(1) Startweight indicator (angle disc, also known as weight limiter)

The angle of the arm rod root close to the driving position indicates that it will change with the angle of the arm rod, see the angle of the arm rod to the ground, know the angle of the arm rod in different positions, according to the performance table and  curve of the crane, you can learn the amplitude value, lifting weight, lifting height and other reference values at an elevation.

(2) Over-rolling limiter (also known as ultra-high limiter)

A safety device is placed on the end of the arm to limit the lift height of the hook head in order to prevent a roll-up accident. It ensures that when the hook rises to the limit position, it automatically sends an alarm signal or cuts off the power source to stop the rise in order to prevent over-rolling.

(3) Torque Limiter

The torque limiter is a safety device that automatically cuts off the rise or shift power source when the load torque reaches the rated gravity moment, and issues a prohibited alarm signal, and is a limiter to prevent the crane from being unstable due to overloading.

(4) Arm-preventing rear-mounted device and anti-back rod support

The arm-proof rear-up device and the anti-back rod support are safety devices that are no longer lifted when the arm rod rises to the maximum rated elevation, and it prevents the rear tilt of the arm rod when the elevation is too large.