1. Field of Invention
The technical scope of the invention is that of muzzle brakes for weapons.
2. Description of the Related Art
Muzzle brakes are well known to somebody skilled in the art. After firing, they enable part of the propellant gases of a piece of ammunition to be directed towards gas reception vanes integral with the gun barrel. The gases thereby exert a force on the vanes that oppose the recoil stress.
Patent FR2718839 describes such a known muzzle brake.
Generally speaking, a muzzle brake is sought to be designed that is as efficient as possible in its braking capacity but whose mass is as small as possible so as to reduce the mechanical torques on the gun trunnions.
These two requirements are, a priori, contradictory since a simple means of improving efficiency is to increases the reception surfaces for the gases thereby leading to an increase in the dimension and thus the mass of the muzzle brake.
The aim of the invention is to propose an extremely efficient muzzle brake with a mass that is as low as possible.
A further aim of the invention is to propose means enabling a muzzle brake to be simply and reliably joined to a gun barrel.
Thus, the invention relates to a muzzle brake for a gun comprising at least one substantially cylindrical body intended to be positioned in the extension of a gun barrel, such body incorporating at least two stages of gas reception vanes, such body perforated by vents directing the propellant gases towards the vanes, brake wherein it incorporates at least one means to deflect the gas flow, such means positioned between the vents of the second stage of vanes and a front profile of the vanes of the first stage.
According to one characteristic of the invention, the deflector means are constituted by a flange extending angularly over all the width of the front profile of the vanes of the first stage.
The vanes of the second stage may be advantageously shaped as relatively thin dividers having at least one reinforcing rib oriented substantially radially with respect to the brake axis.
Each vane of the second stage may also be connected to a vane of the first stage by relatively thin dividers delimiting a chamber that communicates with the exterior by an opening having a substantially rectangular section, such dividers having at least one second reinforcing rib oriented substantially in parallel to the muzzle axis.
The dividers may have a second reinforcing rib positioned in the vicinity of the mouth of the opening delimited by the dividers, such rib extending longitudinally on either side of the first radial rib and up to the vane of the first stage.
The dividers delimiting each chamber of the second stage may incorporate substantially plane portions parallel to the brake axis and which extend up to the body by plane, substantially radial portions.
The width of the chamber openings in the second stage may be between 100% and 200% of the gun calibre.
The radial portions delimiting each chamber may form an angle between 100° and 150°.
The brake will preferably be made of cast steel or cast titanium, materials having in any case a limit of elasticity greater than or equal to 1000 MPa.
According to another characteristic of the invention, the brake vents may be radial perforations having the profile of extensions slots extending longitudinally over the full length of the chamber.
The muzzle brake will advantageously incorporate two or three vents in each chamber.
According to another characteristic of the invention, the brake may incorporate an internal bore having two different diameters separated by a counter-sink forming an axial limit stop for the gun barrel, a first diameter being equal to the external diameter of a front end of the gun barrel and a second diameter being equal to the calibre of the gun barrel.
According to another characteristic of the invention, the muzzle brake may incorporate an opening intended to receive a cleat to ensure its joining with the gun barrel, such cleat being fastened by flanges to the brake body and incorporating two concurrent plane surfaces intended to cooperate with matching surfaces on the gun barrel so as to prevent the relative rotation of the brake/barrel.
The cleat may advantageously incorporate means to fasten a barrel reflector.
The invention will become more apparent from the following description made of one embodiment, such description being made with reference to the appended drawings, in which:
With reference to
The muzzle brake 1 comprises a substantially cylindrical body 5 fastened in the extension of the barrel 2.
The body 5 has two stages 6a, 6b of gas reception vanes (refer also to
Classically, the body 5 is perforated with vents 7 enabling the propellant gases to be directed towards vanes 6a and 6b. The vents directing the gases towards the first stage of vanes 6a are designated as 7a in the Figures. Those which direct the gases to the second stage of vanes 6b are designated 7b in the Figures.
Vents 7, here, are radial perforations and are thus perpendicular to the longitudinal axis 8 of the brake 1. They have the profile of elongated slots extending longitudinally for a length that enables their impact on the ammunition to be limited.
In accordance with one characteristic of the invention, the vanes 6b of the second stage are formed into relatively thin dividers (of a thickness less than 10 mm) provided with reinforcing ribs 9.
Thus, each vane 6b of the second stage is connected to a vane 6a of the first stage by relatively thin dividers 10 (of a thickness less than 10 mm) which delimit a chamber 11 communicating with the exterior by an opening 12 with a substantially rectangular section (refer in particular to
These dividers 10 extend beyond the vanes 6a of the first stage by panels 10a connected to the body 5 and thus delimiting two other chambers surrounding the vents 7a in the first stage.
As is more particularly visible in
Furthermore, the dividers 10 also incorporate a second reinforcing rib 9b positioned in the vicinity of the mouth of the opening 12 delimited by the dividers 10 (see also
This rib 9b extends longitudinally on either side of the radial rib 9a and up to the vane 6a of the first stage. Each longitudinal rib 9a is thus oriented substantially in parallel to the brake axis 8.
This design of the brake stages in the form of thin ribbed dividers enables the muzzle brake to be made considerably lighter whilst retaining its mechanical strength.
The material implemented to make the brake will be a cast steel having high mechanical strength (limit of elasticity (Rp0.2) greater or equal to 1000 MPa. The brake may also be made of cast titanium that has a similar limit of elasticity.
The first reinforcing rib 9a (or front rib) limits the deformation of the vent 6b under the effect of the gas pressure.
The second reinforcing rib 9b (or peripheral rib) reinforces the dividers 10 delimiting the chambers 11 preventing them from opening under the effect of the gas pressure.
Moreover, and as may be more particularly seen in
The plane portions 10c extend up to the body 5 of the brake 1 by plane portions 10d that are oriented substantially radially with respect to the body 5 of the brake 1.
The plane portions 10d define plane radial planes 15 (or opening planes for the chambers 11 of the brake 1) which together form an angle □ of around 120° (this angle may be of 100° to 150°).
Three vents 7b are positioned in each chamber 11. The vents are evenly spaced angularly in an opening sector of 120°.
The width L of the chamber 12 openings in the second stage is thus between 100% and 200% of the calibre of the weapon.
Such an arrangement, for a given calibre, facilitates maximal withdrawal of gas and thus maximal braking efficiency. The gases are then evacuated after being channeled by the plane portions 10c. The gases are thus ejected in a horizontal direction parallel to plane AA.
According to an important characteristic of the invention, the brake incorporates at least one means 13 to deflect the gas flow, such means being positioned between the vents 7b of the second stage of vanes and the front profile 14 of the vanes of the first stage (see
The deflector means are constituted by a flange 13 extending angularly over the full length of the front profile 14 of the vanes 6a of the first stage, thus over the full angular sector a delimited by the radial planes 15.
The flange 13 is succeeded by a groove 26. This results in the aerodynamic flow being deviated upon exiting the vents 7b. This further results in a depression in the groove 26 and along the front profile 14. The pressure exerted along the front profile 14 is thereby limited, pressure which would otherwise exert an effect opposing the braking. The global performance of the brake is thus improved. Moreover, the deflector 13 enables the gas ejection rate to be increased further improving the performance of the muzzle brake.
With respect to a classical brake incorporating two stages of vanes, the brake according to the invention has a mass reduced by 10 to 20% (this thanks to the partitioned structure). Moreover, its performance is improved by 5 to 10% thanks to the deflector and to the chamber profile.
Reference to
The rear part 16a has a diameter equal to the external diameter of the front end of the gun barrel 2. The front part 16b has a diameter equal to the calibre of the gun barrel. Thus, the counter-sink 17 is equal to the thickness of the gun barrel 2. Thus, after firing, a projectile is guided inside the muzzle brake as it is inside the gun barrel.
The rear part 16a of the bore has artillery threading 18 intended to allow the brake 1 to be screwed onto the gun barrel 2 which has matching threading.
The gun barrel 2 naturally incorporates a smooth forward seat (not shown) extending its threaded part, such seat fitting into the rear part 16a of the bore. This forward seat incorporates oblong drill holes (not shown) positioned angularly such that they lie opposite the vents 7a of the first stage of the muzzle brake.
Such a structure of the perforated gun barrel whose drill holes cooperate with the vents of a muzzle brake is well known, namely by patent FR2718839. It is thus unnecessary to describe this structure of the barrel 2 in any further detail.
In accordance with another characteristic of the invention, the muzzle brake 1 incorporates an opening 19 intended to receive the cleat 3 ensuring it is joined with the gun barrel 2.
This opening is globally rectangular in shape. It is housed between the upper panels 10a delimiting the chambers surrounding the vents 7a of the first stage. Two extra thicknesses 20a and 20b of the brake body 5 are positioned on either side of the opening 19 (
These extra thicknesses are threaded 22 (see
As may be more particularly seen in
The end surfaces 24a and 24b are concurrent. Thus, when they are applied against the barrel 2 they prevent any relative rotation of the brake 1 with respect to the barrel 2.
The brake is thus very simply joined to the gun barrel. Indeed, its axial immobilization is obtained by the abutment of the end of the barrel 2 against the counter-sink 17. Its immobilization in rotation is then ensured by simply fastening the cleat 3 in the opening 19.
Advantageously, the cleat 3 will incorporate a prismatic extension 25 on its upper part which will enable a barrel reflector to be affixed. This may be done simply by means of the threading 26.
Such an arrangement simplifies the fastening of such reflectors. Indeed, in a known manner these reflectors are reference means enabling the fire control to know the actual geometric position of the end of a gun barrel.
For firing to be accurate, it is thus essential for the reflector to be exactly positioned with respect to the barrel. Here, thanks to the invention, the position of the extension 25 with respect to the barrel is precisely controlled since this extension is integral with the tongues 24a, 24b which press directly on the barrel 2.
Thus, the cleat 3 proposed by the invention enables the muzzle brake to be joined whilst providing a spatial reference of the end of the gun barrel.
Such a cleat may naturally be implemented with another type of muzzle brake.
Number | Date | Country | Kind |
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04.05440 | May 2004 | FR | national |