| 摘要 |
PROBLEM TO BE SOLVED: To provide a bridge type unloader capable of suppressing the excessive rotations of a cotter sheave even if a grab bucket with the cotter sheave is used.SOLUTION: The rotation speed of each drum 40, 50, 60, 70 is made to be predetermined rotation speed. The wind-up amount of a second supporting drum 50 is made to match the wind-up amount of a first supporting drum 40, and the wind-up amount of a first opening/closing drum 60 is made to match the theoretical wind-up amount of the first opening/closing drum 60 calculated from the wind-up amount of the first supporting drum 40 and the second supporting drum 50. The total torque of the first opening/closing drum 60 and a second opening/closing drum 70 is made to be larger than the total torque of the first supporting drum 40 and the second supporting drum 50 by a predetermined amount. The pay-out length of a first opening/closing wire rope 61 or a second opening/closing wire rope 71 has no variation, and tensile force does not differ. Even if a grab bucket 30 with a cotter sheave is used, the excessive rotations of the cotter sheave can be suppressed. |
