DESCRIPTION. The body of the device is made up of two oblong blocks of molded explo-sive, held together by two hollow brass bolts. The explosive, a greyish-black substance of smooth texture, is believed to be one of the many forms of Nipolit. The inner surfaces of both blocks bear molded recesses to retain the metal striker mechanism. A threaded detonator well is positioned at one end to receive the cap and detonator assembly. Four holes pass through the charge, two at either ends, for the bolt and two for the safety pins. The cap and detonator assembly is believed to consist of a hollow threaded plug of the same explosive material. The cap and detonator drop into the plug and are then screwed into the wall. (See fig. 275.) The striker mechanism consists of a stamped sheet metal housing, a striked retainer arm, striker spring and striker. In the armed position the striker spring and striker are positioned in the tubular striker guide at the base of the housing and are restrained from firing by a notch or detent in the retaining arm which bears against the shoulder of the spring-loaded striker. The retaining arm pivots at one end on a small bolt positioned above the detent. The two safety pin holes in the metal housing coincide with holes that pass through the explosive body. The upper safety pin passes directly over the retaining arm and prevents it from pivoting. Another hole passes through the tubular base of the housing and is an added safety precaution in that it pre-vents the striker from striking the cap.

OPERATION. After the device has been placed under the object to be booby trapped, the safety pins are removed. When the external weight is lifted, the striker retaining arm, under the pressure of the striker spring, pivots upward releasing the striker and firing the percussion cap. The cap in turn fires the detonator and the main charge. No booster re-quired.

EMPLOYMENT. This device is designed for use as a booby trap and can be readily used beneath ordinary household objects as well as mines and other suitable objects.

Figure 275 – All-Explosive Pressure Release Device