|
|
| Japanese Explosive Ordnance – Bombs, Bomb Fuzes, Land Mines,
Grenades, Firing Devices and Sabotage Devices |
| Chapter 2 – Section 2 |
| Navy Bomb Fuzes |
| Type 3 - Nose Initiator A-3 (e) |
| Bombs in which used: Temporarily designated type 99 No. 6 smoke. |
| Color: Steel, except for brass nose cap. |
| Over-all length: 5 3/8 inches (less detonator). |
| Over-all width: 2 1/8 inches; vane span, 3 5/8 inches. |
|
Material of construction: Steel except for brass nose cap, arming sleeve, and striker spindle. |
|
Position and method of fixing in bomb: Screwed into nose fuze pocket and tightened with a wrench. |
|
Components of explosive train: Detonator. |
|
Delay times: None. |
|
Threads: 10 threads per inch, RH, 1 7/8 inches in diameter. |
|
Description: The fuze consists of the fuze body, arming vane assembly, striker spindle and detonator holder. |
|
The fuze body is of one-piece construction. It houses the striker spindle which is held in position by a locating screw and a brass shear wire. The upper portion of the spindle is threaded and a steel firing pin is screwed into the lower end. The arming vane assembly consists of a nose cap, arming vanes and arming sleeve. The arming sleeve is internally threaded and screws onto the spindle. Its length of travel is limited by a stop screw threaded into the top of the spindle. The nose cap and four arming vanes are attached to this sleeve by four short screws. |
|
The lower end of the fuze body is grooved circumferentially. The cup-like detonator hol-der is secured to the fuze body by two screws which fits into this groove. |
|
A heavy wire eyelet is attached to the side of the fuze body and serves as a guide for the starting wire. The starting wire is soldered to the nose cap in two places and gives an initial turn to the arming assembly when the bomb is dropped. A safety fork fits into the upper portion of the fuze body, one prong of which extends up through eyelets of arming vane assembly to prevent premature vane rotation. |
|
Operation: On release of bomb, the arming wire pulls the starting wire through the eye-let, breaking it loose at the soldered points and simultaneously imparting an initial rota-tion to the arming vane assembly. In seven revolution, the arming sleeve rises up the striker spindle to lock against the stop screw and arm the fuze. On impact, the entire as-sembly (vanes, nose cap, sleeve, and spindle) is driven inward, shearing the shear wire and the firing pin pierces the detonator. |
|
Figure 119 – A-3 (e) Bomb Fuze. |
|
|
 |
