What is the change of the tower crane

For the horizontal arm tower crane, the change is the round -trip operation of the trolley with a heavy car lift on the heavy arm. Through the operation of the car, the range of the hook can be adjusted. The car is driven by a variable agency at the root of the arm.
For the moving arm tower crane, the variable amplitude refers to the tower crane the heavy arm itself as a lifting movement to achieve the range of adjusting the hook coverage.

The distance of your tower hanging up heavy arm work