Projectile with circumferential and/or longitudinal groove

The present invention relates to a projectile, particularly a full metal jacket or partial metal jacket projectile, preferably with a caliber of less than 20 mm, especially less than 13 mm. Furthermore, the present invention also provides a tool, a device, and a method for introducing a circumferential and/or longitudinal groove into a projectile blank to manufacture a projectile according to the invention.

Projectiles can be equipped with various functional grooves, e.g., fixation or holding grooves, relief grooves to reduce abrasion in the firearm barrel, deformation grooves as predetermined breaking points both in the circumferential and longitudinal direction of the projectile, or knurling grooves for haptic purposes.

Circumferential functional grooves, such as the engagement groove for the case mouth, are usually produced on complex tool stations with various tool arrangements, for example, by cross-rolling or cross-wedge rolling. For instance, military full metal jacket projectiles are grooved to press the case mouth into the groove (crimping). This better holds the projectile in the case, which is advantageous in automatic weapons as it reduces the pressing of the projectile into the case.

However, the known methods have shown disadvantages such as the complex tool setup and the high number of tool parts. In particular, with the known methods for introducing functional grooves into the projectile body, it is not possible to increase the cycle rate easily, which negatively affects profitability, especially in mass production. Moreover, it has been found that cross-rolling the projectile to introduce circumferential grooves results in a marked transition from the outer circumference of the projectile to the groove, which can negatively affect the performance of the projectile, for example, its interaction with the rifling profile of a firearm barrel.

An object of the present invention is to overcome the disadvantages of the prior art, particularly to manufacture functional grooves in projectiles in a simpler manufacturing manner, thereby reducing the impairment of the projectile's performance by the functional grooves.

The object is achieved by the subject matter of the independent claims.

Accordingly, a projectile for ammunition, for example, with a caliber of at most 20 mm, especially of at most 13 mm, is provided. The projectile can be a full metal jacket or partial metal jacket projectile. The projectile can be made of brass (for example, CuZn30), copper, tombac (for example, CuZn10 or CuZn5), or steel, especially plated or coated steel. However, the projectile can also be made of aluminum or tin.

The inventive projectile comprises a projectile body that can be solid or at least partially hollow. The projectile body can have a projectile tail and a projectile front, which has an open cavity in the firing direction, bounded by a projectile wall. The projectile body has an outer surface oriented towards the surroundings. If the projectile body has a hollow section, the projectile body also has an inner surface that can be arranged on the projectile wall bounding the cavity.

According to a first aspect of the present invention, the inner and/or outer surface of the projectile body is provided with at least one circumferential and/or longitudinal groove that transitions into the adjacent inner and/or outer surfaces of the projectile body without a contour jump and/or has a radius of at least 0.05 mm, especially at most 0.1 mm. The circumferential and/or longitudinal groove, particularly its groove bottom, has a reduced diameter compared to the caliber of the projectile and the adjacent inner and/or outer surfaces of the projectile body. The groove can be, for example, a fully circumferential engagement groove for the case mouth. Longitudinal grooves extending in the longitudinal direction can be deformation and/or relief grooves. Preferably, the circumferential and/or longitudinal groove is introduced by grooving, particularly circumferential or longitudinal grooving. Due to the absence of contour jumps and/or the large radius of the groove, there is little material displacement on the projectile surface, which can lead to local hardness increases and material stresses. The grooves thus produced can also be manufactured at a higher production speed, increasing the cycle rate in the production of inventive projectiles, resulting in a more cost-effective projectile overall. The smooth transition of the projectile surfaces into the groove reduces the influence of the existing groove on the projectile's performance.

According to another aspect of the present invention, which can be combined with the previous aspects and exemplary embodiments, a projectile, particularly a full metal jacket or partial metal jacket projectile, for ammunition, for example, with a caliber of at most 20 mm, especially of at most 13 mm, is provided. The projectile can be made of brass (for example, CuZn30), copper, tombac (for example, CuZn10 or CuZn5), or steel, especially plated or coated steel. However, the projectile can also be made of aluminum or tin. The projectile comprises an at least partially hollow or solid projectile body with a circumferential groove arranged on its inner and/or outer surface, along which several radial projections extending in the longitudinal direction of the projectile, which can be referred to as flags, are arranged at a particularly constant distance from each other, and/or a longitudinal groove, along which several radial projections extending transversely to the longitudinal direction of the projectile are arranged at a particularly constant distance from each other. Particularly in the case of functional grooves that serve as holding or gripping grooves, for example, for the case mouth, the projections have a positive effect on the holding or fastening force. The spaced radial projections can achieve a form-fitting and/or force-fitting connection, especially with appropriately structured components to be connected. In the case of deformation grooves intended to achieve a desired deformation of the projectile, the deformation behavior can be finely adjusted with the help of the radial projections. For example, a predefined stepwise deformation can be achieved due to the different wall thicknesses along the groove and thus a resistance force against deformation.

In an exemplary embodiment of the inventive projectile, the radial projections have a width measured in the direction of extension of the groove of at most 0.2 mm and/or are dimensioned such that they protrude less than 0.03 mm over the adjacent inner and/or outer surfaces of the projectile body. This ensures that they do not negatively affect the projectile's performance, particularly, for example, barrel wear and/or the resistance to being pushed through the firearm barrel.

According to another aspect of the present invention, which can be combined with the previous aspects and exemplary embodiments, a tool, particularly a grooving tool, for introducing a circumferential and/or longitudinal groove into a projectile blank, especially a metallic projectile blank, to manufacture a projectile formed according to one of the previously described aspects and/or exemplary embodiments, is provided. The inventive tool can be configured to be used in an inventive device, particularly a grooving station, and/or to interact with a punch-die arrangement to groove the projectile blank.

The inventive tool comprises an elongated, particularly rotationally shaped, hollow body, especially a case body, for receiving the projectile blank. Alternatively, the hollow body can be inserted into a cavity of the projectile body. The hollow body can be at least partially adapted to the shape of the projectile blank, particularly formed complementarily to it. For example, the hollow body can comprise an ogive-shaped receiving area in which the projectile blank can be at least partially inserted and particularly held.

The hollow body has an inward or outward protruding, particularly circumferential, grooving nose. The grooving nose is configured to press the groove into the projectile blank. The grooving nose is particularly arranged in the area of the projectile blank reception of the hollow body.

According to another inventive aspect, the hollow body is longitudinally slit such that, when force is applied from the outside, if the grooving nose is arranged on the inside, or from the inside, if the grooving nose is arranged on the outside, the hollow body is particularly elastically deformable, particularly compressible or expandable, so that the grooving nose can press the circumferential and/or longitudinal groove into the projectile blank. During the deformation of the hollow body, an especially elastic deformation restoring force develops, causing the hollow body to be reusable and/or return to its original shape after a grooving process. The pressing force is exerted on the tool from the outside, and the slitting in the hollow body allows deformation of the hollow body so that the pressing force can be exerted or transferred to the projectile blank via the grooving nose to deform it, thereby introducing the circumferential and/or longitudinal groove. The inventive tool is characterized, among other things, by its simple construction and fewer individual parts. It can be integrated into a transfer tool or a station of a transfer press and used at a single, particularly inventive, grooving station. Due to the simple manufacturing application of the tool, high cycle rates can be generated, making the tool well-suited for mass production. Furthermore, the tool is characterized by its compactness. It is overall only slightly larger than the projectile blanks to be processed. The outer dimension of the tool is dimensioned to be 30-50%, particularly 35-45%, larger than the outer diameter of the projectile blank to be processed.

In an exemplary embodiment of the inventive tool, the hollow body has several longitudinally extending through-slits arranged at a particularly constant distance from each other and several bending wings separated by two through-slits each. The bending wings can be equally shaped and/or dimensioned. Each bending wing is bounded by two through-slits. The through-slits are understood to extend completely through the hollow body's outer surface to the inner surface, which bounds the cavity.

In another exemplary embodiment of the inventive tool, the through-slits extend from a particularly open groove end of the hollow body over at least 50%, particularly at least 60%, 70%, or 80%, of the hollow body's longitudinal extension to a respective slit base, at whose axial height a bending joint is defined, around which an associated bending wing is particularly elastically pivotable. In the circumferential direction of the hollow body, the slit bases of the through-slits and the bending joints of the bending wings alternate particularly evenly. When force is applied to the hollow body to deform it, so that the grooving nose presses the circumferential and/or longitudinal groove into the projectile blank, the bending wings pivot elastically around their respective bending joints.

In an exemplary further development of the inventive tool, the grooving nose is arranged in the area of the groove end. The through-slits can divide the grooving nose into several segments distributed in the circumferential direction. For example, the slitting of the hollow body with an internal grooving nose causes compression of the hollow body due to the force applied from the outside, so that the grooving nose segments particularly approach each other by the width of the through-slits. This movement amplitude of the bending wings in the area of the groove end, particularly in the area of the grooving nose, determines the depth of the circumferential or longitudinal groove.

In another exemplary embodiment of the inventive tool, the through-slits extend over at least 50%, particularly at least 60%, 70%, or 80% of the hollow body's longitudinal extension, so that an unslitted section is formed at both end sides, particularly opening sides, of the hollow body. The unslitted section can extend over at least 5% of the hollow body's longitudinal extension from the end face of the hollow body. An advantage of the hollow body design with two end-side unslitted sections compared to the fully slit design is that the hollow body has higher stability or strength, which particularly results in higher durability.

In another exemplary embodiment of the inventive tool, each through-slit ends on both sides in a respective slit base, at whose axial height a bending joint is defined, around which an associated bending wing is particularly elastically pivotable. Regarding the function of the bending wings and particularly the bending joint, reference can be made to the previous embodiments. Unlike the fully slit hollow body variant, the force applied from the outside to deform the hollow body is distributed over two bending joints per bending wing in the hollow body variant with end-side unslitted sections. Similar to the previous embodiment, the bending wings fundamentally work analogously to the functional principle of leaf spring elements.

In another exemplary further development of the inventive tool, each through-slit ends in two opposite slit bases, and the grooving nose is arranged in the range of 20% to 80% of a distance, particularly in the range of 40% to 60%, preferably centrally, between the two slit bases. Depending on the positioning of the grooving nose, the load on the respective bending joints can be adjusted or adapted.

In another exemplary embodiment of the inventive tool, the bending joints are manufactured in one piece with the associated bending wing. Particularly, the hollow body is fully manufactured in one piece, particularly from a piece of metal. The hollow body can, for example, be manufactured from a blank by turning with subsequent heat treatment and finished by grinding and possibly sinker EDM. Subsequently, the slits can be manufactured by wire EDM with a wire diameter of about 0.1 mm. For example, the bending joints are designed as film hinges and/or work at least according to the functional principle of a film hinge, without requiring a local wall thickness reduction compared to the rest of the bending wing.

In an exemplary further development of the inventive tool, the hollow body has a counter bearing, such as a particularly circumferential projection, particularly a ring projection, at about the axial height of the grooving nose, which can be acted upon with a force to deform the hollow body, particularly to preferably elastically pivot the bending wings particularly around their bending joints. The counter bearing can be designed as a defined stop for a punch-die arrangement, for example, of an inventive device, so that during a coordinated relative movement between the tool and the punch-die arrangement, the punch-die arrangement engages with the counter bearing, initiating the deformation of the hollow body.

According to another aspect of the present invention, which can be combined with the previous aspects and exemplary embodiments, a device, particularly a grooving station, is provided for introducing a circumferential and/or longitudinal groove into a projectile blank to manufacture a projectile formed according to one of the previously described aspects or exemplary embodiments.

The inventive device comprises a tool formed according to one of the previously described aspects or exemplary embodiments, such as a grooving tool, which has a grooving nose with which the circumferential and/or longitudinal groove can be introduced into the projectile blank. Regarding the tool, reference can be made to the previous embodiments.

Furthermore, the inventive device comprises a punch-die arrangement for holding the projectile blank.

According to another aspect of the present invention, the tool and the punch-die arrangement are coordinated and/or can interact such that the punch-die arrangement can elastically deform, particularly compress or expand, the tool to introduce the circumferential and/or longitudinal groove into the projectile blank. For example, the force necessary to deform the tool, which in turn causes the introduction of the groove into the projectile blank, is generated by the interaction of the punch-die arrangement with the tool.

In an exemplary further development of the inventive device, the die has a particularly form-adapted reception for the projectile blank, and the punch has a driver assigned to the tool such that during a particularly translational relative movement of the die and punch, the driver exerts a pressure or pressing force on the tool to deform it. The deformation of the tool, in turn, results in the force necessary for grooving the projectile blank, particularly the deformation force, being available. When using the inventive device, no rotating bearing of the projectile blank and/or a component of the device is necessary to groove the projectile blank; a translational relative movement between the punch and die is sufficient.

In another exemplary embodiment of the inventive device, the punch, particularly the driver, has a conical guide surface over which a continuously increasing pressure or pressing force can be generated. During the translational relative movement of the die and punch, particularly during the interlocking or disengaging of the punch and die, the driver increasingly wedges into an associated die surface with its conical guide surface, so that the force necessary to deform the projectile blank to introduce the groove, particularly the deformation force, is continuously built up.

According to another aspect of the present invention, which can be combined with the previous aspects and exemplary embodiments, a method for introducing a circumferential and/or longitudinal groove into a projectile blank is provided, particularly a grooving method, to manufacture a projectile formed according to one of the previously described aspects or exemplary embodiments.

In the inventive method, a projectile blank is inserted into an inventive tool, particularly an inventive device, and the projectile blank is locally grooved, particularly squeezed, by an especially elastic deformation, particularly compression or expansion, of the tool, forming the circumferential and/or longitudinal groove.

Preferred embodiments are indicated in the dependent claims.

In the following description of exemplary embodiments of the present invention, an inventive projectile is generally designated with reference numeral, an inventive tool for introducing a circumferential and/or longitudinal groove into a projectile blank is generally designated with reference numeral, and an inventive device for introducing a circumferential and/or longitudinal groove into a projectile blank is generally designated with reference numeral.

shows a schematic sectional view of an inventive device. The inventive deviceis used to manufacture an inventive projectile, which is also shown in.

The projectilecan particularly be a full metal jacket or partial metal jacket projectile. The projectilecomprises a projectile body, which has a cylindrical projectile tailand an ogival projectile nose. The projectile bodycan be solid or have an open cavity in the direction of the projectile tip, so that the projectile bodyis partially hollow. On the outer sideof the projectile, a circumferential grooveis pressed, which has a smaller diameter than the outer sideof the projectile. The circumferential groovecan be provided, for example, as an engagement groove for the case mouth of a case.

The devicefor manufacturing the inventive projectilefrom a projectile blank comprises the following main components: an inventive tooland a punch-die arrangement, which interacts with or is coordinated with the inventive toolto introduce the circumferential grooveinto a projectile blank. The punch-die arrangementcomprises a punchand a die, which are translatable relative to each other in a pressing direction P.

In, the dieis rotationally shaped and has two steps on an outer side, where the outer diameter of the diechanges abruptly. Viewed from a bottom sideof the dietowards a top sideof the diefacing the punch, a first stepserves as an axial support surface for the inventive tool. Further towards the top side, a second stepis provided, resulting in an air gapbetween the outer sideof the dieand the inventive tool, allowing the inventive toolto be compressed radially, transverse to the pressing direction P, and elastically deformed or compressed. Between the stepand the step, the inventive toollies flat against the outer sideof the dieand is thus fixed to the diein the pressing direction P and radially. On the top sideof the die, a receptacleis formed to hold the projectile blank or the finished projectile. The receptacleis adapted to the shape of the projectile noseand is thus ogival in shape.

The punchis also rotationally shaped inand has a cavityon a front sidefacing the die. The cavityand a wallof the punchbounding the cavityare dimensioned such that at least one side of the toolfacing the punch is received in the cavityand compressed radially by the wallwhen the punchis moved further in the pressing direction P towards the die, and the punchand the dieinterlock. Starting from the front side, the cavityis initially formed by a conical wall sectionand then transitions into a cylindrical wall section. Through the conical wall section, a continuously increasing radial pressure force is exerted on the toolduring a movement of the punchin the pressing direction P. The conical wall sectioncan thus be referred to as a conical guide surface.

The following describes the structure of an inventive toolfor introducing a circumferential groove into the outer sideof a projectile blank based on the exemplary embodiment in.

The toolcomprises an elongated sleeve-shaped hollow body, which is made in one piece, for example, from metal. The hollow bodyis hollow cylindrical and has a hollow body wallwith a constant wall thickness, which bounds a cylindrical cavity. The wall thickness can be, for example, about 2 mm. At an end faceor a groove endof the hollow body, a circumferential grooving noseis formed, which protrudes from the hollow body wallinto the interior of the hollow body. For example, the grooving nosecan protrude about 4 mm radially into the interior of the hollow body, perpendicular to the longitudinal direction L of the tool. In the embodiment in, the grooving nosehas a roundingat the end, so that a groove with a round cross-section can be produced.

The hollow bodyhas several through-slitsoriented in the longitudinal direction L. The through-slitsextend radially completely through the entire hollow body walland through the grooving nose, dividing it completely into several separate segmentsin the area of the grooving noseand bending wingsin the area of the hollow body wall. In other words, the through-slitsextend over the entire wall thickness of the hollow bodyfrom an outer side of the hollow bodyto an inner side of the hollow body. In the longitudinal direction L, the through-slitsextend from the groove endfor at least 50% of the longitudinal extension of the hollow bodyand end in a slit base. At the axial height of the slit bases, each bending winghas a bending joint. Since the hollow bodyis made in one piece, the bending jointsare each formed in one piece with the associated bending wingand are designed as film hinges. When the toolis compressed at the groove endor in the area of the grooving nose, the bending wingsare each elastically pivotable around their associated bending joint. At an end of the hollow bodyopposite the groove end, an unslitted sectionis provided, with which the toolinrests against the dieof the inventive device.

In the exemplary embodiment in, a total of 20 through-slitsand thus 20 bending wingsare formed, which are evenly distributed in the circumferential direction and arranged at a constant distance from each other. The bending wingsare each bounded in the circumferential direction by two through-slitsand are all equally dimensioned and shaped. It is clear that more or fewer than 20 through-slits can also be provided. Preferably, between 12 and 36 through-slits can be provided. For example, the width of the through-slits can be between 0.05 mm and 0.1 mm.

To introduce a groove into a projectile blank, the projectile blank is inserted from the groove endof the toolin the longitudinal direction L into the cavityof the hollow bodyuntil the point of the projectile blank where the groove is to be introduced is positioned in the longitudinal direction L at the axial height of the grooving nose. When force is applied from the outside, the bending wingselastically pivot around the respective bending jointand are elastically deformed or compressed, so that the segmentsof the grooving noseare compressed radially and approach each other by the width of the through-slits. As a result, the segmentsof the grooving nosepress into the projectile blank material and press the desired groove. Thus, with the inventive tool, no rotation between the tooland the projectile blank is necessary to groove the projectile blank. Once the external force no longer acts, the bending wingsreturn to their original shape due to the deformation restoring force generated by the elastic deformation, and the finished projectilecan be removed from the tool.

For a projectile blank with a cavity in the projectile nose, it can also be provided to introduce a groove on the inside of a wall bounding the cavity of the projectile blank. The inventive tool is then inserted into the cavity of the projectile blank. The grooving nose is arranged on the outer side of the slit hollow body in this embodiment and preferably protrudes outward perpendicular to the longitudinal direction. To press the groove, a force is applied from the inside to the tool, for example, with a conical punch, so that the bending wings elastically expand and introduce an internal groove into the projectile blank on the inner side of the wall.

shows another exemplary embodiment of an inventive tool. The toolindiffers from the tool inin that a radially outwardly protruding, circumferential projectionis provided at the end of the hollow body, leading to a larger support surface of the toolon the dieof an inventive deviceand additionally providing a support surfacefor further components of the deviceopposite the end of the hollow body. The toolalso differs in that a counter bearingin the form of a circumferential ring projection is provided at the axial height of the grooving nose, at the groove end. In this embodiment, the force from the outside to elastically deform the toolis applied to the ring projection. The ring projectionserves as a defined stop, for example, for the punch-die arrangement. The toolalso differs in that the end of the grooving nosedoes not have a rounding but a flat surface. Thus, a groove pressed with the toolaccording to the embodiment inhas a rectangular cross-section.

shows another exemplary embodiment of an inventive tool, which differs from the previous embodiments in that an unslitted sectionis also provided at the end faceof the hollow body. Both unslitted sectionsextend for more than 5% of the longitudinal extension of the hollow bodyfrom the respective end of the hollow bodyin the longitudinal direction L towards the middle of the hollow body. The through-slitsin this embodiment each end in two opposite slit bases. Each bending wingthus has two opposite bending jointsin this embodiment. The through-slitsare arranged centrally in the longitudinal direction L on the hollow bodyin this embodiment and extend over at least 50% of the longitudinal extension of the hollow body. The grooving noseand the supportare arranged in this embodiment in the longitudinal direction L in the middle between the two slit bases. Due to the additional unslitted sectionat the end faceand the two bending jointsper bending wing, the hollow bodyhas higher stability or strength, which increases the durability of the tool.

show another embodiment of an inventive device, with the deviceshown inbefore introducing a circumferential grooveinto a projectile blankand induring the introduction of the circumferential groove. The devicecomprises, like the device in, an inventive tool, a punch, and a die.

The dieessentially corresponds to the diefrombut differs in that only one stepis provided on the outer sideof the die, on which the toolrests. The reason for this is that the toolused inhas a ring projectionin the area of the grooving nose, and thus an air gap already exists between the tooland the outer sideof the die, allowing elastic deformation of the tool, so no further step is needed.

The diestands on a base plateof the devicein this embodiment. Additionally, a receptaclewith a cylindrical through-bore, in which the dieand the toolare arranged, is fastened to the base plate, for example, with screws. Two steps are provided in the through-bore, where the diameter of the through-borechanges abruptly. A first step, viewed from the direction of the base plate, serves to fix a holderfor the dieand the tool. The holderrests on the projectionof the tooland thus presses the tooland the dieagainst the base plate. A springrests on the holder, which biases a pressure pieceagainst the pressing direction P. The movement of the pressure pieceagainst the pressing direction P is limited by a second stepof the through-bore.

To introduce a circumferential grooveinto the projectile blank, the projectile blankmust first be placed in the receptacleof the die. For this purpose, a two-part punchis provided, which rests on the top and bottom of the projectile blank and is movable in the pressing direction P relative to the dieand the punch. When the projectile blankis in the receptacle, the punchis moved in the pressing direction P towards the die. The punchthen presses with the front sideagainst the pressure pieceand moves it against the biasing force of the springin the pressing direction P. As a result, the pressure pieceis pushed over the tooland compresses it radially. As explained regarding, the grooving noseof the toolthen presses a circumferential grooveinto the outer sideof the projectile blank.