Abstract:
Since both a driving means for lifting a work and a driving means for turning operation must have been arranged in a conventional work transfer apparatus, the apparatus has been large in size and heavy in weight. A work transfer apparatus is provided with a holding tool for holding a window, i.e., the work, and a supporting arm for movably supporting the holding tool. The window held by the holding tool is transferred by a supporting arm to window frames to which the window is to be assembled, and the posture of the window is changed to that corresponds to the window frames. Furthermore, the supporting arm is configured to be a closed loop link mechanism wherein a plurality of links are connected to form a closed loop. The posture of the holding tool against one link of a pair of links connected to the holding tool of the supporting arm can be fixed.

Description:
FIELD OF THE INVENTION 
       [0001]    The present invention relates to a work conveying apparatus, holding a work, conveying the work to a work-assembly position, and changing the posture of the work corresponding to the work-assembly position. 
       BACKGROUND OF THE INVENTION 
       [0002]    Conventionally, in the assembly line of a vehicle, when a work is assembled to the vehicle, which is difficult for an operator to transfer, set, or assemble (called “a large work” involving a front window or a rear window), a work conveying apparatus is used, which assists to support the work, reduces the load to support the work for the operator, and which assists to convey the work, reduces the load to operate the work. Thus, work conveying apparatus is known as a power assist apparatus. 
         [0003]    As the work conveying apparatus, JP-A-11-245124 discloses the work lifting apparatus including a holder and a supporter, the holder holds the work, the supporter moves the holder vertically and supports to the holder with inclination. This work lifting apparatus detects the inclination of the holder operated by the operator and lifts the holder by the supporter on the detected direction and angle about the inclination of the work. 
         [0004]    The lifting of the holder is achieved, for example, by a driver of the supporter, which moves the supporter telescopically, and the supporter lifts the holder. 
         [0005]    Typically, the work conveying apparatus conveys the work to the position where the work is assembled to the body, then the work is assembled to the body. For example, as the holder is inclined to the supporter, the posture of the work can be turned in accordance with the position. 
         [0006]    The work lifting apparatus includes a driver involving a motor, the driver rotates the holder to the supporter, and the work can be inclined in accordance with that of the body. 
         [0007]    Thus, the work lifting apparatus disclosed JP-A-11-245124 includes two independent drivers for lifting and rotating the work. 
         [0008]    In the work lifting apparatus, for example, when the window as the work is assembled to the window frame of the vehicle as the body, the holder holding the work is moved down by the driver for lifting, and rotated by the driver for rotating, and inclined in accordance with the inclination of the window frame. 
         [0009]    In this case, the rotating of the window is needed to finish during the desired time on tact time of the assembly line, when the heavy article such as the front window or the rear window (“the large work”) is rotated by the desired angle during the desired time, the rotaing driver tends to be large and heavy. 
         [0010]    Furthermore, the lifting driver needs to lift rotating driver as well as the holder and the work. Thus, if the rotaing driver is large and heavy, the lifting driver is needed to have the large capacity of lifting, so that the work lifting apparatus should become large and heavy. 
         [0011]    The purpose of the invention is to provide a new work conveying apparatus, which is constructed to be small and light. 
       SUMMARY OF THE INVENTION 
       [0012]    A work conveying apparatus of the first aspect of the present invention, includes a holder holding the work and a support arm supporting and conveying the holder to the work-assembly position, in which the support arm is constructed as a quadrate closed loop link mechanism connected by plural links, in which the holder is connected by a pair of the links in the plural links, and in which the posture of the holder against the one link in the pair of the links is fixed. 
         [0013]    Due to the above structure, the work conveying apparatus may only include the driving means for lifting the work without the driving means for rotating it, the driving means for rotating is dispensed, so that the weight supported by the arm is lightened, the driving means for lifting the work can be downsized and lightened and altogether the work conveying apparatus can be downsized and lightened. 
         [0014]    In the work conveying apparatus of the present invention, the support arm preferably includes a joint member connecting the pair of the links and the holder rotatably; and a connect member connecting selectively the holder to either the link without relative rotation for fixing the posture of the link. 
         [0015]    Due to the above structure, the holder can be easily and surely fixed the posture against the one link in the pair of the links. 
         [0016]    In the work conveying apparatus of the present invention, the holder preferably includes a drive member for fine tuning the posture of the link. 
         [0017]    Due to the above structure, the accuracy for tuning the posture of the work and the quality for assembling the work to the body can be improved. 
         [0018]    As mentioned above, according to the present invention, the work conveying apparatus dispenses the driving means for rotating is dispensed, so that the weight supported by the arm is lightened, the driving means for lifting the work can be downsized and lightened and altogether the work conveying apparatus can be downsized and lightened. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWING 
         [0019]      FIG. 1  is a side view showing a work conveying apparatus with a support arm shortening vertical length. 
           [0020]      FIG. 2  is a side view showing the work conveying apparatus with the support arm extending the vertical length in the state the rotation angle of an offset link and a first lower link is fixed. 
           [0021]      FIG. 3  is a side view showing the work conveying apparatus with the support arm extending the vertical length in the state the rotation angle of the offset link and a second lower link is fixed. 
           [0022]      FIG. 4  is a ground section view showing the part of a lower joint in the support arm in the state that a piston for fixing the rotation angle is inserted in holes for switching the joint position of the first lower link and the offset link. 
           [0023]      FIG. 5  is a side view showing the part of the lower joint in the support arm 
           [0024]      FIG. 6  is a ground section view showing the part of the lower joint in the support arm in the state that the piston is inserted in the holes for switching the joint position of the second lower link and the offset link. 
           [0025]      FIG. 7  is a ground section view showing the part of the lower joint in the support arm with a motor for fine tuning the angle of the offset link to the first upper link and the second lower link. 
           [0026]      FIG. 8  is a side view showing the work conveying apparatus in the state that the vertical force works the holder by a wire of a balancer structure, which supports the gravity of the holder and the window and cancels the gravity working the support arm. 
           [0027]      FIG. 8  is a side view showing the work conveying apparatus in the state that the vertical force does not work the holder by the wire of the balancer structure, which supports the gravity of the holder and the window and cancels the gravity working the support arm. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0028]    A work conveying apparatus  1  conveys, positions and assembles a work to the given position three-dimensionally, with intended by a worker, in concert with the worker or by itself. The work is difficult for the operator to transfer, set, or assemble (called “a large work” involving a front window or a rear window). 
         [0029]    The work conveying apparatus  1  positions and assembles a window  5  as the work to a rear window frame  7   a  or a front window frame  7   b  of a vehicle  7 , which is transferred to the left along an assembly line L shown in  FIG. 1 . The work conveying apparatus  1  includes a holder  20 , a supporting arm  10 , an overhead trolley  40  and a controller  80 . The holder  20  holds the window  5 . The arm  10  three-dimensionally supports the holder  20 . The trolley  40  is disposed above the arm  10 , and supports and transfers the arm  10  along the parallel direction of the assembly line L. The controller  80  controls the arm  10  and so on. 
         [0030]    The work conveying apparatus  1  positions and assembles the window  5  to the rear window frame  7   a  and the front window frame  7   b  of the vehicle  7 , but it may be applied to apparatuses which assembles the other window involving a side window, the other parts involving a bonnet or the like. 
         [0031]    The trolley  40  includes a main body  41 , wheels  42 . The wheels  42  are set to the body  41 , and engaged to a rail  9 , which is laid down in the transfer direction of the assembly line L. The wheels  42  are engaged to the rail  9 , so that the trolley  40  is supported by the rail  9 . 
         [0032]    Thus, the trolley  40  is supported by the rail  9  and travels along the rail  9  (along the transfer direction of the assembly line L). 
         [0033]    The arm  10  is constructed a quadrate closed loop link mechanism, which is connected by a first upper link  11 , a second upper link  12 , a first lower link  13  and a second lower link  14 . The ends of the links  11  and  12  are connected by an upper joint  15 , the joint  15  is supported by the body  41 , the ends of the links  13  and  14  are connected by a lower joint  18 , the ends of the links  11  and  13  are connected by a first middle joint  16 , the ends of the links  12  and  14  are connected by a second middle joint  17 . 
         [0034]    The joint  15  is an active joint rotatably supporting the links  11  and  12  in the direction of the assembly line L, including motors, in which the one rotates the link  11  around the joint  15 , the other rotates the link  12  around the joint  15 . 
         [0035]    An offset link  22  is connected to the joint  18  and is extended from a body  21  of the holder  20 , and can be rotated around the joint  18  in the direction of the assembly line L. 
         [0036]    The link  22  can fix the rotation angle (the position) selectively against the link  13  or  14 , which are connected to the link  22 . 
         [0037]    The joint  16  is a passive joint rotatably supporting the links  11  and  13  in the direction of the assembly line L, and the joint  17  is a passive joint rotatably supporting the link  12  and  14  in the direction of the assembly line L. 
         [0038]    The arm  10  is not especially limited to be configured as the closed quadrate loop mechanism connected by the four links, may be configured as a closed loop mechanism connected by the different numbers of the link. It may include a pair of the links connected to the link  22 , such as the links  13  and  14  connected to the link  22  by the joint  18 . 
         [0039]    The holder  20  includes plural suction pads  30  (four pads) to hold the window  5 , the pad  30  is disposed at the body  21  of the holder  20 . 
         [0040]    The number of the pads  30  is not especially limited to be four, which is the same number of the corners of the window  5 . The holder  20  may includes the three or more than four pads. 
         [0041]    The controller  80  controls the motor disposed in the joint  15  for driving the arm  10 , the switch either holding or releasing the window  5  by the pads  30  of the holder  20  and the like. 
         [0042]    Due to the work conveying apparatus  1  configured as the above structure, the window  5  is assembled to the rear window frame  7   a  as following. 
         [0043]    As shown in  FIG. 1 , keeping the holder  20  upper by the arm  10 , when the holder  20  holds the window  5 , the ends of which is coated with the adhesive, by the pads  30 , the trolley  40  travels along the rail  9  and the window  5  is conveyed near the rear window frame  7   a.    
         [0044]    Actually, when the window  5  is conveyed to the vehicle  7 , the arm  10  is rotated to shorten the vertical length (the links  11 ,  12  are driven to rotate in the direction in which the inner angles of both links become wide inside the closed link loop), so that the window  5  is kept upper. 
         [0045]    The window  5  is held horizontally by the holder  20  in the upper. 
         [0046]    When the window  5  is conveyed along the rail  9 , the following structure for travelling the trolley may be adopted; for example, the trolley  40  travels along the rail  9  cooperated with the operation of the operator with handling the holder  20 , and the trolley  40  travels along the rail  9  itself. 
         [0047]    When the window  5  is conveyed to the rear window frame  7   a  of the vehicle  7 , the arm  10  is rotated to extend the vertical length (the links  11 ,  12  are driven to rotate in the direction in which the inner angles of both 
         [0048]    links become narrow inside the closed link loop), so that the window  5  is moved down. 
         [0049]    If the work conveying apparatus  1  assembles the window  5  to the rear window frame  7   a , the rotation angle θ 1  of the link  22  to the link  13  is fixed. The rotation angle θ 2  of the link  22  to the link  14  is not fixed, so that the link  22  can rotate against the link  14 . 
         [0050]    When the arm  10  is driven to extend the vertical length and the window  5  is moved down, as shown in  FIG. 2 , the posture of the links  11 ,  12 ,  13  and  14  of the arm  10  is turned from the horizontal posture to the vertical posture. The rotation angle θ 1  to the link  13  is fixed, so that the window  5  is rotated rightward around the joint  18 , which is held by the holder  20  connected to the offset link  22 , and the window inclines leftward, in other word, the position of the left end of the window  5  is upper than that of the right end (see  FIG. 2 ). 
         [0051]    In this case, the window  5  is moved down to the height of the position of the rear window frame  7   a , the rotation angle θ 1  and the like are set, where the slope angle of the rear window frame  7   a  is substantially same as that of the window  5 . 
         [0052]    Thus, after the window  5  is moved down to the position of the rear window frame  7   a , the window  5  is fitted to the rear window frame  7   a  by the operator. 
         [0053]    Further, the window  5  is pressed to the rear window frame  7   a  and the adhesive  6 , coated around the window  5 , is pressed by the window  5  and the rear window frame  7   a , the window  5  is assembled to the rear window frame  7   a.    
         [0054]    If the window  5  is assembled to the front window frame  7   b , the arm  10  is driven to extend the vertical length, the window  5  is moved down, in this case, the rotation angle θ 1  of the link  22  to the link  13  is fixed, the rotation angle θ 2  of the link  22  to the  14  is not fixed, so that the link  22  can be rotated around the link  13 . 
         [0055]    Thus, as shown in  FIG. 3 , the window  5  is moved down by the extending motion of the arm  20 , is rotated leftward around the joint  18 , inclines rightward, in other word, the position of the right end of the window  5  is upper than that of the right end. 
         [0056]    In this case, the window  5  is moved down to the height of the position of the front window frame  7   b , the rotation angle θ 2  and the like are set, where the slope angle of the front window frame  7   b  is substantially same as the window  5 . 
         [0057]    Thus, the offset link  22  can be fixed in the rotation angle θ 1  to the link  13  or in the rotation angle θ 2  to the link  14 , which are connected by the joint  18 . 
         [0058]    The structure capable of fixing the rotation angle θ 1 , θ 2  will be described. 
         [0059]    As shown in  FIGS. 4 and 5 , the links  13 ,  14  and  22  are set, in the rotate center of the joint  18 , the link  22  is arranged between the links  13  and  14 . In the part of the links  13 ,  14  and  22  which are connected by the joint  18  (in the lower ends of the links  13 ,  14  and the upper end of the link  22 ), there are sleeves  13   a ,  13   a ,  14   a ,  14   a ,  22   a  and  22   a  formed arc with the desired width. 
         [0060]    The sleeves  13   a ,  14   a  and  22   a  are formed, which go through the links  13 ,  14  and  22 , respectively, in the direction of the rotate center axis of the joint  18 . 
         [0061]    The numbers of the sleeves  13   a ,  14   a  and  22   a  are not limited, in this embodiment, the two sleeves ( 13   a ,  13   a ,  14   a ,  14   a ,  22   a  and  22   a ) are formed. 
         [0062]    Coupling shafts  18   a  are inserted to the sleeve  13   a ,  14   a  and  22   a , the shafts  18   a  connect the links  13 ,  14  and  22  at the joint  18 . 
         [0063]    The shaft  18   a  can slide along the arc form as the sleeves  13   a ,  14   a  and  22   a.    
         [0064]    The links  13 ,  14  and  22  are connected rotatably around the center of the joint  18 . 
         [0065]    Thus, the shafts  18   a  serve as the coupling member connecting the links  13 ,  14  and  22  rotatably. 
         [0066]    The both ends of the shaft  18   a  are fixed to stops  18   b  (at the side of the link  13 ) and  18   c  (at the side of the link  14 ). 
         [0067]    Thus, the ends of the shafts  18   a  are set to the stops  18   b ,  18   c , so that the shafts  18   a  can be prevented from pulling out the sleeves  13   a ,  14   a  and  22   a  and can fix the relative positions. The positions of the shafts  18   a  are fixed such that the each shaft  18   a  slides in the sleeves  13   a ,  14   a  and  22   a  as the same manner. the each position of the shaft  18   a  is set to the same phase in the sleeves  13   a ,  14   a  and  22   a.    
         [0068]    Holes  13   b ,  14   b  and  22   b  are formed to go through the links  13 ,  14  and  22  along the direction of the rotation axis, and formed inner than the shafts  18   a  inserted to the links  13 ,  14  and  22 . 
         [0069]    The holes  13   b ,  14   b  and  22   b  are formed as circles in which a part of the peripheral is cut straightly (hereinafter called “cut-circle”) in section (see  FIG. 5 ). 
         [0070]    The joint  18  includes a fixing plunger  19 . The plunger  19  includes a piston  19   a , a pin  19   b  and a body  19   c , the piston  19   a  is for fixing the rotation angle and is column which has the cut-circle sectional form to fit the holes  13   b ,  14   b  and  22   b , the pin  19   b  extends from the end of the piston  19   a , and the body  19   c  supports the pin  19   b  slidably along the axis direction. 
         [0071]    The body  19   c  is fixed in the axis direction of the links  13 ,  14  and  22 . 
         [0072]    The piston  19   a  is constructed to change the position of the links  13 ,  14  and  22  in the axis direction by means of sliding the pin  19   b  in the body  19   c.    
         [0073]    The length of the piston  19   a  is designed such that the following condition ( 1 ) and (2) is satisfied. (1) The length is longer than the gap between the links  13  and  22 , shorter than the total length of the gap and thickness of the links  13  and  14 . (2) The length is longer than the gap between the links  14  and  22 , shorter than the total length of the gap and thickness of the links  14  and  22 . 
         [0074]    Thus, according to the slide position of the pin  19   b  in the body  19   c , the piston  19   a  can be set selectively, (1) in the position which the piston  19   a  is inserted to the holes  13   b  and  22   b , the each end of the piston  19   a  does not protrude from the hole  13   b ,  22   b  (see  FIG. 4 ), or (2) in the position which the piston  19   a  is inserted to the holes  14   b  and  22   b , the end of the piston  19   a  does not protrude from the hole  14   b ,  22   b  (see  FIG. 6 ). 
         [0075]    In other words, the piston  19   a  can be switched, (1) in the position which the piston  19   a  is inserted in the holes  13   b  and  22   b , and is not inserted in the hole  14   b  (see  FIG. 4 ), or (2) in the position which the piston  19   a  is inserted in the holes  14   b  and  22   b , and is not inserted in the hole  13   b  (see  FIG. 6 ). The piston  19   a  serve as a member connecting selectively the holder  20  to either the link  13  or  14  without relative rotation for fixing the posture of the links. 
         [0076]    The piston  19   a  has the cut-circle sectional form fitting to the holes  13   b ,  14   b  and  22   b , if the piston  19   a  is inserted in the holes  13   b ,  14   b  and  22   b , the piston  19   a  can not rotate around the holes  13   b ,  14   b  and  22   b , so that the phase of the piston  19   a  is fixed to the holes  13   b ,  14   b  and  22   b  in the rotate direction. 
         [0077]    Thus, (1) if the piston  19   a  is inserted in the holes  13   b  and  22   b , the rotation angle θ 1  of the link  22  to the link  13  is fixed, (2) if the piston  19   a  is inserted in the holes  14   b  and  22   b , the rotation angle θ 2  of the link  22  to the link  14  is fixed. 
         [0078]    Furthermore, the controller  80  can control the slide position in the rotation axis direction of the piston  19   a.    
         [0079]    Due to the above construction, the work conveying apparatus  1  can selectively fixes the rotation angle θ 1  of the link  22  to the link  13  or the rotation angle θ 2  of the link  22  to the link  14 , when the arm  20  is driven in the vertical extending direction and the window  5  is moved down, as shown in  FIG. 2 , if the inclining posture of the holder  20  is turned to the posture inclining leftward, the slide position of the piston  19   a  is controlled to fix the rotation angle θ 1 , and when the window  5  is moved down, as shown in  FIG. 3 , if the inclining posture of the holder  20  is turned to the posture inclining rightward, the sleeve position of the piston  19   a  is controlled to fix the rotation angle θ 2 . 
         [0080]    Thus, in the work conveying apparatus  1 , the rotation angle θ 1  of the links  13  and  22 , or the rotation angle θ 2  of links  14 ,  22  can be selectively fixed, the inclining posture of the holder  20  automatically turns in concert with the arm  10 , so that the means of driving may not be added which rotates the holder  20  (the window  5 ) to change the inclining posture. 
         [0081]    Thus, the work conveying apparatus  1  may only include the driving means for lifting the work without the driving means for rotating it. 
         [0082]    The driving means for rotating is dispensed, so that the weight supported by the arm  10  is lightened, the driving means for lifting the work (the motor disposed in the joint  15 ) can be downsized and lightened. 
         [0083]    The mechanism includes the shafts  18   a  and the piston  19   a , which can fix the posture of the holder against the link  13  or the link  14 , the shafts  18   a  connect the links  13 ,  14  and  22  to rotate each other, the piston  19   a  selectively joints the link  13  or  14  to the holder  20  without rotating each other, so that the holder  20  can be easily and surely fixed the posture against the link  13  or  14 . 
         [0084]    In the alternative structure fixing the rotation angle θ 1  and θ 2 , the angle of the link  22  to the link  13  or  14  can be fine tuned as following. 
         [0085]    As shown in  FIG. 7 , the motor  61  is disposed in the lower joint  18 . The rotation angle of the link  22  to the link  13  or  14  can be fine tuned by the motor  61 . 
         [0086]    In detail, the link  22  includes an inner link  22 A and an outer link  22 B, the link  22 B is arranged in the outside of the link  22 A, the link  22 B supports the holder  20 . 
         [0087]    The link  22 A and  22 B can rotate to the rotation axis of the joint relatively. 
         [0088]    The link  22 B has a pulley peripheral, a driving belt  62  is looped over the link  22 B and the driving shaft of the motor  61  rotating the link  22 B. 
         [0089]    The holes  22   a  and  22   b  are formed in the link  22 A connected to the link  13  and  14 . 
         [0090]    The rotation angle θ 1  and θ 2  of the link  22 A to the link  13  and  14  are respectively fixed by the piston  19   a.    
         [0091]    The main body of the motor  61  is fixed in the side of the link  22 A. 
         [0092]    The other members including the links  13 ,  14  and the plunger  19  are the same as the above described structure, so that they are not described again. 
         [0093]    Due to the above structure, for example as shown in  FIG. 2 , when the rotation angle θ 1  of the links  13  and  22  is fixed and the window  5  is assemble to the rear window frame  7   a , the arm  10  is extended by the vertical length and the window  5  is moved down and moved to the height of the rear window frame  7   a . If the inclination of the rear window  7   a  differs a little from that of window  5 , the link  22 B is rotated to the link  22 A by the motor  61 , the inclination of the window  5  is fine tuned and the inclination of the window  5  can be adjusted to that of the rear window frame  7   a.    
         [0094]    The rotation angle θ 1  of the inner link  22 A to the link  13  is fixed, but the link  22 B is rotated to the link  22 A by the motor  61 , the posture of the holder  20  (window  5 ) against the link  13  is fine tuned. 
         [0095]    Thus, the accuracy for tuning the posture of the window  5  and the quality for assembling the window  5  to the rear window frame  7   a  can be improved. 
         [0096]    The work conveying apparatus  1  can be constructed as following. 
         [0097]    As shown in  FIG. 8 , the work conveying apparatus  1  includes a balancer-structure as following. A wire  73  is suspended between the trolley  40  and the holder  20 , supports the weight of the holder  20  and the window  5 , so that the arm  10  is not effected the load involving the weight during moving and that the load for the motor is reduced which is set in the joint  15  of the arm  10 . 
         [0098]    One end of the wire  73  is connected to the body  41  of the trolley  40 , the other end is connected to the holder  20 . 
         [0099]    A balancer cylinder  71  is set to the body  41 . The cylinder  71  includes a cylinder body  71   a , a piston  71   b  and a pulley  71   c ; the piston  71   b  can move against the body  71   a , the pulley  71   c  is set at the end of the piston  71   b . The piston  71   b  can move to the substantially horizontal direction. 
         [0100]    Another pulley  72  is also set to the body  41 , the wire  73  is looped over the pulley  71   c  and  72 . 
         [0101]    The piston  71   b  of the cylinder  71  is moved, then the length of the wire  73  between the pulley  72  and the holder  20  is changed which is looped over the pulley  71   c  and  72 . Thus, the length of the wire  73  is changed in accordance with moving the window  5  by the arm  10 , so that the weight for the arm  10  is effectively reduced (canceled), in spite of the movement of the arm  10  (the window  5  is moved up by the arm  10  shortened by vertical length or the window  5  is moved down by the arm  10  extended by vertical length). 
         [0102]    In the balancer-structure, if the position of the cylinder  71  and the pulley  72  in the direction to the assembly line L is fixed, as shown in  FIG. 8 , depending on the position of the end of arm  10  (or the holder  20 ) in the direction of the assembly line L, the looped part of the wire  73  over the pulley  72  may be out of the connect part of the holder  20  with respect to the position in the direction of the assembly line L. 
         [0103]    In other words, the wire  73  under the pulley  72  supports the holder  20  and the window  5  at an inclined angle θa to the vertical down. 
         [0104]    In this position, the load F works on the wire  73  along the wire  73  which is connected to the holder  20 , the wire  73  inclines at angle θa to the vertical direction, and the horizontal component of the load [Fsinθa] works on the joint which the wire  73  connected to the holder  20 . 
         [0105]    Thus, when the window  5  is set to the front window frame  7   b , if the horizontal component [Fsinθa] works on the holder  20 , the operation force can not be reflected to the device  80  which the operator controls the holder  20 , therefore, the control of the arm  10  and the like can not be stabilized. 
         [0106]    Then, the work conveying apparatus  1  is constructed that the cylinder  71  is set to the body  41  moving along the direction of the assembly line L, and that the horizontal component [Fsinθa] cannot work on the holder  20  in spite of the moving (posture) of the arm  10 . 
         [0107]    The cylinder  71  and the pulley  72  is set to the body  41  through the slide member including a guide rail  74  and the like, when the horizontal force works on the wire  73  under the pulley  72 , the cylinder  71  and the pulley  72  move together to the direction canceling the force. 
         [0108]    Due to the above construction, as shown in  FIG. 8 , if the wire  73  is inclined to the vertical direction and the horizontal component [Fsinθa] works on the holder  20 , as shown  FIG. 9 , the cylinder  71  moves to the direction canceling the horizontal component [Fsinθa], so that the horizontal component [Fsinθa] cannot work on the holder  20 . 
         [0109]    Furthermore, in this case, the cylinder  71  moves to the position where the wire  73  extends from the pulley  72  to the vertical down. 
         [0110]    Thus, in spite of the posture of the arm  10 , the pulley  72  is set over the joint which the wire is connected to the holder  20 , so that the wire  73  can be suspended vertically and the horizontal force is prevented from working on the holder  20 , therefore, the holder  20  can be conveyed and controlled stably. 
       INDUSTRIAL APPLICABILITY 
       [0111]    The present invention is applicable in the industrial instrument as the work conveying apparatus, holding a work, conveying the work to an assembled position, and changing the posture of the work applied to the assembled position.