Patent Application
20110232473
The present invention relates to a short recoil firearm. In particular, the present invention falls within the field of semiautomatic light firearms such as pistols or rifles employed in the military or sports field (e.g. hunting, target-shooting), with projectiles, large shots, shot cartridges, etc.
It is known that there are semiautomatic firearms (i.e. capable of recalling the movable masses after the shot, ejecting the cartridge case and loading new ammunitions) in which the breechblock and the barrel carry out different recoil strokes following expansion of the gases generated by the explosion. The barrel slides backwards together with the breechblock over a first portion, of smaller extent, and then stops and the breechblock continues its stroke over a second portion, of greater extent, being disengaged from the barrel. Barrel and breechblock are brought back to the percussion position by suitable return springs. During the return travel, the breechblock causes ejection of the cartridge case and loading of a new ammunition in the barrel.
In this regard, the public document EP 1 950 520 discloses a semiautomatic smooth-bore rifle comprising a frame provided with breech, a barrel slidably mounted on the frame relative to the breech, a breechblock-slider assembly that is slidable relative to the breech, and elastic means comprising a friction spring, which means is able to oppose the translational motion of said barrel.
The Applicant has felt the need to improve the movement mechanism of the barrel and the breechblock in semi-automatic short recoil firearms first of all for ensuring a greater liability and a smaller wear of the parts carrying out a relative motion.
In fact, the Applicant has noticed that during separation between barrel and breechblock in the recoil movement and/or recoupling of these elements during return to the percussion position, the contact between the parties in motion can lead to a quick wear of the parts, giving rise, as a result, to possible seizing.
In addition, the usually helical springs that are employed for return of the barrel and/or breechblock or for damping the impulse movements of said barrel and/or breechblock can be subjected to yield, over a long period of use. As a result, the accuracy and functional qualities of the arm are compromised.
In this context, the technical task underlying the present invention is to propose a short recoil firearm overcoming the aforesaid drawbacks of the known art.
In particular, it is an object of the present invention to propose a short recoil firearm capable of ensuring movement accuracy of the parts over time, the efficiency of same being maintained substantially unchanged.
In greater detail, the present invention aims at making available a short-recoil firearm ensuring a joined and integral movement of the barrel and breechblock during a first portion of the recoil stroke and a guided decoupling of the breechblock from the barrel during a second portion of the recoil stroke.
The technical task mentioned and the aims specified are substantially achieved by a short recoil fire arm in which coupling between barrel and breechblock is obtained through a train of movable cylindrical rollers and a spirally-wound tape spring.
More specifically, in a first aspect, the present invention relates to a short recoil firearm, comprising:
The above described solution enables the relative movement between barrel and slider, while at all events maintaining, during this relative movement, a continuous mechanical coupling between said two elements through the pushing elements.
Preferably, said pushing elements comprise a plurality of cylindrical rollers disposed mutually side by side at their cylindrical surfaces. The rollers are of simple and sturdy construction and, through their sliding/rolling, ensure a smooth movement of the mechanism without any risk of seizing.
Preferably, the elastic means comprises a spirally wound tape spring connected to an end pushing element operatively connected to said plurality of pushing elements; wherein in the first configuration said end pushing element is positioned in said access. The tape spring keeps its elastic features over time without yielding, thus ensuring a constant and accurate operation of the firearm.
Preferably, the recovery chamber is shaped as an arc of a circle and, preferably, partly extends around the tape spring. The resulting structure is simple and compact.
Preferably, an operating portion of the slider slides alongside the tubular body of the barrel and is aligned with, and faces a radial portion of the barrel along the operating direction; wherein the pushing elements, at least in the first configuration, are placed between said radial portion of the barrel and said operating portion of the slider. The mechanism is positioned on the side of the barrel and is not bulky for the user.
Preferably, said radial portion of the barrel has a stop plane and the end pushing element has a stop surface; wherein, in the first configuration, the stop plane rests against said stop surface. Coupling between the barrel and the end element on said plane ensures safe locking of the elements in the return movement to the percussion position and fully closes access to the recovery chamber.
Preferably, the stop plane is inclined to an in/out direction of the access, to facilitate entry of the pushing elements in said recovery chamber or exit of the pushing elements from said recovery chamber; wherein the pushing elements during passage between the first and second configuration push against said stop plane, keeping the barrel in the backward recoil position.
Preferably, the firearm comprises an adjusting device operatively working on the tape spring to adjust the preload of said tape spring. The force exerted by the spring can be adjusted based on the features of the projectiles used.
Preferably, the firearm comprises a lock device placed nearby the access and movable between a disengaged position from said access, to allow entry or exit of the pushing elements, and an engaged position in said access, to lock the pushing elements when they are in said recovery chamber and to help disassembling of the arm.
Separation of the barrel from the support body can therefore be carried out without the risk that the rollers may fall out of the recovery chamber.
Further features and advantages of the present invention will become more apparent from the description given by way of non-limiting example of a preferred but not exclusive embodiment of a short recoil firearm, as shown in the accompanying drawings, in which:
In the accompanying drawings, a firearm that in the non-limiting example is a pistol or hand gun, has been identified with reference numeral 1.
Pistol 1 comprises, in known manner and therefore not described in detail, a main body or frame 2 provided with a grip 3 that also performs the function of projectile 4 housing, and a trigger 5 operatively connected to a hammer 6.
Mounted on the main body 2 is a barrel 7 comprising a tubular body 8 extending along an axis “X-X”. The tubular body 8 is provided with a proximal opening 9 placed in the vicinity of grip 3 and an opposite or distal opening 10. The tubular body 8 confines a chamber 11 close to the proximal opening 9, which chamber is adapted to contain a projectile 4 at a time. Barrel 7 can slide on the main body 2 carrying out a stroke S1 of few millimetres (5 mm-10 mm, for example) between a forward percussion position (
Pistol 1 comprises a slider 17 mounted on the main body 2. Slider 17 in turn comprises a breechblock 18 aligned with barrel 7 along axis “X-X” and such disposed as to face the proximal opening 9 and an operating portion 19 integral with the breechblock 18 and placed on the side of the tubular body 8. The operating portion 19 is guided in a guide defined in the main body 2, is aligned with the radial portion 12 of barrel 7 along an operating direction “Y-Y” parallel to axis “X-X” of barrel 7 and faces said radial portion 12. Slider 17 can translate on the main body 2 between a forward position, shown in
Pistol 1 further comprises a plurality of pushing elements 22 that, as in the embodiment shown, preferably consist of cylindrical rollers disposed mutually side by side at their cylindrical side surfaces. The cylindrical roller train 22, when slider 17 is in the first forward position shown in
In the embodiment shown, the two first cylindrical rollers 22 disposed close to the operating portion 19 of slider 17 are mutually secured by means of a first plate 23 on which they are both hinged around their main axes. These rollers 22 are further secured to said operating portion 19 of slider 17 through a second plate 24 having one end hinged on the first plate 23 and the opposite end hinged on the operating portion 19. The remaining cylindrical rollers 22 (five in number in the pistol shown) are not mutually linked but merely lie side by side.
The main body 2 of pistol 1, on the side of channel 20, comprises a box-shaped body 25 in which a spirally wound tape spring 26 is installed. The main body 2 extends under barrel 7 like grip 3 and in front of trigger 5. A recovery chamber 27 is confined between the tape spring 26 and an outer wall of the box-shaped body 25, which recovery chamber partly extends around said tape spring 26 and is shaped like an arc of a circle (subtending an angle of about 270°). The recovery chamber 27 and tape spring 26 extend around an axis “Z-Z” orthogonal to the operating direction “Y-Y” and preferably orthogonal to a symmetry plane of pistol 1. The recovery chamber 27 has a closed end and an opposite end that is open through an access 27a opening into the main body 2 towards barrel 7, as described in more detail in the following.
An inner end of the tape spring 26 is fastened to a pin 28 mounted on the box-shaped body 25. Rotation of pin around axis “Z-Z” allows adjustment of the tape spring 26, i.e. preload thereof to be regulated. An outer end of the tape spring 26 is fastened to an end pushing element 29 that can slide inside the recovery chamber 27 along a path shaped like an arc of a circle guided, on one side, by the radially outermost turn of said tape spring 27 and, on the other side, by the outer wall of the box-shaped body 25.
The end pushing element 29 comprises (
At the radial portion 12 of barrel 7 there is a conveyor 31 that is fixed relative to the main body 2. Conveyor 31 (
Pistol 1 further comprises a lock device 33 placed nearby the access 27a and movable between a disengaged position from said access 27a, to allow entry or exit of the pushing elements 22, and an engaged position in said access 27a, to retain rollers 22 when they are in the recovery chamber 27 and enable disassembling of barrel 7 without rollers 22 falling out. The illustrated lock device 33 is a rotatable element that is operated manually.
In use, when pistol 1 is ready to shoot with a projectile 4 in chamber 11 (
Just after percussion, by effect of the pressure generated by the bursting gases, barrel 7 and slider 17 jointly move backwards being steadily locked to each other by the train of cylindrical rollers 22 over the first stroke portion S1. The packed rollers 22 constitute a metal closure block enabling maximum exploitation of the bursting gases under expansion. When the first stroke portion S1 has been covered, the stop surface 13 of the radial portion 12 of barrel 7 stops in its backward recoil position against the stop element 14. The stop plane 16 of the radial portion 12 moves away from the stop surface 30 of the end pushing element 29 and clears access 27a opening into channel 20. This stop plane 16 is oriented like the access walls 27a. The projectile 4 comes out of barrel 7 through the distal opening 10. Rollers 22 are pushed by the operating portion 19 of slider 17 and push the end pushing element 29 into the recovery chamber 27, in turn entering said recovery chamber 27 one after the other being guided by the stop plane 16 and conveyor 31. The end pushing element 29 almost reaches the closed end of the recovery chamber 27. Opening of access 27a and entry of rollers 22 therefore disengage slider 17 from barrel 7. Barrel 7 has reached its end of stroke but slider 17 continues its recoil stroke over a portion S2 (50 mm-70 mm) that is much greater than S1. The breechblock 18 moves backwards until the end of its stroke, recocks the hammer and ejects the fired cartridge case. This action is counteracted by the tape spring 26 that during the backward movement of slider 17, is loaded, being pushed by rollers 22.
At this point, the tape spring 26 tends to run down and go back to the starting configuration. The tape spring 26 pushes the end pushing element 29 towards access 27a that in turn pushes rollers 22 out of the recovery chamber 27. Rollers 22 push the operating portion 19 of slider 17 towards the forward position and the breechblock 18 towards barrel 7. The breechblock 18, in its forward movement, introduces a new projectile 4 into chamber 11 and goes on until all rollers 22 are again aligned in channel 20 and locked between barrel 7 and slider 17. Then barrel 7 that is no longer retained in the backward position by the alternation of rollers 22 sliding against the stop plane 15, can move forward together with slider 17. The stop plane 15 is inserted into the cavity of the end pushing element 29 and stops against the stop surface 30, thus completing the closure block.
| Number | Date | Country | Kind |
|---|---|---|---|
| MI2010A000474 | Mar 2010 | IT | national |
