Mechanical Hazard Flashcards
What are OSHA’s top 10 violations?
- Fall protection
- Scaffolding
- Hazard communication
- Respiratory protection
- lockout/tagout
- Electrical -wiring
- Powered Industrial Trucks
- Ladders
- Electrical-general requirements
- Machine Guarding -General requirements
What are common mechanical injuries?
· cutting and tearing
· shearing
· crushing
· straining and spraining
· puncturing
What is Point of operation?
The point where work is performed on the material (cutting, shaping, boring, or forming of stock must be guarded
What is Power Transmission
-All components transmitting energy to the part of the machine performing the work
-flywheels, pulleys, belts, connecting rods, coupling cams, spindles, chains, cranks, gears etc.
What are Rotating Hazards?
-collars, couplings, cams, clutches, flywheels, shaft ends, spindles, horizontal or verticle shafts
· drill bit is an example
What are Nip Points?
- Parts are rotating in opposite direction with parallel axes can cause nip points
- Nip Points are cause between rotating and tangentially moving parts
- Between rotating and fixed parts which create a shearing, crushing or abrasive action
on belt conveyers the most important danger points are the nip points
What is Reciprocating?
· Hazards caused when a worker may be stuck or caught between a moving and stationary part during:
-back and forth motion
-up and down motion
What is Transverse?
· Hazards caused when a worker may be stuck or caught in a pinch or shear point.
· Ex: conveyor type systems at saw mills, manufacturing assembly lines etc.
How are the hazards of Punching, shearing, and Bending Actions called?
· When power is applied to a slide or knife for blanking, drawing, stamping, shearing, or forming metal or other materials
· Hazards exists at the point of operation when a sock is inserted, held, & withdrawn by hand
Risk Reduction- Hierarchy of Control
- Elimination of substitution
- Engineering controls
- Awareness Means
- Training and Procedures
- Personal Protective Equipment
What are the 4 different types of safeguards?
- fixed guard
- interlock guards
- interlock grands
- adjustable guard
What are safeguards?
“Barriers that prevent entry into the point of operation or other hazard area” -ANSI
What are fixed guards?
Prevent and/or control access to hazard areas
· Around, under, through, over (AUTO)
· Selection of material
· safe distance
· color
-gotcha stick
What is a gotcha stick? (fixed guards)
A gotcha stick measures the allowable barrier opening size based on distance from the point of operation
What are interlocked guards?
· shuts off or disengages power and prevents starting of the machine when the guard is open
· Should require the machine to be stopped before the worker can reach into the danger area
What is the issue with interlocked guards?
The problem with this guard is the safety feature can be bypassed by ‘fake’ closing guard with screw driver
What are adjustable guards?
Provides a barrier which may be adjusted to facilitate a variety of production appearances
ex: blade guard
What are 6 general requirements for safeguards?
- Remain secure
- Create no new hazards
- Allow safe lubrication
- create no interference
- Protect from falling objects
- Prevent contact
What are some point-of-operation devices? (POD)
· photoelectric
· Radio frequency
· electromechanical · pullback
. restraint
. Safety trip
· two-hand controls
*there are others
What is a photoelectric (optical presence, sensing) POD?
Photoelectric devices are optical devices that shut down the machine whenever the light field is broken
What are the limitations with Photoelectric (optical presence, sensing) POD devices?
· Do not protect against mechanical failure
· Require frequent calibration
· can be used only with machines that can be stopped
· Do not protect workers from parts that may fly out of the point of operation area
· Only used on machines that can be stopped before a worker can reach the danger area
What is blanked related to photoelectric devices and other devices?
· Means bypassing a portion of the sensing field of a presence-sensing device
· Different types of blanking are available for different types of operations
What is enabling devices?
-Provides the margin of safety during troubleshooting, set up programming or servicing, or robotic, or automated machinery, with no other safeguarding means, are possible or practical
-Test have shown that human reaction to an emergency may be to release an object or to hold on tighter
-Not a substitute for a guard
What are pull back devices (POD)?
-Pull the operator’s hands out of the danger zone when the machine starts to cycle
-They limit operator movement, must be adjusted for each individual operator and require close supervision
What are restraint devices? (POD)
-Hold the operator back from the danger zone- with little risk of mechanical failure
-They also limit the operator movement, must be adjusted for each individual operator, and require close supervision.
-can only reach so fast so hands don’t get injured by equipment
What are safety trip devices? (POD)
-Safety trip devices include tripwires, trip rods, and body bars, which stops the machine went tripped.
-Devices located around the perimeter of or near the danger area
-Operator must be able to reach the cable to stop the machine
What are two hand controls? (POD)
-Require the operator to use both hands concurrently to activate
-Ensures that hands cannot strain the danger zone
-Some can be tampered with and made operable using only one hand
What are safety floor mats? (POD)
-Pressure sensitive electric switches (shuts equipment down)
-A stop signal is initiated when an object is sensed in the danger area
What is distance in relation to POD?
-Makes it impossible to contact moving parts -Separates operators from the equipment
-Limited by the available workspace
What are issues with safety floor mats? (POD)
-Can step over
-Expensive
-easily damaged by things that fall on the floor
-Surface beneath must be flat, (if not short it out)
What are the hazards associated with robot safeguards?
-entrapment of worker between a robot and solid surface
-Impact with a moving robot arm
-Impact with objects ejected or dropped by the robot
What is the best safety option for robot safeguards?
-a physical barrier around the entire perimeter of a robots work envelope (best option)
-various types of shutdown guards can also be used
What are sone facts/rules about emergency stops?
· shall remain unguarded
· shall be prominent & accessible from all operator position
· colored red
· suitably marked
· Require manual reset before restarting
· Not to be used for normal stopping
· Not to be relied upon for isolation
· Not an alternative to guarding
What do you do when conducting periodic audits?
· Compare with previous assessment report
· machine location or uses may have charged
· Location and proper use of guards
· Modify guarding (if needed) to accommodate process or usage changes
· check machines made prior to 1971
· check machines made overseas (ISO)
What is abrasive wheel machinery? (1910.215)
· Commonly used machinery
· Guarding of abrasive wheel
· Mounting
What are safety precautions when using abrasive
- eye shields vs goggles
-loose clothes/accessories
-Work rest
-tongue guard
-“Ring test” by tapping a chel with the nonmetallic handle of a screwdriver
What is the ring test for abrasive wheels?
-All abrasive wheels must be closely inspected and ring tested.
-you tap and listen for ring tone
What is the gist of mechanizal hazards?
Where there is a risk of exposure to dangerous parts during:
· operation
· examinative
· lubrication
· adjustment
· maintenance
that risk must be eliminated, or, where it cannot be eliminated, minimized
