Mechanical Action Fuzes

Question 1

What are the types of physical safety blocks?

Answer 1

Positive Safety - designed to positively prevent final initiating action
Organic Safety - designed to prevent initiating action

Question 2

What are the descriptions of Normally Open (NO) and Normally Closed (NC)?

Answer 2

The normal state of rest for the switch with no outside influence

Question 3

What is a Safe Arm/Separation Switch?

Answer 3

A switch which allows for a person to safely set the device and arm it without being there or disturbing the device

Question 4

What is the Arming/Functioning Switch?

Answer 4

Is a switch which actually functions the device (does the work)

Question 5

What will cause an Electromagnetic relay to function?

Answer 5

• Battery Decay (Collapsing Circuit)
• Anti-Disturbance (Weak Coil)
• Cutting a coil wire or taking out the coil battery

Question 6

What is the best description of a tripwire?

Answer 6

A tripwire is nothing more than an extension of a switch/fuze

Question 7

What should you do when dealing with tripwires?

Answer 7

Trace both ends of the wire before cutting

Question 8

What indicates a membrane or tin foil switch?

Answer 8

Two wires going to nowhere

Question 9

What is an Anti-Disturbance switch?

Answer 9

A mechanism used to sense any movement to function the firing train, this is the most hazardous to a Bomb Technician

Question 10

What improvised switches use a taut tripwire?

Answer 10

A clothespin or mousetrap

Question 11

How does a barometric switch operate?

Answer 11

By a change in atmospheric pressure

Question 12

What type of switch would a bomber use as an anti-disturbance switch?

Answer 12

Vibratory, tilt

Question 13

What causes a bi-metal switch to function?

Answer 13

Changes in temperature

Question 14

What type of switch would a bomber use as an anti-disturbance switch?

Answer 14

Vibratory, Mercury, or ball

Question 15

What causes a bi-metal switch to function?

Answer 15

Changes in temperature

Question 16

What two ways can a mousetrap fuze be used in a hazardous device?

Answer 16

Electrical circuit using striker as contact. Percussion type using striker as firing pin.

Question 17

What mechanical type by function is considered to be the most hazardous?

Answer 17

Anti-Disturbance

Question 18

What is normally employed in a circuit containing a trembler or vibratory switch to provide an arming delay?

Answer 18

A clock or timer

Question 19

What could prevent a clock from not functioning a device?

Answer 19

Paint or coating on the hands, lack of power or forgetting to wind the clock

Question 20

What is the maximum delay using the minute hand on a clock? Using the hour hand on a clock?

Answer 20

59 minutes

11 hours 59 minutes

Question 21

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?

Answer 21

If the screw comes in contact with the face of the clock, the firing circuit would be completed

Question 22

When using the clock hand method, how is the time delay changed from minutes to hours?

Answer 22

By removing the minute hand

Question 23

Why do many clock devices misfire?

Answer 23

The bomber forgets to scrape insulation paint from contacts and hands

Question 24

What must be assumed if a clock is heard running in a device?

Answer 24

That the device is either armed or fired by the clock

Question 25

What is the best way to describe a switch mechanism?

Answer 25

Type by function