What Is a Safety Guard?
A safety guard is a piece of safety equipment that restricts entry into a dangerous area. It is a fence that prevents workers from entering the vicinity of processing machines, assembly machines, and rotating equipment that can cause serious accidents if contacted.
In addition to preventing entry into hazardous areas, a safety guard can also serve to contain the dispersion of dust produced during the process and manage the noise generated throughout the processing.
In many cases, safety guards consist of a fence and a door for entry and exit. The base is made of aluminum or iron, and the surrounding area is covered with a mesh or transparent resin such as polycarbonate so that the inside can be seen.
Uses of Safety Guards
Safety guards are used to ensure safety from factory automation (FA) equipment. In the case of specialized machines that greatly improve production efficiency, safety devices are often built into the equipment, and safety guards are not often used. However, in the case of industrial robots, which have been on the increase recently, safety guards are often installed in accordance with the actual environment in which the robot is used and the robot’s movements.
Even in FA systems using cooperative robots, where safety guards are not required, there are cases where safety guards are used to ensure safety because of the danger of end effectors (also called hands) and workpieces coming into contact with people.
Principle of Safety Guards
Safety guards consist of a fence, a door through which people enter and exit, and a safety sensor that checks whether the door is open or closed. Similar to safety guards, there are also sensors called area sensors, which are used to prevent people from entering dangerous areas. Area sensors include area curtains and laser scanners. When a person or object enters a set area, the sensor detects it and activates the safety device.
One aspect that differentiates the use of safety guards and area sensors is visibility. Area sensors rely on infrared light, making it challenging to visually confirm the sensing area. In contrast, a safety guard can prevent accidental entry because the fence itself is visible and the boundary with the danger area can be visually confirmed.
Area sensors have the advantage of being easy to install and inexpensive, but they also have the disadvantage of increasing the risk of unintentional equipment shutdown. Safety guards are used when unexpected equipment stoppage is to be avoided as much as possible.