Machine Guarding29 CFR 1910.211 to 1910.219

Rule of Thumb

Any machine part, function, or process that may cause injury must be safeguarded.

Regulatory Requirements

Regulatory requirements found in 29 CFR 1910, Subpart O

Applies to specific types of equipment Delineates general requirements

Where Mechanical Hazards Occur

The point of operation In the power transmission apparatus Other moving parts

Hazardous Mechanical Motions

Rotating Reciprocating Transverse

Hazardous Actions

Cutting Punching Shearing Bending

Types of Rotating Mechanisms

Collars Couplings Cams Clutches Flywheels Shaft ends Spindles

Nip Points

Caused by rotating parts Causes include

– Parts rotating in opposite directions– Parts rotating tangentially– Parts rotating close to a fixed part

Types of Reciprocating Motions

Back and forth Up and down

Types of Transverse Motions

Straight and in a continuous line Examples include two pulleys and a belt

Cutting Actions

Include– Rotating motions– Reciprocating motions– Transverse motions

Types of Cutting Mechanisms

Band saws Circular saws Boring or

drilling machines Lathes Milling machines

Types of Punching Actions

A ram mechanism:– Blanks– Draws – Stamps

Used on metal or other materials

Types of Punching Equipment

Power presses Iron working equipment

Types of Shearing Actions

Uses a powered slide or knife Done to trim or shear metal or other materials

Types of Shearing Equipment

Shears that are operated:– Hydraulically– Mechanically– Pneumatically

Types of Bending Actions

Power is applied to a slide to:– Draw – Stamp

Used on metal or other materials

Types of Bending Equipment

Power presses Press brakes Tubing benders

Requirements for Safeguards

Minimum general requirements include:– Prevent contact– Secure– Protect from falling objects– Create no new hazards– Create no interference– Allow for safe lubrication

Classifications of Safeguards

Guards Devices Location/distance Feeding and ejection methods Miscellaneous aids

Types of Guards

Fixed Interlocked Adjustable Self-adjusting

Types of Devices

Presence Sensing– Photoelectrical– Radio frequency– Electromechanical

Pullbacks or Restraints

Types of Devices (cont.)

Safety Controls– Safety trip control

• Pressure-sensitive body bar• Safety tripod• Safety tripwire cable

– Two-hand control– Two-hand trip

Gates– Interlocked– Other

Location/Distance

Makes it virtually impossible to contact moving parts

Separates operators from the equipment Limited by the available workspace

Feeding and Ejection Methods

Automatic feed Semiautomatic feed Automatic ejection Semiautomatic ejection Robot

Miscellaneous Aids

Awareness barriers Protective shields Hand-feeding tools and holding fixtures

Quiz

1. Mechanical hazards occur at the point of operation, in the power transmission apparatus, and ____________.

2. Any moving part on a piece of equipment that could injure an employee should be guarded. True or False

3. Power presses are extremely dangerous because of the force necessary for them to operate. True or False

4. Shearing mechanisms can be operated with _____________, ___________, or ___________ energy.

5. As long as the guards remain in place, operators should not be trained on machine guarding. True or False

Quiz (cont.)

6. A robot is one type of automated feeding and ejection mechanism. True or False

7. Hazardous mechanical motions include _____________, ____________, and _____________.

8. Nip points are created when sliding mechanisms move back and forth. True or False

9. Cutting mechanisms include ____________________, ____________________ and ____________________.

10. Location and distance is not a classification of machine safeguarding. True or False

Quiz Answers

1. Mechanical hazards occur at the point of operation,in the power transmission apparatus, and in any other moving parts.

2. True. All moving parts that create a hazard should be guarded.

3. True. The force of a power press can destroy metal, let alone the human body.

4. Shearing mechanisms can be operated with hydraulic, mechanical, or pneumatic energy.

5. False. If operators work with equipment containing safeguards, they should be adequately trained on how to use them.

Quiz Answers (cont.)

6. True. A robot is a type of feeding and/or ejection method.

7. Hazardous mechanical motions include rotating, reciprocating, and transverse.

8. False. Nip points are created by rotating parts.

9. Cutting mechanisms include band saws, circular saws, drilling machines, lathes, and milling machines.

10. False. Location and distance is one of five classifications of machine safeguarding.