DESCRIPTION. This mine is rectangular in shape, and its case and many of its compo-nent parts are made of cast iron. It consists of a box, a cover plate, a removable plug, and one or more firing mechanism. (See fig. 229.)

1. Box. The box is made of cast iron and its dimensions are the same as those given in the description of the mine. Within the box is placed the main charge consisting of 84 blocks of TNT. The charge weighs 37 pounds and is contained in a zinc or galvanized iron box, the lid of which is held in place by either a wire or a webbed strap. Three posts, which are drilled and tapped at the top, project vertically from the floor of the box and support a base plate which in turn supports the main firing mechanism. The base plate is screwed to the supports by studs. Holes are provided in the floor of the box for anchor-ing it in place by either bolts or stirrups. A centrally located hole is also provided, the take the standard pull igniter Z.Z. 35 for the purpose of connecting an additional explo-sive charge in the form of a booby trap. Adjacent to the top corners of the box and away from the firing mechanism end, journals are provided in which trunnions formed in the cover plate have bearing. The journals and the trunnions form hinges for the cover plate. The supporting plate is fastened by studs to the posts. A stud is screwed into the plate and supports a helical spring in a vertical position. The spring is formed from square section spring steel approximately 1/8 inch square.

2. Cover Plate. The cover plate fits into and covers the top of the box. When the cover plate is in position, the trunnions are fitted into the journals and a lug formed under the free (swinging) end of the cover plate rests on the helical spring which holds the cover plate level with the top edges of the box. One corner of the cover plate has a rectan-gular recess into which is fitted the removable plug. The cover plate is provided with top recesses into which road material may be inserted to match the surrounding road surfa-ces. The undersurface of the cover plate is deeply grooved or scored to form a grid so that the cover will form shrapnel when the mine explodes. The cover plate is also provi-ded with a pedal housing into which a pedal is inserted. The pedal is found with several short strings or wires attached to its end. The exact purpose of the pedal is not clear, but it is assumed that it is used to extract the safety pins of the firing mechanism by means of the strings or wires. It is stated in the latest information available that a pres-sure of 100 pounds on the pedal may fire the mine. However, the exact construction is not clear. The pedal may also fastened to a booby trap, and therefore great care must be taken in removing it from the cover plate. A U-bolt is provided on the top surface of the cover plate for lifting the plate.

3. Removable Plug. The removable plug is rectangular in shape and fits into the corner re-cess of the cover. To its underside is attached an eyed rod which projects through the hole of the cover plate when the plug is in place. On the top side of the plug is attached a U-bolt which is used to lift the plug. The plug provides access to a locking pin.

A. Main Push Igniter. Standard push igniter, type Z.Z. 35 is mounted on the base plate by being screwed into the hole provided for it in this plate. A detonator and booster charge is mounted beneath the plate. The booster charge is 4 inches long and 1 3/4 inches in diameter. When pressure is applied to the cover plate, the head of the igniter is depres-sed downward, and the igniter fires the detonator and booster charge and the main charge.

B. Pull Igniter. Standard pull igniter type Z.Z. 35 is used as a booby trap device for the mine. The ogniter is mounted on the base plate and is provided with a second detonator and booster charge mounted below the supporting plate. The projecting head of the pull pin is connected by a cord or wire to an auxiliary firing assembly. A dowel pin is mounted on the base plate. A small helical spring rests on the head of the dowel pin and is held in place by a sleeve which rides over the dowel pin. The closed head of the sleeve is provi-ded with a loop to which the wires is fastened. When the cover plate is in place, the lug presses on the eye loop, thus compressing the spring. To keep the sleeve from rotating, it is provided with a lug which rides in a groove formed in the dowel pin. The locking pin passes through the loop and is locked to the cover plate by a bracket. If the cover plate is lifted, the sleeve is pulled upward, and at the same time the wire pulls and fires the ig-niter. The igniter fires the detoantor and booster, which in turn explodes the main char-ge. Even if the locking pin is removed, care must be exercised not to lift the cover quick-ly, as the spring, which is in compression, will force the sleeve upward with sufficient strength to fire the igniter. This firing mechanism constitutes a booby trap.

C. Additional Booby Trap Devices. Pull igniters may be installed to provide booby traps while the mine is disarmed. A wire may be attached to the eye of the rod and to a pull igniter below the cover plate, which will be fired if the removable plug is extracted. It is also stated that pull igniters may also be inserted within the blocks of the charge. It is the practice of the Germans to insert, in each standard block of explosive, a threaded metal sleeve to accommodate a standard pull igniter. Thus any two blocks may be inter-connected by an igniter which will fire upon being separated. This also is of the nature of a booby trap. An additional firing device and charge may be connected to the hole in the base of the box, which will fire if the box is lifted. This also is considered a booby trap.

OPERATION. The mine is fired by a downward pressure exerted on the cover plate, which pivots on the trunnions. This pressure compresses the main pressure igniter, which fires the charge. The height of the pressure igniter head may be adjusted so that varying degress of compression of the helical spring, holding up the cover plate, will fire the mine. Thus, the mine may be set to fire under the weight of a man or reconnaissance vehicle, or it may be set so that it will explode only under heavy tanks. Also, when the mine is provided with booby traps it may be actuated in a number of different ways. The main booby trap is the pull igniter. The mine may also be fitted by lifting the removable plug when dismantling the charge, when removing the pedal, or when removing the box from its hole in the road.

EMPLOYMENT. This mine is used for road blocks where action has been static for a peri-od of time. The length of time required to lay the mines prevents their effecitve use in fast moving warfare.

Figure 229 – Heavy Antitank Mine