| 摘要 |
FIELD: load hoisting and handling equipment. SUBSTANCE: jib crane has support and load jib with hoisting mechanism pivotally mounted on support. Hoisting mechanism includes two drums pivotally installed on common pulling shaft and ropes each wound on its own drum, and also locking device, switch and differential friction unit. Locking device is made as double-action ratchet arrangement having two ratchet wheels with two pawls on one axle conjugating with ratchet wheels on common pulling shaft of drums, and also of switch. Aforesaid switch has pawl switching handle pivotally seated on pawl axle for possible fixed contact with each of pawls, and spring seated in handle. Provision of load hoisting mechanism drive in which two ropes are wound on each own drum, and of drum locking device located between them which switches direction of rope movement for hoisting of lowering or stopping movement, and of differential friction unit which prevents creation of impact loads results in simplified design, reduced overall dimensions and maintaining reliability of load lifting operations. EFFECT: high efficiency. 4 cl, 4 dwg |
