Machine Guarding
Unsafe machinery is a leading cause of injury in the food industry. Contact with moving machinery parts can result in crushed hands and arms, severed fingers, cuts and lacerations.
Machine guards are used to prevent any possible contact between moving parts of a machine and the worker. They are also used to contain fragments and particles released by a machine.
What Needs to be Guarded
Areas that need guarding include:
- The point of operation: This is the area on a machine where work is actually performed.
- Nip points or pinch points: These are any points where it is possible for a part of the body to be caught between a moving or stationary part of a machinery. For instance two rollers moving counter clockwise to each other create a nip point.
- Powered transmission components: These components include sprockets, chains, flywheels, pulleys, gears, belts, shafts couplings etc.
- Any rotating part of a machine or piece of equipment. Rotating parts can catch hair, loose pieces of clothing, a body part like a finger and pull part or all of the worker into the machine depending upon the size of the machine. Rotating parts can include drive shafts, wheels, revolving drums, or barrels. The projecting end of a rotating shaft also must be guarded.
What is the OSHA Standard
The OSHA law (1910.212) requires that "one or more methods of machine guarding shall be provided to protect the operator and other employees in the machine area from hazards such as those created by point of operation, ingoing nip points, rotating parts, flying chips and sparks." In other words, if any worker can possibly come in contact with any moving part of a machine such as a blade, a sprocket, chain--or can be injured by a flying part - there must be a guard on that machine or machine part.
Types of Machine Guards
Barrier Guard-A guard that is secured to the machine, where possible, and prevents entry of operator's hands or fingers into the point of operation.
Enclosure Guards-completely encloses and prevents access to danger areas. Example is a guard used to enclose belts and pulleys.
Presence Sensing Guards - A guard designed to prevent or stop operation of the machine if a hand or any part of the body is in the danger area. Examples are photo-electrical devices or mechanical-sensing devices.
Two-Hand Trip and Two-Hand Control - Requires concurrent use of both of the operator's hands on control buttons to activate the machine.
Interlocking Guard - This type of guard may or may not be fixed or secured to the machine. This guard cannot be raised while the machine is running, nor can the machine be restarted with the guard in the raised position.
Gates - Provide a barrier that is synchronized with the operating cycle of the machine.
Constant Pressure Switch - Can be used on certain devices like splitter saws. The power is automatically shut off whenever the operator releases controls.
Automatic or semi-automatic feed.
A few important things to remember about machine guards:
- The guard itself should not create a hazard.
- If a guard is on a machine the only time it should be removed is for maintenance and then only after the machine has been locked out and tagged out.
- Guards should be of metal.
- Guards must be firmly attached.
- Guards should be installed so that they cannot be removed easily.
- Guards should create no interference with proper and safe work practices.
- Machines parts should be able to be lubricated without removing the guard.
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