| 摘要 |
A drill boom arrangement comprises a boom proper (10) that is universally pivotably mounted on a support plate (13). The boom is swingable by means of two hydraulic cylinders (16, 17) that are coupled between the support plate and the boom to form a tripod with the boom. The hydraulic cylinders are located on each side of a vertical plane through the boom. A boom head (24) is universally pivotably mounted on the outer end of the boom (10) and it carries a feed beam (40) for a rock drill (41). The boom head is swingable by means of two hydraulic cylinders (27, 28) that are coupled between the boom and the boom head to form another tripod with the boom. These two tripods have similar geometry but the hydraulic cylinders of one tripod is located under the boom and the hydraulic cylinders of the other tripod is located above the boom. The left hand hydraulic cylinder of one tripod is hydraulically coupled in series with the right hand hydraulic cylinder of the other tripod and vice versa so as to provide for parallel displacement of the feed beam when the boom is being swung. |
