WINCHING SYSTEM OF CRANE HAVING EMERGENCY STOPPING DEVICE

摘要

PURPOSE: A winching system of a crane having an emergency stopping device is provided to prevent a falling accident of a load due to a slip of a drum or a variation of the synchronous speeds of a motor and a drum by stopping the winching system after quick and accurate perceiving of the slip and the variation. CONSTITUTION: A winching system of a crane(1) incorporating therein a winching motor(10) for providing winching force to a wire rope for pulling up loads, a speed reducer(20) for reducing or changing the speed of the motor(10), a drum(30) for winching a wire rope thereon, a braker(40) for stopping the rotation of the drum(30) and a controlling panel(50) has an emergency stopping device(100) comprising a motor rotation perceiving part(110) mounted on the motor(10) for perceiving the rotational direction and speed thereof, a drum rotation perceiving part(120) mounted on the drum(30) for perceiving the rotational direction and speed thereof, a comparing part(130) for comparing rotational directions of a driving directions, the motor(10) and the drum(30) and for comparing a speed ratio according to a reduction gear ratio of the motor(10) and the drum(30) with permissible error range and a controlling part(140) for controlling to stop the drum(30) when the rotational directions according to the comparing part(130) are different from each other or the speed ratios escape from the permissible error range, thereby prevents a falling accident of a load.