How to Choose Safety Protective Devices

In the field of industrial safety protection, there are a variety of protective devices to choose from. Protective devices are also divided into various types, such as fixed guards, movable guards, adjustable guards, and interlocking guards. But according to the different applied scenarios, how to choose the targeted different types of devices? The following can provide you with the main idea about safety fence categories and application scenarios.

• Fixed guards

Fixed guards need to stay in the proper place permanently. For example, the welding and attachable protective devices should rely on the fasteners to be fixed, and they cannot be disassembled or opened without tools, even in the disassembly progress, the fasteners should remain on the guard when the guard is disassembled, and it is impossible not to rely on the fasteners to keep them in place. They’re most often used to enclose the point of operation or other hazards that the operator doesn’t need to interact with, like fan blades or flywheels. Because fixed guards are permanent features of the machine, they must be disassembled and removed to perform any kind of adjustment or maintenance.

• Movable guards: 

Movable guards usually connect with the frame or the nearly fixed parts in mechanical ways like hinges, sliders, etc., and the guards can be opened without tools. It’s clear to notice the shutdown button and the guard would remain in a non-functioning state. The movable guards are mainly used in the area that requires flexibility, like the robot’s working area which would require personnel to enter and adjust.

• Adjustable Guards

Adjustable and self-adjusting guards are used when it is impossible to completely prevent access to dangerous parts. They are commonly used to safeguard woodworking and metalworking machinery where a workpiece must be fed into the machine or manipulated during machine use.

• Interlocking guards

For interlocking guards, the dangerous function of the device equipped by the safety guard can only be operated normally when the safety guard is closed. When the dangerous machine function is being executed, and the guard is opened, the interlocking device would give a shutdown instruction. And the running machine in the hazardous area cannot be self-started just due to the guard closure. This is a high-level safety protective device. In the field of industrial safety, a safety fence with a safety switch can achieve this function.

Safety interlocking guards are divided into two categories according to their different applied scenarios: interlocking movable guards without guard locking and interlocking guards with guard locking. For the interlocking guards with guard locking: The dangerous function of the equipment covered by the guard can only be operated normally after the guard is closed. The guard remains closed and locked until the risk of injury to the dangerous machine function is eliminated. When the guard is closed and in a locked state, the dangerous function of the equipment can be operated, but the closing and locking actions of the guard cannot independently activate the dangerous function of the equipment. In practical application scenarios, safety fences and safety switches with locking functions can achieve this.