BULLET CARTRIDGE, METHOD FOR MANUFACTURING A BULLET CARTRIDGE AND PLANT FOR MANUFACTURING BULLET CARTRIDGES

Abstract

In a bullet cartridge (1) comprising a bullet case (3) defining a caliber diameter (D), a projectile (4) inserted into the neck portion (31) of the bullet case (3), and at least one annular layer (51, 52) of a sealing medium (5) formed from a sealing medium (5) between the bullet case (3) and the projectile (4), it is provided that the annular layer (51, 52) is applied by means of microdosing and/or comprises not more than 1 mg of sealing medium (5) per mm of caliber diameter (D).

Claims

1. A bullet cartridge (1) comprising a bullet case (3) defining a caliber diameter (D), a projectile (4) inserted into the neck portion (31) of the bullet case (3), and at least one annular layer (51, 52) of a sealing medium (5) formed from a sealing medium (5) between the bullet case (3) and the projectile (4), characterized in that the annular layer (51, 52) is applied by means of microdosing and/or comprises not more than 1 mg of sealing medium (5) per mm of caliber diameter (D), in particular not more than 0.5 mg of sealing medium (5) per mm of caliber diameter (D), preferably not more than 0.3 mg of sealing medium (5) per mm of caliber diameter (D).

2. Bullet cartridge (1) according to claim 1, characterized in that the sealing medium (5) of the at least one annular layer (51, 52) is uniformly distributed in the circumferential direction, in particular the at least one annular layer (51, 52) having deviations of not more than 50 nL/mm annular circumferential width, in particular not more than 5 nL/mm annular circumferential width, preferably not more than 5 nL/mm annular circumferential width.

3. Bullet cartridge (1) according to claim 1 or 2, characterized in that the at least one annular layer (51, 52) has a width of at least 1 mm, in particular at least 2 mm, and/or not more than 10 mm, in particular not more than 6 mm.

4. Bullet cartridge (1) according to one of the preceding claims, characterized in that the at least one annular layer (51, 52) has a thickness of at least 0,003 mm, in particular at least 0,005 mm, and/or not more than 0.04 mm, in particular not more than 0,015 mm.

5. Bullet cartridge (1) according to one of the preceding claims, characterized in that the at least one annular layer (51, 52) is formed from multiple drops.

6. Bullet cartridge (1) according to any one of the preceding claims, characterized in that the bullet cartridge (1) comprises not more than one annular layer (51) of the sealing medium.

7. Bullet cartridge (1) according to one of the preceding claims, wherein the sealing medium (5) comprises 50 vol-% to 70 vol-% of a sealant mixture, in particular containing bitumen, in particular 54 vol-% to 65 vol-% of a sealant mixture, in particular containing bitumen, and 5 vol-% to 20 vol-% thinner, in particular 6.5 vol-% to 16.5 vol-% thinner, and 25 vol-% to 40 vol-% graphite (D90<10 ?m), in particular 28.5 vol-% to 32 vol-% graphite (D90<10 ?m), in particular consists thereof.

8. Method of manufacturing a bullet cartridge (1), wherein a bullet case is provided which has a neck portion for receiving a projectile, which neck portion defines an inner circumference, wherein an annular, preferably full circumferential, layer (51, 52) of a sealing medium (5), in particular a bitumen-containing sealant mixture, is applied to the bullet case (3) at an inner circumference (33) in the neck portion (31) of the bullet case (3), characterized in that a predetermined amount of the applied sealing medium (5) is provided by microdosing (7).

9. Method according to claim 8, characterized in that the bullet cartridge (1) is manufactured with a certain caliber diameter (D) and that for forming the annular layer (51, 52) in relation to the caliber diameter (D) of the bullet cartridge (1) a predetermined amount of not more than 1 mg of sealing medium (5) per mm of caliber diameter (D), in particular not more than 0.5 mg of sealing medium (5) per mm of caliber diameter (D), preferably not more than 0.3 mg of sealing medium (5) per mm of caliber diameter (D) is applied.

10. Method according to claim 8 or 9, characterized in that for forming the annular layer (51, 52) in relation to the caliber diameter (D) of the bullet cartridge (1) a predetermined amount of not less than 0.01 mg sealing medium (5) per mm caliber diameter (D), in particular not less than 0.03 mg sealing medium (5) per mm caliber diameter (D), preferably not less than 0.05 mg sealing medium (5) per mm caliber diameter (D) is applied.

11. Method according to one of claims 8 to 10, characterized in that a bitumen-containing sealant mixture is provided as the sealing medium (5), wherein the sealing medium, in particular in the microdosing, is guided at a temperature of at least 25? C., in particular at least 30? C., preferably at least 35? C., and/or at most 60? C., in particular at most 55? C., preferably at most 50? C., particularly preferably at most 45? C.

12. Method according to one of claims 8 to 11, characterized in that the sealing medium, in particular in the microdosing, is adjusted to a viscosity in the range from about 5 s to 100 s, in particular 10 s to 70 s, preferably in a range from 30 s to 70 s or in a range from 10 s to 20 s, wherein in particular the viscosity is adjusted according to a viscosity measurement method according to DIN 53211 using an ISO-4 mm-dip-flow cup.

13. Method according to claim 12, characterized in that the sealing medium (5) is dispensed from the microdosing (7) in mist form (57), wherein in particular the viscosity of the sealing medium in the microdosing (7) is set to at most 30 s, in particular at most 25 s, preferably at most 20 s.

14. Method according to claim 12, characterized in that the sealing medium (5) is dispensed from the microdosing (7) in droplet form, wherein in particular the viscosity of the sealing medium (5) in the microdosing unit (7) is set to at least 10 s, in particular at least 15 s, preferably at least 30 s.

15. Method according to one of the claims 8 to 14, characterized in that for forming the annular layer (51, 52) the sealing medium (5) is dispensed from the microdosing (7) in at least one, preferably multiple, drops (55), wherein in particular the bullet cartridge (1) is produced with a certain caliber diameter (D) and that for forming the annular layer (51, 52) in relation to the caliber diameter (D) of the projectile cartridge (1), 1 to 5 drops (55) are dispensed per mm of caliber diameter (D) and/or in that an annular layer (51, 52) is formed with a width of at least 1 mm, in particular at least 2 mm, and/or not more than 10 mm, in particular not more than 6 mm, and/or with a thickness of at least 0,003 mm, in particular at least 0,005 mm, and/or not more than 0,025 mm, in particular not more than 0,015 mm.

16. Method according to claim 14 or 15, characterized in that the drops (55) are dispensed at a rate in the range from 100 Hz to 3000 Hz, in particular in the range from 250 Hz to 2000 Hz, preferably in the range from 300 Hz to 1000 Hz.

17. Method according to any one of claims 8 to 16, characterized in that the neck portion (31) of the bullet case (3) is radially widened before insertion of the projectile (4), in particular along an edge of a confluence 30.

18. Method according to any one of claims 8 to 17, characterized in that the sealing medium (5) is dispensed from the microdosing (7) through a nozzle (71) which is preferably held orthogonally to the inner circumference (33) and/or at a predetermined distance of at least 0.5 mm, in particular at least 1 mm, and/or not more than 20 mm, in particular not more than 10 mm, preferably not more than 5 mm.

19. Method according to claim 18, characterized in that, before the sealing medium (5) is dispensed, a movement, in particular a linear movement, is performed for inserting the nozzle (71) into the neck portion (31) of the bullet case (3).

20. Method according to claim 17 or 19, characterized in that a nozzle (71) with an initial diameter in the range from 0.05 mm to 0.5 mm, in particular in the range from 0.1 mm to 0.3 mm, preferably with an initial diameter of 0.15 mm, is used.

21. Method according to any one of claims 8 to 20, characterized in that the bullet case (3) is rotated in relation to the microdosing (7), in particular the nozzle (71), about a symmetry axis (S) of the bullet case (3), preferably continuously.

22. Method according to any one of claims 8 to 21, characterized in that the sealing medium (5) comprising 50 vol-% to 70 vol-% of a sealant mixture, in particular containing bitumen, in particular 54 vol-% to 65 vol-% of a sealant mixture, in particular containing bitumen, and 5 vol-% to 20 vol-% thinner, in particular 6.5 vol-% to 16.5 vol-% thinner, and 25 vol-% to 40 vol-% graphite (D90<10 ?m), in particular 28.5 vol-% to 32 vol-% graphite (D90<10 ?m), in particular consisting thereof, is provided.

23. A plant for manufacturing bullet cartridges (1), particularly adapted and arranged to perform a method according to any one of the preceding claims, comprising a bearing for holding a bullet case having a neck portion for receiving a projectile defining an inner circumference, characterized by a microdosing for providing a predetermined amount of a sealing medium (5) for application to the inner circumference.

24. Plant according to claim 23, characterized by at least one heater and/or cooler and, optionally, a temperature control comprising a temperature sensor for guiding the sealing medium, in particular in the microdosing, preferably at a temperature of at least 25? C. and/or at most 60? C.

25. Plant according to claim 23 or 24, characterized by at least one, in particular exactly one, nozzle (71) fluidically connected to the microdosing and having an outlet diameter in the range from 0.05 mm to 0.5 mm, in particular in the range from 0.1 mm to 3 mm, for dispensing the sealing medium (5).

26. Plant according to claim 25, characterized in that the nozzle (71) and the bearing are matched to one another in such a way that the nozzle is aligned orthogonally to the inner circumference (33) when the sealing medium (5) is dispensed.

27. Plant according to claim 25 or 26, characterized in that the nozzle (71) and the bearing are matched to one another in such a way that the nozzle (71) is kept at a predetermined distance of at least 0.5 mm, in particular at least 1 mm, and/or not more than 20 mm, in particular not more than 10 mm, preferably not more than 5 mm, from the inner circumference (33) when dispensing the sealing medium.

28. Plant according to any one of claims 25 to 27, characterized in that the nozzle (71) and the bearing of the nozzle for moving the nozzle (71) relative to the inner circumference, in particular for inserting the nozzle (71) into the neck portion (31) of the bullet case (3), are linearly movable relative to one another.

29. Plant according to one of claims 23 to 28, characterized in that the bearing is matched to the microdosing and/or the nozzle in such a way that the bullet case (3) can be rotated about a symmetry axis (S) of the bullet case (3), preferably continuously.

30. Plant according to any one of claims 23 to 29, characterized by at least one conveyor for feeding and/or discharging at least one bullet case per second, in particular at least two bullet cases per second, preferably at least three bullet cases per second, to and from the microdosing.

Description

[0048] Further features, advantages and characteristics of the invention will become apparent from the following description of preferred embodiments of the invention with reference to the accompanying drawings, in which show:

[0049] FIG. 1a a schematic sectional view of a bullet cartridge;

[0050] FIG. 2a a schematic representation of a method in which a first annular layer of sealing medium is applied to a bullet case;

[0051] FIG. 2 a schematic representation of a method in which a second annular sealing medium layer is applied;

[0052] FIG. 3a a schematic representation of another method in which a first annular sealing-medium-layer is applied to a bullet case;

[0053] FIG. 3b a schematic representation of the application of a second sealing-medium-layer according to the other method; and

[0054] FIG. 4a a schematic sectional view of a bullet case with two annular sealing-medium-layers arranged in the neck portion and a separate projectile.

[0055] For ease of reading, the same or similar reference signs are used for the same or similar components in the following description of the invention based on the illustrated preferred embodiments.

[0056] A bullet cartridge is generally designated by the reference sign 1. The bullet cartridge 1 comprises as essential components a bullet case 3, a projectile 4 and a sealing medium 5 provided between the projectile 4 and the bullet case 3.

[0057] FIG. 1 shows a schematic cross-sectional view of a bullet cartridge 1. The sealing medium 5 creates a seal between the projectile 4 and the case 3. The bullet case 3 is a rotational body with a symmetry axis S. The bullet cartridge 1 has a certain caliber diameter D, which can be determined on the basis of the inner diameter at the inner circumference 33 in the neck portion 31 of the case 3. Typical caliber diameters D are, for example, 5.56 mm, 7.62 mm or 8.6 mm. The neck portion 31 designates the section of the case 3 into which the projectile 4 is inserted to form the bullet cartridge 1. In the case of the bullet case 3 shown in FIGS. 1 and 4, the neck portion 31 has a narrower diameter than a region 39, located behind it with respect to the confluence 30 of the case 3, for receiving the propellant charge.

[0058] Two annular layers 51, 52 of the sealing medium are applied to the inner circumference 33 of the case 3 in its neck portion 31. A first layer 51, arranged closer to the free edge of the case 3, contains a bitumen-containing sealing lacquer mixed with an additive as sealing medium 5. The sealing medium for forming the first layer 51 may, for example, comprise 42 wt.-% of a bitumen-containing sealing lacquer, 42 wt.-% of thinner and 16 wt.-% of graphite. An optional second layer 52, arranged deeper in the case, contains a bitumen-containing sealing lacquer without additive. The second layer 52 contains 66 wt % of a bituminous sealing lacquer and 34 wt % of thinner. The same or a different mixture may be used for an embodiment with only one annular layer 51. Alternatively, in particular for an embodiment with only one annular layer 51, the sealing medium may comprise 50 vol-% to 70 vol-% of a bitumen-containing sealing lacquer, especially 54 vol-% to 65 vol-% of a bitumen-containing sealing lacquer, and 5 vol-% to 20 vol-% thinner, in particular 6.5 vol-% to 16.5 vol-% thinner, and 25 vol-% to 40 vol-% of graphite (D90<10 ?m), in particular 28.5 vol-% to 32 vol-% graphite (D90<10 ?m). The width of the first and/or second layer 51, 52 parallel to the direction of the symmetry axis S of the bullet case 3 is in the range of 0.5 mm to 6 mm each, in particular in the range of 1 mm to 3 mm each. The thickness of the first and/or second layer 51, 52 radial to the direction of the symmetry axis S of the bullet case 3 is in the range of 0.003 mm to 0.04 mm, in particular in the range of 0.005 mm to 0.015 mm. The distance between two layers 51, 52 can be less than 2 mm, in particular less than 1.5 mm.

[0059] FIGS. 2a and 2b schematically show a first method for applying annular layers 51 and 52 of sealing medium 5 to the inner circumference 33 of the bullet case 3. The sealing medium 5 is applied to the inner circumference 33 of the bullet case 3 in the neck portion 31 of the bullet case 3 by means of microdosing 7. With the aid of the microdosing 7, the sealing medium 5 is applied particularly uniformly to the inner circumference. The microdosing 7 is held completely outside the bullet case 3, in front of its confluence 30. The bullet case 3 is rotated about its symmetry axis S in relation to the microdosing 7.

[0060] In the embodiment shown in FIG. 2a, the sealing medium 5 is applied to the inner circumference 33 in the form of drops 55 from the microdosing 7. By means of microdosing 7, multiple defined individual spots of sealing medium 5 are applied along the inner circumference 33 of the case 3, which together form a circumferential and homogeneous coating ring. In relation to the caliber diameter D of the bullet case 3, the microdosing 7 dispenses one to five drops, which may also be referred to as shots, per mm of caliber diameter D. For example, with a 5.56 mm caliber diameter, 6 to 28 shots can be dispensed. With a 7.62 mm caliber diameter, 8 to 38 shots can be dispensed. With an 8.6 mm caliber diameter, 9 to 42 shots can be fired.

[0061] The microdosing 7 has a nozzle 71 with an opening diameter in the range from 0.1 mm to 0.3 mm at its discharge end directed towards the bullet case 3. The nozzle 71 is adapted and arranged to dispense the sealing medium 5 in a certain firing direction or dispensing direction A. The dispensing direction A is oriented at an inclined angle with respect to the symmetry axis S. The dispensing direction A may cross the symmetry axis S. The inclined angle between the dispensing direction A and the symmetry axis S can be in the range of 30? to 90?, for example. Preferably, the oblique angle is at least 45?, in particular at least 60?. The nozzle 71 of the microdosing 7 is kept at a distance from the inner circumference 33 of the bullet case 3 in the dispensing direction A. The individual drops 55 of the sealing medium 5 are then not simultaneously in contact with both the nozzle 71 and the inner circumference 33.

[0062] As shown in FIG. 2b, the annular sealing-medium-layer 51, which is closer to the confluence 30, is produced first, followed by the second layer 52 of sealing medium 5, which is more distant with respect to the confluence 30. Alternatively, in reverse order, the second layer 52 can be produced first and then the first layer 51.

[0063] For example, a bitumen-containing mixture can be used as the sealing medium 5. The sealing medium 5 may comprise a bitumen-containing sealant mixture, such as a sealing lacquer, and a thinner, and optionally an additive, such as graphite. For application by means of microdosing 7, the viscosity of the bitumen-containing mixture can be adjusted in a range from 10 s to 70 s. The viscosity of the sealing medium 5 can be determined by the viscosity measurement method according to DIN 52211 using a 4 mm-ISO-dip-flow cup.

[0064] It has been found to be advantageous if the microdosing 7 is provided with a heater and/or cooler 73 for controlled adjustment of the temperature of the sealing medium 5. With a heater and/or cooler 73, the temperature of the sealing medium 5, while it is conveyed through the microdosing 7, can be guided in a temperature range between, for example, 30? C. and 55? C. The heater and/or cooler 73 may be adapted and arranged to impose a controlled temperature on the complete microdosing 7. Alternatively, the heater and/or cooler 73 can be adapted and arranged to regulate the temperature of different portiones of the microdosing 7 independently of one another.

[0065] For example, a microdosing valve in the form of a solenoid valve from Fritz-Gyger AG can be used as microdosing 7, in particular valve type: SMLD 300G (sub-micro liquid dispenser). The microdosing valve can, for example, be an electromagnetically actuated, so-called solenoid valve. The sealing medium 5 flows directly through the microdosing valve. In the de-energized state, the microdosing valve is closed. A closing spring of the microdosing valve acts on a mobile armature with a valve ball. When the valve coil is energized, the mobile armature with the valve ball is magnetically attracted by the magnetic field of a stationary armature, so that the microvalve opens and the sealing medium, which is under a pressure of, for example, 1 to 5 bar dispenses from the valve nozzle 71. The microdosing valve comprises a built-in heater 73 for adjusting the temperature of the sealing medium 5. The microdosing valve preferably comprises a hard-sealing valve, which is preferably adapted and arranged to ensure an opening lift of a few hundredths of a mm in a precisely reproducible manner. The microdosing valve can be arranged for a cycle rate of up to 4000 Hz. Hard materials, such as sapphire and/or ruby, may be provided for the valve seat and/or the valve ball. The microdosing valve is preferably adapted and arranged to reproducibly dispense individual shots or drops in the nanoliter range.

[0066] Alternatively, a microdosing valve in the form of a piezo valve from the company VERMES Microdispensing, in particular valve type MDV 3280, can be used as microdosing 7. The microdosing valve is preferably adapted and arranged for reproducibly dispensing individual shots or drops in the nanoliter range. The piezo valve can be adapted and arranged to be placed under voltage by a control unit for dosage of a sealing medium 5. The voltage pulses applied to the piezo valve by the control unit open and/or close the piezo valve. The piezo valve may comprise a plunger for closing the nozzle 71. The plunger may be connected to a piezostack of the piezo valve by means of a lever device. By moving the piezo stack up and down, drops or shots can be precisely dispensed at a frequency of several 100 Hz.

[0067] FIGS. 3a and 3b show a second method for producing layers 51, 52 from sealing medium 5 on the inner circumference 33 of a bullet case 3. The method differs substantially only from that previously described in that the nozzle 71 of the microdosing 7 is oriented in a substantially orthogonal dispensing direction A with respect to the inner circumference 33. The nozzle 71 is inserted into the bullet case 3 through the confluence 30 for application of the sealing medium 5. For this purpose, the nozzle 71 can be moved linearly into the bullet case parallel to the direction of the symmetry axis S. The nozzle 71 has a curvature 72 in the area just before its dispensing opening, which defines the dispensing direction A. After the sealing medium has been applied, the nozzle 71 is removed again from the neck portion 31 of the bullet case 3, for example, with a reverse movement.

[0068] As shown in FIG. 3b, the annular sealing medium layer 52, which is further away from the confluence 30, is produced first, followed by the sealing medium layer 51, which is closer to the confluence 30.

[0069] In the two methods illustrated in FIGS. 2a and 3a, respectively, the sealing medium 5 may be dispensed in the form of drops 55 or in the form of a spray mist 57. In order to dispense a spray mist 57, it may be preferred to set the viscosity of the sealing medium 5 to not more than 20 s. This allows a spray mist 57 to be applied to the case 3 from the microdosing 7. The spray mist 57 can be used to apply a particularly thin sealing medium layer 51, 52.

[0070] After the application of the single layer or, optionally, the two layers 51 as well as 52, as indicated in FIG. 3, the projectile 4 is inserted into the neck portion 31 of the case 3 to form the bullet cartridge 1 shown in FIG. 1.

[0071] The features disclosed in the foregoing description, figures, and claims may be significant to the various embodiments of the invention both individually and in any combination.

LIST OF REFERENCE SIGNS

[0072] 1 bullet cartridge [0073] 3 bullet case [0074] 4 projectile [0075] 5 sealing medium [0076] 7 microdosing [0077] 30 confluence [0078] 31 neck portion [0079] 33 inner circumference [0080] 39 range [0081] 51,52 annular layer [0082] 55, 57 drop or spray mist [0083] 71 Nozzle [0084] 72 Curvature [0085] 73 Heater and/or cooler [0086] A dispensing direction [0087] D caliber diameter [0088] S symmetry axis