| 摘要 |
<p>PURPOSE:To reduce the cross-sectional area of a boom of a multi-stage retractable boom device such as that for a high place working vehicle, which can pay out a cable or the like from the proximal end of the boom to the forward end of the boom through the inside of the boom. CONSTITUTION:A boom extending cylinder device 6 is connected between a first boom and a second boom as forward end booms 2. There are provided a coupling member 16 which is coupled to the inner side wall of the rear end part of a third boom 3 at a position below the boom extending cylinder device, and which is extended in the first to third booms 1, 2, 3, substantially parallel with the axis of the boom extending cylinder device, and a second boom extending pulley 15 attached to the rear end of the second boom at a position in rear of the rear end of the boom extending cylinder device, substantially coaxial with the latter, and having a diameter greater than that of the same. With this arrangement, a cable or the like can be vertically laid along the coupling member, the second boom extending pulley 15 and the boom extending cylinder device.</p> |
