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Slide 1 (of 185)
ObjectivesObjectives Course No. 204 Machinery and Machine Guarding
Standards Course
• Identify basic machinery terms• Identify common machines found within a
broad spectrum of industries• Identify hazards that occur in or on
machinery• Select the appropriate OSHA STANDARD
that applies to a hazard• Present options to achieve abatement
Slide 2 (of 185)
• The point of operation: that point where work is performed on the material, such as cutting, shaping, boring, or forming of stock.
• Power transmission apparatus: all components of the mechanical system which transmit energy to the part of the machine performing the work. These components include flywheels, pulleys, belts, connecting rods, couplings, cams, spindles, chains, cranks, and gears.
• Other moving parts: all parts of the machine which move while the machine is working. These can include reciprocating, rotating, and transverse moving parts, as well as feed mechanisms and auxiliary parts of the machine.
Dangerous moving parts in these three basic areas need safeguarding:
Slide 3 (of 185)
Rotating pulley
Rotating shaft
Rotating coupling
Burr
Hazardous Rotating Motion
Slide 4 (of 185)
Rotating (including in-running nip points)
Slide 5 (of 185)
Hazardous Reciprocating Motion
Slide 6 (of 185)
Hazardous Transverse Motion
Slide 7 (of 185)
What must a safeguard do to protect workers against
mechanical hazards?
Slide 8 (of 185)
• Prevent contactPrevent contact::
– The safeguard must prevent hands, arms, or any part of a worker's body or clothing from making contact with dangerous moving parts. A good safeguarding system eliminates the possibility of the operator or other workers placing parts of their bodies near hazardous moving parts.
• SecureSecure::
– Workers should not be able to easily remove or tamper with the safeguard, because 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. They must be firmly secured to the machine.
• Protect from falling objectsProtect from falling objects:: – The safeguard should ensure that no objects can fall into moving parts.
A small tool which is dropped into a cycling machine could easily become a projectile that could strike and injure someone.
Slide 9 (of 185)
• Create no new hazardsCreate 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 interferenceCreate no interference::
– Any safeguard which impedes a worker from performing the 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 lubricationAllow safe lubrication::
– If possible, one should be able to lubricate the machine without removing the safeguards. Locating oil reservoirs outside the guard, with a line leading to the lubrication point, will reduce the need for the operator or maintenance worker to enter the hazardous area.
Slide 10 (of 185)
Machine SafeguardingClassifications
Slide 11 (of 185)
• Guards•Fixed• Interlocked•Adjustable•Self-adjusting
• Devices– Presence Sensing
•Photoelectric (optical)
•Radiofrequency (capacitance)
•Electromechanical– Pullback– Restraint
– Safety Controls•Safety trip control
– Pressure-sensitive body bar
– Safety tripod– Safety tripwire
cable• Two-hand control• Two-hand trip
– Gates• Interlocked•Other
Machine Safeguarding Classifications
Slide 12 (of 185)
• Location/Distance• Potential Feeding and
Ejection Methods – Automatic feed– Semi-automatic
feed– Automatic ejection– Semi-automatic
ejection– Robot
Machine Safeguarding Classifications
• Miscellaneous Aids– Awareness
barriers– Miscellaneous
protective shields– Hand-feeding tools
and holding fixtures
Slide 13 (of 185)
Advantages– Can be constructed to suit many
specific applications– In-plant construction is often
possible– Can provide maximum protection – Usually requires minimum
maintenance– Can be suitable to high
production, repetitive operations
Limitations– May interfere with visibility– Can be limited to specific
operations– Machine adjustment and repair
often require its removal, thereby necessitating other means of protection for maintenance personnel
Fixed Guards - Provides a Barrier
Slide 14 (of 185)
Fixed Point of Operation Guard
Slide 15 (of 185)
Safeguarding Action – Shuts off or disengages power and
prevents starting of machine when guard is open; should require the machine to be stopped before the worker can reach into the danger area
Advantages– Can provide maximum protection – Allows access to machine for
removing jams without time-consuming removal of fixed guards
Limitations– Requires careful adjustment and
maintenance– May be easy to disengage
Interlocked
Slide 16 (of 185)
Safeguarding Action – Provides a barrier which may be
adjusted to facilitate a variety of production operations
Advantages– Can be constructed to suit many
specific applications – Can be adjusted to admit varying
sizes of stock
Limitations– Hand may enter danger area -
protection may not be complete at all times
– May require frequent maintenance and/or adjustment
– The guard may be made ineffective by the operator
– May interfere with visibility
Adjustable
Slide 17 (of 185)
Safeguarding Action
– Provides a barrier which moves according to the size of the stock entering danger area
Advantages– Off-the-shelf guards are often
commercially available
Limitations– Does not always provide
maximum protection– May interfere with visibility– May require frequent maintenance
and adjustment
Self-Adjusting
Slide 18 (of 185)
Safety DevicesSafety Devices• Stop the machine if a hand or any part of the
body is inadvertently placed in the danger area;• Restrain or withdraw the operator's hands from
the danger area during operation;• Require the operator to use both hands on
machine controls, thus keeping both hands and body out of danger; or
• 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.
Slide 19 (of 185)
Safeguarding Action – Machine will not start cycling when
the light field is interrupted – When the light field is broken by any
part of the operator's body during the cycling process, immediate machine braking is activated
Advantages– Can allow freer movement for
operator; simplicity of use; no adjustments required
Limitations– Does not protect against mechanical
failure– May require frequent alignment and
calibration– Excessive vibration may cause lamp
filament damage and premature burnout
– Limited to machines that can be stopped
Photoelectric
Slide 20 (of 185)
Safeguarding Action– As the machine begins to cycle, the
operator's hands are pulled out of the danger area
Advantages– Eliminates the need for auxiliary
barriers or other interference at the danger area
Limitations– Limits movement of operator– May obstruct work-space around
operator– Adjustments must be made for
specific operations and for each individual
– Requires frequent inspections and regular maintenance
– Requires close supervision of the operator's use of the equipment
Pullbacks
Slide 21 (of 185)
Safeguarding Action– Prevents the operator from
reaching into the danger area
Advantages– Little risk of mechanical failure
Limitations– Limits movements of operator– May obstruct work-space– Adjustments must be made for
specific operations and each individual
– Requires close supervision of the operator's use of the equipment
Restraint (holdback)
Slide 22 (of 185)
Safeguarding Action
– Stops machine tripped
Advantages– Simplicity of controls
Limitations– Other guards are also required for
operator protection--usually fixed barrier guards
– Requires frequent maintenance – May not be adaptable to stock
variation
Safety Trip Controls
Slide 23 (of 185)
Safety Trip Controls (cont’d)
• When pressed by hand, the safety tripod deactivates the machine.
• Because it has to be actuated by the operator during an emergency situation, its proper position is also critical.
Slide 24 (of 185)
Safety Tripwire Cables Are located around the perimeter of or near the danger area.The operator must be able to reach the cable with either handto stop the machine.
Calender equipped with this type of control.
Slide 25 (of 185)
Safeguarding Action – Concurrent use of both hands is
required, preventing the operator form entering the danger area
Advantages– Operator’s hands are at a
predetermined location– Operator’s hands are free to pick
up a new part after first half of cycle is completed
Limitations– Requires a partial cycle machine
with a brake– Some two-hand controls can be
rendered unsafe by holding with arm or blocking, thereby permitting one-hand operation Protects only the operator
Two Hand Controls
Slide 26 (of 185)
Not Two Hand Controls
Slide 27 (of 185)
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.
• Trips must be placed far enough from the point of operation to make it impossible for the operator to move his or her hands from the trip buttons or handles into the point of operation before the first half of the cycle is completed.
Slide 28 (of 185)
Gate• Movable barrier which protects the operator at the point of
operation before the machine cycle can be started.
Slide 29 (of 185)
Robots
Press
FixedBarrier
Robot
StockConveyor
Slide 30 (of 185)
Miscellaneous
Awareness Barrier
Slide 31 (of 185)
Shields
Slide 32 (of 185)
Part 1910 Subpart O - Machinery and Machine Guarding
• 1910.211 - Definitions.
• 1910.212 - General requirements for all machines.
• 1910.213 - Woodworking machinery requirements.
• 1910.214 - Cooperage machinery. (Reserved)
• 1910.215 - Abrasive wheel machinery.
• 1910.216 - Mills and calenders in the rubber and plastics industries.
• 1910.217 - Mechanical power presses.
• 1910.218 - Forging machines.
• 1910.219 - Mechanical power-transmission apparatus.
Slide 33 (of 185)
Section 1910.212 is a general (or (horizontal) standard that applies to all machines not specifically mentioned elsewhere in other sections of Subpart O. Other sections are specific (vertical) standards that apply to particular types of machines; e.g., Section 1910.213 applies to woodworking machinery.
Horizontal v. Vertical Horizontal v. Vertical
Slide 34 (of 185)
Machine guarding. 1910.212(a)(1)Machine guarding. 1910.212(a)(1)• 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.
Slide 35 (of 185)
1910.212(a)(2)• Guards shall be affixed to the machine where possible and secured
elsewhere if for any reason attachment to the machine is not possible.
•The guard shall be such that it does not offer an accident hazard in itself.
Slide 36 (of 185)
1910.212(a)(3)(ii) The point of operation of machines whose operation exposes an employee to injury, shall be guarded.
Slide 37 (of 185)
1910.212(a)(4)Revolving Drums, Barrels, and Containers
• Must be guarded by an enclosure which is interlocked with the drive mechanism.
Slide 38 (of 185)
1910.212(a)(5) Fan Blades• When the periphery of the blades of a fan is less
than 7 feet above the floor or working level, the blades must be guarded with a guard having openings no larger than ½ inch.
Slide 39 (of 185)
1910.212(a)(6)Anchoring Fixed Machinery– Machines designed for a fixed location must
be securely anchored to prevent walking or moving.
Slide 40 (of 185)
What machines are covered by 910.212
?
Slide 41 (of 185)
Presenting1910.212
Slide 42 (of 185)
OSHA Standards:• 1910.212(a)(1)
Machine guarding• 1910.212(a)(3)(ii)
Point of operation Hazards:
• Contact with pinch points
• Struck by hot metals• Caught in two die
halves Reference Standard: Guarding Method:
• Barrier guard
GatesVideo Clip
Not in Handout
Slide 43 (of 185)
Unguarded Dough Mixer
Slide 44 (of 185)
Ingredient Mixer
OSHA Standards:• 1910.212(a)(1)
Rotating Parts• 1910.212(a)(3)(ii)
Point of operation Hazards:
• Contact with rotating parts
Reference Standard:• ANSI/AHAM FM-1
(food mixers) Guarding Method:
• Interlocks What happened?
• Employee by-passed interlock
Result - Death
Slide 45 (of 185)
Injection Molding Machine
OSHA Standards:• 1910.212(a)(1) Rotating Parts
• 1910.212(a)(3)(ii) Point of operation
Reference Standard:• ANSIB151.1
Guarding Method:• Interlocked barrier gate
GuardedNot Guarded
Slide 46 (of 185)
Injection Molding Machine(Plastic Molding)
1 - Electrical Interlock2 - Hydraulic Interlock
Slide 47 (of 185)
Die Halves Stationary Platen
175 Ton Injection Molding Machine
Interlocked Safety Gate
Mechanical Blocking Mechanism
Slide 48 (of 185)
Injection Molding Machine
3 - Mechanical Blocking MechanismPrevents the dies from closing
Slide 49 (of 185)
OSHA Standards:• 1910.212(a)(1)
Machine guarding• 1910.212(a)(3)(ii)
Point of operation Hazards:
• Contact with pinch points
• Struck by hot metals• Caught in two die
halves Reference Standard:
• Society of Die Cast Engineers – Die Cast Machine Safety)
Guarding Method:• Barrier guard
Die Casting MachinesVideo Clip
Slide 50 (of 185)
Die Casting Operation OSHA Standards:
• 1910.212(a)(1) Nipping points
• 1910.212(a)(3)(ii) Point of operation
Hazard (s):• Stuck-by molten
aluminum• Contact with moving
machine parts Reference Standard:
• Society of Die Cast Engineers – Die Cast Machine Safety
Guarding Method:• Barrier Guard Die Spit Shield
Slide 51 (of 185)
Tubing Bender OSHA Standards:• 1910.212(a)(1) Pinch
Point – Struck by
• 1910.212(a)(3)(ii) Point of operation
Hazard (s):• Caught in the clamp die
• Contact with moving machine parts
Reference Standard:• ANSI B11.15 Pipe Tube
and Shape Bending
Guarding Method:• Barrier guard
• Foot pedal operation
• Presence sensing device
Slide 52 (of 185)
Swing Arm in Motion
Slide 53 (of 185)
Addison Tube Bender
Safety Matand
Foot Pedal Control
Slide 54 (of 185)
Mechanical Power Press Brake
OSHA Standards:• 1910.212(a)(3)(ii) Point of
operation Hazards:
• Caught in the point of operation
Reference Standard:• ANSIB11.3 Power Press Brakes
Guarding Method:• Presence Sensing Devices• Two hand controls• Automatic barrier gates• Restraint device
Slide 55 (of 185)
Point of operation hazard – CPL 2-1.25Guidelines for point of operation guarding forpower press brakes
4 4 inchesinches 4 “
Slide 56 (of 185)
Press Brake Foot Treadle OperatedWith a Restraint Device
Slide 57 (of 185)
Photo electric sensingacross face and barrieracross the ends of the press brake
Press brake
Slide 58 (of 185)
The Back of The Press Brake
Awareness Guard
Slide 59 (of 185)
Horizontal Metal Cutting Band Saw
OSHA Standards:• 1910.212(a)(1) Machine
Guarding Hazards:
• Contact with the unused portion of the saw blade
Reference Standard:• ANSIB11.10 Sawing
Guarding Method:• Telescoping barrier guard
Slide 60 (of 185)
Metal Cutting Radial Saw
OSHA Standards:• 1910.212(a)(3)(ii) Point of
operation guarding Hazards:
• Contact with the saw blade
Reference Standard:• ANSIB11.10 Sawing
Guarding Method:• Side barrier guard
Slide 61 (of 185)
OSHA Standards:• 1910.212(a)(1)
Nipping point Hazards:
• Contact with rotating parts
Reference Standard:• ANSI B20.1
Conveyors Guarding Method:
• Barrier guard• Isolation• Control relocation
Meat auger
Slide 62 (of 185)
Guard does not meet requirement of Table O-10
Screw Conveyor
Slide 63 (of 185)
OSHA Standards:• 1910.212(a)(3)(ii) Point of
operation guarding Hazards:
• Contact between the forming rolls and the material
Reference Standard:• ANSIB11.12 Roll forming and Roll
Bending Guarding Method:
• Barrier guard (interlocked)• Presence sensing device
Forming Mill Table
May use safety trip wire???
Slide 64 (of 185)
Forming Mill
In-running Nip Point
Point of Operation
Slide 65 (of 185)
Forming Mill
Shows the process of metal forming – Metal is being pulled through dies and formed as it progresses.
Slide 66 (of 185)
OSHA Standards:• 1910.212(a)(1) Machine
guarding Hazards:
• Contact between the belt and the pulley nip (drum)
Reference Standard:• ANSIB 20.1 Conveyors
Guarding Method:• Barrier guard • Isolation
Back of a Shear – Material Take-off Conveyor
Slide 67 (of 185)
Nip Point
Conveyor Nip
Slide 68 (of 185)
Scissor Lift Table
OSHA Standards:• 1910.212(a)(1) Machine
guarding Hazards:
• Contact between the scissors arms
Reference Standard:• ??
Guarding Method:• Telescoping barrier guard • Isolation
Slide 69 (of 185)
Pyramid or Pinch Roll Forming
OSHA Standards:• 1910.212(a)(3)(ii) Point of
operation guarding Hazards:
• Contact in the point of operation
Reference Standard:• ANSI B11.12 Roll forming and
bending Guarding Method:
• Isolation• Limited barrier guards
Slide 70 (of 185)
Pyramid or Pinch Roll Forming
Point of OperationPoint of Operation
Slide 71 (of 185)
Roll Former Isolation Guarding
Slide 72 (of 185)
REELPaper Mill Pope
OSHA Standards:• 1910.212(a)(3)(ii) Point of
operation guarding Hazards:
• Contact in the point of operation
Reference Standard:• ANSI B11.12 Roll forming and
bending Guarding Method:
• Isolation• Limited barrier guards
Slide 73 (of 185)
REEL – Threading the MachinePaper Mill Pope
In Running Nip Point
Slide 74 (of 185)
REEL – Threading the MachinePaper Mill Pope
Slide 75 (of 185)
REELPaper Mill Pope
Slide 76 (of 185)
REELPaper Mill Pope
Slide 77 (of 185)
Primary Arm Guard
Slide 78 (of 185)
Lathe
OSHA Standards:• 1910.212(a)(1)
Rotating parts Hazards:
• Contact with rotating parts
Reference Standard:• ANSI B11.6 Lathes
Guarding Method:• Barrier guard
Slide 79 (of 185)
Lathe
Slide 80 (of 185)
Lathe Chip Shield
Slide 81 (of 185)
Tapper
OSHA Standards:• 1910.212(a)(1) Machine guarding• 1910.212(a)(3)(ii) Point of operation
guarding Hazards:
• Contact with rotating parts, chips and coolant
• Contact in the point of operation
Reference Standard:• ANSI B11.8 Tapper
Guarding Method:• Barrier guards and/or isolation
Slide 82 (of 185)
Vertical Boring Mills
OSHA Standards:• 1910.212(a)(1) Machine
guarding Hazards:
• Contact with rotating parts
Reference Standard:• ANSI B11. 8 Milling, drilling and
boring machines Guarding Method:
• Barrier guards
Slide 83 (of 185)
Vertical Boring Mills
Slide 84 (of 185)
Vertical Boring MillChip, and Rotating Part Guard
Slide 85 (of 185)
Horizontal Boring Mill
Slide 86 (of 185)
Mechanical Shear
OSHA Standards:• 1910.212(a)(1) Machine guarding• 1910.212(a)(3)(ii) Point of operation
guarding Hazards:
• Contact with shear blade• Contact with hold down
Reference Standard:• ANSI B11. 4 Shears
Guarding Method:• Barrier guard
Hold down
Slide 87 (of 185)
Shear in Operation
Helper is exposed
Slide 88 (of 185)
Modified Guard
Hydraulic Shear
Blade
Slide 89 (of 185)
OSHA Standards:• 1910.212(a)(1)
Machine guarding• 1910.212(a)(3)(ii)
Point of operation Hazards:
• Contact with mold halves
• Contact with shuttle Guarding Method:
• Barrier guards• Presence devices
Core Making MachinesVideo Clip
Slide 90 (of 185)
Iron Worker OSHA Standards:• 1910.212(a)(1)
Machine guarding• 1910.212(a)(3)(ii)
Point of operation Hazards:
• Contact with angle shear or notcher
• Contact with the punch and die
Guarding Method:• Barrier guards
Slide 91 (of 185)
Woodworking Machinery Requirements
1910.213
Slide 92 (of 185)
• 10.213(a)(9) All belts, pulleys, gears, shafts, and moving parts must be guarded in accordance with the specific requirements of 1910.219.
Belts
Slide 93 (of 185)
• Circular table saws must have Circular table saws must have a hooda hood over the portion of the saw above the table, so mounted that the hood will automatically adjust itself to the thickness of and remain in contact with the material being cut.
• Must have a spreaderMust have a spreader aligned with the blade, spaced no more than one-half inch behind the largest blade mounted in the saw.
• If used for rippingIf used for ripping must have nonkickback fingers or dogs.
1910.213(c) Rip Saws
Slide 94 (of 185)
1910.213(d) Hand fed Crosscut SawShall Meet Requirements of (c)(1)
Slide 95 (of 185)
• 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.
• Constructed in such a manner and of such material that it will protect the operator from flying splinters and broken saw teeth.
• Automatically cover the lower portion of the blade, so that when the saw is returned to the back of the table the hood will rise on top of the fence, and when the saw is moved forward the hood will drop on top of and remain in contact with the table or material being cut.
10.213(g) Swing Cutoff Saws
Slide 96 (of 185)
Slide 97 (of 185)
Slide 98 (of 185)
1910.213 (h) Radial Saws• Upper hoodUpper hood that completely enclose the
upper portion of the blade down to a point that will include the end of the saw arbor.
• Sides of the lower exposed Sides of the lower exposed portionportion of the blade guarded to the full diameter of the blade.
• Radial saw used for rippingRadial saw used for ripping shall be provided with nonkickback fingers or dogs .
• Adjustable stopAdjustable stop to prevent the forward travel of the blade beyond the position necessary to complete the cut in repetitive operations.
• Installation such that the front Installation such that the front endend of the unit will be slightly higher than the rear, so as to cause the cutting head to return gently to the starting position when released by the operator.
Slide 99 (of 185)
Radial Arm Saws
Slide 100 (of 185)
Slide 101 (of 185)
1910.213 (i) Bandsaws andBand Resaws• 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.
• Wheels fully encased.
• Outside periphery of the enclosure shall be solid.
• Front and back enclosed by solid material or by wire mesh or perforated metal.
• Guard for the portion of the blade between the sliding guide and the upper-saw-wheel guard shall protect the saw blade at the front and outer side.
• Self-adjusting to raise and lower with the guide.
Slide 102 (of 185)
Band Saw
Slide 103 (of 185)
Band Saw
Slide 104 (of 185)
Slide 105 (of 185)
10.213(j)(3) Hand-Fed Jointer • Automatic guard which will cover all the section of the head on the
working side of the fence or gage.
• Effectively keep the operator's hand from coming in contact with the revolving knives.
• Automatically adjust itself to cover the unused portion of the head and shall remain in contact with the material at all times.
Slide 106 (of 185)
• Cutting heads of each wood shaper, hand-fed panel raiser, or other similar machine not automatically fed, shall be enclosed with a cage or adjustable guard so designed as to keep the operator's hands away from the cutting edge.
1910.213(m)(1) Wood Shapers and Similar Equipment
Slide 107 (of 185)
10.213(o)(2) Cutting Heads on Wood- Turning Lathes• Covered as completely as possible by hoods or shields.
Slide 108 (of 185)
• Feed rolls of self-feed sanding machines must be protected with a semi cylindrical guard to prevent the hands of the operator from coming in contact with the in-running rolls at any point.
• Guard must be constructed of heavy material, preferably metal, and firmly secured to the frame carrying the rolls so as to remain in adjustment for any thickness of stock.
• The bottom of the guard should come down to within three-eighths inch of a plane formed by the bottom or contact face of the feed roll where it touches the stock.
1910.213(p)(1) Sanding Machines
Slide 109 (of 185)
Circular Sander
Slide 110 (of 185)
Unguarded belt sander
Slide 111 (of 185)
Slide 112 (of 185)
Saw Blade
1910.213(s)(7)&(8)
Slide 113 (of 185)
Table Saw
Slide 114 (of 185)
Swing Cut off Saw
Slide 115 (of 185)
Table Saw
Slide 116 (of 185)
Table Saw
Slide 117 (of 185)
Belt Sander
Slide 118 (of 185)
Table Saw
Slide 119 (of 185)
Table Saw
Slide 120 (of 185)
Power Molding Machine
Slide 121 (of 185)
Table Saw
Slide 122 (of 185)
Table Saw
Slide 123 (of 185)
Dado Blade on Radial Saw
Slide 124 (of 185)
Power Fed Rip Saw
Slide 125 (of 185)
Radial Arm Saw
Slide 126 (of 185)
Radial Arm Saw
Slide 127 (of 185)
1910.215 AbrasiveWheel Machinery
Slide 128 (of 185)
Slide 129 (of 185)
Slide 130 (of 185)
Slide 131 (of 185)
• The safety guard shall cover the spindle end, nut, and flange projections.
1910.215(a)(2) Guard Design
Slide 132 (of 185)
Safety Guard
Slide 133 (of 185)
• On offhand grinding machines, work rests shall be used to support the work. They shall be of rigid construction and designed to be adjustable to compensate for wheel wear. Work rests shall be kept 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. The work rest shall be securely clamped after each adjustment. The adjustment shall not be made with the wheel in motion.
1910.215(a)(4) Work Rests
Work rest 1/8”
Slide 134 (of 185)
Exposure adjustment
one-fourth inch
1910.215(b)(9) Tongue Guard
Slide 135 (of 185)
• (1) Inspection. – 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
1910.215(d) Mounting - Wheel Speed
Slide 136 (of 185)
• (1) Inspection– Wheels should be tapped
gently with a light nonmetallic implement, such as the handle of a screwdriver for light wheels, or a wooden mallet for heavier wheels. If they sound cracked (dead), they shall not be used. This is known as the "Ring Test".
1910.215(d) Mounting - Ring Test
“Ring test”
Slide 137 (of 185)
• Self Closing Guard– Effective two years after approval of this
revision for existing machines, all floor stand grinders for use with a 24” diameter wheels or larger where personnel are required to be in the plane of rotation of the wheel shall be equipped with guards which close automatically in case of wheel breakage. Other guard designs which provide equivalent protection to the personnel in the plane of rotation of the wheel may be used.
FLOOR STAND GRINDERSANSI B.7.1-1988 E 4.3.2
Slide 138 (of 185)
Slide 139 (of 185)
Guard Down
Slide 140 (of 185)
Slide 141 (of 185)
Surface grinder with top guard
Slide 142 (of 185)
29CFR 1910.219 Mechanical Power-Transmission
Apparatus
Slide 143 (of 185)
• (1) This section covers all types and shapes of power-transmission belts, except the following when operating at two hundred and fifty (250) feet per minute or less:– (i) Flat belts one (1) inch or less in
width,– (ii) Flat belts two (2) inches or less
in width which are free from metal lacings or fasteners,
– (iii) Round belts one-half (1/2) inch or less in diameter; and
– (iv) Single strand V-belts, the width of which is thirteen thirty-seconds (13/32) inch or less.
1910.219(a) General Requirements
Slide 144 (of 185)
• (2) Vertical and inclined belts (paragraphs (e) (3) and (4) of this section) if not more than two and one-half (2 1/2) inches wide and running at a speed of less than one thousand (1,000) feet per minute, and if free from metal lacings or fastenings may be guarded with a nip-point belt and pulley guard.
1910.219(a) General Requirements
Slide 145 (of 185)
Belt speed exceeds one thousand (1,000) feet per minute
Slide 146 (of 185)
• (1) Flywheels located so that any part is seven (7) feet or less above floor or platform shall be guarded in accordance with the requirements of this subparagraph:
1910.219(b) Flywheels
(7) feet or less above floor or platform shall be guarded
Slide 147 (of 185)
This is in further response to your letter dated April 5, 1983, concerning the guarding of flywheels on power presses.
The Occupational Safety and Health Administration's General Industry Standards 29 CFR 1910.219(b)(1) and (b)(1)(vi) require guarding of the press flywheel. Furthermore, the latter provision requires that flywheels above working areas be provided with guards of sufficient strength to contain the flywheel in the event of shaft or wheel mounting failure.
Reference to ANSI 815.1-1972, the current version of the source standard, rapidly demonstrates that structural failures are possible. Appendix AB.1 of ANSI 815.1 indicates that failures of a fatigue nature can be anticipated, particularly for older machines that have been continually exposed to cyclic leads.
Therefore, substantial guarding is necessary to provide safety. That company die setter's need to have easy access to the flywheel for die-setting for is completely valid and should be a major consideration of the guarding provided. In that regard, the guard configuration enclosed is recommended for consideration.
LETTER OF INTERPRETATION
Slide 148 (of 185)
1910.219(c) Shafting
Rotating pulley
Rotating shaft
Rotating coupling
Burr
Slide 149 (of 185)
• (i) All exposed parts of horizontal shafting seven (7) feet or less from floor or working platform, excepting runways used exclusively for oiling, or running adjustments, shall be protected by a stationary casing enclosing shafting completely or by a trough enclosing sides and top or sides and bottom of shafting as location requires.
1910.219(c)(2) Guarding Horizontal Shafting
Shafting must be guarded
Slide 150 (of 185)
• (i) Projecting shaft ends shall present a smooth edge and end and shall not project more than one-half the diameter of the shaft unless guarded by nonrotating caps or safety sleeves.
• (ii) Unused keyways shall be filled up or covered.
1910.219(c)(4) Projecting Shaft Ends
Shafting shall not extend morethan 1/2 the diameter of theshaft unless guarded
Slide 151 (of 185)
• (1) Pulleys, any parts of which are seven (7) feet or less from the floor or working platform, shall be guarded in accordance with the standards specified in paragraphs (m) and (o) of this section.
1910.219(d) Pulley Guarding
Slide 152 (of 185)
Slide 153 (of 185)
1910.219(f) Gears, Sprockets,and Chains
Slide 154 (of 185)
• (1) Gears shall be guarded in accordance with one of the following methods:– (i) By a complete enclosure; or– (ii) By a standard guard as described
in paragraph (o) of this section, at least seven (7) feet high extending six (6) inches above the mesh point of the gears; or
– (iii) By a band guard covering the face of gear and having flanges extended inward beyond the root of the teeth on the exposed side or sides. Where any portion of the train of gears guarded by a band guard is less than six (6) feet from the floor a disk guard or a complete enclosure to the height of six (6) feet shall be required.
1910.219(f) Gears
Slide 155 (of 185)
• All sprocket wheels and chains shall be enclosed unless they are more than seven (7) feet above the floor or platform. Where the drive extends over other machine or working areas, protection against falling shall be provided.
1910.219 (f)(3) Sprockets and Chains
Slide 156 (of 185)
• (1) Collars. All revolving collars, including split collars, shall be cylindrical, and screws or bolts used in collars shall not project beyond the largest periphery of the collar.
• (2) Couplings Shaft couplings shall be so constructed as to present no hazard from bolts, nuts, setscrews, or revolving surfaces. Bolts, nuts, and setscrews will, however, be permitted where they are covered with safety sleeves or where they are used parallel with the shafting and are countersunk or else do not extend beyond the flange of the coupling.
1910.219 (i) Collars and Couplings
Slide 157 (of 185)
• (1) Materials– (i) Standard conditions shall be guarded by the use of the
following materials. Expanded metal, perforated or solid sheet metal, wire mesh on a frame of angle iron, or iron pipe securely fastened to floor or to frame of machine.
– (ii) All metal should be free from burrs and sharp edges.
1910.219(m) Standard GuardsGeneral Requirements
Slide 158 (of 185)
• (1) Minimum requirements. – The materials and
dimensions specified in this paragraph shall apply to all guards, except horizontal overhead belts, rope, cable, or chain guards more than seven (7) feet above floor, or platform.
1910.219(o) Approved Materials
Slide 159 (of 185)
• (i) Wood guards may be used in the woodworking and chemical industries, in industries where the presence of fumes or where manufacturing conditions would cause the rapid deterioration of metal guards; also in construction work and in locations outdoors where extreme cold or extreme heat make metal guards and railings undesirable. In all other industries, wood guards shall not be used.
1910.219(o)(2) Wood Guards
Wood guard
Wood guard
Slide 160 (of 185)
29 CFR 1910.261Paper, Pulp & Paperboard Mills
Application of 29 CFR 1910.212
Slide 161 (of 185)
Hydro Pulper
Slide 162 (of 185)
Fourdrinier
Slide 163 (of 185)
Screen Roll
Slide 164 (of 185)
Screen Cleaning
Slide 165 (of 185)
Threading the Presses (Tailing)
Slide 166 (of 185)
Cooch Carrier Roll Nip Point
Slide 167 (of 185)
Cooch Carrier Roll Nip Point
Slide 168 (of 185)
First Press Nip Point
Slide 169 (of 185)
Press Section / First Dryer
Slide 170 (of 185)
Cylinder Machine Nip Point
Slide 171 (of 185)
Cleaning the Press Roll
Slide 172 (of 185)
Dryers (Front Side)
Slide 173 (of 185)
Dryer (Back Side)
Slide 174 (of 185)
Slide 175 (of 185)
Isolation Guarding
Slide 176 (of 185)
Line Shaft
Slide 177 (of 185)
Incline Belts and Pulleys
Slide 178 (of 185)
Tailing (Threading) the Dryer
Slide 179 (of 185)
Dryer Nip Point
Slide 180 (of 185)
Reel Nip Point
Slide 181 (of 185)
Rewinder Nip Point
Slide 182 (of 185)
Guarded Rewinder
Slide 183 (of 185)
Rotary Cutters
Slide 184 (of 185)
Embosser Nip Point
Slide 185 (of 185)
Nip Point Guarding