Let everyone know about the overload protection device of lifting machinery

Let us know about the overload protection device of hoisting machinery. Is it the overload protection device of hoisting machinery? What does the crane overload protection device include?
Heavy machinery overload protection device is a device designed to prevent artificial overloading of cranes. Do you know the danger of overloading cranes?
Hazards of Overloaded Crane Operations
Overloading is strictly prohibited in lifting operations. The danger of overloading is very serious. For example, when a crane is overloaded, it will cause the main beam to deflect downward, and the upper cover and web to crack and desolder. Due to the deflection of the main beam, the trolley track will deform along with the main beam. When the trolley drives from the middle of the span to both ends, it not only has to overcome the normal running resistance, but also the additional resistance caused by climbing. In severe cases, the motor of the trolley's operating mechanism is burned out.
The excessive stress generated by the overloaded operation of the crane can cause the wire rope to break, the transmission parts to be damaged, and the motor to burn out. Due to insufficient braking force, the brake cannot hold the brake and a major accident may occur.
Overloading operations are more harmful to jib-type cranes, often causing major accidents in which the jib and tower break. Due to overloading, the stability of the crane is destroyed, and it can also cause a vicious accident in which the entire machine overturns.
Overloading operations will also cause the trolley to slip and roll away on its own, seriously affecting the lifting operation. For double-girder cranes, it will also cause the trolley to run on three legs. Due to horizontal side bends, rail gnawing will occur during small operations.
Introduce the two types of crane overload protection equipment
Lifting weight limiter
If it is used on a bridge type crane, it is used to limit the lifting weight. When the load exceeds the rated lifting weight, use The crane stops lifting upwards and can only move downwards to achieve safety protection.
Torque limiter
The torque limiter is divided into a boom luffing torque limiter and a trolley luffing torque limiter.
For mobile cranes, which generally use booms for luffing, torque limiters are often used for overload protection.
For tower cranes that use trolleys for luffing, lifting weight limiters and torque limiters are generally used to jointly implement overload protection.
Knowledge Expansion What are the common forms of elevator overload protection devices?
The elevator is also a type of crane, and it also needs overload protection. The overload protection devices of the elevator have different types and installation locations. Common overload devices have the following forms: moving car. This overload protection device is widely used, low in price, safe and reliable, but its replacement and maintenance are cumbersome. Rubber pads are usually used as weighing elements, and these rubber elements are fixed between the car chassis and the car frame fixed chassis. When the car is overloaded, the car chassis moves downward under the pressure of the load, causing the rubber pad to deform, triggering the micro switch and cutting off the corresponding control function of the elevator. Generally, there are two micro switches. One micro switch acts when the elevator reaches % load. The elevator is confirmed to be running at full load. The elevator only responds to calls in the car until it reaches the call site. The other micro switch operates when the elevator reaches %. The action occurs when the load is exceeded, the elevator is confirmed to be overloaded, the elevator stops running, the door is kept open, and a warning signal is given. The micro switch is fixed on the movable car chassis through bolts, and the control range of the load capacity can be adjusted by adjusting the bolts.
Move the car floor. This is an overload device installed on the car. There is a certain gap between the movable floor and the car wall. The car floor is supported on the weighing device. As the car floor bears different loads, the floor will move up and down slightly. . When the elevator is overloaded, the movable car floor will sink, turn on the switch, and give the elevator control signal.
Top weighing device. This device uses a compression spring group as a weighing element, and a lever of the overload device is set at the rope head combination of the upper beam of the car frame. When the elevator bears different loads, the rope head combination will drive the lever of the overload device to swing up and down. . When the car is overloaded, the swing of the lever will trigger the micro switch and give the elevator a corresponding control signal.
Room weighing device. When it is inconvenient to install an overload device on both the bottom and top of the car, and the elevator adopts the winding method, we can install the overload device in the machine room. Its structure and principle are similar to the car top weighing device. It is installed on the rope head plate of the machine room, and uses the up and down swing of the rope head plate in the machine room with the elevator load to drive the weighing device lever to swing up and down.
Resistive strain weighing device. The output signals of the above various weighing devices are all switching values. With the continuous development of elevator technology, especially the development of elevator group control technology, it is objectively required that the elevator control system accurately understands the load capacity of each elevator in order to make the elevator The scheduling operation reaches the optimal state. Therefore, traditional switching load signals are no longer suitable for group control technology, and many elevators now use resistance strain weighing devices.
From the crane website./)