DESCRIPTION. The modified (70) B fuze is similar to the normal (70) B, with the follow-ing exceptions:

A. An arming vane stem, with an eight-bladed arming vane attached, is fixed to the arm-ing spindle by two screws in the normal manner;

B. No inertia spring is fitted;

C. The stud which forms the driving wheel pivot is provided with right-hand, instead of left-hand threading;

D. In storage, a thin wire secures the arming vane to the safety pin. (See fig. 189.)

OPERATION. When the arming vanes are released, the vanes rotate and with-drawn the arming spindle. When the spindle has been withdrawn about one-quarter inch, the es-capement locking spring is freed and the clockwork mechanism commences to arm the fuze.

After about the 5 1/2 seconds, the driving wheel stop pin is brought to bear against the nib of the release block, and the clockwork is stopped by this engagement. The fuze is then fully armed.

Any subsequent disturbance of the fuze or bomb will cause the fuze to function in a manner identical to that described for the normal (70) B.

Figure 189 – (70) B Modified Antidisturbance Fuze