Abstract:
A weapon barrel muzzle brake ( 5 ) with elements for fixing the muzzle brake to a weapon barrel ( 4 ) having a forward muzzle end face with external coupling threading ( 9 ) in the external surface of the forward end of the barrel, and an externally cylindrical rest surface ( 7 ) between the external threading and the muzzle end face, the muzzle brake ( 5 ) having internal coupling threading ( 13 ) for engaging external coupling threading on a weapon barrel, a radially extending rest wall ( 15 ) for abutting the end face ( 10 ) of a weapon barrel muzzle, and an internally cylindrically rest surface ( 14 ) for fitting snugly over an external rest surface on a weapon barrel, and locking stop elements ( 16-19 ) for preventing rotation of the muzzle brake with respect to a weapon barrel.

Description:
The present invention relates to means for affixing a muzzle brake to the barrel of medium or large caliber firearm. 
     BACKGROUND OF THE INVENTION 
     To reduce stresses exerted by the combustion gases of the propellant charge of a munition in a weapon, it is well known to attach a muzzle brake to the free end of the arm&#39;s barrel to generate a force opposing those caused by the gases. The widely used muzzle brakes, in particular for big artillery guns, are relatively heavy and thereby impair the weapon&#39;s balance. In general such muzzle brakes are affixed by means of threads cooperating with components such as a mating nut, a spring washer, a pin and the like. The weights and the costs of these components are significant. Moreover the mechanical strength of the barrel is decreased by a channel receiving the pin, especially when this pin projects beyond the barrel tip, and related machining on the barrel and brake further increase the costs of such designs. 
     Illustratively the French Patent document 2,718,839A discloses a muzzle brake completely enclosing the free end of a weapon barrel. This muzzle brake is affixed to the barrel by threads, a lock nut making it possible to fix their relative axial positions. A screw-tightened pin makes the muzzle brake non-rotational relative to the barrel. 
     Swiss Patent document 240,479A and French patent document 715,769A discuss a muzzle brake screwed onto the front end of a weapon barrel. This brake extends the barrel and rests on its front face. Neither document describes any stop means. 
     BRIEF SUMMARY OF THE INVENTION 
     The objective of the present invention is to create a fixation En device for a muzzle brake on a weapon barrel, wherein the affixation is implemented using a lesser number of elements. 
     Accordingly, an object of the invention is a fixation device for a muzzle brake on a weapon barrel by means of a threaded coupling, the muzzle brake comprising a rest surface cooperating with the front end face of the barrel, said fixation device being characterized in that the barrel is fitted with a front cylindrical rest surface situated ahead of the threaded coupling cooperating with a corresponding rest surface of the brake assuring brake centering, and in that it comprises at least one stop precluding rotation and situated between the muzzle brake and the barrel. 
     In one feature of the invention the barrel comprises a rear rest surface cooperating with a matching rest surface of the brake and situated opposite the front rest surface relative to the threaded coupling. 
     Another feature of the invention is a stop situated near a centering rest surface and comprising at least a tightening screw mounted transversely between the muzzle brake and the barrel. That screw presses against a flat surface in the thickness of the barrel and comprises a rotation-precluding stop which may be a locknut. 
     Advantageously the tightening screw and the flat surface are configured in such a way that tightening the screw prestresses the threaded coupling while generating an additional tightening torque exerted by the muzzle brake on the barrel. 
     Another feature of the invention is the axis of the tightening screw running parallel to a barrel diameter and transversely to the flat surface, with the screw axis situated a distance D from the barrel axis approximately 0.3 to 0.7 times the length of the outside radius of the barrel. Preferably two tightening screws are configured symmetrically to the barrel axis. 
     In another embodiment of the invention the fixation device of a muzzle brake comprises a shim situated between the barrel&#39;s front end face and the wall of the muzzle brake. 
     The advantage of the fixation device of the invention for a muzzle brake is its simplicity, reducing its overall weight. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Other features, details and advantages of the invention are elucidated in the following illustrative description and in relation to the attached drawings. 
     FIG. 1 is half an axial cross-sectional view of a weapon barrel and a the muzzle brake of the invention; 
     FIG. 2 is a diametric cross-sectional view of the barrel and muzzle brake in the area of the tightening bolts and along the plane AA of FIG. 1; and 
     FIG. 3 is a half of an axial cross-sectional view showing another embodiment of the fixation device of the invention. 
    
    
     DETAILED DESCRIPTION 
     FIG. 1 shows a fixation device  1  in partial axial section along the axis  2  of the barrel  3  of a weapon (not fully shown). The end  4  of the barrel  3  seats a muzzle brake  5  conventionally comprising vanes  6  for directing the combustion gases of a propellant charge. The end  4  of the barrel  3  comprises a cylindrical front rest surface  7  and threading  9 . The front end face  10  of the barrel is substantially perpendicular to the axis  2 . The muzzle brake  5  comprises an elongated tubular stub  11  which will engage barrel end  4 . Stub  11  is fitted with threading  13  meshing with threading  9 , and a front rest surface  14  cooperating with the barrel rest surface  7  to assure centering. The brake also comprises a transverse inner wall  15  that will contact the barrel&#39;s front end face  10 . When the wall  15  rests against the barrel&#39;s front end face  10 , the muzzle brake as shown will have been fully screwed-on. In this manner no play remains between the barrel&#39;s front end face  10  and the wall  15 . Thus, propulsion gases generated by a propellant charge are prevented from passing through the threads. As a result the muzzle brake of the invention offers improved sealing over the muzzle brakes of the known state of the art. 
     Vanes  6  of muzzle brake  5  are configured in such manner that the combustion gases of a munition propellant charge will be evacuated sideways in a horizontal plane relative to the weapon barrel. For that purpose and in known manner, the first turn of the thread  9  is directed relative to positioning means on the weapon (not shown), for example relative to a pin groove linking the breech and the barrel, the first turn of the thread  13  of the muzzle brake being directed relative to the vanes  6 . 
     The threads  9  and  13  are shown in a so-called trapezoidal “artillery” shape, though any other threading form also may be used. 
     FIG. 2 is a radial cross-section of barrel  3  in the zone of the means blocking rotation of the muzzle brake relative to the barrel. These means are situated in the zone of the centering rest surfaces  7  and  14  and comprise two tightening bolts  16  screwed into threads  17  in said brake and resting against a flat surface  18  on the outside of the barrel  3 , perpendicular to the thread axis  25 . Illustratively each bolt  16  is prevented from rotating by a locking nut  19  housed in a cut  27 . These bolts  16  are configured as a function of the direction of the pitch of the threads  9  and  13  in such a way that tightening these bolts prestresses the threaded coupling by generating an additional tightening torque exerted by the muzzle brake on the barrel. 
     In the embodiment shown in FIG. 2, the bolts  16  are situated in the quadrants S′ and is S′ bounded by the two mutually perpendicular barrel diameters  21  and  22 . The respective axes  25  and  26  of the bolts are parallel to barrel diameter  21 , and tightening the bolts biases the muzzle brake to rotate clockwise corresponding to a right-handed thread. 
     The bolt axis is located a distance D from the axis  28 . Advantageously and to implement an appropriate locking torque while retaining the mechanical strength of the barrel in the vicinity of machined flat surface  18 , the distance D is about 0.3 to 0.7 times the length of the outside radius  24  of the barrel  3 . 
     Even though in FIG. 2 two diametrically opposite locking means are shown, as preferred, nevertheless a single means may be adequate in some instances. 
     The tightening threads  17  and the flat surface  18  in the thickness of the barrel are machined in such manner that they are mutually opposite when the muzzle brake assumes the locking position on the weapon&#39;s barrel. To attain this goal, the threads  17  and the flat surface  18  are respectively directed relative to the muzzle brake&#39;s vanes  6  and created when machining the barrel position on the weapon takes place. 
     The muzzle brake is installed in the following manner. The brake is mounted around the free end of barrel  3  and then screwed-on until there is hard contact between the barrel&#39;s front end face  10  and the wall  15 . As screwing proceeds, the respective rest surfaces  7  and  14  make close contact. The orientation of the initial thread turns permits appropriately positioning the muzzle brake and its vanes  6  as well as threads  17  and the flat surfaces  18 . Thereupon the bolts  16  are tightened, and they implement a tightening and prestressing torque between the threads  13  and  9 . Next the locking nuts  19  are tightened. As a result the bolts  16  prevent loosening of the muzzle brake. 
     FIG. 3 shows a variation of the device fixing a muzzle brake  5  on a weapon&#39;s barrel  3 . This embodiment variation comprises a second centering means of the muzzle brake on the barrel. Accordingly the barrel is fitted with a second rest surface  8  cooperating with a muzzle-brake rest surface  12 , said rest surfaces being to the rear of the threaded coupling  9 ,  13 . 
     Installing the muzzle brake  5  as shown in FIG. 3 includes a shim  20  between the front end face  10  of the barrel  3  and the wall  15  of the muzzle brake  5 . The shim may assume the shape of a variable-thickness washer, the thickness being adjusted as needed when the muzzle brake is installed. In this embodiment, the initial thread turns are not configured in relation to any reference, and as a result machining the threads  9  and  13  is simplified. 
     The muzzle brake is installed in the following way. The brake is mounted around the free end of the barrel  3  and then is screwed-on until there is firm contact between the barrel&#39;s front end face  10  and the wall  15 . In general, in this position, the muzzle brake&#39;s vanes  6  are not finally directed. Next the muzzle brake is unscrewed until the vanes assume an appropriate lateral position. Thereupon the clear space between the barrel&#39;s front end face  10  and the muzzle brake&#39;s wall  15  is measured, and a shim of a thickness matching the measurement is made. The muzzle brake is withdrawn to place the shim  20  against the brake&#39;s wall  15 , and this brake then is screwed-in again until it comes to a stop, whereby the vanes  6  are then in the proper position. Finally, the bolts  16  and the locking nuts are tightened. 
     In this latter embodiment, the means preventing the muzzle brake from rotation relative to the barrel can be situated near the forward centering rest surfaces  7 ,  14 , or near the rear centering rest surfaces  8 ,  12 . 
     Only one centering means  7 ,  14  may be used in still another embodiment, and with respect to the embodiment shown in FIG. 1, two rest surfaces might be used. 
     When intervention is required, the fixation device of the invention advantageously assures very easy disassembly of the muzzle brake from the weapon&#39;s barrel. 
     Those skilled in the arts of weapon design and muzzle brake design will appreciate that various modifications in the basic form of the invention as described herein can be made without departing from the scope and spirit of the invention as defined in the following claims.