DESCRIPTION. This German igniter is a firing device designed to function either as a pressure igniter or as a pull igniter. The igniter body has a base plug and a pressure head and houses a striker assembly. The base plug is threaded for attaching the igniter to a detoantor and it holds a percussion cap. To prevent the base plug from being unscrewed from the body, a set screw is provided. The head has a free fit to permit its rotation in the bushing, which is fixed to the body by a threaded collar. A pin is fixed to the head. The striker assembly consists of a striker, two shear pins, a pull pin, a metal guide, and a helical spring. The striker has a circular groove which receives the ends of the shear pins and the pull pin to hold the striker in the cocked position. Just above the groove are the beveled cuts. The cut is beveled to permit any pin under either beveled cut to be pushed out of the path of the striker. The guide is attached to the body by the screws and has two lugs. These lugs limit the rotation of the head by confining the movement of the pin, which is a part of the head, to a path between the lugs. The pull pin extends to the out-side of the body through an opening under which is engraved the word "zug" (pull). The igniter is provided with a safety key, which fits into the igniter hrough an opening under which is engraved the word "sich" (safe). (See fig. 259.)

The top of the head has a cut-mark and a slot beside which is engraved the word "druck" (pressure). Three setting marks "zug" (pull), "125 kg" and "45 kg" appear on the top of the bushing. The head may be turned so that the mark comes opposite any one of the three setting marks by using a coin or similar object in the slot. When the mark is op-posite each setting mark, the pin which protrudes slightly above the flange of the head fits into a small indentation on the underside of the bushing. There are three of these inden- tations to correspond to the three setting positions. The striker is engaged to the head by the pin so that it will rotate with the head. As the head, together with the stri-ker, is turned to each setting position, the pins and the pull pin ride in the groove. In this manner one or both of the shear pins and the pull pin can be brought in position to hold the striker. If the pin is positioned in one of the beveled cuts, it is not effective to resist the downward movement of the striker. The safety key is a strip of flexible metal which fits between the striker and the percussion cap. If the striker is accidentally released, a slot in the safety key will intercept the striker. If this happens, the safety key cannot be withdrawn and the igniter will not function.

Igniters recovered in Italy did not have firing pressure stamped on the setting, but had the letters Z for Zug or pull; S for Schwer or heavy; and L for Leicht for light. Firing pressure on these igniters were not verified as the igniters were not complete.

OPERATION. This igniter may be adjusted to operate under any of the three different settings described below. The igniter is armed first by adjusting the setting and then by removing the safety key from the igniter. A long wire or cord is attached to the loop on the safety key, and the safety key is pulled out from a safe distance. To set the igniter to fire at 275-pound pressure, turn the movable head so that the mark is opposite "125 kg". When the required load is applied, both shear pins are sheared and the pull pin is pushed outward as its ends ride the beveled cut, thus releasing the striker. The com-pressed firing spring drives the striker downward, setting off the percussion cap. To set the igniter to fire at 100-pound pressure, turn the movable head to that the mark is op-posite "45 kg".

Note that the setting pin is now stopped by the lug. When the required load is applied, one of the shear pins is sheared; the other shear pin and the pull are pushed outward as their ends ride the beveled cut. This release the striker and causes the device to fire as previously described. To set igniter to fire as a pull igniter, turn movable head to that the mark is opposite the word "zug". When the pull pin is withdrawn by a trip wire, thus re-leasing the striker, the two shear pins are pushed outward as their ends ride in the be-veled cuts; the firing is as described for the pressure igniters.

EMPLOYMENT. This igniter is specifed for use in the assembly of antitank, anti-vehicle, or antipersonnel mines.

Figure 259 – Z.D.Z. 29 Igniter – Pressure and Pull