What safety devices should overhead cranes be equipped with?

There are two main types of safety devices for electric overhead cranes: electrical safety devices and mechanical safety devices. Different types play different roles. The main function of the electrical type safety device is to control the circuit. When the crane’s safe behavior is affected, the power supply of the crane is cut off, thereby achieving the safety protection function of the electric bridge crane. The main function of mechanical safety devices is to prevent bridge crane machinery from easily causing failures and to buffer the hazards of crane failures as much as possible when failures occur. The following is a detailed introduction to the safety devices of electric overhead travelling crane and the functions of these safety devices.

Electrical safety devices for overhead cranes

Lighting switch box: It can ensure lighting at the work site and provide better operating sight for electric overhead crane operators.
Electric crane bell: Its main function is to remind the operator below the crane to pay attention to avoidance when the trolley is running, or to remind the hoisting worker that the crane starts to operate.
Stroke limit switch: Its function is to prevent the mechanical overside caused by the motor from causing an accident when the crane reaches the limit or specified location.
Emergency switch: Installed next to the driver’s cab, it allows the driver to cut off the power supply of the control circuit conveniently and quickly in case of an accident or emergency.
Door cabin safety switch: It is installed at the door and hatch to prevent accidents caused by the driver blindly sending power when someone is getting on and off the crane or working on the crane platform.
Anemometer: Its main function is to cut off the power supply when the wind is strong to prevent the electric crane from being blown away by the wind and unable to stop causing safety accidents when working during strong winds. (Mostly assembled on bridge cranes and gantry cranes used in the open air)
Fuse: used to protect the control circuit from short circuit.
Phase sequence protector: It mainly protects the phase sequence of the main power supply. After the crane is debugged, the main power supply cannot be turned around at will, otherwise it will cause the electric crane to run upside down and the limit device to malfunction.
Overcurrent relay: protects the main circuit and motor from overload and short circuit.
The zero position contact of the controller: protects the zero position start and prevents the controller from being able to send power to start when the controller handle is in the working position. An accident may occur if the motor is allowed to run on its own.
Overload limiter: Its main function is to cut off the crane’s rising circuit when the objects lifted by the bridge crane exceed the rated lifting capacity of the crane to ensure the safety of the crane.

Overhead crane mechanical safety device

Railings at various parts: In order to protect the safety of workers and prevent accidents from accidental falls. Railings of no less than 1m are installed on the outside of the platform, end beams and trolleys.
Hook safety card: prevent the wire rope from slipping out of the hook when the crane is lifting objects due to the large distance between the two ends or the large force.
Track end baffles: The end baffles on both sides of the movement of the cart and trolley are to prevent accidents caused by the cart and trolley being offside;
The trolley sliding contact line baffle is to prevent the hook from swinging offside and causing an electric shock accident.
Buffer: Works in conjunction with the end baffle (impact block) to reduce the impact when the car collides with the car, or the car collides with the end point impact block of the track (buffers for cranes are mostly spring-type).
Rail sweeping plate: To prevent foreign objects on the track, there are rail sweeping plates to push foreign objects to both sides.
Protective covers: Rapid transmission shaft guards, hook guards, pulley block guards, etc., to protect the safety of moving parts, ensure the safety of personnel, and prevent collision damage to cast iron parts.
Cab fire extinguisher: a necessary item to prevent circuit fires, usually a powder fire extinguisher.