Machine guarding tips, By B C Das


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The need for machine guarding, practices and devices and includes information on hazardous machine components, motions, and actions,Safety Awareness, It is sharing of knowledge. By Bimal Chandra Das, Rtd. AGM (Safety), Bokaro Steel Plant,/ Bokaro. Kolkata

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Machine guarding tips, By B C Das

  1. 1. Machine GuardingPrime MoverAny engine motor or other appliance which generates or otherwise providespowerTransmission MachineryAny shaft, wheel, drum, pulley, system of pulleys, coupling, clutch, driving belt orother appliance or device by which the motion of a prime mover is transmitted toor received by any machinery or appliance.Machinery :Includes prime movers, transmission machinery and all other appliances whereby power is generated, transformed, transmitted or applied.Securely Fenced :• Not to be interpreted as little securely fenced, or reasonably fenced or moderately fenced. The employer is not be able to defend himself by saying that it is impossible for commercial or mechanical reasons to fence the machine or part of a machine.• The obligation imposed by Sec. 21 is absolute (complete, free from controls & conditions), it is not for court to water down the absolute character of the obligation by imposing considerations as to practicability of the requirement or possible substantial loss of efficiency or utility of machinery• The carelessness, the indolence (negligence), the inadvertence (laziness), the weariness (tiredness) and even the disobedience of a worker are things which an occupier of a factory can and is expected to foresee and should, therefore, provide against such happenings, fencing of machinery must be secured.• Constantly maintained and kept in position - Sect. 94 Applies Basic Requirement of Mechanical Guard• It must be sturdy to prevent damage to the guard from external source or interference.• It must permit required maintenance, operation without necessitating excessive labour for dismantling and assembling the guard.• It must be properly mounted. The mounting must be rigid to objectionable rattle or interference with working parts.• It should be designed so that there are no detachable parts, which if removed and replaced would reduce guarding effectiveness.• It should be easy to inspect. 1
  2. 2. DangerousA machinery or part thereof is dangerous if in the ordinary course of its workingdanger may reasonably be anticipated from it when working without protection,taking into account the various factors incidental to its working, includingcarelessness of the workmen. Default as to make the employer liable to a penal consequenceThe obligation of the employer is absolute and it does not require the proof ofexistence of men’s area. When of a proper safeguard is provided and someone notknown to the employer, removes it without his knowledge or consent, still theemployer would be made liable for penal consequence. Machine GuardingA guard is a device to prevent injury to a person working on or near a movingmachinery.(e.g. Coupling guards, V-belt guard, Conveyor tail end guard etc.)Where dangerous parts of machinery are not made safe at the design stage byconstruction or by position, they should be guarded or protected in such a way as toprevent access at all times when danger exists. Machinery Hazards • The violent ejection of a work piece. • Contact with the revolving wok piece. • Contact between a work piece. • The free fall of a part which is at rest? • Contact with hot substance. • Entanglement in materials. • Entanglement of loose clothing, hair or materials • Projected from pockets. Dangerous Machinery Parts • Rotating shafts & spindles. • Trap or nips at ingathering rotating parts. • Nips between belts and pulleys. • Projection on moving parts. • Discontinuous rotating parts. • Revolving drums or cylinders with dangerous surface. • Worms and spirals. • Surface of fast running parts. • Band type cutting tools. • Revolving cutting & abrading tools. • Reciprocating tools of the press or punch type. • Misc. shearing and trapping hazards. Principles of Machine Guarding • Provide positive protection. • Prevent all access to the danger zone during operation. • Cause no inconvenience to the operator. • Be suitable for the job & the machine. 2
  3. 3. • Constitute a built-in feature. • Allow for m/c oiling, inspection, adjustment & repair. • Withstand long use & normal wear & shop with minimum maint • Protect against unforeseen operational conditions, not only against normally expected hazards. • Must be properly mounted. Factories Act 1948Sec. 21(Fencing of Machinery) In every factory dangerous parts of machinery, e.g. Every moving part of a Prime Mover & every Fly Wheel connected to a Prime Mover. The headrace & tailrace of every water wheel & water turbine Every parts of transmission machinery. Every parts of electric generator, a motor etc. Every dangerous parts of any other machinery. Shall be securely fenced by safe guards of substantial construction which shall be constantly maintained and kept in position, while the parts of machinery, they fencing, are in motion or in use.Sec 22 (Work on or near Machinery in motion) When it becomes necessary to examine any part of machinery, while the machinery is in motion, such examination or operation shall be carried out only by a specially trained adult male worker wearing tight fitting clothing, whose name has been recorded in the register prescribed in this behalf. No woman or young person shall be allowed to clean, lubricate or adjust any part of a prime mover or any part of transmission machinery while the machine is in motion.Sec 26 (Casing of New Machinery) In all machinery driven by power and installed in any factory after the commencement of this act:- Every set screw, bolt or key on any revolving shaft, spindle, wheel or pinion. All spur, worm and other toothed or friction gearing which does not require frequent adjustment, while in motion, shall be completely encased.Sec 23 : Employment of young persons on dangerous machines No young persons shall be required or allowed to work at Any machines which is in motion, unless he has been fully Instructed as to the dangers arising in connection with the machine & the precaution to be observed and a) has received sufficient training in work at the machine or b) is under adequate supervision by a person who has a thorough Knowledge & experience of the machine.Rule 59(B) of BFR – 1950 also specifies the same. 3