| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a telescopic mechanism for expanding and contracting an expansion/contraction boom 10 using one cylinder 1 structured so that a fixing pin of an inter-boom fixing means capable of fixing and removing the booms to/from each other is driven by a fixing pin driving means 40 and capable of hindering such a phenomenon that a drop in oil temperature causes a delay in the actuation of the fixing pin driving means 40 to make longer the total time required for the expansion and contraction of the boom 10. <P>SOLUTION: The control device of the boom telescopic mechanism is composed of a driving pressure control means 130 to control the driving pressure of the fixing pin driving means 40, a fixing pin working speed detection means to detect the working speed of the fixing pin, and a controller. The controller 65 emits a driving pressure signal to the driving pressure control means 130 so that the driving pressure is heightened when the working speed of the driving means 40 is low on the basis of the signal given by the pin working speed detection means, and quickens the actuation by heightening the driving pressure of the driving means 40 in an inter-boom fixing process and an inter-boom releasing process. <P>COPYRIGHT: (C)2004,JPO&NCIPI</p> |
