METHOD OF ADJUSTING OVERLOAD SAFEGUARD Russian patent published in 1996 - IPC

FIELD: load lifting cranes. SUBSTANCE: boom crane has vertical variable-radius swinging boom 3. Safeguard of boom crane has bell crank 1 engaging by one arm with load cable and by other spring-loaded arm acting on limit switch 12. This arm carries two adjusting movable weights 10, 11. Method comes to measuring crane lifting capacity in two extreme positions of its boom. Two measurements are taken. During first measurement second adjusting weight is moved through angle to set it on common vertical with first weight and angular position of vertical relative to longitudinal axis of lever is fixed. Then first weight, together with second weight, is moved along lever in designed position where it is locked and spring effort is adjusted to provide operation of limit switch. During second measurement, preserving previously fixed positions of weights, second weight is moved rectilinearily relative to first weight to make limit switch operate again. Second weight is fixed in this position relative to first weight which makes it possible to fully utilize load lifting capacity of boom crane at different angles of vertical turning of crane boom. EFFECT: enhanced operation reliability and enlarged operating capabilities. 1 dwg