(89)D Clockwork Aerial Burst FuzeZus.Z. 40 (Type II), Mechanical Antiwithdrawal Fuze
Chapter 2
Bombs Used in: SC 250 & 500 Under a (17), (17) A or B.
Color: Unpainted.
Material: Aluminum.
Possible Actions: Instantaneous, on withdrawal of (17) type fuze.
Principal Markings: Zus. 40.
Secondary Markings: AA 1940, 392, bmv 41.

DESCRIPTION. This fuze is designated as a protective device to prevent with-drawal of a time fuze from a bomb. The fuze its around the gaine of the time fuze which it is pro-tecting, and another gaine is threaded into the base of the Zus. 40. (See fig. 181.)

The device is cylindrical with a central opening in the upper surface to receive the gaine of the fuze which it protects. In one side of the wall is an arm attached to a spring-loa-ded striker sliding in a channel. This arm is restrained by the gaine of the Rheinmetall fuze. A detonator is located at the other end of this channel and is held position by a threaded brass plug. A small flash channel below the detonator leads to the booster pel-let. A small black powder charge intensifies the flash from the detonator. Located in a chamber below the striker is a spring-loaded detent held in position by a steel ball. The base of the Zus. 40 is closed by a plate threaded to receive a gaine. To prevent with-drawal of the Zus. 40 when the time fuze is removed, spring-loaded knife edges in this model are placed in the upper surface of the device. Two knives with piano wire springs bite into the sides of the fuze pocket and resist upward movement.

OPERATION. Before the fuze is placed in the fuze pocket, the striker is retained by the spring-loaded detent and ball. When the time fuze gaine is inserted into the top of the Zus. 40, the striker arm is forced back into the body of the Zus. 40. This moves the stri-ker back against its spring and removes the shoulder of the striker from the detent. On impact, the steel ball moves toward the nose of the bomb, forcing the detent upward through camming action. As soon as the ball is free from under the detent, the detent moves down and out of the striker cavity. The Zus. 40 is now armed. When the time fuze is withdrawn 0.6 inch the striker arm is freed, and the striker moves across to hit the detonator. The detonator fires the relay, which flashes through the hole to the gaine, exploding the gaine and the bomb.

Figure 181 – ZUS 40 (Type I) Mechanical Antiwithdrawal

(89)D Clockwork Aerial Burst FuzeZus.Z. 40 (Type II), Mechanical Antiwithdrawal Fuze