The firing device Mk I is designed for use in con-nection with anti-personnel mines, booby traps, or other demolition charges.

GENERAL:

This is a mechanical device designed for firing explosive charges by means of pres-sure or by release of pressure. The method of activation is dependent on the manner in which the device is set.

DESCRIPTION:

The principal parts of the device are the body, trigger pin, firing pin, base, trigger eye, and the knurled nut. The projection of the trigger pin extending down into the body has two slots with an inter-connecting hole which is large enough to permit the firing pin to pass through. When the device is set, the groove of the firing pin is engag-ed in either the upper or lower slot of the trigger pin. The trigger eye threads into the lower end of the trigger pin and can be used with a trip wire for functioning by either pull or tension-release dependet upon the method in which the device is set. The knur-led nut is the safety device to prevent premature firing.

INSTALLATION:

Attach the cap to the device and insert in the explosive charge. If device is actua-ted by pressure or pull on a trip wire, the trigger pin should be in the 'out' position and held up by the trigger spring; a trip wire can be attached to the trigger eye. If device is to be actuated by pressure release or tension release, the trigger pin must be in the 'depressed' position with the groove of the firing pin engaged in the upper slot. The trigger spring is under compression when the trigger pin is depressed and a restraining load of 31 pounds on the trigger pin or a tension of 31 pounds on the trip wire attached to the trigger eye is necessary to hold the pin in this position. When device is set, the knurled nut is removed and the device is in an armed condition.

REMARKS:

The device can be set to function by either pressure and pull or by pressure release and tension release. The method of actuation being dependent on whether the trigger pin is in the 'out' or 'depressed' position, the trigger pin is moved until the hole is moved in line with and releases the firing pin. The cocked firing pin is driven on to the percus-sion cap by the firing pin spring.