TRACKING

TECHNICAL FIELD

The present invention relates to the field of marking of ammunition. In particular, the invention relates to a method of providing a mark to a case of a cartridge of ammunition, wherein the mark comprises at least one sub-mark and is suitable for identification or for tracking of the cartridge. Further, the invention relates to a device for providing such a mark to a cartridge of ammunition.

BACKGROUND

Ammunition marking is an important tool for tracking of ammunition as well as for controlling the use of it. Further, it can be used for quality assurance and for ensuring proper use of ammunition by clearly identifying the sort of ammunition, in particular its type and caliber. In connection with the use of ammunition by military and law enforcement forces, marking of ammunition is important for stock pile management, transportation and record keeping. Particularly in the civil sector, marking ammunition potentially helps investigating crimes in which firearms are involved.

It is common that marks in the form of a stamp are applied to the bottom of a cartridge, also called round, of ammunition. However, due to the limited space available on the bottom of a cartridge, the amount of information which can be applied to the cartridge via such a marking is also very limited. There are techniques of applying a mark also to the lateral outer surface of a cartridge case. Marking the lateral outer surface of a cartridge case is, today, achieved by use of printing techniques. The usual technique of stamping, as it is applied to the bottom of the case of the cartridge, is much less suitable for application to the case in its lateral or radial direction. Thus, press stamping is not used for marking the lateral surface of the case.

It is known from US 7,823,495 B2 to use laser engraving techniques for engraving the surface of a cartridge, in particular an extractor groove which is typically placed in the area near the bottom of the case. A particular drawback of this method is that the equipment needed for laser engraving is very complex and, thus, expensive which is a decisive disadvantage for any manufacturer who wants to use the laser engraving method for marking cartridges of ammunition .

Other known techniques, namely press stamping and silk screen or similar printing techniques, have other disadvantages. As to the press stamping, in addition to the fact that this method cannot be applied to the lateral surface of a case of a cartridge, the costs for producing press stamping dies are also significant, similar to the laser engraving equipment. As to the printing techniques, the marks provided by these techniques tend to lose their readability after the cartridge has been fired and can easily be counterfeited.

Accordingly, there is a need for a less expensive method for marking ammunition which is capable of applying marks also to the lateral surface of an ammunition cartridge case so as to increase the maximum amount of information provided by the mark .

SUMMARY

It is an object of the present invention to provide a method and a device which allow for efficiently marking ammunition by a durable and reliable mark which cannot easily be removed .

This problem is solved by the method according to claim 1 and the device according to claim 10, respectively. Further preferred features of the method or device are recited in the dependent claims and detailed in the following description.

DESCRIPTION

Throughout this text, the cartridge of ammunition is also referred to as a round of ammunition. The inventive method of providing a mark to a case of a cartridge of ammunition, or to a round of ammunition, the mark comprising at least one sub-mark and being suitable for identification or for tracking of the cartridge, makes use of at least one compression means which selectively radially indents a circumferential surface of a bottom of the case, thereby forming the at least one sub-mark. The means is preferably present in the form of a finger, but the form of the embodiment for the compression means can be chosen depending on the space available next to the cartridge or round of ammunition.

A cartridge or round of ammunition usually comprises a case, a primer, a propellant and, optionally, one or more projectiles. The propellant usually is a chemical composition to be ignited by the primer which then explodes and generates high pressure which can be used to propel a projectile. Common names for propellants are "powder", "gunpowder", "smoke-less powder" and "black powder". In order to ignite the propellant, the cartridge usually comprises the primer which, upon impact of a firing pin, ignites the propellant. The primer can be provided with a separate casing enclosing a priming mixture. Further, at least the propellant, usually also the primer and, optionally, also a projectile are at least partially enclosed in a case at least part of which forms at least part of an outer surface of the cartridge or round. If a projectile is provided, the projectile usually is at least partially enclosed in the case on the side of the propellant opposite to the primer. Projectiles are, however, not essential or required .

The case usually is cylindrical, conical or bottle-shaped and has an axis of symmetry defining longitudinal, radial and circumferential directions. In the longitudinal direction, which is parallel to the axis of symmetry, the propellant usually is located between a primer and a projectile or several projectiles. Radially, i. e. perpendicular to the axis of symmetry, the case usually forms the outer surface of the cartridge .

Most cartridges further have an extraction groove in the case. This is usually applied to the case in the vicinity of a bottom of the case. In the present application, the sub- marks can be applied both to the bottom of the case and to the extraction groove. In other words, the extraction groove is, in this context, to be considered to be part of the bottom of the case.

The mark to be applied to the case is meant to identify a cartridge. The mark can be used for example to individually identify a specific piece of ammunition or to more generally identify its type, such as its caliber. For example, the mark can be a, possibly encoded, lot number or a serial number of the cartridge. Hence, the mark in the present context is not merely an accidental or random mark on the surface of a case but an intentionally applied mark which can have the form of indentations which are sized and/or separated from each other in a recognizable manner so as to form a barcode or similar. At least one compression means is used to selectively radially indent a circumferential surface of a bottom of the case to thereby form the at least one sub-mark. Indenting the surface means that the compression means is pressed into the surface of the case in the vicinity of its bottom, thereby deforming the case, in order to form a groove into the case. Pressing the compression means into the surface leads to locally stressing the surface of the case beyond its elastic limit so that an inelastic deformation is achieved.

The bottom of the case in the sense of the present invention is defined to comprise the portion of the case which extends from an extraction groove towards the end of the case opposite to any projectile. Preferably, the bottom of the case additionally means the extraction groove.

In contrast to the prior art according to US 7,823,495 B2, it is not necessary for the present invention to use expensive laser equipment for engraving a surface of the case of the cartridge .

Accordingly, the inventive method allows the application of marks to the circumferential surface of the bottom of the case of the cartridge of ammunition in an inexpensive way. The marks thus applied are not more easily removable or less durable than marks resulting from press stamping, laser engraving or printing.

Preferably, the mark comprises a plurality of sub-marks. By using a plurality of sub-marks it is possible to encode relatively complex information on the surface of the case. An example for a mark having a plurality of sub-marks is a barcode consisting of several indentations of different widths along the circumferential direction of the case.

In a preferred embodiment, the sub-mark is at least one of a material displacement, a deformation, a scratch and a hole. The sub-mark preferably has a radial minimum depth for the sub-mark being effectively protected against wear or intentional removal of it by an unauthorized person. A preferred minimum depth of the sub-mark is about 10% of the thickness of the case. Here, the thickness of the case means the thickness of the material, typically a metal, which radially and circumferentially encloses e. g. the propellant.

Preferably, the mark provides information on the basis of at least one of an absolute position of the at least one sub- mark on the case, a relative position of the at least one sub-mark with respect to at least one further sub-mark, the existence or non-existence of the at least one sub-mark at a predetermined position, a depth of the at least one sub-mark on the case, a width of the at least one sub-mark and a modulation in depth or width of the at least one sub-mark.

All of the above-mentioned features of the sub-mark can be used for encoding or decoding of information applied to the case via the sub-marks . The absolute position of the sub- mark is meant to be the position of the sub-mark in relation to the case as opposed to a relative position in relation to other sub-marks on the case. The depth and width of the sub- mark can be detected by a respective detector, as can the modulation in depth or width of the at least one sub-mark.

In a preferred embodiment, the at least one compression means comprises a material which is harder than a material of the case. It is preferred that the compression means is harder than the material of the case to ensure that the sub-marks are reliably indented in the surface of the case. A possible material for the compression means would, therefore, be diamond, diamond-like carbon or similar materials. Alternatively, it is possible that the compression means is made of a metal or an alloy which preferably is harder than the material of the case. In a preferred embodiment, the at least one compression means is moved by an actuator from an idle position to an active position for radially indenting into the circumferential surface of the bottom of the case. Using such an actuator allows to very precisely mark the case.

Further preferably, the active position of the compression means is variable and the depth of the at least one sub-mark on the case can be modulated by varying the active position of the compression means. Varying the depth of the sub-mark increases the degrees of freedom for encrypting information via the mark on the case .

The variable active position of the compression means can be understood to mean a plurality of active positions or a continuously variable active position which can be controlled by the actuator. In any case, the amount and density of information which can be applied to the cartridge can be significantly increased.

In a preferred embodiment, a plurality of compression means selectively radially indents a circumferential surface of the bottom of the case. If the plurality of compression means is used, the method for marking the case can be made a lot more efficient because several marks can simultaneously be applied to the case.

Further preferably, a computer system controls the at least one compression means, preferably the plurality of compression means, and a position of the cartridge in order to generate a predetermined mark on the cartridge in accordance with the above mentioned methods.

A device according to the present invention for providing a mark to a case of a cartridge of ammunition, the mark comprising at least one sub-mark and being suitable for identification or for tracking of the cartridge, comprises at least one compression means. The compression means is configured for selectively radially indenting a circumferential surface of a bottom of the case for thereby forming the at least one sub-mark, the device preferably being configured for carrying out at least one of the above- outlined methods.

It is preferred that the device comprises an actuator which is configured for moving the at least one compression means between an idle position, in which the compression means does not interact with the case, and an active position, in which the compression means interacts with the case such that the at least one sub-mark is formed. The active position of the compression means is a position in which the compression means radially indents into the circumferential surface of the bottom of the case in order to form the sub-mark.

In a preferred embodiment, the active position of the compression means is variable. This can be understood as a plurality of active positions which means a plurality of positions to which the compression means can be moved by the actuator and, in these positions, interacts with the case such that a sub-mark can be formed. Alternatively, the active position of the compression means being variable can also be understood as a continuous variation of the active position to indent a plurality of different depths of the sub-mark into the case.

In a preferred embodiment, the device comprises a plurality of compression means which are configured for selectively radially indenting a circumferential surface of the bottom of the case for thereby forming a plurality of sub-marks. The use of a plurality of compression means makes the device more efficient and allows marking of a case in less time because the plurality of sub-marks can be applied to the case simultaneously . In a further preferred embodiment, the device comprises a computer system which is configured for controlling the at least one compression means, preferably a plurality of compression means, and for positioning the cartridge in order to allow for generating a predetermined mark on the cartridge .

The present method and device and their preferred embodiments as outlined above allow for solving the above-identified problem. In particular, marking a case of a cartridge of ammunition is made possible in a very efficient manner, it being possible to apply the mark to the lateral surface of the case with a high density of information. The mark cannot easily be removed from the cartridge and is resistant to wear .

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a bottom view of a case of a cartridge of ammunition which illustrates a preferred method.

FIG. 2 is a side view of the case of the cartridge of FIG. 1 illustrating a portion of the case.

DETAILED DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a preferred method for providing a mark to a case 13 of a cartridge of ammunition. The mark comprises a plurality of sub-marks 12 which are applied to the case 13 by, in the illustrated embodiment, a plurality of compression fingers 10 which selectively radially indent a circumferential surface of a bottom 20 of the case 13.

The bottom view of the case 13 of FIG. 1 shows the bottom surface of the case 13 by which the firing pin of a gun activates the primer in the case 13 to ignite the propellant and, optionally, fire the projectile. The bottom of the case 13 is located at the end of the cartridge opposite to any projectile. This bottom surface of the case 13 can, in addition to the present invention, be marked by a head stamp in the usual manner, as known from the prior art. Such head stamp is, however, not illustrated in FIG. 1.

What FIG. 1 illustrates is that a circumference of the bottom 20 forms a circle, if no indentation is applied. At certain positions along the circumference, compression fingers 10 are illustrated as indenting the circumferential surface of the bottom 20, which surface cannot be seen in FIG. 1, to thereby form sub-marks 12. In FIG. 1, eight equally circumferentially distanced compression fingers 10 are illustrated. However, the method can be carried out by use of a single compression finger 10 or almost any higher number of compression fingers 10 with regular or irregular, fixed or variable circumferential distances to each other.

As can be seen in FIG. 1, at selected positions along the circumference, sub-marks are applied or not-applied by the compression fingers 10. In the example of FIG. 1, eight predetermined positions exist for forming a sub-mark or not, namely, the angular positions of the compression fingers 10. Whether or not a sub-mark exists at these respective predetermined positions is used to encode information to the case 13 via the mark for identification and/or tracking of the cartridge. At the angular position 14 on the circumferential surface of the bottom 20, a compression finger 10 is present and could indent the surface for forming a sub-mark. However, in the situation illustrated in FIG. 1, no sub-mark 12 is formed at this position 14 so that the nonexistence of a sub-mark at this position can be detected by a respective detector.

By using predetermined positions for the sub-marks, it is possible to encode information, e.g. on the basis of the binary system, also on the basis of non-existing indentations at one or more of these positions.

However, in addition to simply detecting whether or not a sub-mark is present at a certain predetermined position on the surface of the case 13, it is also possible to vary the shape of the sub-mark 12, in particular the depth of the indentation, to thereby add further degrees of freedom in order to increase the information density of the mark.

FIG. 1 illustrates a couple of active compression fingers 11.1 as well as a couple of idle compression fingers 11.2. While the active compression fingers 11.1 are illustrated to indent and form a respective sub-mark 12, the idle compression fingers 11.2 are not in contact with the case 13.

A preferred device for carrying out the method illustrated in FIG. 1 comprises a plurality of compression fingers 10 which, by use of actuators, can be moved between an idle position and at least one active position. In order to increase the number of degrees of freedom and, thereby, the information density of the mark, it is further preferred that the actuators are configured for moving the compression fingers 10 between an idle position and a variable active position. The variable active position can be a plurality of stepwise differing active positions or a continuously varying active position.

Preferably, the actuators of the compression fingers 10, in particular if there is more than one compression finger 10 involved, are controlled by a computer system which is configured to coordinate the compression fingers and the position and orientation of the cartridge and its case 13. Thereby, a preferred method can be realized in a very efficient way, wherein a plurality of sub-marks 12 can be applied to the case 13 simultaneously. FIG. 2 is a side view of the case 13 and illustrates the bottom 20 of the case 13 as a portion of the case 13 and an extractor groove 21.

This portion of the case 13 usually contains parts of the primer. However, in the context of the present document, this portion of the cartridge, i.e. the bottom 20 and preferably also the extractor groove 21, is considered to be the bottom 20 of the case 13.