Interlocking Guards
Objective: To assure workers understand the types and safe use of interlocking guards
Interlocking guards, also called interlocks, use a tripping mechanism to shut off the machine when a guard or cover is open or removed. They protect workers and coworkers from reaching into moving machinery.
Types of Interlocking Guards
Interlocking guards with:
- Proximity switches use a magnetic field to control machine movement.
- The disadvantage to this type of guard is that any type of metal placed in close proximity to the switch can initiate the starting action.
- Limit switches use a switch to initiate the starting action of machines.
- The disadvantage of this type of guard is that the switch can be easily by-passed.
- A key-activated mechanism is the preferred type of interlock guard, because it is the most difficult system to bypass.
Requirements
- An interlocking guard should be designed so that the machine cannot be operated unless the interlocking guard is in a closed position.
- Interlocking guards must be control reliable, meaning a single component failure will not prevent the stopping action from taking place.
Safe Practices
- Never bypass interlocking guards.
- Assure that the equipment shuts down when the interlocked guard is removed.
- Do not use interlocks as a means for lockout/tagout of equipment.