Monday 17 August 2020

German Explosive Ordnance - German Mines and Grenades (Part 2)

  







German Explosives






Wooden Box Mine 42 (Holzmine) (A/T)


Length: 13 inches
Diameter/Width: 12 inches
Depth: 4 and 1/2 inches
Total Weight: 18 pounds

Explosive: Amatol 50/50
Explosive Weight: 11 and 1/2 pounds
Material: Wood
Pull or Pressure required: 200 to 400 pounds

Color: Gray with red band on one end.


Description: The mine consists of a compartmented wooden box which contains the explosive charge.  As shown in the cutaway drawing, a Z.Z. 42 igniter, which rests on a supporting block, projects into the explosive charge.  A pressure block, immediately above the igniter, is supported by a shear flange which is secured to the outer wall of the box by wooden dowel pins.


Operation: A pressure of 200 pounds of more on the pressure block shears the dowels.  Shear flange, forced down, pushes out the pin in the Z.Z. 42.  The freed striker, driven by spring, sets off a percussion cap-detonator-booster-main charge.


Markings:
German
V.B.Mi.1
bestehend sus: 26 Sprengkorpern ohne Bohrung
1 Sprengkorper mit Bohrung
Verpackt, H. Ma. Bg 28643 E1942'3
Zugehorige Zundungen in besonderem Packgefass

Translated
V.B.Mi.1
consisting of: 26 1928 pattern 200gm charges without igniter sockets
1 1928 200gm charge with igniter socket
Packed H. Ma. Bg 28643 E1942'3
Igniter assembly packed separately.





Spreng Riegel, 8-kg (A/T)


Length: 33 inches
Depth: 3.25 inches
Explosive Weight: 17.6 pounds

Color: Dull Black
Material: Steel
Pull or Pressure required: 880 pounds center; 440 pounds end.


Description: The mine consists of two main components, the tray, and the charge.

Tray: This is of sheet metal and carries a horizontal rib slightly above the shear wire holes.  On its underside is the word UNTEN (bottom).  Two shear wires pass through the holes in the sides of the sheet 4 inches from each end.  Holes 3/16 inch in diameter are located approximately 1 and 1 and 2/5 inches from each end and can be closed by small shutters on the outside of the tray.  At the ends of the tray are flanges, of which one is solid while the other carries a central slot to permit insertion of the stirrup of the Z.Z. 42 actuating pin.  On the outside of the tray at each end is a rotatable arrow which can be sent to SICHER (safe) or SCHARF in a counterclockwise direction (viewed from the outside)  Rotation of the arrow will rotate the disc in a clockwise direction (viewed form the inside) and lift the arm into a horizontal position, where it is locked by the spring-loaded catch.  In this position the Z.Z. 42 igniters bear against the flange of the arm and will function if the charge is depressed.  The only method by which the catch can be withdrawn, allowing the arm to be lowered and disarming the mine, is by inserting a pin upwards through a small hole, 1.8 inches in diameter, in the base of the tray about 3/16 inch from its end.  This forces upwards the arm of an angle-shaped piece; the other arm of this piece engages in the end of the catch and withdraws it.

Charge: This is encased in a metal container which is provided with four igniter sockets - two end sockets for the main Z.Z. 42 igniters, as in the standard R-Mine 43, and two subsidiary sockets, also in the ends of the charge near the top left-hand corner when the charge is viewed end-on.  These last two sockets are normally kept closed by screw plugs.


Operation: The mine will fire under a pressure of 440 pounds at the ends or a pressure of 880 pounds in the center.  When these pressures are applied, one of both shear wires are sheared and the charge falls into the tray.  As the charge falls, the detent pin is pushed out of one of both of the igniters by the shoulders of the actuating plate thus firing the mine.


Remarks: Principal differences between the Riegel Mine 8 kg and the Riegel Mine 43 are listed below:

1. There is no lid, the mine consisting of charge and tray only.
2. There is no spring-loaded shutter arrangement.
3.The arming device permits the mine to be transported in an unarmed state.
4. There are auxiliary igniter sockets at the ends of the charge, but none in the top or sides.
5. The shutters for closing the safety bar holes are on the outside of the tray and are not spring-loaded.
6. There is no reinforcing bar on the charge where it rests on the shear wire, nor is the tray lines inside to insure a neat shearing.  Thus, in the specimen found, the shear wires had suffered noticeable sagging without being sheared.







Heavy Anti-Tank


Length: 17 inches
Diameter/Width: 15 and ¾ inches
Depth: 10 and 1/2 inches
Total Weight: 300 pounds
Explosive: TNT
Explosive Weight: 37 pounds
Material: Cast Iron
Pull or Pressure required: Varied


Description: This mine is rectangular in shape, and its case and many of its component parts are made of cast iron.  It consists of a box, a cover plate, a removable plug, and one or more firing mechanisms.

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 anchoring it in place by either bolts or stirrups.  A centrally located hole is also provided, to take the standard pull igniter Z.Z. 35 for the purpose of connecting an additional explosive 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 rectangular 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 surface.  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 provided 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 pressure of 100 pounds on the pedal may fire the mine.  However, the exact construction is not clear.  The pedal may also be 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 recess 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.


4. Firing Mechanism: The firing mechanism consists of the following:

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 and 3/4 inches in diameter.  When pressure is applied to the cover plate, the head of the igniter is depressed 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 igniter 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 provided with a loop to which the wire 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 igniter.  The igniter fires the detonator and booster, which in turn explodes the main charge.  Even if the locking pin is removed, care must be exercised not to lift the cover quickly, 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 interconnected 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 degrees 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 vehicles, 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 fired 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 period of time.  The length of time required to lay the mines prevents their effective use in fast moving warfare.




Next Time: German Mines and Grenades (Part 3)


Source: German Explosive Ordnance Vol. 1: Bombs, Rockets, Grenades, Mines, Fuzes & Igniters

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