EP3091329B1 - Method for producing a load for an explosive projectile - Google Patents

Description

The invention relates to a method for producing a charge for an explosive projectile.

According to the state of the art, plastic-bound explosive charges are generally used for the production of large-caliber explosive projectiles. Such explosive charges have the disadvantage that they have a relatively large thermal expansion coefficient. As a result, it may happen that such an explosive charge contracts more strongly than a surrounding projectile casing, especially at low temperatures. The explosive charge is then undesirably loose in the projectile casing.

To overcome this disadvantage, it is from the EP 1 338 860 A2 known to introduce through a mouth hole of the projectile casing a plastic envelope, which is subsequently inflated with air and thus forced against an inner wall of the projectile casing. Subsequently, a pourable plastic-bound explosive charge is introduced through the mouth hole into the projectile casing which is lined with the plastic casing. After polymerizing the plastic-bound explosive charge, the mouth hole is closed, for example, by screwing in a detonator.

The EP 2 435 780 B1 discloses a method for producing a large caliber explosive projectile. The projectile shell is made as a two-part shell. Before connecting the two projectile casing sections, a casing adapted to its inner contour and made of an elastic material is introduced into at least one of the two projectile casing sections. Subsequently, the plastic-bound explosive charge is poured into the shell. Finally, the bullet casing sections are bolted together.

The DE 10 2005 050 973 A1 discloses an explosive projectile in which a projectile shell is provided in partial areas of its inner surface with a silicone layer. Thus, a voltage is exerted on the explosive charge received in the projectile casing, so that the explosive charge is always frictionally held in the projectile casing. US 5,959,237 A. is the closest prior art and discloses a method of manufacturing a charge comprising the steps of: preparing a plastic-bonded explosive molding; at least partially enveloping a peripheral surface of the explosive molded part with a shrink tube so that at least a first shrink tube end of the shrink tube extends over a first mold part end of the explosive mold part; Heating the shrink tube to a predetermined shrinkage temperature, wherein the diameter thereof is reduced, so that the shrink tube wrinkle-free applies to the peripheral surface of the explosive molding.

The object of the invention is to provide an alternative method for producing a charge for an explosive projectile.

This object is solved by the features of patent claim 1. Advantageous embodiments of the invention will become apparent from the features of claims 2 to 9.

• Herstellen eines kunststoffgebundenen Sprengstoffformteils;
• zumindest abschnittsweises Umhüllen einer Umfangsfläche des Sprengstoffformteils mit einem Schrumpfschlauch, so dass zumindest ein erstes Schrumpfschlauchende des Schrumpfschlauchs sich über ein erstes Formteilende des Sprengstoffformteils hinweg erstreckt;
• Erzeugen einer axialen Zugspannung auf den Schrumpfschlauch; und
• Erwärmen des Schrumpfschlauchs auf eine vorgegebene Schrumpftemperatur, wobei sich dessen Durchmesser verkleinert und gleichzeitig dessen Länge vergrößert, so dass sich der Schrumpfschlauch faltenfrei an die Umfangsfläche des Sprengstoffformteils anlegt.

According to the invention, a method for producing a charge for a projectile is proposed, which comprises the following steps:

• Producing a plastic-bonded explosive molding;
• at least partially enveloping a peripheral surface of the explosive molded part with a shrink tube so that at least a first shrink tube end of the shrink tube extends beyond a first mold part end of the explosive mold part;
• Generating an axial tensile stress on the shrink tubing; and
• Heating the shrink tube to a predetermined shrinkage temperature, wherein the diameter is reduced and at the same time increases its length, so that the shrink tube rests wrinkle-free on the peripheral surface of the explosive molding.

In departure from the prior art, the projectile casing is not filled with a liquid explosive in the method according to the invention, which then hardens. It is first prepared according to the invention a plastic-bound explosive molding. The explosive is a conventional insensitive, plastic-bound explosive.

In a further method step, a circumferential surface of the explosive molding is at least partially enveloped by a shrink tube so that at least a first shrink tube end of the shrink tube extends over a first mold part end of the explosive molding. A diameter of the shrink tube is chosen so that it is insignificantly larger than another diameter of the example rotationally symmetrical shaped explosive molding. The diameter of the heat-shrinkable tube and the further diameter of the explosive molding are matched to one another in such a way that the heat-shrinkable tube reliably and reliably abuts against the peripheral surface of the explosive molding during the shrinking process.

After a further process step of the invention, an axial tensile stress is applied to the shrink tube. Ie. the shrink tube is claimed in its longitudinal direction to train. In a further method step, the shrink tube is heated to a predetermined shrinking temperature. This reduces its diameter and at the same time increases its length, so that the shrink tube applies wrinkle-free to the peripheral surface of the explosive molding.

The proposed method is universal and is particularly suitable for wrapping an explosive molding whose peripheral surface is at least partially conical. In particular, by the step of generating an axial tensile stress on the shrink tube is achieved that the shrink tube applies wrinkle-free in the region of a small diameter of a conical explosive molding on the peripheral surface.

The inventive method provides a semi-finished product consisting of an explosive molding and an elastic plastic sheath. The proposed semi-finished product can be readily inserted into a projectile casing. It is no longer necessary to line the projectile casing with a plastic wrapper prior to loading. The envelope proposed according to the invention is advantageously designed so that the differences in the coefficients of thermal expansion between the projectile casing and the load can be compensated. For this purpose, several heat shrink tubing can be successively applied to the explosive molding.

According to an advantageous embodiment of the invention, a second Schrumpfschlauchende is fixed relative to the explosive mold part for generating the axial tensile stress and exerted on the first shrink tube end the tension. For fixing the second shrink tube end relative to the explosive molding, the second shrink tube end can be clamped by means of a hose clamp or a suitable clamping device against the peripheral surface of the explosive molding. The first shrink tube end can be gripped with a further clamping device and subjected to a tensile stress. The proposed embodiment leads to an explosive molding, which is wrapped only in sections with a shrink tube.

According to an alternative embodiment, the second shrink tubing end extends beyond a second mold part end of the explosive mold part. Ie. the explosive molding is completely absorbed in the shrink tube in this case. Subsequently, a tensile stress can be exerted both on the first and on the second heat shrink tubing end. Before heating both heat shrink tube ends can also be sealed liquid-tight. Both the generation of a tensile stress and the liquid-tight closing of the heat shrink tube ends can be done with a clamping device with which the respective heat shrink tube ends gripped while clamped and sealed liquid-tight and simultaneously placed under a tensile stress.

The tensile stress exerted on the shrink tubing can be generated by loading the first shrink tubing end in the axial direction with a weight force of 0.1 to 100 N, preferably 0.5 to 50 N. Preferably, the weight provided by the explosive molding is used to generate the tensile stress.

To heat the shrink tubing, water, oil or air can be used. The particular heat transfer medium used is heated to the predetermined shrinking temperature. The predetermined shrinking temperature is 80 ° C to 110 ° C, preferably 85 ° C to 100 ° C. A loading of the explosive molding with the aforementioned shrinking temperature is harmless.

According to a further embodiment feature, after the shrinking process, the shrink tubing ends extending beyond the mold part ends cut off. Thus, the production of the semifinished product according to the invention is complete.

The explosive molding may be substantially rotationally symmetrical, wherein one of the two mold part ends has a larger diameter than the other mold part end. Ie. the explosive molding may be at least partially conical or conical.

For the purposes of the present invention, a "charge" for an explosive projectile can be formed from a plurality of semi-finished products produced by the process according to the invention. The charge may also comprise an explosive molding, which is not provided with a sheath.

The semi-finished products according to the invention can readily be used for filling a projectile casing. Preferably, the two ends of the charge are produced from semi-finished products according to the invention, whereas a middle part of the charge is formed from an explosive molding which is not covered with a plastic layer.

The invention will be explained in more detail with reference to the drawing.

In the single figure, the process steps for producing a semifinished product according to the invention are shown schematically. In method step a), a molten plastic-bonded insensitive explosive mass 2 is poured into a mold 1. After the explosive composition has hardened, an explosive molding 3 formed therefrom is removed from the mold (see method step b)).

The explosive molding 3 is wrapped in process step c) with a shrink tube 4. The explosive molding 3 is formed substantially rotationally symmetrical. It has a maximum diameter D _max and a minimum diameter D _min . A diameter D _{S of} the shrink tube 4 is selected relative to the maximum diameter D _max so that the explosive mold part 3 can be freely inserted into the shrink tube 4. The diameter D _{S of} the shrink tube 4 is relative to the diameters D _max and D _min also chosen so that during shrinking the shrink tube 4 largely wrinkle-free on a peripheral surface U of the explosive molding 3 applies.

In method step d), a first shrink tube end E1 and a second shrink tube end E2 are each clamped in a clamping device 5 such that the shrink tube 4 is closed in a liquid-tight manner. By means of the clamping device 5, an axial stress S can be exerted on the shrink tubing 4. At the same time the shrink tube 4 is washed with water 6, which has, for example, a temperature of 95 ° C. As a result, the shrink tubing 4 shrinks and wrinkles on the peripheral surface U on. This is especially true for that portion of the plastic molding 3, which has the minimum diameter D _min .

In a variant of method step d), which is not shown in the figure, the two shrink tube ends E1 and E2 are also closed in a liquid-tight manner with a clamping device 5, for example a clamp. Then, the plastic molded part 3 is hung in a water bath that its minimum diameter D _min has upwards. A tensile stress S is generated in this case solely by the weight of the plastic molded part 3.

Finally, in method step f), the first shrink tube end E1 and the second shrink tube end E2 are cut as far as they protrude beyond a first mold part end F1 and a second mold part end F2. The explosive molded part 3 thus produced is enveloped on its peripheral surface U substantially form-fitting manner by the shrink tubing 4. A semifinished product according to the invention can form a charge for an explosive projectile. The charge can also be formed from a plurality of semifinished products according to the invention or a combination of one or more semifinished products according to the invention with one or more explosive moldings 3 which are not surrounded by a heat-shrinkable tube 4.

To produce the explosive projectile, a corresponding charge is introduced into a projectile casing and subsequently sealed in such a way that the charge is held in the projectile casing under a prestress provided by the heat-shrinkable tube 4. This can be safely and reliably avoided unwanted loose absorption of the charge due to different thermal expansion coefficients of the projectile casing and the charge.

LIST OF REFERENCE NUMBERS

1

shape

2

explosive mass

3

Explosives molding

4

shrinkable tubing

5

clamping device

6

water

D _max

maximum diameter

D _min

minimum diameter

D _S

Diameter of the shrink tube

E1

first shrink tubing end

E2

second shrink tubing end

F1

first molding end

F2

second molding end

S

tension

U

peripheral surface

Claims (9)

1. Method for producing a charge for an explosive projectile, comprising the following steps:

   producing a plastic-bonded explosive moulding (3);

   placing a shrink tube (4) around at least some of a circumferential surface (U) of the explosive moulding (13), so that at least a first shrink tube end (E1) of the shrink tube (4) extends beyond a first moulding end (F1) of the explosive moulding (3) ;

   generating an axial tensile stress (S) on the shrink tube (4); and

   heating the shrink tube (4) to a prescribed shrink temperature, the diameter (D_S) thereof decreasing and at the same time the length thereof increasing, so that the shrink tube (4) comes to lie against the circumferential surface (U) of the explosive moulding (3) without any creases.
2. Method according to Claim 1,
   wherein, to generate the axial tensile stress (S), a second shrink tube end (E2) is fixed in relation to the explosive moulding (3) and the tensile stress (S) is exerted on the first shrink tube end (E1).
3. Method according to one of the preceding claims, wherein the second shrink tube end (E2) extends beyond a second moulding end (F2) of the explosive moulding (3).
4. Method according to one of the preceding claims, wherein a tensile stress (S) is exerted both on the first shrink tube end (E1) and on the second shrink tube end (E2).
5. Method according to one of the preceding claims, wherein the two shrink tube ends (E1, E2) are sealed liquid-tight before the heating.
6. Method according to one of the preceding claims, wherein water, oil or air is used for heating the shrink tube (4).
7. Method according to one of the preceding claims, wherein the prescribed shrinking temperature is 80°C to 110°C, preferably 85°C to 100°C.
8. Method according to one of the preceding claims, wherein the shrink tube ends (E1, E2) extending beyond the moulding ends (F1, F2) are cut off after the shrinking operation.
9. Method according to one of the preceding claims, wherein the explosive moulding (3) has a substantially rotationally symmetrically designed form, in which one of the two moulding ends (F1, F2) has a greater diameter (D_max) than the other moulding end (F1, F2).

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