| 摘要 |
<p>A large electric dragline having a housing (35) and boom (37) is provided with spaced apart in-line sheaves (34) and (36) at boom point to separate hoist ropes (31) and (32) which are led to the front and rear of bucket (30) respectively. Differential hoist rope control allows accurate and continuous adjustment of the bucket carry angle during all modes of operation. Also described is a computer control system giving continuous accurate control of carry angle by differential hoist rope operation, with manual selection of mode of operation.</p> |
