| 摘要 |
PROBLEM TO BE SOLVED: To surely prevent an erroneous confirmation of an attitude of machine body and a weight of the machine body performed by an operator during special steering operation. SOLUTION: A first limit switch LS1 detects a forwarded state of an upper part 4 and a horizontal state of a boom. A second limit switch LS2 detects an unloaded state of a counter-weight. An operating switch SW does not work so long as each of the first and second limit switches is not turned on. That is, an interlock mechanism is operated, resulting in that an intermediate shaft S3 can not be lifted up by a lift-up mechanism. In turn, when a specified attitude and a specified weight are detected and each of the limit switches LSI, LS2 is turned on, the operating switch SW is operated and a locked state caused by the inter-lock mechanism is released. |
