It is a known fact that the term weapon refers to all those weapons which, regardless of their shape and dimensions, utilize, for the shot of the projectiles, the expansion force exerted by the combustion of the powder.

The powder is contained in a cartridge shell, at the top of which is fixed a projectile presenting at its back a bottom on which there is a percussion detonator, which serves to prime the explosion of the powder contained in the shell. The unit formed by the shell and the projectile is called cartridge. Since for the quick use of the firearm it is always necessary to have available an adequate stock of cartridges, these constitute a potential danger because the powder contained in the shells can explode owing to accidental reasons.

There are various situations in which said possibility can occur: first of all the case in which, during a fight, the stock of ammunitions which is near the weapon or stocked in the military depot is hit by enemy fire. It can be understood that in this case the conseguences of the explosion can be devastating especially when the weapon and the ammunitions are installed aboard naval or air crafts ^' , or on board of land self-propelled vehicles. If the weapon is installed aboard an aircraft, the danger becomes greater in case of an emergency landing of the aeroplane, since the dragging of the fuselage against the earth can easily cause the autoignition of the ammunitions powder thereby causing the explosion of the aircraft. This is the reason why in all the cases in which a pilot in flight notices functioning anomalies in his aircraft, as to suggest a landing, the pilot does not try the emergency landing, but he jumps out with his parachute, abondoning the aircraft. In this case the main inconvenience is due to the loss of the aircraft and to the damages that it can cause to property and to people because of the explosion which follows when the aircraft

crashes.

Another inconvenience of the traditional firearms is that each cartridge used by them, is rather heavy and bulky because of the shell and the powder. This is a particularly penalizing inconvenience for the aircrafts wherein weights and volumes must be reduced to a minimum. Moreover only the part of the volume and of the weight of the cartridges which corresponds to the weight and the volume of the projectiles, can be transformed into the volume of useful fire.

A further inconvenience in the use of the known cartridges is that after the shot, the shell can get stuck while it is being extracted thereby causig the jamming of the weapon and the interruption of the fire action. Not the least inconvenience of firearms is the high cost of the cartridges, which is due especially to the cost incidence of the powder, of the material and of the work for the manifacture of the cartridge shell. The purpose of the present invention is the disclosure of an automatic firearm, eliminating said inconveniences.

The main purpose of the invention is to create an automatic firearm through which the shooting of projectiles is achieved without any need for cartridges with shells filled with explosive gun powder. A further scope of the invention is to create an automatic firearm which, by using shell-less and powderless cartriges allows, when compared with the known types of weapons, the reduction of the munitions weight and volume while yielding the same volume of realizable fire. Another purpose of the invention is to create an automatic weapon which presents, under the same conditions of fire volume of the known weapons, remarkably reduced cost of operation. Another important purpose of the invention is the creation of an automatic weapon which, by using shell-less ammunitions, reduces and nearly eliminates problems of the weapon jamming while in

use.

All these purposes and others which will be better explained later are reached by an automatic firearm which, according to the main claim, is characterized in that it includes: - at least a central body comprising an explosion chamber;

- at least a rifled barrel which is attached to the central body of the weapon and lacks the cartridge chamber.

- a breechblock, sliding within a seat obtained within the central body of the weapon and located between the explosion chamber on one side and the breech of the barrel on the opposite side, wherein said breechblock presents bores for the communication of the explosion chamber with the bottom of the cartridge which is ready to be shot or with an air manifold;

- a magazine for the conveyance of the cartridges to the breechblock;

- means for the movement of the breechblock; wherein the cartridge is shot by the thrust against the bottom of the projectile, caused by the blast of an air/combustible mixture under super-critical conditions within the explosion chamber.

When the weapon of the invention is being used the shooting of the cartridge is caused by the thrust against the bottom of the cartridge, which is generated by the blast of an air/combustible mixture which is conveyed into the explosion chamber and compressed under super- critical conditions.

Advantageously, according to the invention, an automatic firearm is disclosed which, while presenting the same performance capacities of the known weapons, it also presents an increased safety of use since it shoots cartridges which have no shells and no powder.

Moreover said automatic firearm, using cartridges which have no shells and no powder, yields, under the same fire volume conditions of the traditional weapons, the advantage of being more economical to use, lighter in weight and of requiring a smaller volume thanks to the type of the ammunitions required.

According to a fpreferred embodiment of the invention, said automatic firearm comprises a barrel which is connected to the central body of the weapon and communicates with an explosion chamber located in the interior of the central body, wherein the blast of a mixture consisting of air and combustible takes place. Between the breech of the barrel and the cartridge, slides a breechblock which draws each cartridge from the magazine, arranges it coaxially to the barrel in the shooting position and, after the shot, it connects the explosion chamber with an air manifold.

According to another embodiment of the invention, the automatic weapon of the invention presents in the interior of its central body , an explosion chamber, obtained by the stroke of a piston. Further scope of applicability of the present invention will become apparent from the detailed description, given hereinafter. However it should be understood that the detailed description and specific example, while indicating a preferred embodiment of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description and from the drawing, wherein:

- Fig. 1 shows the automatic firearm with the breechblock in the position of lifting a cartridge out of the magazine; - Fig.2 represents the automatic firearm of the invention with the breechblock and the cartridge positioned coaxially to the barrel and ready to be shot;

- Fig.3 shows the automatic firearm of the invention while the projectile is being shot; - Fig. represents the automatic firearm of the invention during the shooting phase of the projectile, in the case in which the installation of a gas-air piston for the recovering of the explosion gasses for the compression of the air;

- Fig. 5 shows the automatic firearm of the invention while the air is being compressed within the explosion chamber, by the gas-

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air piston which exploits the action of the gasses which have been recovered from the preceding explosion;

- Fig.6 shows a variation of embodiment of the invention, with the breechblock lifting the cartridge out of the magazine; - Fig.7 represents the automatic firearm of Fig.6 with the breechblock and the cartridge arranged coaxially to the barrel in the shooting position;

- Fig.8 shows the variation of the automatic firearm represented in Fig.6 during the shooting of the projectile; - Fig.9 shows the variation of the automatic firearm represented in Fig.6, after the projectile has been shot, while the explosion chamber is reloaded with air;

- Fig. 10 represents a further variation of the automatic firearm of the invention, said firearm being suited to the firing of a single shot.

As can be observed in Fig. 1, the automatic firearm, indicated as a whole with 1, consists of a barrel 2 with a rifled-bore 9, whose section is cylindrical in its entire length and, therefore, it has no cartridge chamber. Barrel 2 is connected to the central body 8 of the weapon, which presents, on breech 3 of the barrel, a breechblock 4 which slides within a guiding slot 6 orthogonally to the axis 5 of the barrel. An explosion chamber 7 is located within the central body 8 of the weapon. It is positioned facing the breechblock 4 on one side and breech 3 of the barrel on the other so that it is compressed between the breechblock 4 and the inner bottom 45 of the central body 8. By analogy with the known weapons, the shooting of the cartridge by the firearm according to the invention will also be called shot.

To the automatic firearm, indicated as a whole with 1, belongs a tank 19, which has been loaded with compressed air and which is connected, through a a pipe 20, provided with a pressure reducing valve 14, to a manifold 15 into which flows the air coming from

tank 19.

As can be observed in Fig. 1, the guiding slot 6 allows the breechblock 4, to slide vertically between breech 3 of barrel 2 and the explosion chamber 7. During this movement, the breechblock 4 sets into comunication, through the bores 29 and 28 which are present in the breechblock itself, alternatively the explosion chamber 7 with the air manifold 15 through pipe 21, as can be seen in Fig. 1, or the explosion chamber 7 with the bottom of the projectile 18, placed in bore 28 of the breechblock, as can be observed in Fig.2.

The automatic firearm of the invention begins to function from the situation represented in Fig.l, wherein the breechblock 4 holds, in bore 28, projectile 18, which has been lifted out of magazine 17. Starting from said position, when the anti-clockwise rotation of the eccentric 22 releases the breechblock 24, the latter is pushed downward by the vertical pressure of spring 40 and it carries downward projectile 18, contained in the cylindric bore 28, which will be called loading opening and places it with its bottom facing the explosion chamber 7, as can be observed in Fig.2.

The exactness of the position of projectile 18 is guaranteed by the head 30 of the breechblock 4, which, when the cartridge is in the shooting position, pushes against central body 8 of the weapon which locks the projectile in position as can be observed in Fig. 2 and in Fig.3.

The explosion chamber 7 contains the air 107, previously introduced trough the hole 29 of the breechblock 4 and coming from the manifold 15, which is connected to the tank 19. In particular, the tank 19 contains air, its high pressure being diminished through the pressure reducing valve 14, before it is introduced into the manifold 15, in the interior of which it is also heated by the resistance 12. When the air is compressed and heated to certain values, flowing from the manifold 15 into the explosion chamber 7, it finds

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itself in such super critical conditions as to be able to light instantaneously a mass of nebulized combustible with which it might come into contact so as to create a blast, exactly as it happens in diesel engines. Experimental tests which have been made on a prototype of the firearm of the invention, allowed to determine which are the best conditions for the air, in order to create the blast; such conditions correspond to about 22 bars, and to a temperature of about 60 degrees centigrades. Therefore, as can be observed in Fig.2, when the eccentric 22, continuing its anticlockwise rotation agaist the head 10 of the shaft operating pump 11, which is connected to a tank of combustible (not represented in the drawing) through pipe 13, through pipe 16 and injector 23, a quantity of nebulized combustible is introduced into the explosion chamber 7. Thus a mixture, which explodes immediately is formed within the explosion chamber 7.

The gasses 207 which are produced, cause on the bottom of the projectile 18, the thrust necessary to shoot along the tube of barrel 2, as can be observed in Fig.3, and cause, therefore, the shot of the projectile.

In the meantime, the eccentric 22 has continued its anti¬ clockwise rotation and when it comes in contact again with the bottom of the breechblock 4, it pushes the latter upward, by compressing the spring 40.

The firearm returns, therefore, to the position represented in Fig.l, and the cycle begins again for a second shot, and so on. The shots stop when either the trigger or the push botton which has caused the rotation of the eccentric 22, thus causing the first shot, is released.

The immission of the comburent air into the explosion chamber 7 can be obtained by drawing it from the external environment, by using the expansion force of the gasses 207, which are produced by the shot. As can be observed in Fig.4, in this case pipe 20 preceding the

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pressure reducing valve 14, which conveys the air to manifold 15, is connected not only to tank 19, containing compressed air, but also, through pipe 32, to the air chamber 25 of a gas/air cylinder 26, its gas chamber 27, being connected to the bore 9 of the barrel 2, through pipe 31.

In this situation the first shot is obtained by using compressed air, which is contained within tank 19; thereafter, gas 207, produced by this first shot, enters through pipe 21 with direction 33, into the gas chamber 27 of the gas/air cylinder 26.

Piston 34 moves in direction 35 and compresses the mass of air 125, contained in the air chamber 25. This mass flows in direction 36, through pipe 32 and the pressure reducing valve 14, into manifold 15. Meanwhile, as can be observed in Fig. 5, breechblock 4 has returned to its opening position, thus putting into communication the explosion chamber 7 with manifold 15, so that the air 125, coming from the air chamber 25 of the gas/air cylinder 26 is conveyed into the explosion chamber 7. As can be observed, it is necessary to put a valve 37 at the outlet of tank 19, said valve being kept closed after the first shot, so as to prevent the compressed air 125, coming from the air chamber 25, from flowing into tank 19. Moreover the air chamber 25 must be provided, in the pipe 38, communicating with the external environment, with a unidirectional valve 39 preventing the air during the compression phase from exiting, but allowing the filling up of the chamber 25 with air coming from the exterior, at the end of each shot when the air 125 has been used up. From what has been described, it can be understood that the automatic firearm of the invention reaches all the proposed purposes.

First of all it has been seen how, through the automatic firearm of the invention, it is possible to shoot shell-less and powder- less cartridges, which are constituted by the single projectile

18 and this because the shooting energy is obtained by the explosion of a combustible mixture in the interior of an explosion chamber 7.

Therefore, all the dangers due to accidental ignitions and the ensuing explosions of ammunition depots for firearms, containing projectiles with shell and powder are avoided. In particular said invention eliminates the dangers due to the explosion possibilities of unused ammunitions, contained in an aircraft, because of the violent crash against the ground when the pilot is forced to an emergency landing.

Therefore the invention offers the advantage, when possible, of rescuing the aircraft by an emergency landing, without explosion dangers and without dangers due to the crash of the aicraft, since the pilot does not need to jump with his parachute thereby saving the cost and preventing the loss of the aircraft.

Moreover the invention achieves the purpose of creating an automatic firearm which occupies a smaller place and has a lighter weight for the stocking of the ammunitions, the volume of fire remaining the same as the fire obtained with the automatic firearms of the known type.

In fact the complete elimination of the shell and of its powder charge permits to save both weight and volume, which is extremely important in particular for firearms installed on board of air, and naval crafts and land self-propelled vehicles. As a conseguence of the elimination of the powder which constitutes the shooting charge of the shells, the invention has reached the purposes of obtaining a reduction of the manufacturing costs of the ammunitions and of reducing the chances of the firearm being jammed during its operation. An embodiment of the firearm of the invention, based on the same idea of solution, is represented in Fig.6, which shows that the automatic firearm, indicated as a whole with 301, which consists, like the previously described embodiment, of barrel 302, which has no shell chamber and which is connected to the central body 308 of the firearm and of breechblock 304 sliding orthogonally

to the barrel within a guiding slot 306 made in the central body 308.

The explosion chamber 307 is positioned facing the breechblock 304 and on the opposite side of the barrel 302. Said explosion chamber, in this embodiment corresponds to the front chamber of a hollow cylindrical body 350, belonging to the central body 308. In the interior of said hollow cylinder 350, there is a piston 351 which is coaxial to the axis of the hollow cylinder and divides the internal volume into a front chamber 307 and into a back chamber 352 wherein, in the interior of the latter, there is a spring 353, whose ends are respectively fixed to the bottom of the piston 351 and to the bottom of the hollow cylinder 350. As can be observed in Fig. 6, the back chamber 352 of the firearm communicates, through a pipe 354, with a tank 355, which is also connected with a bore 309 of barrel 302, through a pipe 356. Moreover, said back chamber 352 communicates with another tank 357, through a pipe 358.

On the bottom the back chamber 352 presents a valve 359, which puts into communication the interior of the chamber with the external environment.

The back chamber 352 will be called, from now on, counter- pressure chamber.

According to said embodiment variation, the firearm begins to perform, starting from the situation represented in Fig. 6, wherein the firearm has a projectile 318 in bereechblock 304 and its explosion chamber 307 is filled with air, coming from manifold 315, supplied by tank 319, through the pressure reducing valve 314. The pressure on the trigger or on the shooting push-button activates the rotation of eccentric 322, which releases the breechblock 304, which is therefore pushed downward by the spring 340, as represented in Fig.7, and places the projectile 318 in the shooting position. At this point control 360 is activated and it opens the nonreturn valve 361, which causes a compressed inert gas 457,

contained in tank 357, to flow, through the pipes 358, with direction 362, into the counter-pressure chamber 352. The pressure of such a gas acts on the bottom of piston 351, which compresses the previously sucked-in air 407 contained in the explosion chamber 307.

At the same time, spring 353, within the counter-pressure chamber 352, is stretched and it accumulates the elastic energy necessary to cause piston 351 to resume its initial position at the successive moment. When within the explosion chamber 307 the super critical conditions are reached which are ideal to cause the blast, eccentric 322 activates pump 311, which , through pipe 316 sends some combustible into the explosion chamber 307, through injector 323. The combustible mixed with air detonates and the gasses, which have been produced, cause the shot of projectile 318. At the same time, as can be observed in Fig.8, the pressure created by the shot causes the unidirectional calibrated valve 363 to open, said valve being inserted in the pipe 364 and being in communication with bore 309 of barrel 202, so that the combustion gasses 407 flow into the recovery tank 355 through said valve and said pipe.

The combusted gasses continue to flow into tank 355 as long as the pressure in its interior remains lower than the pressure in the interior of the bore of the barrel and, therefore, in the interior of the explosion chamber 307. Valve 363 closes automatically as soon as the pressure within the explosion chamber 307 is reduced because of its loss through barrel 302 and it becomes lower than the internal pressure of tank 355. At this moment the back stroke of piston 351 to its initial position, is operated by the elastic return of spring 353, which by returning to its initial position,as represented in Fig.6, drags along the piston.

While the piston (see Fig. 9) is returning to its initial position, there is still some gas 457 of tank 357 within the

conter-pressure chamber 352, which had been let in during the previous compression of the air in the explosion chamber, and which must now be expelled. For this reason, valve 359 is opened during the back stroke of piston 351, so that gas 357 is expelled through it.

While piston 351 is returning to its initial position, eccentric 322 causes the upward movement of the breechblock 304, which then receives a new projectile from the magazine, as can be observed in Fig.9. In the meantime the explosion chamber 307 is set into comunication with the manifold 315 through the suction bore 329 of the breechblock 304, so that a new cycle of air suction takes place again.

When such suction has been completed, it being the second since the firearm has begun to perform and has , therefore, fired one shot, the firearm is again in the condition wherein the breechblock 304 has arranged a new projectile in the shooting position. The shooting the second projectile exploits the gas produced by the previous shot and accumulated in tank 355. When the pressure within the counter-pressure chamber 352 has become lower than the pressure within tank 355, because of the expulsion through valve 359, valve 364 opens and lets gas 407 contained in the tank flow through pipe 365 into the conter-pressure chamber 352. As a consequence of this process a new compression phase is obtained thanks to the gasses recovered from the previous explosion.

During this new phase of compression, the exhaust valve 360 of tank 357 remains closed because the gas in the interior of the latter can only be used to obtain the first compression of the air in the explosion chamber. All the compressions for the successive shots take place, by using the pressure generated by the exhaust gasses of the shots which have been accumulated in the interior of tank 19.

The cycle of the air compression will continue automatically. When it is no longer necessary to shoot, the release of the trigger or of the push-button interrupts the flow of combustible

to the injector and, at the same time, it opens the valve discharging the pressure from the counter-pressure chamber.

Spring 353 returns to its tensionless position and the firearm is ready to begin a new shooting cycle. Each embodiment variation of the automatic firearms of the invention can be obtained in the manual single shot variation.

Said single shot variation of embodiment is represented in Fig.

10, wherein the firearm presents the explosion chamber with a fixed volume. It can be observed in Fig.10 that in this case the breechblock

504 is connected at its bottom through a pin 570 to a shaft 571 and presents at one end a counter-weight 572 with a tooth 573 in the hook of trigger 574.

It can be understood that when the trigger 574 is pressed with direction 575, the counter-weight 572 moves downwards with direction 576, causing the lowering of the breechblock 504 and bringing, therefore, the projectile 518 into the shooting position.

Meanwhile, the end 577 of the shaft 571, which is opposite to the trigger 574 activates the pump 511, which introduces the combustible into the explosion chamber 507, through pipe 578, and generates the shot.

In order to reload the firearm, it is necessary to lift shaft 571 and to hook the counter weight 572 on to trigger 574. On the basis of what has just been described, it can be understood that the embodiment variation also reaches all the proposed purposes.

The examples of the described embodiments of the invention concern a firearm wherein the detonation in the explosion chamber occurs because of the firing of the mixture due to compression. The same detonating effect is obtained also by causing the firing through a spark ( or instance through a spark plug) by modifying the composition of the detonating mixture.

In consideration of the above described advantages it becomes extremely important for the automatic firearm according to the

invention to be provided with safety devices, such as to prevent the detonation within the explosion chamber when the breechblock is placed accidentally in front of the explosion chamber, thereby obstructing it. In fact in such a case a firing of the combustible mixture would cause the firearm to explode, since the exhausts would not find any outlet.

For this purpose, as can observed in the Figures, there is in the upper part of the central body 8; 308 of the firearm a sensor 100 (see Fig.6) which senses when the head 30; 330 of the breechblock 4; 304 is pressing against the central body 8; 308 of the weapon, this being the condition wherein the breechblock presents in front of the explosion chamber the bore suited to receive the projectile. If the breechblock comprises an electric cable 101 connected with the sensor 100 (see Fig. 6) the latter sends to a monitoring circuit (not represented) the consent to shoot. Further safeties can be applied to the firearm according to the invention, for example sensors warning when there are no projectiles in the magazine, or safeties against the possibility of accidental shots which are not represented in the enclosed drawings and are not mentioned in the explanation , but which have to be considered as belonging to the scope of the invention.

Moreover, the automatic firearm of the invention can be equipped with more than one barrel, communicating with the explosion chamber.

Similarly more central bodies can be applied where the explosion chamber of each central body is connected to one or more barrels and this in order to increase the volume of fire. It is understood, however, that all ^" said variations and modifications, based on the same principle of realization of the invention, do not exceed the scope of the present invention.

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