the bed waist bottom member  17   b  are bendably coupled to each other by the bed first bending portion  18   j . The bed waist bottom member  17   b  and the bed knee bottom support member  18   c  are bendably coupled by the bed second bending portion  18   k . The bed knee bottom support member  18   c  and the bed leg bottom support member  18   d  are bendably coupled to each other by the bed third bending portion  18   m.    
     Since the bed waist bottom member  17   b , the bed back bottom support member  18   a , and the chair knee bottom support member  18   c  are coupled to one another, the position displacement is not generated between the bed bottom member  17  and the bed bottom support member  18 . 
     In an end on the back surface side of the bed base portion  19  positioned on the lower side of a front end on the back surface side of the bed back bottom support member  18   a  in the flat posture, a first flat posture detection sensor  21  is arranged. By contact with the front end on the back surface side of the bed back bottom support member  18   a  in the flat posture, the first flat posture detection sensor  21  detects that the bed back bottom support member  18   a  is in the flat posture. In an end on the leg side of the bed base portion  19  positioned on the lower side of a front end on the back surface side of the bed leg bottom support member  18   d , a second flat posture detection sensor  22  is arranged. By contact with the front end on the back surface side of the bed leg bottom support member  18   d  in the flat posture, the second flat posture detection sensor  22  detects that the bed leg bottom support member  18   d  is in the flat posture. The first flat posture detection sensor  21  and the second flat posture detection sensor  22  can be, for example, respectively composed of limit switches for respectively detecting the contact of the bed back bottom support member  18   a  in the flat posture and the contact of the bed leg bottom support member  18   d  in the flat posture. Detection information of the first flat posture detection sensor  21  and the second flat posture detection sensor  22  is respectively outputted to a control section  100 , and the control section  100  can respectively determine the flat posture of the bed back bottom support member  18   a  and the flat posture of the bed leg bottom support member  18   d.    
     As shown in  FIG. 1C , the control section  100  is to control actions of a combining method and a separating method of the bed, and to control drive of a drive section or a drive device based on input information from the sensors. 
     A rotatable roller  24  is arranged on the front end of the bed leg bottom support member  18   d . In the back lifting posture and the knee lifting posture, the roller  24  rolls and moves on a flat rail or an interior of a groove of the bed base portion  19 , so that the bed leg bottom support member  18   d  can smoothly perform a bending or bending cancellation action between the knee lifting posture and the flat posture relative to the bed base portion  19 . 
     In the first embodiment, a first electric drive section  41   a  and a second electric drive section  41   b  are further provided so that a back lifting action and a knee lifting action are independently performed on a bed bottom portion  16  composed of integrating the seating bottom portion  15  and the bed bottom portion  17 . 
     The first electric drive section  41   a  can change inclination of the back bottom support member  18   a . The second electric drive section  41   b  can change the postures of the knee bottom support member  18   c  and the leg bottom support member  18   d.    
     An arm  42   a  of a back lifting translation actuator  41   a  serving as one example of the first electric drive section  41   a  is coupled to a front end of a branch coupling portion  18   f  branched on a back surface on the base end side of the bed back bottom support member  18   a  so as to lift or bring down the bed back bottom support member  18   a  via the arm  42   a . Therefore, by driving the back lifting translation actuator  41   a  so as to make the piston rod  42   a  travel back and forth, the bed back bottom support member  18   a  can be pivoted between the seating posture and the flat posture via the first bending portion  18   j  between the bed back bottom support member  18   a  and the bed waist bottom member  17   b.    
     It should be noted that as another example, as shown in  FIGS. 7A and 7B , instead of providing the branch coupling portion  18   f  on the back surface on the base end side of the bed back bottom support member  18   a , a front end of the piston rod  42   a  may be curved toward the base end side of the bed back bottom support member  18   a  so as to be separably bring into contact with the back surface on the base end side of the bed back bottom support member  18   a . In such a way, only when the bed back bottom support member  18   a  stands up, the back lifting translation actuator  41   a  is driven and the back surface on the base end side of the bed back bottom support member  18   a  is pressed by the piston rod  42   a . Meanwhile, when the bed back bottom support member  18   a  is brought down to the flat posture, by not pulling the bed back bottom support member  18   a  by the piston rod  42   a  but only by driving the back lifting translation actuator  41   a  so as to retreat the piston rod  42   a , the bed back bottom support member  18   a  may be brought down with utilizing the weight of the care-receiver. Therefore, in this case, the back surface of the bed back bottom support member  18   a  and the front end of the piston rod  42   a  are simply brought into contact with each other and easily separable for each other, so that a force transmission switching mechanism  90   a  for switching between transmission and blocking of force for a kind of posture change is formed. 
     An arm  42   b  of a knee lifting translation actuator  41   b  serving as one example of the second electric drive section is coupled to a front end of a branch coupling portion  18   g  branched on a back surface on the base end side of the bed knee bottom support member  18   c  so as to lift or bring down the bed knee bottom support member  18   c  via the arm  42   b , so that the bed knee bottom support member  18   c  and the bed leg bottom support member  18   d  are bent into an inverted V shape or made to be a flat surface. Therefore, by driving the knee lifting translation actuator  41   b  so as to extend the piston rod  42   b , the bed knee bottom support member  18   c  is pivoted clockwise about the bed second bending portion  18   k  relative to the bed waist bottom member  17   b , and at the same time, the bed leg bottom support member  18   d  is pivoted anticlockwise about the bed third bending portion  18   m . Thus, as shown in  FIG. 3C , the bed main body portion  10  can be changed from the flat posture to the back lifting posture and the knee lifting posture. Conversely, by driving the knee lifting translation actuator  41   b  so as to contract the piston rod  42   a , the bed knee bottom support member  18   c  is pivoted anticlockwise about the bed second bending portion  18   k  relative to the bed waist bottom member  17   b , and at the same time, the bed leg bottom support member  18   d  is pivoted clockwise about the bed third bending portion  18   m . Therefore, as shown in  FIG. 3B , the bed main body portion  10  can be changed from the back lifting posture and the knee lifting posture to the flat posture. 
     It should be noted that as another example, as shown in  FIGS. 7A and 7B , instead of providing the branch coupling portion  18   g  on the back surface on the base end side (the side of the leg bottom support member  18   d ) of the bed knee bottom support member  18   c , a front end of the piston rod  42   b  may be curved toward the base end side of the bed knee bottom support member  18   c  so as to be separably brought into contact with the back surface on the base end side of the bed knee bottom support member  18   c . In such a way, only when the bed knee bottom support member  18   c  stands up, the back lifting translation actuator  41   b  is driven and the back surface on the base end side of the bed knee bottom support member  18   c  is pressed by the piston rod  42   b . Meanwhile, when the bed knee bottom support member  18   c  is brought down to the flat posture, by not pulling the bed knee bottom support member  18   c  by the piston rod  42   b  but only by driving the back lifting translation actuator  41   b  so as to retreat the piston rod  42   b , the bed knee bottom support member  18   c  may be brought down with utilizing the weight of the care-receiver. Therefore, in this case, the back surface of the bed knee bottom support member  18   c  and the front end of the piston rod  42   b  are simply brought into contact with each other and easily separable for each other, so that a force transmission switching mechanism  90   b  for switching between the transmission and the blocking of the force for a kind of posture change is formed. 
     The back lifting translation actuator  41   a  and the knee lifting translation actuator  41   b  are respectively independently driven. Thus, a back lifting action/back lowering action and a knee lifting action/knee lowering action can be independently performed. By respectively operating the back lifting translation actuator  41   a  and the knee lifting translation actuator  41   b  by an operating remote controller  61  as described later, the care-receiver can autonomously perform the back lifting action and the knee lifting action from his/her own motive. 
     On one of left and right sides in the width direction of the bed bottom portion  17  (for example, on the left side in  FIG. 3A ), the recess portion  28  serving as the combination area is formed as a space into which the chair base portion is inserted between the bed back bottom support member  18   a  and the bed knee bottom support member  18   c , so that the chair base portion  13  of the wheelchair  9  is insertable into the recess portion  28 . 
     The elevating section  27  functioning as one example of an elevating machine of the bed main body portion  10  is a part of the members composing the bed main body portion  10 , is arranged between the bed bottom support member  18  and the bed base portion  19 , and is provided with a link mechanism extendable and contractible in the vertical direction so as to move the entire bed bottom support member  18  parallel in the vertical direction, and an elevating motor  27   m  coupled to a link of the link mechanism so as to extend and contract the link mechanism by forward/backward rotation of a rotation shaft. As a mechanism for coupling the rotation shaft of the elevating motor  27   m  to the link of the link mechanism so as to move the link mechanism up and down, for example, a mechanism in which a ball screw is rotated by the rotation shaft so as to make a nut member screwed to the ball screw travel back and forth in the axial direction and this linear motion is converted into a vertical motion by a pantagraph type link mechanism, or the like can be adopted. Although the bed waist bottom member  17   b  is fixed to the bed base portion  19  via the elevating section  27 , the bed bottom support members  18   a ,  18   c ,  18   d  are supported bendably relative to the elevating section  27  (movably in the longitudinal direction relative to the elevating section  27  and partially separably in the vertical direction). Under control of the control section  100 , the elevating motor  27   m  of the elevating section  27  is driven and the rotation shaft thereof is rotated forward and backward so as to extend and contract the elevating section  27  in the vertical direction, and the bed bottom support member  18  supported on the elevating section  27  can be moved parallel in the vertical direction between an upper end position for a combination action and a lower end position for a separation action, and within a bed elevating range d after the combination. A lowest end position of the bed elevating range d is the upper end position for the combination action. When the bed bottom support member  18  is positioned at the upper end position for the combination action, the bed bottom support member  18  is brought into contact with the seating bottom portion  15  of the chair  9  and the seating bottom portion  15  is brought up by the bed bottom support member  18 . Thus, the seating bottom portion  15  is away from the chair bottom support member  14 . Since the seating bottom portion  15  is away from the chair bottom support member  14 , the seating bottom portion  15  of the chair  9  is supported only by the bed bottom support member  18  instead of the chair bottom support member  14 . Meanwhile, when the bed bottom support member  18  is positioned at the lower end position for the separation action, the chair bottom support member  14  is brought into contact with the seating bottom portion  15  of the chair  9  and the seating bottom portion  15  is brought up by the chair bottom support member  14 . Since the seating bottom portion  15  is brought up by the chair bottom support member  14 , the seating bottom portion  15  is away from the bed bottom support member  18 , and the seating bottom portion  15  is supported only by the chair bottom support member  14  instead of the bed bottom support member  18 . By such an elevating action of the elevating section  27 , the posture change mechanism of the seating bottom portion  15  can be switched between the chair bottom support member  14  and the bed bottom support member  18  by the support switching mechanism. 
     As shown in  FIG. 4A , a contact detection sensor  45  serving as one example of a contact detection means for detecting that the bed bottom support member  18  supports the seating bottom portion  15  is provided in the bed bottom support member  18 . Detection information of the contact detection sensor  45  is outputted to the control section  100 . Therefore, based on the detection information of the contact detection sensor  45 , the control section  100  can determine whether or not the bed bottom support member  18  supports the seating bottom portion  15 . 
       FIG. 9  is a view showing an operating surface of the operating remote controller  61 . The operating remote controller  61  has an elevating button  62 , a back lifting and lowering button  63 , a knee lifting and lowering button  64 , a combining button  66 , and a separating button  67 . The operating remote controller  61  is connected to the control section  100  of the bed main body portion  10  by a communication cord or wirelessly, and provides an operating instruction to the control section  100  so as to drive the back lifting translation actuator  41   a , the knee lifting translation actuator  41   b , and the elevating motor  27   m  of the elevating section  27 . The operating remote controller is provided with a speaker for audibly notifying of various information. 
     The elevating button  62  is a switch for driving the elevating motor  27   m  of the elevating section  27 , and changes height of the bed bottom portion  16  of the bed  11  after completion of the combination, in the vertical direction within the bed elevating range d. That is, the elevating button  62  is to perform operations of raising and lowering the bed bottom portion  16  within the bed elevating range d shown in  FIG. 4B  serving as a high range which is a position where the bed bottom support member  18  is brought into contact with the seating bottom portion  15  or more. 
     The back lifting and lowering button  63  is a switch for driving the back lifting translation actuator  41   a , and performs the back lifting action or the back lowering action of the bed  11 . 
     The knee lifting and lowering button  64  is a switch for driving the knee lifting translation actuator  41   b , and performs the knee lifting action or the knee lowering action of the bed  11 . 
     The combining button  66  is a switch for driving the elevating motor  27   m  of the elevating section  27  so as to combine the separated bed  11  (that is, to combine the wheelchair  9  and the bed main body portion  10 ), and raises the bed bottom support member  18  to the upper end position for the combination action by drive of the elevating motor  27   m  while the combining button  66  is being pressed. 
     The separating button  67  is a switch for driving the elevating motor  27   m  of the elevating section  27  so as to separate the combined bed  11 , and lowers the bed bottom support member  18  to the lower end position for the separation action by the drive of the elevating motor  27   m  while the separating button  67  is being pressed. By pressing only the separating button  67 , the elevating motor  27   m , the back lifting translation actuator  41   a , and the knee lifting translation actuator  41   b  may be driven, so that the bed  11  performs the back lowering action, the knee lowering action, and a lowering action so as to be changed to the flat posture, and the bed bottom portion  16  is lowered from the upper end position for the combination action to the lower end position for the separation action so as to become a state of capable of performing the separation action. 
     A positioning sensor  51  is provided in the bed base portion  19  in an innermost part of the recess portion  28  serving as the combination area, so as to detect that the chair base portion  13  is moved to and rightly positioned in the recess portion  28 . As one example, the positioning sensor  51  is composed of a limit switch to be brought into contact with the chair base portion  13  when the chair base portion  13  is rightly positioned in the recess portion  28 . Detection information of the positioning sensor  51  is outputted to the control section  100 . Therefore, when the chair base portion  13  is not rightly positioned in the recess portion  28 , the positioning sensor  51  cannot detect, and the control section  100  can determine that the chair base portion  13  is not rightly positioned in the recess portion  28 . 
     A locking portion  40  for coupling and fixing the seating bottom portion  15  and the bed bottom portion  17  with a locking member (not shown) or canceling the coupling by manually pivoting a coupling lever  39  between a lock position and a lock cancellation position is provided in the bed base portion  19 . When the seating bottom portion  15  and the bed bottom portion  17  are coupled and fixed by this locking portion  40 , the seating bottom portion  15  and the bed bottom portion  17  are integrated so as to compose the bed bottom portion  16 . The height of the bed bottom portion  16  at this time is the lowest state as the bed  11  at the time of the combination. 
     A lock sensor  43  for detecting whether or not the seating bottom portion  15  and the bed bottom portion  17  are locked by the locking portion  40  is provided in the bed base portion  19 . The lock sensor  43  is, for example, composed of a limit switch or a proximity switch for detecting movement of the locking member when the seating bottom portion  15  and the bed bottom portion  17  are locked by the locking member of the locking portion  40 . Detection information of the lock sensor  43  is respectively outputted to the control section  100 , and the control section  100  determines whether or not the locking portion  40  provides lock. Based on the detection information of the lock sensor  43 , when the control section  100  determines that the locking portion  40  provides the lock (a lock state), the control section  100  activates the elevating button  62 , the back lifting and lowering button  63 , and the knee lifting and lowering button  64  of the operating remote controller  61 . Conversely, based on the detection information of the lock sensor  43 , when the control section  100  determines that the locking portion  40  does not provide the lock (a non-lock state), the control section  100  deactivates the elevating button  62 , the back lifting and lowering button  63 , and the knee lifting and lowering button  64  of the operating remote controller  61 . 
     With using the above configuration, in order to combine the wheelchair  9  and the bed main body portion  10 , the wheelchair  9  in the flat posture is brought close to the bed main body portion  10  in the flat posture along the width direction of the bed main body portion  10  (refer to  FIG. 2A ). The chair base portion  13  of the wheelchair  9  is moved to and positioned in the recess portion  28  serving as the combination area provided on the side of the bed waist bottom member  17   b  between the bed back bottom support member  18   a  and the bed knee bottom support member  18   c . At this time, the positioning sensor  51  provided in the bed base portion  19  in the innermost part of the recess portion  28  detects that the chair base portion  13  is moved to and rightly positioned in the recess portion  28 , and the control section  100  determines that the chair base portion  13  is rightly positioned in the recess portion  28 . When the chair base portion  13  is moved to and positioned in the recess portion  28 , the seating bottom portion  15  and the bed bottom portion  17  are arranged side by side. 
     The chair base portion  13  is moved into the recess portion  28 , the chair base portion  13  is positioned in the recess portion  28 , and based on the information from the positioning sensor  51 , the control section  100  determines that the chair base portion  13  is rightly positioned in the recess portion  28 , and thereafter the bed  11  performs a switching action of the posture change mechanism by the support switching mechanism. Firstly, the elevating motor  27   m  of the elevating section  27  of the bed main body portion  10  is driven under the control of the control section  100  so as to raise the bed bottom support member  18  supported by the elevating section  27 , so that height of the bed bottom support member  18  of the bed main body portion  10  is increased to the upper end position for the combination action. Then, the support member supporting the seating bottom portion  15  is switched from the chair bottom support member  14  to the bed bottom support member  18  by the support switching mechanism. That is, from a state where the seating bottom portion  15  is supported only by the chair bottom support member  14  through a state where the seating bottom portion  15  is supported by the chair bottom support member  14  and the bed bottom support member  18 , when the bed bottom support member  18  is raised to the upper end position for the combination action, the seating bottom portion  15  is supported only by the bed bottom support member  18 . As a result, the support member supporting the seating bottom portion  15  is switched from the chair bottom support member  14  to the bed bottom support member  18  by the support switching mechanism. The contact detection sensor  45  detects that the bed bottom support member  18  is raised to the upper end position for the combination action. 
       FIGS. 4A and 4B  are front views in which the bed  11  during a switching action of the posture change mechanism is seen from the front side.  FIG. 4A  is a front view of a state where the seating bottom portion  15  is supported only by the chair bottom support member  14 .  FIG. 4B  is a front view of a state where the seating bottom portion  15  is supported only by the bed bottom support member  18 . With using  FIGS. 4A and 4B , switching of a point supporting the seating bottom portion  15  from the chair bottom support member  14  to the bed bottom support member  18  by the support switching mechanism will be described in detail. 
     Firstly, when the wheelchair  9  and the bed main body portion  10  start the switching action of the posture change mechanism by the support switching mechanism, the posture change mechanism of the seating bottom portion  15  is switched from the chair bottom support member  14  to the bed bottom support member  18 . In other words, the seating bottom portion  15  is disposed only on the bed bottom support member  18  and supported by the bed bottom support member  18 . At this time, the seating bottom portion  15  is put on the protruding portions  118  of the bed bottom support member  18  protruding from the bed bottom portion  17  toward the side of the wheelchair  9  in the horizontal direction and supported by the protruding portions  118 . A lower surface of the seating bottom portion  15  is supported by the protruding portions  118  of the bed bottom support member  18  in such a manner that the seating bottom portion  15  and the bed bottom portion  17  are integrated so as to compose the bed bottom portion  16 . Parts of the bed bottom support member  18  other than the protruding portions  118  support a lower surface of the bed bottom portion  17 . 
     Describing this based on the figures, firstly, as shown in  FIG. 4A  before switching, in a state where the seating bottom portion  15  is supported only by the chair bottom support member  14 , the bed bottom support member  18  is placed under the seating bottom portion  15 . At this time, the bed bottom portion  17  is lower than the seating bottom portion  15 , and an upper surface of the bed bottom support member  18  supporting the bed bottom portion  17  is lower than an upper surface of the chair bottom support member  14  supporting the seating bottom portion  15 . Therefore, the protruding portions  118  of the bed bottom support member  18  and the seating bottom portion  15  are away from each other, and the protruding portions  118  of the bed bottom support member  18  do not support the seating bottom portion  15 . 
     By pressing the combining button  66 , the elevating section  27  is driven under the control of the control section  100 , so that the bed bottom support member  18  is raised from the lower end position for the separation action to the upper end position for the combination action. By raising the protruding portions  118  of the bed bottom support member  18  to a point where the protruding portions  118  are brought into contact with the seating bottom portion  15  (the upper end position for the combination action) as shown in  FIG. 4B , the seating bottom portion  15  is supported by the protruding portions  118  of the bed bottom support member  18 . 
     In such a way, the bed base portion  19  can raise and lower the bed bottom support member  18  between the upper end position for the combination action and the lower end position for the separation action by the elevating section  27  under the control of the control section  100 . When the wheelchair  9  and the bed main body portion  10  start the switching action of the posture change mechanism by the support switching mechanism, the bed bottom support member  18  is raised by the elevating section  27  under the control of the control section  100 , so that the bed bottom support member  18  placed under the seating bottom portion  15  is brought into contact with the lower surface of the seating bottom portion  15 . Since the seating bottom portion  15  is brought into contact with the bed bottom support member  18  and supported by the bed bottom support member  18 , the seating bottom portion  15  performs the posture change following the bed bottom support member  18 . At this time, the seating bottom portion  15  does not follow an action of the chair bottom support member  14  and not perform the posture change by the chair bottom support member  14 . 
     After that, by fixing the seating bottom portion  15  and the bed bottom support member  18  by the locking portion  40 , the seating bottom portion  15  and the bed bottom portion  17  are integrated so as to compose the bed bottom portion  16 . At this time, the height of the bed bottom portion  16  is the lowest state as the bed  11  at the time of the combination. In other words, the bed bottom portion  16  is at the lowest end of the bed elevating range d within which the bed  11  at the time of the combination can be moved up and down by actuating the elevating section  27 . At this time, all the four traveling wheels  12  of the wheelchair  9  are in contact with the ground (or the installment surface of the wheelchair  9  and the bed main body portion  10 )  44 . In the bed  11  in which the wheelchair  9  and the bed main body portion  10  are combined, the seating bottom portion  15  and the bed bottom portion  17  can integrally perform the posture change as the nursing care bed. By actuating the elevating section  27  under the control of the control section  100 , the height of the bed bottom portion  16  can be increased. In the case where by actuating the elevating section  27  under the control of the control section  100 , the bed bottom portion  16  is raised within the bed elevating range d from a state where the bed bottom portion  16  shown in  FIG. 4B  is in the lowest end, all the traveling wheels  12  of the wheelchair  9  are brought up and are away from the ground (or the installment surface of the wheelchair  9  and the bed main body portion  10 )  44 . 
     It should be noted that in the case where a state where the seating bottom portion  15  is supported only by the protruding portions  118  of the bed bottom support member  18  shown in  FIG. 4B  is switched to a state where the seating bottom portion  15  is supported only by the chair bottom support member  14  shown in  FIG. 4A  by the support switching mechanism, by pressing the separating button  67 , the height of the bed bottom support member  18  is decreased by the elevating section  27  under the control of the control section  100 , so that the support member supporting the seating bottom portion  15  is switched from support only by the bed bottom support member  18  to support only by the chair bottom support member  14 . 
       FIG. 5  is a perspective view of the bed  11  at the time of the combination in the flat posture. In the bed  11 , the wheelchair  9  in the flat posture is combined with the bed main body portion  10  in the flat posture. Therefore, without getting out of the wheelchair  9 , the care-receiver can get on the bed  11  while being in the wheelchair  9 . Therefore, a physical burden on the caregiver can be reduced. 
     In the combined bed  11 , the bed bottom portion  17  and the seating bottom portion  15  are integrated so as to form one flat bed bottom portion  16 , and the posture change can be performed only by the bed bottom support member  18 . The flat posture shown in  FIG. 5  is changed to the back lifting posture by integrally lifting the chair back bottom member  15   a  and the bed back bottom member  17   a  by the back bottom support member  18   a . The chair waist bottom member  15   b  and the bed waist bottom member  17   b  serve as one block. Further, the chair knee bottom member  15   c  and the bed knee bottom member  17   c  serve as one block, and the chair leg first bottom member  15   d , the chair leg second bottom member  15   e , and the bed leg bottom member  17   d  serve as one block. The knee lifting posture in which the two blocks are bent into an inverted V shape is composed of the knee bottom support member  18   c  and the leg bottom support member  18   d.    
       FIG. 6  is a perspective view of the bed  11  in back lifting posture and knee lifting posture states.  FIGS. 7A and 7B  are side views of the bed  11  in the back lifting posture and knee lifting posture states and in the bed lowering state and the bed raising state. 
     As shown in  FIGS. 6, 7A, and 7B , the bed bottom portion  16  composed of the seating bottom portion  15  and the bed bottom portion  17  is made by coupling the plurality of divided members  15   a ,  15   b ,  15   c ,  15   d ,  17   a ,  17   b ,  17   c ,  17   d  so that the back lifting posture and the knee lifting posture can be formed. By lifting the back bottom support member  18   a  as a part of the bed bottom support member  18  and lifting and bending the knee bottom support member  18   c  and the leg bottom support member  18   d  as a part of the bed bottom support member  18  into an inverted V shape, the back lifting action and the knee lifting action as well as those with a general nursing care bed can be performed. At this time, by moving the coupling lever  39  so as to couple the seating bottom portion  15  and the bed bottom portion  17  by the locking portion  40 , the seating bottom portion  15  and the bed bottom portion  17  are not displaced from each other. 
     When the wheelchair  9  and the bed main body portion  10  are combined, the posture change mechanism of the seating bottom portion  15  of the wheelchair  9  is switched from the chair bottom support member  14  to the bed bottom support member  18  by the support switching mechanism. Therefore, in the case where electric drive control is performed as the bed  11 , there is no need for providing electric drive sections in the wheelchair  9 . Even when there are no electric drive sections in the wheelchair  9 , the bed  11  can be electrically driven. As a result, the wheelchair  9  can be simplified and weight thereof can be reduced. 
     When the knee bottom support member  18   c  and the leg bottom support member  18   d  are bent into an inverted V shape as shown in  FIGS. 6, 7A, and 7B , the chair knee bottom member  15   c  and the chair leg first bottom member  15   d  are bent into an inverted V shape, and the bed knee bottom member  17   c  and the bed leg bottom member  17   d  are bent into an inverted V shape. Then, knee lifting is performed in the bed bottom portion  16 . When the knee bottom support member  18   c  and the leg bottom support member  18   d  are in a flat surface, the chair knee bottom member  15   c , the chair leg first bottom member  15   d , the chair leg second bottom member  15   e , the bed knee bottom member  17   c , and the bed leg bottom member  17   d  are also in a flat surface. 
     It should be noted that in the longitudinal direction of the bed bottom portion  16 , longitudinal dimension of the chair back bottom member  15   a  is equal to longitudinal dimension of the bed back bottom member  17   a , longitudinal dimension of the chair waist bottom member  15   b  is equal to longitudinal dimension of the bed waist bottom member  17   b , longitudinal dimension of the chair knee bottom member  15   c  is equal to longitudinal dimension of the bed knee bottom member  17   c , and a total dimension of a longitudinal dimension of the chair leg first bottom member  15   d  and a longitudinal dimension of the chair leg second bottom member  15   e  is equal to a longitudinal dimension of the bed leg bottom member  17   d . This is because the length is equalized so that the bed bottom portion  17  and the seating bottom portion  15  can integrally perform the posture change. In the width direction of the bed bottom portion  16 , a total dimension of a width dimension of the chair back bottom member  15   a  and a width dimension of the bed back bottom member  17   a , a total dimension of a width dimension of the chair waist bottom member  15   b  and a width dimension of the bed waist bottom member  17   b , a total dimension of a width dimension of the chair knee bottom member  15   c  and a width dimension of the bed knee bottom member  17   c , and a total dimension of a width dimension of the chair leg first bottom member  15   d  or a width dimension of the chair leg second bottom member  15   e  and the bed leg bottom member  17   d  are equal to each other. This is to make the members have the same width dimension as the bed bottom portion  16  so as to be treated as one bed surface. 
     Next, the combining method of the separated bed will be described. 
       FIG. 8  is a flowchart of the combining method of the bed  11 . As shown in  FIG. 8 , in the combining method of the bed  11 , firstly, positioning step S 01  of detecting that the wheelchair  9  in the flat posture is moved to and rightly positioned in the recess portion  28  serving as the combination area of the bed main body portion  10 . 
     In this positioning step S 01 , the caregiver manually moves the chair base portion  13  of the wheelchair  9  into the recess portion  28  of the bed main body portion  10 . Thereafter, based on the detection information from the positioning sensor  51 , the control section  100  determines whether or not the chair base portion is rightly positioned in the recess portion  28 . When the control section  100  determines that the chair base portion  13  of the wheelchair  9  is rightly positioned in the recess portion  28  based on the detection information from the positioning sensor  51 , the flow proceeds to combination switching step S 02 . When positioning of the wheelchair  9  is completed, the combining button  66  of the operating remote controller  61  shown in  FIG. 9  is lit, and control by the combining button  66  is activated. Further, at this time, from the operating remote controller  61 , the caregiver or the care-receiver can be audibly instructed to press the combining button  66  of the operating remote controller  61 . 
     In the combination switching step S 02 , the posture change mechanism of the seating bottom portion  15  of the wheelchair  9  is switched from the chair bottom support member  14  provided in the wheelchair  9  to the bed bottom support member  18  provided in the bed main body portion  10  by the support switching mechanism. That is, switching of the posture change mechanism of the seating bottom portion  15  by the support switching mechanism indicates that by pressing the combining button  66 , the bed bottom support member  18  is raised by driving the elevating section  27  via the control section  100 , so that support of the seating bottom portion  15  is switched from the chair bottom support member  14  to the bed bottom support member  18 . That is, when the caregiver or the care-receiver presses the combining button  66  of the operating remote controller  61 , firstly, the elevating motor  27   m  of the elevating section  27  is driven and the bed bottom support member  18  is raised only while the combining button  66  is being pressed. When the bed bottom support member  18  comes to height where the bed bottom support member  18  is brought into contact with the lower surface of the seating bottom portion  15  (the upper end position for the combination action), in other words, when the contact detection sensor  45  detects that the bed bottom support member  18  supports the seating bottom portion  15 , the control section  100  stops the elevating motor  27   m , so that a raising action of the bed bottom support member  18  is stopped. Then, the seating bottom portion  15  is supported only by the bed bottom support member  18  from the lower side. Regarding the combining button  66 , the bed bottom portion  16  is raised only while the combining button  66  is being pressed in consideration with safety. However, the bed bottom support member  18  may be automatically moved to the height where the bed bottom support member  18  is brought into contact with the lower surface of the seating bottom portion  15  once the combining button  66  is pressed. When the contact detection sensor  45  detects that the bed bottom support member  18  supports the seating bottom portion  15 , the light of the combining button  66  is turned off. At this time, from the operating remote controller  61 , the caregiver or the care-receiver can be audibly instructed to move the coupling lever  39 . By moving the coupling lever  39 , the seating bottom portion  15  and the bed bottom portion  17  are coupled to each other by the locking portion  40 . 
     Further, after the combination switching step S 02 , bed bottom portion composing step S 03  in which the caregiver or the care-receiver moves the coupling lever  39 , and combines the seating bottom portion  15  and the bed bottom portion  17  of the bed main body portion  10  by the locking portion  40  so as to compose the bed bottom portion  16  is performed. 
     In such a way, by switching the posture change mechanism for performing the posture change of the seating bottom portion  15  by the support switching mechanism after positioning, the bed bottom support member  18  can support the seating bottom portion  15  without the position displacement. 
     Further, in the bed bottom portion composing step S 03 , the bed bottom portion  16  is composed, the lock sensor  43  detects that the locking portion  40  provides the lock, and the control section  100  determines that the locking portion  40  is in the lock state. After that, operations of the elevating button  62 , the back lifting and lowering button  63 , and the knee lifting and lowering button  64  of the operating remote controller  61  are activated by the control section  100 , so that an instruction of performing the posture change by the bed bottom support member  18  can be provided by using the back lifting and lowering button  63  and the knee lifting and lowering button  64  of the operating remote controller  61 . That is, controlling of the back lifting translation actuator  41   a  for driving the back bottom support member  18   a  and the knee lifting translation actuator  41   b  for driving the leg bottom support member  18   d  by the operating remote controller  61  is activated by the control section  100 . By such a combining method, the wheelchair  9  and the bed main body portion  10  are combined. 
     In such a way, after completion of the switching action of the posture change mechanism by the support switching mechanism, the controlling of the back lifting translation actuator  41   a  and the knee lifting translation actuator  41   b  by the operating remote controller  61  is activated by the control section  100 . Thus, during the switching action of the posture change mechanism, failure of the switching action of the posture change mechanism due to an erroneous operation of the operating remote controller  61  can be prevented. If the back lifting and lowering button  63  or the knee lifting and lowering button  64  of the operating remote controller  61  is touched by mistake during the switching action of the posture change mechanism, the bed bottom support member  18  is moved, so that unanticipated posture change is performed. Then, an operator (the caregiver or the care-receiver) becomes incapable of controlling. In order to prevent such a situation, the buttons of the operating remote controller  61  may be preferably controlled by the above control section  100 . 
     Next, the separating method of the bed  11 , which is a method for separating the wheelchair  9  and the bed main body portion  10  will be described. 
       FIG. 10  is a flowchart of the separating method of the bed  11 . The separating method of the bed  11  has flat posture step S 11  of bringing the bed bottom portion  16  of the bed  11  into the flat posture, bed canceling step S 12  of canceling the locking portion  40  combining the seating bottom portion  15  and the bed bottom portion  17  relative to the seating bottom portion  15  and the bed bottom portion  17  composing the bed bottom portion  16  after the flat posture step S 11 , and separation switching step S 13  of switching the point supporting the seating bottom portion  15  from the bed bottom support member  18  to the chair bottom support member  14  after the bed canceling step S 12 . 
     In such a way, by switching the point supporting the seating bottom portion  15  (in other words, the posture change mechanism) from the bed bottom support member  18  to the chair bottom support member  14  by the support switching mechanism after canceling the locking portion  40 , safe separation can be performed. 
     Hereinafter, the separating method of the bed  11  will be described in detail. 
     Firstly, in the flat posture step S 11 , the back lifting and lowering button  63  and the knee lifting and lowering button  64  of the operating remote controller  61  are operated, so that the bed  11  at the time of the combination in the back lifting posture and the knee lifting posture is changed to the flat posture, and the elevating button  62  of the operating remote controller  61  is operated, so that the raised bed bottom portion  16  is lowered to the lowest end of the bed elevating range d. In a state where the bed bottom portion  16  is lowered to the lowest end of the bed elevating range d (in other words, in a state where the bed bottom portion is at the upper end position for the combination action), the back lifting and lowering button  63 , the knee lifting and lowering button  64 , and the separating button  67  of the operating remote controller  61  shown in  FIG. 9  are respectively pressed, the bed  11  respectively performs the back lowering action, the knee lowering action, and the lowering action only while the back lifting and lowering button  63 , the knee lifting and lowering button  64 , and the separating button  67  are respectively being pressed. When the bed is changed to the flat posture and the bed bottom portion  16  is lowered from the upper end position for the combination action to the lower end position for the separation action, the control section  100  stops the action (step S 11 ). It should be noted that instead of respectively pressing the back lifting and lowering button  63 , the knee lifting and lowering button  64 , and the separating button  67 , by pressing only the separating button  67 , the bed  11  may respectively perform the back lowering action, the knee lowering action, and the lowering action so as to be changed to the flat posture, and the bed bottom portion  16  may be lowered from the upper end position for the combination action to the lower end position for the separation action. The control section  100  can determine that the bed is changed to the flat posture based on the detection information from the first flat posture detection sensor  21  and the second flat posture detection sensor  22 . The control section  100  can determine that the bed bottom portion  16  is lowered to the lower end position for the separation action based on detection information from a bed lower limit sensor  95  provided in the bed base portion  19 . 
     When the back lifting and lowering button  63 , the knee lifting and lowering button  64 , and the separating button  67  are respectively pressed, so that the bed  11  is changed to the flat posture and the bed bottom portion  16  is moved to the lowest end of the bed elevating range d (in other words, the upper end position for the combination action), under the control of the control section  100 , the operating remote controller  61  audibly notifies the caregiver or the care-receiver to move the coupling lever  39  so as to cancel the coupling of the locking portion  40 . 
     The caregiver or the care-receiver manually moves the coupling lever  39  so as to cancel the coupling of the locking portion  40  coupling the seating bottom portion  15  and the bed bottom portion  17  (step S 12 ). At this time, the lock sensor  43  detects that the locking portion  40  is cancelled, the detection information of the lock sensor  43  is inputted to the control section  100 , and the control section  100  determines that the locking portion  40  is in the non-lock state. 
     Next, the caregiver presses the separating button  67  of the operating remote controller  61 . At this time, the lock sensor  43  detects that the locking portion  40  is cancelled, and the control section  100  already determines that the locking portion  40  is in the non-lock state. Therefore, by pressing the separating button  67 , the elevating section  27  is lowered, so that the bed bottom support member  18  is brought down to the lower side from the upper end position for the combination action to the lower end position for the separation action. From a state where the bed bottom support member  18  supports the seating bottom portion  15 , the bed bottom support member  18  is brought downward away from the seating bottom portion  15 . Then, the seating bottom portion  15  is supported only by the chair bottom support member  14 . The operating remote controller  61  audibly notifies the caregiver that the wheelchair  9  can be separated from the bed main body portion  10  (step S 13 ). It should be noted that when the control section  100  determines that the locking portion  40  is not cancelled (the locking portion  40  is in the lock state) from a detection result of the lock sensor  43 , the control section  100  can also audibly notify the caregiver or the like to move the coupling lever  39  so as to cancel the coupling of the locking portion  40  from the speaker provided in the operating remote controller  61 . 
     In such a way, by lowering the bed bottom support member  18  by the elevating section  27 , the support of the seating bottom portion  15  is switched from the bed bottom support member  18  to the chair bottom support member  14  by the support switching mechanism. The caregiver manually pulls out the wheelchair  9  from the bed main body portion  10 , and manually brings the wheelchair  9  into the seating posture. By such a separating method, the bed  11  can be separated. 
     It should be noted that in the bed canceling step S 12 , the operations by the operating remote controller  61  for providing the instructions to perform the posture change to the back lifting translation actuator  41   a  and the knee lifting translation actuator  41   b  of the bed bottom support member  18  may be deactivated. In such a way, during a separation operation, failure of the separation due to an erroneous operation of the operating remote controller  61  can be prevented. 
     Second Embodiment 
       FIGS. 11A and 11B  are schematic perspective views of a bed  71  in a second embodiment of the present invention.  FIG. 11A  is a schematic perspective view at the time of the separation.  FIG. 11B  is a schematic perspective view at the time of the combination. 
     The bed  71  of the second embodiment is an electric nursing care bed in which the posture change is performed by the electric drive sections. A wheelchair  72  separated from the bed  71  is an electric reclining wheelchair in which the posture change is performed by electric drive sections. Description of similar configurations and functions to the first embodiment will be omitted, and only different points will be described below. 
     As shown in  FIGS. 11A and 11B , the wheelchair  72  has a first chair electric drive section  74   a , a second chair electric drive section  74   b , and a third chair electric drive section  74   c  so as to respectively independently perform the back lifting action and the back lowering action, the knee lifting action and the knee lowering action, and a leg lifting action and a leg lowering action. 
     The first chair electric drive section  74   a  is arranged in a chair bottom support member  73  of the wheelchair  72 , and driven under the control of the control section  100  so as to change the inclination of the chair back bottom member  15   a.    
     The second chair electric drive section  74   b  is arranged in the chair bottom support member  73  of the wheelchair  72 , and driven under the control of the control section  100  so as to change inclination of the chair knee bottom member  15   c.    
     The third chair electric drive section  74   c  is arranged in the chair bottom support member  73  of the wheelchair  72 , and driven under the control of the control section  100  so as to change inclinations of the chair leg first bottom member  15   d  and the chair leg second bottom member  15   e.    
     The electric drive sections can be formed, for example, by translation actuators as well as those in the first embodiment. 
     By operating the first chair electric drive section  74   a , the second chair electric drive section  74   b , and the third chair electric drive section  74   c  by an operating remote controller  79  exclusive for the wheelchair and driving the electric drive sections under the control of the control section  100 , the care-receiver can perform the back lifting action and the back lowering action, the knee lifting action and the knee lowering action, and the leg lifting action and the leg lowering action from his/her own motive. 
     In the bed  71 , the posture change of the chair bottom support member  73  is realized by the first chair electric drive section  74   a , the second chair electric drive section  74   b , and the third chair electric drive section  74   c  via a freewheel structure which is frequently adopted in a general electric nursing care bed. Thus, the posture change of the seating bottom portion  15  can be switched from the chair bottom support member  73  provided in the wheelchair  72  to the bed bottom support member  18  provided in the bed main body portion  10  by the support switching mechanism. The freewheel structure indicates a structure in which an electrically actuated drive section does not provide restriction. As a specific example of the freewheel structure, the chair back bottom member  15   a  or the bed back bottom member  17   a  is not inseparably coupled to drive sections such as translation actuators, but arms driven by drive sections such as translation actuators to travel back and forth are separably brought into contact with a back surface of the chair back bottom member  15   a  or a back surface of the bed back bottom member  17   a  (for example, refer to a relationship between the arm  42   a  and the bed back bottom support member  18   a  or to a relationship between the arm  42   b  and the bed knee bottom support member  18   c  in  FIG. 7A ). By pressing the chair back bottom member  15   a  or the bed back bottom member  17   a  by the arm, the chair back bottom member  15   a  or the bed back bottom member  17   a  is changed from the flat posture to the seating posture. Meanwhile, by pulling the arm, the chair back bottom member  15   a  or the bed back bottom member  17   a  is changed from the seating posture to the flat posture by utilizing self-weight of the chair back bottom member  15   a  or the bed back bottom member  17   a . The freewheel structure indicates such a structure. This freewheel structure can function as a force transmission switching mechanism for switching between the transmission and the blocking of the force for the posture change relative to the chair bottom support member  73 . 
     In the case where the wheelchair  72  and the bed main body portion  10  are separated from each other, the first chair electric drive section  74   a , the second chair electric drive section  74   b , and the third chair electric drive section  74   c  are actuated so as to change the chair bottom support member  73  to an arbitrary posture. Here, the chair bottom support member  73  is a similar member to the chair bottom support member  14  of the first embodiment. However, a different point from the chair bottom support member  14  is that the chair bottom support member  73  can form the back lifting posture and the knee lifting posture integrally with the seating bottom portion  15  and the bed bottom portion  17  after the combination. 
     In the case where the wheelchair  72  and the bed main body portion  10  are combined, by the freewheel structure, the chair bottom support member  73  for changing the inclination of the seating bottom portion  15  is separated from the first chair electric drive section  74   a , the second chair electric drive section  74   b , and the third chair electric drive section  74   c , and the inclination of the seating bottom portion  15  can be changed by the bed bottom support member  18 . That is, in a state where the wheelchair  72  and the bed main body portion  10  are combined, the chair bottom support member  73  of the wheelchair  72  performs the posture change following the action of the seating bottom portion  15  of the wheelchair  72 . When the transmission of the force for the posture change of the seating bottom portion  15  of the wheelchair  72  to the chair bottom support member  73  is blocked by the freewheel structure serving as one example of the force transmission switching mechanism, the seating bottom portion  15  of the wheelchair  72  is not supported by the chair bottom support member  73 . The transmission of the force for the posture change of the seating bottom portion  15  indicates transmission of drive forces from the first chair electric drive section  74   a , the second chair electric drive section  74   b , and the third chair electric drive section  74   c.    
     In such a way, by respectively actuating the chair bottom support member  73  by the first chair electric drive section  74   a , the second chair electric drive section  74   b , and the third chair electric drive section  74   c  via the freewheel structure, the support member supporting the seating bottom portion  15  can be switched from the chair bottom support member  73  to the bed bottom support member  18  by the support switching mechanism. 
     It should be noted that in the wheelchair  72 , the postures of the chair knee bottom member  15   c , the chair leg first bottom member  15   d , and the chair leg second bottom member  15   e  relative to leg surface parts may be changed in conjunction with the action of the chair back bottom member  15   a . In this case, the posture change of the wheelchair  72  can be performed by a single chair electric drive section. Thus, the wheelchair  72  can be formed in a simple configuration and the weight thereof can be reduced. In the above description, the chair bottom support member  73  and the chair electric drive sections  74   a  to  74   c  are separated by the freewheel structure. However, the chair electric drive sections  74   a  to  74   c  may be freed by a clutch or the like. 
     It should be noted that in the case where the wheelchair  9 ,  72  has a tilt mechanism which is often adopted in a general wheelchair in the first and the second embodiments, the wheelchair may be combined with or separated from the bed main body portion  10  in an inclined state by utilizing the tilt mechanism. 
     It should be noted that by appropriately combining arbitrary embodiments or modification examples among the above various embodiments or modification examples, effects provided in embodiments and the modification examples can be obtained. 
     INDUSTRIAL APPLICABILITY 
     With the bed of the present invention, there is no need for transferring itself between the bed and the wheelchair which is necessary in a conventional example. The caregiver can transfer the care-receiver from the bed to the wheelchair and from the wheelchair to the bed without taking up the care-receiver. Therefore, the bed is useful in an ordinary house, a hospital facility, and a nursing care facility where a person in need of care resides. 
     Although the present invention has been fully described in connection with the preferred embodiments thereof with reference to the accompanying drawings, it is to be noted that various changes and modifications are apparent to those skilled in the art. Such changes and modifications are to be understood as included within the scope of the present invention as defined by the appended claims unless they depart therefrom.