USNBD, Bombs and Fuzes; Section III - Bomb Fuzes: M110, AN-M126A1

U.S.N.B.D. - UNITED STATES - BOMBS AND FUZES; PYROTECHNICS

SECTION III - BOMB FUZES

DATA:		ARMY-NAVY NOSE FUZES
		AN-M110A1 AN-M126A1
BOMBS USED IN
AN-M110A1	20 lb. AN-M41A1 Hi-Level
	Frag.
	115 lb. M70 Chemical bomb	(Service)
AN-M126A1	100 lb. AN-M47A2 Chemical	M110 (Obsolete)
	bomb.	M126 (Obsolenscen.)
FUNCTIONING	Instantaneous	MECHANICAL IMPACT
ARMED CONDITION	When safety block is gone.
FUZES USED WITH	None
ARMING TIME	260 vane revolutions
VANE SPANE	3.0"
MAX. BODY DIAMETER	1.7"
OVERALL LENGHT	AN-M110A1, 3-5/8" with booster.
	AN-M126A1, 3-1/16" with booster housing.
MATERIAL	Alumium body with steel safety blocks and striker.

GENERAL:

These two fuzes are identiacal in both construction and operation. The only differ-ence is that the booster is eliminated from the AN-M126A1. Instead of the booster, a steel zylinder, the same dimensions as the booster, is screwed into the base of the fuze body. This steel cylinder contain an enlarged firing train consisting of primer, upper detonator and lower detonator, which is seated against the tetryl burster of the chemi-cal bombs.

OPERATION:

When the bomb is dropped and arming wire pulled, vanes rotate. The vanes are po-sitively attached to the upper part of the stationary gear, which can rotate but cannot move in a vertical plane because of a collar which rides in a groove in the fuze body. As the vanes and stationary gear rotate about the ball race, the movable gear, which is threaded up inside the stationary gear also rotates. Both gears mean with an idler gear, and since the movable gear has one more tooth than the stationary gear, for each ro-tation the movable gear large one tooth, thus unscrewing downward from the station-ary gear. As the sleeve of the movable gear moves down, it releases the safety block, allowing the block to be expelled by centrifugal force. The sleeve is moved down far enough in 260 rotations of the vane to arm the fuze. On impact the striker ist driven down, overcoming the resistance of the firing pin spring and the firing pin initiates the explosive action instantaneously.

REMARKS:

The original designs, M110 and M126, had more teeth on the gears, and conse-quently required 570 vane revolutions to arm. They also had three safety blocks, each 120° segments, and the arming sleeve fitted in a groove in the blocks in the unarmed position, preventing them from falling out. The original designs also had larger vanes.

If the striker head is flush with the fuze body; the fuze is in a fired condition. In such condition, the striker should not be pulled away from the fuze, as the firing pin is sensitive and withdrawal might create aufficient friction to ignite the primer.