Pivotal movement control device for boom-equipped working machine

A pivotal movement control device for a boom-equipped working machine comprising (1) a control lever which is movable between inclined positions on either side of a neutral region, (2) pivotal movement instructing means for controlling a pivotal movement of a boom in response to an inclined position of said control lever and (3) position detecting means for detecting the pivotal position of the boom in a lateral direction, wherein the improvement comprises:

• switch means for changing between an automatic mode and a manual mode;
• automatic target stop position control means for (a) storing a target stop signal from said position detecting means when said switch means is changed from the manual mode to the automatic mode, said target stop signal being representative of a target stop position of the boom, (b) controlling a pivotal movement of the boom so as to move the boom to the target stop position and stop the boom at the target stop when (b.sub.1) the boom is positioned away from the target stop position and (b.sub.2) said control lever is moved away from the neutral region in a direction opposite to the direction in which the boom is positioned away from the target stop position and (c) reading a positional signal from said position detecting means during movement of the boom to the target stop position;
• manual control means for controlling a pivotal movement of the boom in response to a signal from said pivotal movement instructing means while said switch means is in the manual mode or while said control lever is operated other than as specified in (b.sub.1) and (b.sub.2) above;
• and
• means for changing from the automatic mode to the manual mode when the boom is positioned away from the target stop position and said control lever is moved away from the neutral region in a direction which corresponds to the direction in which the boom is positioned away from the target stop position.