in Figure 17, a transparent. fixed barrier guard is being used on a press
brake to protect the operator from the unused portions of the die. This guard

is easy to install or remove.

interlocked: When this type of guard is opened or removed, the tripping
mechanism and/or power automaticaly shuts off or disengages, and the
machine cannot cycle or be started until the guard is back in place.

pneumatic power or any combination of these.
“inching” by remote contro! if required. Replacing the guard should not
automaticaily restart the machine. To be effective. all movable guards
should be interlocked to prevent occupational hazards.

(See alse Figure 13.}

16

Figure 17.

Fixed guard providing
protection from unused portion
of die on a press brake


as Le
ove EE

owe

}

Figure 43.
Safety tripwire cable on
a calender

tomato sorter

DISCHARGE
BELT

DISPOSAL, ie
CHUTE

37


Figure 39.
igu

Restraint device on power press

\
)
/

On

NY

|
N
DX

|]
Mm

\
Ns ~
2

°
la

f
4)
\

!
i

(|

[EN fo |
aE |
) J ) al

Cc

i
=

Restraint

2 Sr
must be adjusted to let the operator's hands travel within a predetermined
safe area. There is no extending or retracting action involved. Consequently,
hand-feeding tools are often necessary if the operation involves placing

material into the danger area.

33


Figure 47.
Horizontal injection molding
machine with gate

Gate

A gate is a moveable barrier that protects the operator at the point of
operation before the machine cycle can be started. Gates are, in many
instances, designed to be operated with each machine cycle.

Figure 47 shows a horizontal injection moiding machine with a gate. To be
effective, the gate must be interlocked so that the machine will not begin a
cycle unless the gate guard is in place. !t must be in the closed position
before the machine can function.

Figure 48 shows a gate on a power press. If the gate is not permitted to
descend to the fully closed position, the press will not function.

Another potential application of this type of guard 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.

Safeguarding by Location/Distance

The exampies mentioned below are a few of the numerous applications of
the principie of safeguarding by iocation/distance. A thorough hazard
analysis of each machine and particular situation is absolutely essential
before attempting this safeguarding technique.

To consider a part of a machine to be safeguarded by location, the

dangerous moving part of a machine must be so positioned that those areas
are not accessible or do not present a hazard to a worker during the normal

42


Protective Clothing and Personal
Protective Equipment

Engineering controls, that eliminate the hazard at the source and do not rely
on the worker's behavior for their effectiveness offer the best and most
reliable means of safeguarding. Therefore, engineering controls must be the
employer's first choice for eliminating machine hazards. But whenever
engineering controls are not available or are not fully capable of protecting
the employee (an extra measure of protection is necessary), operators must
wear protective clothing or personal protective equipment.

If it is to provide adequate protection, the protective clothing and equipment
selected must aiways be:

(1) appropriate for the particular hazards;
(2) maintained in good condition;
(3) properly stored when not in use, to prevent damage or loss; and

(4) kept clean, fully functional. and sanitary.

Protective clothing is. of course. available for different parts of the body.
Hard hats can protect the head from the impact of bumps and falling objects
when the worker is handling stock; caps and hair nets can help keep the
worker's hair from being caught in machinery. If machine coolants could
splash or particies could fly into the operator's eyes or face, then face
shields, safety goggles, glasses, or similar kinds of protection might be
necessary. Hearing protection may be needed when workers operate noisy
machines. To guard the trunk of the body from cuts or impacts from heavy or
rough-edged stock, there are certain protective coveralls, jackets, vests,
aprons, and full-body suits. Workers can protect their hands and arms from
the same kinds of injury with special sleeves and gloves. Safety shoes and
boots, or other acceptable foot guards, can shield the feet against injury in
case the worker needs to handle heavy stock which might drop.

Itis important to note that protective clothing and equipment can create
hazards. A protective glove which can become caught between rotating
parts, or a respirator facepiece which hinders the wearer's vision, for
example, require alertness and continued attentiveness whenever they
are used.

Other parts of the worker's clothing may present additional safety hazards.
For example, loose-fitting shirts might possibly become entangled in rotating
spindles or other kinds of moving machinery. Jewelry, such as bracelets and
rings, can catch on machine parts or stock and lead to serious injury by
pulling a hand into the danger area.

10


Chapter 7

A recent development in manufacturing technology has given rise toa
manufacturing concept known as Manufacturing Systems/Cells, or Cellular
Manufacturing Systems. These systems of integrated industrial machines,
linked by a material handling system and operated by (controlled by) a
programmable electronic system (computer) are capabie of manufacturing

feorate oars 3 safety of employees exposed to these

discrete parts or assemblies. The safety of employees exposed to these

systems is of first order importance.

Because a system is to be safeguarded it is logical that a system hazard
analysis will yield the parameters of the safeguarding system required.
Figures 73 through 75 depict typical cellular system concepts and
safeguarding considerations.

>

NS! 811.20-1991, should be referred to for assistance when a cellular

}
manufacturing system is envisioned.


Figure 62.
Potential danger areas in
robot envelope

Figure 63.
Using barrier guards to protect
robot envelope

52


COMPLETED
PART

|

SST ain Nozze

CHUTE : —, r

Figure 58.
Air ejection

Figures 58 and 59 show air ejection and mechanical ejection mechanisms,
respectively. Note: Air ejection methods often present a noise hazard

to operators.

Figure 60 shows a semiautomatic ejection mechanism used on a power
press. When the plunger is withdrawn from the die area, the ejector leg,
which is mechanically coupled to the plunger, kicks the completed work out.

Essentially, robots perform work that would otherwise have to be done by

an operator. They are best used in high-production processes requiring
repeated routines where they prevent other hazards to employees. However,
they may create hazards themselves, and it they do, appropriate guards
must be used.

Figures 61, 62, and 63, respectively, show a type of robot in operation, the
danger areas it can create. and an example of the kind of task (feeding a
press) it can perform.

Figure 59.
Mechanical ejection

MECHANICAL >
EJECTOR i

COMPLETED t
PART >

CHUTE a

50


we LE

e ‘PLIERS WITH CURVED HANDLES
OUCKBILL PLIERS FOR TWO-HANDED USAGE
<A
Cc OA ANGLE JAW TONGS:
FOR HANDLING FLANGED OR

K.. A p) CUPSHAPEO WORK PIECES

A LIGHTWEIGHT TWEEZER
MADE OF STEEL SPRING

A
a

—_—
> —— MAGNETIC LIFTER —

TWiST-OFF

> DS ——»)
LA Re _ LE

on
to)

Figure 67.

Holding tools


Good maintenance and repair procedures contribute significantly to the
safety of the maintenance crew as weii as that of machine operaiors. The
variety and complexity ot machines to be serviced. the hazards associated

their

th
with their

ower sources, the spec

machine breakdown, and the severe time constraints often 9
rey

maintenance personnel all make safe maintenance and

2
fe
x
a
x
3
=

Training and aptitude of people assigned to these jobs should make them
aiert for the intermittent eiectricai faiiure, the worn part, the inappropriate

operators at t their tasks and listening to their comments, maintenance
personnel may learn where potential trouble spots are and give them early
attention before they develop into sources of accidents and injury.
Sometimes ail that is needed to keep things running smoothly and safely is
machine lubrication or adjustment. Any damage observed or suspected
should be reported to the superviso! if the condition impairs safe operation,

g, altered, or damaged also should be reported so a

ng. altered, or damaged also should be reported so aj

can be taken to insure against worker injury.

a
a
3

If possible, machine design should permit routine lubrication and adjustment
without removal of safeguards. But when safeguards must be removed, and
the machine serviced, the iockout procedure of 29 CFR 1910.147 must be
adhered to. The maintenance and repair crew must never fail to replace the
guards before the job is considered finished and the machine released

from lockout.

Is it necessary to oil machine parts while a machine is running? If so. special
safeguarding equipment may be needed solely to protect the oiler from
exposure to ‘hazardous moving parts. Maintenance personnel must know

nergy.

In situations where the maintenance or repair worker would necessarily be
exposed to electrical elements or hazardous moving machine parts in the
performance of the job, there is no question that ail power sources must be
shut off and iocked out before work begins. Warning signs or tags are
inadequate insurance against the untimely energizing of

mechanica! equinment.
mechanical! equipment.

Thus, one of the first procedures for the maintenance person is to
disconnect and lock out the machine from ail of its power sources, whether

the source is electrical, mechanical, pneumatic. hydraulic, or a combination
of these. Energy accumuiation devices must be “bied down.”

Electrical: Unexpected energizing of any electrical equipment that can be
started by automatic or manual remote control may cause electric shock or

61


_—— —
a TM
Lo BOLSTER IN RETRACTED: oN

DIE IN STOCK PLACEMENT
OR REMOVAL POSITION

Te « posit .
(BOLSTER Its EXTENDED POSITION: Figure 55.

Power press with sliding bolster

Figure 56 shows a double-dial feed. The dials revolve with each stroke of
the press. The operator places the part to be processed in a nest on the dial
i f indexed with each upstroke
9 the die.

of the cress to di

of the press to deliver the nested part |

Automatic ejection may employ either an air-pressure or a mechanical
apparatus to remove the completed part from a press. It may be interlocked
with the operating controls to prevent operation until part ejection is
completed. This method requires additionai safeguards for fuli protection of
the operator.

48


Adjustable guard on

Power press

iN
@
g
8
we

3
=]
i)
; @
SE:
S32
ges
Bo c
ues

BASE OF
ROUTER BLADE

20


CONTROL

BUTTONS

NEw

All of these tripwire rods or other safety devices must be manually reset to
restart the machine. Simply releasing the tnpwire to restart the machine will
not ensure that the empioyee is out of danger when the machine restarts.

The two-hand control requires constant. concurrent Pressure by the operator
to activate the machine. This kind of control requires a p: clutch,
brake, and a brake monitor if used on a power press as shown in igure 45.
With this type of device. the operator's hands are required to be ata safe
location (on contro! buttons) and at a safe distance from the danger area

while the machine completes its closing cycle.

38

Figure 45.

Two-hand controi buttons
Of part-revoiution clutch
power press


Human errors can result in hazards both to personnel and equipment. Errors
in programming, interfacing peripheral equipment, connecting input /output
sensors, can all result in unpredicted movement or action by the robot which
can result in personnel injury or equipment breakage.

Human errors in judgment result frequently from incorrectly activating the
teach pendant or control panel. The greatest human judgment error results
from becoming so familiar with the robot's redundant motions that personnel
are too trusting in assuming the nature of these motions and place
themselves in hazardous positions while programming or performing
maintenance within the robot's work envelope.

Robots in the workplace are generally associated with machine tools or
process equipment. Robots are machines, and as such must be
safeguarded in ways similar to those presented for any hazardous remotely
controlled machine.

Various techniques are available to prevent employee exposure to the
hazards which can be imposed by robots. The mast common technique is
through the installation of perimeter guarding with interlocked gates. A
critical parameter relates to the manner in which the interlocks function. Of
major concern is whether the computer program, control circuit, or the
primary power circuit, is interrupted when an interlock is activated. The
various industry standards should be investigated for guidance; however, it
is generally accepted that the primary motive power to the robot should be
interrupted by the interlock.

The ANSI safety standard for industrial robots, ANSI/RIA R15.06-1986, is
very informative and presents certain basic requirements for protecting the
worker. However, when a robot is to be used in a workplace, the employer
should accomplish a comprehensive operational! safety/health hazard
analysis and then devise and implement an effective safeguarding system
which is fully responsive to the situation. (Various effective safeguarding
techniques are described in ANSI B11.19-1990.)

72


pa:
machines. Safeguards a are essential for protecting workers from needless
and preventabie injuries.

may cause injury must be safeguarded, When’ th

accidental contact
accidental contact

hazards must be either controlled or eliminated.

it can i

it can injure the ope:

This manual describes the various hazards of mechanical motion and
presents some techniques for protecting workers from these hazards.
General information covered iS chapter includes — where mechanical
hazards occur, the hazards created by different kinds of motions and the

tequirements for effective safeguards, as well as a brief discussion of

nonmechanica! hazards.

Where Mechanical Hazards Occur

Dangerous moving parts in three basic areas require safeguarding:

The 2 point of operation: that point where work is performed on the material,

ag. o¢ forming of stock

ig, 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, spindies, chains, cranks, and gears.

Oiher moving part: parts of the machine which move while the maci
is working. These can include recipracating, rotating, and transverse moving
as feed mechanisms and auxiliary parts of the machine.

Hazardous Mechanical Motions and Actions

A wide variety of mechanicai motions and actions may present hazards to
the worker. These can include the movement of rotating members,
reciprocating arms, moving belts, meshing gears, cutting teeth, and any
parts that impact or shear. These different types of hazardous mechanical
sic in varying co: ions to nearly all

varying cor

motions and actions are

machines, and recognizing them is the first step toward protecting workers
from the danger they present.



Load/Unicad Station. ~<DFGe
sncny cota Ca ES
=p

Inspection Modules.

with Wire-Guided Path. Manuai inspeciion Siation.
CNCM Controt Center

Computer Room.
Automatic Chip
Removal System. Cart Maintenance Station.

Supervisory
Supervisory

Computer
Ee

oO

i
20 600

Standby Paring.

Safequaring at the

sateguaring —-——
Within the MSIC Boring Module

+e ix Machining rs |

at ee te

on oof on
[ain cu jae res? PB
wee aoe J MY 9 SHS & bo eas
pei Upeted We

Figure 75. Areas to be considered for safeguarding


FON

Machine Tool
Control System

oe

System
Controiier —

Warning
ce Device
eS

Movable Guard
or Presence
Sensing Device

Figure 73. Typical manufacturing systemvceil using a robot as the matenai handling system

showing perime i interlocked gates, presence sensing
devices, warning devices, and additional system emergency stop devices

74


Cooperation and Assistance

Safety in the workplace demands cooperation and ale:
part. Supervisors. operators, and other workers who notice hazards in need
of safeguarding, or existing systems that need repair or improvement,
should notify the proper authority immediately.

ess an everyone's

Supervisors have these additional, speciai responsibilities with regard to
Safety in the workplace, encouraging safe work habits and correcting unsafe
ones; explaining to the worker all the potential hazards associated with the
machines and processes in the work area; and being responsive to
employer requests for action or information regarding machine hazards. The
first-line supervisor plays a pivotal role in communicating the safety needs of
the worker to management and the employer's safety rules and policies to
the worker.

Sometimes the solt

nto a machine safequarding problem may require
expertise that is not available in a given establishment. The readers of this
manual are encouraged to find out where heip is available and, when

necessary, to request it.

The machine's manufacturer is often a good piace to start when iookint
assistance with a safeguarding problem. Manui fers can often sup
necessary literature or advice. Insurance carriers, too. will often make their
safety specialists available to the establishments whose assets they insure.
Union safety specialists can also lend significant assistance.

Some government agencies offer consultation services, providing for on-site
evaluation of workpiaces and the recommendation of possible hazard
controls. OSHA funds one such program, which is offered free of charge to
employers in every state. Delivered by state governments or private
contractors, the consultation program is completely separate from the OSHA
inspection effort; no citations are issued and no penalties are proposed. The
trained professional consultants can help employers recognize hazards in
the workplace and can suggest general approaches for solving safety and
health problems. In addition. the consultant can identity sources of other
availabie heip, it necessary.

Anyone with questions about Federal standards, about the requirements for
machine safeguarding, or about available consultation services should
contact OSHA. (See the list of OSHA Regional Offices in the back of

this publication.)

79


Figure 36.
Pullback device on a
power press

MECHANISM

puueack / |

Pullback

Pullback devices utilize a series of c:
wrists, and/or arms. This type of det tr
stroking action. When the slide/ra een cycles, the operator is
allowed access to the point of operation. When the slide/ram begins to cycle
by starting its descent, a mechanical linkage automatically assures

withdrawal of the hands from the point of operation.

Figure 36 shows a pullback Gevice on a straight-side power press. When the
slide/ram is in the “up” position, the operator can feed material by hand into
6 point of operation. When the oress cycle is actuated, the operator's

lly withdrawn. Figure 37 shows a pullback

A pullback device on a press brake is illustrated in Figure 38.


Figure 18.
Interlocked guard on automatic
bread bagging machine

Figure 19.
interiocked guard on
picker machine

Figure 18 shows an interlocked barrier guard mounted on an automatic
bread bagging machine. When the guard is removed, the machine will
not function.

In Figure 19, the beater mechanism of a picker machine (used in the textile
covered by an interlocked barrier guard. This guard cannot be
is running, nor Gan ihe machine be restarted with

(Teele
re ee ee) ee
SS pa

17


Figure 27.
Self-adjusting guard on
radial arm saw

Figure 26 shows an adjustable enclosure guard on a bandsaw.

Self-Adjusting: The openings of these barriers 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 retums to
the rest position. This guard protects the operator by placing a barrier
between the danger area and the operator. The guards may be constructed
of plastic, metal, or other substantial material. Self-adjusting guards offer
different degrees of protection.

Examples of self-adjusting guards...

Figure 27 shows a radial arm saw with a self-adjusting guard. As the blade
is pulled across the stock, the guard moves up, staying in contact with
the stock.

Figure 28 shows a twin-action, transparent, self-adjusting guard. The first
guard rises as the stock enters, then retums to its rest position as the stock
moves ahead to raise the second guard.

A self-adjusting guard is shown in Figure 29. As the blade moves through
the stock, the guard rises up to the stock surface.

23


Figure 21.
Adjustable guard on
horizontal bandsaw

ADJUSTMENT KNOB

ip Figure 22, the bars adjust to accommodate the size and shape of the
cording to the

in Figure 25, the guard adjusts to provide a barrier between the operator anc
the biade.

19


|
| maaan

Nae

power press

Figure 38,
Pullback device on press brake

ray
n


Figure 14.
Fixed guards on a band saw

a barrier, protecting fingers from exposure to the blade. Note the side view

of the curved portion of the guard.

Figura 15.
Fixed guards on veneer clipper

i
|
i
|
i
I
|
i
i
i
|
A fixed guard is shown on a veneer clipper in Figure 15. This guard acts as |
i
i
|
i
i
|
i
I
|
i

14


Chapter 8

Ergonomic Considerations of
Machine Safeguarding

The ergonomic considerations of machine safeguarding are as significant to
the safety and health of the worker as are the multitude of techniques to
accomplish safety and health in the workplace. Worker stress and fatigue
can be averted by creditable work setups and well integrated safeguarding.
The various industry consensus standards are only now beginning to
address this issue. Future evaluations of safeguarding are likely to devote
more attention to this aspect.


Chapter 3

Guard Consiruction

Today many builders of single-purpose machines provide point-of-operation
and power transmission safeguards as standard equipment. However, not
all machines in use have built-in safeguards provided by the manufacturer.

Guards designed and installed by the builder offer two main advantages:

* They usually conform to the design and function of the machine.

° They can be designed to strengthen the machine in some way or to
serve some additional functionai purposes.

User-built guards are sometimes necessary for a variety of reasons. They
have these advantages:

* Often. with older machinery, they are the only practical
safeguarding solution.

« They may be the only choice for mechanical power transmission
apparatus in older plants. where machinery is not powered by
individual motor drives.

« They permit options for point-of-operation safeguards when skilled
personnel design and make them.

¢ They can be designed and built to fit unique and even
changing situations.

¢ They can be installed on individual dies and feeding mechanisms.

* Design and installation of machine safeguards by piant personnel
can help to promote safety consciousness in the workplace.

However, they also have disadvantages:

¢ User-built guards may not conform well to the configuration and
function of the machine.

* There is a risk that user-built guards may be poorly designed
or built.

Point-of-Operation Guards

Point-of-operation safeguarding is complicated by the number and
complexity of machines and also by the different uses for individual
machines. For these reasons, not all machine builders provide point-of-
operation guards on their products. in many cases a point-of-operation
guard can only be made and installed by the user after a thorough hazard
analysis of the work requirements. Poorly designed, built or installed guards
may create a hazard rather than eliminate one. To be effective they must
safeguard the employee while allowing the work to continue with minimum
disruption to the production process.

59


Figure 7.
Examples of dangerous

Examples of mechanisms involving cutting hazards include bandsaws,
circular saws, boring or drilling machines, tuming machines (lathes), or

Punching action results when power is applied to a slide (ram) for the
purpose of blanking, drawing, or stamping metal or other materials. The
danger of this type of action occurs at the point of operation where stock is
inserted, held, and withdrawn by hand.

yl
workers. See Figure 8.

Shearing action involves applying power to a slide or knife in order to trim or
shear metal or other materials. A hazard occurs at the point of operation
where stock is actually inserted, held, and withdrawn,

Bending action results when power is applied to a slide in order to draw or
stamp metal or other materials. A hazard occurs at the point of operation
where stock is inserted, held, and withdrawn.

Equipment that uses bending action includes power presses, press brakes,
and tubing benders. See Figure 10.


Figure 33.
Photoelectric presence-sensing
device on press brake

A photoelectric presence-sending device used with a press brake is
illustrated in Figure 33. The device may be swung up or down to
accommodate different production requirements.

The radiofrequency (capacitance) presence-sending device 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. Like the photoelectric
device, this device shall only be used on machines which can be stopped
before the worker can reach the danger area. This requires the machine to
have a friction clutch or other reliable means for stopping.

The electromechanical sensing device 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 fuil

predetermined distance, the con
machine cycle.

circuit does not te the

Figure 35 shows an eiectromechanical sensing device on an eyeletter. The
sensing probe in contact with the operator's finger is also shown.



Chapter 5

The Utilization of Industry
Consensus Standards

OSHA uses industry consensus standards, related to the safe operation of
equipment, as guidance of the industry accepted practice for sate
operations. Industry consensus standards which describe equipment
configuration or design but which do not describe safe and/or healthful use
and operation of the equipment are of limited assistance to OSHA. In any
event, even when an industry consensus standard addresses safety/health
considerations, OSHA may determine that the safety/neaith practices
described by that industry consensus standard are deficient when related to
the requirement(s) set fortn by the pertinent OSHA regulation(s). However,
many of the various ANS! safety standards devoted to the safe use of
equipment and machines are pertinent and provide valuable guidance as
they relate to the multitude of safe operating procedures regularly discussed
in ANSI safety standards.

All of the requirements of 29 CFR 1910.212, are applicable to machines
found in industry. Paragraph (a) (1), requires that employees be protected
from the hazards created by the point of operation, ingoing nip points, and
rotating parts. Paragraph (a) (2). describes the manner in which guards shall
be affixed. The proper application of devices are not described; therefore,
other similar OSHA or pertinent industry standards must be referred to for
guidance. Paragraph (a) (3) describes. with particularity, the requirements
for safeguarding the point of operation.

The OSHA standard specifically requires that at the point of operation, “the
guarding device shall be in conformity with any appropriate standards
therefore, or in the absence of applicable specific standards, shall be so
designed and constructed as to prevent the operator from having any part of
his body in the danger zone during the operating cycte." Applicable
standards include any similar OSHA standard or any OSHA adopted
industry consensus standard(s) which provide for the safety of the operator
during the operating cycle. However, any specific industry consensus
standard, such as an ANSI standard for the particular machine or
equipment, should be used for guidance relative to the accepted procedures
for safeguarding workers and operators from the recognized hazards of the
equipment.

Employers who comply with the requirements of an industry consensus
standard rather than a specific OSHA standard. where such compliance
deviates from the OSHA requirements but provides for a more conservative
safeguarding concept, are categorized as having created a de minimis
violation of the specific OSHA standard. (A de minimis violation is a violation
of an OSHA standard that has no direct or immediate relationship to safety
or health. Such de minimis violations require no correction and result in no

penalty.)

67


ANS! 8151.6-1982/88

ANSI B151.7-1982/88
ANS! B151.11-1982

ANSI B151.15-1985
ANSI B181.21-1986
ANSI B151.25-1988
ANSI B152.2-1982

ANSi 6153.1-1990
ANSI B155.1-1986
ANSI B169.1-1990
ANSI 8176-1985
ANSI B177.2-1977/82

ANSI/NEMA
1CS2:225.95-1983

ANSI/NFPA 79-1991
ANSI/RIA R15.06-1986
ANSI 28.1-1972

ANSI 2241.1-1989
ANSI Z241.2-1989
ANSI 2241.3-1989
ANSI 2245.1-1984
ANS] 2245.3-1977/83
ANSI Z245.5-1982
ANSI Z268.1-1082

69

Plastics Machinery, Slit Tape & Monofilament
Postextrusion Equipment

Plastics & Rubber Extrusion Machinery

Plastics Machinery, Granulators, Pelletizers,
& Dicers

Plastics Machinery, Extrusion Blow Molding
Plastics Machinery. Injection Blow Molding
Piastics Machinery, injection Moiding

Permanent-Moid Casting Machines (Other
than Gray iron)

Automotive Lifts

Packaging Machinery

Envelope Manufacturing Machinery
Copper-Alloy Diecasting

Printing ink Vertical Post Mixers

Interlocking Control Circuits for Personnel
Protection

Electrical Standard for Industrial Machinery
Industrial Robots and Robot Systems
Commercial Laundry & Dry-Cleaning Equipment
Foundry, Sand Prep., Maiding, & Core-Making
Foundry, Melting & Pouring of Metals

Foundry. Cleaning & Finishing of Castings
Refuse Collecting & Compacting Equipment
Stability of Refuse Bins

Baling Equipment

Metal Scrap Processing Equipment


Chapter 6

ohotic
WII tics

Robot Applications

Robots are machines that load and unload stock, assemble parts, transfer
objects, or perform other tasks.

Robots are used for replacing humans who were performing unsafe,
hazardous, highiy repetitive, and unpieasant tasks. They are utilized to
accomplish many different types of application functions such as material
handling, assembly, arc w g, machine too!

landing, assen 1g, 2 tool

load/untoad functions, painting/spraying, etc.

Studies in Sweden and Japan indicate that many robot accidents have not
occurred under normal operating conditions but rather during programming,
program touch-up, maintenance, repair, testing, setup, or adjustment. During
many of these operations, the operator, programmer or corrective

mainten: 2 worker may temoorarily be within the rabot's working envelope

where unintended operations could result i in injuries.

All industrial robots are either servo or non-servo controlled. Servo robots
are controlled through the use of sensors which are empioyed to continually

- tee eobot's axes for cositional and velocity feedback information.
f ihe robot's axes for positional and velocity feedback information.

im
This feedback information is compared on an on-going basis to pre-taught
information which has been programmed and stored in the robot's memory.

Non-servo robots do not have the feedback capability of monitoring the
robot's axes and velocity and comparing with a pre-taught program. Their
axes are controlled through a system of mechanical stops and limit switches

to contro} the robot's movement

to control the robot's movement.

Mechanical hazards might include workers colliding with equipment, being
crushed, or trapped by equipment, or being injured by falling equipment
components. For example, a worker could collide with the robot's arm or
peripheral equipment as a result of unpredicted movements, component

maifunctions, of unpredicted program changes.

A worker could be injured by being trapped between the robot's arm and

other peripheral equipment or being crushed by peripheral equipment as a
result of being impacted by the robot into this equipment.

Mechanical hazards also can result from the mechanical failure of
components associated with the robot c or ‘its power s Source, drive

end-effector power tools such as grinding wheels, buffing wheels, ‘deburring
tools, power screwdrivers. and nut runners to name a few.

71


—

/ yy

{ 2

See an

SK, tN \

> ae REST POSITION
a ge A
~ = ty’

ure gi
quard i is moved ‘from ‘the cutting head by the stock. After the stock is

removed, the guard will return, under spring tension, to the rest position.

Another type of self-adjusting guard mounted on a jointer is illustrated in

fed under the guard, ca:

the guard, cai

move vertically.

a Zé |

ee eS

Figure 30.

a jointer

Figure 21.
Figure 31.

a jointer


* report any hazards immediately to your supervisor;

* report to your supervisor any job-related illness or injury; and



Figure 2.
Common nip points on
rotating parts

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. In the latter case the stock fed between the rolls produces the nip
points. This danger is common on machines with intermeshing gears, rolling
mills, and calenders. See Figure 2.

Nip points are also created between rotating and tangentially moving parts.
Some examples would be: the point of contact between a power
transmission belt and its pulley, a chain and a sprocket, and a rack and
pinion. See Figure 3,

Nip points can occur between rotating and fixed parts which create a
shearing, crushing, or abrading action. Examples are: spoked handwheels or
flywheels, screw conveyors, or the periphery of an abrasive wheel and an
incorrectly adjusted work rest. See Figure 4.

Reciprocating motions may be hazardous because, during the back-and-
forth or up-and-down motion, a worker may be struck by or caught between
a moving and a stationary part. See Figure 5 for an example of a
reciprocating motion.

Transverse motion (movement in a straight, continuous line) creates a
hazard because a worker may be struck or caught in a pinch or shear point
by the moving part. See Figure 6.

Actions

Cutting action may invoive rotating, reciprocating, or transverse motion. The
danger of cutting action exists at the point of operation where finger, arm
and body injuries can occur and where flying chips or scrap material can

the area of the eyes or face. Such hazards are

nin cutting wood, metal, or other materials.



The basic types of hazardous mechanical motions and actions are:

Mi

* rotating (including in-running nip points)
* reciprocating
* transversing

Actions

ing
® punching

shearing

Motions

Rotating motion can be dangerous; even smooth, slowly rotating shafts can
grip clothing, and through mere skin contact force an arm or hand into a
dangerous position. Injuries due to contact with rotating parts can be severe.
Coaiiars, coupiings, cam
gears, and horizonta! np
gears, and horizontal or v

rotating mechanisms which may be hazardous. The danger i increases when
projections such as set screws, bolts, nicks, abrasions, and projecting keys

or set Screws are exposed on rotating parts, as shown in Figure 1.

Q

<\
_ 4 1]
i——>~TM Z/

ROTATING SHAFT AND PULLEYS WITH
PROJECTING KEY AND SET SCREW

|

nfm
Ne

om

Ty ya

ROTATING COUPLING WITH
PROJECTING BOLT HEADS

Figure 1.
Exampies of hazardous
Projections on rotating parts


Tu

THROAT AND GAP

GUARD

ante cua _—— |

SSS
NE

TM~

~.

maintenance or blade changes.

Figure 16 shows
power squaring

squaring shear

Fixed guard on a power


NG)
TRANSVERSE MOTION OF BELT

ample of transverse motion

tazardous reciprocating motion
Exa


Safety Requirements for the Construction, Care and Use of Drilling, Milling,
and Boring Machines, ANS{ B11.8-1985, American National Standards
Institute, New York

Safety Requirements for the Construction, Care, and Use of Horizontal

tion Molding ANS! 8151.1-1990, American Nationa!
Aolaing

Machines, ANS! 8151.1-1990, American National

Safety Requirements for the Construction, Care, and Use of Lathes, ANSI
B11.6-1984: American National Standards Institute, New York

5.1975: American Nationa! Standards Insti
.5-1975: American National Standards insti

afety Requiremenis for the Consiruction, Care, and Use of iron i Workers,
NS iY,
y

Safety Requirements for the Construction, Care. and Use of Mechanical
Power Presses, ANS! 811.1-1988: American National Standards Institute,
New York

Safety Requirements for the Construction, Care and Use of Metal Sawing

NS! B14.10-499: Nationa! Stan:
Machines, ANS! B11.10-1980: American Nationa! Stan

New York

Safety Requirements for the Construction, Care, and Use of Packaging and
Packaging-Related Converting Machinery, ANS! B155.1-1986: American
National Standards Institute, New York

Safety Requirements tion, Care, and Use of Power Press

Brakes, ANSI] B11.3-1982: American National Standards Institute, New York

Safety Requirements for the Construction, Care, and Use of Fasteners,
Rivet Setting Equipment, ANS! B154.1-1984: American National Standards
Institute, New York .

Safety Requirements for the Construction, Care, and Use of Single and
Multiple-Spindle Automatic Screw/Bar and Chucking Machines, ANSI
6811.13-1983: American National Standards Institute, New York

Safety Requirements for Woodworking Machin
American National Standards Institute, New York

Safety Specifications for Mills and Calenders in the Rubber and Plastics
Industries, ANS! B28.1-1967: American National Standards
Institute, New York

Standard Handbook for Mechanical Engineers, 9th ed: Baumeister,
Theodore, ed.; McGraw-Hill, 1987, New York

85


Related Publications

ANSV/ASME Standards

B11.2 Hydraulic Presses 1982

B11.3 Power Press Brakes 1982

B11.10 Metal Sawing Machines 1990

B11.11 Gear Cutting Machines 1985

811.12 Rall-forming and Roll-bending Machines 1983

B11.14 Coil Slitting Machines 1983

B1i1.15 Pipe, Tube, and Shape Bending Machines 1984
B11.16 Metal Powder Compacting Presses 1988

811.17 Horizontal Hydraulic Extrusion Presses 1982

811.18 Coiled Stee! Sheet & Plate Processing Machines 1985

Copies of the above can be obtained from the American National Standards Institute, 7 West 42nd Street,
New York, NY 10036, 13th Floor.

OSHA Publications

OSHA 2056 All About OSHA

OSHA 2019 Catalogue

OSHA 3000 Employer Rights & Responsibilities Following an OSHA Inspection
OSHA 3074 Hearing Conservation

OSHA 3021 OSHA: Employee Workplace Rights

Asingle free copy of the above materials can be obtained from OSHA field offices or OSHA Publications
Office, Room N3101, Washington, DC 20210, (202) 523-9667. Please send a self-addressed label with
your request.

SafeWorks. A one page periodic news sheet that provides a brief summary of the results of a small
business employer's request for workplace safety and health assistance from OSHA-funded
consultation services in all of the states and U.S. territories.

ErgoFacts. A one page news sheet that provides a brief summary of ergonomic hazards and the
need for workplace safety and health assistance.

The above publications can be obtained from the U.S. Department of Labor, OSHA-OICA, Room N3647,
Washington, DC 20210. Please send a self-addressed label with your request.

88


a . >
ag a5
gs Lo
3 235
Dc 2s
ts ue
8 Ss

3 E

2 a

- 3

s
2 2
<

21


<4
oS

U.S. Department of Labor
Occupational Safety and Health Administration

OSHA 3067
1992 (Revised)

enclose:





Figure 48.
Power press with gate

Figure 49.
Power press with
automatic feed

SCRAP MATERIAL


Requirements for Safeguards

What must a safeguard do to protect workers against mechanical hazards?
Safeguards must meet these minimum general requirements:

Prevent contact: The safeguard must prevent hands, arms, and any other
part of a worker's body from making contact with dangerous moving parts.
A good safeguarding system eliminates the possibility of the operator or

another worker placing parts of their bodies near hazardous moving parts.

Secure: 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 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.

Create no new hazards: A saieguard 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,
shouid be rolled or bolted in such a way that they eliminate sharp edges.

Create no interterence: 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 lubrication: if possible, one should be abie 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.

Nonmechanical Hazards

While this manual concentrates attention on concepts and techniques for
safeguarding mechanical motion, machines obviously present a variety of
other hazards which cannot be ignored. Full discussion of these matters is
beyond the scope of this publication, but some nonmechanical hazards are
briefly mentioned below to remind the reader of things other than
safeguarding moving parts that can affect the safe operation of machines.

All power sources for machines are potential sources of danger. When using
electrically powered or controlled machines, for instance, the equipment as
well as the electrical system itself must be properly grounded. Replacing
frayed, exposed. or old wiring will also help to protect the operator and
others from electrical shocks or electrocution. High pressure systems, too,
need careful inspection and maintenance to prevent possible failure from
pulsation, vibration. or leaks. Such a failure could cause. among other
things, explosions or flying objects.


\ \ 7 —
| \

88 oe s2
o s
38 ae 25
2® AS q
re ira) & i]
aD
£
S

Typical pun
Typical pu


Figure 68.
Use of push stick or push block

Special hand tools may be used to place or remove stock, particularly from
Or into the point of operation of a machine. A typical use would be for
reaching into the danger area of a press or press brake. Figure 67 shows an
assortment of tools for this purpose. Holding tools should not be used
instead of other machine safeguards; they are merely a supplement to the
protection that other guards provide.

A push stick or block, such as those in Figure 68, may be used when
feeding stock into a saw blade. When it becomes necessary for hands to be
in close proximity to the blade, the push stick or block may provide a few
inches of safety and prevent a severe injury. In the illustration the push block
fits over the fence.

m~*
a Econ

wee PUSH STICK
— USMS PUSH BLOCK

57


Devices

Method
Safety tnp controls:

Pressure-sensitive
bady bar

Safety triprod
Safety triowire

Two-hand control

Two-nand trip

Gate

Sateguarding Action

Stops machine when tripped

Concurrent use of both
hands is required, preventing
the operator from entering
the danger area

Concurrent use of two hands
on separate contrais.
prevents hands from being in
danger area when machine
cycle starts

Provides a barrier between
danger area and operator or
other personnel

Advantages

Simplicity of use

Operator's hands are ata
Pre-determined location

Operator's hands are free to
pick up a new part after first
half of cycle is completed

Operator's hands are away
from danger area

Can be adapted ta multipte
operations

No obstruction to hand
feeding

Does not require adjustment
for each operation

Can prevent reaching into or
walking into the danger area

40

Limitations

All controls must be manually
activated

May be difficult to activate
controls because of their
location

Only protects the operator

May require special fixtures
to hold work

May require a machine brake

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

Operator may try to reach
into danger area after
tripping machine

Some trips can be rendered
unsafe by holding with arm or
blocking, thereby permitting
one-hand operation

Protects only the operator

May require special fixtures

May require frequent
inspection and regular
maintenance

May intertere with operator's
ability to see the work


Commissioner

Alaska Department of Labor
P.O. Box 21149

Juneau, AK 99801

(907) 465-2700

Olrector

Industral Commission of Arizona
800 W. Washington

Phoenix, AZ 85007

(602) 542-5795

Director

Califorma Department of Industrial Relations
455 Golden Gate Avenue

th Floor

S. San Francisco, CA 94102

(415) 703-4590

Commissioner

Connecticut Department of Labor
206 Foily Brook Boulevard
Wethersfield, CT 06109

(203) 566-5123

Director

Hawaii Department of Labor and
industnai Reiations

830 Punchbowl Street

Honoiuiu, Hl 96813

(808) 548-3150

Commissioner

indiana Department of Labor
1013 State Office Building
100 North Senate Avenue
Indianapolis. IN 46204-2287,
(317) 232-2665
Commissioner

fowa Division of Labor Services
1000 E. Grand Avenue

Des Moines. 1A 50319

(515) 281-3447

Commissioner

Workplace Standards

Kentucky Labor Cabinet

1049 U.S. Highway, 127

South Frankiont, KY 40604

(502) 564-3070

Commissioner

Maryland Division of Labor and Industry
Deparment of Licensing and Regulation
501 Si. Paui Piace. 2nd Fioor

Baltimore, MD 21202-2272

{301) 333-4179

Director

Michigan Department of Labor
Victor Office Center

201 N. Washington Square
P.O, Box 20015

Lansing,

1 48933
(517) 373-9600

Director

Michigan Oepartment of Public Health
3423 North Logan Street

Box 30195

Lansing, Mi 48909

(517) 335-8022

Commissioner
Minnesota Deparment of Labor and industry

(612) 296-2042

Director

Nevada Department of Industrial Relations
Division of Occupational Safety and Health
Capitol Compiex

1370 S. Curry Street

Carson City, NV 89710

£702) 687-3032

Secretary

New Mexico Enviranment Dept.
Occupational Health and Safety Bureau
1190 St. Francis Orive

P.O, Box 26110

Santa Fe. NM 87502

(505) 827-2850

Commissioner

New York Department of Labor
State Office Building

Campus 12- Room 457
Albany, NY 12240

(518) 457-2741

Commissioner

North Carolina Department of Labor
4 West Edenton Street

Raleigh, NC 27601

{819)733-7166

Administrator
Oregon Occupational Safety
and Health Division

Oregon Deoarment of insurance and Finance,

Room 160

Labor and industries Building
Salem, OR 97310
{503)378-3272

Secretary

Puerto Rico Department of Labor and
Human Resources

Prudencio Rivera Martinez Building
505 Munoz Rivera Avenue

Hato Rey, PR 00918

(809) 754-2119

Commissioner

South Carolina Department of Labor
3600 Forest Drive

P.O. Box 11329

Columora, SC 29211-1329

(803) 734-9594

86

h Approved Plans

Commissioner

Tennessee Department of Labor
501 Union Buiiding

‘Suite “A”, 2nd Floor

Nashville, TN 37243-0655

(615) 741-2582,

Administrator
Utah Occupational Safety and Heaith

P.O. Box 5800
Salt Lake City, UT 84110-5800
(801) 530-6900

Commissioner

Vermont Department of Labor and tndustry
120 State Street

Montpelier, VT 05620

(802) 828-2765

Commissioner
irgin islands Depar

Christiansted
St. Croix, Vi 00840-4668
(809) 773-1994

Commissioner

Virginia Department of Labor and Industry
Powers-Taylor Building

19S. 13th Street

Richmond, VA 23219

(804) 786-2376

Director

Washington Department of
Labor and industries
General Administration
Building

Room 334-AX-31

Olympia, WA 98504-0631
(206) 753-6307

Olrector

Department of Employment
Division of Employment Affairs
Occupational Safety and
Health Administration
Herschler Building

2nd Floor East

122 West 25th Street
Cheyenne, WY 82002

(307) 777-7786 or 777-7787


Devices

A saiety device may perform one of severai functions. it may stop the
machine if a hand or any part of the body is S macverenty placed in the

19
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.

Presence-Sensing

resence-sensing device uses a system of light
resence sing device uses a system of light

ur controls which can interrupt the machine's operating cycle. If
the light field is broken. the machine stops and will not cycle. This device
must be used only on machines which can be stopped before the worker
can reach the danger area. The design and placement oft the > guard depends

Figure 32 shows a photoelectric presence-sending device on a part-
revolution power press. Wher, the light beam is broken, either the ram will
not start to cycle. or, if the cycle has begun. the stopping mechanism will be

Figure 32.
Photoelectric presence-sensing
device on power press

[See

f
A
\

SANGER AREA

SENSING DEVICE

28


Figure 50.
Saw with automatic

indexing mechanism and Figure 50 shows a saw with an automatic indexing mechanism that moves
traveling head the stock a predetermined distance for each cut. The traveling head

automatically recycles for each cut.

With semiautomatic feeding, as in the case of a power press, the operator
uses a mechanism to place the piece being processed under the ram at
each stroke. The operator does not need to reach into the danger area, and
the danger area is completely enclosed.

45


Guards

Methad

Fixed

Safeguarding Action

Provides a barrier

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

interlocked

Shuts off or disengages
power and prevents
starting of machine when
guard is open; shouid
require the machine to be
stopped before the worker
can reach into the danger
area

Can provide maximum
protection

Allows access to machine
for removing jams without
time consuming removal
of fixed guards

Requires careful
adjustment and
maintenance

May be easy to
disengage jams

Adjustable

Provides a barrier that
may be adjusted to
facilitate a variety of
production operations

Can be constructed to suit
many specific applications
Can be adjusted to admit
varying sizes of stock

Hands may enter danger
area — protection may not
be complete at ail times
May require frequent
maintenance and/or
adjustment

The guard may be made
ineffective by the operator

May interfere with visibility

Seif-adjusting

Provides a barrier that
moves according to the
size of the stock entering
the danger area

Off-the-shelf guards are
often cammercially
available

Does not always provide
maximum protection

May interfere with visibility
May require frequent

maintenance and
adjustment

27


Figure 72.

implemen

lockoutfagout requir aments

Oaverop Documented

Lockout Tagout Procedure:
kouYT agout Proceaure

t

Develop Training Program

£ +

+

Prowda Training 10 Provide Detaled Program
Affected Employees to Authorized Employees

Prove Training 10
AB Other Employees:

T
ad
‘Assign Mamtenance/Sence
Task to Autnonzed Employees|

‘Consult Company Notity Affected Employea(s) |
Procedures Document of Maintenence/Servics Ops |

loentty
Enargy isolating Devices
¥

identty and Obtain

Lockoul/Tagout Devices

—————

Deactivate and Tagout Deactivata and Lockout

¥
Very Hazardous
Energy Controlled

Lo Hazaraous Energy i <tr>
‘Mot Controted

Not Controtisd ¥

Periorm Task

x
Verity Parsonnet
Clear and Accounted For

Remove LockouvTagout

— =

Retum Custogy of Equiement Restore Power &
Retum Custody of Equipment 1) Restore Power &
to Affected Emolovee(s) Verity Ops

ye
Probiem identified 7

used machine parts and hardware kept in stock so that the crews ate ‘not
encouraged (even obliged) to improvise, at the risk of doing an unsafe
repair, or to postpone a repair job? And don't overlook the possibility that
maintenance equipment itself may need guarding of some sort. The same
precaution applies to tocis and machines used in the repair shop. Certainiy,
the maintenance and repair crew are entitled to the same protection that

their service provides to the machine operators in the plant.

65



Ni POINT ——

YR

~
A, © 2 O \s
Ze OY

CD yo}
a NOKe

NiP POint QO NS J

longitudinal motions

i
1
|
i
|
i
|
i
|
i
|
i
|
!

Figure 4.

Nip points between rotating
machine components:

(4~ cover removed for clarity.)



In Figure 20, an interlocked guard covers the rotating cylinder of the dividing
head of a roll make-up machine used for making hamburger and
hot-dog rolls.

Adjustable: Adjustable guards are useful because they allow flexibility in
accommodating various sizes of stock.

dsaw with an adju:
i f the blade.

bie Guard to protect the Operator
Ss guard can be adjusted according

x

to the size of stoci

Figure 20,
interlocked guard on roif

make-up machine


U.S Department of Labor
Regional Offices for the

Occupational Safety and Health Administration

Contact the OSHA Regional Office nearest you for the location of your

OSHA Area Office

Region

(CT,* MA, ME, NH, RI, VT")
133 Portland Street

1st Floor

Boston, MA 02114
Telephone: (617) 565-7164

Region ll

(NJ, NY," PR,” VI")

201 Varick Street

Room 670

New York, NY 10014
Telephone: (212) 337-2378

Region Ill

(DC, DE, MD," PA, VA." WV)
Gateway Building, Suite 2100
3535 Market Street
Philadeiphia, PA 19104
Telephone: (215) 596-1201

Region IV

{AL, FL, GA, KY,° MS, NC,”
SC," TN")

1375 Peachtree Street, N.E.
Suite 587

Atlanta, GA 30367
Telephone: (404) 347-3573

Region V

(iL, IN," MI,” MN," OH, WI)
230 South Dearborn Street
Room 3244

Chicago, IL 60604
Telephone: (312) 353-2220

Region VI

(AR, LA, NM,* OK, TX)
525 Griffin Street

Room 602

Dallas, TX 75202
Telephone: (214) 767-4731

Region Vil

(IA,* KS, MO, NE)

911 Walnut Street, Room 406
Kansas City, MO 64106
Telephone: (816) 426-5861

Region Viii

(CO, MT, ND. SD, UT," WY*)
Federal Building, Room 1576
1961 Stout Street

Denver, CO 80294
Telephone: (303) 844-3061

Region Ix
(American Samoa, AZ," CA,"
Guam, Hi,” NV,* Trust
Territories

of the Pacific)

71 Stevenson Street

Room 415

San Francisco, CA 94105
Telephone: (415) 744-6670

Region X

{AK,* iD, OR," WA")

1111 Thira Avenue

Suite 715

Seattle, WA 98101-3212
Telephone: (206) 553-5930

“These states and territories operate their own OSHA-approved job safety and health
programs (Connecticut and New York plans cover public employees only). States
with approved programs must have a standard that is identical to, or at least as

effective as, the federal standard.

@ U.S. GOVERNMENT PRINTING OFFICE:1992.312-41 0764867


fw J etd NN

Figure 65.
Awareness barrier on
Stitching machine

Figure 66.
Other applications of shieids

TRANSPARENT ~

r= || — suet
i

oO
a


The following texts were used for reference in compiling this manual, This
does not constitute an endorsement of the texts by the U.S. Department
of Labor.

Accident Prevention Manual for Industrial Operations, 9th ed. National
Safety Councii, 1988, Chicago

Alph:
1990-91, Chicago

Cabinetmaking and Millwork: Feirer, John; Glenco Publishing Co.,
Peoria, IL

Dictionary of Terms Used in the Safety Professior: Tarrants, W.E., ed.;
American Society of Safety Engineers, 1988, Park Ridge, IL

Dise Grinding-Sate Rules and Methods. Grinding Wheel Institute, Cleveland

Electrical Standard for Metalworking Machine Tools, NFPA 79: National Fire
Protection Association, 1987, Quincy, MA

Fundamentals of Industrial Hygiene: Olishifski

E., eds.; National Safety Council, 1988, Chicago

Jufian B. and McElroy, Frank

General Industry Safety and Health Standards, Title 29 Code of Federal
Regulations 1910.212-1910.222

Guards Ii/ustrated, National Safety Council, 1987, Chicago
Industrial Ventilation, A Manual of Recommended Practice, 20th ed.:

American Conference of Governmental Industrial Hygienists, Edward
Brothers, 1988, Lansing, MI

rentice Hail,

Machine Tool Practice, White, Warren T., Kidbe, Richard
1991, New York

Power Press Safety Manual, National Safety Council, 1989, Chicago

Safeguarding of Machinery, BS 5304: British Standards Institute,
1975, London

The Use, Care, and Protection of Abrasive Wheels, ANSI B7.1-1988:

American National Standards Institute. New Yo:
American National Standards Institute, New York

Safety Recommendations for Grinding Wheel Operatior. Grinding Wheel
Institute, Cleveland

Safety Requiremenis for the Consiruction, Care and Use of Cold Headers
a ere ANGI OQ47 7.4005 Armarican Natignal Standarde
11.7-1985, American National Standards

84

National Safety Council,


Figure 71.
Lockout vaive

Mechanical: Figure 70 shows satety blocks being used as an additional
safeguard on a mechanical power press, even though the machine has been
locked out. The safety blocks prevent the ram from coming down under its
own weight.

Pneumatic and hydrautic: Figure 71 shows a lockout valve. The lever-
operated air valve used during repair or shutdown to keep a pneumatic-
powered machine or its components from operating can be locked open or
shut. Before the valve can be opened, everyone working on the machine
must use his or her own key to release the lockout. A sliding-sieeve valve
exhausts line pressure at the same time it cuts off the air supply. Vaives
used to lock out pneumatic or hydraulic-powered machines should be

TO MACHINE,

—— ~
0 ebtone i ei

VALVE ON

With the vaive fever in the
“ON position, air frora the
main supply line tows
through the vaive into the
machine's operating

avr tines

FROM MACHINE FROM AIR SUPPLY
— ‘ —s

FREE A TEON, [wie Te
faroseneae ome S5umE

VALVE OFF

Moving the ‘ever to “OFF”
cuts off all air supply to the
machine. At the same time,
exnaust ports are ovened.
bleeding alt air pressure in
the machine to atmosonere

Automatic bleeder vaive
focked in “OFF” position
with padiocks of four
employees

63


TRIPROO

Figure 41.
Safety triprod on a rubber mill

35


Machine

Answers to the following questions should heip the interested reader determine the safeguarding needs of his or her own

workplace, by drawing attention to hazardous conditions or practices requiring correction.

Requirements for Aii Safeguards

1, Do the safeguards provided meet the minimum OSHA requirements?
2. Do the safeguards prevent workers’ hands. arms, and other body parts from making contact with
dangerous moving parts?

3. Are the safeguards firmly secured and not easily removable?

Do the safeguards ensure thai no obdjécts will faii into ine is?
De the safeguards permit safe. comfortable. and
Do the safeguards permit safe, comfortable, and
Can the machine be olled without removing the safeguard?

Is there a system for shutting down the machinery before safeguards are removed?
Can the ex:sting safeguards be improved?

ONOmE

Mechanicai Hazards

he point of operation:
Is there a point-of-operation safeguard provided for the machine?
f

T
1.

2. oes it keep ihe operaior's hands. fingers. body out of the danger area?

2. Is there evidence that the safequards have been tampered w: or removed?
3. Is there evidence that the safeguards have been tampered with or removed?
4. Could you suggest a more practical, effective safeguard?

§. Could changes be made on the machine to eliminate the point-of-operation hazard entirely?
Power tt

1,

2. Are there any exposed beits or chain dnves?

3. Are there any exposed set screws, key ways, collars, etc.?

4. Are starting and stopping controls within easy reach of the operator?

§. if there is more than one operator. are separate controls provided?

Other moving parts:
1. Are safeguards provided for all hazardous moving parts of the machine including auxiliary parts?

Nonmechanical Hazards

1. Have appropriate measures been taken to safeguard workers against noise hazards?

2. Have special guards. enclosures. or personal protective equipment been provided, where
necessary, to protect workers from exposure to harmful substances used in machine operation?

Electric Hazards

1. Is the machine instatled in accordance with National Fire Protection Association and National
Eleciricai Code requirements?

Are there loose conduit fittings?

Is the machine properly grounded?

Is the power supply correctly fused and protected?
Do workers occasionally receive minor shocks while operating any of the machines?

pReN

80

|
|

PEI d tl

Pl ld]
L1ttl

Plt dl
Pld dd

Filth

lo

eee

bid dl


Safety triprod on a bread

aemnbae mnmnbinn
biccler machine

Figura 42.

36


PLUNGER HANDLE

UN RETRACTED POSITION) ro
/ cuecrontes | J
/ fener iron | |
Pee LER fo)
Sa yu \\ q]
a

=

SALE

Figure 60. [(O)
Semiautomatic ejection
mechanism
Figure 61.
Robot movement capability
os oA ROTARY
TRAVERSE
els
C5

RADIAL
TRAVERSE LTE
a 4 ~ VERTICAL

Bel a ca

WRIST
geno ~*

wast

ds SWIVEL
Hl

WRIST

Yaw


_exkge al

SQ AZ"
UNE SECOND GUARD
NR Figure 28.
Self-adjusting guard on

Ma

24


Miscellaneous Aids

While these aids do not give complete protection from machine hazards,
they may provide the operator with an extra margin of safety. Sound
judgment is needed in their application and usage. Below are several
exampies of possible applications.

An awareness barrier does not provide physica! protection, but serves only
to remind a person that he or she is approaching the danger area.
Generally. awareness barriers are not considered adequate when continual
exposure to the hazard exists.

Figure 64 shows a rope used as an awareness barrier on the rear of a
power squaring shear. Although the barrier does not physically prevent a
person from entering the danger area, it calls attention to it. For an
employee to enter the danger area. an overt act must take place, that is, the
employee must either reach or step over, under or through the barrier.

Figure 65 shows an awareness barrier on a stitching machine.

lds, another aid, may be used to provide protection from flying particies.
spiashing cutting oils. or coolants. Figure 66 shows several
potential applications.

Figure 64.
Rear view of power
shearing square

k AWARENESS
| BARRIER

54


designed to accept locks or iockout adapters and snouid be capable of
“bleeding off pressure residues that could cause any pat of the machine
to move.

In shops where several maintenance persons might be working on the same

machine, multiple lockout devices accommodating several padlocks are
used. The machine cannot be reactivated until each person removes his or
her jock. As a matter of generai policy. !ockout control is gained by the
procedure of issuing personal padlocks to each maintenance or repair

person; no one but that person can remove the padiock, thereby each

¢

Whenever machines or equipment are serviced, there are hazards
encountered by the employees performing the servicing or maintenance
which are unique to the repair or maintenance procedures being conducted.
These hazards may exist due to the faiiure of the empioyees doing the
servicing or maintenance to stop the machine being worked on. Even i

machine has been stopped. the machine can still be hazardous due to the
ity ofthe machine becor fe] reenergized or rast:

g.

In order to prevent these hazards. each machine or piece of equipment
should be safeguarded during the conduct of servicing or maintenance by:
(1) notifying all affected employees. (usually machine or equipment operators

or users) inat

ie Macn:

tagging out the energy source; (s) ‘elieving any stored or residual energy;
and (6) verifying that the machine or equipment is isolated from the energy
source. Although this is the general ruie, there are exceptions when the
servicing or maintenance is not hazardous for an employee. when the

servicing which is conducted is minor in nature, done as an integral part of
production, and the employer utilizes alternative safeguards which provide
effective protection as is required hy 29 CFR 1910.212 or other specific

effective protect required by 29 0.212 or other specifi

OSHA standards.

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 é@ steps inciude t a) inspection of the machine or equipment to ensure

or equipment will not. endanger employees. (3) removal of the iockout
devices, (4) reenergization of the machine or equipment, and (5) notification
of affected employees that the machine or equipment may be returned
to service.

The steps to lockout described above are only a part of the total energy

atrol proaram which must exist in the workplace. in addition. the emolov:

contro! progr 2. In addition. the employee
should have w: procedures for all eq:

wi

ust exist ir

id npr " eq yees
must be trained in their duties and responsibilities under the energy ‘control
program and periodic inspections must be conducted to maintain ‘the
effectiveness of the program.

the equipment must be isolated and locked out.

64


Introduction

This manual has been prepared as an aid to employers. employees,
machine manufacturers. machine guard designers and fabricators, and all
others with an interest in protecting workers against the hazards of moving
machine parts. It identifies the major mechanical motions and the general
principles of safeguarding them. Current applications of each technique are
shown in accompanying illustrations of specific operations and machines.
The methods described here may be transferred. with due care, to different
machines with similar hazards, To determine whether or not safeguarding
meets the requirements of the standard, any mechanical motion that
threatens a worker's safety should not remain unguarded.

The approaches to machine safeguarding discussed in this manual are not
the only solutions which meet the requirements of the standard. Why?
Because practical solutions to safeguarding moving machine parts are as
numerous as the people working on them. No publication could keep pace
with all of these solutions or attempt to depict them all.

In machine safeguarding. as in other regulated areas of the American
workplace, to a certain extent OSHA standards govem function and practice.
This text. however. is not a substitute for the standards. It is a manual of
basic technical information and workable ideas which the employer may use
as a guide to achieving compliance. It offers an overview of the machine
safeguarding problem in the industrial setting, an assortment of solutions in
popular use, and a challenge to all whose work involves machines.

Many readers of this manual already have the judgment. knowledge, and
skill to deveiop effective answers to problems yet unsoived. innovators are
encouraged to find here stimulation to eliminate mechanical hazards facing
America’s workers today.


operation of the machine. This may be accomplished by locating a machine
so that the hazardous parts of the machine are located away from operator
work stations or other areas where employees walk or work. This can be
accomplished by positioning a machine with its power transmission
apparatus against a wall and leaving ail routine operations conducted on the
other side of the machine. Additionally, enclosure wails or fences can 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.

The feeding process can be safeguarded by location if a safe distance can
be maintained to protect the worker's hands. The dimensions of the stock
being worked on may provide adequate safety.

Far instance, if the stock is several feet long and only one end of the stock is
being worked on, the operator may be abie to hoid the opposite end while
the work is being performed. An example would be a single-end punching
machine. However, depending upon the machine, protection might still be
required for other personnel.

The positioning of the operator's control station provides another potential
approach to safeguarding by location. Operator controls may be located at a
safe distance trom the machine if there is no reason for the operator to

tend it.

Feeding and Ejection Methods to improve
Operator Safety

Many feeding and ejection methods do not require the operator to place his
or her 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 any operator involvement
after the machine starts to function.

Some feeding and ejection methods may even create hazards themselves.
For instance, a robot may eliminate the need for an operator to be near the
machine but may create a new hazard itself by the movement of its arm.

Using these feeding and ejection methods does not eliminate the need for
guards and devices. Guards and devices must be used wherever they are
necessary and possible in order to provide protection from exposure

to hazards.

Types of feeding and ejection methods...
Automatic feeds reduce the exposure of the operator during the work
process, and sometimes do not require any effort by the operator after the

machine is set up and running.

in Figure 49, the power press has an automatic feeding mechanism. Notice
the transparent fixed enclosure guard at the danger area.


Figure 46.
Two-hand controi buttons
of full-revolution clutch

Two-Hand Trip

The two-hand trip in Figure 46 requires concurrent application of both the
operator's control buttons to activate the machine cyctle. after which the hands
are free. This device is usually 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 operator to move his or her hands
from the trip buttons or handies into the point of operation before tne first

half of the cycle is completed. The distance from the trip button depends
operator's hands are kept far cnough. away to prevent en from being
placed in the danger area prior to the slide/ram or blade reaching the full
“down" position.

To be effective, both two-hand controls and trids must be located so that the
operator cannot use two hands or one hand and another part of his/her body
operator cannot use two hands or one hand and another pant of his/her body

41


OSHA encourages employers to abide by the more current industry
consensus standards since those standards are more likely to be abreast of
the state of the art than an appiicabie OSHA standard may be. Furthermore,
the industry consensus standards will usually discuss a variety of techniques
for averting exposure to the identified hazards of the machine or process.

Listing of Specific ANSI Safety Standards

ANSI B11.1-1982
ANSI B11.2-1982
ANSI B11.3-1982
ANSI B11.4-1983
ANS! B11.5-1988
ANS! B11.6-1984
ANSI 811.7-1985
ANSI B11.8-1983
ANS! B11.9-1975
ANSI B11.10-1983
ANSI B11.11-1985
ANSI B11.12-1983
ANSI B11.13-1983

ANS! 811.14-1983
ANSI B11.15-1984
ANS! B11.17-1982
ANSI 811.18-1985

ANSI B11.19-1990
ANS! 811.20-1991
(ANSI B15.1-1994/6)
ANSI B19.1-1990
ANSI B19.3-1986/90
ANSI B20.1-1990
ANSI 824.1-1985
ANSI B28,6-1983
ANSI B28.7-1983
ANSI B28.8-1983
ANSI B28,9-1983
ANS! B28.10-1986
ANSI 830. 16-1987
ANSI B151.1-1990
ANSI B151.2-1982/88
ANSI B151.3-1982/88
ANSI B151.4-1982/88

ANSI B151.5-1982/88

Mechanical Power Presses
Hydraulic Power Presses

Power Prec 3 Brakes

Shears

tron Workers

Lathes

Cold Headers and Coid Formers
Drilling, Milling, and Boring Machines
Grinding Machines

Meta! Sawing Machines

Gear Cutting Machines

Roll Forming and Roll Bending Machines

Single- and Multiple-Spindie Automatic
Screw/Bar and Chucking Machines

Coil Slitting Machines/Equipment
Pipe, Tube, and Shape Bending Machines
Horizontal Hydraulic Extrusion Presses

Machinery and Machine Systems for the
Processing of Coiled Strip, Sheet, and Plate

Machine Tools, Safeguarding
Manufacturing Systems/Cells

Power Transmission Apparatus

Air Compressor Systems
Compressors for Process industnes
Conveyors and Related Equipment
Forging Machinery

Rubber Machinery, Hose

Rubber Machinery, Hose

Rubber Machinery, Hose

Rubber Machinery, Hose

Rubber Machinery, Endless Belt
Overhead Hoists

Plastics injection Molding Machinery. Horizontal
Piastics Machinery, Fiim Casting
Plastics Machinery, Screen Changers

Plastics Machinery, Blown Film Takeoff &
Auxiliary Equipment
Plastics Machinery, Film & Sheet Winding

68


Chapter 2

Methods of Machine

There are many ways to safeguard machines. The type of operation, the
size or shape of stock, the method of handling, the physical layout of the
work area, the type of material, and production requirements or {imitations
will help to determine the appropriate safeguarding method for the individual
machine.

As a general rule, power transmission apparatus is best protected by fixed
guards that enclose the danger areas. For hazards at the point of operation,
where moving parts actually perform work on stock, several kinds of
safeguarding may be possible. One must always choose the most effective
and practical means available.

We can group safeguards under five general classifications.

1. Guards
A. Fixed
8. Interiocked
C. Adjustable
O. Self-adjusting

2. Devices
A. Presence Sensing
(1) Photoelectrical (optical)
(2) Radiofrequency (capacitance)
(3) Electromechanical
B. Pullback
C. Restraint
0. Safety Controls
(1) Safety trip contro!
(a) Pressure-sensitive body bar
{b) Safety tnpod
{c) Safety tripwire cable
(2) Two-hand control
(3) Two-hand trip
E. Gates
(1) interlocked
(2) Other
3. Location/Distance
4. Potential Feeding and Ejection Methods to Improve Safety for
the Operator
A. Automatic feed
B. Semi-automatic feed
C. Automatic ejection
0. Semi-automatic ejection

a
a


Feeding and Ejection Methods

Method

Automatic Feed

Semiautomatic Feed

Automatic Ejection

Semiautomatic Ejection

Robots

Safeguarding Action

Stock is fed from rolls,
indexed by machine
mechanism, etc.

Stock is fed by chutes,
movable dies. dial feed,
plungers, or sliding bolster

Work pieces are ejected by
air or mechanical means

Work pieces are ejected by

mechanical means which are

initiated by the operator

They perform work usually
done by operator

53

Advantages

Eliminates the need for
operator invoivement in the
danger area

Operator does not nave to
enter danger area to remove
finished work

Operator does not have to
enter danger area

Are suitable for operations
where high stress factors are
present. such as heat and
noise

Limitations

Other guards are also
required for operator
protection — usually fixed
barrier guards

Requires frequent
maintenance

May not be adaptable to
stock variation

May create a hazard of
blowing chips or debris

Size of stock limits the use
this method

Air ejection may present a
noise hazard

Other guards are required
operator protection

May not be adaptable to
stock variation

Can create hazards
themselves

Require maximum
maintenance

Are suitable only to specif
operations


Mechanical Power Transmission
Apparatus Guarding

icant difference between power transmission guards and point-of-
operation guards is that the former type needs no opening for feeding stock.
The only openings necessary for power transmission guards are those for
lubrication, adjustment, repair, and inspection. These openings should be
provided with interlocked covers that cannot be removed except by using
tools for service or adjustment.

To be effective, power transmission guards should cover all moving parts in
such a manner that no part of the operator's body can come in contact
with them.

Guard Material

Under many circumstances, metal is the best material for guards. Guard
framework is usually made from structural shapes, pipe, bar, or rod stock.
Filler material generally is expanded or perforated or solid sheet metal or
wire mesh. It may be feasible to use plastic or safety glass where visibility
is required.

Guards made of wood generaily are not recommended because of their

flammability and lack of durability and strength. However, in areas where
corrosive materials are present, wooden guards may be the better choice.

60


Figure 12.
Fixed guard on egg

carton folding machine

Figure 13.
Fixed guard enclosing
belt and pulleys

ixed guard that protects the operater from a mechanism
th: guard would not normaily be removed except to
perform maintenance on the machine. Figure 13 shows a fixed enclosure
guard shielding the belt and pulley of a power transmission unit. An

inspection panel is provided on top in order to minimize the need for

not be

closure

removed while the mechanis:
guards are shown on a bandsaw. These guards protect the operator from
the tuming wheels and moving saw blade. Normally, the only time for the
guards to ‘be opened or removed would be for a blade change or
maintenance. It is very important that they be securely fastened while the
saw is in use.

13


Table of Contents

Introduction
Chapter
1 Basics of Machine Safeguarding
2 Methods of Machine Safeguarding

3. Guard Construction............

4 Machinery Maintenance and Repair
5 Utilization of industry Consensus Standards
6 Robotics in the Workplace

7 Celiylar Manufacturing Systems

8 Ergonomic Considerations of Machine Safeguarding...............

9 Cooperation and Assistance

Machine Guarding Checklist ..

Worker Rights and Responsibilities
Bibliography ....

States with Approved Pians
OSHA Consultation Project Directory

Related Publications



———

i | VQ oy ban
i \ \\ \ | W

Safety Trip Controls

Safety trip controls provide a quick means for deactivating the machine in an
emergency situation.

A pressuré-sensitive body bar, when depressed. will deactivate the machine.
If the operator or anyone trips, loses baiance, or is drawn toward the
machine, applying pressure to the bar will stop the operation. The
positioning of the bar, therefore, is critical. It must stop the machine before a
part of the employee's body reaches the danger area. Figure 40 shows a
pressure-sensitive body bar tocated on the front of a rubber mili.

When pressed by hand, the safety deactivates the machine. Because the
triprod has to be actuated by the operator during an emergency situation, its
proper position is also critical. Figure 41 shows a triprod iocated above the
tubber mill. Figure 42 shows another application of a triprod.

Safety tripwire cables are located around the perimeter of or near the danger
area. The operator must be abie to reach the cable with either hand to stop
the machine. Figure 43 shows a calender equipped with this type of control,
while Figure 44 shows a tomato sorter with a safety tripwire cable.

Figure 40.

Pressure-sensitive body bar on

a rubber mill


ry

Parson

Do operators and maintenance workers have the necessary training in how to use the safeguards
and why?
Have operators and maintenance workers been trained in where the safeguards are located. how

and what hazards they protect against?

they provide protectio
Have operators and
can be removed?
Have workers been trained in the procedures to follow if they notice guards that are damaged,
missing, or inadequate?

Protective Equipment and Proper Clothing
is protective equipment required?
it protective equipment is required, is it appropriate for the job, in good condition, kept
clean and sanitary, and stored carefully v when 0 not in use?

dressed safely for the o loase-fitting clothing or jewelry)?
Machinery Maintenance and Repair

Have maintenance workers received up-to-date instruction on the machines they service?
Do maintenance workers iock out the machine from its power sources beiore beginning repairs?

are multiole lockout devices used?
8, are multiple lockout devices used?

Where several maintenance persons work on the same ma:
Where several maintenance persons work on the same ma

c s@ appropriate and safe equipment in their repair work?

{s the maintenance equipment itself properly guarded?

Are maintenance and servicing workers trained in the requirements of 29 CFR 1910.147,
lockout/tagout hazard, and do the procedures for lockout/tagout exist before they attempt their tasks?

81

<<
¥
a

| |

||
| |

FLT tl
blttl

|


Adjustable guard on bandsaw

Figure 26.



Concepts and Techniques
of Machine Safeguarding

U.S. Department of Labor
Lynn Martin. Secretary

Occupational Safety and Health Administration
Dorothy L. Strunk, Acting Assistant Secretary

OSHA 3067
1992 (Revised)

For sale hy the US. Government Printing Ottice
durenatenuent of Oucuments, Mail Sigs SSOP, Washington, DC 20902.9528

ISBN 0-16-037972-5



Figure 51 shows a chute feed. It may be either a horizontal or an inclined
chute into which each piece is placed by hand. Using a chute feed on an
helps center the piece as it slides into the die, but

inclined pr

may also
may also si

sobiem of
7

‘abiem of ejection.

A plunger feed is shown in Figure 52. The blanks or pieces =
nest one at a time by the plunger which pushes them under the slide.
Plunger feeds are useful for operations on irregularly shaped workpieces
which wilt not stack in a magazine or will nat slide easily down a gravity
chute. The mechanism shown is mechanically connected to the press

achanis: bene te ot ae:

tripping Mechanism. When the plunger is pushed in, pin “B” is aliowed to rise
up into hole “A,” allowing yoke “C” to release so the press can be tripped.

PLUNGER

£8 PRET
pe _~

TRIPROD

Figure 51.
Power press with chute feed

Figure 52.

Power press with piunger feed


30

Figure 35.
Electromechanical
sensing device on an eyeletter


Method

Photoelectric

Radiofrequency
(optical)

Electromechanical

Safeguarding Action

Machine wii not start cycling
is

interrupted

When the light field is broken
by any part of the operator's
body during the cycling

process, immediate machine

braking 1s activated

Machine cycling will not start
when the capacitance field is
interrupted

en the capacitance fieid is
disturbed by any part of the
Operator's body dunng the
cycling process, immediate

is activated

machine drakir

Contact bar or probe travels
a predetermined distance

between the operator and the
between the operator and the

danger area.

Interruption of this movement
prevents the starting of
machine cycie.

As the machine begins to
cycle, the operator's hands
are pulled out of the danger
area
Prevents the operator from
reaching into the danger area

39

Advantages

Can allow freer movement

Used by multiple operators

Provide passerby protection

i

Can allow freer movement
for operator

Can allow access at the point

of operation

Eliminates the need tor
auxiliary barriers or other
interference at the
danger area

VTM yet
Vv

Limitations

Does not protect against
ical fai

Limited to machines that can
be stopped

Does not protect against
mechanical failure

Antennae sensitivity must be
properiy adjusied: this
adjustment must be
maintained properly

Limited to machines that can
be stopped

Contact bar or probe must be
properly adjusted for each

application;
application;

must be maintained properly

Limits movement of operator
May obstruct work space

ist be made
for specific operations and
for each individual

Requires frequent
inspections and regular

Requires close supervision of
Requires close supervision of

the operator's use of
the equipment

Limits movement 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



circular saw

Self-adjusting guard on


and can interfere with communications. thus dering the worker's safe job
performance. Research has linked noise to a whole range of harmful health
effects, from hearing foss and aural pain to nausea, fatigue, reduced muscle
controi, and emotional disturbance. Engineering controis such as the use of
sound-dampening maieriais, and personal protective equipment, such as
ear plugs and muffs, can help contro! the harmful effects of noise. Also,

administrative controls that involve removing the worker from the noise

source can be an effective measure when feasible.

Because some machines require the use of cutting fluids, coolants, and
other potentially harmful substances, operators, maintenance workers, and

others in the lity May need protection. These substances can cause
ailments ran:

ailments ranging from dermatitis to serious illnesses and disease. Specially

constructed safeguards, ventilation, and protective equipment and clothing
are possible temporary solutions to the problem of machinery-related
chemical hazards until these hazards can be better controlled or eliminated

from the workpiace.

Training

Even the most elaborate safeguarding system cannot offer effective
protection unless the worker knows how to use it and why. Specific and
datailed training is therefore a crucial part of any effort to provide
safeguarding against machine-related hazards. Thorough operator training

should i
should in

nq or hands-on training in the followin:
im or hands-on training in the following:

(1) a description and identification of the hazards associated with
particular machines;

(5) what to do (e.g., contact the supervisor) if a safeguard is damaged,
missing, or unabie to provide adequate protection.

This kind of safety training is necessary for new operators and maintenance
or setup personnel, when any new or altered safeguards are put in service,
or when workers are assigned to a new machine or operation.


Figure 69.
Lockout hasp

other serious injuries to the machine operator, the maintenance worker, or

others operating adjacent machines controiled by the same circuit. For this

reason, when maintenance personne! must repair electrically powered

ip . the P

and the department involved. When more than one worker is to be engaged

in the servicing/maintenance function a typical lockout hasp to which each

may affix a personal lock is shown in Figure 69.
Figure 70.

_ Safety blocks installed on
— power press
{i

SAFETY BLOCK



Worker Rights and
Responsibilities

If you are a worker, you have the right to:

* request an OSHA inspection for workplace hazards, violations of
OSHA standards, or violations of the OSH Act (your name will be kept
confidential on request);

* have an authorized employee representative accompany the OSHA
compliance officer on the workplace inspection;

* confer informally with the OSHA compliance officer (in private,
if preferred);

* be notified by your employer of any citations issued for alleged
violations of standards at the workplace, and of your employer's
requests for variances or for changes in the abatement period;

* contest the abatement time set in any citation issued to your employer
by OSHA;

* file a complaint with OSHA if you believe that you have been
dismissed, demoted, or otherwise discriminated against for exercising
rights under OSHA;

* file a complaint with Federal OSHA authorities if your State agency
fails to administer a State program as effectively as required
by OSHA;

* ask OSHA about any tests performed in your workplace, the results of
inspections, and any decision not to take action on a complaint;

* receive information from your employer about hazards and safety
measures applicable to the workplace, OSHA standards relevant to
your job, and the record of accidents and illnesses in the workplace;

* ask that National Institute for Occupational Safety and Health evaluate
and provide information on the substances used in your workplace;

refuse to work in an imminent danger situation, under
certain conditions;

* submit written information or comment to OSHA on the issuance,
revocation, or modification of an OSHA standard and to request a
public hearing; and

* observe the monitoring and measuring of toxic substances in the
workplace if you are exposed, and to have access to any records of
your exposure.

You also have the responsibility to:
* read the OSHA poster in the workplace;

* comply with all the OSHA standards, with all requirements of your
State-approved plan (if any), and with the employer's safety and
health rules;


Figure 53.
Power press with plunger
and magazine feed

Figure 54.

STOCK BEG MOVED
NTS DIE,
\

INTERLOCK 8

Figure 53 shows a plunger and magazine feed. Slot “A” must be in
alignment with interiock “8” before the press can be inpped.

9

The sliding in Figure 54 is pu! fe ig
and then pushed into position under the slide prior to the downward stroke.
The die moves in and out by hand or by a foot lever. The die should be
interiocked with the press to prevent tripping when the die is out of alignment
with the slide. Providing “stops” will prevent the die from being inadvertently

pulied out of the siides.

OIE SUDE

47


Figure 56.
Power press wiih

double-dial fsed
doubie-dial feed

Figure 57.
Shuttle ejection mechanism

As shown in Figure 57, the pan shuttle mechanism moves under the finished
part as the slide moves toward the “up” position. The shuttle then catches
tne part stripped from the siide by the knockout pins and defiects it into a
chute. When the ram moves down toward the next blank, the pan shuttle
moves away from the die area.

SLIDE IN Sune IN
uP ‘OWN
| Position = | POSITION Ea
POINT-OF— 4 ' \
OPERATION | tT \
GUARO : | \

f 4 i tN
ee COMPLETED ~~ \\
SHUTTLE - Le oh PART t >

stock Sy Sy . J I
2 SS law
Ail | SS,
~/t | f=
ft \
CHUTE
—~_

FEEDING L
TOC.


E. Robot
§. Miscellaneous Aids
A. Awareness barriers
8. Miscellaneous protective shieids
C. Hand-teeding tools and hoiding fixtures

Guards are barriers which prevent access to danger areas. There are four
general types of guards:

guard is a permanent part of the
m fis to perform its intended
se cloth. bars

ire Clown, Bars,

m:
plastic, or any other material that is substantial enough to withstand
whatever impact it may receive and to endure prolonged use. This guard is
usually preferable to ail other types because of its reiative simpiicity

Examples of fixed guards...

In Figure 11, a fixed guard on a power press completely encioses the point of
operation. The stock is fed through the side of the guard into the die
with the scrap stock exiting on the opposite side.

<—S = \
S|

\ \ \ STOCK ENTERING
@lg'| | <a ee
NG} |
Ia | .

\, ee TRANSPARENT INSERT
‘\ | \ IN FRONT PANEL,
—7 )
Ne