Boom extension and contraction mechanism for crane apparatus

摘要

A boom extension and contraction mechanism (30) for a crane apparatus (20) includes: a flow passage switching mechanism (35b) that switches a flow passage of the hydraulic oil between the cylinder-to-boom connection switching cylinder (32b) side and the boom member connection switching cylinder (34b) side; a hose reel (35c) configured to reel out a hydraulic hose (35a) as a telescopic cylinder (31) is extending, and to reel off the hydraulic hose (35a) as the telescopic cylinder (31) is contracting; a cable (37) used to supply power and transmit a signal between a swivel base (21) and a boom (22); and a cord reel (37a) configured to reel out the cable (37) as the telescopic cylinder (31) is extending and to reel off the cable (37) as the telescopic cylinder (31) is contracting. The code reel (37a) and the hose reel (35c) are arranged on the base (21) in a direction in which the boom (22) extends and contracts.