Pros and Cons of Safeguards Tool

Fixed Guards
Safeguarding Action	Pros	Cons
• Provides a barrier	• Can be constructed to suit many specific applications • In-plant construction is often possible • Can provide maximum protection • Usually requires minimum maintenance • Can be suitable to high production, repetitive operations	• May interfere with visibility • Can be limited to specific operations • Machine adjustment and repair often require its removal, thereby necessitating other means of protection for maintenance personnel
Interlocked Guards
Safeguarding Action	Pros	Cons
• Shuts off or disengages power, stops the moving parts 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	• Can provide maximum protection • Allows access to the machine for removing jams without time consuming removal of the fixed guards	• Requires careful adjustment and maintenance • May be easy to disengage
Adjustable Guards
Safeguarding Action	Pros	Cons
• Provides a barrier that may be adjusted to facilitate a variety of production operations	• Can be constructed to suit many specific applications • Can be adjusted to admit varying sizes of stock	• Hands may enter danger area – protection may not be complete at all times • May require frequent maintenance and/or adjustment • The guard may be made ineffective by the operator • May interfere with visibility
Self-adjusting Guards
Safeguarding Action	Pros	Cons
• Provides a barrier that moves according to the size of the stock entering the danger area	• Off-the-shelf guards are often commercially available	• Does not always provide maximum protection • May interfere with visibility • May require frequent maintenance and adjustment
Photoelectric Devices
Safeguarding Action	Pros	Cons
• Machine will not start cycling when the light field is interrupted • When the light field is broken by any part of the operator’s body during the cycling process, immediate machine braking is activated	• Can allow freer movement for operator • Simplicity of use • Used by multiple operators • Provide passerby protection • No adjustment required	• Does not protect against mechanical failure • Limited to machines that can be stopped
Radiofrequency Devices
Safeguarding Action	Pros	Cons
• Machine cycling will not start when the capacitance field is interrupted. • When the capacitance field is disturbed by any part of the operator’s body during the cycling process, immediate machine breaking is activated	• Can allow freer movement for operator	• Does not protect against mechanical failure • Antennae sensitivity must be properly adjusted; this adjustment must be maintained properly • Limited to machines that can be stopped
Electromechanical Devices
Safeguarding Action	Pros	Cons
• Contact bar or probe travels a predetermined distance between the operator and the danger area. • Interruption of this movement prevents the starting of machine cycle.	• Can allow access at the point of operation	• Limits movement of operator • May obstruct work space around operator • Adjustments must be made for specific operations and for each individual • Requires frequent inspections and regular maintenance • Requires close supervision of the operator’s use of the equipment
Pullback Devices
Safeguarding Action	Pros	Cons
• As the machine begins to cycle, the operator’s hands are pulled out of the danger area	• Eliminates the need for auxiliary barriers or other interferences at the danger area	• Limits movement of operator • May obstruct work space around operator • Adjustments must be made for specific operations and for each individual • Requires frequent inspections and regular maintenance • Requires close supervision of the operator’s use of the equipment
Restraint Devices
Safeguarding Action	Pros	Cons
• Prevents the operator from reaching into the danger area	• Little risk of mechanical failure	• Limits movement of operator • May obstruct work space • Adjustments must be made for specific operations and each individual • Requires close supervision of the operator’s use of the equipment
Safety Trip Controls
Safeguarding Action	Pros	Cons
• Stops machine when tripped	• Simple to use	• All controls must be manually activated • May be difficult to activate controls because of their location • Only protects the operator • May require special fixtures to hold work • May require a machine brake
Two-Hand Control
Safeguarding Action	Pros	Cons
• Concurrent use of both hands is required, preventing the operator from entering the danger area	• Operator’s hands are at a pre-determined location • Operator’s hands are free to pick up a new part after first half of the cycle is completed	• Requires a partial cycle machine with a brake • Some two-hand controls can be rendered unsafe by holding with arm or blocking, thereby permitting one-hand operation • Protects only the operator
Two-Hand Trip
Safeguarding Action	Pros	Cons
• Concurrent use of two hands on separate controls prevents hands from being in the danger area when machine cycle starts	• Operator’s hands are away from danger area • Can be adapted to multiple operations • No obstruction to hand feeding • Does not require adjustment for each operation	• Operator may try to reach into danger area after tripping machine • Some trips can be rendered unsafe by holding with arm or blocking, thereby permitting one-hand operation • Protects only the operator • May require special fixtures
Gates
Safeguarding Action	Pros	Cons
• Provides a barrier between danger area and operator or other personnel	• Can prevent reaching into or walking into the danger area	• May require frequent inspection and regular maintenance *May interfere with operator’s ability to see the work