METHOD FOR PRODUCE SLEEVES FROM MULTI-COMPONENTS

Description

Introduction and scope of the invention

[0001] The manufacture of bullet casings, for example for firearms, has been done throughout the world for more than a century by the mechanical deformation of a single piece of metal made of brass, steel or other alloys.

[0002] The manufacturing processes associated with this production method include numerous stamping, deep drawing, pressing and stretching operations, to name only the main ones, which are interspersed with heat and / or chemical treatments designed to relax the stresses generated in the material being treated and remove the oxidation produced in some cases by the heat treatment.

[0003] The significant manufacturing resources required involve large presses, heat treatment facilities, chemical treatment facilities, machining equipment, and transfer and feeding systems.

[0004] These manufacturing methods have many drawbacks. Investments are significant, chemical treatments require water pollution control measures, and facilities are often designed for specific calibers. These manufacturing processes do not allow for the production of cases with uniform wall thickness, as would be possible with the manufacture of multi-component cases, for example, those illustrated in the... figures 6 to 10 using thin strips, assembled using welding processes or well-known mechanical processes that are simpler to implement.

[0005] Document EP2552619B1 describes a process for manufacturing a cartridge sleeve by cold forming pipes with or without welding. Principle of the present invention

[0006] One aim of the invention is to improve the manufacturing processes of bullet ammunition casings and to produce thin-walled casings that are lighter and offer a larger internal volume, allowing for an increased amount of propellant and thus a greater range.

[0007] More specifically, one aim of the present invention is therefore to propose simple, efficient and above all less expensive manufacturing methods for bullet ammunition casings made by assembling two or more elements produced in an optimized way.

[0008] Another objective of the present invention is to simplify the handling of the elements used and to reduce the handling of unit elements, as is necessary in common installations to feed presses and other machining stations.

[0009] Another objective of the present invention is to significantly reduce the investments required for the manufacture of bullet ammunition casings while maintaining high production rates.

[0010] According to one embodiment, the invention relates to a method for manufacturing bullet ammunition cases, said case comprising at least one main part called the body but which we will also call the "jacket" of conical shape, a shoulder, a tip and a base, method in which the jacket and / or the shoulder and / or the tip is (are) formed from at least one thin strip by shaping said strip or said strip(s) on a die (also called an insert) reproducing at least the characteristic taper and / or shoulder and / or mouth of the case.

[0011] In one embodiment, the shirt, shoulder and mouthpiece are formed from the same strip or piece.

[0012] In one embodiment, the jacket, shoulder, and mouthpiece are formed from different strips or pieces. The materials of each strip or piece may or may not vary.

[0013] In one embodiment, the strip or part before forming has the shape of a tube.

[0014] In one embodiment, the tube is formed from a flat strip that is shaped into a tube.

[0015] In one embodiment, the tube-shaped strip is closed by a weld made by welding means such as electron beam, laser or other equivalent. According to the invention, a plurality of die(s) are slid and fitted into one another in the tube forming the sleeve of the socket before shaping.

[0016] In one embodiment, the tube is shaped by mechanical and / or electromagnetic and / or pneumatic and / or hydraulic means.

[0017] In one embodiment, the shape of the die and the spacing with the next die are designed in such a way that the wall thickness at the mouth of the socket can be controlled.

[0018] In one execution mode, the dies or inserts may be composed of different elements, these elements may be of different materials and some elements may have radial or longitudinal clearances adapted to the welding modes.

[0019] In one embodiment, the material of the strip can be stainless steel, normal steel, brass, aluminum, an alloy or other equivalent material etc...

[0020] In one embodiment, the sleeve is made by welding two half-shells, each being a formed part.

[0021] In one execution mode, the half-shells retain their stamping edges.

[0022] In one execution method, the half-shells are stripped of their stamping edges immediately after welding.

[0023] In one embodiment, the half-shells are made from strips of various materials such as stainless steel, normal steel, brass, aluminum for example.

[0024] In one embodiment, the half-shells are welded together by one of the known welding methods, such as electron beam, laser, etc.

[0025] In one embodiment, the stamping edges are removed by mechanical cutting, water jet cutting, deburring, or any other known cutting method.

[0026] In one embodiment, the tube forming the body of the socket is assembled to its base and then placed in an axial stamping machine equipped with a concentric gauge forming a die / insert and ensuring the internal diameter of the opening, and a counter-form actuated, for example, by a press to deform the tube and give it the characteristics of the final socket.

[0027] In one embodiment, the tube forming the body of the socket is placed on a punch with suitable shapes equipped with a concentric gauge forming a die / insert and ensuring the internal diameter of the mouth and stamping the tube by means of a counter-form operated, for example, by a press to deform the tube and give it the characteristics of the final socket.

[0028] In one embodiment, the shaping operation includes tapering and / or shoulder and / or tubular mouth.

[0029] In one embodiment, the invention relates to a casing, for example a firearm ammunition casing, obtained by a process as described in this application. Detailed description of the present invention

[0030] Embodiments of the present invention are now described with reference to the figures shown. There figure 1 illustrates a perspective view of the principle of the invention according to a first embodiment. Figure 1b illustrates known means for implementation according to the first embodiment of the invention. figure 2 illustrates a schematic perspective view of the principle of the invention according to a first embodiment. figure 3 illustrates a schematic perspective view of the principle of the invention according to a first embodiment. figure 4 illustrates a perspective view of the principle of the invention according to a second embodiment. Figure 5illustrates a perspective view of the principle of the invention according to a second embodiment. figures 6 to 10 illustrate perspective views of various embodiments of the invention. Figures 11 and 12 illustrate, in perspective, one method of implementing the invention. figure 13 illustrates a process according to a method of executing the invention.

[0031] In a first embodiment, the present invention consists in particular of first manufacturing the main part of the socket, called the body but which we will also call the "jacket", by shaping a thin tube 2 on rigid forms 1a representing the internal volume as well as the shoulder and the mouth of the socket also called the collar.

[0032] Then, after extracting conforming elements or shapes (referred to interchangeably as "matrix" or "insert" in this application) 1a, to assemble said formed liner with a base 6, designed for this purpose, by a well-known welding or mechanical assembly process.

[0033] One of the distinctive features of the present invention is that the liners are formed not one by one, but in long chains of several dozen, or even more than a hundred, pieces / sleeves, which are shaped and then individualized by cutting. The chains are processed individually and then used to feed the stations responsible for separating the elements, extracting the inserts 1a, presenting the bases 6, and welding them to the liners 5. This eliminates the need to load these machines individually and simplifies the necessary equipment.

[0034] In a first possible execution mode illustrated in the figures 1, 2 and 3 The inserts 1c are slid into the tube 2 using a special insertion guide 3, while the tube undergoes a rolling operation that transforms it from a flat strip (called a "strip") into a nearly closed cylinder (as illustrated in Figure 1a, which is taken from the Larousse dictionary and shows how such a cylinder can be formed using rollers). The inserts 1c are designed to interlock with each other and form a continuous chain. If necessary, the main parts of the inserts 1a may have a small groove to reduce the impact on the electron beam welding, laser welding, or other equivalent process used to close the tube. This groove is illustrated in detail "D" of the figure 1 In such a case, the insert insertion device can advantageously be equipped with a guide allowing for their proper alignment.

[0035] The operation described above can also be performed by inserting the 1c inserts into a long, thin, already closed and welded tube. In this case, sufficient clearance must be provided between the inserts and the closed tube to avoid applying significant insertion forces that could damage the latter.

[0036] Tube 2 is initially closed by a known welding process, such as electron beam welding, laser welding, or another equivalent process. The closed tubes filled with inserts 1c are then fed into a forming machine that forces the wall of tube 2 against the inserts 1c to produce the slight taper, shoulder, and mouth characteristic of ammunition casings 4. This forming operation can be carried out by mechanical, electromagnetic, or hydraulic means, to name just a few non-limiting examples. This operation is illustrated in the figure 2 particularly by the arrows placed around tube 2. Once all the tube elements have been formed, a separation operation can be carried out by cutting, for example using a circular saw illustrated by detail E (in the figure 3), of the tube at the height of the base of each insert 1c. The collar 5b and the conical washer 1b are thus removed, and the element comprising the "sleeve" 5 and its insert 1a are transferred to a special installation which will eject the insert 1a, then assemble the socket "sleeve" 5 to its base 6, before passing them through a base and "sleeve" welding station and finally through a cutting station to the length of the mouth to form a complete socket 7. These operations are illustrated in particular in the figure 3 .

[0037] Depending on the design of the base 6, it may already include an ejection groove. Otherwise, this groove can be machined in a dedicated machining station; see the Figures 11 and 12 .

[0038] In this embodiment, the inserts 1c are composed of two concentric parts: one 1a, which forms the internal shape of the "jacket," and the other 1b, which is conical in shape, designed so that during the shaping of the tube 2 by one of the aforementioned processes, it is possible to control the variation in wall thickness caused by deformation. The two-part composition of the inserts 1c allows the main part 1a to be preserved during the separation of the shapes.

[0039] While welding methods are applicable to all types of materials, electromagnetic welding is limited to conductive metals and is not suitable for all stainless steels. Limitations also exist for combinations that may cause electrolysis or other undesirable phenomena. Therefore, depending on the circumstances and the materials used, the appropriate process can be selected.

[0040] In another approach to manufacturing multi-component sockets according to a second execution method (illustrated in the Figures 4 and 5 ), it is also possible to proceed by stamping half-shells 10a and 10b of the figure 4 exhibiting the characteristic taper, shoulder, and mouth of ammunition casings, this method also produces a stamping from a flat sheet or strip, for example, of metal. Such stamping is easily achieved with common tools adapted to the desired shape. In this method, one starts with a flat sheet rather than a sheet shaped into a tube, as in the first method, but using a similar process, the sheet is brought into its final shape (a tube for the first method, a half-shell for the other methods), for example, by stamping between a punch and a die having the desired shapes.

[0041] The half-shells 10a and 10b can then be assembled using well-known welding methods such as electron beam, laser, etc.

[0042] In another possible mode of execution ( figure 4 The half-shells 10a and 10b can be separated from the stamping edges 12a and 12b and brought together edge to edge for welding using a suitable mechanical device. The resulting "sleeves" 11 can then be housed in a storage device allowing for easy feeding of subsequent workstations.

[0043] In another possible mode of execution ( Figure 5 ), the stamping edges 22a and 22b of the half-shells 20a, 20b of the Figure 5can be held and serve as a link between the welded parts. The resulting sequence can facilitate winding the parts onto well-suited drums, offering both intermediate storage and a means of supplying subsequent workstations. The stamped edges 22a and 22b can be detached from the half-shells 20a, 20b during the assembly operation of the sleeve 5 with the base 6 to form the bushing 7. This process also applies to the embodiment of the figure 4 .

[0044] In these modes of execution, we can also use forms 1a as in the first mode to ensure good alignment of the two half-shells 10a and 10b (20a, 20b) when they are fixed to each other.

[0045] In another mode of execution, schematically represented by the figures 6 to 10It is also conceivable to produce the socket 7 by assembling two or more individual elements, each having been previously formed (or shaped) so that the final step of the process is simply an assembly of prepared and formed parts: a machined base 6, a conical tube 5, a shoulder 5c, a cartridge tip 5d, as shown in the Figure 9a , or a shoulder with a 5e cartridge tip, to name only the main combinations that welding processes or well-known mechanical processes allow.

[0046] In another execution, which is schematically represented in the Figure 9b The shoulder 5c can advantageously be equipped with centering elements 5f to easily align the conical body 5c and the sleeve 5a for easier assembly. The same can be done for the end piece 5d to facilitate its assembly with the shoulder 5c.

[0047] Among the assembly methods that can be taken into account, we can mention, without being exclusive: electron beam welding, plasma welding, friction welding, brazing and crimping etc... and other equivalent processes allowing the assembly of parts of various shapes and materials.

[0048] Preferably, in the described embodiments, the cylindrical socket body 5 is formed from a metal strip 2 which is rolled into a tubular shape, the two adjacent edges of the strip then being joined together, for example by welding. Other variations are possible as described and illustrated in this application. The materials used for the various parts are preferably, but not exclusively, metals.

[0049] In another embodiment, the tube 2 forming the body of the socket 5 can be pre-shaped axially to present one or all of the characteristics of the final socket 7: taper, shoulder and mouth intended to receive the projectile.

[0050] In this example of an embodiment of the present invention, a first step, illustrated in the figure 11 The process is carried out by assembling, using known welding or mechanical processes, a socket body, formed from a thin-walled tube 2, and a base 6 consisting of a cylindrical washer. In this way, a socket blank is produced in a single operation, which normally requires several operations of forging and / or drawing, heat treatment, and chemical treatment. This blank can then be axially shaped according to conventional processes for forming the taper, shoulder, and tip of sockets, as illustrated in the upper sequence of the figure 13The punch 26 ensures the internal diameter of the mouthpiece, while the counter-form 27 produces the taper, shoulder, and mouthpiece to create a complete socket. The drawing at the top of the figure 13 illustrates the "traditional" steps of axial forming. Thus, step 1 is the fixing of the tube 2 and the base 6, steps 2 and 3 the insertion of the gauge 26 into the tube 2 assembled with the base 6, step 3 the lowering of the counter-form 27 to deform the tube 2 and give it the desired conformation (step 5) and in 6 the removal of the counter-form 27 and the gauge 26.

[0051] In an execution using similar processes, for example, as illustrated by the successive stages of the figure 13(bottom drawing), the tube 2 forming the body of the socket is inserted onto a die 25 with suitable shapes representing the internal taper and shoulder of the socket. A concentric gauge 26 forming an insert (as described above) ensuring the internal diameter of the mouth is inserted into the die 25 before the tube 2 is stamped by means of a counter-form 27 operated by a press to deform the tube 2 and give it the characteristics of the final socket liner 5. An extractor, not shown in the drawing, allows the formed socket liner 5 to be extracted from the die 25. This forming operation may include the taper 5a, the shoulder 5c and the tubular mouth 5d or be limited to the taper 5a and the shoulder 5c or even limited to the taper of the socket 5a alone (see in Figures 6 to 10 ). These operations can also be carried out by other mechanical means acting, for example, radially as described above.

[0052] In an execution mode (illustrated in figure 12 The cylindrical washer 6, which forms the base of the cartridge case 2, may be provided with an ejection groove 6a and a recess for receiving the primer 6b, as well as an optional shoulder 6c to facilitate centering the case body 2. Such operations can be carried out, for example, using well-known turning, stamping, or machining processes on the initial cylindrical washer and can easily be automated.

[0053] Of course, the process of the figure 13 can be applied to tube 2 to form the one-piece socket or to socket parts that will then be assembled (see the figures 6 to 10 and the description above).

[0054] The embodiments of the invention are given by way of illustration and should not be considered limiting. They may be combined with each other or make use of equivalent means depending on the circumstances.

[0055] Any suitable material can be used for the initial sheet / strip and parts of the socket: stainless steel, normal steel, brass, aluminum, alloy(s) or any other equivalent material suitable for the object to be made, etc.

[0056] The cartridge case can be of any caliber and for use in any type of weapon without limitation.

Claims

1. A method for manufacturing bullet ammunition casings (7), said casing comprising at least one tapered main portion constituting a jacket (5, 5a), a shoulder (5c), a mouth end (5d, 5e) and a cup (6), method in which the jacket, the shoulder and the end piece are formed from at least one thin strip by shaping said strip(s) on a die reproducing the taper and the shoulder and the mouth characteristic of the casing, characterized in that the strip before shaping has the shape of a tube (2) and that a plurality of dies (25) are slid and interlocked into each other in said tube before the shaping.

2. The manufacturing method according to the preceding claim, wherein the jacket (5, 5a), the shoulder (5c) and the mouth end (5d, 5e) are formed from the same strip.

3. The manufacturing method according to claim 1, wherein the jacket (5, 5a), the shoulder (5c) and the mouth end (5d, 5e) are formed from different strips.

4. The manufacturing method according to any of the preceding claims, wherein the tube (2) is formed of a planar strip which is shaped as a tube.

5. The manufacturing method according to the preceding claim, wherein the strip shaped as a tube (2) is closed by a weld carried out by welding means such as an electron beam, laser or the like.

6. The manufacturing method according to any of the preceding claims, wherein the tube (2) is shaped on the die by mechanical, electromagnetic, pneumatic or hydraulic means.

7. The manufacturing method according to any of the preceding claims, wherein the shape of the dies (25) and the spacing with the following die are designed in such a way that the thickness of the wall at the level of the mouth (5d, 5e) of the casing (7) can be controlled.

8. The manufacturing method according to the preceding claims, wherein the dies are composed of different elements and that some of said elements include radial or longitudinal clearances adapted to the welding modes.

9. The manufacturing method according to any of the preceding claims, wherein the material of the strip is made of stainless steel, normal steel, brass, aluminum, or an alloy of one of these materials or another equivalent material.

10. The manufacturing method according to any of the preceding claims, wherein the tube forming the body of the casing is assembled to its cup and then it is placed in an axial stamping machine, equipped with a concentric gauge (26) forming a die / insert and ensuring the internal diameter of the mouth and a counter-form (27) actuated by a press to deform the tube and give it the characteristics of the final casing.

11. The manufacturing method according to any of claims 1 to 9, wherein the tube forming the body of the casing is placed on a punch with suitable shapes equipped with a concentric gauge (26) forming a die and ensuring the internal diameter of the mouth (5d, 5e) and by stamping the tube by means of a counter-form (27) actuated by a press to deform the tube and give it the characteristics of the final casing.

12. The manufacturing method according to the preceding claim, wherein the shaping operation comprises the taper, the shoulder and the tubular mouth.