| 摘要 |
PROBLEM TO BE SOLVED: To lower the ground height of a boom device by compacting the boom device used for a concrete pump car in case of housing while smoothly moving the front end of a placing hose by simple operation even at a narrow place in the case of placing operation. SOLUTION: The third boom 10 is divided into the third base-section boom 10A and the third front-section boom 10B while being brought to a bendable state, and the third base-section boom 10A and the third front-section boom 10B are formed in an approximately straight line in case of housing. The third boom 10 is formed in approximately the same length as the length of the second boom 9 under the state of the straight line. The front end of a placing hose 18 can be moved in the approximately horizontal direction even at a narrow place by operating the third cylinder 15 and an auxiliary cylinder 20 in the case of operation.
|
