Why can't bridge crane stay oblique
The bridge crane is the crane operation must strictly abide by the operation rules, the ten no lifting regulations, the bridge crane operator shall not be inclined to pull oblique lifting, that is, the lifting wire rope through the center of gravity of the lifting object, and maintain vertical, that is, is not allowed to pull oblique lifting. Why not allow diagonal slant?
1. Inclined crane produces inertial force and endangers people around. Inclined lifting objects will produce inertia, easy to decouple and even crisis around the safety of personnel, resulting in safety accidents.
2, inclined crane may overload
Suppose to lift an object of weight Q from the ground, vertical lifting, wire rope tension S is equal to or slightly greater than Q, the weight can leave the ground.
But if it is stayed, the wire rope will be at an Angle to the vertical line of the ground. According to the principle of mechanics, the tension S acting on the wire rope can be decomposed into the force P making the object vertically upward and the force F moving horizontally. In order to make the object lift off the ground, P must be equal to Q at least. And F increases as the Angle between them increases. In other words, the greater the Angle of the slant, the greater the force on the wire rope when lifting the same weight. Therefore, if a heavy load is full when lifting vertically, then it is bound to be overloaded when lifting oblique, and even the steel wire rope will be pulled off the accident.
In addition, the horizontal component F produced by the inclined lifting is also affected by the friction force before the weight leaves the ground. At the moment of leaving the ground, the object will swing to the vertical center, which may cause an accident with the hanging personnel, surrounding operators or other objects.
In a word, if the inclined lifting, not only will cause overload tension wire rope, but also will make the weight swing and squeeze objects and personnel, resulting in personal and equipment accidents.
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