Mechanical Hazards & Safeguarding

Chapter 8

Goetsch

Mechanical Hazards

Associated with power mechanics
New technology has created new hazards
Automation has removed many hazards

Mechanical Injuries

Cutting and tearing
Shearing
Crushing
Breaking
Straining and Spraining
Puncturing

Cutting and Tearing

Contact with a sharp edge
Seriousness related to the damage done to the epidermis, veins, arteries, muscles or bones

Shearing

Same action as scissors
Removal of digits, hands, arms

Crushing

Squeeze point types

Non-rotating, two hard surfaces

Nip points - in running points

Rotating machinery, objects drawn into the machinery

Bone breaks

Fractures

Simple - skin not broken

Compound - skin broken

Complete - bone 2 or more pieces

Incomplete - bone cracked

Straining and spraining

Strain - muscles over-stretched or torn
Sprain - torn ligaments in a joint

Punctures

Object penetrated the body and pulls straight out

Safeguarding

Goal - minimize risks of accidents due to machine-human contact
Individual making contact with the machine
Flying objects, liquids, kickbacks
Machine malfunction

Requirements of safeguarding

Prevent contact
Be secure and durable
Protect against falling objects
Create no new hazards
Create no interference
Allow safe maintenance

Safeguards

Point-of-operation guards

Fixed - permanent barrier

Interlocked - shut down machine when moved

Adjustable - change depending on production requirements

Safeguards

Point-of-operation devices

Photoelectric

Electromechanical

Pull back

Restraint

Safety trip

Two hand controls

Gates

Safeguards

Feeding and ejection devices
Goal is to keep the operators away from the danger zones

Robots

Entrapment of worker
Impact by robot arm
Impact with object carried by the robot
Work envelope
Gates and pressure sensitive mats most popular

Lockout/Tagout

Protect against unintended startup
Lockout - padlock that can only be removed by the person who installed it
Tagout - used where lockout not appropriate

Effective lockout/tagout

Attention to detail
Extensive training
Reinforcement of training
Disciplinary action

General precautions

Training in operation and maintenance of their machines
Training in emergency procedures
Know where and how to activate emergency shutdown controls

General precautions

Inspection and maintenance of safeguards
Supervisors ensure safeguards in place
Operator teams should be trained together

General precautions

Appropriate dress
Avoid shortcuts that violate safety practices
Non-operators should be made aware of the dangers and emergency procedures

Corrective action

Immediate specific action