EP3682185B1 - Machine gun - Google Patents

Description

Object of the invention

The present invention relates to a machine gun, to the supply system and to the frame of such a machine gun, as for example described in US2545068A .

State of the art

The ergonomics of a weapon is a rather specific notion in the sense that it brings together a certain number of criteria ranging from the mass and size of a weapon to its grip in the shooting and handling conditions. It is generally accepted that a weapon with better ergonomics is a weapon that allows its user to better fulfill his role within his unit. Improving the weapon's ergonomics can translate into different ways in the field. It can lead to an increase in the mobility of the user, an improvement in the availability of the weapon on the ground, an facilitation of the use of the weapon...

A machine gun is understood to mean a firearm capable of firing a strip of ammunition, as opposed to firearms being fed from a magazine (rifle or pistol). The ammunition belt consists of a series of cartridges linked together by links, said links detaching from each other when the cartridges are extracted.

The carcass of a machine gun is the central part of the weapon, which acts both as the main structural element, but also as a reference base for the positioning of all the added or assembled parts which carry out the operating cycle of tear.

In the majority of machine guns the functions related to the tape feed are present in the upper part of the weapon. The ammunition strip being placed manually on a feed passage before being held by various elements present in the feed cover. The main advantage of this configuration is that it facilitates handling of rearmament and resolution of firing incidents due to the horizontal positioning of the supply corridor as well as due to the good accessibility, both visual and touch, of the elements carrying out power functions.

A disadvantage of this architecture is that, since the sighting systems are placed above the barrel, it is necessary to integrate them partially (mechanical sighting devices with front sight eyelet) or completely (modular sighting devices mounted via a standard Picatinny rail) on the weapon's feed cover. This results in some inaccuracy in the alignment of the aiming point and the point of impact of the projectiles due to the uncertainty of the repositioning of the feed cover each time it is opened and closed.

Another drawback is the impossibility of using certain optical components (high-magnification long telescope, light intensifier, night sight, etc.) due to the additional bulk of the main sighting optics when the cover of supply is in the open position. In fact, for top-loading machine guns with a long cover, the sights are mounted directly on the cover, which means that when it is opened, the sight is also tilted, which means that shift light intensifier type devices forward. The latter no longer being mounted directly in front of the telescope but further forward with a day between the two optics conducive to pollution both optical (reflections from a light source) and physical (pollution by sand, mud ...).

Following the firing of a large number of ammunition in a limited time, the barrel heats up strongly. Another disadvantage of mounting optics on long covers is that when the cover is held open, the optics face the barrel. In this case the heat of the barrel is transmitted to the optics which can significantly degrade it, the latter not being designed to withstand such high temperatures. To avoid this, it is necessary to place a heat deflector (heatshield) between the barrel and the optics which weighs down the machine gun.

On some machine guns (like the IMI Negev machine gun) the choice was made to limit the length of the feed cover to the maximum. This makes it possible to reduce the drawbacks mentioned above by mounting the optics on the rear of the frame, but this strongly constrains the length of the optics compatible with the weapon. Indeed, in this case, it is necessary that the optics does not pass above the supply cover to allow the opening of the latter. This limitation also applies to the alignment of several optical components (light intensifier in front of a conventional sighting component, etc.), the front component must, in this case, either be mounted on the cover (this which leads to the drawbacks mentioned above concerning the limitations of the sights mounted directly on the feed cover), or be mounted in front of the feed cover which considerably separates it from the two optical devices.

To work around these problems, some weapons have proposed alternative architectures by positioning the power supply functions either in the lower part of the weapon (like the HK 21 and HK 23, XM 248 machine guns), or on the side of the weapon with a vertical feed corridor (United States 7.92mm light machine gun t44, side-feed M60). These two alternatives present major drawbacks with regard to the operations of changing bands as well as the resolution of firing incidents. When the feed is from the bottom, the accessibility of the strip advance elements as well as the chamber is very limited, which complicates the operations of checking the empty chamber, as well as the resolution of problems related to the feed. or extraction.

When the feed is lateral with a vertical feed passage, the problems encountered relate mainly to the installation of a new strip of ammunition. Indeed it will often tend to move or even fall before the operator has had time to close the cover of the weapon. These various disadvantages are very penalizing because the operations of rearmaments or resolution of the incidents of shootings are likely to arrive at the worst moment (in full engagement, under an enemy fire) and result in a loss of firepower over a longer time. or shorter.

Usually, the carcass of a machine gun is made by assembling intermediate components. The objective is to be able to carry out the finishing machining of the various parts with precision before assembling them. The various components have an “open” shape which allows access to cutting tools (for milling or turning). For machine guns this opening is generally made in the upper part of the carcass because it will be covered by the feed cover which is removable to allow the installation of a new band.

As part of a machine gun, this type of assembly requires the use of steel. Indeed, to maintain sufficient stiffness and avoid weakened areas at assembly points, a material with a Young's modulus and a sufficient elastic limit are often required. This is amplified by the fact that a machine gun must maintain a higher volume of fire than other weapons which implies an increase in the temperature of the weapon and therefore a degradation in the performance of the materials. For both historical and economic reasons, the preferred material for this application has always been steel. The main consequence of the choice of steel for the carcass of the machine gun is a noticeable weighting of the weapon. As a result, machine guns are generally significantly heavier than other long guns used by infantry units, which significantly penalizes the mobility of the entire unit.

Moreover, for a machine gun, the ejection of the links is generally carried out by the dynamics of the band in motion: when the band is pushed by its advance mechanism, the link released from its cartridge is directed towards its ejection window. out of the carcass. In particular, once the last cartridge has been fed, 2 links remain to be ejected. No mechanism is provided for this particular case of the last cartridge.

The main risk of this mode of operation is to allow a link to enter inside the carcass through the opening of the feed passage which allows the passage of the bolt and the cartridge. If a link enters inside the carcass it will cause a shooting incident by blocking the movement and the mechanism of the parts included inside the weapon. This risk is increased if the machine gun's feed passage is tilted from the horizontal: gravity can then direct the link towards the opening of the feed passage.

A second problem is that the last link generally remains on the feed corridor, the soldier must usually "clean" this before positioning a new strip, and there is therefore an associated loss of time.

Finally, in the machine guns of the prior art, nothing perfectly maintains (according to 6 degrees of freedom) the band on the feed passage when the cover is open. The reloading of a machine gun is frequently done with one hand on the handle, the second free hand having to open the lid then position the tape on it, before letting go to close the lid. This loading operation is often carried out under stress since in a vulnerable position without ammunition ready to fire. If during this operation the machine gun is set in motion, its feed passage tilted, there is a risk that the belt is not positioned correctly once the lid is closed. The loading operation will then be followed by a firing incident (no firing of a shot).

• Le couvercle mobile disposé sur le haut de l'arme empêche le positionnement fiable d'accessoires fixes tel qu'une lunette de visée ;
• En fin de bande, un ou des maillons restent généralement dans le couloir, et, le tireur doit généralement évacuer ces maillons avant de pouvoir recharger ;
• La mauvaise évacuation d'un maillon peut entrainer un incident de tir en bloquant le mécanisme de rechargement ;
• Le positionnement de la bande, et en particulier le positionnement de la première cartouche est peu précis et peut aussi entrainer des incidents de tir ;
• La bande n'étant pas maintenue, l'utilisateur doit la maintenir jusqu'à la fermeture du couvercle, ce qui oblige à l'utilisation des deux mains.

In summary, conventional machine guns have the following main drawbacks:

• The movable cover arranged on the top of the weapon prevents the reliable positioning of fixed accessories such as a sight;
• At the end of the band, one or more links generally remain in the corridor, and the shooter must generally evacuate these links before being able to reload;
• The poor evacuation of a link can lead to a firing incident by blocking the reloading mechanism;
• The positioning of the band, and in particular the positioning of the first cartridge is imprecise and can also cause firing incidents;
• Since the band is not maintained, the user must maintain it until the cover is closed, which requires the use of both hands.

Summary of the invention

The invention relates to a machine gun according to claim 1. Preferred embodiments are defined in dependent claims 2 to 5.

Brief description of figures

• The figure 1 shows a side view of a machine gun according to the invention.
• The figure 2 shows a perspective view of an example of a feed corridor according to the invention, lid open, an ammunition strip in place.
• The picture 3 shows a perspective view of an example of a feed passage according to the invention, lid open, without ammunition strip.
• The figure 4 shows a sectional view of a device according to the invention, the cover being partially closed.
• The figure 5 shows a sectional view of the device of the figure 4 , the lid closed.
• them figures 6 to 8 represent sectional views of the device of the figure 4 during a firing and rearming cycle of a machine gun of the invention.
• them figures 9 to 12 represent sectional views of the device of the figure 4 during the firing cycle of the last cartridge of an ammunition strip of a machine gun of the invention.
• The figure 13 shows a standing view of a feed channel comprising tape holding means according to the invention.
• The figure 14 represents a claw for advancing the band and ejecting the last link according to an example of the invention.
• The figure 15 represents an example of a machine gun carcass according to the invention.
• The figure 16 shows an exploded view of a feed passage according to the invention.
• The figure 17 shows an exploded view of a feed alley cover according to the invention
• The figure 18 shows a perspective view of another example of a feed channel comprising means for repositioning the strip.
• The figure 19 shows an exploded view of the corridor of the figure 18
• The figure 20 and 21 represent sectional views of the device comprising the corridor of the figure 18 and 19 , showing the movement induced by closing the lid.

Detailed description of the invention

The present description essentially describes an example of a weapon implementing the present invention.

In the present description, we will call “last ammunition” that which is at the end of the strip, either in position or ready to be fed. The links will of course be named in the same way.

The term longitudinal, when referring to a feed corridor, or the movement of an ammunition belt refers to the direction of travel feed of the strip, the barrel therefore being in the transverse direction with respect to the longitudinal direction of feed of the weapon.

The figure 1 represents an example of a machine gun according to the invention. This machine gun has a side feed allowing the use of a Picatinny 21 type rail, continuous and fixed on the top of the carcass body 22. Above, we mean the upper part when the weapon is used according to a conventional position . Of course, other types of accessory attachment interfaces could be used.

The figure 2 shows a perspective view of the feed corridor with an ammunition strip 5 positioned, cover 2 open. This cover comprises closing means 19 cooperating with corresponding means on the carcass 22.

The picture 3 , represents the same corridor, without the strip of ammunition 5, which makes it possible to distinguish the pawls 15 and 14, pushing respectively on the front part of the penultimate ammunition, and on the central part 10 of the penultimate link. These pawls 14, 15 project from the sliding surface 3 of the ammunition strip 5. As we will see later, the central position of the pawl 14 makes it possible to eject the last link.

It is also observed in these figures that the sliding surface 3 of the feed channel, and the corresponding surface of the cover 2 are inclined at 45°, while the common axis 4 of these two sets is vertical. This secant arrangement of the axis of rotation of the cover with respect to the sliding plane of the ammunition allows the cover to have a component of movement, when closing, parallel to the sliding movement of the ammunition 18.

This horizontal component allows a non-return pawl 12 to push on the penultimate ammunition (or rather here on the central part of the penultimate link. This positioning movement is better illustrated in the sections of figure 4 and 5 .

To the figure 4 , the cover is not yet closed, and the strip rests on the strip advance pawls 16, 15. These pawls 15,16, free to rotate around their axis, do not allow precise positioning of the strip 5 . In particular, we see at the figure 4 too low positioning of the last ammunition (ie the ammunition is not "in position" positioned in the middle of the opening of the feed corridor). Finally, the position of the advance pawls depends on the position of the bolt 17 and of the moving parts, which is not unequivocal during the placement of the band, in particular in the case of a weapon operating with an open bolt: the bolt 17 can be in the forward position, chamber empty and locked, or the lock 17 is in the rear position, chamber empty. Depending on the case (and depending on the drive mechanisms of the band) the pawls 14, 15, 16 of advancement will be at different positions.

We observe at the figure 5 , after closing the cover, that the pressure of the non-return pawl 12 on the penultimate ammunition has made it possible to reposition the band 5 correctly.

It should be noted that the repositioning of the band can be obtained in other ways, the main thing being that the closing movement of the lid can induce a readjustment movement of the band parallel to the sliding of the latter.

Such an alternative example is shown for a horizontal supply corridor 100 at the figures 18 to 21 . In this example, the band 5 slides on a horizontal surface 102 and is correctly positioned by non-return pawls 101 actuated by closing the cover 107. To this end, the non-return pawls 101 are fixed on a slider 103 comprising a inclined surface 105 cooperating with a corresponding inclined surface 106 on the cover 107.

In all cases, during the movement of the tape induced by the tape advance mechanism, the non-return pawls 101, 12 can be erased to allow the successive munitions 18 to pass in the normal feed direction.

The lateral positioning of the power supply figures 2 to 12 , as well as the opening direction of the lid 2 and of the feed passage along a vertical axis also makes it possible to release the upper face of the carcass, and allows the fixing of a fixed rail 21 on a carcass body 22 essentially tubular .

The 45° inclination of the sliding plane 3 of the feed passage has the advantage already mentioned of allowing, in combination with the axis of rotation 4 of the vertical cover, the adjustment of the ammunition in position. Moreover, this inclination facilitates the positioning of the band, by hooking the band on the advance pawls 14, 15, 16 either by keeping the weapon vertical (which is not possible for weapons with a vertical feed passage), or by tilting the weapon by only 45° to place the horizontal passage . It is understood that other angles of inclination are possible, provided that the lateral space is sufficiently limited, and that the horizontal component of the sliding plane 3 is sufficient so that the strip of stably on the advance pawls 14, 15 16 without tilting the weapon. Reasonable angles of inclination are between 20 and 70°, preferably between 30 and 60°.

The figures 5 to 8 illustrate the operation of the power system of the example of the invention. In this example, the machine gun operates according to a so-called “open bolt” cycle, ie a device in which, when not firing, the bolt 17 and the moving parts are in the rear position, chamber open and empty. The complete cycle of a shot is then as follows: The release of the trigger releases the moving parts and the lock 17, which introduces in passing, via its ergo 20, an ammunition 18 into the chamber. At the end of the forward movement, the bolt is locked to the bolt ring, behind the barrel chamber. This forward movement is induced by a recoil spring compressed during the rearward movement of the moving parts. The ammunition is then struck, and gas recovery in the last section of the barrel allows the moving parts to be returned to the rear by compressing the recuperator spring.

After the firing of the last ammunition, the trigger being generally kept pressed, the moving parts perform a final forward movement, and the weapon finds itself with the breech closed, the chamber empty. Depending on whether the user reloads the mechanism before or after placing the ammunition strip, the moving parts are therefore in a forward or reverse position.

The figure 5 shows the weapon in the waiting position, moving parts towards the rear, ammunition in position, the lug 20 of the bolt 17 placed behind the ammunition in position. The band advance pawls 14, 15, 16 are in the low position behind the penultimate ammunition, the band rests on the non-return pawl 12 and the holding valves 11 press on the links and hold the ammunition in position in the middle of the opening of the feed corridor, ready to be fed by the lock 17. A ejection claw 13 pushes on the front side parts 9 of the penultimate link.

When the shot is triggered, the last ammunition is driven into the chamber by the lug 20 of the bolt 17. During this movement, as soon as the ammunition is completely unlinked, the advance pawls 14, 15, 16 begin to advance.

Then, as shown in figure 6 , during the forward movement of the moving parts, the advancing pawls 14, 15, 16 push the band 5 towards the new position a station. To the figure 7 , the last link is ejected by the movement of the belt, pushed by the link and the next ammunition. The ejection claw 13 has pushed on the side parts 9 of the penultimate link, but, this penultimate link being linked to the penultimate ammunition, it is not ejected. As we will see later in fact, this ejection claw only comes into action when the last two links of a band are ejected. The figure 8 shows the return movement of the advancing pawls 14, 15, 16 during the backward movement of the moving parts. During this movement, the strip 5 is retained in position by the non-return pawl 12. At the end of the cycle, the situation of the figure 5 .

The figures 9 to 12 illustrate the ejection of the last two links, during the firing of the last ammunition. To the figure 9 , at the start of the cycle, the last ammunition is in position and the central part 10 of the last link rests on the non-return pawl 12. Note that at this stage, the lateral advancement pawls 15 and 16 no longer rest on ammunition and can no longer push on the rest of the gang. Only the central pawl 14 is still facing the central part 10 of the penultimate link, which, at the start of the cycle, rests on the non-return pawl 12. At the figure 10 , the ammunition is loaded into the chamber.

Then, the central pawl 14 pushes the penultimate link to the position of the figure 11 . In this figure, we have shown an enlargement insert where only the penultimate link, the link ejector 13 and the sliding surfaces 3 have been shown. We see on this insert the force F applied by the ejector 13 on the front side parts 9 of the penultimate link. This force breaks down into a force normal to the surface of the link F _n and a tangential force Ft. Beyond a certain position, the tangential force F _t exceeds the static friction threshold, while the normal force F _n is practically parallel to the sliding plane 3. At this moment, the link is suddenly ejected, and also pushes the link in front of him.

Finally, when the last link is ejected, the claw 13 no longer rests on an ammunition, and, therefore, occupies an extreme position that it never occupies during a cycle in the presence of a strip of ammunition. This movement towards an extreme position can be used to move a band indicator giving an indication of the absence of a band.

We see at the figure 2 retaining rails 6, 7 lining the upper edge of the side faces 8, 23 of the feed passage. The figure 13 shows a section of the supply corridor, with ammunition in position. In this figure, there is a front slide 6 and a rear slide 7 retaining the ammunition 18 in the feed passage via surfaces 25, 29 facing the sliding surface 3 of the band.

These slides 6.7 are held in the holding position by springs 24. These springs make it possible to introduce the strip by separating the two slides. This spacing is advantageously obtained thanks to inclined surfaces 27, 28 on the upper face of the slides, the spacing then being obtained by simply pushing the strip against the slides. Note that it would be enough for only one slide to be mobile to introduce the strip. In the latter case, however, the manipulation would be less flexible (obligation to introduce according to a predefined direction).

Alternatively, the retractable slides 6, 7 could be replaced by holding surfaces facing the sliding surface 3 directly fixed (see, forming part) to the side faces 23, 8 of the feed passage, or these surfaces, either the walls of the feed passage being sufficiently flexible to allow the placement "in force" of the strip.

The advantage of these holding means is to allow placement of the strip, or to open the cover 2 of the feed passage independently of the orientation of the weapon without the strip falling from the passage.

We notice at the figure 13 the presence of a chamfer 26 at the edge of the rear slide 7. This chamfer is only present opposite the last ammunition and makes it possible to remove the strip by a twisting movement, or a lifting movement of the rear part of the ammunition corresponding to the entry of the strip into the feed passage, which pushes back, thanks to the chamfer, the rear slide 7.

The figures 14 to 17 show different elements separated in perspective, so as to clarify the parts possibly hidden in the previous figures.

The figure 14 shows a tape drive claw. This claw has three pawls 14, 15, 16. The two lateral pawls bear directly on the penultimate ammunition, respectively in front of and behind the front lateral parts 9 of the penultimate link. The pawl 14 meanwhile pushes on the central part 10 of the penultimate link.

These three pawls 14, 15, 16 can be integral, or, preferably, the central pawl 14 is elastically linked to the other two pawls, for example via a torsion spring. Indeed there is a space between the ammunition which allows a greater amplitude of movement for the side pawls 15, 16 than for the central pawl, blocked by the surface linking the successive links. Therefore, the support offered by the central pawl 14 provides a less reliable support, and potentially prevents the side pawls from taking an optimal position. Separating the central pawl 14 then allows an optimal range of motion for the side pawls 15, 16.

Note that, when the last link is ejected, the central pawl 14 is no longer blocked by the surface linking the successive links, and it can then take on a more reliable bearing surface. At this time, too, as mentioned above, the lateral pawls 15, 16 no longer rest on an ammunition, and therefore no longer participate in the movement of the band.

The figure 15 shows a tubular carcass body 22. This closed geometry makes it possible to obtain better rigidity, and in particular better resistance to torsion than open profiles. As seen in this figure, the lateral positioning of the feed corridor allows the attachment of a fixed Picatinny rail 21. In addition, the positioning of the carcass side tape feed mechanism rather than in the cover allows a side opening of short length, which further improves the mechanical properties of the assembly.

The figure 16 shows an exploded view of the feed alley. The two springs 24 holding the slides 6, 7 can be seen there.

Claims (5)

1. A machine gun (1) comprising a feed channel comprising a main slip surface (3) for a belt of ammunition items (5), lateral surfaces (8, 23) guiding the belt (5) of ammunition items (18) in use, and holding surfaces (25, 29) for the belt (5) positioned at the upper edge of the lateral surfaces (8, 23), said holding surfaces (25, 29) facing the slip surface (3) and said holding surfaces (29, 25) being open so as to allow the introduction of the belt (5) of ammunition items (18), the holding surfaces being narrow and elastic, allowing a "forceful" introduction of the belt (5) or the holding surfaces (25, 29) of the belt (5) belonging to runners (6, 7) arranged along the upper edges of the lateral surfaces (8, 23) of the feed channel, these runners (6, 7) being held in the holding position by springs (24) and having an inclined upper surface (27, 28) allowing placement of the belt (5) of ammunition items (18) by simple pressing thereof against the inclined surface (27, 28) of the runner (6, 7).
2. The machine gun (1) according to claim 1, wherein the retractable runner(s) (6, 7) have a chamfer (26) at the inlet of the feed channel allowing a belt (5) of ammunition items (18) to be removed by twisting the belt (5).
3. The machine gun (1) according to one of the preceding claims, comprising a cover (2) for the feed channel, the closing movement of which causes an adjustment of the longitudinal position of the belt (5) of ammunition items (18) in the feed channel.
4. The machine gun (1) according to one of the preceding claims, comprising a mechanism for ejecting the last two links of said belt (5).
5. The machine gun (1) according to one of the preceding claims, comprising a frame body (22) having an essentially tubular geometry.

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