Patent Document

INCORPORATION BY REFERENCE 
       [0001]    The disclosure of Japanese Patent Application No. 2014-140469 filed on Jul. 8, 2014 including the specification, drawings and abstract, is incorporated herein by reference in its entirety. 
       BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    The invention relates to a care support apparatus that supports a care receiver&#39;s stand-up, transfer, and walking motion. 
         [0004]    2. Description of Related Art 
         [0005]    Japanese Patent Application Publication No. 2001-187089 (JP 2001-187089 A) discloses a care support apparatus that supports a care receiver&#39;s stand-up, transfer, and walking motion, in which a main body includes wheels, a carrier that moves forward and backward and upward and downward, an assistive arm, and a sitting seat and in which the carrier includes a chest support member at a tip of the carrier. The care support apparatus supports the stand-up and transfer motions of the care receiver held by the chest support member by moving the chest support member forward and backward and upward and downward. The care support apparatus supports the walking motion of the care receiver holding the chest support member and assisted and supported at the hip by the assistive arm or supported by a sling installed on the chest support member. Moreover, the care support apparatus can be used as a wheelchair when the care receiver sits in the sitting seat and a caregiver operates the care support apparatus. 
         [0006]    Japanese Patent Application Publication No. 2011-92324 (JP2011-92324 A) discloses a care support apparatus that supports the care receiver&#39;s stand-up motion and that includes holding sections arranged at respective tips of links pivotally coupled together to hold the care receiver and wheels provided at a lower portion of the apparatus. 
         [0007]    When the care receiver makes the stand-up or transfer motion, a strong force acts on the care support apparatus. Consequently, the care support apparatus needs to be stable, and thus, the distance between the wheels is preferably long. When the care receiver makes the walking motion, the distance between the wheels is preferably short in order to facilitate changes in direction of the care support apparatus. In the conventional apparatuses described in JP 2001-187089 A and JP 2011-92324 A, the wheels are fixedly arranged, precluding the optimum distance from being set between the wheels for each motion. 
       SUMMARY OF THE INVENTION 
       [0008]    An object of the present invention is to provide a care support apparatus that extends the distance between wheels for stand-up and transfer motions to improve stability during the stand-up and transfer motions and that shortens the distance between the wheels for walking to facilitate changes in direction. 
         [0009]    A care support apparatus that is an aspect of the present invention has a main body and a lateral pair of leg links held by the main body. In the care support apparatus, when a shape of the leg links is changed, the care support apparatus is changed into a form suitable for a care receiver&#39;s stand-up, transfer, walking, or movement to support the care receiver&#39;s stand-up, transfer, walking, or movement. The leg links include a first link provided with a first wheel at one end of the first link and a second link provided with a second wheel at one end of the second link and coupled to the first link at another end of the second link so as to be rotatable around a first axis. When, with the first wheel and the second wheel in contact with a ground surface, the second link is rotated around the first axis such that the first wheel and the second wheel approach each other, a height of the main body from the ground surface increases. 
         [0010]    In the care support apparatus in the above-described aspect, the distance between the first wheel and the second wheel decreases with an increase in height of the main body. An operation of increasing the height of the main body is used to support the care receiver&#39;s transfer and stand-up motions. Thus, when the care receiver takes a low posture and a strong force acts on the care apparatus, the distance between the wheels is long and the care support apparatus is very stable. When the care receiver assumes a standing position, the distance between the wheels decreases to facilitate changes in direction during walking. A care support apparatus can be implemented which is very stable during transfer and stand-up and which easily changes the direction during walking. 
         [0011]    In the care support apparatus in the above-described aspect, the first link may be held by the main body so as to be rotatable around a second axis parallel to the first axis. 
         [0012]    In the care support apparatus in the above-described aspect, since the first link is rotatable with respect to the main body, the angle of the main body with respect to the ground surface can be set to match an orientation suitable for transfer and stand-up or walking. 
         [0013]    In the care support apparatus in the above-described aspect, one end of a third link may be coupled to another end of the first link so as to be rotatable around a third axis parallel to the first axis, and another end of the third link may be held by the main body so as to be rotatable around a fourth axis parallel to the first axis. 
         [0014]    In the care support apparatus in the above-described aspect, since the one end of the third link is rotatably coupled to the another end of the first link, the degree of freedom of up and down operation of the main body is high. Thus, the optimum position of the main body can be set for transfer and stand-up or walking. 
         [0015]    The care support apparatus in the above-described aspect may further include a pair of seat members that is held by the main body or the leg links and is movable, the seat members forming a seat surface by approaching each other. 
         [0016]    In the care support apparatus in the above-described aspect, since the seat surface is formed by the seat members approaching each other, the seat members are separately stored when the seat surface is not used. This enables a reduction in storage space, preventing the care receiver&#39;s motion from being obstructed. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0017]    The foregoing and further features and advantages of the invention will become apparent from the following description of example embodiments with reference to the accompanying drawings, wherein like numerals are used to represent like elements and wherein: 
           [0018]      FIG. 1  is a schematic diagram depicting an overall configuration of the present embodiment; 
           [0019]      FIG. 2  is a sectional view taken along the direction of arrow A in  FIG. 1 ; 
           [0020]      FIG. 3  is a sectional view taken along line B-B in  FIG. 2 ; 
           [0021]      FIG. 4  is a diagram of a care support apparatus when a care receiver uses the care support apparatus in a sitting position; 
           [0022]      FIG. 5  is a diagram of the care support apparatus when the care receiver uses the care support apparatus in a standing position; 
           [0023]      FIG. 6  is a diagram of the care support apparatus when the care receiver uses the care support apparatus as a wheelchair; 
           [0024]      FIG. 7  is a side view depicting a second embodiment; and 
           [0025]      FIG. 8  is a sectional view taken along line C-C in  FIG. 7 . 
       
    
    
     DETAILED DESCRIPTION OF EMBODIMENTS 
       [0026]    Embodiments of the present invention will be described below with reference to the attached drawings. 
         [0027]    With reference to  FIGS. 1 to 3 , a care support apparatus in a first embodiment of the present invention will be described. 
         [0028]    As depicted in  FIG. 1 , a care support apparatus  1  includes, on a right side surface of a main body  2 , a first link  3 R provided with a first wheel  5 R at a lower end of the first link  3 R and a second link  4 R engaged with an intermediate portion of the first link  3 R and provided with a second wheel  6 R at a lower end of the second link  4 R; the first link  3 R and the second link  4 R serve as right leg links. The care support apparatus  1  includes, on a left side surface of the main body  2 , a first link  3 L provided with a first wheel  51  at a lower end of the first link  3 L and a second link  4 L engaged with an intermediate portion of the first link  3 L and provided with a second wheel  6 L at a lower end of the second link  4 L; the first link  3 L and the second link  4 L serve as left leg links. The second wheels  6 R and  6 L may be configured to function as casters or turning wheels. 
         [0029]    At the front of the care support apparatus  1 , seat members  70 R and  70 L rotatably held by the main body  2  are arranged. The seat members  70 R and  70 L each rotate about a rotation axis so as to reduce the distance between the seat members  70 R and  70 L to approach each other, thus providing a seat surface  7  on which the care receiver can sit. A handle  8  is provided at an upper portion of the main body  2 . 
         [0030]    As seen in a sectional view of the right leg link depicted in  FIG. 3 , the first link  3 R and the main body  2  are rotatably engaged with each other via a second axis P defined by two bearings  9 R. The first link  3 R is driven by a motor  10 R to rotate around the second axis P with respect to the main body  2 . The second link  4 R and the first link  3 R are rotatably engaged with each other via a first axis Q defined by two bearings  11 R. The second link  4 R is driven by a motor  7 R to rotate around the first axis Q with respect to the main body  2 . In the left leg link, each of the first and second links  3 L and  4 L is similarly rotated by a motor. 
         [0031]    In a side view of the right leg link depicted in  FIG. 2 , an angle α 1  is subtended between a line m perpendicular to a ground surface F of the care support apparatus  1  in a low form depicted by a solid line and a straight line connecting the second axis P with the center of rotation of the first wheel  5 R. An angle β 1  is subtended between a straight line connecting the first axis Q with the center of rotation of the first wheel  5 R and a straight line joining the first axis Q with the center of rotation of the second wheel  6 R. In this case, the distance between the center of rotation of the first wheel  5 R and the center of rotation of the second wheel  6 R is denoted by L 1 . 
         [0032]    In this state, the second link  4 R is rotated clockwise by the motor  7 R so as to set an angle β 2  between the straight line joining the first axis Q with the center of rotation of the first wheel  5 R and the straight line joining the first axis Q with the center of rotation of the second wheel  6 R. At the same time, the first link  3 R is rotated counterclockwise by the motor  10 R so as to set an angle α 2  between the line m and the straight line joining the second axis P with the center of rotation of the first wheel  5 R. Then, the form is changed as depicted by a dashed line to change the distance between the center of rotation of the first wheel  5 R and the center of rotation of the second wheel  6 R to L 2 , increasing the distance of the second axis P from the ground surface F. In this case, when the relationship between the rotation angles of the links is expressed by β 1 −β 2 =2×(α 1 −α 2 ), the angle of the main body  2  with respect to the ground surface F is maintained constant. 
         [0033]    When used to support the care receiver&#39;s transfer or stand-up, the care support apparatus  1  is operated as follows. When the main body  2  is low and the seat member  70 R and the seat member  70 L are not close to each other and open in a lateral direction and do not form the seat surface  7 , the care receiver in a sitting position who is sitting in a chair or the like grips the handle  8 , and assumes a position in which the care receiver&#39;s upper body lies over the main body  2 , as needed. 
         [0034]    A care receiver operates an operating member not depicted in the drawings to rotate the first link  3 R and the second link  4 R to raise the main body  2  to a desired height as depicted in  FIG. 5 . When the care receiver assumes a half-crouching or standing position, the care receiver stops the rotation. In an initial stage of this operation, a strong forward pulling force acts on the care support apparatus  1  in order to pull up the care receiver. However, the distance between the first wheel  5 R and the second wheel  6 R is long, and the care support apparatus  1  is thus stable. 
         [0035]    The care receiver moves and turns the care support apparatus  1  to move to a desired position. At this time, the distance between the first wheel  5 R and the second wheel  6 R is shortened to reduce a moment of force acting as resistance at the time of the turning, thus facilitating the turning. Furthermore, when the second wheel  6 R is a turning wheel, the turning radius of the care support apparatus  1  can be reduced. 
         [0036]    The care receiver operates the operating member to rotate the first link  3 R and the second link  4 R to lower the main body  2  to a desired height. When the care receiver assumes the sitting position at a desired position of the apparatus, the care receiver stops the rotation. 
         [0037]    When the care support apparatus  1  is used for gait training for the care receiver, the care receiver in the standing position grips the handle  8  to support the upper body, while pushing the care support apparatus  1  to move in a desired direction as depicted in  FIG. 5 . At this time, the main body  2  is at a high position, and the distance between the first wheel  5 R and the second wheel  6 R is short. This reduces a moment of force acting as resistance when the care support apparatus  1  changes its direction, which allows the care receiver to more easily operate the care support apparatus  1 . 
         [0038]    When the care receiver is tired from the gait training, the seat members  70 R and  70 L are rotated around attachment shafts thereof to reduce the gap between the seat members  70 R and  70 L to move the seat members  70 R and  70 L closer to each other, thus forming the seat surface  7  as depicted in  FIG. 6 . Subsequently, the position of the main body  2  is lowered to allow the care receiver to sit on the seat surface  7  to take a rest. 
         [0039]    Moreover, in the form depicted in  FIG. 6 , the care support apparatus  1  can be used as a self-propelled wheelchair by adding driving means to the first wheels  5 R and  5 L to control the rotation of the first wheels  5 R and  5 L. 
         [0040]    A second embodiment will be described. 
         [0041]    As depicted in  FIG. 7  and  FIG. 8 , a care support apparatus  100  in the second embodiment corresponds to the care support apparatus  1  of the first embodiment in which a third link is added to one end of the first link  3 R. The form of the care support apparatus  100  thus has an increased degree of freedom. 
         [0042]    In a sectional view of a right leg link depicted in  FIG. 8 , a third link  106 R and the main body  2  are rotatably engaged with each other via a fourth axis O defined by the two bearings  9 R. The third link  106 R is rotationally driven by the motor  10 R with respect to the main body  2 . A first link  103 R and the third link  106 R are rotatably engaged with each other via a third axis R defined by two bearings  112 R. The first link  103 R is rotationally driven by a motor  105 R with respect to the third link  106 R. The first link  103 R and a second link  104 R are rotatably engaged with each other via a first axis Q defined by two bearings  113 R. The second link  104 R is rotationally driven by a motor  107 R with respect to the first link  103 R. In a left leg link, a first link, a second link, and a third link are similarly rotationally driven by motors. 
         [0043]    In a side view of the right leg link depicted in  FIG. 7 , an angle α is subtended between the line m perpendicular to the ground surface F of the care support apparatus  100  and a straight line joining the fourth axis O with the third axis R. An angle β is subtended between a straight line connecting the third axis R with the center of rotation of the first wheel  5 R and a straight line joining the first axis Q with the center of rotation of the second wheel  6 R. An angle γ is subtended between the first link  103 R and the third link  106 R. 
         [0044]    The angle α is controlled by the motor  10 R, the angle β is controlled by the motor  107 R, and the angle γ is controlled by the motor  105 R. An appropriate combination of the three angles allows the care support apparatus  100  to assume a form that matches the care receiver&#39;s positions ranging from the sitting position to the standing position. 
         [0045]    In the description of the embodiments, the main body  2  is at the constant angle with respect to the ground surface F. However, the angle may be changed when the form of the care support apparatus is changed. 
         [0046]    When the care support apparatus  1  is not used as a wheelchair, the seat surface  7  may be removed from the structure.

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