OSHA Office of Training and Education1MachineMachineGuardingGuardingOSHA Office of Training and Education2IntroductionIntroductionCrushed hands and arms, severed fingers, blindness -the list of possible machinery-related injuries is as long as it is horrifying. Safeguards are essential for protecting workers from needless and preventable injuries.A good rule to remember is: Any machine part, function, or process which may cause injury must be safeguarded.Where the operation of a machine can injure the operator or other workers, the hazard must be controlled or eliminated.OSHA Office of Training and Education3Causes of Machine AccidentsCauses of Machine AccidentsReaching in to “clear” equipmentNot using Lockout/TagoutUnauthorized persons doing maintenance or using the machinesMissing or loose machine guardsOSHA Office of Training and Education4Where Mechanical Hazards OccurWhere Mechanical Hazards OccurPoint of operationAll parts of the machine which move, such as:!flywheels, pulleys, belts, couplings, chains, cranks, gears, etc.!feed mechanisms and auxiliary parts of the machineIn-running nip pointsOSHA Office of Training and Education5Point of OperationPoint of OperationThat point where work is performed on the material, such as cutting, shaping, boring, or forming of stock mustbe guarded.OSHA Office of Training and Education6Rotating PartsRotating PartsOSHA Office of Training and Education7InIn--Running Nip PointsRunning Nip PointsBelt and pulleyChain and sprocketRack and pinionRotating cylindersOSHA Office of Training and Education8Requirements for SafeguardsRequirements for Safeguards Prevent contact - prevent worker’s body or clothing from contacting hazardous moving parts Secure - firmly secured to machine and not easily removed Protect from falling objects - ensure that no objects can fall into moving parts Create no new hazards - must not have shear points, jagged edges or unfinished surfaces Create no interference - must not prevent worker from performing the job quickly and comfortably Allow safe lubrication - if possible, be able to lubricate the machine without removing the safeguardsOSHA Office of Training and Education9Methods of Machine SafeguardingMethods of Machine Safeguarding Guards! fixed! interlocked! adjustable! self-adjusting Devices! presence sensing! pullback! restraint! safety controls (tripwire cable, two-hand contol, etc.)! gates Location/distance Feeding and ejection methods! automatic and/or semi-automatic feed and ejection! robots Miscellaneous aids! awareness barriers! protective shields! hand-feeding toolsOSHA Office of Training and Education10Fixed GuardFixed GuardProvides a barrier - a permanent part of the machine, preferable to all other types of guards.OSHA Office of Training and Education11Interlocked GuardInterlocked GuardWhen this type of guard is opened or removed, the tripping mechanism and/or power automatically shuts off or disengages, and the machine cannot cycle or be started until the guard is back in place.Interlocked guard on revolving drumOSHA Office of Training and Education12Adjustable GuardAdjustable GuardProvides a barrier which may be adjusted to facilitate a variety of production operations.Bandsaw blade adjustable guardOSHA Office of Training and Education13SelfSelf--Adjusting GuardAdjusting GuardProvides a barrier which moves according to the size of the stock entering the danger area.Circular table saw self-adjusting guardOSHA Office of Training and Education14Pullback DevicePullback Device Utilizes a series of cables attached to the operator’s hands, wrists, and/or arms Primarily used on machines with stroking action Allows access to the point of operation when the slide/ram is up Withdraws hands when the slide/ram begins to descendOSHA Office of Training and Education15Pullback Device Pullback Device (cont’d)(cont’d) Hands in die, feeding Point of operation exposed Pullback device attached and properly adjusted Die closed Hands withdrawn from point of operation by pullback deviceOSHA Office of Training and Education16Restraint DeviceRestraint Device Uses cables or straps attached to the operator’s hands and a fixed point Must be adjusted to let the operator’s hands travel within a predetermined safe area Hand-feeding tools are often necessary if the operation involves placing material into the danger areaOSHA Office of Training and Education17Safety Tripwire CablesSafety Tripwire CablesDevice located around the perimeter of or near the danger areaOperator must be able to reach the cable to stop the machineOSHA Office of Training and Education18TwoTwo--Hand ControlHand ControlRequires constant, concurrent pressure to activate the machineThe operator’s hands are required to be at a safe location (on control buttons) and at a safe distance from the danger area while the machine completes its closing cycleOSHA Office of Training and Education19GateGate Movable barrier device which protects the operator at the point of operation before the machine cycle can be started If the gate does not fully close, machine will not functionGate Open Gate ClosedOSHA Office of Training and Education20Safeguarding by Safeguarding by Location/DistanceLocation/Distance Locate the machine or its dangerous moving parts so that they are not accessible or do not present a hazard to a worker during normal operation Maintain a safe distance from the danger areaOSHA Office of Training and Education21Automatic FeedAutomatic Feed(shown on power press)(shown on power press)Transparent EnclosureGuardStock FeedRollDangerAreaCompleted WorkOSHA Office of Training and Education22RobotsRobots Machines that load and unload stock, assemble parts, transfer objects, or perform other tasks Best used in high-production processes requiring repeated routines where they prevent other hazards to employeesOSHA Office of Training and Education23Protective ShieldsProtective ShieldsThese do not give complete protection from machine hazards, but do provide some protection from flying particles, splashing cutting oils, or coolants.OSHA Office of Training and Education24Holding ToolsHolding Tools Used to place and remove stock in the danger area Not to be used instead of other machine safeguards, but as a supplementOSHA Office of Training and Education25Some Examples of OSHA Machine Some Examples of OSHA Machine Guarding
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