Auxiliary cylinder apparatus, working machine including same, and use of auxiliary cylinder

A method for using an auxiliary cylinder which is attached to a derricking member of a work machine, the derricking member being capable of making a derricking motion of rotationally moving in a derricking direction, so as to be capable of swing motion about a swing axis parallel to a center axis of the rotational movement in the derricking direction, the auxiliary cylinder being capable of making expansion and contraction motions of expanding and contracting in expansion and contraction directions that are orthogonal to the swing axis, the method comprising:

• installing a fixing device in the work machine, the fixing device being configured to be capable of fixing the auxiliary cylinder to the derricking member only when an expansion length, which is a length of the auxiliary cylinder in the expansion and contraction directions, is within a preset fixing allowing range and configured to release fixing of the auxiliary cylinder when the expansion length is deviated from the fixing allowing range;
• detecting an auxiliary-cylinder angle, which is an angle of the expansion and contraction directions of the auxiliary cylinder to the horizontal direction;
• judging whether or not the auxiliary cylinder is in a predetermined vertical posture, based on the detected auxiliary-cylinder angle;
• and
• performing an expansion control, which is a control of the expansion and contraction motions of the auxiliary cylinder, the expansion control including switching between a fixing state where the auxiliary cylinder is fixed to the derricking member by the fixing device and a fixing release state where fixing of the auxiliary cylinder by the fixing device is released, by causing the auxiliary cylinder to make the expansion and contraction motions when the auxiliary cylinder is in the vertical posture, and prohibiting the auxiliary cylinder from the expansion and contraction motions that deviates the expansion length from the fixing allowing range, when the auxiliary cylinder is in a posture other than the vertical posture in a state where the auxiliary cylinder is fixed to the derricking member by the fixing device.