What are the safety devices for cranes?

In order to ensure the safety and reliability of the crane, the crane should be equipped with a perfect safety device, in case of accidents, to protect the machine parts or to remind the operator to pay attention to, thus play a safe protective role.
 
1 hydraulic system in the relief valve: can inhibit the abnormal pressure in the circuit to prevent the damage of hydraulic pump and motor, and to prevent overload.
 
2 boom luffing safety device: when the accident occurred, hanging high pressure hose or tubing arm hydraulic cylinder in the loop burst or off when the balance valve in the hydraulic circuit play a role, from the locking cavity of a cylinder oil, the boom will not fall, so as to ensure the safety of operation.
 
3 scalable security device: when the accident occurred, hanging high pressure hose or tubing arm telescopic cylinder in the loop burst or off when the balance valve in the hydraulic circuit play a role, from the locking cavity of a cylinder oil, so that the hanging will retract, so as to ensure the safety of operation.
 
4 height limiting device: hook lifting to a specified height, touch limit weight, open the switch, " around " indicator lamp is bright, and cut off the hook lifting, lifting arm, arm movements and V to ensure safe operation.
 
The 5 leg locking device: when the accident occurred, leading to the vertical leg cylinder high-pressure hose or pipe burst and cutting, the hydraulic system of two-way hydraulic lock can be sealed off the legs of the oil pressure cylinder two chamber, made a leg up or out, so as to ensure the safety of lifting operation.
 
6 weight indicator: closing side weight indicator set in the basic arm, the operator sitting in the control room can be clearly observed, can accurately indicate the arm elevation and the corresponding conditions allow crane rated lifting weight.
 
7 amplitude limiting device; jib luffing crane, should be equipped with a minimum amplitude limiter and the device to prevent the rebound after the arm device. The heavier the trolley, must be equipped with the car trip switch and terminal buffer device.
 
8 rail clamping device and walking limit device: rail type tower crane must be equipped with rail clamping device. At the same time should be equipped with walking limit device.
 
9 anemometer: the root of the arm of the hinge height of more than 50m of the crane, the wind must be installed on the top.
 
10 lightning protection and electromagnetic induction device: the root of the arm of the hinge height of more than 50m of the crane, according to the actual situation should be equipped with lightning protection devices and take measures to prevent electromagnetic interference.
 
11 tower crane in order to prevent the rotating overload should be equipped with limit moment coupling.