general Machine Guarding Machine Guarding Principles Recognizing Hazards Evaluating Hazards Controlling Hazards Subpart O Highlights Employer Responsibilities Employee Responsibilities We Will Cover ID: 767937
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general Machine Guarding
Machine Guarding PrinciplesRecognizing HazardsEvaluating HazardsControlling HazardsSubpart O - HighlightsEmployer ResponsibilitiesEmployee Responsibilities We Will Cover: 2
Why Are Machines Not Guarded?3
No one would ever stick their arm, hand, finger, head, etc. in there.No one is supposed to be back there, in there, around it while it is running.The machine came that way; it never had a guard.I’ve been doing it this way for twenty years without any problems.The guard is in the way.The OSHA inspector didn’t say anything about it. We’ll put it back on if OSHA comes. Why Are Machines Not Guarded? Possible Answers 4
Amputations Can Occur On What Type Of Equipment?5
Power PressesSawsShearsPress BrakesSlicersConveyorsPrinting PressesRoll Forming/Bending MachinesDrill Presses/Milling Machines Amputations Can Occur on the Following Equipment: 6
Where Do Machine Hazards Occur On Equipment?7
Point of operationMechanical power transmissionOther moving partsWhere Machine Hazards Occur: 8
Prevent contactBe secureProtect from falling objectsCreate no new hazardsNo interferenceMaintainability and accessibilityMachine Guarding Requirements 9
Must NOT be able to reach under, through, over or around the guards or otherwise access the hazard!Machine Guarding Requirements Continued 10
Any Hazards? 11
Physical guardsDevicesLocation/DistanceMethods of machine safeguarding 12
FixedInterlockedAdjustableSelf-adjusting Guards vs. Safeguarding Devices Presence sensing Pullback Restraint Safety controls and trips Gates 13
Distance of Opening from Point of Operation (Inches) Maximum Width of Openings (Inches) ½ to 1 ½ ¼ 1 ½ to 2 ½ ⅜ 2 ½ to 3 ½ ½ 3 ½ to 5 ½ ⅝ 5 ½ to 6 ½ ¾ 6 ½ to 7 ½ ⅞ 7 ½ to 12 ½ 1 ¼ 12 ½ to 15 ½ 1 ½ 15 ½ to 17 ½ 1 ⅞ 17 ½ to 31 ½ 2 ⅛ Over 31 ½6 Table 1: Recommended Maximum Openings14
Provides a barrier - a permanent part of the machine, preferable to all other types of guards. Fixed Guard 15
Interlocked guard on revolving drum When 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 16
Bandsaw blade adjustable guard Provides a barrier which may be adjusted to facilitate a variety of production operations. Adjustable Guard 17
Circular table saw self-adjusting guard Provides a barrier that moves according to the size of the stock entering the danger area. Self-Adjusting Guard 18
Presence sensingPullbackRestraintSafety controls and tripsGatesSafeguarding devices 19
Presence Sensing Devices 20
Presence Sensing Device (Light Curtains) 21
Pullbacks and Restraints 22
Two Hand Controls 23
Device located around the perimeter of or near the danger area Operator must be able to reach the cable to stop the machine Safety Tripwire Cables 24
Other Methods 25
Gate Closed Gate Open 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 function Gate 26
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 area Safeguarding by Location/Distance 27
These do not give complete protection from machine hazards, but do provide some protection from flying particles, splashing cutting oils, or coolants. Protective Shields 28
Robot Safety – ANSI/RIA R15.06 2012 29
Fixed Guards (Pros vs. Cons)PROSMany applicationsOften built in-houseCan provide maximum protection Minimal maintenance Suitable for high production, repetitive CONS Can interfere with visibility Can be limited to specific operations (e.g., where point of operation access not necessary) Machine adjustment and repair can require removal, requiring other protection of maintenance 30
Interlocked Guard (Pros vs. Cons)PROSCan provide maximum protectionAllows access for removing jams without time-consuming removal of guards (subject to lockout requirements) CONS Requires careful adjustment and maintenance May be easy to disengage or defeat 31
Presence Sensing (Pros vs. Cons)PROSCan allow more movement for operator into point of operation CONS Limited to machines that can be stopped Does not protect against flying objects May require frequent alignment and calibration 32
Pullbacks/Restraints (Pros vs. Cons)PROSEliminates need for additional guardingSmaller risk of mechanical failure for restraints CONS Limits movement of operator May obstruct work space around operator Adjustments must be made for each operation and individual Requires frequent inspections and maintenance Requires close supervision of the operator 33
2-Hand Control (Pros vs. Cons)PROSOperators hands at a predetermined location (if controls fixed)Operators hands free to pick up parts CONS Requires partial cycle machine with a brake Some 2-hand controls can be defeated Protects only the operator 34
211 - Definitions212 - General requirements213 - Woodworking machinery 215 - Abrasive wheel machinery216 - Mills and calendars217 - Mechanical power presses218 - Forging machines219 - Mechanical power transmission Subpart O - Machinery and Machine Guarding 35
General Requirements for all Machines1910.21236
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 the point of operation, in-going nip points, rotating parts, flying chips and sparks. 1910.212(a)(1) 37
The point of operation of machines whose operation exposes an employee to injury, shall be guarded.1910.212(a)(3)(ii)38
When the periphery of the blades of a fan is less than seven (7) feet above the floor or working level, the blades shall be guarded. The guard shall have openings no larger than 1/2 inch. 1910.212(a)(5) 39
Fans 40
Machines designed for a fixed location shall be securely anchored to prevent walking or moving.1910.212(b)41
Abrasive-Wheel Machinery1910.21542
Work rests shall be adjusted closely to the wheel with a maximum opening of one-eighth inch to prevent the work from being jammed between the wheel and the rest, which may cause wheel breakage. 1910.215(a)(4) 43
Tool Rest Tongue Guard The distance between the wheel periphery and the adjustable tongue or the end of the peripheral member at the top shall never exceed one-fourth inch . 1910.215(b)(9) 44
Source: Idaho State University. Office of Workforce Training Immediately before mounting, all wheels shall be closely inspected and sounded by the user (ring test) to make sure they have not been damaged. 1910.215(d)(1) 45
Mechanical Power Presses1910.21746
Mechanical Power Press 47
Mechanical Full Revolution ClutchCan not be disengaged during full strokeMechanical Part Revolution ClutchCan be disengaged at any time during a full strokeGuarding is dependent on which type of pressExample – Presence sensing devices or two hand controls can’t guard a full revolution – the stroke can’t be disengaged when device is activated Mechanical Power Presses 48
Use of point of operation guards or properly applied and adjusted point of operation devices on every operation performed on a mechanical power press. See Table O-10.1910.217(c)(1) 49
Distance of Opening from Point of Operation (Inches) Maximum Width of Openings (Inches) ½ to 1 ½ ¼ 1 ½ to 2 ½ ⅜ 2 ½ to 3 ½ ½ 3 ½ to 5 ½ ⅝ 5 ½ to 6 ½ ¾ 6 ½ to 7 ½ ⅞ 7 ½ to 12 ½ 1 ¼ 12 ½ to 15 ½ 1 ½ 15 ½ to 17 ½ 1 ⅞ 17 ½ to 31 ½ 2 ⅛ Over 31 ½6 Recommended Maximum Openings50
Periodic and regular inspectionsFoot pedal protected to prevent unintended operationMachine Guarding power transmission apparatus same as other equipmentThe employer must report all point-of-operation injuries within 30 days of occurrenceMechanical Power Presses 51
Mechanical Power-Transmission Apparatus 1910.219 52
Flywheels located so that any part is 7 feet or less above the floor or platform shall be guarded.Wherever flywheels are above working areas, guards shall be installed having sufficient strength to hold the weight of the flywheel in the event of a shaft or wheel mounting failure.1910.219(b)(1) 53
Horizontal, vertical, and inclined shafting must be enclosed.Projecting shaft ends shall present a smooth edge and end and shall not project more than 1/2 the diameter of the shaft unless guarded by non rotating cap or safety sleeves. 1910.219(c) 54
Rotating Shafts and Couplings 55
Rotating Shaft 56
Pulleys 7 ft. or less above the floor or platform must be guarded. Pulleys with cracks or pieces broken out of rims shall not be used. 1910.219(d) 57
Gears 58
What’s wrong with this first picture? 59
What’s wrong with this second picture? 60
What’s wrong with this third picture? 61
What’s wrong with this fourth picture? 62
PORTABLE TOOLS63
1910.242(a)Employers responsibilitySafe condition of toolsIncluding personal tools1910.242(b)Compressed air not used for cleaning except where reduced to less than 30 p.s.i. and only with effective chip guarding and PPE. Portable Power Tools - General Safety Precautions 64
Wooden Hammer 65
1910.243 (a)(1) – Portable Circular SawsUpper blade guardLower blade guardAutomatically returns to starting positionPower Circular Saws 66
1910.243(a)(3)Portable belt sanding machinesGuard nip point where belt runs onto pulleyGuard unused run of belt Power Belt Sanding Machines 67
1910.243(b)Tool RetainerA tool retainer must be installed on each piece of equipment where ejection could resultAir HoseHose and hose connections must be designed for the pressure and service to which they are subjected Pneumatic Power Tools and Hose 68
ACCEPTABLE HOSE C LAMP UNACCEPTABLE Pneumatic Tool Connections 69
Powder Actuated Tools Examples 70
1910.243(d)Must meet requirements in ANSI A10.3-1970Operators and assistants must wear eye protectionHead and face protection dependent on working conditionsPowder Actuated Tools 71
Must have protective shield or guard at least3 ½ inches in diameter.Firing must be dependent on at least 2 separate and distinct operations.Firing mechanism must prevent tool from firing during loading, while preparing, if dropped. Powder Actuated Tools (Cont.) 72
Be sure to use the right size charge with the right size fastener Specific size = Specific operation Fasteners/Charges Used in Powder Actuated Tools 73
In the next couple of slides, look at the photo and indicate whether the equipment is properly guarded or not.If not, what is the hazard and what type of guarding is needed?Guarded or Not Guarded Activity 74
Guarded???? 75
Is this Guarded? 76
Does This Look Guarded? 77
How About Now? 78
Case Study Discussion79
OSHA's websiteStandards, presentations, etc.Machine Guarding e-toolOSHA's Machine Guarding ETool Safeguarding Equipment and Protecting Employees from Amputations https :// www.osha.gov /Publications/osha3170.pdf Georgia Tech's Safety and Health Consultation Program Free, on-site safety and health consultation Completely confidential from OSHA Not from Georgia? There is a consultation program in every state: https ://www.osha.gov/dcsp/smallbusiness/consult.html Sources for Reference 80
Questions? 81