Mach guard


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  • Welcome to Executive Introduction to ISO 14000. It will help us today if we have an idea of your expertise and experience. ( Note count and write on flip chart ) Please raise your hand if you have been closely involved in getting your company ISO 9000 registered or implementing and maintaining ISO 9000. Please raise your hand if you are the environmental manager or engineer or if you are involved with implementing environmental activities. Please raise your hand if you are the CEO or have management responsibility at your plant site. In the introduction we want to : (1)provide you with information on where you can get assistance and (2) provide you with a “road map to ISO 14000”, that is the big picture, before we get into the details.
  • Prevent Contact - A good safeguarding system eliminates the possibility of the operator or other workers placing parts of their bodies near hazardous moving parts. Secure - A safeguard that can easily be made ineffective is no safeguard at all. Guards and safety devices should be made of durable material that will withstand the conditions of normal use and be firmly secured to the machine. Protect from falling objects - A small tool which is dropped into a cycling machine could easily become a projectile that could strike and injure someone. Create no new hazards - A safeguard defeats its own purpose if it creates a hazard of its own such as a shear point, a jagged edge, or an unfinished surface which can cause a laceration. The edges of guards, for instance, should be rolled or bolted in such a way that they eliminate sharp edges. Create no interference - Any safeguard which impedes a worker from performing a job quickly and comfortably might soon be overridden or disregarded. Proper safeguarding can actually enhance efficiency since it can relieve the worker’s apprehensions about injury. Allow safe lubrication - Locating oil reservoirs outside the guard, with a line leading to the lubrication point, will reduce the need for the worker to enter the hazardous area.
  • In-running nip point hazards are caused by the rotating parts on machinery. There are three main types of in-running nips. Parts can rotate in opposite directions while their axes are parallel to each other. These parts may be in contact (producing a nip point) or in close proximity to each other (where the stock fed between the rolls produces the nip points). This danger is common on machinery with intermeshing gears and rotating cylinders. Another type of nip point is created between rotating and tangentially moving parts; for example, a chain and a sprocket, a rack and pinion, or the point of contact between a power transmission belt and its pulley. Nip points can also occur between rotating and fixed parts which create a shearing, crushing, or abrading action; for example, spoked handwheels or flywheels, screw conveyors, or the periphery of an abrasive wheel and an incorrectly adjusted work rest.
  • 1910.212(a)(2) As a general rule, power-transmission apparatus is best protected by fixed guards that enclose the danger area. For hazards at the point of operation, where moving parts actually perform work on stock, several kinds of safeguarding are possible.
  • An interlocked guard may use electrical, mechanical, hydraulic, or pneumatic power or any combination of these. Interlocks should not prevent “inching” by remote control, if required. Replacing the guard should not automatically restart the machine.
  • Adjustable guards are useful because they allow flexibility in accommodating various sizes of stock, but, because they require adjusting, they are subject to human error.
  • Self-adjusting guards avoid the potential for human error associated with adjustable guards.
  • Tripwire cables must be manually reset to restart the machine.
  • This kind of control requires a part-revolution clutch, brake, and brake monitor if used on a power press as shown. A similar device, known as a two-hand trip , requires concurrent application of both of the operator’s control buttons to activate the machine cycle, after which the hands are free. This device is used with machines equipped with full-revolution clutches. The trips must be placed far enough from the point of operation to make it impossible for the operators to move their hands from the trip buttons or handles into the point of operation before the first half of the cycle is completed to prevent them from being accidentally placed in the danger area prior to the slide/ram or blade reaching the full “down” position.
  • Another potential application of this type of device is where the gate is a component of a perimeter safeguarding system. Here the gate may provide protection not only to the operator but to pedestrian traffic as well.
  • One approach to safeguarding by location is shown in this photo. Operator controls may be located at a safe distance from the machine if there is no reason for the operator to tend it. Another approach is to locate the machine so that a plant design feature, such as a wall, protects the worker and other personnel. Enclosure walls or fences can also restrict access to machines. Another possible solution is to have dangerous parts located high enough to be out of the normal reach of any worker.
  • Many feeding and ejection methods do not require operators to place their hands in the danger area. In some cases, no operator involvement is necessary after the machine is set up. In other situations, operators can manually feed the stock with the assistance of a feeding mechanism. Properly designed ejection methods do not require operator involvement after the machine starts to function. Using feeding and ejection methods does not eliminate the need for safeguarding. Guards and other devices must be used wherever they are necessary to provide protection from hazards. Automatic feeds reduce the operator exposure during the work process, and sometimes do not require any effort by the operator after the machine is set up and running. The power press shown in the photo above has an automatic feeding mechanism. Notice the transparent fixed enclosure guard at the danger area.
  • Robots may create hazards themselves. If they do, appropriate guards must be used. The most common technique is to use perimeter guarding with interlocked gates. The American National Standards Institute (ANSI) safety standard for industrial robots, ANSI/RIA R15.06-1999, presents certain basic requirements for protecting the worker. However, when a robot is used in a workplace, the employer should accomplish a comprehensive operational safety and health hazard analysis and then implement an effective safeguarding system which is fully responsive to the situation. [Various effective safeguarding techniques are described in ANSI B11.19-1990 (R1997).] Studies in Sweden and Japan indicate that many robot accidents did not occur under normal operating conditions, but rather during programming, program touch-up, maintenance, repair, testing, setup, or adjustment. During these operations, workers may temporarily be within the robot’s working envelope where unintended operation could result in injuries.
  • Miscellaneous aids, such as these, do not give complete protection from machine hazards, but may provide the operator with an extra margin of safety.
  • 1910.212(a)(3)(iii)
  • 1910.215(b)(9)
  • Mach guard

    1. 1. 1Subpart O - MachineGuardingOTI 501Paul Schlumper
    2. 2. 2We Will Cover:Machine Guarding PrinciplesSubpart O - HighlightsMock Plant Walk-Through
    3. 3. 3Why are machines not guarded?No one would stick their arm, hand,finger, head, etc. in there.No one is supposed to be back there, inthere, around it while it is running.The machine came that way; it never hada guard.I’ve been doing it this way for twentyyears without any problems.
    4. 4. 4Why are machines not guarded? (cont.)The guard is in the wayThe OSHA inspector didn’t say anythingabout it.We’ll put it back on if OSHA comes.
    5. 5. 5Emphasis on Amputations :Where does it apply?General industry employerswhose workplaces include:shearssawsslicersslitterspower presses(the 4s and a P)
    6. 6. 6Requirements for Safeguards Prevent contact - prevent worker’s body or clothingfrom contacting hazardous moving parts Secure - firmly secured to machine and not easilyremoved Protect from falling objects - ensure that no objects canfall into moving parts Create no new hazards - must not have shear points,jagged edges or unfinished surfaces Create no interference - must not prevent worker fromperforming the job quickly and comfortably Allow safe lubrication - if possible, be able to lubricatethe machine without removing the safeguards
    7. 7. 7Where machine hazards occur:Point of operationMechanical power transmissionOther moving parts
    8. 8. 8Machine Hazards
    9. 9. 9Machine Guarding
    10. 10. 10In-Running Nip PointsBelt andpulleyChain andsprocketRack andpinionRotatingcylinders
    11. 11. 11Methods of machine safeguardingPhysical guardsDevicesLocation/Distance
    12. 12. 12Methods 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 tools
    13. 13. 13GuardsFixedInterlockedAdjustableSelf-adjusting
    14. 14. 14
    15. 15. 15
    16. 16. 16Fixed GuardProvides a barrier - a permanent part of themachine, preferable to all other types of guards.
    17. 17. 17Interlocked GuardWhen this type of guard is opened or removed, thetripping mechanism and/or power automaticallyshuts off or disengages, and the machine cannotcycle or be started until the guard is back in place.Interlockedguard onrevolving drum
    18. 18. 18Adjustable GuardProvides a barrier which may be adjusted tofacilitate a variety of production operations.Bandsaw bladeadjustable guard
    19. 19. 19Self-Adjusting GuardProvides a barrier which moves according tothe size of the stock entering the danger area.Circular table sawself-adjusting guard
    20. 20. 20Safeguarding devicesPresence sensingPullbackRestraintSafety controls and tripsGates
    21. 21. 21
    22. 22. 22
    23. 23. 23Pullback Device Utilizes a series of cablesattached to the operator’shands, wrists, and/or arms Primarily used on machineswith stroking action Allows access to the point ofoperation when the slide/ramis up Withdraws hands when theslide/ram begins to descend
    24. 24. 24Pullback Device (cont’d) Hands in die, feeding Point of operationexposed Pullback device attachedand properly adjusted Die closed Hands withdrawn frompoint of operation bypullback device
    25. 25. 25Restraint Device Uses cables or strapsattached to the operator’shands and a fixed point Must be adjusted to let theoperator’s hands travelwithin a predeterminedsafe area Hand-feeding tools areoften necessary if theoperation involves placingmaterial into the dangerarea
    26. 26. 26Safety Tripwire Cables Device located aroundthe perimeter of or nearthe danger area Operator must be able toreach the cable to stopthe machine
    27. 27. 27Two-Hand Control Requires constant,concurrent pressure toactivate the machine The operator’s hands arerequired to be at a safelocation (on control buttons)and at a safe distance fromthe danger area while themachine completes itsclosing cycle
    28. 28. 28Gate Movable barrier device which protects the operator at thepoint of operation before the machine cycle can be started If the gate does not fully close, machine will not functionGate Open Gate Closed
    29. 29. 29Safeguarding by Location/Distance Locate the machine or itsdangerous moving partsso that they are notaccessible or do notpresent a hazard to aworker during normaloperation Maintain a safe distancefrom the danger area
    30. 30. 30Automatic Feed(shown on power press)TransparentEnclosureGuardStock FeedRollDangerAreaCompleted Work
    31. 31. 31Robots Machines that load andunload stock, assembleparts, transfer objects,or perform other tasks Best used in high-production processesrequiring repeatedroutines where theyprevent other hazards toemployees
    32. 32. 32Protective ShieldsThese do not give complete protection frommachine hazards, but do provide some protectionfrom flying particles, splashing cutting oils, orcoolants.
    33. 33. 33Holding ToolsUsed to place andremove stock in thedanger areaNot to be usedinstead of othermachine safeguards,but as a supplement
    34. 34. 34
    35. 35. 35Subpart O - Machinery and MachineGuarding211 - Definitions212 - General requirements213 - Woodworking machinery215 - Abrasive wheel machinery216 - Mills and calendars217 - Mechanical power presses218 - Forging machines219 - Mechanical power transmission
    36. 36. 361910.212General Requirements for allMachines
    37. 37. 371910.212(a)(1)One or more methods of machineguarding shall be provided to protect theoperator and other employees in themachine area from hazards such as thosecreated by the point of operation, in-going nip points, rotating parts, flyingchips and sparks.
    38. 38. 381910.212(a)(3)(ii)The point of operation of machineswhose operation exposes an employee toinjury, shall be guarded
    39. 39. 391910.212(a)(5)When the periphery of the blades of afan is less than seven (7) feet above thefloor or working level, the blades shall beguarded. The guard shall have openingsno larger than 1/2 inch.
    40. 40. 401910.212(b)Machines designed for a fixed locationshall be securely anchored to preventwalking or moving.
    41. 41. 411910.213Woodworking MachineryRequirements
    42. 42. 421910.213(a)(9)All belts, pulleys, gears, shafts, andmoving parts shall be guarded inaccordance with the specificrequirements of 1910.219.
    43. 43. 431910.213(b)(1)A mechanical or electrical power controlshall be provided on each machine tomake it possible for the operator to cutoff the power from each machine withoutleaving his position at the point ofoperation.
    44. 44. 441910.213(b)(3) On applications whereinjury to the operatormight result if motorswere to restart afterpower failures, provisionshall be made to preventmachines fromautomatically restartingupon restoration ofpower.
    45. 45. 45Table Saws
    46. 46. 461910.213(c)(1)Each circular hand-fed ripsaw shall beguarded by a hood which shallcompletely enclose that portion of thesaw above the table and that portion ofthe saw above the material being cut.The hood and mounting shall bearranged so that the hood willautomatically adjust itself to thethickness of and remain in contact withthe material being cut withoutconsiderable resistance.
    47. 47. 471910.213(c)(2)Each hand-fed circular ripsaw shall befurnished with a spreader to preventmaterial from squeezing the saw or beingthrown back on the operator.
    48. 48. 481910.213(c)(3)Each hand-fed circular ripsaw shall beprovided with non-kickback fingers ordogs so located as to oppose the thrust ortendency of the saw to pick up thematerial or throw it back toward theoperator.
    49. 49. 491910.213(d)(1)Each circular crosscut table saw shall beguarded by a hood which shall meet allthe requirements of 1910.213(c)(1) forhoods for circular resaws.
    50. 50. 50Radial Arm Saws
    51. 51. 511910.213(i)(1)All portions of the saw blade (bandsaws)shall be enclosed or guarded, except forthe working portion of the blade betweenthe bottom of the guide rolls and thetable.
    52. 52. 521910.213(r)(4)The mention of specific machines inparagraphs (a) thru (q) and thisparagraph (r) of this section, inclusive, isnot intended to exclude otherwoodworking machines from therequirements that suitable guards andexhaust hoods be provided to reduce to aminimum the hazard due to the point ofoperation of such machines.
    53. 53. 531910.213(s)(7)All cracked saws shall be removed fromservice.
    54. 54. 541910.215Abrasive-Wheel Machinery
    55. 55. 551910.215(a)(4)Work rests shall be adjusted closely tothe wheel with a maximum opening ofone-eighth inch to prevent the work frombeing jammed between the wheel and therest, which may cause wheel breakage.
    56. 56. 561910.215(b)(9)The distance between the wheelperiphery and the adjustable tongue orthe end of the peripheral member at thetop shall never exceed one-fourth inch.
    57. 57. 571910.215(d)(1)Immediately before mounting, all wheelsshall be closely inspected and sounded bythe user (ring test) to make sure theyhave not been damaged.
    58. 58. 58Abrasive Wheel MachineryThe distance between the wheel periphery and theadjustable tongue must never exceed 1/4-inch.
    59. 59. 591910.217Mechanical Power Presses
    60. 60. 601910.217(a)(5)Press brakes, hydraulic and pneumaticpower presses, bulldozers, hot bendingand hot metal presses, forging pressesand hammers, riveting machines andsimilar types of fastener applicators areexcluded from the requirements of thissection.
    61. 61. 611910.217(b)(4)The pedal mechanism shall be protectedto prevent unintended operation.A pad with a nonslip contact area shallbe firmly attached to the pedal.
    62. 62. 621910.217(b)(6)A two-hand trip shall have the individualoperator’s hand controls protectedagainst unintended operation and bearranged to require use of both hands.Two-hand trip systems on full revolutionclutch machines shall incorporate anantirepeat feature.If two hand trip systems are used onmultiple operator systems, each operatorshall have a separate set of controls.
    63. 63. 631910.217(b)(7)Two-hand controls must incorporate ananti repeat feature, require use of bothhands, be protected against unintendedoperation, have one set of controls foreach operator.If foot control is provided, the selectionbetween hand and foot control must besupervised by the employer.
    64. 64. 641910.217(c)(1)It shall be the responsibility of theemployer to provide and insure the use ofpoint of operation guards or properlyapplied and adjusted point of operationdevices on every operation performed ona mechanical power press. See Table O-10.
    65. 65. 651910.217(e)(1)It shall be the responsibility of theemployer to establish and follow aprogram of periodic and regularinspections of power presses.
    66. 66. 661910.217(e)(3)It shall be the responsibility of theemployer to insure the original andcontinuing competence of personnelcaring for, inspecting, and maintainingpower presses.
    67. 67. 671910.219Mechanical Power-TransmissionApparatus
    68. 68. 681910.219(b)(1)Flywheels located so that any part is 7feet or less above the floor or platformshall be guarded.Wherever flywheels are above workingareas, guards shall be installed havingsufficient strength to hold the weight ofthe flywheel in the event of a shaft orwheel mounting failure.
    69. 69. 691910.219(c)Horizontal, vertical, and inclinedshafting must be enclosed.Projecting shaft ends shall present asmooth edge and end and shall notproject more than 1/2 the diameter of theshaft unless guarded by non rotating capor safety sleeves.
    70. 70. 701910.219(d)Pulleys 7ft. or less above the floor orplatform must be guarded.Pulleys with cracks or pieces broken outof rims shall not be used.
    71. 71. 71Portable Power Tools - General SafetyPrecautions1910.242(a)Employers responsibilitySafe condition of toolsIncluding personal tools1910.242(b)Compressed air not used for cleaning exceptwhere reduced to less than 30 p.s.i. and onlywhen effective chip guarding and PPE.
    72. 72. 72Power ToolsClassification by power sourceElectricPneumaticLiquid FuelHydraulicPowder Actuated
    73. 73. 73Power Tools (cont.) 1910.243 (a)(1) –Portable Circular Saws Upper blade guard Lower blade guardAutomatically returnsto starting position
    74. 74. 74Power Tools (cont.) 1910.243(a)(2) Constant PressureSwitchSaws and Chainsaws Lock-on control(single motionturnoff)
    75. 75. 75Pneumatic Power Tools and Hose1910.243(b)Tool Retainer – A tool retainer must beinstalled on each piece of equipment whereejection could resultAirhose – Hose and hose connections mustbe designed for the pressure and service towhich they are subjected
    76. 76. 76Explosive Actuated Fastening Tools1910.243(d)Must meet requirements in ANSI A10.3-1970Operators and assistants must wear eyeprotectionHead and face protection dependent onworking conditions
    77. 77. 77Explosive Actuated Tools (Cont.)Muzzle must have protective shield orguard at least 3 ½ inches in diameter.Firing must be dependent on at least 2separate and distinct operations.Firing mechanism must prevent toolfrom firing during loading, whilepreparing, if dropped.
    78. 78. 78Explosive Actuated Tools (Cont.)Tools must not be loaded until justbefore intended firing.Do not point at anyone!Fasteners not driven into hard/brittle oreasily penetrable materialTools not used in hazardous atmosphere
    79. 79. 79Lawnmowers243(e)Meet the requirements of ANSI B71.1-X1968