Abstract:
The present invention provides a cable processor capable of supplying cables to a plurality of hands attached to a forward end portion of an arm without increasing the size of a joint portion of a robot and further without causing a problem of the breaking of wire at the time of operating the robot.  
     There is provided a cable processor of a robot for accommodating a cable such as an air pipe or electric wire inside an arm of the robot, and the cable processor comprises: a casing portion ( 20 ) for accommodating the cable ( 21 ), arranged in a joint drive portion of the robot, wherein the casing portion ( 21 ) is provided with rollers ( 23 ), which are arranged on an inner wall of the casing portion ( 21 ), rotating round a drive shaft of the joint portion.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     The present invention relates to a cable processor for accommodating an air pipe and electrical wire, which will be referred to as “a cable” hereinafter in this specification, inside an arm of a robot.  
         [0002]     Concerning the conventional processing method of processing a cable in the case of accommodating the cable inside an arm of a robot, there is provided a method in which the cable is elastically wound and accommodated in the arm. Concerning this method, for example, refer to Patent Document 1. Further, there is provided a support device in which a cable is extended in a flexible conduit while extended half round in the forward direction and then folded back upward in the U-shaped direction and extended in the flexible conduit half round in the backward direction so that the cable can be accommodated inside the arm. Concerning this support device, refer to Patent Document 2.  
         [0000]     [Patent Document 1] 
         [0003]     JP-A-8-57792  
         [0000]     [Patent Document 2] 
         [0004]     Japanese Patent No. 3452811  
         [0005]     However, according to the method disclosed in Patent Document 1, the following problems may be encountered. In the case where cables are supplied to a plurality of hands attached to a forward end of an arm, it is necessary to provide one or more cables which are elastically wound round a circle, the diameter of which is larger. Therefore, the diameter of the joint portion of a robot is increased. Further, since the cable is elastically wound round the circle, it becomes necessary to provide a space in the direction of the winding shaft. Accordingly, the robot arm is extended in the rotary shaft direction of the joint portion.  
         [0006]     In the support device disclosed in Patent Document 2, since the cable is folded back by a U-shape, the size of the robot joint portion is increased in the direction of the rotary shaft.  
       SUMMARY OF THE INVENTION  
       [0007]     The present invention has been accomplished to solve the above problems of the prior art. It is an object of the present invention to provide a cable processor capable of supplying cables to a plurality of hands attached to a forward end of an arm without increasing the size of a joint portion of a robot and further without causing a problem of the breaking of wire at the time of operating the robot.  
         [0008]     In order to solve the above problems, the present invention has the following constitution.  
         [0009]     The invention described in aspect 1 provides a cable processor of a robot for accommodating a cable such as an air pipe or electric wire inside an arm of the robot, the cable processor comprising: a casing portion for accommodating the cable, arranged in a joint drive portion of the robot, and rollers arranged on an inner wall of the casing, rotating round a drive shaft of the joint portion.  
         [0010]     The invention described in aspect 2 provides a cable processor of a robot, wherein an upper face and a lower face inside the casing are subjected to the treatment of fluorine contained resin.  
         [0011]     The invention described in aspect 3 provides a cable processor of a robot, wherein the contour of the casing is the same as that of the robot arm. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0012]      FIG. 1  is a sectional side view of the arm of the embodiment of the present invention.  
         [0013]      FIG. 2  is an upper view of the arm of the embodiment of the present invention.  
         [0014]      FIG. 3  is a perspective view of the arm of the embodiment of the present invention.  
         [0015]      FIG. 4  is a perspective view of the casing of the embodiment of the present invention.  
         [0016]      FIG. 5  is an upper view of the peripheral portion of rollers provided in the casing.  
         [0017]      FIGS. 6A and 6B  are upper views showing a motion of the cable accommodated in the casing when the hand is rotated.  
         [0018]      FIGS. 7A and 7B  are upper views showing a motion of the cable accommodated in the casing when the hand is rotated. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0019]     Referring to the drawings, a specific embodiment of the method of the present invention will be explained below.  
       Embodiment 1  
       [0020]      FIG. 1  is a view showing an example of the arm of the horizontal multiple joint robot in which the mechanism of the present invention is used.  
         [0021]      FIG. 1  is a sectional central view showing a side the arm, and  FIG. 2  is an upper view showing the arm. In this connection, in order to simplify the explanations, the cover and the other members are removed from  FIG. 2 .  
         [0022]     As shown in  FIG. 1 , the robot includes a first arm  1  and a second arm  2 . The first arm  1  on the base portion side is fixed to the shaft  3  which is moved upward and downward and rotated in a predetermined range. The second arm is attached to the first arm  1  via the bearing.  4  so that the second arm can be rotated in a predetermined range.  
         [0023]     Two hands for seizing and conveying a workpiece are attached to the forward end of the second arm in such a manner that the two hands are vertically put on each other. In this case, the forward end portions of the two hands are omitted in the drawing. Mechanisms for driving the hands  5 ,  6  are built in the first  1  and the second arm  2 .  
         [0024]     When the motor  7  is rotated, the torque generated by the motor  7  is intensified by the speed reducer  9 , and the thus intensified torque is transmitted to the pulley  16  by the motor side pulley  11  and the belt  13 , and the pulley  16  rotates the hand  6  via the bearing  18 .  
         [0025]     In the same manner as that described above, when the motor  8  is rotated, the torque generated by the motor  8  is intensified by the speed reducer  10 , and the thus intensified torque is transmitted to the pulley  15  by the motor side pulley  12  and the belt  14 , and the pulley  15  rotates the hand  5  via the bearing  17 .  
         [0026]     As shown in  FIG. 3 , by the mechanism described above, the hands  5 ,  6 , which are arranged on the same rotating shaft, are operated independently from each other. In this connection, the motor  8  and the speed reducer  10  are located below the motor side pulley  12  in  FIGS. 2 and 3 . However, since the motor  8  and the speed reducer  10  are located on the viewer&#39;s side of the sectional central view of  FIG. 1 , they are not drawn in  FIG. 1 .  
         [0027]     An air pipe and electrical wire, which will be referred to as a cable hereinafter, are supplied to the hand  5  via a hollow portion of the pulley  15 . On the other hand, the cable  21  is supplied to the hand  6  via the casing  20 . The cable  21  is fixed to the support  22  in the second arm  2 . Then, the cable  21  passes through in the casing  20  and fixed to the fixing part  25  which is subordinately operated together with the hand  6 .  
         [0028]     The cables  19 ,  21  are used as electric power source wires or signal wires connected to the sensors mounted on the hands  5 ,  6 . Further, the cables  19 ,  21  are also used as pipes for supplying air to drive the cylinders, which are mounted on the hands  5 ,  6 , or supplying vacuum air used for sucking a workpiece.  
         [0029]      FIG. 4  is a perspective view taken in the direction of arrow A in  FIG. 1 .  FIG. 4  is a view drawn when the casing  20  is taken out from the second arm  2 . As shown in  FIG. 4 , a plurality of roller shafts  24  are arranged in the casing  20  along the inner wall of the casing  20 . The pipe-shaped rollers  23  are arranged in such a manner that each roller shaft  24  is inserted into the hollow portion of each pipe-shaped roller  23 .  
         [0030]      FIG. 5  is an upper view of each roller  23  and roller shaft  24  arranged in the casing  20 . The inner diameter of the hollow portion of the roller  23  is larger than the outer diameter of the roller shaft  24 , and the outer diameter of the roller  23  is smaller than the distance (d in the drawing) from the center of the roller shaft  24  to the inner wall of the casing  20 . Therefore, the roller  23  can be freely rotated in the direction of an arrow shown in  FIG. 5 .  
         [0031]      FIGS. 6 and 7  are upper views showing a state in which the cable  21  accommodated in the casing  20  is acted when the hand  6  is rotated.  
         [0032]     For example, when the hand  6  is rotated in the direction of the reference sign + shown in  FIG. 3 , the fixing part  25  is rotated in the direction of an arrow shown in  FIG. 6A  and the cable  21  in the casing  20  is pulled to the hand  6  side, and the cable  21  is wound round the fixing part  25 , to which the hand  6  is attached, as shown in  FIG. 6B .  
         [0033]     On the contrary, when the hand  6  is rotated in the direction of the reference sign − shown in  FIG. 3  and the fixing part  25  is rotated in the direction of an arrow shown in  FIG. 7A  and the cable  21  in the casing  20  is pushed from the hand  6  side, as shown in  FIG. 7B , the cable  21 , which is wound round the fixing part  25 , spreads in the casing  20  and comes close to the inner wall of the casing  20 . However, since the rollers  23  are arranged on the inner wall, the inner wall of the casing  20  and the cable  21  are not directly contacted with each other. Due to the foregoing, the contact area can be reduced and the frictional resistance can be decreased.  
         [0034]     Further, as described before, since the rollers  23  can be freely rotated round the rotary shaft of the hand  6 , the frictional resistance caused when the cable  21  moves on the wall face of the casing  20  can be reduced. That is, even when the hand  6  is rotated, the cable  21  can be smoothly moved inside the casing  20 . Therefore, no stress and tension are given to the cable  21 , and the breaking of wire, which is caused by the repeated motions, can be prevented.  
         [0035]     Although not shown in the drawing, the upper and lower faces inside the casing are subjected to the treatment of fluorine contained resin. Since the coefficient of friction of fluorine contained resin is low, the cable  21  inside the casing  20  can be more smoothly slid, which can contribute to a reduction of the sliding resistance of the joint portion and a prevention of the breaking of wire of the cable  21 . In this connection, the upper and lower faces inside the casing are not necessarily subjected to the treatment of fluorine contained resin. Alternatively, a tape, which is subjected to the treatment of fluorine contained resin, may be stuck on the inner surface of the casing  20 .  
         [0036]     As can be understood from  FIGS. 2 and 3 , the contour of the casing  20  is the same as that of the second arm  2 . Concerning the volume of the casing  20 , it is sufficient to prepare an area for accommodating the cable  21  which is wound round and separated from the fixing part  25  according to the rotary motion of the hand  6  and also to prepare an area for accommodating the rollers  23 . Concerning the direction of height, it is sufficient to prepare a size of the diameter of the cable  21 . Further, concerning the inside of the forward end portion of the second arm  2 , it is sufficient to provide a space in which the cable  21  can pass through. Therefore, an increase in the size of the robot joint portion of the cable processor of the present invention can be prevented.  
         [0037]     In this embodiment, explanations are made into a case of the robot having two hands attached to the forward end portion of the arm and the rotary shafts of the two hands are arranged in the same axis. However, even when the number of hands is not less than 3, as long as the casing  20  is put in the direction of the rotary shaft of the hand, the present invention can be also applied. In this case, since the contour of the casing  20  is the same as that of the arm as described above, an area of the arm is not increased when a view is taken in the direction of the rotary shaft of the hand. Therefore, it is possible to reduce the space.  
         [0038]     In this connection, explanations are made into a case of the horizontal multiple joint robot. However, the embodiment of the present invention is not limited to the above specific case. The present invention can be applied to a robot having a rotary shaft such as a vertical multiple joint robot.  
         [0039]     The present invention can be applied to joint portions of various type robots and mechanisms in which cables extended to a forward end portion of the drive portion are accommodated.  
         [0040]     According to the invention described in aspect  1 , it is possible to downsize the joint portion of a robot. Further, when the joint is rotated, the cable can be smoothly moved. Therefore, the sliding resistance of the joint portion of the robot can be decreased. Furthermore, since no stress is given to the cable itself, the breaking of wire and the leakage of air can be prevented.  
         [0041]     According to the invention described in aspect  2 , the friction of the cable can be further decreased at the time of rotating the joint.  
         [0042]     According to the invention described in aspect  3 , even in the case of a robot having a plurality of hands at the forward end of the arm, cables can be supplied to the respective hands without increasing the size of the joint portion.