Machine guarding is a basic in anyone's safety education. Even if a person does not work with machinery in an industrial plant, it's important to understand about guards, since these safety devices also prevent contact with the dangerous parts of power tools, landscape equipment and electrical devices. If you plan to discuss machine safety guards with your workers, this safety talk provides a good overview of the subject. A Spanish version of the talk is also available in the Tools section of SafetyXChange.

SAFETY TALK: GUARD AGAINST INJURIES

Machine safety guards have saved many lives and prevented countless injuries by blocking worker contact with moving equipment.

Many industrial machines in use today have safety guards built in by the manufacturer. These guards prevent contact with the point of operation or the mechanical power transmission system.

Sometimes it is necessary to add a guard to the machine if it did not come from the manufacturer with the type of shield required for safe use in a given situation.

Guards prevent worker contact with hazardous machine operations. These operations include the following motions:

• Rotating - such as in-running nip points, spindles, shaft ends and couplings
• Reciprocating - including back-and-forth and up-and-down movements
• Transverse - movement in a continuous straight line

Machine guards are used in operations such as these:

• Cutting with bandsaws, drills, milling machines and lathes
• Punching with punch presses and notching machines
• Shearing with mechanical, compressed air or hydraulic shears
• Bending with tube benders, plate rollers or press brakes

Proper installation and maintenance of machine guards is necessary to ensure they:

• Prevent contact. Guards must prevent the operator or another worker from putting their hands into moving parts.
• Stay secure. Workers shouldn't be able to remove or tamper with a guard easily.
• Protect the machinery from falling objects. Guards should block objects from falling into moving parts.
• Create no new hazards. A machine guard that protects against one hazard but creates another is pointless.
• Cause no serious interference with work. A guard should not create an unacceptable barrier to the worker trying to get the job done.
  

Allow for safe maintenance. It should be possible to lubricate the machine without removing the guard.
Point-of-operation guards have numerous designs because of the many types of machines and the many uses for various machines. Sometimes the manufacturer does not provide a machine guard because one can only be designed after the company using it has made a hazard analysis of the work requirements.

User-built guards sometimes must be added to older machinery. They can be designed and built for unique and changing situations, and even installed on individual stock feeding mechanisms and dies. However, user-built machine guards might not be designed or built as well as those which would have been installed by the manufacturer.

A major difference between point-of-operation guards and mechanical transmission guards is that the latter do not need an opening for feeding stock. The only openings required for power transmission guards are those used to lubricate, adjust, repair or inspect equipment.

Conclusion

If you operate machinery in the workplace, you need to know its hazards and how to protect yourself. Proper use of machine guards is part of your protection. Do not use a machine if the guard is missing or if someone has tampered with it to bypass it or make it ineffective. If you think a guard is needed on a machine even though the manufacturer did not make one, talk to your supervisor. A removable metal framework, sheet metal or wire mesh guard, or a guard of plastic or safety glass might be appropriate to prevent you from connecting with moving parts or flying debris.