FR2580065A1 - Firearm barrel made of lightweight composite materials of high mechanical strength - Google Patents

Abstract

The invention relates to devices making it possible to use carbon or aramid fibres, which may or may not be combined with glass fibres, and which are coated with resins forming, with steel and light alloy tubes, a barrel made of laminated composite materials hooped by means of an outer steel envelope. The low weight of the assembly is noteworthy and the strength is constant, whatever the temperatures reached as a result of the firing frequencies.

Description

PATENT
COMPOSITE MATERIAL FIREARMS
LARGE MECHANICAL STRENGTH AND LOW WEIGHT
It is clear that the lighter the barrel of a firearm, the easier it will be to transport that weapon. Thus will be lightened the load of the shooter or that of the aircraft carrying this weapon.

To lighten the barrel, cn can consider using carbon fibers, aramids associated or not with glass fibers and taken in resins which would curl around a metallic tube of thin wall, along which The projectile will move. This helical coiling of fibers with high resistance and low density would have the advantage of making the internal metallic barrel perfectly resistant to centrifugal pressure, sometimes reaching 3,500 bars a fraction of a second at the level of the breech, resulting from the expansion of hot gases during the explosion propelling the projectile outwards. It would however have major drawbacks: on the one hand the heat energy released during repeated explosions, firing in long bursts for example, 2503 would be badly evacuated because of the bad heat conductivity of the coiled fibers, on the other hand , the surface hardness of the fiber being quite low, the barrel would not withstand external shocks well.

The devices according to the invention overcome these drawbacks by allowing the use of synthetic, carbon or aramid and glass fibers taken from resins, by using bridges made of aluminum alloy or of another light and conductive metal. , distributed along the barrel at increasing distances from the breech to the muzzle of the barrel, these bridges being separated by large zones of fibers wound around the internal barrel, the assembly being hooped inside a wall external metal protecting the fiber and ensuring total cohesion of this "sandwich" set of laminated compcsites. This cohesion is ensured at low firing temperatures, despite the different expansion coefficients of the materials used. Indeed, steels, alloys and fibers do not expand in the same proportions, but their cohesion is well maintained thanks to the centripetal forces exerted in permanently by the hooped external metallic envelope putting them under constant tension.

In addition, this mechanical hooping which puts under tension these composite materials, gives them an elasticity which absorbs harmful vibrations.

To clearly understand the invention, there will be briefly described below an example of execution without limitation, with reference to the schematic drawings annexed dans.lesquels Figure 1 shows a section of the barrel in the longitudinal direction. This section shows the different layered layers (sandwich) and the distribution areas by bridges of the various materials used.

Thus in 1, the wall of the internal treated steel tube may be scratched (olivage) to impart to the projectile the rotation which stabilizes it on its trajectory.

In 2, the first metallic and conductive light alloy bridge.

This first pcnt located at the level of the explosion chamber, is of a length greater than the other bridges 3, 4, 5 and 6, because the quantity of heat energy to be evacuated at this level is very significantly greater than that which l 'will be found at the level of the muzzle of the barrel.

Thus, bridges 3, 4, 5 and 6 are increasingly spaced as one moves away from the breech along the barrel.

In 7, 8 and 9 zones of carbon fibers (7), carbon and glass (8), glass (9), these materials being of decreasing resistance since the forces decrease as the gases relax , are wound helically around the inner tube 1.

In 10, the outer tube shrunk around the assembly providing final surface protection, but above all the cohesion of the composite sandwich assembly whatever the firing temperature. Indeed, the centripetal force resulting from the tensioning force during hooping, is exerted constantly whatever the temperature on all the bridges and the internal barrel, these elements being arranged against each other, without be bonded with adhesives, allowing them to expand independently.

Figure 2 shows a section of the barrel at height A in the diametral direction.

In 1 the treated steel tube forming the barrel chamber, in 2 the alloy bridge transmitting the heat energy taken from the internal tube to the external hooped metal tube 10.

Figure 3 shows a section of the barrel at height B in the diametrical direction.

In 1, the treated steel tube forming the barrel chamber, in 8, the bridge in fibers tightly wound in spiral wrapping around the internal tube, in 10, the external hooped metal tube exerting the centripetal forces f on the whole
sandwich ".

Claims (6)

- CLAIMS 1) Set of composite materials consisting of metal alloys and  synthetic fibers, carbon, aramids and glass diosposed around a  internal metal tube, then hooped by an external metal tube allows  so much so to constitute a very light gun cancn. 2) Set of materials according to claim 1 characterized in that  metal bridges in light alloys are placed to dissipate the heat energy  fique released during the expansion of the gases towards the outside of the barrel on  decreasing lengths from the breech, along the barrel. 3) set of materials according to claim 1 characterized in that the fibers  low density will be used in addition to large quantities, depending on whether  the barrel will be intended for shots by bursts generating a fcrt heating  cu, on the other hand, ccup shots by ccup. 4) compcsite assembly according to claim 1, characterized in that the bridges  fibers of ncrmales lengths towards the exit of the barrel consist of  fibers whose mechanical qualities are decreasing, as allowed by  decreasing pressures to support. 5) composite assembly according to claim 1, characterized in that the envelope  external metallic shield protecting the entire barrel is shrunk to  put under constant tension along the barrel the laminated materials scus-  underlying, these expand differently depending on the temperatures of use  from the barrel. 6) composite assembly according to any one of the preceding claims  characterized in that the external metallic hooped tube which energizes  all the laminated materials, allows the absorption of harmful vibrations.