Method for controlling working machine and working machine

A working machine that controls, by a pilot signal generated according to an operation of an operation device, supply of a working fluid to an actuator that drives a driven object, thereby moving the driven object bidirectionally between a first position and a second position, the working machine comprising:

• a backflow prevention circuit that prevents a flow of the working fluid in a direction to move the driven object from the second position to the first position;
• and
• shuttle valve that disables the backflow prevention circuit by the pilot signal generated during a specific operation, thereby allowing the flow of the working fluid in the direction to move the driven object from the second position to the first position,
• wherein the pilot signal is either a first signal generated during a first operation of the operation device for moving the driven object from the second position to the first position or a second signal generated during a second operation of the operation device for moving the driven object from the first position to the second position, and
• wherein either the first signal or the second signal, as the pilot signal, is input to the backflow prevention circuit via the shuttle valve, thereby disabling the backflow prevention circuit.

A method for controlling a working machine that controls, by a pilot signal generated according to an operation of an operation device, supply of a working fluid to an actuator that drives a driven object, thereby moving the driven object bidirectionally between a first position and a second position, the method comprising:

• preventing a flow of the working fluid in a direction to move the driven object from the second position to the first position by a backflow prevention circuit;
• disabling the backflow prevention circuit if a pressure in a branch passage branching from a working fluid passage from the actuator to the backflow prevention circuit exceeds a threshold value, thereby allowing the flow of the working fluid in the direction to move the driven object from the second position to the first position;
• and
• preventing a backflow of the working fluid from the branch passage to an upstream side of the pilot signal by a check valve.