Has balance arm function the tower crane

摘要

PURPOSE: To provide a crane with a balance arm function that is simple in structure and control and inexpensive in cost by keeping the extent of tension in a wire rope from a winch drum constant. ;CONSTITUTION: A winch drum 10 is driven by a constant-torque motor 11 via a speed reducer 12. A load cell 13 is installed in the vicinity of this winch drum 10 of a frame 2, while a pressure measuring sheave 15 is installed in the upper end of a detecting element of this load cell 13, and a wire rope 6 is set to this sheave 15 from the downside. In addition, the load cell 13 is connected to the constant-torque motor 11 via a control panel, and a constant- tension holding means is constituted by the load cell 13 and the constant-torque motor 11. With this constitution, when a hanging load is unloaded, positioning is easily performable by an operator alone.;COPYRIGHT: (C)1994,JPO