Transcript Machine Guarding - Ringling College of Art and Design

MACHINE
GUARDING
Ringling College of Art & Design
Department of Environmental Health and Safety
INTRODUCTION



This online training course provides general
information on machine guarding. All machine
operators must complete this training and the
quiz.
Specific information on machine hazards are
provided by each department.
The course introduces the different methods of
machine guarding, hazardous motions and
actions, requirements for guards, and examples
of guarding.
INTRODUCTION
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Machine guarding prevents body parts and
objects from coming into contact with dangerous
parts of machinery.
Crushed hands and arms, severed fingers,
blindness - the list of possible machinery-related
injuries is as long as it is horrifying. Safeguards
are essential for protecting workers from
needless and preventable injuries and deaths.
A good rule to remember is: Any machine part,
function, or process which may cause injury must
be safeguarded.
INTRODUCTION
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
Machine guards differ for every machine due to
the varying physical characteristics of
machinery.
Machine guarding is required by OSHA (29 CFR
1910.212) for any machine that has the potential
of causing an injury.
GENERAL REQUIREMENTS
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1.
Machines have four main general requirements:
Electrical power and controls

Each machine must be equipped with a master switch that
can be locked and/or tagged during repair or maintenance
operations.

Power controls and operating controls must be located
within easy reach of the operator.
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A trip device must be provided on machinery where injury
might result if motors were to restart after power failures.
This prevents the machine from operating when electric
service is restored.

Main "kill" switches should be centrally installed, easily
identified and accessible to operators or shop supervisors /
co-workers for use in interrupting power in emergency
situations.
GENERAL REQUIREMENTS
2.
Guarding

Appropriate guards must be provided to protect the
operator and others in the area from hazards.

No employee or student shall operate and/or cause to
be operated, any machinery without proper protective
devices in place.

Combs (feather boards) or suitable jigs must be
provided for use when a standard guard cannot be
used.

The operator should never perform layout, assembly
or set-up work on the table/work area when the
machine is running.
GENERAL REQUIREMENTS
3.
Personal Protective Equipment

Personal protective equipment may still be required;
closed toed shoes, eye and hearing protection are
frequently necessary.

Heavy aprons are encouraged when operating
machinery that may produce kickbacks of stock.

Loose fitting clothing must not be worn.
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Gloves, rings, neck chains and other jewelry must not
be worn on moving machinery.
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Long hair must be restrained.
GENERAL REQUIREMENTS
4.
Housekeeping
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Metal slivers, sawdust and other debris should be cleaned
from the machine using a brush or rag. Never use bare
hands for the task. NEVER clean a machine while it is in
motion.
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If available, the dust collection system should be used at all
times. Do not combine wood dust and metal filings.
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To reduce the airborne dust levels, compressed air may be
used for minor cleaning purposes only after the majority of
the dust has been cleaned up manually and where the
pressure is reduced to less than 30 P.S.I. (pounds per
square inch) Eye protection must be worn while using
compressed air to clean equipment.
GENERAL REQUIREMENTS
4.
Housekeeping
(cont.)

Oily rags, waste, and other materials saturated with
combustible substances must be disposed of in
approved metal containers equipped with self-closing
lids.

Local exhausts should be installed on machines
where large amounts of dust are produced, such as
sanders and planers.

Safety zones surrounding machines should be
established and marked. Machines should be spaced
to allow for the establishment of safety zones.
CAUSES OF MACHINE
ACCIDENTS
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Familiarity with machine – operator believes
that they are skilled enough to use machine
without the guard.
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Reaching in to “clear” equipment.
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Unauthorized person using machine.
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Not using lock-out / tag-out – during
maintenance.
Lack of concentration.
COMPONENTS OF MACHINES
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A machine consists of three basic mechanical
components:
Point of operation
 Power transmission device
 Other moving parts
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
NOTE: Even though machines have three basic
components, the guarding requirements will
differ on machinery.
COMPONENTS OF MACHINES
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Point of Operation

Where the work is performed on
the material (i.e. cut / shear).
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Must be guarded.
Point of
Operation
COMPONENTS OF MACHINES
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Power transmission device
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This is the mechanical component
that transmits energy to the part
of the machine that performs the
work (i.e. belt / pulley / flywheel).
Power
Transmission
Device
COMPONENTS OF MACHINES
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Other moving parts

Other
Other moving parts (spindle andMoving
Parts
chuck on a drill press) of the
machine that move while the
machine is operating.
HAZARDOUS MOTIONS &
ACTIONS
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Machine guards must protect from hazardous
motions and hazardous actions.
Hazardous motions include:
Rotating motion
 Reciprocating motion
 Transverse motion
 In-running nip points (pinch points)
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HAZARDOUS MOTIONS &
ACTIONS
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Rotating motion - circular motion

Rotating parts can “grab” clothing, hair or a body
part and force it into a dangerous area.
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Examples include flywheels, rotating shaft end and
meshing gears.
HAZARDOUS MOTIONS &
ACTIONS
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Reciprocating motion
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A back and forth motion or up and down motion that
can strike or pin someone between a moving part and
a fixed object.
Forming
machine
HAZARDOUS MOTIONS &
ACTIONS
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Transverse motion

A movement in a straight and continuous line.
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Examples include conveyor belt and belt sander.
HAZARDOUS MOTIONS &
ACTIONS
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In-running nip points – 3
types
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Rotating
cylinder
Parts can rotate in opposite
directions, while their axes are
parallel to each other.
A rotating part and a
tangentially moving part.
Rotating part and fixed part
which can create a shearing,
crushing or abrading action.
Chain and
sprocket
Abrasive
wheel & work
rest
HAZARDOUS MOTIONS &
ACTIONS
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Hazardous actions include:
Cutting action
 Punching action
 Shearing action
 Bending action
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HAZARDOUS MOTIONS &
ACTIONS
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Cutting action – hazards exist at the point of
operation and also from flying chips or ejected
materials.
Drill press
Router
HAZARDOUS MOTIONS &
ACTIONS
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Punching action – power is applied to a slide
(ram) for the purpose of blanking, drawing or
stamping materials.
Power press
HAZARDOUS MOTIONS &
ACTIONS
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Shearing action – power is applied to a slide or
knife used to trim or shear materials.
Guard
Metal shear
with guard
Shear
Shearing action
HAZARDOUS MOTIONS &
ACTIONS
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Bending action – power is applied to a slide to
draw, turn or stamp materials.
Tube bender
Bend sheet
metal
SAFEGUARDING REQUIREMENTS
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Machine guards must meet or exceed the
following 6 OSHA requirements:
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Prevent contact
Be secure
Protect from falling objects
Does NOT create a new hazard
Does NOT create an interference
Allows for safe lubrication
SAFEGUARDING REQUIREMENTS
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Prevent contact
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Prevent workers body or clothing from contacting the
hazardous moving parts.
Be secure
Firmly secured to the machine.
 Not easily removed from machine.
 Made of durable material that will withstand the
conditions of normal use.
 A safeguard that can easily be made ineffective is no
safeguard at all.
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SAFEGUARDING REQUIREMENTS
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Protect from falling objects
Ensure that no objects can fall into moving parts.
 A small tool dropped into a machine could become a
projectile causing an injury.
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Does NOT create a new hazard
Must not have shear points, jagged edges or
unfinished surfaces.
 Edges of guards must not have sharp edges.
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SAFEGUARDING REQUIREMENTS
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Does NOT create an interference
Must not prevent worker from performing the job
quickly and comfortably. A safeguard that impedes a
workers performance may be overridden or
disregarded.
 Proper safeguarding can enhance efficiency, since it
relieves apprehension about injury.
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Allows for safe lubrication
If possible, be able to lubricate the machine without
removing the safeguards.
 Locating oil reservoirs outside the guards with lines
leading to the lubrication point will reduce
requirement to enter hazardous area.
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METHODS OF SAFEGUARDING
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Machine guarding decisions should be made in
the following order (hierarchy):
1.
2.
3.
4.
5.
6.
Design out or eliminate the hazard
Physically “engineer out” the exposure to the
hazard
Guard the hazard — personal protective equipment
may also be required
Use warning devices, or make the danger clearing
apparent
Use warning signs
Use safe working practices and procedures
METHODS OF SAFEGUARDING
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We will review the following types of
safeguarding:
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Guards
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Devices
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Location / Distance
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Feeding and ejection methods
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Miscellaneous aids
SAFEGUARDING - GUARDS
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There are four main types of guards:
1 Fixed guard
• Provides a barrier
•
•
A permanent part of the machine
Preferable to all other types of guards;
best protection for guarding.
SAFEGUARDING - GUARDS
2 Interlocked guard
• When the guard is opened or 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.
Interlocking
guard on
revolving drum
SAFEGUARDING - GUARDS
3 Adjustable guard
• Provides a barrier which may be adjusted to
facilitate a variety of production operations.
• Subject to human error.
Bandsaw blade
adjustable guard
SAFEGUARDING - GUARDS
4 Self adjusting guard
• Provides a barrier which moves according to the
size of the stock entering the danger area.
• Avoids the potential for human error.
Self adjusting
guard on table saw
SAFEGUARDING - DEVICES
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Devices prevent the operator from making
contact with the point of operation.

This can be achieved with a pullback or restraint
device that allows the operator’s hands to travel
within a predetermined safe area.
SAFEGUARDING - DEVICES
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Other devices include tripwire cables located
around the perimeter of or near the danger area.
A two-hand control requires constant concurrent
pressure to activate the machine.
SAFEGUARDING - LOCATION
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Locate the machine or its dangerous moving
parts so that they are not accessible or do not
present a hazard to a operator.
Maintain a safe distance from the danger area.
SAFEGUARDING – FEEDING
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Feeding and ejection methods include automatic
and / or semi-automatic feed and ejection
techniques. Material is fed into the machine
eliminating the need for the operators
involvement.
Other guards are
required for operators
protection.
Stock
feed roll
Transparent
enclosure
guard
SAFEGUARDING – MISC. AIDS
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3 miscellaneous aids will be discussed:
1 Protective shields
These do NOT give complete protection from
machine hazards, but do provide some protection
from flying particles, splashing cutting oils or
coolants.
SAFEGUARDING – MISC. AIDS
2 Hand feeding tools
• For placing and removing materials to prevent
the operator placing a hand in the danger zone.
• These must be used in conjunction with other
required machine guard/s. Example, a push stick
used in conjunction with a self adjusting guard
on a table saw.
Push block
Fingerboard
Push stick
SAFEGUARDING – MISC. AIDS
3 Awareness barriers
• Serves as a reminder to a person that they are
approaching the danger area. The barrier does
NOT prevent the person from entering the
danger area, but calls their attention to it.
•
Should NEVER be the only method of “guarding”
an area as it is not considered an adequate
means of prevention. Example, a high visibility
tape.
CONSTRUCTION - MACHINE
GUARDING
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Most machine guards are provided with the
equipment or can be purchased from the
manufacturer.
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Advantages: The guard conforms to the design and
function of the machine and it can strengthen the
machine through its design or serve an additional
function.
Chop saw
Paper cutter
CONSTRUCTION - MACHINE
GUARDING
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When a guard cannot be purchased from the
manufacturer, one may be user built providing:
It is fabricated to function effectively and
 It meets the specifications for guarding of the specific
machine.
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NOTE Just because a guard is not specifically made
for a machine, this does NOT mean that a guard does
not have to be in place. Machine guarding is required
on ALL machinery where a risk of an injury exists.
Before
and
After
MACHINE MAINTENANCE &
REPAIR
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During servicing or maintenance the following 6
steps must be followed:
1.
Notify all affected employees (usually machine
or equipment operators or users) that the
machine or equipment must be shut down to
perform some maintenance or servicing;
2.
Stop the machine;
3.
Isolate the machine or piece of equipment from
its energy source;
MACHINE MAINTENANCE &
REPAIR
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During servicing or maintenance the following 6
steps must be followed: (cont.)
4.
Lock out and / or tag out the energy source;
5.
Relieve any stored or residual energy; and
6.
Verify that the machine or equipment is
isolated from the energy source.
MACHINE MAINTENANCE &
REPAIR
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Although the 6 steps are a general rule, there are
exceptions when the servicing or maintenance is:

not hazardous for an employee,
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when the servicing which is conducted is minor in
nature,
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done as an integral part of production, and the
employer utilizes alternative safeguards which
provide effective protection as is required by 29 CFR
1910.212 or other specific standards.
MACHINE MAINTENANCE &
REPAIR

When the servicing or maintenance is completed,
there are specific steps which must be taken to
return the machine or piece of equipment to
service. These steps include:
1.
Inspection of the machine or equipment to
ensure that all guards and other safety devices
are in place and functional,
2.
Checking the area to ensure that energization
and start up of the machine or equipment will
not endanger employees,
MACHINE MAINTENANCE &
REPAIR

When the servicing or maintenance is completed,
there are specific steps which must be taken to
return the machine or piece of equipment to
service. These steps include: (cont.)
3.
Removal of the lockout devices,
4.
Reenergization of the machine or equipment,
and
5.
Notification of affected employees that the
machine or equipment may be returned to
service.
MACHINE MAINTENANCE &
REPAIR


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If it is necessary to oil machine parts while the
machine is running, special safeguarding
equipment may be needed solely to protect the
oiler from exposure to hazardous moving parts.
Maintenance personnel must know which
machines can be serviced while running and
which can not.
The danger of accident or injury is greatly
reduced by shutting off and locking out all
sources of energy.
LOCK OUT / TAG OUT
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
Lock out / Tag out (control of
hazardous energy) is an integral
part of workplace safety. When
machine guarding must be removed
for maintenance, specific procedures
must be followed.
Lock out / Tag out is a separate
training program. If training is
required contact the EHS
department.

NOTE: See the Colleges Lock out / Tag
out procedure and training
information on the EHS website.
RESPONSIBILITIES

Departments – supervisors

Ensure all machinery is properly guarded

Train employees on specific guard rules in their areas

Ensure machine guards remain in place and are
functional
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Immediately correct machine guard deficiencies
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Annually complete the inspection form – see the
College’s machine guarding program
RESPONSIBILITIES

Employees

Complete generic EHS training

Do not remove guards unless machine is locked and
tagged

Report machine guard problems to supervisors
immediately

Do not operate equipment unless guards are in place
EXAMPLES - MACHINE
GUARDING

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 1/2 inch.
7 foot
EXAMPLES - MACHINE
GUARDING

Abrasive wheel machinery – Work rests on
offhand grinding machines must be kept adjusted
closely to the wheel with a maximum opening of
1/8th inch to prevent the work from being jammed
between the wheel and the rest, which may
result in wheel breakage.
EXAMPLES - MACHINE
GUARDING

Abrasive wheel machinery – The distance
between the wheel periphery and the adjustable
tongue must never exceed ¼ inch.
EXAMPLES - MACHINE
GUARDING
EXAMPLES - MACHINE
GUARDING
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Belt and pulley – Power transmission apparatus
less than 7 feet from the floor or working
platform must be guarded.
Guard
required
SUMMARY - MACHINE
GUARDING
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Machine guarding is important for your personal
health and safety and those that work around
you.
Before beginning daily work activities, assess all
work areas where machinery is present and
check for possible hazards/missing guards/etc.
Make sure that all guards on equipment are
adjusted and functioning properly. Guarding
should never be removed except for maintenance
procedures.
If machine guarding is not in place do not use the
equipment, and use proper procedures to ensure
that guarding is put in place.
SUMMARY - MACHINE
GUARDING
If you have any questions or concerns
about machine guarding
contact your supervisor
or the EHS department.
Now please
complete the quiz