DESCRIPTION. The body casing, painted dark grey, is of seamless sheet metal con-struction. It is similar to the 55 fuze construction. The normal type fuze head is unpain-ted.

The polystyrene molding has been cut away in one place to accommodate the new iner-tia bolt switch. This switch is a piston plunger type operating against a creep spring. On static loading, a force of 260 g - 300 g is required to close the switch. Some fuzes have been found with a very short powder delay train.

There are two firing circuits charged one from each plunger. The circuit under the B plunger is fired by the usual impact switch and initiates a short delay. The circuit under the A plunger is fired through the inertia bolt switch. Safety switching is accomplished by depressing both plungers thereby disconnecting the reservoir condenser from the two firing circuits. (See fig. 150.)

The condenser roll is inserted from the regular practice. The leads from the condenser tags are embedded in the outer layers of paper.

OPERATION. The operation of this fuze is the same as for all normal electrical impact fuzes. If only the B plunger is charged, the regular impact switch fires a short delay. If both plungers are charged the inertia bolt switch fires for instantaneous action. Then if the inertia switch fails, the delay will still function and fire the main charge.

Figure 150 – (76) A Electrical Impact Fuze