| 摘要 |
PURPOSE:To enable a piston rod of a trim cylinder to be automatically drawn, in a condition exceeding a trim up position, into said cylinder by operating changeover of a duct selector valve in front and rear of a predetermined tilt up position exceeding a trim up position. CONSTITUTION:After a propelling unit 15 reaches the maximum trim up position, a piston rod 19 of a tilt cylinder 18 reaches the maximum extension position, and a relief valve 63 for a lower chamber is opened, and its hydraulic oil moves a piston 66 of a duct selector valve 58 to set it at the changeover position. After the changeover, hydraulic oil sent into an up side duct 54 is supplied to an upper chamber 29 of a trim cylinder 26 through an upper chamber side duct 57, then hydraulic oil of a lower chamber 30 of the trim cylinder 26 is transferred from a lower chamber side duct 56 to a down side duct 55 to enable a piston rod 27 to be drawn into the trim cylinder 26. |
