Possible Actions: Long delay time – 3 to 135 minutes delay after impact. Set for 5 to 120 minutes delay with ± 10% accuracy.

DESCRIPTION. The L 17 Bm fuze has a cylindrical body with an inner flange at the lower end to serve as a seat for the aluminum sleeve containing the normal (17) B type inver-ted clockwork, and internally threaded at its base to receive the gaine. The clockwork release mechanism, which takes the place of the electric section of the (17) B, is loca-ted just above the clockwork. This mechanism contains a Y-shaped release plate with the release plate spring between the arms of the Y. One of the arms of the Y retains the spring loaded balance wheel stop plunger. The other arm retains the spring loaded safety plunger, which holds the safety pawl under the firing pin shoulder. The release plate is centrally pierced to accept the end of the safety pin. The base of the Y rides in a guide slot and limits the lateral motion of the release plate. The compressed release plate spring tends to force the release plate away from the tops of the plungers which bear against the arms of the Y. This action is prevented as long as the safety pin is in place.

Closing piece, centrally pierced to take the safety pin, closes the top of the fuze body. The safety pin is held in place in the fuze by an aluminum plate, which is attached to the safety pin and locked to the closing piece by a retaining washer. A pull ring is attached to the top portion of the safety pin.

OPERATION: On withdrawal of the safety pin, the release plate spring forces the freed release plate arms clear of the balance wheel plunger and the safety plunger. Both plun-gers, under the influence of their respective springs, are forced upward allowing the clock to start and at the same time allowing the safety pawl to move from under the striker shoulder. The remainder of the fuze operation is the same as in the (17) A. (See fig. 155.)

Figure 155 – Z 17 Bm. Mechanical Clockwork Fuze