Mis003

08/06/15
IIMSHE 1
MIS-003 PGDM 1st
semester
MACHINES & MACHINE GUARDS

08/06/15
IIMSHE 2
MIS-003 PGDM 1st
semester
WELCOME
TO
IIMSHE

08/06/15
IIMSHE 3
MIS-003 PGDM 1st
semester
Introduction
 Mostly all the industries use innumerable
machines & these machines, no doubt, help a
fast rate of production & at the same time
reduces the human efforts required for
producing but they are also responsible for a
large number of accidents at work, which are
usually & potentially more severe and some
times very serious but are almost preventable
in the context of hazards involved there in.

08/06/15
IIMSHE 4
MIS-003 PGDM 1st
semester
 Depending upon the way the harm is
caused due to these accidents from
machines can be classified into following
groups:-
 Contact
 Impact
 Traps
 Ejection of Particles
 Electrical or Mechanical Failure

08/06/15
IIMSHE 5
MIS-003 PGDM 1st
semester
 Contact:
Physical contact of body with
moving parts of the machine.
Generally these lead to cuts and
abrasion. e.g. hand touching a V-
belt.

08/06/15
IIMSHE 6
MIS-003 PGDM 1st
semester
 Impact:
Parts of the body being violently hit
by moving parts of machines. e.g.
hit by the ram of a press or hit by
the bed of a planer while travelling.

08/06/15
IIMSHE 7
MIS-003 PGDM 1st
semester
 Traps:
A part of body comes in between
moving parts. This mostly lead to a
crushing of the parts of body
trapped. e.g. hand crushed in
between the die & punch in a power
press or between two rollers.

08/06/15
IIMSHE 8
MIS-003 PGDM 1st
semester
 Ejection of Particles:
Components or parts projected at
high velocity from the machine.
They cause serious injury when they
hit the parts of human body. e.g. a
spanner falling on a coupling is
projected up and hits a worker or
chips flying from machine lands in
the eye of the operator.

MIS-003 PGDM 1st
semester
 Electrical or
Mechanical
Failure:
Electrical or
mechanical failure
which results in a
shock or injury to
worker – say belt
breaking or pulley
coming out while
in motion.
Some of the “hazards” remain with
the machine and the job situation
on a continuing basis and the
operator is exposed to chances of
an accident through out the
operating time. Like operation of a
power press without guard,
machining of brass without eye
protection and working near
unguarded rollers are illustrative
examples. Different from these are
the occasional or contingent
dangers arising out of machine
failures, abnormal work situations
or unexpected human errors. One
should look into the such issues
and identify both the continuing
dangers associated with machine
operation and contingent dangers
that can be predicted.
08/06/15
IIMSHE 9

08/06/15
IIMSHE 10
MIS-003 PGDM 1st
semester
Legal Requirements
 As per the Factories Act, the primary
legislative requirements in respect of
machine guarding are:

08/06/15
IIMSHE 11
MIS-003 PGDM 1st
semester
 Every flywheel and every moving part of
any prime mover shall be securely
fenced.

08/06/15
IIMSHE 12
MIS-003 PGDM 1st
semester
 Every part of the transmission machinery
shall be securely fenced unless it is in
such a position or of such construction as
to be safe to every person employed in
the premises.

08/06/15
IIMSHE 13
MIS-003 PGDM 1st
semester
 Every dangerous part of any machine,
shall be securely fenced unless it is in
such a position or of such construction as
to be safe to every person employed in
the premises otherwise.

MIS-003 PGDM 1st
semester
Secure fencing in this context
can be interpreted as the use
of proper guarding of the
machines from the identified
“hazards” and predicted
dangers of causing accidents to
be provided with the maximum
degree of safety.
In addition to such
requirements set out in the
Factories Act there are various
regulations applying to specific
machines, or unfenced
machinery for example:
 The Woodworking
Machines Regulations.
 The Abrasive Wheels
Regulations.
More over requirements are
placed in respect of the dangers
present while cleaning the
machinery and for the training
and supervision of young
persons working on dangerous
machineries or performing
dangerous operations.
The requirements of the
Health & Safety at Work and
the Factories Act. also must
be borne in mind when
considering machinery safety.
08/06/15
IIMSHE 14

08/06/15
IIMSHE 15
MIS-003 PGDM 1st
semester
Machine Guarding
 Machine Guarding is a term given to
erecting a barrier or a system in between
the operator and the machine with a view to
protect him from specific dangers.
If the functions of the machine and the
guard are understood by the designer, if the
right guard is selected, and if it is installed
correctly, protection of the operator can be
ensured within the reasonable costs.

08/06/15
IIMSHE 16
MIS-003 PGDM 1st
semester
Functional Requirements
Of A Guard
 The guard should offer positive protection to
the operator under all normal working
conditions.
 It should offer protection to others nearby. A
guard protects the operator in front but
presents a danger to the operator of the
nearby machine at the back cannot be
considered acceptable.

08/06/15
IIMSHE 17
MIS-003 PGDM 1st
semester
 The guard should not cause any danger by
itself. One which shakes or rattles, one
which annoys the operator or one which
brings a fresh safety problem (like a pedal
guard which extends to the gang-way) are
also unacceptable.
 The guard should not interfere with normal
operator movements, or functions like oiling
adjusting etc.
 The construction of the guard should be
rigid and sturdy and should be recognized
as an integral part of the machine.

08/06/15
IIMSHE 18
MIS-003 PGDM 1st
semester
Important Aspects
 In making machine operations safe, there
are two distinct aspects which need
consideration of following two factors:

08/06/15
IIMSHE 19
MIS-003 PGDM 1st
semester
 The Safety offered by machine itself:
In terms of type of operation, exposed
dangerous parts, accessibility of
dangerous parts, probability of accident
during normal operations, extent of
severity in case of accident and the
demands made on the operator for safe
performance.
 The operator himself: His knowledge,
skill, understanding of danger, emotional
status and performance.

08/06/15
IIMSHE 20
MIS-003 PGDM 1st
semester
Any attempt to make machine operations safe,
one should consider these above mentioned
both the aspects together – one in relation to
other. Ideally, this work should begin at the
design stage of the machine itself but this is not
the practice always followed and the bulk of
safe-guards and safety features are very often
incorporated after the machine is built and in
some cases, after it has been in use for a long
time (or number of accidents have occurred).
The safe-guards thus incorporated later on, fail
in majority of cases – partly due to their incorrect
design and not being compatible with the
machine functions and partly due to there
unacceptability by the operators.

08/06/15
IIMSHE 21
MIS-003 PGDM 1st
semester
 To make the machine operations safe a
realistic study of the risk involved and the
possible ways in which accidents can take
place is most important feature, and thus in
turn, calls for looking into a number of
interrelated issues like:
Risk Involved

08/06/15
IIMSHE 22
MIS-003 PGDM 1st
semester
 The type of machine, the type of job
handled by the machine, the functions
performed by the machine and the
limitations of the operations.
 The ways in which the machine operation
can lead to injuries to persons, location of
dangerous parts, there speeds, energy
involved etc.

08/06/15
IIMSHE 23
MIS-003 PGDM 1st
semester
 The severity expected in case of an
accident taking place.
 A situation which can cause serious or
fatal injury gets priority over one which
leads to a nick.

08/06/15
IIMSHE 24
MIS-003 PGDM 1st
semester
 The operator position & his movements. Is
it necessary for him to reach dangerous
parts? How often? Can he reach them even
if it is not required as a part of his job? How
easy or difficult it is for him to do so? How
the danger is known? How obvious is it to
the operator, to the supervisor, and to the
layman?
 What are the uncommon situations the
machine is likely to encounter? Defective
material? Careless operators? Operator on
incentive? Rush work? Is the risk enhanced
under such conditions? To what extent?

08/06/15
IIMSHE 25
MIS-003 PGDM 1st
semester
 What are the extra demands put on the
operator for safe performance of
machine? More skill? More alertness?
More care? Physical strength? To what
extent, the operator meets the demands?
 Can the job be made absolutely safe? If
not, to what extent it can be done? What
are the limiting factors? Can they not be
overcome?

08/06/15
IIMSHE 26
MIS-003 PGDM 1st
semester
 What are the different choices of safe-
guards available? What degree of
protection each gives? At what cost?
 Identify all possible chances of accidents
including human errors and neglects.

08/06/15
IIMSHE 27
MIS-003 PGDM 1st
semester
 Reduce the reliance on human element in
operational safety to the minimum by
increasing the reliability of the machine.
 Safeguard against human errors including
neglect and willful misuse (like removing
machine guards). The observation by Dr.
Richard Booth that the “unpredictable
human behaviour should represent a
challenge to the design skill of engineer
and should not be smoke screen to
misrepresent a careless or untidy design”
is more than correct.

08/06/15
IIMSHE 28
MIS-003 PGDM 1st
semester
 Identify weak elements in the design itself
(if any) and compensate them by
specifying procedural safeguards,
warning devices or supervisory action.
 Consider the operator in all aspects.

08/06/15
IIMSHE 29
MIS-003 PGDM 1st
semester
 To make the machine safe by its design itself,
such that they do not offer any scope for
accident should be the first choice in ensuring
safety in the machine operations. This work
begins at the designer’s table. Apart from the
machine functions and operations, the operator
and his performance and the work situations
should be studied & the safeguards
incorporated in the design/operation of the
machine should be such that operators are
never exposed to danger. Incorporating
safeguards in the design stage itself has many
advantages like:
Design Criteria

08/06/15
IIMSHE 30
MIS-003 PGDM 1st
semester
 Design of safeguards are done by the
same professional who designed the
machine.
 The question of functional incompatibility
between machine operation and
safeguards does not arise.

08/06/15
IIMSHE 31
MIS-003 PGDM 1st
semester
 They work out cheaper compared to the
safeguards incorporated later on.
 Since the safeguards arrive as a part of
the machine, they have a greater level of
acceptability from operators.

08/06/15
IIMSHE 32
MIS-003 PGDM 1st
semester
 Since safety standards can not be drawn
which will cover every conceivable
hazardous mechanical exposure, it is often
necessary to use imagination and ingenuity
to protect usual situations. If the basic
hazardous actions and motions are
understood, it is easier to evaluate the
hazard and to develop effective control
measures, what ever is the machine,
involved with the type of action or motion
there in.

08/06/15
IIMSHE 33
MIS-003 PGDM 1st
semester
 While doing the assessment of risk
presented by a machine during every phase
of its operation, the likely and forcible human
behaviour must also be considered because
the greater the risk from the machine and the
more likely the possibility of abrupt human
behaviour demanding the greater degree
and as well as need to take every possible
step in ensuring the safety by taking the
following two factors into account while
assessing the risk:
a) The severity of forcible injuries; and
b) The probability of there occurrence.

08/06/15
IIMSHE 34
MIS-003 PGDM 1st
semester
 The greater the possibility of injury or
occurrence the greater the need to protect
against it, and thus the greater should be
the reliability of protection with the greater
degree of safety.

08/06/15
IIMSHE 35
MIS-003 PGDM 1st
semester
 In any machine system where its safety may
be adversely affected by the failure of any
single part, or the whole, than each
component in the system must be
considered in ordered to determine the
probable potential of its failure modes and
the consequences due to its failure.

08/06/15
IIMSHE 36
MIS-003 PGDM 1st
semester
 Safeguards built into a machinery should be
designed and constructed in such a way
that bypassing or defeating them either
accidentally or deliberately is made
impossible or difficult as possible.

08/06/15
IIMSHE 37
MIS-003 PGDM 1st
semester
 While doing the maintenance or modification
of any machinery or system, it should be
intended to preserve the design level of
safety performance and where ever
practicable these activities should intend to
improve the overall safety performance.

08/06/15
IIMSHE 38
MIS-003 PGDM 1st
semester
 Plant layout & house keeping also play an
important & crucial role in providing the good
machine guarding for safe operations and
safe working conditions, as making the
machines safe alone is of little use unless the
entire work area around the machine is also
made safe like few conditions to mention
below: e.g.
Role of Plant
Layout & House
Keeping

08/06/15
IIMSHE 39
MIS-003 PGDM 1st
semester
.
 A properly guarded power press installed
in a confined space with tools, dies, sheets
and scrap scattered around can not be
considered safe.
 A correct lay out which permits adequate
area for the free movement of the
operator, sufficient space for material
before and after processing and provision
for collection and disposal of scrap are
also essential for ensuring the safe
operations.

08/06/15
IIMSHE 40
MIS-003 PGDM 1st
semester
 The relative position of the machine with
respect to aisles and traffic, movement of
material, welding and other jobs near by
(which can obstruct the operator) are
important considerations and need to be
looked into.
 General cleanliness, orderliness and
house keeping around machine are no
less important aspects.

08/06/15
IIMSHE 41
MIS-003 PGDM 1st
semester
 Never the less the another unsaid area is of
machine maintenance, which has an
indirect but definite relation with safety
performance of machines and machine
guarding. There are three ways in which
safety and maintenance are linked.
Silent Feature of
Maintenance &
Machine Guarding

08/06/15
IIMSHE 42
MIS-003 PGDM 1st
semester
1. Accidents due to failure to maintain:
Failure to maintain machines in good working
order can and does lead to sever accidents.
Most of the accidents resulting from machine
failure – electrical, mechanical, hydraulic etc.-
can be traced to poor machine maintenance.
A jammed bearing making a shaft break, a
worn out key causing a double stroke in a
power press or a faulty switch short circuiting
the interlock system are common causes of
accidents, if system of preventive
maintenance is poor and one should take
following care in this regard.

08/06/15
IIMSHE 43
MIS-003 PGDM 1st
semester
 Provide routine care to all
components.
 Regular inspection and checking of all
machines and its components.
 Timely identification and replacement
of defective components.
 Periodic lubrication as per standards.
 Arrangements to bring any deviations,
failure, or abnormal behaviour to the
notice of persons who can initiate
corrective action.

08/06/15
IIMSHE 44
MIS-003 PGDM 1st
semester
2. Accidents due to incorrect
maintenance: Examples.
 The machine is overhauled, but
the guard is not replaced.
 An electric motor is replaced,
but the earth connection is
forgotten.
 Incorrect assembly, adjustments
or settings.
 Poor or defective workmanship.

08/06/15
IIMSHE 45
MIS-003 PGDM 1st
semester
The possible remedies for these lie
in :-
a)Training of the maintenance crew.
b)Installing procedure for strict
quality control in maintenance
work. (Stages of inspection are
introduced to make sure the work
is going on as per specifications &
standards.)
c) Batter quality of supervision.

08/06/15
IIMSHE 46
MIS-003 PGDM 1st
semester
3. Accidents during maintenance:
Maintenance and repair work have character
different from routine production work. Firstly, the work
is not repetitive in nature and the problems
encountered are not the same always. Workman have
to take inconvenient and dangerous postures due to
the exigencies of the job. There is an element of
“RUSH” in majority of jobs, which encourages short-
cuts and indifference to safety requisites. Further, the
equipment under maintenance itself is far less reliable
than one in good working order and normally, the
safety features are absent during maintenance. These
conditions offer increased chances of accidents during
maintenance/repair work and the typical examples are:

08/06/15
IIMSHE 47
MIS-003 PGDM 1st
semester
o Accidental descant of a ram in a
power press during repairs.
o Accidental starting of machines
or sudden movement of
components.
o Sudden release of energy as in
the case of rebounding of
springs.
o Accidents while
removing/replacing heavy
components in difficult
positions.

08/06/15
IIMSHE 48
MIS-003 PGDM 1st
semester
The solution to the problems lies in
recognising the increased hazards in
maintenance and taking additional
safety measures and the following
elements should be the part of any
maintenance programme:-

08/06/15
IIMSHE 49
MIS-003 PGDM 1st
semester
 Advanced planning, job safety
analysis and establishing safe work
methods.
 Training of maintenance crew.
 Good quality of supervision.

08/06/15
IIMSHE 50
MIS-003 PGDM 1st
semester
Once these issues are studied, the broad
requirements of safeguards surface, and considering
the operation, cost of safeguarding and convenience,
a decision can be taken regarding the protection to
be chosen.
Basically the approach should be to make the
machine itself intrinsically safe without relying on the
operator.
When this is not practically possible, the machine
should be made safe to the extent possible and any
deficiency existing should be compensated by
improving the reliability of the operator and his
performance.

08/06/15
IIMSHE 51
MIS-003 PGDM 1st
semester
Principles Of
Guarding
 All the mechanical action or motion of any
type of machine are hazardous, but in
varying degrees. These movements of
machinery having parts like rotating
members, reciprocating arms, moving belts,
meshing gears, cutting teeth etc. requires the
necessary protection which one or the other
way turns into the some form of impact,
shearing/cutting or bending action with the
following type of motions or the situation:

08/06/15
IIMSHE 52
MIS-003 PGDM 1st
semester
 Rotary;
 Sliding or Reciprocating; or
 A combination of both the above;
 Transverse motions;
 In running Nip Points.

08/06/15
IIMSHE 53
MIS-003 PGDM 1st
semester
Hazardous actions &
motions in machines

08/06/15
IIMSHE 54
MIS-003 PGDM 1st
semester

08/06/15
IIMSHE 55
MIS-003 PGDM 1st
semester

08/06/15
IIMSHE 56
MIS-003 PGDM 1st
semester

08/06/15
IIMSHE 57
MIS-003 PGDM 1st
semester

08/06/15
IIMSHE 58
MIS-003 PGDM 1st
semester

08/06/15
IIMSHE 59
MIS-003 PGDM 1st
semester

08/06/15
IIMSHE 60
MIS-003 PGDM 1st
semester

08/06/15
IIMSHE 61
MIS-003 PGDM 1st
semester

08/06/15
IIMSHE 62
MIS-003 PGDM 1st
semester

08/06/15
IIMSHE 63
MIS-003 PGDM 1st
semester

08/06/15
IIMSHE 64
MIS-003 PGDM 1st
semester

08/06/15
IIMSHE 65
MIS-003 PGDM 1st
semester

08/06/15
IIMSHE 66
MIS-003 PGDM 1st
semester

08/06/15
IIMSHE 67
MIS-003 PGDM 1st
semester

08/06/15
IIMSHE 68
MIS-003 PGDM 1st
semester

08/06/15
IIMSHE 69
MIS-003 PGDM 1st
semester

08/06/15
IIMSHE 70
MIS-003 PGDM 1st
semester

08/06/15
IIMSHE 71
MIS-003 PGDM 1st
semester

08/06/15
IIMSHE 72
MIS-003 PGDM 1st
semester

08/06/15
IIMSHE 73
MIS-003 PGDM 1st
semester
Types Of Guarding
 Depending upon the principles of operation
guards can be classified into the following
four main types of guarding:
1. Fixed Guards
2. Interlock Guards
3. Automatic Guards
4. Trip Guards or Other safe-guards.

08/06/15
IIMSHE 74
MIS-003 PGDM 1st
semester
1.FIXED GUARDS:
This has no moving parts and is a barrier
between the dangerous part and the man
which is fixed to the machine and remains
permanently fixed by preventing access to
the dangerous parts of the machine to man.
A cycle chain cover or a grill in front of a fan
are the examples of fixed guards. Other
examples are fixed covers for gears,
enclosures for fly wheels and common
guards for belt derives. These Fixed Guards
can be further sub classified as:

08/06/15
IIMSHE 75
MIS-003 PGDM 1st
semester
 Enclosing guards: Prevents access to
danger points by enclosure.
 Distance guards: Does not completely
enclose a hazard but reduces access by
virtue of its physical dimensions and
distance from the hazard.
 Adjustable guards: Fixed guards
incorporating an adjustable element to
allow for different operations or materials
to be used in the same machine.

08/06/15
IIMSHE 76
MIS-003 PGDM 1st
semester
 Self adjusting guards: A fixed or movable
guard which adjusts itself to allow the
passage of material and is actuated by
the passage of the workplace or material
at the start of the operation and returning
to the safe position on completion.

08/06/15
IIMSHE 77
MIS-003 PGDM 1st
semester
 False Table: Can be used to overcome
the problems presented by power
operated feed tables, and which has the
effect of filling the space between the
workplaces on rotary or traversing feed
tables, and thereby blanking off openings
in guards while the machine is in
operation.

08/06/15
IIMSHE 78
MIS-003 PGDM 1st
semester

08/06/15
IIMSHE 79
MIS-003 PGDM 1st
semester

08/06/15
IIMSHE 80
MIS-003 PGDM 1st
semester

08/06/15
IIMSHE 81
MIS-003 PGDM 1st
semester

08/06/15
IIMSHE 82
MIS-003 PGDM 1st
semester
 The main advantage the fixed guard has
over the other types of guards is that it is
comparatively simpler in design and use,
robust in construction and if it can be
opened or removed it would be possible
only with the aid of special tool and it is not
possible for operator or any one to simply
remove such guards.
Advantages of
Fixed Guards

08/06/15
IIMSHE 83
MIS-003 PGDM 1st
semester
 Fixed guard is ideal choice when the parts to be
guarded are not required to be approached often in
the course of work but are not suitable where the
moving parts are to be approached every now and
then, for example, in case of a V-Belt derive where
the belts have to be changed frequently for speed-
changing, the chances are that the operator will
keep the guard removed (Partly adjustable, folding
or sliding arrangements can be incorporated in
fixed guards for such arrangements provided it can
be ensured (by means of interlocking or increased
operator reliability) that the guard is in its position
after every adjustment and the machine is stopped
when the adjustment is carried out.

08/06/15
IIMSHE 84
MIS-003 PGDM 1st
semester
 They seldom need routine adjustments, and
as a result causes less maintenance
problem and costs less.

08/06/15
IIMSHE 85
MIS-003 PGDM 1st
semester
.
 A fixed guard provides the highest degree of
protection against danger/hazards and
should always be the first choice of guard
where ever possible.

08/06/15
IIMSHE 86
MIS-003 PGDM 1st
semester
2. INTERLOCK GUARDS:
When a fixed enclosure guard is not practicable, an
interlocking enclosure or barrier should be considered
as a first alternative. When the fixed guard can not be
used in situation where the moving parts have to be
approached frequently, as in case of lift door in which
people have to go in and out, or power press in which
the operator has to put in his hand to feed the job and
take out an interlock guard may be the ultimate choice
with a device or system which links the function of the
operator and the machine in such a way that (a) the
parts are not accessible when the danger is present
(b) when the parts are accessible, the danger is not
present and that can be achieved by mechanical,
electrical, hydraulic or electronic systems.

08/06/15
IIMSHE 87
MIS-003 PGDM 1st
semester
 An interlocking enclosure guard is not
fixed and may be opened or removed as
the operator requires. However due to an
electrical or mechanical interlocking
connection with the operating
mechanism, the operation of the machine
is prevented until the guard is returned to
an operating position and the operator
can no longer reach the point of danger.
An interlocking guard should do three
things:

08/06/15
IIMSHE 88
MIS-003 PGDM 1st
semester
a. Shut off or disengage the power to
prevent the starting of the machine
when the guard is open.
b. Guard the danger point before the
machine can be operated.
c. Keep the guard closed until the
dangerous part is at rest, or stop the
machine when the guard is open.

08/06/15
IIMSHE 89
MIS-003 PGDM 1st
semester
 Interlock systems are effective, only if they
are correctly designed, installed and
adjusted. They also need to be periodically
inspected, checked, adjusted and
maintained in good shape & condition. A
loose nut in the interlock for the stroke
mechanism, a defective contact in a switch
or the wrong adjustment of a cam can
easily defeat the purpose of the interlock
guard.
.
Limitation of
Interlocking

08/06/15
IIMSHE 90
MIS-003 PGDM 1st
semester
 Some examples of interlock systems are:
o Operation of the passenger lift is
electrically so controlled that the lift
does not move when the doors are open
and that the doors cannot be opened
when the lift is moving.
o In power press a guard provided in front
of the dangerous zone is so linked with
the stroke mechanism that with the
guard off, the stroke can not be
released by the pedal (or hand).

08/06/15
IIMSHE 91
MIS-003 PGDM 1st
semester
o Cam activated switches which puts off the
supply in case doors leading to dangerous
parts are opened.
o Two hand control devices in which both the
hands of the operator are required to be busy
during operation-For example he has to press
two buttons simultaneously with both hands
to activate stroke in hydraulic presses.
o Trapped key systems in which dangerous
parts have to be securely locked in to release
the key required to switch on the machine.
Without proper locking in, the key for
machine operation remains trapped in its key
hole.

08/06/15
IIMSHE 92
MIS-003 PGDM 1st
semester
 Some other forms of interlock
systems are:
o Control guards:
The action of closing the guard
initiates the operation of the
machinery.
The machine can not start until
the guard is closed, and
The guard remains locked
closed during any dangerous
motion.

08/06/15
IIMSHE 93
MIS-003 PGDM 1st
semester
o Enclosure guards:
Prevent access to danger points
by enclosure.
o Distance guards:
Does not completely enclose a
hazard but by virtue of its dimensions
and its distance from the hazard
reduces access.

08/06/15
IIMSHE 94
MIS-003 PGDM 1st
semester
 In addition, rotation or motion sensing
devices which are interlocked with
machine derive mechanisms or power
supplies may be used.
 It should be appreciated that the overall
aim of any interlocking guard system
should be to minimize the possibility of the
whole system “Falling into danger”
 Specific application of
Interlocking

08/06/15
IIMSHE 95
MIS-003 PGDM 1st
semester

08/06/15
IIMSHE 96
MIS-003 PGDM 1st
semester

08/06/15
IIMSHE 97
MIS-003 PGDM 1st
semester

08/06/15
IIMSHE 98
MIS-003 PGDM 1st
semester

08/06/15
IIMSHE 99
MIS-003 PGDM 1st
semester
3. AUTOMATIC GUARDS:
When neither an enclosure guard nor an interlocking guard is
practicable, an automatic guard may be used. Where in the
interlock guard an action by the operator is necessary to
activate the protection mechanism, the automatic guard is one
which functions independently of the operator by repeating its
cycle as long as the machine is in motion. As these guards are
moved into position automatically being operated by the
machine itself through a system of linkages connected to the
operating system and remove any part like hands, arms or
body of a person from the danger zone as the ram, plunger or
other tool closes on the piece upon which work is being done.
The essential requirement of such guards is that they do not
create a hazard in themselves in their operation. These guards
are comparatively costlier & demands very good maintenance
standards, periodic adjustments and frequent checking.
.

08/06/15
IIMSHE 100
MIS-003 PGDM 1st
semester
 Common type of automatic guards are
sweep and push-away devices which are
moving barriers crossing the danger zone
when the machine is activated, and pull-
away devices consisting of and arm
attachments which pulls the operator away
from the danger zone. These devices
should be designed to prevent the operator
from reaching behind or across the
protective device into the danger zone
before the machine has completed its
closing cycle.

08/06/15
IIMSHE 101
MIS-003 PGDM 1st
semester
 The guard must be securely fixed to the
machine so that it cannot be adjusted or
detached without the aid of tools; and
should be actuated by the dangerous part
of the machine itself.

08/06/15
IIMSHE 102
MIS-003 PGDM 1st
semester
 The main advantage of such guards is
that they must work in time with the
machine movement, thus they are
generally unsuitable for the fast acting
machines.

08/06/15
IIMSHE 103
MIS-003 PGDM 1st
semester
 The principle of working of such guards can be
understood by following three examples:
 In the “hand pull-out device” in a power press the
operators hand has a strap which is connected
through a series of pulleys to the ram itself. The
strap itself is light and with the ram up the hands
are quite free. The operator can without any trouble
or inconvenience carry out normal work of removing
the finished job, feeding the next one and taking out
the hand before activating the stroke. But, in
process, if he forgets or fails to take out the hand
(as it happens many times) the motion of the ram
coming down simultaneously pulls his hand out.
Principles of Automatic
Guards

08/06/15
IIMSHE 104
MIS-003 PGDM 1st
semester
 Installation of a sweep guards in front the
die in power press in such a way that
when the ram comes down the sweep
traverse, from left to right, (or right to left
or backwards or forward depending on
the need) and removes the hand of the
operator, if it happens to remain in the
danger zone.

08/06/15
IIMSHE 105
MIS-003 PGDM 1st
semester
 Light from electrical bulbs installed in
front of a sheering machine on one side
falls on photo-electric cells installed on
the other side. This light beam acts as a
guard and if it is interrupted by any thing,
including the hands of the operator the
machine (or the process) is brought to a
stop.

08/06/15
IIMSHE 106
MIS-003 PGDM 1st
semester

08/06/15
IIMSHE 107
MIS-003 PGDM 1st
semester

08/06/15
IIMSHE 108
MIS-003 PGDM 1st
semester

08/06/15
IIMSHE 109
MIS-003 PGDM 1st
semester

08/06/15
IIMSHE 110
MIS-003 PGDM 1st
semester

08/06/15
IIMSHE 111
MIS-003 PGDM 1st
semester

08/06/15
IIMSHE 112
MIS-003 PGDM 1st
semester

08/06/15
IIMSHE 113
MIS-003 PGDM 1st
semester

08/06/15
IIMSHE 114
MIS-003 PGDM 1st
semester
4. TRIP GUARDS:
These devices are not guards as such; they
are devices which causes working machinery
to stop/trip or assume a safe position or
condition when a person approaches a
danger point or into the area beyond a safe
limit, they are also required to maintain the
machinery in such a safe condition while a
person remains in the danger area, and such
devices fall into two broad categories:
a. Mechanical trip devices, and
b. Electrical/ electronic devices.

08/06/15
IIMSHE 115
MIS-003 PGDM 1st
semester
 There are other methods also to make
machine operation safe, like:
o Arrangements to reduce/eliminate
human components of work. A typical
example in substituting automatic feed
in place of manual feed. Also
arrangements to have automatic
ejection in power presses eliminates
the need of operator having to put his
hand in the dangerous areas.

08/06/15
IIMSHE 116
MIS-003 PGDM 1st
semester
.
o Use of special tools: Nose-pliers, screw
drivers. Tongs specially designed pliers
etc. can be used to hold the job, feed the
job etc. such that their use eliminates the
need of hands reaching dangerous area.
How ever it has to be ensured that the
tools used is convenient for operation,
and also that the operator does make
use of it.

08/06/15
IIMSHE 117
MIS-003 PGDM 1st
semester
o Warning devices, Indicator lights and
signals can be used to warn the
operator of eminent dangers. e.g. A
red light burns when the guard is in
open position.

08/06/15
IIMSHE 118
MIS-003 PGDM 1st
semester

08/06/15
IIMSHE 119
MIS-003 PGDM 1st
semester
 The common way in which the guards are
misused by the workmen are:
1. Guards removed by the operator or
defeated in many manner for apparent
convenience or faster rate of production
under incentive scheme.
2. Guards removed by maintenance workers
or setter or not put back.
3. Guards not adjusted correctly.
Never to Forget

08/06/15
IIMSHE 120
MIS-003 PGDM 1st
semester
 The problem of misuse of guards is not
confined to workmen alone. One can easily
come across case of wrong selection, wrong
design, wrong installation and wrong use of
guards in industries.

08/06/15 IIMSHE 121
MIS-003 PGDM 1st
semester
Nearby every such machine, a notice indicating
safety aspects be provided, safe working speed
should be mentioned on it. As the Sec.30 of
Factories Act. covers safety precautions in the use
of grinding wheels. It specifies a notice indicating
maximum safe working, peripheral speed of grinding
stones, the speed of shaft or spindle etc. The section
also says that the safe peripheral speed of any
revolving cages, vessel, basket, fly wheel, pulley, disc
or similar appliances driven by power is not
exceeded.
Rotating
Machines

08/06/15 IIMSHE 122
MIS-003 PGDM 1st
semester
Principles of Safety Integration, like any applied science, is based upon
fundamental principles and rules of practice. As such it involves the
identification, evaluation, and control of hazards in man-machine systems
(products, machines, equipment, or facilities) that contain a potential to
cause injury to people or damage to property. Briefly stated, the basic
rules of hazard control involve system design, the use of physical
safeguards, and user training. Further, it must be thoroughly understood
that no safety device equals the elimination of a hazard on the drawing
board, and no safety procedure equals the use of an effective safety
device.
This approach has been advocated by the safety literature and successfully
practiced by safety professionals for decades.
Principles of Safety
Integration

08/06/15 IIMSHE 123
MIS-003 PGDM 1st
semester
 Every activity must be carried out in accordance with a developed Safe Working
Practice.
 •This shall be validated by means of a Risk Assessment.
 •The control measures identified in the risk assessment shall form the basis for
the written Safe Working Practice.
 •The Safe Working Practice shall follow a logical sequence of progression.
 •Consider what must be done before the task starts?
 •How the task is done?
 •What training is needed?
 •What competence is required or certification?
 •The action to be taken when the task is complete.
 •The Safe Working Practice shall be developed by the persons conducting the
task and led by the Responsible Manager or person concerned.
Safe Work
Practice

08/06/15 IIMSHE 124
MIS-003 PGDM 1st
semester
 The Responsible Manager should delegate responsibility.
 Delegation must be confirmed in writing, and the manager must be assured
that the delegate is competent to lead the development process, via internal
training.
 •The Responsible Manager shall review all Safe Working Practices, before
adoption in the workplace.
 •All Safe Working Practices shall be dated and assigned a version number.
 •In orders to track changes and ensure employees are using the latest version.
 •Any changes considered necessary shall be discussed with the persons whom
have developed the Safe Working Practice.
 •Agreement shall be warranted, from all parties, before the practice is adopted.
 •If in doubt, ask!
How do we comply a Safe Work
Practice ?

08/06/15 IIMSHE 125
MIS-003 PGDM 1st
semester
1. Guards are free of sharp edges, protrusion into walkways, etc., that
cause the guard to be a hazard.
2. Where drums or barrels are revolving (tumble blending) to blend
materials, an enclosure with the entrance interlocked with the drive is
present and functions properly.
3. Fans which are less than 7 feet above the floor are guarded with
openings 1/2' or less.
4. Machines designed for a fixed location are securely anchored to prevent
them from walking or moving.
5. Table saws have guards which enclose the blade above the table and
when cutting, the exposed blade above the material being cut.
6. Disk sanding machines have a guard enclosing the revolving disk.
Check List for Machine Guards

08/06/15 IIMSHE 126
MIS-003 PGDM 1st
semester
7. Belt sanding machines have guards at each nip point where
the sanding belt runs into a pulley.
8. Grinding wheels have:
a. Work rests adjusted to within 1/8" of the wheel.
b. A guard over the spindle end, nut and flange
projections.
c. For most grinders, the acceptable unguarded
opening is 65 deg. above the horizontal and 90 deg. total
maximum exposure.
Contd.

08/06/15 IIMSHE 127
MIS-003 PGDM 1st
semester
9. Friction brakes are capable of quickly stopping the
operation of the press and holding the slide in constant
position
10. Foot operated presses:
a. Have pedals protected to prevent accidental activation of
the machine by falling objects or accidentally stepping on the
pedals.
b. Have pads of the pedal with nonslip contact areas.
11. Hand lever operated power presses have a spring latch on
the operating lever.
Contd.

08/06/15 IIMSHE 128
MIS-003 PGDM 1st
semester
12. The operating levers on the hand-tripped presses having
more than one operation are interlocked to prevent the
tripping of the press except by the concurrent use of all
levers.
13. On machines using part revolution clutches in addition to
the above: A red color stop control is used to open the clutch,
apply the brake and stop the machine.
14. The main power disconnect switch on each machine is
capable of being locked only in the main of position.
Contd.

08/06/15 IIMSHE 129
MIS-003 PGDM 1st
semester
15. The motor start button is protected by a guard, cover, etc.,
to prevent accidental operation.
16. Mechanical power presses controls have driven motor
starters that automatically disconnect from the power source
when there is a power failure.
17. Electrical clutch/brake control electrical circuits have
features which will prevent an accidental ground in the
control circuit causing false operation of the press.
Contd.

08/06/15 IIMSHE 130
MIS-003 PGDM 1st
semester
18. All point of operation guards.
a. Prevent entry of hands or fingers into the point of
operation by reaching through, over, under, or around
the guard.
b. Comply with the following table which shows the
distances those guards is positioned with the indicated
opening in the guard.
Distance of Opening from Maximum Width of Opening
(inches) Point of Operation Hazard (inches)
Contd.

08/06/15 IIMSHE 131
MIS-003 PGDM 1st
semester
19. Where power presses are not equipped with point of operation
guards, a point of
a. A device to prevent and/or stop the press if the operator's
hands are inadvertently placed in the point of operation (e.g., light beam
which when broken stops the press or restraints).
b. A device such as cables are connected to the employee's wrists
that prevent the employee from placing his hands in the point of
operation.
c. Two hand controls exist.
20. a. The distance of each control from the point of operation is
appropriate.
b. The hand controls must be mounted so that an operator
cannot easily move them.
Contd.

08/06/15 IIMSHE 132
MIS-003 PGDM 1st
semester
21. Dies to control or eliminate hazards are stamped with the tonnage and
stroke requirements.
22. Die handling equipment with attach points is provided on all dies
requiring mechanical handling.
23. Inspection or presses are done weekly and records are available
covering the inspection of:
a. The condition of the clutch/brake mechanism.
b. Anti-repeat and single stroke mechanisms.
c. All guards are in place.
d. All other safety features of the press are in operating
condition and properly adjusted.
24. Employees are trained in inspecting and maintaining power presses.
Contd.

08/06/15 IIMSHE 133
MIS-003 PGDM 1st
semester
25. For mechanical power-transmission apparatus:
a. Flywheels set 7 feet or less above the floor or
platform are guarded either with an enclosure or guardrail.
The guard must have sufficient strength to control the
flywheel in the event the shaft fails.
b. All crank and connecting rods when exposed to
contact are guarded.
26. A checklist covering the inspection of power transmission
equipment is completed every 60 days and kept in good working
condition at all times.
Contd.

08/06/15 IIMSHE 134
MIS-003 PGDM 1st
semester
Section 2(Ca); Model Rule 2A: defines competent person as
such a person or an institution who has qualifications,
experience and facilities to carry out examinations and
inspections required by the Factories Act and is recognized by
The Chief Inspector of Factories. The competent person
should not be above 62 years of age. Types of qualification,
experience and facilities at command may vary with types of
competency required namely: pressure plants, lifting
machines, suitability & stay ability certificate and ventilation
system etc.
Competent Person

08/06/15 IIMSHE 135
MIS-003 PGDM 1st
semester
Inspection, Testing & due Certification should be carried out and
ensured by the user in physical presence of the competent
person of all these equipment's (like: lifting tools & tackles,
hoists, lifts, cranes), machines, pressure vessels / plants, boilers,
buildings & structures etc. as per the schedule and directives of
the state rules prescribed there in the Factories Act vide various
sections (like: Section 28 to 40, 40A) and The Indian Boiler Act
with due course of interval of time by maintaining its record
along with the compliance of inspection notes / reports for the
purpose.
Inspection, Test and Certification

08/06/15 IIMSHE 136
MIS-003 PGDM 1st
semester
Beside state rules for achieving better performance in the field of
industrial safety any management should encourage its personnel to
follow safety rules & procedures.
The rules framed should be simple and understandable and should
avoid conflicts of opinion.
They should meet the objectives of the company and they may be
changed as and when situations demand.
The management should see that the rules are framed only when
they are essential.
The number of rules should not be too much to create confusions
and frustrations among people.
Safety
Rules

08/06/15 IIMSHE 137
MIS-003 PGDM 1st
semester
MACHINES & MACHINE GUARDSPower Press
Regulations
Power Presses Regulations, 1984
In exercise of the powers conferred by section 3 of the
Factories Ordinance, the Minister of Labour and Social
Services has made the following regulations:-
1. (1) These regulations may be cited as the Power Presses
Regulations, 1984.
(2) These regulations shall come into force after twenty-
one days from the day on which they are laid on the
Table of the House of Representatives in accordance
with the provisions of subsection (3) of section 3 of the
Factories Ordinance, which date shall be notified by the
Minister of Labour and Social Services by notice in the
Gazette.
2. In these regulations, unless the context otherwise
requires -
"approved" means approved by certificate of the
Director of Labour;
"clutch mechanism" means, in relation to a power
press, a device designed to impart when required the
movement of the flywheel to any tool;
"factory" has the same meaning as is assigned to it by
section 2 of the Ordinance insofar as a power press is
installed or used in any such premises;
"fixed fencing" means fencing provided for the tools
of a power press being fencing which has no moving
parts associated with or dependent upon the
mechanism of a power press and includes that part of a
closed tool which acts as a guard;

08/06/15
IIMSHE 138
MIS-003 PGDM 1st
semester
ENSUREENSURE
SAFETYSAFETY

Mis003

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