Workshop safety

The safety in Workshops has been written not only to provide appropriate safety
procedures but also to assist trained workshop personnel with the provision of a
reference document outlining the general principles of safe working practices
relevant to the mechanical engineering aspects. It relates to specific are as where
definite safety measures are required for workshop operations

Factories Act and Accident

Various acts relating to accidents are spelt out in workmen’s compensation Act-
1923, The factories act-1948 and Fatal Accidents Act-1855. These acts describe
the regulations for fencing and guarding the dangerous machinery, items and
employer’s liabilities.

1.1.6 Concept of accident

It is very difficult to give a definition of the word‘Accident’. However, a generally

accepted conception that an accident is a mishap, a disaster that results in some sort
of injury, to men, machines or tools and equipments and in general loss to the
organization.

The said injury or loss may be of minor or major nature and the accident is termed
as non-reportable or reportable. For example, a small cut on the body will be
reportable accident in a training workshop. It can be treated by first aid and does
not involve any appreciable loss of time, and will not be considered a reportable
accident in a production unit.

1.1.7 Causes of accidents

The 98% accidents could be easily avoided provided due precautions are taken
well in time. A very familiar slogan goes on to say that accidents do not just
happen but are caused due to the failure of one element or the other, and the most
unfortunate factor is that the human element is the most pronounced of all which
fail.

The common causes which lead to accidents are the following:

1. Unsafe working position.

2. Improper or defective tools or their improper use.

3. Improper acts- which result in violation of safety rules and non-observance

of safety precautions.

1.1.8 Common sources of accidents

The large number of machines in use and an even larger number of parts. This can
be regarded as sources of danger and require guarding for protection against
accidents.

Some common sources of accident are listed below :

Projecting nips between sets of revolving parts, viz., gears, rolls and friction
wheels, etc.

1. Projecting fasteners on revolving parts.

2. Revolving cutting tools, circular saw blades.

3. Revolving drums, crushers, spiked cylinder and armed mixers, etc.

4. Revolving shafts, spindles, bars and tools like drills,reamers, boring bars
and chucks, etc.

5. Projecting sharp edges or nips of belt and chain drives viz., belt, pulleys,
chains, sprockets and belt fasteners.

6. Reciprocating tools and dies of power presses, drop hammers, and

revolving presses, etc.

7. Grinding wheels and stones.

8. Reciprocating knives and saw blades such as cutting and trimming

machines and power hack-saws, etc.

9. Revolving drums and cylinders without casing, such as concrete and other
mixers.

10. Intermittent feed mechanisms.

11. Projecting nips between various links and mechanisms, like cranks
connecting rods, piston rods, rotating wheels and discs, etc.

1.2. Common Methods of Protection

The common methods of protection against accidents are the following:

1. Safety by position.

2. Safety by construction.

3. Safety by using interlock guards.

4. Safety by using fixed guards.

 5. Safety by using automatic guards.

6. Safety by using distance guards.

1.2.1 Safety by construction

When a new machine is designed, it should be ensured that all its dangerous parts
are either enclosed in suitable housings or provided with suitable safety guards. For
example, the belt drive and motor in a lathe or milling machine are enclosed, the
back gears in a lathe are either enclosed or provided with cast iron guards or
covers. Lubricating points are provided on the outer surfaces so that the interior
parts are not required to be opened every time.

1.2.2 Safety by position

The machine design is in such a way that the dangerous parts are located such that
they are always beyond the reach of the operator. The dangerous parts of all the
machines should invariably be guarded and undertaking should be made to make
them enclosed in the body or housing of the machines.

1.2.3 Safety by using interlock guards

It is a very efficient and sound method of guarding in that the guard cannot be
removed and dangerous parts exposed until and unless the machine is totally
stopped. Similarly, the machine cannot be started to work unless the guard returns
in position and protects the dangerous parts.

An interlocking guard may be mechanical,electrical or some sort of a combination

of these. It is essential that it should:

1. Prevent the starting and operation of the machine in case the interlocking
device fails.

2. Always acquire its position to guard the dangerous part before the machine
can be started.

3. Remain closed in position until the dangerous part is completely at rest.

1.2.4 Safety by using fixed guards

These guards either for man integral part of the machine or are tightly secured to
them. They should be made to have rigid construction and should be so placed that
any access to the dangerous parts of the machine is totally prevented in the running
condition of the machines.

Steel sheets can be advantageously used and they facilitate an easy fabrication of
guards and are lighter in weight.
In some cases the fixed guards are made adjustable in order to accommodate
different kinds of works or sets of tools. In some cases the fixed guards are
provided at a distance from the danger point.

1.2.5 Safety by using distance guards

The principle of a distance guards is that a fencing, enough high, is made of bars,at
a suitable distance from the machine such that even if the operative, by chance,
extends his hands over it, his fingers, clothes or any part of the body does not reach
within the area of dangerous parts. An additional measure of safety, some sort of
tripping device is also usually incorporated to stop the machine quickly in case of
an accident.

1.2.6 Safety by using automatic guards

The principle of an automatic guard is that its operation is actuated by some

moving part of the machine.

It may linked that the part will automatically bring the guard in protecting position
before the operation of the machine starts. The design of the guard is such that it
automatically forces the operative away from the dangerous area of work before
the operation starts and does not permit his access to the area again until and unless
the machine stops. It may be noted that due to enough time being required for their
operation, this type of guards are not suitable for quick-acting and fast-running
machines. Their use is largely favoured for heavy and slow acting machines like
heavy power presses.