Machine Guarding Construction

Types of Machine Guards

There are several different types of machine guards. Guards are materials that keep workers from having direct contact with moving parts and other dangerous areas of a machine. Some guards also protect workers from shavings, flying shards or metal sparks created by working machines.Guard design and the material will vary from machine to machine and from tool to tool. The most common types of machine guards are:

• Fixed guards
• Interlocking guards
• Adjustable guards
• Self-adjusting guards

Fixed Guards Fixed guards are permanently attached to the machine or tool, don’t have any moving parts, and can’t be moved while the machine is in use. 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. Adjustable Guards Adjustable guards, like fixed guards, are permanent, but they can be adjusted to allow the machine to handle different sizes of material. They must be manually adjusted and locked into place, so all employees who will operate adjustable guards must be trained on their use. If improperly adjusted or locked, adjustable guards can fail to prevent contact with moving parts, causing serious or even fatal injury. Self-Adjusting Guards Self-adjusting guards serve the same purpose as adjustable guards but automatically adapt to the size of the material. When the machine is at rest, these guards sit all the way down. When the machine is in use, the operator feeds material into the machine, which opens the guard just enough to let the material in. These guards are commonly found on table saws and woodworking tools. Interlocking Guards Interlocking guards, also known as barrier guards, automatically shut off or disengage the power source when the guard is open or removed. These are particularly useful in situations where operators need to be able to open the guard or access the guarded parts of the machine, such as when clearing jams. These guards allow safe access to interior parts of the machine without requiring a total disassembly. However, they can be easy to open on accident and require careful adjustment and maintenance.

General Safety Precautions

To avoid potentially life-threatening injuries, employees should receive proper training before operating any machines or power tools. Employees must never operate machinery without prior training. Employees must:

• Inspect all tools and guards before each use
• Follow all proper lockout/tag-out procedures when necessary
• Use proper procedures when setting up a machine, adjusting a machine, clearing jams, and cleaning or lubricating parts
• Never remove guards while operating a machine
• Tag all damaged guards and machinery “Do Not Use” and report them immediately