N2 Fitting and Machining Theory|Hands-On! 3
Manholes in the floor, scaffolding and uneven surfaces must have warnings on and near them to prepare and warn anyone in the area. Te area should be cordoned off if possible.
Projecting shaſts
When a shaſt projects beyond the machine on which it is being machined or beyond where it is stored, it must be enclosed by a guard with a warning on it to prevent any possible accident.
Transmittion belts
All drive belts which include chains and cables or ropes must be completely enclosed by a guardrail to prevent any person touching a belt on purpose or by accident. Should the guard have to be opened for maintenance or for any other reason, the guard must be fitted with an automatic switch that switches the drive off immediately.
Te condition of safety appliances such as guards on machinery
All safety guards and all equipment must be maintained in good condition at all times. Te guards must be in good working condition especially if they are the type that can be opened when necessary and automatically switched off at the source of the drive.
Machine guards are grouped together in classes such as: • fixed, permanent guards that are only removed or opened when maintenance is done • transmission guards that cover belts, chains, pulleys, ropes, gear or rotating shaſt drives
• point of operation guards that cover moving saw blades, guillotine blades, punches, dies in presses, pneumatic or hydraulic clamping devices and bending brake jaws
• automatic guards that open and close automatically when an operation is completed to allow access to a chuck or other similar device to replace the completed part with a new blank
• lock out or interlocking guards that prevent the machine from operating until the operator has placed both his hands on release buttons, well clear of the operation area. Tis type of guard is oſten fitted with electronic beams that when broken, stop the operation from proceeding.
Te importance of the guards mentioned above is so great that it would be illegal to operate without them.
A good guard should have the following properties and functions:
• Itmust comply with the minimum requirements of the Department ofManpower and Mineral and Energy Affairs and NOSA.
• It must ensure maximum protection for operators of the machines and mechanical and electrical devices and equipment to which they are fixed.
• It must not affect the efficient operation of the machine or device on which it is mounted.
• Where necessary the guards should be hinged to allow access to the chains, belts and gears etc. for regular maintenance.
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