Introduction to Basic Manufacturing Processes and ... - always yours

34 Introduction to Basic Manufacturing Processes and Workshop Technology
industries such as foundries, chemical , paper and sugarcane etc. Lack of adequate ventilation,
high speed of work because of huge work load, more number of working hours and over and
above them the tendency of the employer to insist for over time work, inadequate rest periods
in between works, noise, bad odor and flash coming from the nearby machinery, equipment
or processes, and poor housekeeping are also personal factors.
A large number of accidents can be avoided if proper safety measures and safety rules
are adopted in manufacturing areas. Some of the important causes of accidents involve
violation of safety rules, not using of safety devices, improper use of gadgets and machine
controls, non-development of safety working habits, ignorance of the operation of tools, machine
and equipments operation, unsafe working conditions, monotony and work-relating stresses,
wear and tear of the functional components, explosive and inflammable material etc.
3.6 COMMON SOURCES OF ACCIDENTS
A large number of revolving, rotating, reciprocating and moving parts of machinery can be
said as the sources of danger and require guarding for protection against accidents. Extensive
studies reveal that some characteristic groups of dangerous parts are acting as common
sources of accidents in workshops. Many such major sources are as under.
1. Revolving parts, viz. pulley, flywheels, worms, worm wheel, fan, gears, gear trains,
gear wheels etc.
2. Projecting fasteners of revolving parts; like bolts, screws, nuts, key heads, cotters
and pins etc.
3. Intermittent feed mechanisms, viz., tool feed of planer; table feed of a shaper, ram
feed of power presses and similar other applications.
4. Revolving shafts, spindles, bars, mandrels, chucks, followers and tools like drills,
taps, reamers, milling cutters, and boring tool etc.
5. Rotating worms and spirals enclosed in casings, such as in conveyors and revolving
cutting tool, like milling cutters, circular saw blade, saw band, circular shears and
grinding wheels, etc.
6. Reciprocating tools and dies of power presses, spring hammer, drop hammers, and
reciprocating presses, reciprocating knives and saw blade such bow saw, shearing
and perforating machines and the cutting and trimming machine and power hacksaws
etc.
7. Moving parts of various machines, like those of printing machines, paper-cutters
and trimmers, etc.
8. Revolving drums and cylinders without casing, such as concrete and other mixers,
tumblers and tumbling barrels, etc.
9. High speed rotating cages such as in hydro-extractors.
10. Revolving weights, such as in hydraulic accumulator or in slotting machines for
counter-balance.
11. Nips between meshing racks and pinions of machine parts
12. Nips between reciprocating parts and fixed components, such as between shaper
table and the fixture mounted on it or a planer table and table reversing stops, etc.
13. Nips between crank handles for machine controls and fixed parts.