Machine Guards

June 3, 2013 by  
Filed under Uncategorized

The purpose of machine guarding is to protect the machine operator and other employees in the work area from hazards created by:
• Ingoing nip points
• Rotating parts
• Cutting and shearing
• Punching and bending
• Reciprocating and transversing motions
• Flying chips and sparks
Examples of machine guards include:
• Barrier guards
• Light curtains
• Two-hand operating devices
OSHA mandates that machines that expose employees to injury be guarded. The guarding device must conform to any appropriate standards. If specific standards aren’t available, then the machine construction should prevent operators from having any part of their body in the danger zone during the operating cycle
Special hand tools used for placing and removing material from point of operation areas must allow easy handling of the material without the operator placing a hand in the danger zone. Such tools must not replace guards, however.
Point of Operation Guarding
Machines that usually require point of operation guarding include:
• Guillotine cutters
• Shears
• Alligator shears
• Power presses
• Milling machines
• Power saws
• Jointers
• Portable power tools
• Forming rolls and calenders
Revolving barrels, containers, and drums must be guarded by an enclosure interlocked with the drive mechanism, so that the barrel, drum, or container cannot revolve unless the guard enclosure is in place.
Exposure to blades is another situation that requires guarding. When the periphery of the blades of a fan is less than 7 feet above the floor or working level, the blades must be guarded. The guard must not have openings larger than ½ inch

Workplace accidents resulting in amputations are often severe, sometimes disabling, and always preventable.
A moment’s inattention—and a hand is caught in machinery. A single misstep; a foot slips in. Maybe the amputation is immediate, or perhaps the doctors determine later that a limb is too damaged to repair. Either way, it could have been prevented.
Most Hazardous Exposures
Four exposures have been identified by the U.S. Bureau of Labor Statistics as the leading causes of nonfatal workplace amputations:
• Machinery and equipment. The greatest percentage of nonfatal amputations occurs when workers are caught in or crushed by running machinery or equipment, or when they are caught in or crushed by machinery that cycles unexpectedly.
• Parts or materials. The second most common situation that leads to nonfatal amputations occurs when workers are caught in, crushed by, or struck against parts and materials—for example, when a load shifts unexpectedly or stored materials collapse on a worker.
• Vehicles. Motor vehicle accidents are the leading cause of fatal amputations, and the third-leading cause of nonfatal amputations.
• Hand tools. Hand tools, such as handheld circular saws, are the fourth most common cause of nonfatal amputations.
Watch For These Hazards
When you look for amputation hazards on machinery and equipment, remember these hazards:
• Pinch points,where two parts move together and at least one of them is moving in a circle. Pinch points often occur along belt drives, chain drives, gear drives, and feeder rolls.
• Wrap points,where there is an exposed piece of rotating machinery, such as a rotating shaft, especially if it extends beyond bearings or sprockets. Because they can catch clothing or fingers more easily, shafts that are splined, square, or hexagonal are generally more dangerous.
• Shear points,where two moving parts move across each other or a single, sharp edge moves with enough speed or force to cut. Chain or paddle conveyors, trimmers, forklifts, and enclosed augers have shear points.
• Crush points,where two objects are moving toward each other, or one object is moving toward a stationary object. Gears are common crush points.
• Pull-in points,where objects can be pulled into equipment. Feeder rolls or grinders are common pull-in points.
• Thrown objects,hurled by equipment with moving parts. Chippers are known to be common sources of thrown objects.
• 5,260 nonfatal amputations were reported in the United States by private sector employers in 2010. The incidence rate that year was 6 per 100,000 full-time workers.
• The median number of days away from work for those with an amputation was 21 days.
• The majority of amputations (96%) involved a finger.
The industries with the largest number of amputations included production, transportation and material moving, and construction and extraction.

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