2.1) What produces sway?
Trolley does. In other words, trolley’s movement produces sway. Since the hook is suspended from a trolley by a wire, unless there is a movement of the trolley, only the vibration caused by the building or wind could sway the hook.
2.2) What determines the scale of the sway?
Trolley’s speed determines the scale of sway. Thus, when the trolley’s speed is faster, more intense sway is produced.
2.3) Sway and the length of wire (Oscillation)
Once sway is made, it tends to persist with the effect of gravitational force. Thus, the principle of sway is identical to the oscillation principle of a pendulum.
The cycle of sway is determined by L (the length of the wire). When there is the same amount of movement, a shorter wire produces a short cycle of fast movements, and a longer wire produces a long cycle of slow movements.
The simulation results of the change of sway depending upon the length of the wire with the same pattern of operation are described as follows.
-. Length of the wire : 5, 10, 15 meters
-. Speed : 70 m/min
-. Acc: 5 Sec.
-. Dec: 5 Sec
[Figure 2-2] Angular change when the length of the wire is 5 meters.
[Figure 2-3] Angular change when the length of the wire is 10 meters.
[Figure 2-4] Angular change when the length of the wire is 15 meters.
Crane swing?
Today various types of cranes are used to transport materials in many industrial sites.
A wide variety of types are existing depending on the crane’s shape, structure, size, speed, or the connection mechanism.
However, there are common factors that they share: they transport materials by hanging up the objects, and sway occurs inevitably during the process.
A careful operating technique is necessary to reduce the crane operator’s oscillation caused by the sway upon transportation.
Sway is one of the main concerns in the industrial sites in reducing the operation time and preventing safety accidents. To address such issues, we propose an optimal system with the minimized sway by applying C.S.C.S. (Crane Sway Control System) on the overhead traveling crane.
Introduction: Recognizing and detecting the sway
We need to know sway to take control of it. The reason sway is produced, and what factors affect the production of sway is explained in the structure described in Figure [2-1].
Figure [2-1]
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