Patent Publication Number: US-2015082537-A1

Title: Wheelchair and bed to be combined with the same

Description:
TECHNICAL FIELD 
     The present invention relates to a wheelchair having an armrest capable of being deployed and retreated, and a bed to be combined with the same. 
     BACKGROUND ART 
     In nursing care to a care-receiver such as an aged person or an ailing person (hereinafter, referred to as the care-receiver), a wheelchair is used. As a wheelchair, a manually operated type wheelchair to be manually pushed by a care-giver from a back surface thereof to travel, or an electrically driven type wheelchair to be self-propelled by an operation of the care-receiver himself/herself is used. These wheelchairs include armrests for stably supporting an arm or the like. For the care-receiver to get on and off in the side surface direction of the wheelchair, a wheelchair that has a rotatable armrest is proposed (for example, refer to Patent Literature 1). 
       FIG. 8  is a schematic view showing a conventional wheelchair of Patent Literature 1. 
     In  FIG. 8 , a wheelchair  10  includes a carriage portion  11  that travels with wheels  11   a , a seat portion  12  that changes a seating posture of a passenger (care-receiver)  14  by a posture change, and an armrest  13  rotatably supported by a back bottom support surface  12   a  that supports a back of the passenger  14 . 
     By rotating the armrest  13  about a rotation shaft  15 , the armrest  13  can be retreated on the side of the back bottom support surface  12   a  from a deployed state of the armrest  13  shown in  FIG. 8 . The rotation shaft  15  is a shaft parallel to the back bottom support surface  12   a , the shaft extending in the side surface direction of the wheelchair  10 . 
     CITATION LIST 
     Patent Literature 
     
         
         Patent Literature 1: JP 2004-275486 A 
       
    
     SUMMARY OF INVENTION 
     Technical Problem 
     However, with the configuration of the conventional wheelchair  10 , there is a need for making an elbow and a shoulder of the passenger  14  avoid a rotation action of the armrest  13  in such a manner that the elbow and the shoulder of the passenger  14  are not brought into contact with the armrest  13  at the time of retreating and at the time of deploying the armrest  13 . 
     The present invention is to solve such a problem, and an object thereof is to provide a wheelchair and a bed to be combined with the same, with each of which there is no need for making an elbow and a shoulder of a passenger avoid at the time of retreating and at the time of deploying. 
     Solution to Problem 
     In order to accomplish the object of the present invention, there is provided a wheelchair comprising: 
     a first seat portion that at least has a first support portion having a back bottom support surface on a surface; 
     first and second armrests; and 
     a third drive unit that forward and backward rotates the second armrest about a first rotation axis, to move the second armrest between a deployed position and a retreated position placed behind the first support portion, 
     wherein the first rotation axis is arranged on a plane perpendicular to the back bottom support surface of the first seat portion and parallel to a front and rear direction of the first seat portion. 
     In order to accomplish the object of the present invention, there is provided a bed comprising: 
     the wheelchair according to the above aspect; and 
     a bed base portion to be combined with the wheelchair to form the bed. 
     Advantageous Effects of Invention 
     According to the present invention, the wheelchair and the bed to be combined with the same, with each of which there is no need for making the elbow and the shoulder of the passenger avoid at the time of retreating and at the time of deploying can be provided. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
       These and other objects and features of the present invention will become clear from the following description taken in conjunction with the embodiments thereof with reference to the accompanying drawings, in which: 
         FIG. 1  is a schematic view showing an action of an armrest in a first embodiment of the present invention; 
         FIG. 2  is a plan view showing the action of the armrest in the first embodiment; 
         FIG. 3A  is a perspective view showing a wheelchair in a state where the armrest in the first embodiment is deployed; 
         FIG. 3B  is a perspective view showing the wheelchair in a state where the armrest in the first embodiment is retreated; 
         FIG. 3C  is an illustrative view schematically showing a rotation action of the armrest and an armrest support portion in the first embodiment; 
         FIG. 4A  is a schematic sectional view showing an armrest structure on an imaginary plane of the wheelchair in the first embodiment; 
         FIG. 4B  is an illustrative view for illustrating a length of the armrest support portion of the wheelchair in the first embodiment; 
         FIG. 5  is a flowchart of combination actions of the wheelchair in the first embodiment; 
         FIG. 6A  is a perspective view of the wheelchair and a bed base portion in a state where a posture change step in the first embodiment is completed; 
         FIG. 6B  is a perspective view of the wheelchair and the bed base portion in a state where an adjacent step in the first embodiment is completed; 
         FIG. 6C  is a flowchart of an action procedure for automatically performing an armrest retreating step of the wheelchair in the first embodiment; 
         FIG. 6D  is a block diagram of a control system of the wheelchair in the first embodiment; 
         FIG. 7A  is a perspective view of the wheelchair and the bed base portion in a state where the armrest retreating step in the first embodiment is completed; 
         FIG. 7B  is a perspective view of the wheelchair and the bed base portion in a state where a bed deformation step in the first embodiment is completed; and 
         FIG. 8  is a schematic view showing a 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 same constituent elements will be given the same reference signs, and description thereof will sometimes be omitted. For easy understanding, the drawings are schematic focusing on the constituent elements. 
     First Embodiment 
       FIG. 1  is a schematic view showing an action of an armrest in a first embodiment of the present invention. 
     As shown in  FIG. 1 , a bed  40  of the first embodiment includes a wheelchair  20 , and a bed base portion  30 . The bed  40  of the first embodiment is formed by combining the wheelchair  20  with the bed base portion  30 . 
     The bed base portion  30  includes first seat portions  31 , a first operating unit  44 , a first drive unit  42 , and a first control unit  39 . The first seat portions  31  are one example of a bed seat portion. The first operating unit  44  is one example of a bed operating unit. The first drive unit  42  is one example of a bed drive unit. The first drive unit  42  lifts the first seat portions by an operation of the first operating unit  44 . It should be noted that in a state of the bed  40  where the wheelchair  20  and the bed base portion  30  are combined with each other, by the operation of the first operating unit  44 , the first seat portions  31  and a second seat portion  22  to be described later are integrated with each other and a posture change is performed by the first drive unit  42 . 
     The wheelchair  20  includes a carriage portion  21 , the second seat portion  22 , a first armrest  23 , a second armrest  24 , a second operating unit  41 , a third drive unit  25 , and a second control unit  36 . The second seat portion  22  is one example of a wheelchair seat portion. The second operating unit  41  is one example of a wheelchair operating unit. The third drive unit  25  is one example of an armrest drive unit. 
     The carriage portion  21  travels with wheels (not shown) and supports the second seat portion  22  thereon. In a case where the wheelchair  20  is used as an electrically driven wheelchair, a second drive unit  43  serving as one example of a wheelchair drive unit is provided, and the wheels of the carriage portion  21  are driven by the second drive unit  43  by an operation of the second operating unit  41 . 
     The second seat portion  22  is a part on which a passenger is seated or leans (rests). The second seat portion  22  at least has a first support portion  22   b  having a back bottom support surface  22   a  on a surface, is supported by the carriage portion  21 , and changes a seating posture of the passenger by a posture change. The first support portion  22   b  is one example of a back bottom support portion of the wheelchair  20 . The back bottom support surface  22   a  is a surface capable of supporting a back of the passenger as shown in  FIGS. 1 and 2  and the like. However,  FIG. 3A  and the like show the second seat portion  22  including the first support portion  22   b  or the like as a bottom member from which a cushion member such as a mat or the like attached to the surface side is removed. In these cases, for example, an imaginary plane on the surface side of the first support portion  22   b  serves as the back bottom support surface  22   a . The second seat portion  22  has a second support portion  22   c  on which buttocks of the passenger are mounted, third support portions  22   d  capable of supporting legs of the passenger, and the like, in addition to the first support portion  22   b . The second support portion  22   c  is one example of a seating portion of the wheelchair  20 . The third support portions  22   d  are one example of a leg support portion of the wheelchair  20 . 
     The first armrest  23  is an armrest placed in one side part (right side part in  FIG. 1  and the like) of the first support portion  22   b , and placed in the side part on the opposite side of the bed base portion  30  at the time of combination with the bed base portion  30 . The first armrest  23  is rotatably supported by the first support portion  22   b  on a plane in the up and down direction. 
     The second armrest  24  is an armrest placed in the other side part (left side part in  FIG. 1  or the like) of the first support portion  22   b , and placed in the side part on the side of the bed base portion  30  at the time of combination with the bed base portion  30 . The second armrest  24  is rotatably supported by the first support portion  22   b . It should be noted that the second armrest  24  shown in  FIG. 1  is placed at a deployed position (protruding position)  24   a  at the time of deployment. The second armrest  24  shown by a broken line in  FIG. 2  is placed at a retreated position  24   b  at the time of retreating. The third drive unit  25  connected to a base end of the second armrest  24  is arranged on the back surface side of the first support portion  22   b . The third drive unit  25  is one example of an armrest drive unit. The second armrest  24  is connected to the third drive unit  25  at one end of an L shape member (L shape portion  35 ) serving as a part thereof. Therefore, the second armrest  24  is rotated by about 180° and moved between the deployed position  24   a  in the side part of the first support portion  22   b  and the retreated position  24   b  on the back surface side of the first support portion  22   b , so as to be deployed and retreated by drive of the third drive unit  25 . Forward and backward rotation actions will be described in detail below. 
     The first embodiment is characterized in that at the time of retreating the second armrest  24  to the retreated position  24   b , the second armrest  24  is moved by an arc trajectory curved as shown by an arrow  26  in such a manner that the second armrest  24  is not brought into contact with an elbow and a shoulder of the passenger of the wheelchair  20 . This trajectory is a route in which a leading end of the second armrest  24  is moved rearward while being rotated so as to go away from the other side part of the first support portion  22   b  and go toward the retreated position  24   b  on a back surface of the first support portion  22   b . It should be noted that at the time of deploying the second armrest  24  to the deployed position  24   a , reverse movement to the above description is performed. That is, at the time of deployment and retreating, the second armrest  24  in the first embodiment is moved in the direction of going away from the side part of the first support portion  22   b  and then moved in the direction of coming close to the back surface of the first support portion  22   b , so as to be moved to draw a large arc. Such movement of the second armrest  24  is particularly effective in the wheelchair  20  to be combined with the bed base portion  30  as in the first embodiment. This is because the passenger seated on the second seat portion  22  of the wheelchair  20  as in the first embodiment is highly possibly seated close to the side of the bed base portion  30 , and particularly highly possibly brought into contact with the second armrest  24  on the side of the bed base portion  30 . 
     In the first embodiment, the second armrest  24  is retreated to the opposite side of the bed base portion  30  behind the first support portion  22   b . Thus, a first rotation axis  27  serving as the rotation center of the second armrest  24  is arranged on an imaginary plane  28  serving as a plane perpendicular to the back bottom support surface  22   a  and parallel to the front and rear direction of the second seat portion  22  (front and rear direction of the wheelchair  20 ). Altogether, in the first embodiment, the second armrest  24  is arranged and inclined with respect to the back bottom support surface  22   a  by a predetermined angle (for example, 10° or more and 170° or less in the first embodiment, 45° as one specific example). By arranging the first rotation axis  27  on the imaginary plane  28 , the second armrest  24  of the first embodiment is moved and retreated while a posture of an upper surface of the second armrest  24  (surface on which an arm of the passenger is placed, the arm mount surface  24   a - 1 ) is changed in the vertical direction as a retreating action progresses. By moving the second armrest  24  in such a way, even in a case where the retreating action of the second armrest  24  is performed while the passenger places his/her arm on the arm mount surface  24   a - 1 , the arm of the passenger slips off onto a knee or a thigh from the arm mount surface  24   a - 1 . Therefore, upon the retreating action of the second armrest  24 , the arm of the passenger is less possibly nipped between the second armrest  24  and another member, so that safety is obtained. Further, by the retreating action of the second armrest  24 , the passenger is not required to perform not only an action of making the shoulder avoid but also an action of lowering the arm from the arm mount surface  24   a - 1  of the second armrest  24 . By arranging the first rotation axis  27  on the imaginary plane  28 , the third drive unit  25  can be formed by a single-axis motor. Thus, a configuration that the second armrest  24  is retreated to the back surface of the first support portion  22   b  can be realized as a simple configuration. 
     It should be noted that at the deployed position  24   a  protruding forward, the arm mount surface  24   a - 1  of the second armrest  24  is arranged along the horizontal direction or placed at an inclination angle of about 90° with respect to the back bottom support surface  22   a . Meanwhile, at the retreated position  24   b  moved to the back surface side, the second armrest  24  does not protrude toward the side from the first support portion  22   b  but is placed on a back surface of the back bottom support surface  22   a.    
     The trajectory of the arrow  26  will be described with using  FIGS. 2 and 3A  to  3 C.  FIG. 2  is a plan view of the bed  40  showing an action of the second armrest  24  in the first embodiment. 
       FIG. 3A  is a perspective view showing the wheelchair  20  in a state where the second armrest  24  is placed at the deployed position  24   a .  FIG. 3B  is a perspective view showing the wheelchair  20  in a state where the second armrest  24  is placed at the retreated position  24   b.    
     As shown in  FIG. 3A , the second operating unit  41  configured of a joystick, buttons, or the like is arranged in a leading end of the first armrest  23  placed on the opposite side of the bed base portion  30  at the time of combination. In the wheelchair  20 , by control of the second control unit  36  based on the operation of the second operating unit  41 , a traveling action, a posture change action of changing a posture of the second seat portion  22 , and actions of retreating and deploying the second armrest  24  can be performed. The second control unit  36  is arranged in the carriage portion  21  or the like. In the first embodiment, as shown in  FIG. 3B , the second armrest  24  retreated to the retreated position  24   b  is placed in such a manner that the arm mount surface  24   a - 1  of the second armrest  24  is parallel to the back bottom support surface  22   a  on the back surface of the back bottom support surface  22   a.    
     A rotation action of the second armrest  24  between the deployed position  24   a  and the retreated position  24   b  is set to be performed in a state where the wheelchair  20  is in a tilt posture in the following description. However, as shown in  FIG. 3B , this rotation action can also be performed when the wheelchair  20  is in a chair posture. For example, when the passenger moves to a bathroom or the like by the wheelchair  20  and gets off the wheelchair  20  in the lateral direction, based on the operation of the second operating unit  41 , the rotation action of the second armrest  24  is performed, so that the passenger can easily get on and off. 
     Successively, with using  FIG. 4A , a structure of the third drive unit  25  of the wheelchair  20  of the first embodiment will be described.  FIG. 4A  is a schematic sectional view of a vicinity part of the back bottom support surface  22   a  and the third drive unit  25  on the imaginary plane  28 . 
     As shown in  FIG. 4A , the third drive unit  25  of the first embodiment includes a housing  25   a , a worm gear  25   b , a worm wheel  25   c , and a motor  25   m . The housing  25   a  is fixed to the back surface of the first support portion  22   b . The worm gear  25   b  is rotatably supported by the housing  25   a , and coupled to a rotation shaft of the motor  25   m  fixed to the housing  25   a . The worm wheel  25   c  is rotatably supported by the housing  25   a  and coupled to the worm gear  25   b , and converts forward and backward rotation of the motor  25   m  into forward and backward rotation about the first rotation axis  27  via the worm gear  25   b  and the worm wheel  25   c . By fixing the worm wheel  25   c  to the L shape portion  35  of the second armrest  24 , the second armrest  24  performs the rotation action about the first rotation axis  27 . 
     An angle between the second armrest  24  at the deployed position  24   a  and the back bottom support surface  22   a  is θa, an angle between the first rotation axis  27  and the back bottom support surface  22   a  is θb, and an angle made by the back bottom support surface  22   a  with the horizontal direction  38  is θc. The larger the angle θb is, the more outward (going away from the wheelchair  20 ) a trajectory of the second armrest  24  is expanded. Thus, the shoulder of the passenger can be more reliably avoided. However, since the trajectory of the second armrest  24  is expanded outward, the arm of the passenger slips off to a position away from a body. Therefore, in order to reduce a burden of the passenger, there is a need for setting a proper value as a value of the angle θb. In the first embodiment, θb=θa/2 is set so that the trajectory of the second armrest  24  reliably avoids the shoulder of the passenger, and in a case where the arm of the passenger slips off, the arm slips off near the body of the passenger. 
     It should be noted that in the first embodiment, θa+θc=180° is set so that the arm mount surface  24   a - 1  is horizontal at the deployed position  24   a . However, the angle of θa is desirably changed in accordance with the passenger, for example θa=90° is set or the like in a case where a passenger having a narrow elbow movable range due to muscle contracture or the like is seated. 
     Successively, with using  FIG. 4B , a length of the L shape portion  35  will be described. The first armrest  23  is fixed to the first support portion  22   b  at a fixing portion  23   a  slidable in the lateral direction in the figure.  FIG. 4B  shows a state where the fixing portion  23   a  and the first armrest  23  accommodated on the back side of the first support portion  22   b  are pulled out. In a case where a width of this first armrest  23  is d1, a width of the second armrest  24  is d2, and a width of the first support portion  22   b  is D, a length L of the L shape portion  35  from a L shape bending portion of the second armrest  24  (inner end of the arm mount surface  24   a - 1 ) to the first rotation axis  27  (rotation center of the worm wheel  25   c ) is required to be L={D+(d1−d2)}/2 or less in the first embodiment. That is, in the first embodiment, the first rotation axis  27  is placed offset from the center in the width direction of the second seat portion  22 . This is a configuration that the second armrest  24  can be reliably rotated via the L shape portion  35  without contact with the first armrest  23 , and the second armrest  24  does not protrude from the first support portion  22   b  in the lateral direction at the retreated position  24   b.    
     It should be noted that in a case where there is no need for accommodating the fixing portion  23   a  of the first armrest  23  on the back of the first support portion  22   b , the length L may be L=(D+d1)/2 or less. 
     By combining the wheelchair  20  described above with the bed base portion  30 , the second seat portion  22  and the first seat portions  31  are arranged on the same plane, so as to be utilized as the bed  40 . In the bed  40  of the first embodiment, by separating a part thereof and utilizing the part as the wheelchair  20 , an action (transferring action) of moving a care-receiver (passenger) from the bed  40  to the wheelchair  20  can be simply performed. 
     With using  FIGS. 5 to 7B , combination actions of combining the wheelchair  20  of the first embodiment with the bed base portion  30  to form the bed  40  will be described. The series of actions are performed by the control of the second control unit  36  based on the operation of the second operating unit  41 . 
       FIG. 5  is a flowchart showing the combination actions of combining the wheelchair  20  with the bed base portion  30 .  FIG. 6A  is a perspective view of the wheelchair  20  and the bed base portion  30  in a state where a posture change step is completed.  FIG. 6B  is a perspective view of the wheelchair  20  and the bed base portion  30  in a state where an adjacent step is completed.  FIG. 7A  is a perspective view of the wheelchair  20  and the bed base portion  30  in a state where an armrest retreating step is completed.  FIG. 7B  is a perspective view of the wheelchair  20  and the bed base portion  30  in a state where a bed deformation step is completed. It should be noted that in the figures, cushion members such as a mat originally provided in the bed and the wheelchair are omitted for clarifying the structure. 
     At the time of combining the wheelchair  20  with the bed base portion  30 , the passenger operates the second operating unit  41  to provide a combination instruction to the bed base portion  30 . When the combination instruction is provided from the passenger, the combination actions of the wheelchair  20  and the bed base portion  30  are performed by the control of the second control unit  36  based on the flowchart shown in  FIG. 5 . 
     Firstly, in a posture change step S 1 , the second control unit  36  of the wheelchair  20  changes the posture of the second seat portion  22  into the tilt posture as shown in  FIG. 6A . The tilt posture is a posture in which the second seat portion is inclined rearward by about 30° to 45° while being in the chair posture. 
     Successively, in an adjacent step S 2 , by moving the wheelchair  20  in the tilt posture into a recess  32  of the bed base portion  30  by the control of the second control unit  36 , the wheelchair  20  is placed to be adjacent to the bed base portion  30  as shown in  FIG. 6B . Completion of the adjacent step S 2  is detected by a contact sensor  37  (refer to  FIG. 6A ) serving as one example of a combination detecting unit. By bringing the contact sensor  37  provided in the wheelchair  20  on the side of the bed base portion  30  into contact with the bed base portion  30  and turning the contact sensor  37  on, the completion of the adjacent step S 2  is detected, and the second control unit  36  outputs a detection signal (Step S 11  of  FIG. 6C ). In a case where the detection signal is outputted (Yes in Step S 11 ), the motor  25   m  is driven by the second control unit  36 , and the second armrest  24  is rotated from the deployed position  24   a  to the retreated position  24   b  (Step S 12 ). On the contrary, when the wheelchair  20  is brought away from the bed base portion  30 , by bringing the contact sensor  37  away from the bed base portion  30  and turning the contact sensor  37  off, a signal indicating detection cancellation is outputted to the second control unit  36  or the detection signal is not outputted to the second control unit  36  (No in Step S 11 ). In this case, the motor  25   m  is reversely driven by the second control unit  36 , and the second armrest  24  is rotated from the retreated position  24   b  to the deployed position  24   a  (refer to Step S 13 ). An encoder  25   e  is provided in the motor  25   m . By detecting a rotation angle of the rotation shaft of the motor  25   m  by the encoder  25   e , the second armrest  24  is respectively positioned at the retreated position  24   b  and the deployed position  24   a . With such a configuration, in conjunction with an approaching action and a separation action of the wheelchair  20  with respect to the bed base portion  30 , the rotation action of the second armrest  24  (for example, an armrest retreating step S 3 ) can be automatically performed. 
     Successively, in the armrest retreating step S 3 , a retreating action of the second armrest  24  is performed. Specifically, in the armrest retreating step S 3 , as described with using  FIGS. 2 to 3C , the motor  25   m  is driven and rotated by the control of the second control unit  36  based on the operation of the second operating unit  41 , and the second armrest  24  placed at the deployed position  24   a  is rotated by about 180° and retreated to the retreated position  24   b  on the back surface of the back bottom support surface  22   a  and brought into a state shown in  FIG. 7A . In such a way, when the second armrest  24  is moved from the deployed position  24   a  to the retreated position  24   b , by performing the rotation action of the second armrest  24  as in the first embodiment by the wheelchair  20  in the tilt posture, the second armrest  24  can be smoothly moved without contact with other members such as the bed base portion  30 . Further, the configuration of the present embodiment is a configuration that the second armrest  24  can be reliably retreated with a simple structure having only one drive unit. Therefore, by using only one drive unit, the structure for retreating the second armrest  24  can be simplified as a whole. 
     Finally, in a bed deformation step S 4 , by changing the posture of the second seat portion  22  into a flat posture and then raising the first seat portions  31  of the bed base portion  30 , the second seat portion  22  and the first seat portions  31  are brought into the same plane state as shown in  FIG. 7B . As a result, the state is transitioned into a bed state in which the portions can be used as the bed  40 . The flat posture is a posture in which all the surfaces forming the second seat portion  22  are in the substantially one plane state. The first armrest  23  is arranged at a position shown in  FIG. 7B  in such a manner that the second operating unit  41  can be operated in a state of the bed  40 . 
     It should be noted that a lifting mechanism (not shown) of the bed base portion  30  can lift the second seat portion  22  and the first seat portions  31  at the same time in the bed  40  formed by combining the wheelchair  20  and the bed base portion  30 , by control of the first control unit  39  based on the operation of the first operating unit  44 . Similarly, the first drive unit  42  of the bed base portion  30  can integrally change postures of the second seat portion  22  and the first seat portions  31  in the bed  40  formed by combining the wheelchair  20  and the bed base portion  30 , by the control of the first control unit  39  based on the operation of the first operating unit  44 . 
     It should be noted that in the first embodiment, the second armrest  24  is an electrically driven type tube deployed and retreated by the motor  25   m . With such a configuration, in the bed  40 , the combination and separation actions of the wheelchair  20  and the bed base portion  30  can be realized only by the operation of the second operating unit  41 . 
     According to the first embodiment, the wheelchair and the bed to be combined with the wheelchair, with each of which there is no need for making the elbow and the shoulder of the passenger avoid at the time of retreating and the time of deploying can be provided. 
     As described above, in the wheelchair  20  of the first embodiment, when the second armrest  24  is rotated from the deployed position  24   a  to the retreated position  24   b , a base end of the arm mount surface  24   a - 1  of the second armrest  24  starts movement toward the left upper side which is the obliquely rear side of the passenger, and the arm mount surface  24   a - 1  is rotated so as to turn around the outer side of the shoulder of the passenger. Therefore, the arm mounted on the arm mount surface  24   a - 1  naturally drops off to the front side. After that, by continuously rotating the second armrest  24 , the arm mount surface  24   a - 1  is rotated to the retreated position  24   b  which is a position parallel to the back bottom support surface  22   a  and the stopped on the back surface side of the first support portion  22   b . Therefore, the second armrest  24  does not protrude outward from the first support portion  22   b  and not collide with the first armrest  23  on the other side. 
     The second armrest  24  is rotated to come around to the back surface side of the first support portion  22   b  on the rear side of the passenger. Thus, the passenger can smoothly perform the actions without feeling danger. 
     In the first embodiment, the second armrest  24  is placed at the deployed position  24   a  until the wheelchair  20  is brought into the tilt posture. Thus, the passenger of the wheelchair  20  can be prevented from dropping off to the bed base portion  30  or the like from the wheelchair  20  in the middle of combination. 
     It should be noted that the present invention is not limited to the above embodiment but can be implemented in various other modes. For example, although the second armrest  24  is an electrically driven type to be deployed and retreated by the motor  25   m  in the first embodiment, the second armrest may be a manually operated type to be deployed and retreated by human hands. 
     By properly combining the arbitrary embodiment (s) or modification(s) of the aforementioned various embodiments and modifications, the effects possessed by the embodiment(s) or modification(s) can be produced. 
     Although the present invention has been fully described in connection with the 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. 
     INDUSTRIAL APPLICABILITY 
     In the wheelchair of the present invention and the bed to be combined with the same, an action of the passenger to make the shoulder avoid is not required at the time of retreating the armrest so as to reduce the burden of the passenger. Thus, the wheelchair and the bed are useful particularly in the nursing care or medical field.