Patent Publication Number: US-11642781-B2

Title: Robot

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     The present application is a continuation application of the U.S. patent application Ser. No. 15/954,544 filed Apr. 16, 2018, which is a continuation application of the U.S. patent application Ser. No. 15/052,884 filed Feb. 25, 2016, which claims priority under 35 U.S.C. § 119 to Japanese Patent Application No. 2015-040613, filed Mar. 2, 2015. The contents of these applications are incorporated herein by reference in their entirety. 
    
    
     BACKGROUND 
     Field of the Invention 
     The embodiments disclosed herein relate to a robot. 
     Discussion of the Background 
     Japanese Patent No. 5145901 discloses a seven-joint robot that includes a turnable portion, a lower arm, an elbow, an upper arm, and a wrist. The turnable portion is supported on a base. The lower arm, the elbow, the upper arm, and the wrist are coupled to the turnable portion. The wrist has a three-axis configuration. 
     SUMMARY 
     According to one aspect of the present disclosure, a robot includes a base plate rotatable around a rotation axis, a first arm connected to the base plate at a first axis which is perpendicular to the rotation axis and around which the first arm is rotatable, a second arm connected to the first arm at a second axis which is parallel to the first axis and around which the second arm is rotatable, a third arm connected to the second arm at a third axis which is parallel to the first axis and around which the third arm is rotatable, a turnable link connected to the third arm at a fourth axis which is perpendicular to the third axis and around which the turnable link is rotatable, a distal-end swingable portion connected to the turnable link at a fifth axis which is perpendicular to the fourth axis and around which the distal-end swingable portion is rotatable, a distal end connected to the distal-end swingable portion at a sixth axis which is perpendicular to the fifth axis and around which the distal end is rotatable, and a welder connected to the distal end. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       A more complete appreciation of the present disclosure and many of the attendant advantages thereof will be readily obtained as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings, wherein: 
         FIG.  1    is a perspective view of a robot system; 
         FIG.  2    is a perspective view of the robot system illustrated in  FIG.  1    with cables omitted; 
         FIG.  3    is another perspective view of the robot system, seen from another direction; 
         FIG.  4    is still another perspective view of the robot system, seen from still another direction; 
         FIG.  5    illustrates a movable range of a robot; and 
         FIG.  6    illustrates a width of the robot. 
     
    
    
     DESCRIPTION OF THE EMBODIMENTS 
     The embodiments will now be described with reference to the accompanying drawings, wherein like reference numerals designate corresponding or identical elements throughout the various drawings. 
     Robot System 
     As illustrated in  FIGS.  1  to  3   , a robot system  1  includes a robot  2 , a robot controller  100 , a welding controller  200 , and cables C 1  and C 2 . The robot  2  is a multi-articular robot and includes a welder  90  at a distal end  80  of the robot  2 . The robot controller  100  controls the robot  2  to place the welder  90  at a to-be-welded portion of a workpiece W. The welding controller  200  controls the welder  90  upon placement of the welder  90  at the to-be-welded portion. The robot controller  100  is coupled to the robot  2  through the cable C 1 , and the welding controller  200  is coupled to the robot  2  through the cable C 2 . 
     Robot 
     As illustrated in  FIGS.  1  to  4   , the robot  2  includes a base  10 , a turnable portion  20 , a first arm  30 , a second arm  40 , a third arm  50 , a distal-end swingable portion  70 , a distal end  80 , the welder  90 , actuators M 1  to M 7 , and cables C 3  to C 5 . 
     The base  10  is disposed in the vicinity of the position where the workpiece W, which is subjected to work, is placed (the position of the workpiece W). The base  10  is fixed to a floor surface. The base  10  includes a terminal  11  to accept the cables C 1  and C 2 . The terminal  11  is disposed on the rear surface of the base  10  (which is opposite to the position of the workpiece W). 
     The turnable portion  20  is disposed on the base  10  and turnable about a vertical axis line Ax 1 . The turnable portion  20  includes a base plate  21  and a connection portion  22 . The base plate  21  is mounted on top of the base  10  and turnable about the axis line Ax 1 . The base plate  21  has a form of a horizontal plate with an opening  21   a  at a center portion for wiring use. The connection portion  22  is disposed at a position displaced from the axis line Ax 1  and protrudes perpendicularly from the upper surface of the base plate  21 . In the following description, the terms “front”, “rear”, “left”, and “right” will refer to directions that are based on the axis line Ax 1  and that are under the assumption that the connection portion  22  is on the front side. 
     The connection portion  22  is coupled to the base end of the first arm  30 . The first arm  30  is swingable about a horizontal axis line Ax 2  (first axis line). The axis line Ax 2  passes through the connection portion  22 . The base end of the first arm  30  is mounted on one side of the connection portion  22  in a direction along the axis line Ax 2 , and is turnable about the axis line Ax 2 . In  FIGS.  1  to  4   , the one side in the direction along the axis line Ax 2  corresponds to the right side of the robot  2 , and the other side in the direction along the axis line Ax 2  corresponds to the left side of the robot  2 . While the arrangement of the connection portion  22  and the first arm  30  will not be limited to the arrangement illustrated in  FIGS.  1  to  4   , the following description will be based on the arrangement illustrated in  FIGS.  1  to  4   , that is, the one side corresponds to the right side of the robot  2  and the other side corresponds to the left side of the robot  2 . 
     The distal end of the first arm  30  is coupled to the base end of the second arm  40 . The second arm  40  is swingable about an axis line Ax 3  (second axis line). The axis line Ax 3  is parallel to the axis line Ax 2 . In a non-limiting embodiment, the base end of the second arm  40  is mounted on the left side of the distal end of the first arm  30 , and is turnable about the axis line Ax 3 . 
     The second arm  40  has a crank shape that is bent at the portion where the first arm  30  and the second arm  40  are coupled to each other so as to circumvent the first arm  30 . Specifically, the second arm  40  is bent at its base end to the left side relative to the distal end of the second arm  40 , with the base end superposed on the left side of the first arm  30 . In other words, the second arm  40  is bent at its distal end to the right side relative to the base end of the second arm  40 . This configuration eliminates or minimizes the difference in level between the right side surface,  30   a , of the first arm  30  and the right side surface,  40   a , of the second arm  40 . In a non-limiting embodiment, the right side surfaces  30   a  and  40   a  are flush with each other. 
     The distal end of the second arm  40  is coupled to the base end of the third arm  50 . The third arm  50  is swingable about an axis line Ax 4  (third axis line). The axis line Ax 4  is parallel to the axis line Ax 3 . In a non-limiting embodiment, the third arm  50  includes a connection portion  51 , a base plate  52 , a turnable link  53 , a cover  54 , and a cable guide  55 . The connection portion  51  serves as the base end of the third arm  50 . The connection portion  51  is mounted on the left side of the distal end of the second arm  40  and turnable about the axis line Ax 4 . 
     The base plate  52  abuts on the connection portion  51  and has a plate shape with a longitudinal length along the axis line Ax 4 . 
     The turnable link  53  is mounted on one surface of the base plate  52  and turnable about an axis line Ax 5 . The axis line Ax 5  is orthogonal to the axis line Ax 4 . The axis line Ax 5  is orthogonal to the base plate  52 , and the turnable link  53  has a longitudinal shape centered around the axis line Ax 5 . At the distal end of the turnable link  53 , a connection portion  62  is disposed along the axis line Ax 5 . 
     At a left side portion of the base plate  52 , a plurality of junction connectors  61  are disposed. The plurality of junction connectors  61  are used for wiring for the welder  90 , described later. 
     The cover  54  includes a surrounding wall  63  and an introduction portion  64  (see  FIG.  4   ). The surrounding wall  63  has a hollow cylindrical shape that surrounds the turnable link  53 . In a non-limiting embodiment, the surrounding wall  63  is mounted on the base plate  52  and accommodates a part of the cable C 5 . The introduction portion  64  is disposed on the outer circumference of the surrounding wall  63  at its base end (the base plate  52  side), and opens to one side (for example, left side) of the turnable link  53 . 
     The cable guide  55  is disposed on one side of outer circumference of the base plate  52  opposite to the side on which the connection portion  51  is disposed. The cable guide  55  is fixed to the base plate  52 . The cable guide  55  has a ring shape surrounding a line that is along the axis line Ax 4  to allow the cables C 3  and C 4 , described later, to pass through the cable guide  55 . 
     The connection portion  62  of the turnable link  53  is coupled to the base end of the distal-end swingable portion  70 . The distal-end swingable portion  70  is swingable about an axis line Ax 6 . The axis line Ax 6  is orthogonal to the axis line Ax 5 . The distal-end swingable portion  70  includes a base plate  71 , connection portions  72 A and  72 B, and a cable guide  73 . 
     The base plate  71  serves as the distal end of the distal-end swingable portion  70 . The connection portions  72 A and  72 B are disposed on edges of the base plate  71  and protrude perpendicularly from one surface of the base plate  71  to serve as the base end of the distal-end swingable portion  70 . The connection portions  72 A and  72 B are opposed to each other across a center portion of the base plate  71 . The connection portions  72 A and  72 B hold the connection portion  62  between the connection portions  72 A and  72 B in a direction along the axis line Ax 6 , are mounted on the connection portion  62 , and are turnable about the axis line Ax 6 . 
     The cable guide  73  is fixed to the outer surface of any of the connection portions  72 A and  72 B (a surface opposite to the side on which the connection portion  62  is disposed). The cable guide  73  has a ring shape surrounding a line perpendicular to the base plate  71 , and allows the cable C 5 , described later, to pass through the cable guide  73 . 
     The base plate  71  is coupled to the distal end  80 . The distal end  80  is mounted on the other surface of the base plate  71  opposite to the surface on which the connection portions  72 A and  72 B are mounted. The distal end  80  is turnable about an axis line Ax 7 . The axis line Ax 7  is orthogonal to the axis line Ax 6 . The axis line Ax 7  is also orthogonal to the base plate  71 , and the distal end  80  has a solid cylindrical shape centered around the axis line Ax 7 . The distal end  80  has a guide hole  80   a . The guide hole  80   a  penetrates through the distal end  80  in a direction orthogonal to the axis line Ax 7 . The guide hole  80   a  allows the cable C 5 , described later, to pass through the guide hole  80   a.    
     A non-limiting example of the welder  90  is a spot welding gun that includes electrodes  91 A and  91 B. The electrodes  91 A and  91 B are opposed to each other. The welder  90  is mounted on the distal end  80 . In a non-limiting embodiment, the welder  90  is detachably mounted on one side of the distal end  80  opposite to the side on which the distal-end swingable portion  70  is disposed. It is noted that the detachability of the welder  90  relative to the distal end  80  is not essential. Another possible embodiment is that the welder  90  is integral to the distal end  80 . 
     In the embodiment described hereinbefore, the first arm  30 , the second arm  40 , the third arm  50 , and the distal end  80  of the robot  2  are coupled in series to each other. As used herein, the term “coupled” encompasses a connection by way of some other member (for example, the distal-end swingable portion  70 ). 
     In this embodiment, the actuators M 1  to M 7  are each made up of a motor, a reducer, and a brake. 
     The actuator M 1  is fixed to the base plate  21  of the turnable portion  20 , and causes the turnable portion  20  to turn about the axis line Ax 1  in response to supply of electric power. The fixation of the actuator means fixation of the body of the actuator (which is the portion to which the energy supply cable is coupled). This applies to the following description. 
     The actuator M 2  (first actuator) causes the first arm  30  to swing about the axis line Ax 2  in response to supply of electric power. The actuator M 3  (second actuator) causes the second arm  40  to swing about the axis line Ax 3  in response to supply of electric power. The actuators M 2  and M 3  are disposed on the same side in the direction along the axis line Ax 2 . In a non-limiting embodiment, the actuator M 2  is disposed on the left side of the connection portion  22  and fixed to the connection portion  22 . The actuator M 3  is disposed on the left side of the base end of the second arm  40  and fixed to the second arm  40 . 
     The actuator M 4  (third actuator) causes the third arm  50  to swing about the axis line Ax 4  in response to supply of electric power. The actuator M 4  is disposed on the side on which the actuators M 2  and M 3  are disposed in the direction along the axis line Ax 2 . In a non-limiting embodiment, the actuator M 4  is disposed on the left side of the connection portion  51  and fixed to the connection portion  51 . 
     The actuators M 5  to M 7  are fixed to the other surface of the base plate  52  opposite to the one surface on which the turnable link  53  is mounted. The actuator M 5  causes the turnable link  53  to turn about the axis line Ax 5  in response to supply of electric power. The actuator M 6  causes the distal-end swingable portion  70  to swing about the axis line Ax 6  in response to supply of electric power. The actuator M 6  transfers motive power to the distal-end swingable portion  70  through a transfer mechanism made up of a drive shaft, gears, and other elements. The transfer mechanism is built in the turnable link  53 . The actuator M 7  causes the distal end  80  to turn about the axis line Ax 1  in response to supply of electric power. The actuator M 7  transfers motive power to the distal end  80  through a transfer mechanism made up of a drive shaft, gears, and other elements. The transfer mechanism is built in the turnable link  53  and the distal-end swingable portion  70 . 
     The actuators M 5  to M 7  cooperate with each other to freely adjust the posture of the distal end  80 . That is, the actuators M 5  to M 7  are examples of the plurality of posture adjustment actuators to adjust the posture of the distal end  80 . 
     The cable C 3  (first cable) is a cable harness made up of a bundle of a plurality of cables C 31  to C 37  covered with a sheath CS 3 . In this embodiment, the plurality of cables C 31  to C 37  are each made up of a plurality of power supply lines and a plurality of signal lines. 
     The cable C 31  transfers energy (for example, drive power and electrical signals) between the robot controller  100  and the actuator M 1 . The cable C 32  transfers energy (for example, drive power and electrical signals) between the robot controller  100  and the actuator M 2 . The cable C 33  transfers energy (for example, drive power and electrical signals) between the robot controller  100  and the actuator M 3 . The cable C 34  transfers energy (for example, drive power and electrical signals) between the robot controller  100  and the actuator M 4 . The cable C 35  transfers energy (for example, drive power and electrical signals) between the robot controller  100  and the actuator M 5 . The cable C 36  transfers energy (for example, drive power and electrical signals) between the robot controller  100  and the actuator M 6 . The cable C 37  transfers energy (for example, drive power and electrical signals) between the robot controller  100  and the actuator M 7 . 
     One end of the cable C 3  is coupled to the cable C 1  through the terminal  11 . The cable C 3  is disposed on the side opposite to the side on which the actuators M 2  and M 3  are disposed in the direction along the axis line Ax 2 . In a non-limiting embodiment, the cable C 3  is extended out through the opening  21   a  onto the base plate  21  and is wired on the rear side of the base plate  21  and then on the right side the first arm  30  and the second arm  40 . Then, the cable C 3  is wired through the cable guide  55  to the left side of the third arm  50 . That is, in the wiring path between the first arm  30  and the second arm  40 , the cable C 3  is wired on the side opposite to the side on which the actuators M 2  and M 3  are disposed. 
     The cable C 3  is fixed to a right side portion of the base plate  21  with a cable clamp CC 1 , is fixed to the right side surface  30   a  of the first arm  30  with a cable clamp CC 2 , is fixed to the right side surface  40   a  of the second arm  40  with cable clamps CC 3  and CC 4 , and is fixed to a right side portion of the base plate  52  with a cable clamp CC 5 . In a non-limiting embodiment, the cable clamps CC 1  to CC 5  are made of metal. With the cable C 3  held in the cable clamps CC 1  to CC 5 , each cable clamp is fixed to a portion of the robot  2  with a bolt or a similar element. The cable clamps CC 3  and CC 4  are aligned in the longitudinal direction of the second arm  40  (that is, in the direction from the base end to the distal end of the second arm  40 ). 
     The cables C 31  and C 32  (which are branch lines) are branched from the other cables C 33 , C 34 , C 35 , C 36 , and C 37  (main line C 30 ) between the opening  21   a  and the cable clamp CC 1 , and are respectively coupled to the actuators M 1  and M 2 . 
     The cable C 33  (branch line) is branched from the other cables C 34 , C 35 , C 36 , and C 37  (main line C 30 ) between cable clamps CC 33  and CC 34 , and is coupled to the actuator M 3 . The cable C 33  branched from the main line C 30  is wired on the rear surface  40   c  of the second arm  40  (which is the side opposite to the position of the workpiece W) to the left side surface  40   b  of the second arm  40 . 
     The cable C 33  branched from the main line C 30  is wired along a guide member CB 1  to the actuator M 3 . A non-limiting example of the guide member CB 1  is a metal bracket. The guide member CB 1  extends to the right and to the left at a position opposed to the rear surface  40   c . The guide member CB 1  is bent forward at its right end and fixed to the right side surface  40   a . The guide member CB 1  is bent forward at its left end and fixed to the left side surface  40   b . The cable C 33  is covered with the sheath CS 33  at least over the portion along the guide member CB 1 . The portion of the cable C 33  along the guide member CB 1  is fixed to the guide member CB 1  with cable clamps CC 6  to CC 8 . A non-limiting example of each of the cable clamps CC 6  to CC 8  is a resin binding band, and each cable clamp is placed over the sheath CS 33  to bind the cable C 33  to the guide member CB 1 . The cable clamps CC 6  to CC 8  are aligned along the guide member CB 1 , and at least one cable clamp among the cable clamps CC 6  to CC 8  (for example, cable clamp CC 8 ) is disposed at the left end of the guide member CB 1 . 
     Since the cable C 33  is guided along the guide member CB 1 , the cable C 33  is prevented from becoming loose toward outside. This stabilizes the wiring path between the main line C 30  and the actuator M 3 . Since at least one cable clamp among the cable clamps CC 6  to CC 8  is disposed at the left end of the guide member CB 1 , the cable C 33  wired to the actuator M 3  is guided along the left side surface  40   b . Thus, the wiring path to the actuator M 3  is kept to the left side surface  40   b . This configuration further prevents outward looseness of the cable  33 . 
     The cable C 3  now wired to the left side of the third arm  50  through the cable guide  55  separates into the cables C 34 , C 35 , C 36 , and C 37 . The cables C 34 , C 35 , C 36 , and C 37  are respectively coupled to the actuators M 4 , M 5 , M 6 , and M 7 . 
     The cable C 4  (second cable) is a cable harness made up of a bundle of a plurality of cables C 41  and C 42  covered with a sheath CS 4 . In this embodiment, the cables C 41  and C 42  are electric wires to transfer energy (for example, welding power) from the welding controller  200 . This, however, should not be construed in a limiting sense. Another possible embodiment is that the cables C 41  and C 42  are hoses to transfer a fluid for cooling purposes. 
     One end of the cable C 4  is coupled to the cable C 2  through the terminal  11 . Similarly to the cable C 3 , the cable C 4  is wired on the side opposite to the side on which the actuators M 2  and M 3  are disposed in the direction along the axis line Ax 2 . In a non-limiting embodiment, together with the cable  3 , the cable C 4  is extended out through the opening  21   a  onto the base plate  21  and is wired on the rear side of the base plate  21  and then on the right side the first arm  30  and the second arm  40 . Then, the cable C 3  is wired through the cable guide  55  to the left side of the third arm  50 . That is, in the wiring path between the first arm  30  and the second arm  40 , the cable C 4  is wired on the side opposite to the side on which the actuators M 2  and M 3  are disposed. 
     Together with the cable C 3 , the cable C 4  is fixed to the right side portion of the base plate  21  with the cable clamp CC 1 , is fixed to the right side surface  30   a  of the first arm  30  with the cable clamp CC 2 , is fixed to the right side surface  40   a  of the second arm  40  with the cable clamps CC 3  and CC 4 , and is fixed to the right side portion of the base plate  52  with the cable clamp CC 5 . 
     The cable C 4  now wired to the left side of the third arm  50  through the cable guide  55  separates into the cables C 41  and C 42 . The cables C 41  and C 42  are respectively coupled to the plurality of junction connectors  61  on the side opposite to the side on which the turnable link  53  is disposed. 
     The cable C 5  (second cable) is a cable harness made up of a bundle of a plurality of cables C 51  and C 52  covered with a sheath CS 5 . In this embodiment, the cables C 51  and C 52  are similar in kind to the cables C 41  and C 42 . The cable C 51  couples one end of the cable C 41 , which is coupled to one junction connector  61 , to the welder  90 . The cable C 52  couples one end of the cable C 42 , which is coupled to the other junction connector  61 , to the welder  90 . 
     At one end of the cable C 5 , the cables C 51  and C 52  are respectively coupled to the junction connectors  61  on the side of the turnable link  53 . Thus, the cables C 51  and C 52  are respectively coupled to the cables C 41  and C 42  through the junction connectors  61 . 
     The cable C 5  is wired through the introduction portion  64 , the surrounding wall  63 , the cable guide  73 , and the guide hole  80   a  to the vicinity of the welder  90 . From the surrounding wall  63  on, the cable C 5  is wired on the outer surface of the turnable link  53  with enough allowance (looseness) to follow the turning of the turnable link  53 . The cable C 5  through the guide hole  80   a  separates into the cables C 51  and C 52 . The cables C 51  and C 52  are coupled to the welder  90 . 
     Advantageous Effects of the Embodiment 
     As has been described hereinbefore, the robot  2  includes the first arm  30 , the second arm  40 , the third arm  50 , the distal end  80 , the actuator M 2 , the actuator M 3 , the actuator M 4 , and the plurality of the actuators M 5  to M 7 . The first arm  30 , the second arm  40 , the third arm  50 , and the distal end  80  are coupled in series to each other. The actuator M 2  swings the first arm  30  about the axis line Ax 2 . The actuator M 3  swings the second arm  40  about the axis line Ax 3 , which is parallel to the axis line Ax 2 . The actuator M 4  swings the third arm  50  about the axis line Ax 4 , which is parallel to the axis line Ax 2 . The plurality of the actuators M 5  to M 7  adjust the posture of the distal end  80 . The actuators M 2  and M 3  are disposed on the same side in the direction along the axis line Ax 2 . 
     Since the robot  2  includes the second arm  40  in addition to the first arm  30  and the third arm  50 , the movable range of the welder  90  increases. The double-dashed lines illustrated in  FIG.  5    indicate a comparative example in which the second arm  40  is integral to the first arm  30  and unable to swing about the axis line Ax 3 . In the comparative example, due to the limit that the third arm  50  has in moving about the axis line Ax 4 , the welder  90  cannot move further downward from where the welder  90  is illustrated by the double-dashed lines. Contrarily, the robot  2  according to the embodiment allows the second arm  40  to turn about the axis line Ax 3  and thus enables the welder  90  to move further downward. 
     Since the axis line Ax 3  is parallel to the axis line Ax 2 , the robot  2  does not tilt to the right or left even though the second arm  40  swings about the axis line Ax 3 . This configuration ensures diminished gaps between the robot  2  and surrounding machines, apparatuses, and/or devices. 
     Since the actuators M 2  and M 3  are disposed on the same side in the direction along the axis line Ax 2 , the width of the robot  2  (width in the direction along the axis line Ax 2 ) is decreased at least over the portion between the first arm  30  and the second arm  40 . The double-dashed line illustrated in  FIG.  6    indicates a comparative example in which the actuator M 3  is disposed on the side opposite to the side on which the actuator M 2  is disposed in the direction along the axis line Ax 2 . In the comparative example, the actuators M 2  and M 3  respectively protrude to the right and the left. This configuration increases the width of the robot  2 . Contrarily, in the robot  2  according to the embodiment, the actuators M 2  and M 3  are disposed on the same side in the direction along the axis line Ax 2 . This configuration decreases the width of the robot  2  as compared with the comparative example in which the actuators M 2  and M 3  are disposed on opposite sides. Thus, the configuration of the embodiment ensures diminished gaps between the robot  2  and surrounding machines, apparatuses, and/or devices. 
     The actuator M 4  is disposed on the side on which the actuators M 2  and M 3  are disposed in the direction along the axis line Ax 2 . This configuration decreases the width of the robot  2  at least over the portion between the first arm  30  and the third arm  50 . This further diminishes gaps between the robot  2  and surrounding machines, apparatuses, and/or devices. 
     The robot  2  further includes the cable C 3 . The cable C 3  is wired on the side opposite to the side on which the actuators M 2  and M 3  are disposed in the direction along the axis line Ax 2  so as to transfer energy to the actuators M 3  to M 7 . This configuration eliminates or minimizes the need for meandering of the cable C 3  in an attempt to circumvent the actuators M 2  and M 3 , and thus facilitates the wiring of the cable C 3 . Eliminating or minimizing the meandering of the cable C 3  also eliminates or minimizes interference between the cable C 3  and surrounding machines, apparatuses, and/or devices. This further diminishes gaps between the robot  2  and the surrounding machines, apparatuses, and/or devices. 
     The cable C 3  includes the main line C 30  and the cable C 33  (branch line). The main line C 30  is wired on the side opposite to the side on which the actuators M 2  and M 3  are disposed in the direction along the axis line Ax 2 . The cable C 33  is branched from the main line C 30  and wired to the actuator M 3 . This configuration ensures that even if the connection terminal of the actuator M 3  is located on the side opposite to the side of the main line C 30 , the cable C 33  is wired to the connection terminal without meandering of the main line C 30 . This further facilitates the wiring of the cable C 3 . 
     The robot  2  further includes two cable clamps CC 3  and CC 4 . The cable clamps CC 3  and CC 4  hold the cable C 3  and are disposed on the first arm  30  or the second arm  40  to which the actuator M 3  is fixed. The cable C 33  is branched from the main line C 30  between the two cable clamps CC 3  and CC 4 . In this configuration, the actuator M 3  and the branching position of the cable C 33  branched from the main line C 30  are fixed to the same arm. This enhances the durability of the branching position of the cable C 33 . 
     In this embodiment, the actuator M 3  and the cable clamps CC 3  and CC 4  are fixed to the second arm  40 . This, however, should not be construed in a limiting sense. Another possible embodiment is that the actuator M 3  and the cable clamps CC 3  and CC 4  are fixed to the first arm  30 . 
     The first arm  30  is coupled to the base  10 , which is disposed in the vicinity of the position of the workpiece W. The cable C 33  is wired on the side opposite to the position of the workpiece W. This configuration eliminates or minimizes interference between the elements of the robot  2  and the cable C 33  at the time when the distal end  80  of the robot  2  is arranged at the workpiece W. This further enhances the durability of the branching position of the cable C 33 . 
     One arm among the first arm  30  and the second arm  40  has a crank shape that is bent at the portion where the first arm  30  and the second arm  40  are coupled to each other so as to circumvent the other arm. The actuator M 3  is fixed to the one arm. The configuration in which one arm is bent in the form of a crank eliminates or minimizes the difference in level between the side surface (right side surface  30   a ) of the first arm  30  and the side surface (right side surface  40   a ) of the second arm  40  on the side opposite to the side on which the actuators M 2  and M 3  are disposed. This makes the cable C 3  more readily arranged along the first arm  30  and the second arm  40 , and thus further facilitates the wiring of the first cable. 
     In this embodiment, the right side surface  30   a  and the right side surface  40   a  are flush with each other. This configuration makes the cable C 3  even more readily arranged along the first arm  30  and the second arm  40 , and further facilitates the wiring of the first cable. 
     In this embodiment, the second arm  40  has a crank shape that is bent at the portion where the first arm  30  and the second arm  40  are coupled to each other so as to circumvent the first arm  30 , and the actuator M 3  is fixed to the second arm  40 . Around the base end of the first arm  30 , cables and wires to the elements of the robot  2  are concentrated. In view of this situation, the second arm  40  has a crank shape, and this leads to a simplified shape of the first arm  30 , resulting in more room around the base end of the first arm  30 . This configuration further facilitates the wiring of the cable C 3 . 
     It is noted that the second arm  40  being bent in a crank shape is not essential. Another possible embodiment is that the first arm  30  has a crank shape that is bent at the portion where the first arm  30  and the second arm  40  are coupled to each other so as to circumvent the second arm  40 , and that the actuator M 3  is fixed to the first arm  30 . 
     The robot  2  further includes the welder  90  and the cables C 4  and C 5 . The welder  90  is disposed on the distal end  80 . The cables C 4  and C 5  are coupled to the welder  90 . The cables C 4  and C 5  are wired on the side opposite to the side on which the actuators M 2  and M 3  are disposed. This configuration facilitates the wiring of the cables C 4  and C 5 , as well as the wiring of the cable C 3 . It is noted that the cables C 4  and C 5 , which are coupled to the welder  90 , may be more difficult to bend than the cable C 3 . In this case, the facilitated wiring of the wires and cables would be found more advantageous. 
     The second cable, which is coupled to the welder  90 , separates into the cables C 4  and C 5  at the junction connectors  61 . This configuration ensures that the wiring work of the cable C 4  from the base  10  to the base plate  52  and the wiring work of the cable C 5  from the base plate  52  to the welder  90  can be performed independently of each other. This further facilitates the wiring of the second cable. 
     The above-described embodiment should not be construed in a limiting sense. Specifically, while in the above-described embodiment the robot  2  includes three actuators M 5  to M 7  to adjust the posture of the distal end  80 , this should not be construed in a limiting sense. It is possible to conveniently change the arrangement and the number of the actuators M 5  to M 7  in accordance with postures required of the distal end  80 . 
     The welder  90  at the distal end  80  will not be limited to a spot welding gun. Another possible example is a welding torch for arc welding. In this case, the cable C 4  may include a cable to advance a welding material. In another possible embodiment, an end effector other than the welder  90  (for example, a robot hand) is mounted on the distal end  80 . In this case, the cable C 4  may include a cable to transfer drive energy to the end effector. 
     Obviously, numerous modifications and variations of the present disclosure are possible in light of the above teachings. It is therefore to be understood that within the scope of the appended claims, the present disclosure may be practiced otherwise than as specifically described herein.