Patent ID: 9738498
Date: 2017-08-22
CPC Classifications: B66C

Claim:
1. A telescopic boom extension device comprising: a telescopic boom that includes a base boom, an intermediate boom inserted into the base boom, and a top boom inserted into the intermediate boom, one of the booms adjacent to each other being placed slidably relative to the other boom; a single extension cylinder that includes a cylinder tube and a cylinder rod and that is built into the telescopic boom along a longitudinal direction of the booms while the cylinder rod is coupled to the base boom; a cylinder-boom coupling mechanism that includes a first hydraulic actuator configured to engage selectively with the top boom or the intermediate boom to couple the engaged boom to the cylinder tube; an inter-boom fixing mechanism that includes a second hydraulic actuator configured to couple the adjacent booms to regulate relative sliding of the booms and to decouple specific coupled booms when necessary; and a driving mechanism configured to drive the cylinder-boom coupling mechanism and the inter-boom fixing mechanism, wherein