Overload protection device can be divided according to their functions automatically stop type, alarm type and integrated type.
Type overload limiter automatically stops when lifting the weight of more than nominal weight, to stop the crane unsafe direction to continue the action, while allowing the crane to a safe direction action. Safety direction refers to a suspension load decreased, contraction arm, and reducing the combined amplitude of these movements. Automatic stop type generally mechanical overload limiter, it is more for the tower crane.
Alarm type overload limiter can show starting weight and weight to be able to play when the alarm rated 95% to 100% by weight of the sound and light signals.
Rated from 95% to 100% by weight of the integrated crane overload limiter can reach crane, audible and visual alarm signal when lifting the weight of more than nominal weight, to stop the continued operation of the crane to unsafe direction.
Overload limiter structure can be divided into mechanical, hydraulic and electronic three types. Mechanical lifting weight limiter has leveraged and bomb-making style and so on.
Overload protection device is designed considering the influence of the load of the crane out, the suspension load in lifting, braking, vibration, the speed change will produce an additional load, dynamic load Chanda lifting the rated load of 110% ~ 130% . Dynamic load lifting operations are inherently dynamic phenomenon, is a feature of lifting machinery operations, so overload protection device designed according to the characteristics of the delay circuit, it has the ability to deal with this false judgment loads, but also to prevent the actual load exceeds a predetermined value, and will not malfunction.