| 摘要 |
PURPOSE:To increase the working range of an excavator and to decrease a slewing radius through a decrease in the working range when slewing is conducted within a tunnel, by a method wherein a boom and an arm are expandably mounted with the aid of each cylinder. CONSTITUTION:A revolvable slewing platform 5 is mounted to the upper part of a self-running vehicle body, a boom 6 is vertically rockably secured to the slewing platform 5, and an expandable boom 7, slid by means of a boom expanding cylinder 9 mounted to the interior of the boom 6, is provided. An arm 10 is pivotally secured to the forward end of the expanding 7 so that it is vertically rockable by means of an arm cylinder 12, and an expanding arm 11, slid by means of an expanding cylinder 15 mounted in the arm 10, is located to the arm 10. A bucket 14 is pivotally fastened to the forward end of an expanding arm 11 so that it is vertically rockable with the aid of a bucket cylinder 13. This enables increasing of a working range, and conversely, this decreases a slewing range. |
