Mechanical Action Fuzes Flashcards
What are the types of physical safety blocks?
Positive Safety - designed to positively prevent final initiating action
Organic Safety - designed to prevent initiating action
What are the descriptions of Normally Open (NO) and Normally Closed (NC)?
The normal state of rest for the switch with no outside influence
What is a Safe Arm/Separation Switch?
A switch which allows for a person to safely set the device and arm it without being there or disturbing the device
What is the Arming/Functioning Switch?
Is a switch which actually functions the device (does the work)
What will cause an Electromagnetic relay to function?
- Battery Decay (Collapsing Circuit)
- Anti-Disturbance (Weak Coil)
- Cutting a coil wire or taking out the coil battery
What is the best description of a tripwire?
A tripwire is nothing more than an extension of a switch/fuze
What should you do when dealing with tripwires?
Trace both ends of the wire before cutting
What indicates a membrane or tin foil switch?
Two wires going to nowhere
What is an Anti-Disturbance switch?
A mechanism used to sense any movement to function the firing train, this is the most hazardous to a Bomb Technician
What improvised switches use a taut tripwire?
A clothespin or mousetrap
How does a barometric switch operate?
By a change in atmospheric pressure
What type of switch would a bomber use as an anti-disturbance switch?
Vibratory, tilt
What causes a bi-metal switch to function?
Changes in temperature
What type of switch would a bomber use as an anti-disturbance switch?
Vibratory, Mercury, or ball
What causes a bi-metal switch to function?
Changes in temperature
What two ways can a mousetrap fuze be used in a hazardous device?
Electrical circuit using striker as contact. Percussion type using striker as firing pin.
What mechanical type by function is considered to be the most hazardous?
Anti-Disturbance
What is normally employed in a circuit containing a trembler or vibratory switch to provide an arming delay?
A clock or timer
What could prevent a clock from not functioning a device?
Paint or coating on the hands, lack of power or forgetting to wind the clock
What is the maximum delay using the minute hand on a clock? Using the hour hand on a clock?
59 minutes
11 hours 59 minutes
Why is it important that the screw does not come in contact with the face of the clock when using the clock hand method to fire a device?
If the screw comes in contact with the face of the clock, the firing circuit would be completed
When using the clock hand method, how is the time delay changed from minutes to hours?
By removing the minute hand
Why do many clock devices misfire?
The bomber forgets to scrape insulation paint from contacts and hands
What must be assumed if a clock is heard running in a device?
That the device is either armed or fired by the clock
What is the best way to describe a switch mechanism?
Type by function
