Robot arm capable of three-dimensionally moving a robot arm member

摘要

In a robot arm for use in converting rotary motion of a rotatable axle located within a main post into linear motion of a chuck arm, a first arm unit is fixed to the rotatable axle while a first gear is fixed to the main post so that the first gear is rotated relative to the first arm unit with rotation of the rotatable axle. Rotation of the first arm unit is transmitted through a first power transmission element to a second gear which is rotatably supported on a first fixed axle. A second arm unit is fixed to the second gear while a third gear is fixed to the first fixed axle so that the third gear is rotated relative to the second arm unit. Relative rotation of the third gear is transmitted via a second power transmission element to a fourth gear fixed to the chuck arm. A first gear ratio of the first to the second gears and a second gear ratio of the third to the fourth gears are equal to 2:1 and 1:2, respectively, so that the rotary motion of the rotatable axle is converted into the linear motion of the chuck arm. In addition, a distance between the rotatable axis and the first fixed axle is equal to a distance between the firts and the second fixed axles. The main post is accommodated within a housing so that the main post is selectively moved downwards and upwards or is rotated.