Horizontal articulated robot

Abstract

A horizontal articulated robot includes a base, a first arm provided rotatably around a first rotation axis on the base, a second arm provided rotatably around a second rotation axis on the first arm, the second rotation axis being parallel to the first rotation axis, and a main shaft provided in the second arm to be extended in a direction parallel to the second rotation axis. A distance between the second rotation axis and the main shaft is shorter than a length of a straight line connecting the first and the second rotation axes. Additionally, the first arm has a recessed portion formed so as to include a position on a rotation path where a rotation radius around the second rotation axis is equivalent to the distance between the second rotation axis and the main shaft.

1 . A horizontal articulated robot, comprising:
 a base;   a first arm provided rotatably around a first rotation axis on the base;   a second arm provided rotatably around a second rotation axis on the first arm, the second rotation axis being parallel to the first rotation axis; and   a main shaft provided in the second arm and extending in a first direction parallel to the second rotation axis,   wherein a distance between the second rotation axis and the main shaft is less than a distance between the first rotation axis and the second rotation axis,   the first arm has a recess selectively accommodating the main shaft therein, and   the first arm is invertibly mountable to the base to dictate a rightward or leftward facing direction of the recess.   
     
     
         2 . The horizontal articulated robot according to  claim 1 , wherein the recess comprises a curved portion of the first arm. 
     
     
         3 . The horizontal articulated robot according to  claim 1 , wherein the recess is located at an intersection of a straight line extending between the first and second rotation axes and a rotation path where a rotation radius around the second rotation axis is equivalent to the distance between the second rotation axis and the main shaft such that at least a part of the main shaft can be located at the intersection. 
     
     
         4 . The horizontal articulated robot according to  claim 1 , further comprising:
 a first connection shaft protruding from the base, the first connection shaft rotating around the first rotation axis, and   a second connection shaft protruding from the second arm, the second connection shaft rotating around the second rotation axis,   the first arm having a base end connection portion connected to the first connection shaft and an extreme end connection portion connected to the second connection shaft, the base end connection portion being connectable to the first connection shaft on both horizontal surfaces of the first arm, and the extreme end connection portion being connectable to the second connection shaft on both horizontal surfaces of the first arm.   
     
     
         5 . The horizontal articulated robot according to  claim 1  further comprising:
 a wiring duct provided on the base to store wiring, the wiring duct being located in a position to be selectively accommodated by the recessed portion of the first arm.