EP3111156B1 - Cartridge ammunition comprising multiple lead-free projectiles interconnected by a metallic line - Google Patents

Description

The present invention belongs to the field of ammunition used in hunting or shooting weapons, and more particularly to that of cartridges whose offensive charge consists of multiple projectiles, shot type.

Its object is an offensive charge consisting of multiple projectiles formed of grains mechanically bonded to each other by a wire, which does not contain lead. Another object of the invention is a cartridge for firing, incorporating such projectiles. A method of mass-producing these lead-free projectiles is also claimed.

For small game hunting such as duck hunting, the goal is to stop and quickly kill the moving animal. In this case, shotgun shots are fired from multiple, unimposed projectiles to increase the chance of hitting, limiting the range to protect property and people in the direction of fire.

Hunting and firing cartridges are known to consist of several components that perform different functions from one another. The shell of the cartridge (sleeve) generally cylindrical, contains a propellant charge (powder) at one end and an offensive charge (shot or sinkers), separated by a flock. The wad performs two distinct functions: it retains the gases produced by the explosion and it puts pressure on the shots by pushing them neatly out of the barrel of the weapon. A conventional hunting cartridge contains from 30 g to 35 g or 36 g of projectiles, called lead shots, ie 200 to 300 small diameter lead pellets, which is generally between 1 mm and 4 mm, in particular between 1.25 mm and 4 mm. They are distinguished from much larger chevrotines, which designate cartridges with fewer than 28 projectiles ranging in diameter from 5.65 mm to 8.65 mm, and which are prohibited for hunting in most French departments.

In addition, it is known from the document US 3,085,510 , to use as an offensive charge for a firing cartridge a set of at least two lead grains interconnected by a rope, preferably a monofilament wire such as those used in fishing activities, so as to improve the kinetic properties of the projectile thus formed. Lead shot has long been used as a projectile in shot and shot cartridges to increase the probability of hitting a small moving target. More broadly, heavy metals (high density metals) have been used in most munitions to improve the kinetic characteristics of projectiles. However, all these metals are toxic, particularly lead, which is generally added 1% to 8% of arsenic, also toxic. This toxicity manifests itself on several levels: during accidents during manufacture; by the pollution accumulated on the manufacturing sites that are responsible for lead poisoning; when in use, direct health problems arise from the emission of lead vapors; and when destroying unused ammunition.

That is why many countries have, since the 1980s, banned or reduced the use of lead in hunting cartridges, in favor of less toxic cartridges, so-called non-toxic. This applies primarily to hunting waterfowl in wet and phreatic areas.

We have therefore tried to replace the projectiles lead by other materials. In the first place, steel shots have been proposed. However, if steel has the advantage of being inexpensive, it is however much harder than lead (it can be considered indeformable at the scale of constraints that interests us). This hardness poses problems of resistance of the gun barrel. Indeed, with a hard material, the shot charge forms a packed and resistant assembly that causes a blasting of the surface at the cone connection between the chamber of the gun accommodating the sleeve of the cartridge and the barrel. There is also degradation of the barrel by swelling or even bursting. The steel is also light (its density is between 7.3 and 8.0 against 11.35 for pure lead), which gives it a significantly lower kinetic energy with equal propellant charge.

A metal such as tungsten, heavier than steel, is significantly more expensive, of the order of 10 times, which disqualifies it for mass production. As for the use of bismuth, if it is not explicitly forbidden, it is to be banned since it is even more toxic than lead.

It has otherwise been proposed by the prior art, illustrated in particular by the document WO 93/22089 , projectiles formed of grains consisting of alloys of metal compounds to reduce toxicity in comparison with lead grains by combining a high melting metal compound with a low melting point metal compound such as tungsten and tin, respectively. These alloys are further constituted so as to obtain projectiles of density comparable to that of lead, to reproduce the kinetic properties of the projectiles lead. Also US5,513,689 , seeking to replace lead ammunition turned to bismuth and its non-toxic alloys, because of their density close to that of lead.

We can finally quote EP 655,604 which refers to a bullet made of tin alloy and another metal to replace in the lead ammunition by non-toxic materials, However, these alloys which have a density much lower than that of lead, have property unsatisfactory ballistics.

It can be stated that up to now no satisfactory solution has been found for producing non-toxic multiple projectile cartridges with characteristics as interesting as lead shots and having performances equivalent to those of lead shots, point of view of the range, the piercing power and the deformation with release of energy.

Thus, according to an object of the present invention, it is sought for an ammunition for hunting waterfowl, ie a cartridge without lead in accordance with legislation applying to wetlands. Another object of the invention is to define a component for cartridges, namely a projectile devoid of lead and yet having properties comparable to those of conventional projectiles lead. The present invention responds to this need by proposing a multiple projectile for a firearm, and particularly for smooth-bore weapons, which perfectly meets these specifications. In particular, this objective is achieved through the choice of a very specific metal composition to manufacture the grains of the projectile, with a mechanical connection of several grains between them.

Yet another object of the invention is to provide a method of mass production of such projectiles, which is economically acceptable.

At the origin of the invention, it has been found by the present inventor that the crucial point for reproducing the performance of lead-based projectiles is not, as the suggestion suggests the prior art, to seek to approach, by the alloy implemented, as much as possible of the density of lead, but rather to prefer that the alloy has a hardness close to that of lead. The question of a difference in density can be regulated by the number of grains connected by the same wire, such a determination falling within the skill of the person skilled in the art. It has thus been found by the present inventor that the reproduction of the hardness of the lead conditions primarily obtaining alloy projectiles adapted to reproduce the performance of the projectiles lead.

Thus, it is now proposed by the present inventor an offensive charge for the manufacture of a cartridge for firing with a firearm, composed of multiple projectiles formed by grains formed of at least two substantially spherical grains connected together. by a metal wire of predetermined fixed length, the grains being based on tin, which has no known toxicity to the environment. However, tin being very malleable (or pasty), and hardness lower than lead, it can not be used alone. To obtain a hardness close to that of lead, it is possible to use an alloy of tin with another compound. The second component of the alloy of the grains will be chosen from among those which are not toxic and which are miscible with tin at least in certain proportions, which will be combined with tin to obtain an alloy assimilable to a soft metal, that is to say having a hardness equivalent to that of lead or a composition containing more than 80% of lead. The choice was antimony, to obtain small metal grains, non-toxic, of adequate hardness.

In one embodiment of the offensive charge according to the invention, the alloy of the grains is composed, for at least 99%, of tin and antimony. All proportions will be given below in mass content.

According to an advantageous characteristic of the invention, the alloy of the grains preferably comprises from 90% to 98% of tin, and / or from 2% to 10% of antimony.

Preferably, a composition including about 5% antimony in about 95% tin is employed.

The projectiles according to the invention advantageously have characteristics as interesting as the conventional projectiles of lead, in terms of hardness on the one hand, so that a crash of the projectile on a target releases a large amount of the energy that has provided by the explosive charge of the firing cartridge; and in terms of mass on the other hand, this last characteristic being ensured by the fact that, although the density of the alloy according to the invention is lower than that of lead, the grains are interconnected within the projectile. Thus, the density of tin is of the order of 7.3, that of antimony 6.7, the density of this alloy meeting the above characteristics is of the order of 7.25 to 7 29. Such an alloy will also be much less heavy than the lead at the same volume. This low density therefore appears to be insufficient to obtain a penetrating power (and therefore an effective range) similar to that of lead grains. To overcome this drawback, several grains are connected together, so as to form small clusters of larger mass.

However, the practice of this idea still had to overcome a number of obstacles: if it is known to connect buckshot grains by piercing them, then threading them on a lead wire and ligating the whole by twisting the However, this method can not be used for small grains, for both technical and economic reasons.

Technological difficulties in manufacturing due to the small diameter of the projectiles used for hunting waterfowl have been overcome. A method has been developed, which is part of the present invention, and allows the manufacture of bunches of small grains of a non-toxic alloy of tin and antimony, connected by a wire, also non-toxic .

As previously stated, according to a first aspect, the invention thus relates to an offensive load for the manufacture of a cartridge for firing with a firearm, composed of multiple projectiles, which projectiles are formed of at least two substantially spherical grains interconnected by a wire of fixed predetermined length, said grains being made of an alloy comprising tin and antimony. The grains (or shot) are almost spherical, as are the conventional shot pellets. The bonding wire is also of a metallic nature. It is strong enough to withstand tensions or tersions during filling and packaging cartridges.

The grains are gathered in clusters of two, three or four or more, using a wire. We thus obtain projectiles of two or more solid grains, whose quantity of motion at a given speed is a multiple of the quantity of motion that the grains taken in isolation would have. The number of impacts is reduced, but the kinetic properties are more powerful, so that the shot is more effective. It has been found that, for a two-grain bonded projectile, for example, there will be an effective firing distance doubled with respect to a load of unbound grains of the same alloy.

If you fill a cartridge with balls made of a tin-antimony alloy such as recommended by the present invention, we will have a lower mass than with the same volume of lead pellets. For example, for a volume of lead pellets of 36 grams, there will be an identical volume of alloy grains weighing a total of about 24 grams, but each projectile is one and a half times heavier than lead pellets. Finally, in this example the effective firing distance will be multiplied by 1.5. The low density of tin and antimony has been compensated for by binding the grains together.

The grains, which preferably contain at least 99% tin and antimony, may also contain, for example at most 1% (by weight) of a component other than tin and antimony. In the offensive charge according to the invention, the alloy of the grains may for example further comprise at most 1% of a third metal, excluding lead or other toxic metal, of course. This does not significantly modify the properties of the tin-antimony alloy. This embodiment has the main advantage of reducing raw material costs without affecting the desired qualities of the offensive load.

According to a particularly preferred embodiment of the invention, the alloy of the grains is composed of 94.5% tin, 5% antimony and 0.5% copper. This ternary alloy offers an ideal compromise in terms of the kinetic properties of projectiles and costs.

The length of the wire separating (and uniting) two adjacent grains is defined in advance during the manufacture of the bunches of grain. The grains are further associated with the wire so that the distance between them remains fixed after their manufacture, when they are put in cartridge and during firing. The mode of association could be physical (for example by pinching the wire in a notch made in the grain) but according to the invention it is of a chemical nature, that is to say by fusion of the wire and the grain, as we will see in detail later. According to another advantageous characteristic of the invention, the connecting wire between two grains is a brass wire, with a length of between 0.5 mm and 10 mm. Brass, which is an alloy based on zinc and copper, is chosen from those which are devoid of lead. The brass connecting wire will contribute to the density of the projectile. It is flexible enough not to break under the effect of the acceleration when fired and robust enough to withstand the passage in known type of packaging machines. The length of the wire between two grains is such that the grains form a relatively compact projectile, and are close enough to avoid frond-like springback phenomena.

According to the invention, the projectile preferably comprises two grains of diameter less than or equal to 4 mm bonded together. This conformation makes it possible to compensate for the relatively low density of tin. The assembly by two optimizes both the mechanical properties, kinetics and the number of impacts obtained from the firing of a cartridge.

The projectiles as defined above are particularly suitable for hunting waterfowl, but also for any other type of game, where cartridges adapted to smooth-bore weapons are used. Therefore, is also an object of the present invention a cartridge for firing with a firearm, comprising a socket in which there is a propellant charge and an offensive charge separated by a wad, cartridge wherein said offensive charge is composed projectiles as described above. These cartridges can include indifferently a fat wad or a fluff skirt.

A cartridge according to the invention preferably contains between 50 and 200 projectiles, formed of grains linked in pairs. It is advantageous to use projectiles comprising grains whose diameter is between 2.5 mm and 4 mm, for example 50 projectiles, in the form of 100 grains of 3.5 mm in diameter, linked in pairs. It is recalled that a conventional cartridge of 30 to 35 g or 36 g contains 200 to 300 toxic lead pellets, and a buckshot cartridge comprises on its side less than thirty, commonly 9, 12 or 15.

• se munir d'une machine comprenant i) un four muni d'un réservoir apte à contenir ledit alliage en fusion, ii) un plateau horizontal monté sur un axe de rotation central apte à recevoir et à entraîner en rotation une matrice en polymère, et iii) des moyens pour amener ledit alliage depuis le réservoir jusqu'à un orifice supérieur central de ladite matrice,
• réaliser une matrice en polymère comprenant deux moules séparables, l'un supérieur comportant un orifice central et l'autre inférieur, entre lesquels est ménagé un réseau de canaux ramifiés s'étendant selon une orientation sensiblement radiale depuis ledit orifice supérieur central et se terminant chacun par une cavité sphérique,

• pratiquer dans un des moules des entailles joignant des cavités voisines, prises au moins deux par deux,
• installer un fil métallique traversant lesdites cavités et s'insérant dans lesdites entailles,
• assembler les moules pour former la matrice, la placer sur le plateau, et mettre l'ensemble en rotation,
• couler l'alliage en fusion depuis le réservoir dans la matrice à travers l'orifice central, tout en maintenant ladite matrice en rotation de sorte que l'alliage pénètre dans le réseau de canaux jusqu'aux cavités sphériques par l'effet de la force centrifuge,
• séparer les moules et récupérer des grappes de grains sensiblement sphériques reliés entre eux par un fil.

Il ne reste alors plus qu'à fractionner les grappes de grains liés, en projectiles d'au moins deux grains, à moins qu'on ait prévu dès le départ d'insérer dans les entailles des segments de fil reliant uniquement le nombre de grains désiré.Another object of the present invention is a method of manufacturing projectiles intended to constitute the offensive charge of a firing cartridge, said projectiles being formed of at least two substantially spherical grains connected to each other by a wire of fixed predetermined length. said grains being an alloy comprising tin and antimony. The method essentially comprises the steps of:

• provide a machine comprising i) a furnace provided with a reservoir adapted to contain said molten alloy, ii) a horizontal plate mounted on a central axis of rotation adapted to receive and rotate a polymer matrix, and iii) means for bringing said alloy from the reservoir to a central upper orifice of said matrix,
• producing a polymer matrix comprising two separable molds, one upper having a central orifice and the other lower, between which is formed a network of branched channels extending in a substantially radial orientation from said central upper orifice and each terminating in a spherical cavity,

• practice in one of the molds notches joining neighboring cavities, taken at least two by two,
• installing a wire passing through said cavities and inserted into said notches,
• assemble the molds to form the matrix, place it on the plate, and put the assembly in rotation,
• casting the molten alloy from the reservoir into the die through the central orifice, while maintaining said die in rotation so that the alloy enters the channel network to the spherical cavities by the effect of the force centrifugal,
• separate the molds and recover clusters of substantially spherical grains interconnected by a wire.

It then remains only to split the bunches of bound grains into projectiles of at least two grains, unless it was planned from the outset to insert in the notches segments of wire connecting only the number of grains longed for.

The furnace may be of known type, such as those which have already been used to manufacture insulated lead balls (for example fishing lead), but without using the matrix according to the invention. The casting step with centrifugation lasts a few tens of seconds, for example 20 seconds.

According to the manufacturing method according to the invention, preferably the spherical cavities that are housed in the matrix have a diameter of less than 4 mm.

Also preferably, in the manufacturing method according to the invention, the neighboring cavities between which are made notches, are formed at a distance of between 0.5 mm and 10 mm from each other.

According to an embodiment characteristic of the manufacturing method that is the subject of the invention, the bonding wire is made of metal or metal alloy having a melting temperature greater than that of the alloy of tin and antimony, the latter being 290 ° C (against 450 ° C for lead). Brass melts around 800 ° C. As a result, the brass wire will be embedded and frozen in the tin-antimony alloy during molding to form a predetermined fixed distance grain assembly.

• La fig.1 est une vue en coupe d'une cartouche à bourre grasse selon l'invention.
• La fig. 2 est une vue en coupe d'une cartouche avec bourre à jupe selon l'invention.
• La fig. 3 est une représentation schématique d'une machine pour la réalisation du procédé de fabrication des projectiles, selon l'invention.

The present invention will be better understood, and details will arise, thanks to the description that will be made of one of its variants, in connection with the accompanying figures, in which:

• The fig.1 is a sectional view of a fat-filled cartridge according to the invention.
• The Fig. 2 is a sectional view of a skirt-filled cartridge according to the invention.
• The Fig. 3 is a schematic representation of a machine for carrying out the method of manufacturing the projectiles, according to the invention.

On the fig.1 , there is shown a cartridge for firing with a firearm, comprising the sleeve 1 whose base 21 is here at the bottom. In the sleeve 1, there is a propellant charge 2 and an attacking charge 3, which are separated by a fat wad 4 and a shutter 44. The propellant charge 2, in the lower part of the cartridge (partially obscured by the cap), is classically powder.

Another cartridge according to the invention, represented on the Fig. 2 , is a cartridge with wadding 4 skirt. The skirt forms a bucket 41 whose base is curved and ends with a damping element 42.

These two structures are of known type. They contain the offensive charge 3, i.e., multiple projectiles (as opposed to a bullet that is a single projectile). Each projectile 10 comprises at least two grains 5 connected by a wire 6.

In a first example, the grains 5 are beads 3.5 mm in diameter, consisting of an alloy of tin (94.5%), antimony (5%) and copper (0.5%) . The connecting wire 6 that unites them is brass (lead-free quality). It maintains the grains 6 two by two, separated by a fixed distance of 7.5 mm, which form the projectiles 10. An offensive charge may consist of 50 of these projectiles 10.

In a second example, the grains 5 are beads 2.5 mm in diameter, consisting of an alloy of tin (95%) and antimony (5%). The connecting wire 6 made of brass (unleaded) grits 6 three by three, separated by a fixed distance of 6 mm. One can realize an offensive charge comprising a hundred of these projectiles 10, or 300 grains.

The projectiles can be manufactured as follows, with reference to the Fig. 3 . We use a machine comprising an oven 100 provided with a tank 110 adapted to contain the chosen alloy. The apparatus also comprises a horizontal plate (not shown) mounted on a central axis of rotation adapted to receive and rotate a polymer matrix. The matrix is in the form of two separable molds, one upper (not shown) and the other lower 11. A network of branched channels 13 is formed between the molds. The upper mold is provided with a central upper orifice which is placed in line with a nozzle fed by means designed to bring the molten alloy from the tank 110, and to deliver a quantity of alloy in the upper central orifice of the matrix.

The branched channels 13 extend in a radial orientation from the center 12 of the molds and each terminating in a spherical cavity 14 with a predefined diameter of less than 4 mm. Notches 15 joining cavities 13 adjacent are practiced in one of the molds. The adjacent cavities 14 between which are cut notches 15 are placed at the desired distance from each other, between 0.5 mm and 10 mm.

Then proceed as follows. The tank 110 of the furnace 100 is filled with the compounds forming the desired alloy and is heated to reach the melting temperature of the alloy (ie 290 ° C for a 90% -5% tin-antimony alloy). The lower mold 11 is placed on the tray of the apparatus. Brass wires 6 are installed so that they pass through several cavities 14, inserting them into the slots 15 to hold them in place. The die is closed by the upper mold and the tray is rotated. A quantity of alloy is poured through the central orifice of the matrix. We continue the rotation about twenty seconds. It is allowed to cool for a few minutes before removing the upper mold and then recovering bundles of grain bound by a wire.

It remains to separate the clusters into projectiles 10 of desired length (number of grains 5) and to place them in the tray of a machine to insert.

Claims (15)

1. Offensive charge intended for the manufacture of a multiple projectiles cartridge for firing with a firearm, in which said projectiles (10) are formed by at least two substantially spherical pellets (5) connected to one another by a metal connecting wire (6) with a fixed predetermined length, characterized in that said pellets are made from an alloy comprising tin and antimony and are fused to the metal connecting wire (6).
2. Offensive charge according to claim 1, characterized in that the alloy of the pellets (5) is at least 99% made up of tin and antimony.
3. Offensive charge according to claim 1 or 2, characterized in that the alloy of the pellets (5) comprises from 90% to 98% tin.
4. Offensive charge according to any one of claims 1 to 3, characterized in that the alloy of the pellets (5) comprises from 2% to 10% antimony.
5. Offensive charge according to one of the preceding claims, characterized in that the alloy of the pellets (5) further comprises no more than 1% of a third metal.
6. Offensive charge according to one of the preceding claims, characterized in that the alloy (5) is made up of 94.5% tin, 5% antimony and 0.5% copper.
7. Offensive charge according to one of the preceding claims, characterized in that the connecting wire (6) is made from a metal or a metal alloy having a melting temperature higher than that of the alloy constituting said pellets.
8. Offensive charge according to one of the preceding claims, characterized in that the connecting wire (6) between two pellets (5) is a brass wire with a length comprised between 0.5 mm and 10 mm.
9. Offensive charge according to one of the preceding claims, characterized in that the projectile (10) comprises two connected pellets (5) with a diameter smaller than or equal to 4 mm.
10. Cartridge for shooting with a firearm, comprising a cartridge case (1) in which a propulsive charge (2) and an offensive charge (3) are found separated by a wad (4), characterized in that said offensive charge is according to any one of claims 1 to 9.
11. Cartridge according to claim 10, characterized in that the offensive charge contains between 50 and 200 projectiles (10), formed by pellets (5) connected in pairs.
12. Process for manufacturing an offensive charge according to one of claims 1 to 9, characterized in that it comprises the following steps:

    - getting a polymer matrix comprising two separable molds, i.e., an upper one including a central orifice, and a lower one (11), between which an array of branched channels (13) is arranged extending along a substantially radial orientation from said central upper orifice and each ending with a spherical cavity (14);

    - installing a metal wire (6) traversing said cavities;

    - pouring the alloy containing tin and antimony into said matrix,

    - separating the molds and recovering the clusters of substantially spherical pellets connected to one another by said metal wire (6).
13. Manufacturing process according to claim 12, characterized in that the metal connecting wire (6) is installed into notches (15) formed between adjacent cavities taken at least in pairs.
14. Manufacturing process according to one of claim 12 or 13, characterized in that the spherical cavities (14) of the matrix have a diameter smaller than or equal to 4 mm.
15. Manufacturing process according to one of claim 12 to 14, characterized in that the cavities are arranged at a distance from one another comprised between 0.5 mm and 10 mm.

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