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Machine Guards

Moving machine parts must be safeguarded to protect operators from serious injury. Belts, gears, shafts, pulleys, fly wheels, chains, and other moving parts must be guarded if there is a chance they could contact an employee.

As mentioned before, the hazards associated with moving machinery can be deadly. Hazardous areas that must be guarded include the following:

  • Point of operation.
    • The area where the machine either cuts, bends, molds, or forms, the material.
  • Pinch/nip point:
    • Area where moving machine parts can trap, pinch, or crush body parts (e.g., roller feeds, intermeshing gears, metal shears, etc.).
  • Sharp edges
  • Stored potential energy

There are three types of barrier guards that protect people from moving machinery. They consist of the following:

  • Fixed guards
    A fixed guard is a permanent machine part that completely encases potential hazards. Fixed guards provide maximum operator protection.
  • Interlocked guards
    Interlock guards are connected to a machine's power source. If the guard is opened or removed, the machine automatically disengages. Interlocking guards are often preferable because they provide adequate protection to the operator, but they also allow easy machine maintenance. This is ideal for problems such as jams.
  • Adjustable guards
    Self-adjusting guards change their position to allow materials to pass through the moving components of a power tool. These guards accommodate various types of materials, but they provide less protection to the operator.

Guards must be in place. If a guard is removed to perform maintenance or repairs, follow lockout/tag out procedures.

Replace the guard after repairs are completed. Do not disable or move machine guards for any reason. If you notice that a guard is missing or damaged, contact your supervisor and have the guard replaced or repaired before beginning work.

Hand-held power tools typically have less guarding in place than stationary power tools. Use extreme caution when working with hand-held power tools and always wear a face shield.

May 2011
Reviewed November 2014