Umbilical member arrangement unit of robot arm section

An arrangement unit for an umbilical member at a robot arm section, the umbilical member extending to an end effector attached to a front end of a wrist section via a forearm of an industrial robot, the umbilical member being constituted by at least one of a cable adapted to supply power or a signal to the end effector and a tube adapted to supply coolant or activation air to the end effector, the arrangement unit comprising:

• a nonrotating part having a longitudinal axis extending along a longitudinal direction of the forearm;
• a rotating part rotatably attached to one end of the nonrotating part about the longitudinal axis;
• a first fixing member attached to the nonrotating part, wherein the umbilical member is nonslidably fixed to the first fixing member;
• and
• a second fixing member attached to the rotating part so that the second fixing member may integrally rotate with the rotating part, wherein the umbilical member is nonslidably fixed to the second fixing member,
• wherein the second fixing member is positioned at a place where is separated from the first fixing member in the direction of the longitudinal axis by a distance larger than a size of the umbilical member in a cross-sectional direction thereof, the cross-sectional direction being perpendicular to a longitudinal direction of the umbilical member, and
• wherein, when the rotating part is positioned at a center position of a rotational motion range thereof about the longitudinal axis and in an axial view seen along the longitudinal axis,
• the first fixing member is arranged so as to direct the umbilical member, viewed in the direction of the longitudinal axis, along a first tangential line of a circle having a center coinciding with the longitudinal axis,
• the second fixing member is arranged so as to direct the umbilical member, viewed in the direction of the longitudinal axis, along a second tangential line of the circle, the second tangential line being generally perpendicular to the first tangential line, and
• the first and second fixing members are positioned on the same side of a boundary plane on which the longitudinal axis lies, the boundary plane being parallel to the second tangential line.