OSHA 10 Hour machine guarding presentation #4


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OSHA 10 hour machine guarding presentation #4

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OSHA 10 Hour machine guarding presentation #4

  1. 1. A good rule to remember is:Any machine part, function, or processwhich may cause injury must besafeguarded.Where the operation of a machine oraccidental contact with it can injure theoperator or others in the vicinity, thehazards must either be eliminated orcontrolled.If it moves, it merits your attention!
  2. 2. Goals1. Describe the basic hazards involving machinery including point of operation and power transmission devices.2. Introduce control measures through effective machine guarding principles and methods.
  3. 3. 1910.212(a)(1) Types of guarding• 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: – Point of operation, – Ingoing nip points, – Rotating parts, – Flying chips and sparks
  4. 4. Point of Operation HazardsThe point where work is actually performed. Cutting Shaping Boring Forming
  5. 5. Part One: The PrinciplesThe purpose of machine guarding is toprotect against and prevent injury from.... Point of operation Nip points
  6. 6. Part One: The PrinciplesThe purpose of machine guarding is toprotect against and prevent injury from.... Point of operation Nip points Rotating parts
  7. 7. Part One: The PrinciplesThe purpose of machine guarding is toprotect against and prevent injury from.... Point of operation Nip points Rotating parts Flying Chips
  8. 8. Part One: The PrinciplesThe purpose of machine guarding is toprotect against and prevent injury from.... Point of operation Nip points Rotating parts Flying Chips Sparks
  9. 9. Where Mechanical Hazards OccurThree basic areas require safeguarding
  10. 10. Where Mechanical Hazards Occur 1. Point of Operation
  11. 11. Where Mechanical Hazards Occur 2. Power Transmission DevicesThe componentswhich transmitenergy to the partof the machineperforming thework.
  12. 12. Where Mechanical Hazards Occur 2. Power Transmission DevicesFlywheels PulleysRods CamsCouplers SpindlesChains SprocketsGears Shafts
  13. 13. Where Mechanical Hazards Occur 3. All Other Moving PartsAll hazardous parts which move while themachine is working. Reciprocating Rotating Transverse Feed mechanisms
  14. 14. Hazardous Mechanical Motions and ActionsA wide variety of mechanical motions andactions may present hazards to theworker. • Rotating or reciprocating members • Moving belts • Meshing gears • Cutting teeth • Any part that impacts or shears
  15. 15. Rotating MotionWhat are some hazards of rotatingparts?
  16. 16. Rotating MotionIn-running nip point hazards1. Parts rotating in opposite direction
  17. 17. Rotating Motion In-running nip point hazards2. Rotating and tangentially moving parts
  18. 18. Rotating MotionIn-running nip point hazards 3. Rotating and fixed parts
  19. 19. Reciprocating MotionTransverse Motion
  20. 20. Standard Interpretations 12/20/1994 - Machine-guarding requirements• By not specifying the types of machine guards that must be used, this standard is referred to as a "performance" standard (i.e., the employer is free to adopt a machine guard that "performs" in such a manner as to meet the standards objective--to protect employees from the identified hazards).• If OSHA had specified the types of machine guards that must be used, the standard would be a "specification" standard.
  21. 21. Effective SafeguardingMust prevent any contact to themachine hazard and installed toprevent contact from around, over,through, or under the guard! “…so designed and constructed as to prevent the operator from having any part of his/her body in the danger zone during the operating cycle” {29 CFR 1910.212(a)(3)(ii)}
  22. 22. Effective Safeguarding• Must be in conformity with any appropriate standards• Must not present a hazard in itself nor create interference
  23. 23. Effective Safeguarding• Must not allow objects to fall into moving parts• Allow safe maintenance and lubrication• Must be affixed and secured to the machine where possible
  24. 24. Part Two: Safeguarding There are many ways to safeguard machines!Determine the appropriate safeguarding method.Consider • the type of operation and material • the size or shape of stock • the method of handling • the physical layout of the work area • production requirements/limitations
  25. 25. Part Two: SafeguardingAs a general rule, power transmission apparatusis best protected by fixed guards that enclose thedanger areas.Enclosed shaftend
  26. 26. Enclosed chain& sprocket
  27. 27. Part Two: SafeguardingFor hazards at the point of operation, severaltypes of safeguarding may be considered.Because safeguarding the point of operationcan provide challenges, one must alwayschoose the most effective and practical meansavailable.Let’s take a look at some strategies
  28. 28. Part Two: Safeguarding1. Guards Fixed Interlocked Adjustable Self-adjusting
  29. 29. Part Two: Safeguarding2. Devices Presence Sensing Pullback Restraint Safety Controls Gates Rockford Systems, Inc.
  30. 30. Part Two: Safeguarding3. Location/Distance4. Feeding/Ejection Methods Automatic/Semi-Auto feed Automatic/Semi-Auto ejection Robotics
  31. 31. Guardwashangingat theworkbench!
  32. 32. Effective?
  33. 33. Effective?
  34. 34. First Safeguarding Strategy: GuardsGuards are barriers which prevent access todanger areas.
  35. 35. First Safeguarding Strategy: GuardsFixed Guards – A permanent part of the machine – Not dependent upon moving parts to perform its intended function – Constructed of sheet metal, screen, wire cloth, bars, plastic, or substantial material – Usually preferable to all other types because of its simplicity and permanence
  36. 36. First Safeguarding Strategy: GuardsInterlocked Guards When this type of guard is opened/removed – the tripping mechanism and/or power automatically shuts off or disengages – the machine cannot cycle or be started until the guard is back in place
  37. 37. First Safeguarding Strategy: GuardsInterlocked Guards – They may use electrical, mechanical, hydraulic, or pneumatic power or any combination of these – Replacing the guard should not automatically restart the machine
  38. 38. Interlocked Guards
  39. 39. Interlockedguardingcan bedefeated!This wastapeddown.
  40. 40. First Safeguarding Strategy: GuardsAdjustable Guards – These guards allow flexibility in accommodating various sizes of stock
  41. 41. First Safeguarding Strategy: GuardsSelf-Adjusting Guards The openings of these guards are determined by the movement of the stock. – As the operator moves the stock into the danger area, the guard is pushed away, providing an opening which is only large enough to admit the stock – After the stock is removed, the guard returns to the rest position
  42. 42. Self-AdjustingGuards
  43. 43. Second Safeguarding Strategy: DevicesA safety device may perform one of severalfunctions. Rockford Systems, Inc.
  44. 44. Second Safeguarding Strategy: DevicesPresence-Sensing Devices Photoelectric (optical) – Uses a system of light sources and controls which can interrupt the machines operating cycle
  45. 45. Second Safeguarding Strategy: Devices • It may stop the machine if a hand or any part of the body is inadvertently placed in the danger area Equipment Resale, Inc
  46. 46. Second Safeguarding Strategy: DevicesPresence-Sensing Devices Radiofrequency (capacitance) – Uses a radio beam that is part of the machine control circuit – When the capacitance field is broken, the machine will stop or will not activate
  47. 47. Second Safeguarding Strategy: DevicesPresence-Sensing Devices Electromechanical – Has a probe or contact bar which descends to a predetermined distance when the operator initiates the machine cycle – If there is an obstruction preventing it from descending its full predetermined distance, the control circuit does not actuate the machine
  48. 48. Second Safeguarding Strategy: Devices • Restrain or withdraw the operators hands from the danger area during operation Rockford Systems, Inc.
  49. 49. Second Safeguarding Strategy: DevicesPullback – Pullback devices utilize a series of cables attached to the operators hands, wrists, and/or arms – This type of device is primarily used on machines with stroking action – When the slide/ram is up between cycles, the operator is allowed access to the point of operation
  50. 50. Second Safeguarding Strategy: DevicesRestraint – The restraint (holdout) device utilizes cables or straps that are attached to the operators hands at a fixed point – The cables or straps must be adjusted to let the operators hands travel within a predetermined safe area - there is no extending or retracting action involved
  51. 51. Second Safeguarding Strategy: Devices • Require the operator to use both hands on machine controls Rockford Systems, Inc.
  52. 52. Second Safeguarding Strategy: DevicesTwo Hand Controls – Requires constant, concurrent pressure by the operator to activate the machine – With this type of device, the operator’s hands are required to be at a safe location (on the control buttons) and at a safe distance from the danger area
  53. 53. Second Safeguarding Strategy: DevicesTwo Hand Trips – This device requires concurrent application of both the operator’s control buttons to activate the machine cycle, after which the hands are free.
  54. 54. Second Safeguarding Strategy: DevicesSafety Trip Controls – Provide a quick means for deactivating the machine in an emergency situation – A pressure-sensitive bar, when depressed, will deactivate the machine
  55. 55. Second Safeguarding Strategy: DevicesSafety Trip Controls – Safety tripwire cables may also be located around the perimeter or near the danger area
  56. 56. Second Safeguarding Strategy: Devices • Provide a barrier which is synchronized with the operating cycle of the machine in order to prevent entry to the danger area during the hazardous part of the cycle Rockford Systems, Inc.
  57. 57. Second Safeguarding Strategy: DevicesGates – A gate is a movable barrier which protects the operator at the point of operation before the machine cycle can be started – Usually designed to operate with each machine cycle
  58. 58. Another Safeguarding StrategyGuarding by Location/Distance – The machine or its dangerous moving parts are positioned so that hazardous areas are not accessible or do not present a hazard during normal operation – walls or other barricades (fences) – height (above worker) – size of stock (single end feeding, punching)
  59. 59. Is this adequate distance?
  60. 60. Is this adequatelocation?
  61. 61. Another Safeguarding StrategyFeeding and Ejection – Automatic and Semiautomatic Feeding
  62. 62. Another Safeguarding StrategyFeeding and Ejection – Automatic Ejection
  63. 63. Another Safeguarding StrategyFeeding and Ejection – Semiautomatic Ejection
  64. 64. Another Safeguarding StrategyRobotics – Machines that load and unload stock, assemble parts, transfer objects, and perform other tasks – They perform work otherwise done by the operator – Best used in high production processes requiring repeated routines
  65. 65. Robotics
  66. 66. Miscellaneous AidsDoes not give complete protection frommachine hazards, but may provide the operatorwith an extra margin of safety. Examples: •Awareness barriers •Shields •Holding tools •Push sticks or blocks
  67. 67. 1910.212(a)(3)(iii) Hand Tools• Special hand tools for placing and removing material shall be such as to permit easy handling of material without the *Such tools shall not be in lieu of other guarding operator placing a hand required by this section, but can only be used to in the danger zone* supplement protection provided.
  68. 68. 1910.212(a)(3)(iv) Examples of machines• Types of machines which normally require point of operation guarding: – Mills – Drills – Grinders – Power presses – Shears – Saws
  69. 69. 1910.212(a)(4) Barrels, containers, and drums• Revolving drums, barrels, and containers shall be guarded by an enclosure which is interlocked with the drive mechanism, so that the barrel, drum, or container cannot revolve unless the guard enclosure is in place
  70. 70. 1910.212(a)(5) Exposure of blades• 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 one-half (1/2) inch.
  71. 71. 1910.212(b) Anchoring fixed machinery• Machines designed for a fixed location shall be securely anchored to prevent walking or moving This pedestal grinder is designed for anchoring, and is not anchored, creating a potential hazard
  72. 72. CPL 2-1.35 National Emphasis Program on Amputations• Identify and reduce workplace hazards likely to cause amputations• top five machines that cause amputations are: – Saws, – Shears, – Slicers, – Slitters, and – Presses.
  73. 73. Saws• Used primarily in woodworking and manufacturing shops• Two types – Table – Radial arm• Other types include: Hand held Band saw Miter saw
  74. 74. Shears• Self-contained machines using a mechanically driven ram• Ram moves a nonrotary blade at a constant rate past the edge of fixed blade
  75. 75. Slicers• Commonly used to slice meat and food• Use rotary blade• Guillotine cutters used in other industries• Most injuries occur in restaurants and grocery stores
  76. 76. Power Presses• NEP covers all types of power presses• Presses consist of stationary bed, and slide• Used in a variety of industries
  77. 77. Program Procedures• NEP includes three • If present, a thorough activities: inspection will be conducted focusing – Outreach on: – Targeting/selection – Nip points – Inspection – Pinch points – Shear points – Cutting actions – Point(s) of operation
  78. 78. 1910.213(a)(12) Guarding blades under tables• For all circular saws where conditions are such that there is a possibility of contact with the portion of the saw either beneath or behind the table, that portion of the saw shall be: – Covered with an exhaust hood, or, if no exhaust system is required, – With a guard that shall be arranged as to prevent accidental contact with the saw
  79. 79. 1910.213(b) Machine controls and equipment• A mechanical or electrical power control shall be provided on each machine to make it possible for the operator to cut off the power from each machine without leaving his position at the point of operation
  80. 80. 1910.213(b)(3) Non-restart devices• On applications where injury to the operator might result if motors were to restart after power failures, provision shall be made to prevent machines from automatically restarting upon restoration of power
  81. 81. 1910.213(b)(4) Location of controls• Power controls and operating controls should be located within easy reach of the operator while he is at his regular work location, making it unnecessary for him to reach over the cutter to make adjustments
  82. 82. 1910.213(c) Ripsaws• Each circular hand-fed ripsaw shall be guarded by a hood which shall completely enclose that portion of the saw above the table and that portion of the saw above the material being cut
  83. 83. 1910.213(c)(2) Spreaders• Each hand-fed circular ripsaw shall be furnished with a spreader to prevent material from squeezing the saw or being thrown back on the operator Spreader
  84. 84. 1910.213(c)(3) Non-kickback fingers• Each hand-fed circular ripsaw shall be provided with non-kickback fingers or dogs so located as to oppose the thrust or tendency of the saw to pick up the material or to throw it back toward the operator
  85. 85. 1910.213(g)(1) Swing cutoff saws• Each swing cutoff saw shall be provided with a hood that will completely enclose the upper half of the saw, the arbor end, and the point of operation at all positions of the saw
  86. 86. 1910.213(g)(2) Swing cutoff saws• Each swing cutoff saw shall be provided with an effective device to return the saw automatically to the back of the table when released at any point of its travel
  87. 87. 1910.213(h) Radial saws• The upper hood completely encloses the upper portion of the blade down to a point that will include the end of the saw arbor• Radial saws used for ripping provided with nonkickback fingers or dogs located on both sides of the saw so as to oppose the thrust or tendency of the saw to pick up the material or to throw it back toward the operator
  88. 88. 1910.213(i) Bandsaws• All portions of the saw blade shall be enclosed or guarded, except for the working portion of the blade between the bottom of the guide rolls and the table
  89. 89. 1910.213(i) Bandsaws• Bandsaw wheels shall be fully encased• The outside periphery of the enclosure shall be solid• The front and back of the band wheels shall be either enclosed by solid material or by wire mesh or perforated metal
  90. 90. Treadle• Each operating treadle shall be covered by an inverted U-shaped metal guard, fastened to the floor, and of adequate size to prevent accidental tripping
  91. 91. 1910.215(a)(2) Guard design• The safety guard shall cover the spindle end, nut, and flange projections• The safety guard shall be mounted so as to maintain proper alignment with the wheel
  92. 92. 1910.215(a)(2) Guard design• The strength of the fastenings shall exceed the strength of the guard, except: – Where the work provides suitable protection, the guard may expose the spindle end, nut and flange – Where the work entirely covers the side of the wheel the side cover(s) of the guard may be omitted
  93. 93. 1910.215(a)(4) Work Rests• On off hand grinding, work rests are required, to support the work• Rigid construction, and adjustable with wheel wear• Must be kept closely adjusted, max gap = 1/8" to prevent work from jamming & breaking wheel Work rest is closely adjusted• Securely clamped after each adjustment•
  94. 94. 1910.215(b)(9) Exposure adjustment• Safety guards of the type where the operator stands in front of the opening, shall be so constructed so that the peripheral protecting member can be adjusted to the constantly decreasing size of the wheel• The distance between the periphery and the adjustable tongue guard shall never exceed one-fourth
  95. 95. 1910.215 (d) Mounting• Inspection: – Immediately before mounting, all wheels shall be closely inspected and sounded by the user (ring test) to make sure they have not been damaged in transit, storage, or otherwise – The spindle speed of the machine shall be checked before mounting of the wheel to be certain that it does not exceed the maximum operating speed marked on the wheel
  96. 96. 1910.215 (d) Mounting -Ring Test • Sound the wheel by tapping around the wheel periphery with a wood handled screwdriver* • Good wheel portions will “ring” like a bell • Cracks will sound “dead” *A non-metallic implement, wood mallets may be needed for larger wheels
  97. 97. 1910.215 (d) Mounting• The spindle speed of the machine shall be checked before mounting of the wheel to be certain that it does not exceed the maximum operating speed marked on Compare this number to the the wheel. spindle speed on the grinder motor
  98. 98. Definitions• "Full revolution clutch" means a type of clutch that, when tripped, cannot be disengaged until the crankshaft has completed a full revolution and the press slide a full stroke.• "Part revolution clutch" means a type of clutch that can be disengaged at any point before the crankshaft has completed a full revolution and the press slide a full stroke.
  99. 99. 1910.217(c)(2) Point of operation guards• It shall prevent entry of hands or fingers into the point of operation by reaching through, over, under or around the guard;• It shall conform to the maximum permissible openings of Table O-10;
  100. 100. Table O-10 [In inches]___________________________________________________ |Distance of opening from point | Maximum width of of operation hazard | opening____________________________ |__________________ | 1/2 to 1 1/2 ................. | 1/4 1 1/2 to 2 1/2 ............... | 3/8 2 1/2 to 3 1/2 ............... | 1/2 3 1/2 to 5 1/2 ............... | 5/8 5 1/2 to 6 1/2 ............... | 3/4 6 1/2 to 7 1/2 ............... | 7/8 7 1/2 to 12 1/2 .............. | 1 1/4 12 1/2 to 15 1/2 ............. | 1 1/2 15 1/2 to 17 1/2 ..........… | 1 7/8 17 1/2 to 31 1/2 ............. | 2 1/8____________________________ |__________________
  101. 101. 1910.217(c)(2) Point of operation guards• Preventing and/or stopping normal stroking of the press if the operators hands are inadvertently placed in the point of operation; Presence sensing device
  102. 102. 1910.217(c)(2) Point of operation guards• Requiring application of both of the operators hands to machine operating controls and locating such controls at such a safety distance from the point of operation that the slide completes the downward travel or stops before the operator can reach into the point of operation with his hands; or
  103. 103. Presence sensing devices• The device may not be used on machines using full revolution clutches!
  104. 104. 1910.217(c)(3)(iv)(d) Pull-out device• Each pull-out device in use shall be visually inspected and checked for proper adjustment at the start of each operator shift, following a new die set-up, and when operators are changed.• Necessary maintenance or repair or both shall be performed and completed before the press is operated.• Records of inspections and maintenance shall be kept in accordance with paragraph (e) of this section.
  105. 105. Pullbackdevice Adjustable wrist straps
  106. 106. 1910.219(b)(1) Flywheels• Flywheels 7 feet or less above the ground shall be guarded• Sheet, perforated, or expanded metal or woven wire, or with• Guard rails between 15 to 20 inches from flywheel rim• Toe board if within 12 inches of floor or extends into a pit• All projections shall be covered
  107. 107. 1910.219.(c) Shafting• Each continuous line of shafting shall be secured in position against excessive end movement• Inclined and vertical shafts* shall be securely held in position against endwise thrust *Particularly inclined idler shafts
  108. 108. 1910.219.(c) Shafting• All exposed parts of horizontal shafting 7 ft. or less above the floor shall be guarded (except: runways used for oiling or running adjustments) by a stationary casing, or by a trough• Troughs must enclose sides and top, or sides and bottom of shafting as location requires
  109. 109. 1910.219.(c) ShaftingProjecting end shafts shall present a smooth edge and project not more than 1/2 the diameter of the shaftUnused key ways shall be filled up or covered
  110. 110. 1910.219(d) Pulleys• Pulleys, any parts of which are seven feet or less from the floor or working platform, shall be guarded in accordance with the standards specified in paragraphs (m) & (o)• Pulleys serving as balance wheels (e.g., punch presses) on which the point of contact between belt and pulley is more than six feet six inches from the floor or platform may be guarded with a disc covering the spokes
  111. 111. ExampleBelt width = three inches Distance between pulleys = 2 inches Guides must be placed in this area
  112. 112. Guard Unguarded portion seven ft. minimumFloor
  113. 113. 1910.219 (f) Gears sprockets and chains• Gears, sprockets and chains shall be guarded by one of the following methods:• By a complete enclosure; or• By a standard guard as in paragraph (o), at least seven feet high, extending six inches above the mesh point of the gears; or