GeneralFuze, Mine, Combination, M6 & M7
LAND MINES
Section V
FUZES AND FIRING MECHANISMS

24. COMBINATION FIRING DEVICE M1.

a. Description. This is a nonelectric mechanism designed for use with a trip wire or a pressure arrangement. The devcie (figs. 18 and 19) consists of a head, body, and base (figs. 11, 12, and 14). The base, containing the primer, has an extension to which an igniter or a detonator may be attached. The base is threaded below to screw into a mine or demolition block, and above to receive the body housing. The body contains a spring-loaded firing pin which passes through the head. The firing pin is grooved to receive the locking screw and release pin as it passes through the head and is drilled to receive the safety pin above the head. The pressure cap fits over the top of the firing pin.

b. Function. When the locking screw and safety pin are removed, the release pin, which bears in the groove in the firing pin, holds it against the firing pin spring. A pull of 3 to 6 pounds on the ring attached to the outer end of the release pin releases the firing pin. Also a force of 20 to 40 pounds on the pressure cap forces the release pin back, thus releasing the firing pin. Driven by the firing pin spring, the pin strikes the primer which explodes, sending a spurt of fire through the extension in the base, initiating the igniter or detonator attached thereto.

Figure 18 - Firing Devices

c. Installation.

(1) IN ANTIPERSONNEL MINES M2 AND M3. As issued with Antipersonnel Mine M2 the firing device has an igniter attached to the base. The base is separated from the body of the firing device and assembled to the mine. The firing pin assembly, designated FUZE, mine, antipersonnel, M2, is supplied with the mine but not assembled to it. As issued for the Antipersonnel Mine M3 the device is complete and has a blasting cap assembled. This assembly is designated FUZE, mine, antipersonnel, M3. In this case the fuze is packed separately, but in the same packing box with the mine. For installation, see paragraphs 17 and 18.

(2) FOR INSTALLATION IN OTHER CHARGES.

(a) Prepare and place the mine charge. In addition to the standard mines supplied, the mine charge may be a fragmentation hand grenade, primacord, bangalore torpedo, or any explosive which can be detonated by the Army special nonelectric cap or by primacord. The procedure to be followed is the same as for the placing of any demolition charge where a nonelectric cap is used. If the firing device and the charge are not to be placed together, primacord may be used to connect them, by taping or tying three turns around a demolition block or inserting the end of the primacord into a fuze hole and wedging it there with a twig or piece of wood. The other end of the primacord is formed into a short loop and taped securely to the blasting cap on the firing device. Necessary waterproof-ing arrangements should be made where the charge is exposed to the weather. If serve weather conditions are anticipated, or the installation is excepted to be subjected to weather of a long period, it is necessary to take additional steps to seal the connection between the firing device base and the blasting cap. A small amount of heavy grease, wax, cap-sealing compound, or any other suitable waterproofing material which is avail-able should be applied in making all joints.

(b) Remove the base containing the primer, leaving the safety screw and safety pin in place.

(c) Remove the cardboard protector tube from the tip.

(d) Slide the open end of a nonelectric cap over the projector on the base and crimp, using cap crimpers. This should be done carefully as only a tight crimp will result in a waterproof joint between the base and the blasting cap.

(e) Screw the base, with blasting cap attached, to the device.

(f) Insert the blasting cap into the charge or tape primacord to the cap.

Figure 19 - Combination Firing Device M1

(3) FOR USE AS A PULL TYPE FIRING MECHANISM.

(a) Anchor the firing device as close to the mine charge as possible.

(b) Install the trip wire. Always start from the far end. Fasten the trip wire to a peg, bush, or other anchor, and then lay it out toward the mine. There should be no tension on the trip wire. Before connecting the trip wire to the firing device, step off to the side and inspect to see the wire is not visible. Rearrange it, if necessary, so that it is not visible.

(c) Attach the trip wire to the firing device. It must place no tension on the device.

(4) FOR USE AS A PRESSURE FIRING MECHANISM (par. 26).

(a) Prepare the pressure trip installation, making sure that there is a firm attachment for the firing mechanism and that the pressure trip does not bear too heavily on the pressure cap.

(b) Attach blasting cap and prime charge as above.

(c) Install mechanism and pressure trip. Make sure that the installation is not detect-able.

(5) The final operation is to remove the locking screw while the safety pin is in place. If there is too much pressure or tension on the firing device the safety pin will tend to bind and the installation should be checked. If the safety pin does not bind, gently remove it and leave both safety pin and locking screw concealed near the mine in case it should be necessary to disarm and take up the mine.

GeneralFuze, Mine, Combination, M6 & M7