The grab crane is an automatic picking machine. Its grabbing and unloading materials are operated by the crane driver and do not need auxiliary personnel, thus avoiding the labor of the workers, saving the auxiliary working time and greatly improving the loading and unloading efficiency. . Grab cranes are generally divided into bridge grab cranes, door grab cranes, and folding arm grab cranes. Usually, grab cranes are referred to as folding arm grab cranes, such as log cranes.
1. Improve production efficiency
For example: before the birth of the grab crane, the dock loading and unloading mineral powder, the ship warehouse
There are 12 to 16 workers, one for each shovel, and one for each group. Each group takes a large leather net bag, and smashes the slag into the big leather net pocket. A net can have up to 4 tons of net. After the net bag is full, it is lifted by a crane. A ship warehouse can only dry up to 200 tons of goods in 8 hours. Nowadays, large unloaders can unload more than 2,000 tons of mine per hour, which greatly provides production efficiency.
2. Improve production safety
For example: before the birth of the grab crane, the dock loading and unloading logs, 4 to 6 workers in the ship's warehouse, first wearing a small wire rope in the gap of the log pile, wearing the estimated area, the two ends of the small wire rope Hanging on the hook of the crane, lifting the distance of 1~2 meters, the one end of the log is tilted up, then the worker takes a 16~28 wire rope, and the front end of the wire rope has a heavy hook, from the neutral of the wooden pile In the past, the workers on the other side quickly caught, otherwise the wire rope would fall into the groove of the wood pile with the hooks, the wire rope workers had to pull up the wire rope and re-twisted, or the workers on the other side used the long wooden sticks with hooks. The tool picks up the wire rope, and then hooks the hook on the wire rope to bind the logs. In the process, the logs may roll and crush the hands and feet of the workers. It is also possible that the workers are overloaded with logs and the ropes are interrupted in the air. Roots or dozens of logs fall into the air and will kill people. Later, Bao Qifan invented the wood grab, which greatly reduced the personal injury accident.
Grab cranes can be classified according to crane type, grab type and driving method. 
According to crane classification
It is divided into bridge grab crane, door grab crane and folding arm grab crane. Can be divided into single beam grab crane and double beam grab crane.
The crane discharges bulk cargo such as coal, ore and phosphate from the cargo hold into the funnel and then to the stacker or loading dock via the conveyor.