Hydraulic rock-breaking boom for excavator - has inter-articulating jib beam, retro arm and breaker unit controlled by three jacks

摘要

The jib comprises a beam (2), a retro arm (7) and the breaker (9), and is controlled by three jacks. The base of the jib is pinned to the tower (3) of the machine, and the arm extends between pinned joints on the free end of the beam and the breaker. A prim. jack (25) extends between the tower and the free end of the beam. A sec jack (20) controls the inclination of the breaker and extends between the root of the arm and a folding frame (10-18). A third jack (22) extends between the beam and the arm and controls their relative inclination. The connection (21) of the third jack (22) to the arm may locate between the pinned joints to the beam (2) and the breaker (9), and the sec. jack (20) may be positioned inside the arm (7).