57. 21-Day Clockwork Delay Fuze, J. Feder 504 (Uhrwerkszünder, J. Feder 504)

a. Description. The 21-day clockwork delay fuze J. Feder 504 (fig. 59) is a mechanical type. The fuze is 3 3/8 inches in diameter and 7 5/8 inches high. It has an aluminum case containing a spring-loaded striker actuated by a clockwork mechanism through a trip lever. There are two dials for setting the delay period. The dial marked in red (rot) is for the number of days (tage). It can be set for any number of days up to 21. The dial marked in black (schwarz) is for hours (stunden). It is graduated in 1/4-hour increments up to 24 hours. Two screws are provided for a hole in the side of the base of the fuze. The screw marked blind merely closes the hole, allowing the safety spring to push the safety block under the shoulder of the striker shaft. This is a positive safety. The screw marked scharf (armed) is the arming screw. It pushes the spring-loaded safety block away from the striker shaft just far enough so the shoulder of the striker shaft will go through the hole in the safety block. A modified model of the J. Feder 504 is fitted with an electrical-control base consisting of two wire leads connected to an electric detona-tor placed in a charge. The modified version also has two terminals in the top of the fuze for wiring into an electrical circuit.

b. Employment. This device is used for the delayed detonation of large charges in areas abandoned to an opposing force.

c. Functioning. At the end of the delay period, determined by the setting, a lever arm on the rotating control disk on the clockwork bears against the trip lever, disengaging the head of the striker shaft. The released striker fires the percus-sion cap, the detonator and the main charge.

Figure 59. 21-day clockwork delay fuze, J. Feder 504

d. Installing and Arming.

(1)

Test the fuze by setting it for 15 minutes to see that it is functioning corectly. Re-cock the fuze with the recocking device.

(2)

Unscrew the cover and wind the clock by turning the knurled winding knob clock-wise.

(3)

Turn the knurled time-setting knob in the top of the fuze to the desired delay.

(4)

Attach the detonator to the percussion-cap holder, and insert the fuze in the charge.

(5)

Remove the screw marked blind in the base of the fuze, and screw in the arming screw marked scharf (armed).

(6)

Turn the release ring above the setting indicator window so the red mark is oppo-site geht (go).

e. Neutralizing.

(1)

Remove the arming screw marked scharf, which allows the spring-loaded safety block to move under the shoulder of the striker shaft. This keeps the striker from descending far enough to striker the percussion cap, in the event the trip lever is accidentally disengaged from the head of the striker shaft.

(2)

Turn the red mark on the release ring from geht (go) to steht (stop).

(3)

Remove the fuze and the detonator from the charge.

f. Packing. This fuze is packed in a black wooden box stenciled J. Feder 504. The perus-sion-cap holder and the re-cocking device are carried in the welled blocks (fig. 60).

Figure 60. 21-day clockwork delay fuze, J. Feder 504, packed in the standard carrying case.