SLIP PROTECTING DEVICE OF A CRANE

摘要

PURPOSE: A crane slip preventive device and a method thereof are provided to save cost of installation and maintenance and to readily install and maintain by simply embodying the slip preventive device of a wire drum caused by failure of a hoist brake in a bucket crane. CONSTITUTION: A crane slip preventive device comprises a crane main body; a gear reducer driven by a hoist motor; a wire drum(3b) containing wire wound around; a hoist motor(8b) driving the gear reducer; a hoist brake(9b) braking the gear reducer; a subsidiary gear reducer(14a) interlocking with the wire drum; a pig non, and a proximal switch(20a) offering a pulse generated by rotation of the pig non toward a program logic controller(30) and the program logic controller(30) controlling an emergency hydraulic brake during emergency at the same time as controlling actions of each device. Failure of the hoist brake as a brake instrument is sensed and the emergency brake is operated. Thus, an accident of the bucket of crane falling down is avoided in advance.