Patent Application
20240377172
The present invention relates to a method and a tool arrangement for producing a base piece of a multi-part cartridge case. Furthermore, the present invention relates to a base piece for a multi-part cartridge case and to a multi-part cartridge case.
Multi-part cartridge cases are basically known and are subdivided at least into a base piece facing the primer for receiving a primer and a case jacket firmly connected to the base piece for receiving a projectile. The base piece usually has an extraction groove to support the ejection of a fired, empty cartridge case. Via the extractor groove, a so-called extractor of a firearm can transport the empty cartridge case to a so-called ejector of the firearm, which finally ejects the empty cartridge case. The extraction groove is formed on a circumferential wall of the annular base piece as a circumferential groove or recess, which has a rear step edge oriented essentially transversely to the longitudinal axis direction, a radially inner side base surface oriented essentially in the longitudinal axis direction and a transition edge adjacent to the base surface and inclined in relation to the longitudinal axis direction. In the state of the art, the extraction groove has so far been produced by machining, which has not proven to be optimal in terms of manufacturing costs and favorable mass production. In the domain of the production of one-piece cartridge cases, there are already approaches in the state of the art to manufacture the extractor groove by deforming. So-called segmented punch and die tool arrangements are used here, by means of which the internal geometry for holding the projectile and the primer is first produced and finished and then the extraction groove is introduced on the outside in a subsequent process step. These punch and die tool arrangements cannot be easily transferred to multi-part cartridge cases.
For example, FR 1113479 discloses a 3-part cartridge case consisting of a base piece with an extraction groove, a case jacket and a fastening part. Another multi-part cartridge case is known from US 2019/0226817, in which the base piece also comprises an extraction groove.
The inventors of the present invention have identified considerable potential for improvement with regard to the extraction groove, namely on the one hand with regard to manufacturing tolerances and on the other hand with regard to achievable holding forces for fastening the base piece and case jacket together. It was found that it is not always possible to reliably ensure that the holding force of the base piece and case jacket of multi-part cartridge cases can withstand the considerable forces when firing a firearm. The desired manufacturing tolerances cannot be reliably ensured either with machining production or with previous solutions for cold-forming production of the extraction groove. In particular, when using segmented tools to produce the extraction groove, it has been found to be particularly disadvantageous that the segmented tools can produce surface defects in the portion of the extraction groove, which have a detrimental effect on the extraction function.
One task of the present invention is to overcome the disadvantages of the prior art, in particular to create a base piece for a multi-part cartridge case that is easy and inexpensive to manufacture, by means of which higher holding forces can be achieved between the base piece and the case jacket and/or the extractor groove of which can be manufactured with lower manufacturing tolerances.
The task is solved by the objects of the independent claims.
Accordingly, a method for manufacturing a base piece for receiving a primer for a multi-part cartridge case is provided. It may be provided that the method is used to manufacture a base piece formed in accordance with one of the aspects or exemplary embodiments of the present invention described below. Ammunition, also referred to as a cartridge, generally comprises the following components: a cartridge case; a primer for igniting the propellant powder; a propellant charge as an energy carrier; and a projectile to be fired from a firearm. Multi-part cartridge cases generally comprise at least one base piece facing the primer for receiving the primer and a case jacket firmly connected to the base piece for receiving the projectile. When the case jacket and base piece are attached to one another, an outer side of the case jacket can rest against an inner side of the base piece; in other words, the base piece can at least partially receive the case jacket.
According to the invention, in the method for manufacturing a base piece, an extraction groove for engagement by a firearm ejector is produced by forming or shaping, in particular by cold forming, before a receptacle for the case jacket of the multi-part cartridge case for receiving a projectile is produced. The receptacle for the case jacket can also be manufactured by forming or shaping, in particular by cold forming, and can, for example, be formed as a central recess in the base piece. Deforming is generally a non-cutting manufacturing process in which the base piece is brought into a different shape without removing or adding material from the base piece. The mass of the base piece remains the same during deforming. A cold forming process, such as impact extrusion, can be used to deform the extraction groove and/or the receptacle of the case jacket. During deforming, the material of the base piece characteristically hardens, so that the base piece has a higher strength and/or a higher hardness after deforming, at least in the deformed portions, i.e. in the portion of the extraction groove and possibly in the portion of the receptacle for the case jacket. Due to the higher strength and/or the higher hardness, higher holding forces can be achieved between the base piece and the case jacket and/or between the base piece and the primer. As a result, a cartridge case with a base piece manufactured using the method according to the invention can withstand greater internal pressures when the projectile is fired. In addition, because the extraction groove is deformed before the receptacle for the case jacket is manufactured, simpler and less expensive tools can be used to manufacture the extraction groove. A further advantage of the method according to the invention is that the dimensional accuracy of the extraction groove during deforming is higher and can be ensured more reliably because the tools used for deforming the extraction groove do not produce any surface defects in the portion of the extraction groove, as can occur, for example, with segmented tools used in the prior art. These surface defects can have a negative influence on the extraction function, so that a base piece produced using the method according to the invention has a more reliable extraction function. By manufacturing the receptacle after deforming the extraction groove, it can also be ensured that the high dimensional accuracy and the higher hardness or higher strength are not impaired by the manufacturing of the receptacle.
In an exemplary embodiment of the method according to the invention, the extraction groove is already completed before production of the receptacle begins. In this way, it can be ensured that the dimensional accuracy of the extraction groove and the strength and/or hardness of the base piece are ensured independently of the production of the receptacle for the case jacket and/or are not impaired by a simultaneous or prior production of the receptacle.
In a further exemplary embodiment of the present invention, the extraction groove is not interfered with during manufacture of the receptacle. In this way, it can be ensured that the dimensional accuracy of the extraction groove and the strength and/or hardness of the base piece are not impaired after the extraction groove has been deformed, for example by segmented tools which can be used to manufacture the receptacle and which can produce surface defects or elevations in the extraction groove which can impair the extraction function.
According to a further aspect of the present invention, which may be combined with the preceding aspects and exemplary embodiments, there is provided a method of manufacturing a base piece for receiving a primer for a multi-part cartridge case. It may be provided that the method is used to manufacture a base piece formed according to one of the aspects or exemplary embodiments of the present invention described below. Ammunition, also referred to as a cartridge, generally comprises the following components: a cartridge case; a primer for igniting the propellant powder; a propellant charge as an energy carrier; and a projectile to be fired from a firearm. Multi-part cartridge cases generally comprise at least one base piece facing the primer for receiving the primer and a case jacket firmly connected to the base piece for receiving the projectile. When the case jacket and base piece are attached to one another, an outer side of the case jacket can rest against an inner side of the base piece; in other words, the base piece can at least partially receive the case jacket. For example, the base piece can have a central recess to receive the case jacket.
In the method according to the invention, an extraction groove for engagement by a firearm ejector is produced by deforming, in particular cold forming, in such a way that a primer-side groove flank of the extraction groove is formed by a material displacement directed in the longitudinal direction of the base piece without material being displaced radially outwards. Deforming is generally a non-cutting manufacturing process in which the base piece is brought into a different shape without removing or adding material from the base piece. The mass of the base piece remains the same during deforming. The primer-side groove flank of the extraction groove can be oriented transversely, in particular perpendicularly, to the longitudinal direction of the base piece. The firearm ejector can grip and eject the empty cartridge case after firing the projectile via the extraction groove or the primer-side groove flank. The primer-side groove flank can be the most important point for a reliable extraction function. By deforming the groove flank in accordance with the invention, the groove flank is produced directly by axial material deformation without the outer diameter of the base piece increasing during deformation of the extraction groove due to a radial outward displacement of the material. In the portions where material is displaced, the diameter of the base piece can be smaller after deforming the extraction groove than before deforming the extraction groove. As a result of such deforming, the material characteristically has a higher strength and/or a higher hardness on the one hand and, on the other hand, the deviations in strength and/or hardness are smaller; in other words, the strength curve and/or the hardness curve in the base piece is more homogeneous, particularly in the portion of the extraction groove and/or in the receptacle for the case jacket and/or the primer. It can thus be ensured more reliably that there is sufficient material strength and/or material hardness to ensure the necessary holding forces between the base piece and the case jacket and/or between the base piece and the primer. A further advantage of the method according to the invention is that the groove flank can be produced with greater dimensional accuracy and, in particular, the transition from the groove flank on the one hand to a jacket of the base piece and on the other hand to a groove base adjacent to the groove flank and oriented essentially in the longitudinal direction of the base piece can always be produced in the same way, for example as a sharp-edged shoulder, due to the material displacement directed in the longitudinal direction, and the empty cartridge case can thus be reliably ejected. In other words, the extraction groove or the primer-side groove flank has a higher dimensional accuracy, wherein the higher dimensional accuracy can also be ensured more reliably. A further advantage of the method according to the invention is that more cost-effective tools with a simpler structure can be used to produce the extraction groove, which additionally cannot produce surface defects in the portion of the extraction groove, in particular in the portion of the groove flank, which can impair the extraction function, as is the case with the segmented tools used in the state of the art.
In an exemplary embodiment of the present invention, the production of the extraction groove is accompanied by a flow of material in the opposite direction to the forming direction. In other words, there is a flow of material against the direction of movement of a tool used for deforming the extraction groove. In this way, it can be ensured that the material is not displaced outwards in a radial direction during deforming.
According to a further exemplary embodiment of a method according to the invention, the extraction groove is first preformed in such a way that a primer-side groove flank of the extraction groove is inclined at an angle of less than 90° with respect to the longitudinal direction of the base piece. It may be provided that the extraction groove is preformed by means of a pair of preforming punches and dies. In this way, the material does not have to be deformed as much initially, so that simpler and less expensive tools can be used.
In a further exemplary embodiment of a method according to the invention, the pre-formed extraction groove is further deformed by means of backwards extrusion. It may be provided that the extraction groove is further deformed by means of a second pair of punches and dies. Backwards extrusion is an extrusion process in which the material flow and the direction of punch movement are opposite. This means that the material flow is directed against the forming direction and against the movement of the forming tool. In this embodiment, the groove flank is only oriented at an angle of 90° transversely to the longitudinal direction of the base piece after further deforming. The two-stage production of the extraction groove means that simpler and more cost-effective tools can be used for the individual steps. It may also be provided that the die of the pair of preforming punches and dies is also used for the second step of further deforming the already preformed extraction groove in order to be able to deform the extraction groove more quickly and cost-effectively.
According to a further aspect of the present invention, which may be combined with the preceding aspects and exemplary embodiments, there is provided a method of manufacturing a base piece for receiving a primer for a multi-part cartridge case. It may be provided that the method is used to manufacture a base piece formed according to one of the aspects or exemplary embodiments of the present invention described below. Ammunition, also referred to as a cartridge, generally comprises the following components: a cartridge case; a primer for igniting the propellant powder; a propellant charge as an energy carrier; and a projectile to be fired from a firearm. Multi-part cartridge cases generally comprise at least one base piece facing the primer for receiving the primer and a case jacket firmly connected to the base piece for receiving the projectile. When the case jacket and base piece are attached to one another, an outer side of the case jacket can rest against an inner side of the base piece; in other words, the base piece can at least partially receive the case jacket. For example, the base piece can have a central recess to receive the case jacket.
According to the invention, in the method an extraction groove for engagement by a firearm ejector is manufactured by deforming, in particular cold forming, and without any post-machining. Deforming is generally a non-cutting manufacturing process in which the base piece is brought into a different shape without removing or adding material to the base piece. The mass of the base piece remains the same during deforming. Since no machining post-processing is required after deforming the extraction groove, the process according to the invention is simpler, faster and more cost-effective. In addition, a higher and more reliable dimensional accuracy of the extraction groove can be ensured.
In an exemplary embodiment, at least one manufacturing step for producing an inner and/or outer geometry of the base piece can be carried out by punching. This can significantly increase manufacturing efficiency. In particular, the manufacturing performance can be greatly improved so that the manufacturing costs can be significantly reduced, in particular by around 30%. This makes the manufacture of the cartridge cases much more suitable for mass and/or automated production. In an exemplary embodiment of the cartridge case, the base piece comprises an annular jacket and a through hole extending through the jacket, in particular a receiving recess for the primer. The through hole can be produced at least sectionally by means of punching. In other words, an internal geometry of the base piece can be produced at least sectionally by means of punching.
According to a further aspect of the present invention, which can be combined with the preceding aspects and exemplary embodiments, there is provided a tool arrangement for introducing an extraction groove for engagement by a firearm ejector in a case blank for producing a base piece for receiving a primer for a multi-part cartridge case. The extraction groove allows the firearm ejector to grip and eject the empty cartridge case after the projectile has been fired. It may be provided that the tool arrangement is used to produce a base piece formed in accordance with one of the aspects or exemplary embodiments of the present invention described below. Ammunition, also referred to as a cartridge, generally comprises the following components: a cartridge case; a primer for igniting the propellant powder; a propellant charge as an energy carrier; and a projectile to be fired from a firearm. Multi-part cartridge cases generally comprise at least one base piece facing the primer for receiving the primer and a case jacket firmly connected to the base piece for receiving the projectile. When the case jacket and base piece are attached to one another, an outer side of the case jacket can rest against an inner side of the base piece; in other words, the base piece can at least partially receive the case jacket. For example, the base piece can have a central recess to receive the case jacket.
The tool arrangement can be adapted to perform a pressure forming process. According to the invention, the tool arrangement comprises a particularly segmented die for fixing a face side of the case blank and for engaging in a case cavity of the case blank and a case-shaped press plunger for circumferentially engaging around the case blank. The die and/or the press plunger can be formed to be rotationally symmetrical. The case blank can, for example, be produced in a first step by setting a piece of wire or by punching it out of a plate. In a further step, the case cavity into which the die of the tool arrangement according to the invention engages during deforming can be produced, for example by extrusion. It may be provided that the case cavity forms the primer receptacle on the finished base piece.
According to an aspect of the present invention, the press plunger is movable relative to the die for deforming, in particular cold forming, the extraction groove. In particular, the press plunger can be movable strictly axially, in particular in the longitudinal direction of the base piece or the case blank, relative to the die. In other words, a purely translational movement of the press plunger can be provided to produce the extraction groove. The need for additional radial movability in segmented tools used in the prior art, in which individual segments of the segmented tool move radially towards each other for pressing or deforming, can be dispensed with. Compared to tools commonly used in the prior art, the tool arrangement according to the invention has a simpler structure and is therefore less expensive and less prone to errors. The tool arrangement according to the invention, and in particular the press plunger according to the invention, can also be used to produce the extraction groove without creating elevations or surface defects in the portion of the extraction groove between the individual segments of the tool, which can have a detrimental effect on the function of the firearm ejector and/or have to be subsequently removed by machining with additional effort and additional costs. By deforming the extraction groove with the tool arrangement according to the invention, a higher strength and/or a higher hardness of the base piece can also be achieved so that higher holding forces are created between the base piece and the case jacket and/or between the base piece and the primer. A further advantage of a tool tensioning arrangement according to the invention is that a more homogeneous hardness and/or strength curve can be achieved in the base piece.
It should be understood that the embodiments made with respect to a method for producing a base piece according to the invention apply analogously to the tool arrangement according to the invention.
In an exemplary embodiment of the present invention, the press plunger is circumferentially closed. Alternatively or additionally, the press plunger is made from a single piece. Such a press plunger does not cause any unevenness or surface defects when producing the extraction groove, such as occur in the prior art when using segmented tools for deforming the extraction groove.
According to a further aspect of the present invention, which can be combined with the preceding aspects and exemplary embodiments, there is provided a tool arrangement for introducing an extraction groove for engagement by a firearm ejector in a case blank for producing a base piece for receiving a primer for a multi-part cartridge case. The extraction groove allows the firearm ejector to grip and eject the empty cartridge case after the projectile has been fired. It may be provided that the tool arrangement is used to produce a base piece formed in accordance with one of the aspects or exemplary embodiments of the present invention described below. Ammunition, also referred to as a cartridge, generally comprises the following components: a cartridge case; a primer for igniting the propellant powder; a propellant charge as an energy carrier; and a projectile to be fired from a firearm. Multi-part cartridge cases generally comprise at least one base piece facing the primer for receiving the primer and a case jacket firmly connected to the base piece for receiving the projectile. When the case jacket and base piece are attached to one another, an outer side of the case jacket can rest against an inner side of the base piece; in other words, the base piece can at least partially receive the case jacket. For example, the base piece can have a central recess to receive the case jacket.
The tool arrangement can be adapted to perform a pressure forming process. According to the invention, the tool arrangement comprises a die for fixing a face side of the case blank and for engaging in a case cavity of the case blank and a press plunger for gripping around the outside of the case blank. The die and/or the press plunger can be formed to be rotationally symmetrical. The press plunger can be formed in a case-shaped manner. The case blank can, for example, be produced in a first step by setting a piece of wire or by punching it out of a plate. In a further step, the case cavity into which the die of the tool arrangement according to the invention engages during deforming can be produced, for example by extrusion. It may be provided that the case cavity forms the primer receptacle on the finished base piece.
According to an aspect of the present invention, the press plunger has a material displacement projection on its inner side facing the case blank, by means of which, during a pressing movement of the press plunger relative to the die, the tool arrangement forms a primer-side groove flank of the extraction groove for engagement by a firearm ejector. In particular, the pressing movement can be purely axial, especially in the longitudinal direction of the base piece or the case blank. It may be provided that the material displacement projection is formed radially circumferentially and/or planar, in particular without elevations or recesses. The material displacement projection can be oriented at an angle of 90° or at an angle of less than 90° in relation to the longitudinal direction of the base piece or the case blank. The material displacement projection can achieve a higher dimensional accuracy of the extraction groove and it can be ensured that no elevations or surface defects occur in the portion of the extraction groove that could impair the extraction function. It can also be ensured that the material is not displaced radially outwards during deforming. A further advantage of the tool arrangement according to the invention is that the extraction groove and in particular the groove flank can be produced with greater dimensional accuracy and in particular the transition from the groove flank on the one hand to a jacket of the base piece and on the other hand to a groove base adjacent to the groove flank and oriented essentially in the longitudinal direction of the base piece can always be produced in the same way, for example always as a sharp-edged shoulder, due to the material displacement directed in the longitudinal direction and the empty cartridge case can therefore be ejected more reliably. In other words, the extraction groove or the primer-side groove flank has a higher dimensional accuracy, wherein the higher dimensional accuracy can also be ensured more reliably.
It should be understood that the embodiments made with respect to a method for producing a base piece according to the invention apply analogously to the tool arrangement according to the invention.
In an exemplary embodiment of a tool arrangement according to the invention, the material displacement projection has a pressing surface inclined with respect to the direction of pressing movement. The direction of pressing movement can coincide with the longitudinal direction of the base piece or the case blank. In an exemplary further development, an angle of inclination of the material displacement projection is in the range from 10° to 80°, in particular in the range from 15° to 75°, in particular in the range from 20° to 70° or in the range from 25° to 65°. It may be provided that the extraction groove is preformed with the inclined pressing surface and the preformed extraction groove is then further deformed.
According to a further aspect of the present invention, which can be combined with the preceding aspects and exemplary embodiments, there is provided a tool arrangement for introducing an extraction groove for engagement by a firearm ejector into a case blank or into a base piece pre-stage for producing a base piece for receiving a primer for a multi-part cartridge case. The extraction groove allows the firearm ejector to grip and eject the empty cartridge case after the projectile has been fired. It may be provided that the tool arrangement is used to produce a base piece formed in accordance with one of the aspects or exemplary embodiments of the present invention described below. Ammunition, also referred to as a cartridge, generally comprises the following components: a cartridge case; a primer for igniting the propellant powder; a propellant charge as an energy carrier; and a projectile to be fired from a firearm. Multi-part cartridge cases generally comprise at least one base piece facing the primer for receiving the primer and a case jacket firmly connected to the base piece for receiving the projectile. When the case jacket and base piece are attached to one another, an outer side of the case jacket can rest against an inner side of the base piece; in other words, the base piece can at least partially receive the case jacket. For example, the base piece can have a central recess to receive the case jacket.
The tool arrangement can be adapted to perform a pressure forming process. The tool arrangement further comprises a forming punch comprising at least two, in particular exactly two, punch parts for deforming the finished extraction groove, which are arranged for circumferentially gripping the case blank or the base piece pre-stage. The forming punch can be adapted to displace material from the case blank or the base piece pre-stage by means of a pressing movement in order to imprint or form the structure of the extraction groove. The punch parts, in particular the punch halves, can be movably mounted towards each other and/or formed identically. The punch parts can grip and/or clamp, in particular cold-form, the case blank or the base piece pre-stage in a pincer-like manner.
Furthermore, the tool arrangement according to the further aspect of the invention comprises an anvil which can be moved translationally relative to the forming punch for fixing a face side opposite the face side of the case blank or the base piece pre-stage, which can be brought into abutment contact with the forming punch. For example, the anvil can have at least one operating state, in which it is brought into abutment contact with the forming punch, and another operating state, in particular a passive state, in which it is brought out of abutment contact with the forming punch. In particular, the anvil can translate between the punch parts, in particular the punch halves.
According to a further aspect of the invention, facing abutment contact surfaces of the forming punch and the anvil are shape-matched to one another. For example, the abutment contact surfaces can be shape-matched to one another in such a way that self-centering occurs during translational movement of the anvil relative to the forming punch, in particular in the direction of engaging the abutment contact.
In an exemplary embodiment of the tool arrangement according to the invention, the abutment contact surface of the forming punch is at least sectionally, in particular completely, concave in shape and/or the abutment contact surface of the anvil is at least sectionally, in particular completely, convex in shape. When the stop contact is made, there can be essentially full-surface abutment contact, wherein it is ensured in particular that a relative movement of the abutment and forming punch transversely to the translational direction of movement of the anvil is prevented. According to an exemplary further development, the abutment contact surface of the forming punch forms a concave receptacle for the anvil and the anvil essentially fills this receptacle completely. For example, the receptacle can have a semi-spherical shape and the anvil can have a shape-matched shape.
In an exemplary embodiment of the tool arrangement according to the invention, the anvil comprises a central projection adjoining the abutment contact surface, which is arranged to engage in the receptacle for the case jacket of the multi-part cartridge case in order to retain the structure of the receptacle or the structure from which the receptacle is to be subsequently produced during the shaping of the extraction groove.
In a further exemplary embodiment of the present invention, the tool arrangement is adapted to generate a recognizable separation point with a dimension of up to 0.2 m, in particular 0.15 mm or about 0.1 mm, on the outside of the base piece. For this purpose, the punch parts can displace material of the base piece during pressing of the base piece and clamp it between them, resulting in a separation point or seam protruding from the outside of the base piece.
According to a further aspect of the present invention, which can be combined with the preceding aspects and exemplary embodiments, there is provided a base piece for receiving a primer for a multi-part cartridge case, which is produced by a method according to the invention and/or by a tool arrangement according to the invention.
According to a further aspect of the present invention, which can be combined with the preceding aspects and exemplary embodiments, a base piece for receiving a primer for a multi-part cartridge case is provided. The base piece may be produced by a method according to the invention and/or by a tool arrangement according to the invention. It should be understood that the foregoing embodiments and advantages of methods and tool arrangements according to the invention apply analogously to a base piece according to the invention. Ammunition, also referred to as a cartridge, generally comprises the following components: a cartridge case; a primer for igniting the propellant powder; a propellant charge as an energy carrier; and a projectile to be fired from a firearm. Multi-part cartridge cases generally comprise at least one base piece facing the primer for receiving the primer and a case jacket firmly connected to the base piece for receiving the projectile. When the case jacket and base piece are attached to one another, an outer side of the case jacket can rest against an inner side of the base piece; in other words, the base piece can at least partially receive the case jacket. For example, the base piece can have a central recess to receive the case jacket.
The base piece comprises an annular jacket with a central priming bore and a receptacle opening into the priming bore for a case jacket of the multi-part cartridge case for receiving a projectile. The receptacle for the case jacket can open directly into the priming bore or be separated from the priming bore by a web. In this case, a through bore can be provided in the web in order to fluidly connect the priming bore with the receptacle. The base piece can be formed rotationally symmetrically and define an axis of rotation which is oriented in the longitudinal direction of the base piece.
According to an aspect of the present invention, the jacket has an extraction groove for engagement by a firearm ejector. Via the extraction groove, the firearm ejector can grip and eject the empty cartridge case after the projectile has been fired. The extraction groove has a primer-side groove flank oriented transversely, in particular perpendicularly, to the longitudinal direction of the base piece and a groove base opening into the primer-side groove flank and oriented essentially in the longitudinal direction of the base piece. According to the invention, the hardness of the jacket on the primer-side groove flank deviates from the hardness of the jacket on the groove base by less than 40%. Such a hardness profile can be produced, for example, by deforming the extraction groove and possibly the receptacle for the case jacket and the resulting degree of deformation of the material. The degree of deformation is the measure of the change in shape when producing the base piece according to the invention. The hardness of the material can, for example, depend directly on the degree of deformation. A hardness profile according to the invention is therefore characteristic of a deforming production of the extraction groove of the base piece. The Vickers hardness, for example, can be used as a measure of the hardness of the material.
In an exemplary embodiment of the present invention, the hardness of the jacket on the primer-side groove flank deviates from the hardness of the jacket on the groove base by less than 35%. In particular, the hardness of the jacket on the primer-side groove flank deviates from the hardness of the jacket on the groove base by less than 30%, less than 25%, less than 20%, less than 15% or less than 10%. In an exemplary further development, the hardness of the jacket on the primer-side groove flank essentially corresponds to the hardness of the jacket on the groove base. In the further development, there is thus a homogeneous hardness profile of the base piece in the portion of the extraction groove.
According to a further aspect of the present invention, which can be combined with the preceding aspects and exemplary embodiments, a base piece for receiving a primer for a multi-part cartridge case is provided. The base piece may be produced by a method according to the invention and/or by a tool arrangement according to the invention. It should be understood that the foregoing embodiments and advantages of methods and tool arrangements according to the invention apply analogously to a base piece according to the invention. Ammunition, also referred to as a cartridge, generally comprises the following components: a cartridge case; a primer for igniting the propellant powder; a propellant charge as an energy carrier; and a projectile to be fired from a firearm. Multi-part cartridge cases generally comprise at least one base piece facing the primer for receiving the primer and a case jacket firmly connected to the base piece for receiving the projectile. When the case jacket and base piece are attached to one another, an outer side of the case jacket can rest against an inner side of the base piece; in other words, the base piece can at least partially receive the case jacket. For example, the base piece can have a central recess to receive the case jacket.
The base piece comprises an annular jacket which has a priming bore wall delimiting a priming bore extending through the jacket and a receptacle wall opening into the priming bore wall and forming a receptacle for a case jacket of the multi-part cartridge case for receiving a projectile. The base piece can be formed to be rotationally symmetrical and define an axis of rotation which is oriented in the longitudinal direction of the base piece. According to the invention, the hardness of a core section of 25% to 75% of the wall thickness of the receptacle wall and/or the priming bore wall does not decrease in the longitudinal direction of the base piece from a primer-side lower side of the base piece to a projectile-side upper side of the base piece. In an exemplary further development, the hardness of the core section remains at least constant or increases continuously. In other words, the base piece has a homogeneous hardness profile in the core section of the priming bore wall and/or the receptacle wall between the lower side on the primer side and the projectile-side upper side. The Vickers hardness, for example, can be used as a measure of the hardness of the material. Such a hardness profile is characteristic for producing the extraction groove by deforming. The hardness of the material can, for example, depend directly on the degree of deformation of the material. The degree of deformation is the measure of the change in shape when producing the base piece according to the invention.
According to a further aspect of the present invention, which can be combined with the preceding aspects and exemplary embodiments, a base piece for receiving a primer for a multi-part cartridge case is provided. The base piece may be produced by a method according to the invention and/or by a tool arrangement according to the invention. It should be understood that the foregoing embodiments and advantages of methods and tool arrangements according to the invention apply analogously to a base piece according to the invention. Ammunition, also referred to as a cartridge, generally comprises the following components: a cartridge case; a primer for igniting the propellant powder; a propellant charge as an energy carrier; and a projectile to be fired from a firearm. Multi-part cartridge cases generally comprise at least one base piece facing the primer for receiving the primer and a case jacket firmly connected to the base piece for receiving the projectile. When the case jacket and base piece are attached to one another, an outer side of the case jacket can rest against an inner side of the base piece; in other words, the base piece can at least partially receive the case jacket. For example, the base piece can have a central recess to receive the case jacket.
The base piece comprises an annular jacket with a central priming bore and a receptacle, opening into the priming bore, for a case jacket of the multi-part cartridge case for receiving a projectile. According to the invention, an extraction groove for engagement by a firearm ejector is introduced into the jacket by deforming, in particular cold forming, and without machining. The extraction groove allows the firearm ejector to grip and eject the empty cartridge case after the projectile has been fired. In the state of the art, the extraction groove has to be machined after deforming, for example by machining off irregularities, which causes additional costs and additional effort. The deforming production of the extraction groove can be recognized on the finished base piece by the fact that there are no surface defects or elevations in the portion of the extraction groove and in particular in the region of a primer-side groove flank and the groove flank is thus formed particularly planar.
In an exemplary embodiment of a base piece according to the invention, the extraction groove is free of material flags in the circumferential direction. Material flags are to be understood as unevenness or elevations in the portion of the extraction groove, which in the prior art occur when the extraction groove is produced with segmented tools due to the fact that when the individual segments of the tools move towards each other, displaced material from the base piece accumulates between them and ultimately remains on the base piece as a material flag in the region of the seam between two cooperating segments. A deviation of the diameter in the portion of the extraction groove at the same axial height can be less than 0.1 mm.
According to a further aspect of the present invention, which can be combined with the preceding aspects and exemplary embodiments, a cartridge case for ammunition is provided. For example, the ammunition has a caliber in the range from 4.6 to 12.7. Ammunition, also referred to as a cartridge, generally consists of the following components: a cartridge case; a primer for igniting the propellant powder; a propellant charge as an energy carrier; and a projectile to be fired from a firearm. Multi-part cartridge cases generally comprise at least one base piece facing the primer for receiving the primer and a case jacket firmly connected to the base piece for receiving the projectile. When the case jacket and base piece are attached to each other, an outer side of the case jacket can rest against an inner side of the base piece; in other words, the base piece can at least partially receive the case jacket. For example, the base piece may have a central recess.
According to the invention, the cartridge case comprises a rotationally symmetrical case jacket and a base piece according to the invention attached thereto. It may be provided that a primer is inserted, in particular pressed into, the base piece.
Preferred embodiments are indicated in the sub-claims.
In the following, further properties, features and advantages of the invention will become clear by means of a description of preferred embodiments of the invention with reference to the accompanying exemplary drawings, in which:
In the following description of exemplary embodiments of the present invention, a base piece according to the invention for a multi-part cartridge case is generally provided with the reference numeral 1, a cartridge case according to the invention is generally provided with the reference numeral 10 and a tool arrangement according to the invention for producing a base piece is provided with the reference numeral 100.
The base piece 1 has a central recess 5 for receiving the case jacket 3. Opposite the recess 5, the base piece 1 has a further central cylindrical recess 7 in which a primer (not shown) is received. In the following description, recess 5 is referred to as receptacle 5 and recess 7 is referred to as primer receptacle 7.
The base piece 1 also has a central priming bore 15, which is delimited by an annular jacket 11 of the base piece and opens into the receptacle 5 for the case jacket 3. In the embodiment shown in
The web 17 can prevent unintentional separation of the receptacle wall 25 from the priming bore wall 23 when the projectile is fired. In a further embodiment of a base piece 1 according to the invention (see
The base piece 1 also comprises an extraction groove, which in the following is generally provided with the reference numeral 9. The extraction groove 9 is introduced into an outer side 13 of the annular jacket 11 of the base piece 1 and runs completely around the base piece 1 in the circumferential direction. A firearm ejector can grip and eject the empty cartridge case 10 via the extraction groove 9 after the projectile has been fired. The extraction groove 9 comprises a primer-side groove flank 29, which is oriented essentially perpendicular to the longitudinal direction L of the base piece 1, a radially inner-side groove base 31 oriented essentially in the longitudinal direction L and a transition edge 33 adjoining the groove base 31 and inclined with respect to the longitudinal direction L. To eject an empty cartridge case 10, the firearm ejector engages in the primer-side groove flank 29, which is thus the most important point for reliable ejection. The extraction groove 9 or the groove flank 29 is free of material flags in the circumferential direction. Material flags are unevennesses or elevations in the portion of the extraction groove 9 or the groove flank 29, which in the prior art occur between the individual segments of the tool when producing the extraction groove with segmented tools. A deviation of the diameter in the portion of the extraction groove 9 at the same axial height is less than 0.1 mm in a base piece 1 according to the invention, the dimensional accuracy of the extraction groove 9 is thus particularly high in a base piece 1 according to the invention. The groove flank 29, the groove base 31 and the transition edge 33 are thus formed particularly planar in a base piece 1 according to the invention, in particular without elevations or surface defects, so that no post-machining is necessary. Such an extraction groove 9 can be produced by a method according to the invention for introducing an extraction groove 9 into a base piece 1, which is explained in detail below.
First, a metal wire can be provided and cut or trimmed to a certain length to form a cylindrical wire section 35 (
The case cavity 41 is then recessed further and then forms the primer receptacle 7 (
In the following two manufacturing steps, the desired inner and outer geometry of the base piece 1 is produced. First, the outer geometry is pre-pressed (
The schematic production sequence illustrates that in the production method according to the invention, the extraction groove 9 is introduced into the case blank 43 and completed (
In the exemplary production process in
When simultaneously observing the producing step in
The tool arrangements according to the invention for deforming the extraction groove 9 shown in
In
First, a blank 37 is punched out of a plate (
As in the manufacturing process in
The inner and outer geometry of the base piece 1 are then pressed, in particular the transition edge 33 and the groove base 33 of the extraction groove 9 (
In the alternative producing sequence, the extraction groove 9 is also introduced into the case blank 43 and completed (
It is clear from the comparison that the base piece 1 according to the invention has a higher degree of deformation. Particularly in the portion of the receptacle 5 for the case jacket 3 and in the portion of the extraction groove 9, it can be seen that the receptacle wall 25 and the priming bore wall 23 of the base piece 1 according to the invention have a higher degree of deformation. The degree of deformation is a measure of the deformation of the base piece 1. It indicates the extent to which the material is deformed when producing a base piece 1 from a wire section 35 or a disk 37. A higher degree of deformation guides to a higher strength and/or a higher hardness of the material. The hardness of the base piece 1 depends directly on the degree of forming. Due to the higher degree of forming and the resulting higher hardness of the base piece 1, higher holding forces can be achieved between the base piece 1 and the case jacket 3 as well as between the base piece 1 and the primer. As a result, a cartridge case 10 with a base piece 1 according to the invention can withstand greater internal pressures when the projectile is fired.
A base piece 1 according to the invention, which was manufactured using a method or tool arrangement 100 according to the invention, also has a characteristic hardness profile in the jacket 11 of the base piece 1, which thus indicates that the extraction groove 9 was manufactured using the method or tool arrangement 100 according to the invention.
In
Furthermore, it can be seen from the lines 101 and 103, which run along the center of the wall thickness of the priming bore wall 23, 123 and the receptacle wall 25, 125, that the degree of deformation in the base piece 1 according to the invention increases continuously from the primer-side lower side 19 to the projectile-side upper side 21, which is not the case in the prior art base piece 2.
A varied shorter seam 133 is shown in
The features disclosed in the above description. figures and claims can be of importance both individually and in any combination for the realization of the invention in the various embodiments.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10 2021 124 431.5 | Sep 2021 | DE | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/EP2022/075605 | 9/15/2022 | WO |
