| 摘要 |
1437885 Rock-drilling ATLAS COPCO AB 10 May 1974 [15 May 1973] 20734/74 Heading B3C [Also in Divisions E1 and G3] In order to ensure that a number of holes are all drilled through earth or rock by a machine 107 to a desired level 103, e.g. the bed of a road under construction, a parallel reference level 102 is established using electromagnetic radiation, e.g. from a rotating laser 101, and drilling is continued until the length D of the hole plus the distance H+K of the level 102 from the point 99 where drilling commences, with possible correction for the drilling angle V, is equal to the height A between the two levels. The reference level 102 is sensed by photo-cells 116 on a telescopic mast 112 which is extended by an hydraulic motor 121, Fig. 2. The distance H is a measure of the height of level 102 above the minimum level of the cells 116, while distance K corresponds to the height of this level above the point 99. The mast may be mounted on the feed beam 106 of the drill or may be freestanding as in Fig. 1. A powered arm 113 then measures the distance K. A binary logic circuit is used to close the hydraulic supply valve of the hammer device of the drill, to stop drilling, when the desired level 103 is reached, the value of A being preset on an electronic counter (14, Figs. 3-5, not shown). |
