This document discusses machine guarding and provides examples of guarding printing presses and slitters. It describes an incident where an operator was severely injured after reaching into an unguarded pinch point of a printing press. It then outlines the types of hazardous motions found on machinery and various methods of safeguarding, including fixed guards, interlocked guards, gates, and two-hand controls. The responsibilities of management, supervisors and employees are also summarized. The goal is to prevent injuries by ensuring all dangerous moving parts are properly safeguarded.

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Machine
Guarding
Julian Kalac, P.Eng
June 11, 2013

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Scenario
• Printing press
• 42 year old operator with 20 years exp.
• Pinch point – 150psi
• Distance from pinch point to safety stop
– 8 feet
• No guards in place
• Operator goes to remove a paper jam……..

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Result
• Hospitalized for 1 week
• Rehabilitation for 4-6 months
• Severed tendons & nerves
• Laceration to bone
• Missing nerves & tendons
• Loss of sensation
• Loss of range or motion
• Finger tips permanently bent
*These are only
The physical problems

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Any machine part, function, or
process which may cause
injury must be safeguarded
Rule to Remember

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New Guards
for Printing Press

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Types of Hazardous Mechanical
Motions
and Actions
• Rotating (including in-running nip points)
• Reciprocating
• Transverse
• Cutting
• Punching
• Pinching
• Shearing
• Bending

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Rotating Motion
• Common rotating mechanisms
– Collars
– Couplings
– Cams
– Clutches
– Flywheels
– Shaft ends
– Spindles
– Horizontal/vertical shafting

18. Dangerous moving parts in these basic areas require safeguarding:
1. Point of operation
2. In running nip points
3. Pinch points
4. Power transmission
5. Other moving parts
Where Dangerous Mechanical Hazards Occur

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Types of Machine Guards
• Guards
– Fixed
– Interlocked
– Adjustable
– Self-adjusting
• Devices
– Presence sensing
• Photoelectrical (optical)
• Radio frequency (capacitance)
• Electromechanical

20. Machine Guards
• Machines guards are there to protect from
exposed hazards
• Guarding MUST never be removed unless
under supervision and locked out
• If a Guard is missing notify your supervisor
immediately
• Never bi-pass the guarding!
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Types of Machine Guards
• Devices (cont’d)
– Pullback
– Restraint
– Safety controls
• Safety trip control
– Pressure-sensitive body bar
– Safety trip rod
– Safety tripwire cable
• Two-hand control
• Two-hand trip
– Gates
• Interlocked
• Other

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Fixed Guard
Provides a barrier - a permanent part of the
machine, preferable to all other types of guards.

23. Parts rotating in opposite direction
In-running nip point hazards
Rotating and tangentially moving
parts
Rotating Parts
Point of contact between a
chain and a sprocket

24. Examples of 3 Types of Motion
Rotating and fixed parts
Transverse motion
Rotating and tangential motion

25. Grinder Safety
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26. Grinder Safety (cont)
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27. Cutting Saws
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Point of contact Blade not guarded

28. Max Gap Allowable gaps Grinder

29. Guarded vs Ungarded Saw
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30. PINCH POINTS

31. LAMINATOR GUARDING
Interlocked Guarding
Mesh Guarding

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Adjustable Guard
Provides a barrier which may be adjusted to
facilitate a variety of production operations.
Bandsaw blade
adjustable guard

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Self-Adjusting Guard
Provides a barrier which moves according to
the size of the stock entering the danger area.
Circular table saw
self-adjusting guard

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Two-Hand Control
• Requires constant,
concurrent pressure to
activate the machine
• The operator’s hands are
required to be at a safe
location (on control
buttons) and at a safe
distance from the danger
area while the machine
completes its closing
cycle

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Gate
• Movable barrier device which protects the operator at the
point of operation before the machine cycle can be started
• If the gate does not fully close, machine will not function
Gate Open Gate Closed

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Safeguarding by Location/Distance
• Locate the machine or its
dangerous moving parts so that
they are not accessible or do
not present a hazard to a
worker during normal operation
• Maintain a safe distance from
the danger area

37. Example #1
Slitter guarding using guards

38. Front view of guard

39. Example #1 SLITTER GUARDING USING MECHANICAL
GUARDS

40. Example #2
Slitter guarding using light curtains

41. Example #2
Slitter guarding using light curtains

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Machine Safety Responsibilities
• Management
– ensure all machinery is properly guarded
• Supervisors
– train employees on specific guard rules in their areas
– ensure machine guards remain in place and are functional
– immediately correct machine guard deficiencies
• Employees
– do not remove guards unless machine is locked and tagged
– report machine guard problems to supervisors immediately
– do not operate equipment unless guards are in place

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Training Questions
• Why must machines be guarded?
• What are the machine hazards ?
• When can you remove a guard?
• What to do if a guard is missing or
damaged?

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Any machine part, function, or
process which may cause
injury must be safeguarded
Rule to Remember

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QUESTIONS???