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MACHINE GUARDING
29 CFR 1910.211-222
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COURSE OBJECTIVES(Continued)
Accident Prevention.
Introduce Machine Guarding and Establish Its Role in Today’s Industry.
Introduce Basic Concepts and Techniques of Machine Safeguarding.
Provide Machine Safeguarding Skills for Maintenance Workers and Floor Supervisors.
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BASIS FOR THIS COURSE
Proper Machine Guarding Results in Accident ReductionElimination of Workplace Injuries & Illnesses Where PossibleReduction of Workplace Injuries & Illnesses Where PossibleDevelopment of Efficient Machine Guarding TechniquesOSHA Safety Standards Require:
Machines Be Properly GuardedTraining Be ConductedHazards and Precautions Be ExplainedA “Safety” Program Be EstablishedJob Hazards Be Assessed and Controlled
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APPLICABLE REGULATIONS
29CFR - Safety and Health Standards1910 - Industrial Safety
212 - General Requirements for All Machines213 - Woodworking Machinery214 - Cooperage Machinery215 - Abrasive Wheel Machinery216 - Mills and Calenders in the Rubber Industry217 - Mechanical Power Presses218 - Forging Machines219 - Mechanical Power Transmission Apparatus
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REMEMBER
Any machine part, function, or process which may cause injury must be safeguarded. When the operation of a machine or accidental contact with it can injure the operator or others in the vicinity, the hazards must be either controlled or eliminated.
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BASICS OF MACHINE GUARDING
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Where Mechanical Hazards Occur
The Point of Operation:Power Transmission Apparatus:Other Moving Parts:
BASICS OF MACHINE GUARDING
Where Mechanical Hazards OccurThe Point of Operation: Where work is performed on the material, such as:
CuttingShapingBoringForming of stock LATHE
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BASICS OF MACHINE GUARDING
Where Mechanical Hazards OccurPower Transmission Apparatus: All components of the mechanical system which transmit energy to the part of the machine performing the work.
300 RPM
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BASICS OF MACHINE GUARDING
Where Mechanical Hazards OccurOther Moving Parts: Any part of the machine which moves while the machine is working.
Rotating partsFeed mechanismsReciprocating partsTransverse moving partsAuxiliary parts of the machine
±±±
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BASICS OF MACHINE GUARDING
Hazardous Mechanical Motions and ActionsA wide variety of mechanical motions and actions may present hazards to the worker:
Rotating membersReciprocating armsMoving beltsMeshing gearsCutting teethAny parts that impact or shear
±±±
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BASICS OF MACHINE GUARDING
Hazardous Mechanical Motions and Actions
Recognition of these hazards is the first step toward protecting workers from the danger they present.
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BASICS OF MACHINE GUARDING
Hazardous Mechanical Motions
Motions
RotatingReciprocatingTransversing NIP POINT
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BASICS OF MACHINE GUARDING
Hazardous Mechanical Actions
Actions
CuttingPunchingShearingBending
SHEARITESHEARITESHEARITECUTTING BLADESCUTTING BLADESCUTTING BLADES
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BASICS OF MACHINE GUARDING
Hazardous Mechanical Motions
Rotating Motions
- Collars - Couplings - Cams- Clutches - Flywheels - Shaft ends- Spindles - Meshing gears - Horizontal shafts- Vertical shafts
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BASICS OF MACHINE GUARDING
Hazardous Mechanical Motions
Rotating Motions
Rotating motions can grip clothing, and through mere skin contact force a limb into a dangerous position. The danger increases when projections such as set screws, bolts, nicks, abrasions, and projecting keys or set screws are exposed on rotating parts.
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BASICS MACHINE GUARDING OF
Hazardous Mechanical Motions
Reciprocating Motions
MOTIONRECIPROCATING
NIP POINT NIP POINT
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BASICS OF MACHINE GUARDING
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Hazardous Mechanical Motions
Reciprocating Motions
MOTIONRECIPROCATING
CAUGHT “IN-BETWEEN”OR “STRUCK-BY”
BASICS OF MACHINE GUARDING
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Hazardous Mechanical Motions
Transversing Motions
TRAVEL
IN-RUNNING NIP POINTS
BASICS OF MACHINE GUARDING
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Hazardous Mechanical Motions
Rotating Motions
NIP POINTS
BASICS OF MACHINE GUARDING
Hazardous Mechanical Actions
Cutting Actions- Rotating motions- Reciprocating motions- Transversing motions
The danger of cutting action exists at the point of operation where finger, arm and bodily injuries can occur and where flying chips or scrap material can strike the head, particularly in the area of the eyes or face.
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BASICS OF MACHINE GUARDING
Hazardous Mechanical Actions
Cutting Actions
BandsawsCircular sawsBoring machinesDrilling machinesTurning machines (lathes)Milling machines
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BASICS OF MACHINE GUARDING
Hazardous Mechanical Actions
Punching ActionsPower pressesIron workers
20 TON
PRESS PRESSACME
PRESSESThe principle hazard occurs at the point of operation where stock is inserted, held or withdrawn.
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BASICS OF MACHINE GUARDING
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Hazardous Mechanical Actions
Shearing/Bending ActionsMechanical shearsHydraulic shearsPneumatic shears
DANGERCUTTING EDGE
PRESS PRESSSHEARITE
POWER SHEARS
SHEAR TERROR
The principle hazard occurs at the point of operation where stock is inserted, held or withdrawn.
BASICS OF MACHINE GUARDING
Requirements for Safeguards
Be securely attachedCreate no new hazardsWithstand operational conditionsAllow for safe routine maintenanceAllow for safe operator adjustmentsWithstand environmental conditionsProvide protection from falling objectsPrevent contact with hazardous conditionsCreate no interference in the conduct of work
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BASICS OF MACHINE GUARDING
Nonmechanical Hazard Considerations:
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Power sources are potential sources of dangerHow will guarding affect equipment operationEnsure proper grounding of systemsReplace frayed, exposed , or old wiringConsider effects of
- High pressure systems- Extreme temp conditions- Pulsation, vibration, or leaks- Noise or unwanted sounds- Cutting fluids and coolants
BASICS OF MACHINE GUARDING
Operator Training Considerations:
Provide instruction and or hands-on trainingDiscuss the purpose of safeguardsCover associated hazards thoroughlyInvolve guard designers in the trainingDescribe how to properly use safeguards Describe how safeguards provide protectionDescribe circumstances for safeguard removalExplain what to do if safeguards are damagedExplain what to do if safeguards are missing
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BASICS OF MACHINE GUARDING
Operator Training Considerations:
Defeating, altering, or removing safeguards can cause injury to co-workers and can leave the person performing such actions liable under the OSHA Act of 1970.
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BASICS OF MACHINE GUARDING
Protective Clothing and Equipment Considerations:
ENGINEERING CONTROLSWork Station Design Tool Selection and DesignProcess Modification Mechanical Assist
ADMINISTRATIVE CONTROLSTraining Programs Job Rotation/EnlargementPacing Policy and Procedures
PERSONNEL PROTECTIVE EQUIPMENT Gloves WrapsShields Eye ProtectionNon-Slip Shoes Aprons
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BASICS OF MACHINE GUARDING
Protective Clothing and Equipment Considerations:
Appropriate for the particular hazard(s)Maintained in good conditionProperly stored when not in useKept clean, fully functional, and sanitary
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METHODS OF MACHINE GUARDING
Guarding Method Dependant on:
Type of materialType of operationMethod of handlingSize or shape of stockPhysical layout of the work areaProduction requirements or limitations
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METHODS OF MACHINE GUARDING
Manufacturers Recommendation:
Before beginning the process of guard procurement, design, or installation, the equipment manufacturer should be consulted for advice.
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METHODS OF MACHINE GUARDING
Generally:
Power transmission apparatus is best protected by fixed guards that enclose the danger areas
Point of operation hazard guarding will vary
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METHODS OF MACHINE GUARDING
Safeguards Are Grouped Under 5 Classifications:
GuardsDevicesLocations/DistanceFeeding and ejection methodsMiscellaneous aids
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METHODS OF MACHINE GUARDING
Guards:
Guards are barriers which prevent access to danger areas, there are four general types:
Fixed guardsInterlocked guardsAdjustable guardsSelf-Adjusting guards
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METHODS OF MACHINE GUARDING
Fixed Guards:
Fixed guards are a permanent part of the machine and not dependent upon moving parts to perform its intended function.
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METHODS OF MACHINE GUARDING
Fixed Guards:
ADVANTAGES
Can be constructed to suit many different applicationsIn-plant construction is often possibleCan provide maximum protectionUsually requires minimum maintenanceCan be suitable to high production operationsCan be suitable to high repetition operations
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METHODS OF MACHINE GUARDING
Fixed Guards:
LIMITATIONS
May interfere with visibilityCan be limited to specific operationsMachine adjustments and repair often require guard removal, thereby necessitating other means of protection for maintenance personnel
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METHODS OF MACHINE GUARDING
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Interlocked Guards:Interlocked guards are designed to automatically shut off or disengage the machine if the guard is opened or removed
AUTOMATICAUDIBLE ALARM
AUTOMATICVISUAL ALARM
METHODS OF MACHINE GUARDING
Interlocked Guards:
Interlocked guards may use:
Electrical powerMechanical powerHydraulic powerPneumatic power
OR ANY COMBINATION OF POWER SOURCES
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METHODS OF MACHINE GUARDING
Interlocked Guards:
Interlocks should not prevent “inching” by remote control if required
Replacing guards should not automatically restart the machine
IMPORTANT
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METHODS OF MACHINE GUARDING
Adjustable Guards:Typically adjusted by the operatorAccommodate various sizes of stockMay require additional operator trainingAdjustable guards are typically used on:
BandsawsTablesawsPower pressesRoutersSimilar equipment
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METHODS OF MACHINE GUARDING
Adjustable Guards:ADVANTAGES
Can be constructed to suit many specific applicationsCan be adjusted to admit varying sizes of stock
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LIMITATIONS
Hands may enter danger areaProtection may not be complete at all timesMay require frequent maintenance and or adjustmentThe guard can be defeated by the operatorMay interfere with visibility
METHODS OF MACHINE GUARDING
Self-Adjusting Guards:Adjusts automatically to the workAccommodate various sizes of stockMay require additional operator trainingSelf-Adjusting guards are typically used on:
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Radial arm sawsTablesawsCircular sawsRoutersJointersSimilar equipment
METHODS OF MACHINE GUARDING
Self-Adjusting Guards:
ADVANTAGES
Off-the-shelf guards are often commercially available
LIMITATIONS
Protection may not be complete at all timesMay require frequent maintenance and or adjustmentMay interfere with visibility
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METHODS OF MACHINE GUARDING
Devices:
Devices fall into four general types:
Presence-Sensing devicesPullback devicesRestraint devicesSafety trip controls
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METHODS OF MACHINE GUARDING
Devices:
Devices may perform one of several function:
Stop a machine if a body part is in dangerRestrain or withdraw a hand if it is in dangerRequire activation by the use of both handsProvide a barrier synchronized to the operation
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METHODS OF MACHINE GUARDING
Presence-Sensing:PhotoelectricRadiofrequencyElectromechanical
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METHODS OF MACHINE GUARDING
Restraint Devices:Uses Cables or StrapsAffixes to HandsMay Need Feeding ToolsAdjustment CriticalPositioning CriticalMaintenance CriticalTraining CriticalMust Restrain Body PartFrom Hazard!
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METHODS OF MACHINE GUARDING
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Safety Trip Controls:Body Trip BarsHand/Arm Trip BarsTripwire CablesPositioning CriticalAdjustment CriticalMaintenance CriticalTraining CriticalManual Reset NeededMust Stop MachineImmediately!
METHODS OF MACHINE GUARDING
20 TON
PRESS PRESSACME
PRESSES
Two-Hand Control:Needs Constant PressureNeeds Concurrent PressurePositioning CriticalAdjustment CriticalMaintenance CriticalTraining ImportantMust Stop MachineImmediately!
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METHODS OF MACHINE GUARDING
Location/Distance Safeguarding:Position Dangerous Areas of Machines So That They Are Not Assessable During Normal Operations. Examples Include:
Position Hazard Areas Against a WallLocate Hazards Out of Reach of OperatorsAdd Enclosures or Fences to Restrict AccessDesign Stock Feeding Openings Away From HazardsPosition the Operators Control Station Away From Hazards
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METHODS OF MACHINE GUARDING
Guard Construction:
Many Machines Come With SafeguardsMany Older Machines Now Have Safeguards AvailableManufacturers Are Increasingly More Concerned With LiabilityCompanies Not Specialized in Guarding Issues
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METHODS OF MACHINE GUARDING
Point-of-Operations Guards :Defined as: “The area on a machine where work is actually
performed upon the material being processed.”
Complicated by the Number and Complexity of Machines in UseMust Fully Safeguard the EmployeeMust Allow Production to ContinueHazard Analysis Is Usually RequiredIf Poorly Designed, Built, or Installed Guards May Create a Hazard Rather Than Eliminating One.
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METHODS OF MACHINE GUARDING
Mechanical Power Transmission Apparatus Guards:
The only openings usually needed are for:
LubricationAdjustmentRepairInspection
300 RPM
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