Monday, 7 November 2016

Italian Explosive Ordnance - Mines and Traps

Italian Explosive Ordnance

Mines and Traps

 Italian anti-personnel mines are operated by pressure or trip wires.  They were often difficult to detect, especially those operated by pressure in which only a portion of the lid or igniter may appear above the ground.  The Italians used bakelite and wood in the construction of some mines to prevent detection by magnetic instruments.

Anti-tank mines vary in appearance.  They are tubular, rectangular, or circular in shape.  Some are made of bakelite or wood to prevent detection.

Improvised mines seem to have been the Italian specialty in the field.  They used a majority of the improvised mines in Abyssinia, since the supply of standard mines was apparently limited.  Most of these mines were of wooden construction and used blocks of TNT for the explosive.  Sometimes shells were used for explosive and shrapnel for mines.

Picket Mine - Anti-Personnel Mine

Overall length (w/ picket): 17.6 inches
Overall length (w/o picket): 5.7 inches
Body diameter: 1.6 inches
Type of filling: TNT
Weight of filling: 100 grams
Total weight: 1.75 pounds

Description: The mine proper consists of a thin sheet metal cylinder around which is wound the strip metal loading.  The mine is mounted on a wooden picket and contains a 100-gram cartridge of TNT.  The mine is closed by a screw-on lid which carries the spring-loaded striker.

Riveted to the underside of the lid is the stirrup-shaped holder into the center of which is pressed the detonator-locating tube.  Passing diametrically through the lid, through slots in the side, is the aluminum cap holder, which is located in the armed and unarmed positions by the spring.  The coiled end of the spring engages in the groove in the armed position and in the groove in the unarmed position.

The loops at the ends of the cap holders enable the cap holders to be pulled into the armed position by remote control and at the same time prevent it from being pullet out completely.

Operation: To arm the mine, the striker is pulled out and a pin is inserted in the lower hold.  A trip wire is attached to the pin.  Then a detonator cap is inserted in the cap holder, and the holder pulls into the armed position.

Functioning: The trip wire is pulled, and the spring-loaded striker hits the detonator.

Mine B-4 - Anti-Personnel Mine

Overall length: 8 inches (approx..)
Type of filling: TNT
Weight of filling: .25 pounds
Total weight: 3 pounds

Description: The mine consists of two cylinders, one inside the other.  The space between the walls is filled with scrap metal.  The outer cylinder is flattened on one side, where there are six sharp projections for attaching the mine to a tree or post.  Two clips are provided with fireproof cord for securing the mine by special rings.

The cylinders are held together at their common base and by a cover at the top.  Into one end of the brass moulding screws a brass cap carrying the striker and the spring.  Below this, there is the percussion cap in the holder which is inserted from the side.  The lower portion of the moulding takes the detonator and the charge.  The open end of the moulding is closed by the plug.  The cavity between the brass moulding and the inner cylinder is filled with powdered TNT.  The trip release system consists of a trip-key having a ring at one end to which the cords are attached.

The key is held by the grooves in the brass cap so that it can move slightly in a direction parallel to the end of the mine.  This allows the key to fit into the groove on the striker when in the armed position.  A ring guides the cords which are wound on a bobbin, the latter being covered by a hinged flap, held closed by the pin.  The pin is used as the safety pin before setting the mine.

There is a special mechanism for detonating the mine, when a cord attached to the trip release is cut.  This mechanism is in the form of a hammer on the eye and stretching it under sufficient tension to hold the hammer at least 4 mm from the end of the trip-key.  When the cord is cut, the hammer drives the trip-key forward, releasing the striker.  This hammer is not provided on all B-4 mines.

Italian Bakelite and Wooden 1 Lb Mine - Anti-Personnel Mine

Overall length: 5.5 inches
Overall width: 2.5 inches
Overall height: 1.5 inches
Type of filling: TNT
Weight of filling (wooden): .33 pounds
Total weight (wooden): 1 pound

Description: These two mines are similar except that one case is bakelite and the other is wood.  The igniter used has a spring-loaded striker held in the cocked position by a trip-key and has a cap and detonator leading into the main charge.  The lid of the mine has, in one end, a slot which fits around the striker and rests on the trip-key.  The mine also contains metal fragmentation plates on three sides of the charge.

Operation: One to five pounds of pressure on the hinged lid presses the trip-key out of the hole in the striker.  This action releases the striker, which is driven by the striker spring into the cap, detonating the main charge.

Ratchet Mine (Railroad Mine)

Overall length: 9.1 inches
Overall width: 6.1 inches
Overall height: 11.8 inches
Type of filling: Unknown
Weight of filling: 5.1 pounds
Total weight: 18 pounds

Description: The mine consists of two parts: the explosive container and the housing for the ratchet mechanism.  A hinged wooden device with the leather strap is provided for carrying the mine.  The wooden base is screwed to the base of the mine, and a loop in the strap holds the ratchet winding key.

The explosive container of the mine is fitted with a short skirt which is a sliding fit over the upper portion of the housing.  The two parts are attached to each other by two bolts and held apart by two springs, which are canvas-covered to insure their free movement when buried below ground.  The bolt heads are protected by the covers.

Through the top of the housing projects a spring-loaded plunger which operates the ratchet mechanism.  The striker, which initiates the detonation of teeth on its periphery.  This latter may be set to release the striker after any desired number up to 59 depressions of the explosive container.  The setting is made by the use of a key inserted in the hole situated below the setting observation window of the side of the mine.

The mine is designed for use under railway tracks, and the ingenious use of lead shot in the hollow spring-loaded platform insures a continuous rigid underside of the railway sleeper or rail.  The lead shot is inserted before laying the mine by removal of the screw in the center of the platform.  The platform is released when the mine has been positioned by removing the retaining pin.

Repeated operations of the ratchet mechanism by successive wheels of the same train is obviated by means of a delayed return of the ratchet pawl.  Provision is made for the attachment of an additional igniter by the screw-threaded adapter in the side of the explosive container.

Railway Mine

Overall length: 12 inches
Overall height: 4 inches
Type of filling: Gelignite

Description: This mine is made of a light alloy.  The lid, which is attached to the body by four bolts, is recessed to take the four bolts with hexagonal nuts.  The lid is supported on four springs and thus holds the striker away from the detonator.

In the unarmed condition, the striker with its ring is screwed into a recess in the side of the mine.  When arming the mine, the striker is placed in position over the shoulder.

Operation: Pressure on the lid forces the springs down, and the striker pierces the detonator, setting off the main charge.

Wooden Box Mine (Anti-Tank)

Overall length: 9.5 inches
Overall width: 8 inches
Overall height: 3 inches
Type of filling: Gelignite
Weight of filling: 2.5 kilograms
Total weight: 3.3 kilograms

Description: The mine consists of a wooden box which houses the explosive charge, a false lid, two igniters, and a separate wooden cover.  The explosive charge smells strongly of almonds; it consist of 24 cartridges, weighing 100 grams; is 5 inches long and 1 and 1/2 inches in diameter.

In the false lid are two holes, each 1 inch in diameter to receive the igniters.  Igniters have an aluminum alloy body which tapers slightly and has a mushroom shaped head.  The head is recessed to accommodate a steel washer, through which passes the shank of the striker.  The striker spring is maintained compressed between this washer and the striker head by means of a copper shear pin.

Below the striker is the detonator and the <?> is a push-fit into the base of the igniter.  On the underside of the mine cover are two metal plates located above the igniters and intended to <?> upon the strikers.  The mine cover is held in position by two wire retaining straps, which can rotated about the pins, securing them to the mine body.  All the parts are nailed together.  The mine is creosoted inside and out.

Operation: Pressure from 185 to 380 pounds on the cover shears the copper shear pins and the springs drive the strikers onto the detonators.

Four-Igniter Mine - Anti-Tank Mine

Overall length: 12.25 inches
Overall width: 10 inches
Overall height: 6.25 inches
Type of filling: TNT
Weight of filling: 11 pounds

Description: Four holes in the lid of this box accommodate four igniters, and the mine is completed by the addition of a false lid which consists of a movable pressure platform attached to a wooden frame by means of canvas.

When assembled, the framework is secured to the mine body by four clips, and the pressure platform rests on top of the four igniters with the canvas fully stretched.  The whole mine is painted for camouflage.  There is a single rope carrying handle.

Two types of igniters have been used in this mine.  One consists of a bakelite cone to which a bakelite lid is cemented.  A projection below the cone fits into an ordinary detonator, and the latter is then pressed on.  Within the cone is a small paper cylinder containing small pieces of hard limestone mixed with a small quantity of a chlorate flash mixture.  Pressure on the mine lid, the bakelite cones, and friction between the hard limestone and the chlorate mixture produces a flash which ignites the detonators, initiating the mine.  The other igniter is also bakelite, but is of more robust construction.

The base of the body is screw-threaded to take the plug which retains the detonator.  The detonator contains a cap, and a thin bakelite washer is inserted above this cap to give clearance for the striker needle and to insure that the detonator is held securely by the plug.

The striker holder rests on a conical boss within the body of the igniter, and the latter is closed by a push-fit cover.  The igniter functions when pressure on the lid of the mine causes the igniter body to break down and force the needle onto the cap.  Trials have shown that the mine, when fitted with this igniter, functions under a static load of approximately 300 pounds.

Operation: Pressure on the lid causes the igniters to function, detonating the main charge.

Anti-Tank Mine B-2

Overall length: 3 feet 6 inches
Overall width: 5 inches
Overall height: 4.7 inches
Type of filling: TNT
Weight of filling: 7 pounds
Total weight: 33 pounds
Firing pressure (On each spring): 220 pounds

Description: This mine, the latest development of older types "S.C.G." and "hinged lid", consists of a welded sheet-metal box with a metal lid resting on two springs.  The lid has two openings covered by hinged flaps corresponding to the positions of the striker assembly and the wire-tensioning screw.

At the ends of the box are charges, each consisting of eight 200-gram slabs of TNT.  On the underside of the lid are welded two short lengths of steel tube to fit into springs; two similar lengths of tube are welded on the base of the box; all four serve to locate the springs.

The explosive compartments and the foundation of the ignition mechanism are wood.  In the center of the lid, a knife is located directly above the guides.  Through these guides passes a tension wire, fastening the striker to a brass adjustable hook.

The striker mechanism consists of a body with a slot for the percussion cap and holder, and the striker and spring.  The nut retains one end of the spring; the thread takes the nut which retains the detonator (open and toward the percussion cap);' a short length of F.T.D., and a long length of D.T.D. connecting the detonator with a second charge.

A detent with a spring provides against premature firing in the event of damage to the tension wire, and, when the lid is depressed, insures normal function by pressure on the lever, which releases the detent.  This additional safety device is not found on all types.

A safety pin placed on a hole in the body of the striker remains in position until the mine is loaded, the hinged flaps are closed, and the mine is covered with earth.  The mine functions when pressure on the lid overcomes the resistance of springs, the cutting blade descends to sever the wire holding the striker, and the lid depresses the detent lever.

1. Type S.C.G. differs in that the lid has only one opening and has a small charge.
2. Type (Hinged Lid) was the earliest type, was smaller, and was made of wood.

V-3 and V-5 - Anti-Tank Mines

Overall length: 3 feet 8.9 inches
Overall width: 2.4 inches
Overall height: 2.7 inches
Type of filling: TNT
Weight of filling: 6 pounds
Total weight: 17 pounds

V-3: The mine is made of sheet steel, its body strengthened by two partitions.  The charge extends between two firing mechanisms.  The cover is secured to the body by concave-headed nuts, engaging on actuating bolts positioned by springs resting between a nut on the underside of the cover and a plate covering the firing mechanism.

When the nuts beneath the lid are screwed down, the springs compress, increasing the pressure required to operate the mine.  Unscrewing the nuts makes the mine more sensitive to pressure, as little as 22 pound weight can be made to trip the striker.  The underside of the cover has two knives engaging in guides provided to take copper pins.  (A weight of 264 pounds is required to shear the pins.)

At each end of the body are cocking grips, pulled to cock the firing pins.  The mechanism is shown.  When the striker is held by a cotter on a U-shaped spring clip.  A percussion cap is accommodated in a holder which is inserted in a hole in the side of the mine.  The body, held there by a blade retaining spring engaging in the slot.  The actuating pin inserted through a hole in the side of the body is the connection between an actuating bolt and the U-shaped spring clip carrying the cotter.

The pressure applied to the mine cover forces down the actuating bolt against the spring which comes into contact with the actuating pin causing a U-shaped spring clip to depress against the retaining spring.  The flange thus freed allows the striker to initiate the percussion cap and fire the detonator.

V-5: Similar to V-3, except for reduction of charge to 2 pounds of cylindrical <?>hole charge, omission of shear wire, and inversion of parts so V-5 has appearance of V-3 upside down.

Pignone Type I and Type II - Bakelite Anti-Tank Mines

Type I
Overall diameter: 13 inches
Diameter of casing: 11.87 inches
Overall height: 5.12 inches
Type of filling: TNT
Weight of filling: 7 pounds
Activating pressure: 110 pounds

Type II
Overall diameter: 13 inches
Diameter of casing: 11.87 inches
Overall height: 5.5 inches
Type of filling: TNT
Weight of filling: 7 pounds
Activating pressure: 300 pounds

Description: The mines are constructed of moulded bakelite; both types are of waterproof design.  Metal parts in the mines when armed are:
1. The case of the detonator.
2. The brass striker pellet and its helical spring.
3. The brass bush which houses the striker pellet(?), two steel balls, and brass shear pins.
4. A perforated steel bar which slides <?> the striker from the detonator <?> the <?> position.
5. Brass tumblers in the igniter <?>
6. Nine steel helical creep springs <?> the pressure plate.
7. In Type I, the steel <?> supporting the pressure plate.

Type I:  The casing <?> is in two halves, top and bottom <?> 5/32 inch and 7/32 inch thick.  <?> a central circular chamber for the <?>.  The top is strengthened <?>.  <?> are assembled with an <?> circumferential <?> sunk joint and an inner spigoted joint.

The outer joint has rubber sealing ring and is secured by hollow plastic rivets passing through 12 pairs of lugs.  The inner joint is secured by a <?> plug threaded into the center tube formed in the top half of the casing; this joint is sealed by a rubber gasket under the flange of the plug.

The plug also gives access to the booster charge and detonator, placed in the central chamber closed at the top by the base of the igniter assembly.  A webbing carrying the handle is attached to the casing by wire loops which pass through the hollow rivets in two pairs of lugs.  There are two filler plugs threaded into 1 and 1/8 inch diameter holes in the bottom.  The holes might be adapted for anti-lifting igniters; they are, diametrically opposite, approximately 2 and 1/2 inches from the edge, but are not placed in any fixed position relative to the handle.

The igniter assembly slides in the central tube formed in the top half of the casing and is retained by a locking ring.  A rubber ring seals this joint.  The pressure plate, 5/32 inch thick, is heavily ribbed underneath and is the full diameter of the mine casing.  It rests on the top of the igniter assembly and is held in position by steel wires which are looped through four lugs, set at 90 degrees around the mine, and fastened with two plastic rivet instead of one.

The air space between the pressure plate and the top of the main casing is closed, around the circumference, by a strip of impregnated canvas fixed by two steel wires.  The igniter assembly and arming arrangement are closed by the cap screwed into the pressure plate.

Type II: The main casing is similar to that of Type I.  The pressure plate, ribbed on the underside, is only 5 and 1/2 inches in diameter; it is 3/16 inch thick.  It bears on the top of the igniter assembly, as in Type I, but on the outside circumference is held by the ring which screws into a threaded socket, formed on the top of the main casing.  The igniter assembly is sealed by two rubber rings, the latter making a joint due to the upward pressure from the helical creep springs in the igniter.

A third type of bakelite mine is stated to have been produced by Pignone.  It was similar to Type I, but smaller and having a 1 and 1/2 kilogram charge.  Because of the reduced diameter, the activating pressure was about twice the figure for Type I.  It is understood that this smaller type was not produced in any quantity.

Next Time: French Bombs

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