EMPLOYMENT: Mechanical Impact Base Fuze used in German 7.5-cm A.P.C. shells (See fig. 608.)

DATA:

Over-all length: 3.875 inches.

Maximum diameter: 2.188 inches.

Threaded length: 0.875 inch.

Number of threads: 6 RH.

CONSTRUCTION: This fuze is similar in exterior construction to the 7.5-cm (small type) fuze. It has a fixed striker and an inertia pellet containing a primer in the top. It has the standard German centrifugal arming mechanism. Four flash holes around the striker lead to a compression chamber which is closed by a brass disk with a pin-point hole in the center. The top of the fuze closing plug is threaded externally to accept an aluminum cap which has a center hole lining up with the hole in the disk. This hole leads to another detonator composed of lead styphnate, lead azide, and PETN/wax.

ACTION: Centrifugal force causes the centrifugal segments to expand the expanding spring ring thus releasing the inertia pellet. Upon impact the inertia pellet, containing the primer, goes forward impinging upon the fixed firing pin. The flash, after passing through the four holes around the striker, enters the compression chamber. When the pressure has been buil up sufficiently, the flash passes through the pin-point hole in the closing disk firing the detonator.

REMARKS: The building up of pressure in the compression chamber determines the delay in the fuze.

Figure 608 – Fuze for 7.5 cm-Pzgr. (Large Cavity)