Twelve characteristics, design principles, specifications, basic requirements or good guarding practice for machine guarding are:-
- With its primary purpose of protection, it should also facilitate the work it should be convenient, reliable arid not hampering the work or rate of production.
- It should fully satisfy the legal provision is prescribed it should conform the standards, be a complete guard at incomplete or giving any access to the part to be protected. It should be as close as possible.
- It should allow for for oiling, inspection, adjustment and repair. If it repairs opening for this purpose, it should be easily and quickly replaceable.
- It should be suitable and effective to the machine. It should not weaken the machine.
- It’s would be the withstand wear, shock, vibration long use with minimum maintenance require. This becomes more important and if it factors becomes more important.
- If dusting is possible as in case of machine of wood, rubber, brass, cast iron etc. Apart from the guard, dust suction device should also be fitted as a special guarding.
- It should be of proper material and construction it should well fitted, fire and co-resistance material is preferable.
- It should be free from self hazard such a sharf, nails, splinters, more opening noise, vibration etc.
- It should be inter-locking type, the machine will not start till it is not closed and soon if it is open.
- If visual watch of operation is necessary, it should be transparent and yet durable.
- It should fulfill a special requirement depending upon it’s purpose distance guard must immediately trip the machine, It may be difficult to fulfill all these requirement provide sufficient protective distance, Trip guard must immediately trip the machine etc. It may be fulfill all these requirement but it is desirable that safety engineers must guards by keeping above points in mind. If possible to provide guard without interfering production, safety should be preceded over production similarly when complete protection is not in complete, protection should prefer to no protection.
- It should be fail-shape if it fails or be the stop the machine or at least it gives warning (alarm to stop the machine)
Types of Guard:
- Safety by construction – A shaft end or any part without nip, spoke, nail or protruding projection moving at very slow speed, any sliding or link mechanism moving at very slow speed without danger of trapping or crushing, a power operated sliding door which will stop or return at touch are some of the examples of safety by construction.
- Safety by position – When dangerous parts are so situated by height, depth or position that it is normally difficult to touch them they are called safe by position overhead transmission machinery, dangerous parts out of reach because of height or covered by some structure so as to prevent access or contact, are generally called safe by possible.
- Built by safety
- Safety by machine controls
- Safety by precaution and maintenance
- Safety by guarding prime mover
Transmission Parts and points of operation:
Fix guard of fancing
- Totally enclosure
- With limited excess
- With adjustment excess
- Distance or barrier guard
- Mechanical interlocking
- Electrical interlocking
- Trip guard
- Control guard
- Mechanical type sweep know or puss away guard
- Photo electric cell type
- To hand control
- Optical censor
- Electromagnetic sensor
- Mechanical feed (conveyor)
- Feed tools (tong, magnetic device)
- Non repeat device
- Pedal guard