machanical safety

Machine guarding

Where Mechanical Hazards Occur Dangerous moving parts in these three basic areas need safeguarding:

1.The Point of Operation- The point of operation is that point where work is performed on the material, such as cutting, shaping, boring or forming of stock.

2. Power Transmission Apparatus- Power transmission apparatus are all components of the mechanical system that transmit energy to the part of the machine performing the work. These components include flywheels, pulleys, belts, connecting rods, couplings, cams, spindles, chains, cranks and gears.

3. Other Moving Parts- Other moving parts include all parts of the machine that move while the machine is working. These can be reciprocating, rotating and transverse moving parts, as well as feed mechanisms and auxiliary parts of the machine.

Hazardous Mechanical Motions and Actions- Rotating Motion, Reciprocating Motion, Transverse Motion, Cutting Action, Punching Action, Shearing Action, Bending Action

Requirements for Safeguards

Safeguards must meet these minimum general requirements:

1.Prevent Contact- The safeguard must prevent hands, arms or any other part of a worker’s body from making contact with dangerous moving parts. A good safeguard system eliminates the possibility of the operator or another worker placing his or her hands near hazardous moving parts.

2. Be Secured to the Machine- Workers should not be able to remove or tamper easily with the safeguard, because a safeguard that can easily be made ineffective is no safeguard at all. Guards and safety devices should be made of durable material that will withstand the conditions of normal use. They must be firmly secured to the machine.

3. Protect From Falling Objects- The safeguard should ensure that no objects can fall into moving parts. A small tool that is dropped into a cycling machine could easily become a projectile that could strike and injure someone.

4. Not Create New Hazards- A safeguard defeats its own purpose if it creates a hazard of its own, such as a shear point, a jagged edge or an unfinished surface that can cause a laceration. The edges of guards, for instance, should be rolled or bolted in such a way that they eliminate sharp edges.

5.Not Interfere With Job Performance- Any safeguard that impedes a worker from performing the job quickly and comfortably might soon be overridden or disregarded. Proper safeguarding can actually enhance efficiency since it can relieve the worker’s apprehensions about injury.

6.Allow for Safe Lubrication of the Machine- If possible, one should be able to lubricate the machine without removing the safeguards. Locating oil reservoirs outside the guard, with a line leading to the lubrication point, will reduce the need for the operator or maintenance worker to enter the hazardous area.

types of mechanical safety process/equipment

We can group safeguards under five general classifications:

1. Guards 

A. Fixed 

B. Interlocked 

C. Adjustable 

D. Self-adjusting

2. Devices 

A. Presence Sensing 

i. Photoelectric (optical) 

ii. Radiofrequency (capacitance) 

iii.Electromechanical 

B. Pullback 

C. Restraint 

D. Safety Controls 

i. Safety trip control 

a. Pressure-sensitive body bar 

b. Safety tripod 

c. Safety tripwire cable 

ii.Two-hand control 

iii.Two-hand trip 

E. Gates 

i. Interlocked 

ii. Other

3. Location/Distance

4. Potential Feeding and Ejection Methods to Improve Safety for the Operator 

A. Automatic feed 

B. Semi-automatic feed 

C. Automatic ejection 

D. Semi-automatic ejection 

E. Robot

5. Miscellaneous Aids 

A. Awareness barriers 

B. Miscellaneous protective shields 

C. Holding fixtures and hand-feeding tools