| 摘要 |
PROBLEM TO BE SOLVED: To increase the lifting power without increasing the power of motors for driving drums.SOLUTION: A haulback line 5 of a haulback drum 2 is wound around a fixed pulley 7, and its tip side is connected to a carrier 8 movably supported on an upper overhead line 5a. One end side and the other end side, as a main line 11 and a slack pulling line 12, of a wire material, a longitudinal intermediate part of which is wound around a pair of grooved drums 10a and 10b of a direction conversion drum 10 provided in the carrier 8, are wound around a main drum 3 and a slack pulling drum 4. The carrier 8 comprises a hoisting drum 15 around which a hoist line 16 is wound. An endless chain 19 is wound around driving sprockets 14a and 14b provided in the grooved drums 10a and 10b, respectively, and around a driven sprocket 18 with a larger number of teeth provided in the hoisting drum 15. A rotational drive force given from the slack pulling line 12 to grooved drums 10a and 10b is amplified and transmitted to the hoisting drum 18. |
