DESCRIPTION. The body houses a rotating disk used for setting the delay, a clockwork meachnism, a battery, and an electrical circuit with a match composition bridge.

The rotating disk has 21 graduations corresponding to the number of days of delay re-quired. The setting is accomplished by rotating the disk until the number corresponding to the number of days delay required corresponds with the pin which is held in tension against the side of the disk by the spring (A). (See fig. 277.)

The clockwork is geared to the rotating disk by gear wheels and is wound by to and for movements of the winding ring.

A bakelite cover is threaded onto the body over the time disk while a detonator is screw-ed into the bottom of the igniter.

OPERATION. When the slot in the time disk comes opposite the pin, the pin is forced into the slot by spring (A). This closes the electrical circuit between the casing and the battery and fires the match composition.

EMPLOYMENT. This igniter is used in conjunction with large scale demolitions where a long delay is required. Several of the igniters may be used on each charge. Although the charges are generally composed of blocks of cast explosives, these igniters will be im-bedded in pieces of plastic explosive which is in contact with the main cast charge.

Figure 277 – Long-Delay (21-day) Clockwork