BOOM LOAD-LIFTING CRANE PROTECTION METHOD Russian patent published in 2006 - IPC B66C23/88 B66C13/18 

FIELD: mechanical engineering; load-lifting facilities.

SUBSTANCE: invention relates to method of control and overload protection of boom load-lifting cranes. According to proposed method, tolerable load acting onto boom in longitudinal-vertical plane is determined at designing of crane and is recorded. In process of operation of crane, in case of necessity parameter characterizing current load on boom in longitudinal-vertical plane is measured, and if necessary, changed. Then current load on boom is compared with recorded tolerable one, and signal is shaped to control mechanisms of crane depending on results of comparison. Tolerable value of cross load on boom or twisting load of boom or parameter depending on such load is determined additionally by calculation at designing the crane, and said value is recorded. In process of operation of crane parameter characterizing current cross load on crane boom or boom twisting load is additionally measured and, if necessary, converted. Then tolerable value is compared with current value additionally, and signals to control crane mechanisms are formed. Used as parameter characterizing current cross load on boom or boom twisting load is cross deformation of crane boom or deviation of value of force or torque in crane turning mechanism from nominal value, or difference in forces in horizontally spaced boom wire ropes, or twisting deformation of crane boom, or angle of tilting of boom head in cross plane relative to gravitational vertical or crane slewing platform.

EFFECT: provision of complex overload protection of crane by load torque, cross bend or boom twist.

9 cl, 2 dwg