Keep your “guard” up: Making best use of machine guards 
Working on the production line is like anything else: Do it long enough, and it starts to become second nature. But where heavy machinery is concerned, complacency — the belief that it’s all routine — is your worst enemy. Whether you’ve been on the job 10 years or 10 minutes, personal safety means being aware that the machines you use every day can be dangerous.
In the past six months, Modern Woodworking has reviewed five videos produced by the American Furniture Manufacturers Association addressing safety in the plant. This month, we cover the machine guards used to protect workers from debris, moving parts and electricity. Though machine guards are “worn” by the machines rather than production line workers, they are your first and best lines of defense against injury. Share the following information with your machinery operators.
Staying Alert
Don’t let the rhythm of your work lull you into ignoring potential hazards. Adopting a few good habits can protect you — and your fellow workers — from unpleasant surprises.
Act safely. Learn and closely follow the safety practices for your machine. Learn where potential machine hazards lie. Wear appropriate clothing and protective equipment.
Look for hazards. Use the guidelines below to help spot hazard points on and around your machine. Use safeguards. Learn how the guards on your machine function, and how to use the machine so that the guards are effective. Don’t disable or “go around” a guard, and make sure machine guards are working properly.
Speak up. If you see a hazard that isn’t guarded, a guard that’s not working properly or a guard that’s been disabled, report the hazard to your supervisor. Everybody’s safety is everybody’s concern.
Recognizing Hazards
Improve your hazard-spotting skills by paying attention to these hazard points.
Point of operation. This is the most obvious hazard — the point where the saw blade, drill, shaper, router, knife or other moving tool meets the product. Such tools can pinch or cut a worker, or throw debris such as chips or splinters.
Point of power transmission. Gears, belts, chains and drive shafts — which transfer power from source to tool — are often out of sight and thus out of mind, but there are powerful physical forces at work here.
Machine power sources. Electricity, heat or steam, high-pressure air, hydraulic fluids — all of these power sources represent danger for the worker who accidentally makes contact.
Product feed and take-away machinery. Conveyer belts and similar machines might seem relatively tame, but they can injure the unwary, pinching or snagging fingers, hair, jewelry or clothing.
Other hazards. Take appropriate precautions against hazards such as chemical spray or splash areas and high noise levels. Personal protective equipment can protect you in most instances, but machine guarding, such as shields or enclosures, provides maximum protection.
Know Your Guards
Fixed guards. These guards, which include the housings placed around saw blades, offer maximum effectiveness with minimal maintenance. They are difficult to defeat, but might interfere with the operator’s view of the work and must be removed for maintenance. They also must permit product to pass, which could allow fingers or hands to reach inside the machine.
Interlocked guards. By blocking access to moving machine parts until the machine is completely stopped, interlocked guards provide maximum protection against injury while permitting easy, safe access for maintenance. These guards require regular maintenance and testing, however.
Power loss re-start protection. If power in your plant is temporarily disrupted, a worker might reach into a machine while the power is out to clear product. If power is returned while the worker’s hands are still inside the machine, serious injury could result. Power loss re-start protection ensures that the machine will remain off until the worker turns it back on.
Adjustable guards. The machine operator can adjust these guards to accommodate the product being worked. Good adjustable guards provide excellent protection, although the operator must adjust the guards for each size of product. Self-adjusting guards offer less protection, but are more convenient for the operator.
Enclosure devices. Often, the best protection against injury is to enclose the machine in a room by itself, partitioning it off from the operator via gates or doors. Though not always practical, this type of guard provides maximum protection.
Safety trip controls. The most high-tech of machine guards, safety trip controls include limit switches, pressure-sensitive body bars or mats and photoelectric trip beams. If tripped, these guards will shut down a machine’s moving parts. Safety trip controls require regular maintenance and testing, however, and they offer little protection against flying debris.
Two-hand controls. The principle here is simple: Keep both of the operator’s hands busy, and they can’t end up in the path of moving parts. A machine employing this guard might require the operator to use both hands to engage a saw, knives or other moving parts. This type of guard protects only the operator, so a second guard such as an electric-eye beam may be used.
Distance. Some machines have controls located several feet from the machine itself, or long handles requiring the operator to stand back a few feet to engage the machinery. It’s often easy for workers to defeat such guards, however, so safety trip controls or other backup methods may be desirable.
Semi-automatic or automatic product feed and ejection. Conveyer belts and similar devices protect workers by keeping them away from hazard points. Such devices do create hazards of their own, however, and require regular maintenance.
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