| 摘要 |
The present invention relates to a multi-extendable telescopic boom, extended or contracted such as a vehicle-installed crane or high place working vehicle and, more specifically, to a safety reinforcing device, capable of simply performing hydraulic operation by reducing the number of hydraulic operation members by using a single member of a double-check valve while stably operating a multi-extendable telescopic boom through the double-check valve for interlinking operation between a boom winch and a telescope cylinder after preparing the telescope cylinder, the boom winch, and a boom winch wire for preventing vibrations at the end. The present invention includes a multi-extendable telescopic boom (20), extended or contracted; a hydraulic operation unit; a telescope cylinder (31) extending or contracting the multi-extendable telescopic boom (20); a boom winch (32); and a double-check valve (33) connecting both hydraulic lines injecting fluids of oil pressure into the telescope cylinder (31) and the boom winch (32). The double-check valve (33) operates the boom winch (32) with the oil pressure for operating the telescope cylinder (31). |
