Firearm with pressure accumulator
The invention relates to a firearm with pressure accumulator for eliminating the fundamental drawbacks of known and used firearms and unifies and improves their basically advantageous properties.
The pressure in the barrels of firearms known till now is uneven. At the former part of the barrel, the pressure increases rapidly, reaches a maximum, and then decreases gradually. The barrel materials known and economically achievable do not allow the maximum gas pressure in the barrel to exceed 3000-4000 bars. Owing to the pressure drop at the farther parts of the barrel, it has no sense to apply a longer barrel than 50-60 times of the bore diameter of the barrel (the so-called calibre), since at the end of a barrel longer than that, the pressure driving the missile forward is reduced to such an extent that forces breaking the missile are larger than those accelerating it, thus the missile, instead of being faster, gets, slower. Due to the limitations mentioned above, the missile leaves the barrel of traditional firearms with a muzzle velocity of maximum 1-1.6 km/s.
In the 1960-ies, in the USA, by means of a solution elaborated in frame of the HARP program (High Altitude Research Project) and applying a guide shoe concept a muzzle velocity of 2.5-3 km/s could be achieved so that by the mediation of guide shoes missiles having smaller size than the calibre are shot out from barrels of large calibre. By using this method, the weight of the missile could be decreased to the 1/3-1/4 of the missile with traditional size, which means that the driving force acting on a unit part of the missile is increased up to 3-4 times. In this solution, the length of the barrel is 150-200 times larger than the diameter of the barrel. This method is generally applied in the developed countries for guns of tanks.
A major disadvantage of this solution is that the pressure of gases driving the missile forward is uneven, and at the same time, the missile above the calibre is difficult to move due to its extraordinarily large size and weight and it is also very expensive. In addition, the guiding shoes are quickly worn when consuming the significant part of the driving energy at every shot.
The invention is related to solving the above problems so that the major part of the gases originating from the combustion of an increased amount of gunpowder is introduced into a pressure accumulator, whereas the smaller part flows into a barrel of strongly increased length driving the missile forward, then as the missile passes through the barrel, gases
accumulated in the pressure accumulator flow into the barrel, and drive the missile along the total length of the barrel with a nearly identical pressure.
Thus, the invention consists of a firearm with pressure accumulator, which is provided with an increased amount of gunpowder and significantly increased barrel length as compared to traditional firearms.
It should be mentioned that the idea of building-in a pressure accumulator into firearms emerged recently as means for making the gas pressure in the barrel more uniform and for decreasing the repulsive force at shooting, but in these solutions the shot range could be increased only by about 20-30%, in contrast to the 500-600% increase in the shot range achievable by making use of the present invention.
There are also known solutions in which the increase of the gas pressure in the barrel is caused by exploding more charges of gunpowder simultaneously or after each other, however, these methods are not safe and very difficult to handle. The invention is described in detail on the basis of the drawings; its principal advantages as compared to former firearms are illustrated in Figures 1 and 2, whereas its embodiments are shown in Figs 3, 4, 5, 6, 7 and 8 in longitudinal sectional views.
Figure Ia shows the traditional firearm in which the gases of gunpowder charge 3 situated in the cartridge chamber accelerate directly missile 2 in barrel 1. Figure Ib illustrates the solution applying guide shoes elaborated in frame of the HARP program, in which the gases of gunpowder charge 3 drive missile 2 forward by means of guide shoe 4 in barrel 1. In this solution it is striking that the size of gunpowder charge 3 is too large in comparison with the size of missile 2. This is understandable as this solution ensures a nearly twice so high muzzle velocity, which requires the combustion of a 4 time larger amount of gunpowder as energy source. The relatively large bore diameter of barrel 1 as compared to missile 2 is also striking, the further increase of which is limited by the rapid increase of the strength stress of the guide shoes 4,
Figure Ic shows the new firearm construction according to the invention. In this solution is also the large size of gunpowder charge 3 relative to missile 2 conspicuous. This increased amount guarantees the muzzle velocity above 3 km/s achievable with this method. The gases of the increased amount of gunpowder accelerate directly missile 2, i.e. no losses due to the application of guide shoe 4 take place. The calibre of barrel 1 corresponds to the cylinder size of missile 2, just like in traditional guns, i.e. there is no need for a barrel 1 of immense mass, large calibre, which would be difficult to move. A pressure accumulator 5 ensures that the gases of the larger amount of gunpowder do not push out barrel 1. Pressure
accumulator 55 namely, takes up the excess gas appearing at the first part of barrel 1, and recuperates it at the later parts to barrel 1. A strongly lengthened barrel can ensure working of the total amount of the gas. The invention ensures maximum shooting range by applying a barrel length corresponding to a calibre of 250-300. The energy relations of the three embodiments shown in Fig. 1 are compared in the diagrams of Fig. 2.
On curve a it can be seen that in the barrels of traditional firearms the gas pressure increases steeply at the beginning then decreases definitively. The same applies for the gas pressure appearing in the solution when applying guide shoes, as illustrated by curve b, with the difference that corresponding to the larger calibre used, values belonging together are significantly larger. The solution illustrated by curve c and corresponding to the method of the invention, shows a uniform gas pressure not exceeding the value limited by the strength of the barrel material, in spite of this, however, the size of the uniform, elongated working area compares with the size of the working area characteristic for the increased calibre using guide shoes, and in some cases it even exceeds the latter by a certain value.
In the new types of firearms developed according to the invention different kinds of pressure accumulators may be used.
In Fig.3 a pressure accumulator 5 provided with a ring piston 10 is shown. The gases of gunpowder charge 3 to be combusted stream partly into accumulator space 15 through a narrowing neck 7 of a female body 8 and a bore 9. In a cylindrical space 11 developed in a breech 6, the ring piston 10 is recoiled against a spring 13 and increases accumulator space 15, thus a significant amount of the gunpowder gas streams into accumulator space 15 against the pressure of spring 13. The compression of spring 13, then its subsequent extension maintains the relatively uniform, long-lasting gas pressure in barrel 1. When missile 2 leaves barrel 1, the gas pressure in accumulator space 15 drops, and ring piston 10 is shocked forward by spring 13. A gas cushion 17 enclosed between a ring flange 18 and ring channel 16 reduces the harmful impact of this shock.
The embodiment of the pressure accumulator shown in Fig. 3 has some drawbacks. For one, ring piston 10 should be sealed both from outside and inside owing to its ring nature, this sealing is provided by seals 12 and 21. This double sealing is not efficient enough. On the other hand, ring piston 10 surrounds gunpowder charge 3 and does not allow to feed the gunpowder from the side. Gunpowder can be fed exclusively from behind, from the direction of cut-off body 19 provided with a firing connector 20, which makes high speed charging difficult.
Both high speed automatic charging from the side, and the problems with ring seals are solved in the improved embodiment shown in Fig. 4. In this solution, in breech 6, two cylindrical spaces 26 and 27 are situated symmetrically at the right and left sides. Between the two cylindrical spaces 26 and 27, in the axis if barrel 1, a charging space 33 is developed in breech 6. Charging space 33 comprises a cut-off body 31 and a twin cut-off body 32 making high speed charging from the side possible. Gunpowder gases formed at the combustion of gunpowder charge 3 flow partly to barrel 1, partly in two directions via radial bores 14: through mediating bore 22 into the accumulator space 23 at the right side, and through mediating bore 24 into the accumulator space 25 at the left side. Gases flowing into the right accumulator space 23 recoil cylindrical piston 28 against spring 30 in the right-side cylindrical space 27, whereas gases flowing into the left-side accumulator space 24 recoil the other cylindrical piston 28 against spring 29 in the left-side cylindrical space 26. Springs 29 and 30 are preferably oppositely wound spirals, and they are supported from behind by lock caps 34. When missile 2 leaves the barrel 1, gas pressure drops in both, right-side accumulator space 23 and left-side accumulator space 25, thus cylindrical pistons 28 stressed by springs 29 and 30 run forward. The cylindrical pistons 28 running forward are damped by the intrusion of brake studs 35 into the left-side brake space 36 and right-side brake space 37. The drawback of pressure accumulator according to Fig. 4 is that due to the relatively small diameters of the left-side cylindrical space 26 and the right-side cylindrical space 27, only springs 29,30 of relatively small diameters can be applied, the spring stress of which are not suitable to maintain large gas pressures used in long distance missiles. Embodiment shown in Fig. 5 is suitable for eliminating this drawback, which solves the problem of maintaining large spring force by using springs 38,39,40 of relatively large diameter and placed into each other. In its principal operation, this embodiment is identical with the former ones. A difference is, however, that gunpowder gases originating from the combustion of gunpowder charge 3 leave bascule 31 to two directions: partly via neck 7 and bore 9 to barrel 1, and partly via gas outlet bore 42 to pressure accumulator housing 43 mounted on breech 6 from behind. Preferably oppositely wound spirals springs 38,39,40 support pressure accumulator piston 43 from behind, and protection against metallic butt on at the shifting forward of pressure accumulator piston 43 is provided by a gas cushion 17 closing into ring brake space 44.
Embodiment according to Fig. 6 is capable of providing an even larger spring force by developing an open accumulator, and at the same time, due to its open structure, the movement of pressure accumulator piston 43 makes charging or other procedures possible. It should be noticed that the gun with pressure accumulator according to the invention is also capable of operating as a recoilless gun. This fact influences positively the cost of its manufacturing, its shot accuracy and speed of fire. Activities bound traditionally to the recoil of the barrel, such as feeding, should be solved in this invention in another way: electromagnetically, electropneumatically, etc. In the embodiment showed in Fig. 6, this task can be solved mechanically by the movement of accumulator piston 43. Gunpowder gases originating from the combustion of gunpowder charge 3 are led in this case also to barrel 1 forward, and to accumulator piston 43 backward. Barrel 1 is fixed in the former part of breech 6, whereas accumulator piston 43 protrudes in a sealed way into the cylindrical space found in its back part. The plate-formed supporting end 45 of accumulator piston 43 reclines against strong springs 38,39 placed into one another. Springs 38, 39 are preferably oppositely wound spirals. They recline with their opposite ends to supporting plate 47, which supporting plate 47 is fixed to bounding extensions 46 of breech 6 via bounding rods 48 by means of locknuts 49. It is obvious in this embodiment that the size of springs 38, 39 can be increased at will. These springs may be equally made of both special steel materials and different fibrous plastic materials.
A significant disadvantage of mechanical springs is their large mass and limited operation speed. The swivel inertia of large moving masses can make the pressure in barrel 1 uneven decreasing thereby the efficiency of the gun according to the invention. At the same time, swivel waves propagate e.g. in steel by a velocity of 5 km/s. At such velocities occurring in this embodiment, the durability of the springs may be reduced significantly.
In order to eliminate these disadvantages, embodiments 7 and 8 were born, in which various elastic gas media are applied as springs.
In embodiment shown in Fig.7, gases originating from the combustion of gunpowder charge 50 situated in bascule 19 fill out cylindrical space 11. This gas of 500-1000 bar pressure jolts accumulator piston 43 forwards. The gas pressure formed by combusting gunpowder charge 3 with a pressure of 3000-6000 bars jolts accumulator piston 43 backwards and keeps in equilibrium with the pressure of cylindrical space 11. This equilibrium is the reason for the long lasting, relatively even gas pressure in barrel 1. When missile 2 leaves barrel 1 , the pressure in cylindrical space 11 jolts accumulator piston 43 forwards. However, braking
pin 35 closes the bore 42 leading the gases backwards, thus accumulator piston 43 is braked without a metallic impact.
The embodiment illustrated in Fig. 8 is very similar to the former; with the difference that a gas develops the pressure in cylindrical space 11 introduced through gas connector 52 and valve 51. The gas introduced may be a neutral one of high pressure, e.g. nitrogen or air, but may also be a combustible gas, e.g. acetylene combusted in cylindrical space 11 developing thereby the high gas pressure needed.
Advantages of the new firearm according to the invention can be summarized as follows. The main advantage consists of the fact that in case of a suitably large gunpowder charge and barrel length, the muzzle velocity of the firearm according to the invention can exceed significantly those achievable with firearms known till now.
Another large advantage of the solution according to the invention is that fast combusting, brisant gunpowders with large stretching force can be used without damaging the barrel. A further advantageous property is - mainly at using self bearing rockets — that the mild, smooth acceleration in the barrel does not cause an explosion of the explosive material being in the barrel, neither are the instruments and structural parts sensitive against rattle damaged.
It is also advantageous that the repercussion acting on the missile at firing is decreased significantly; even it can be fully eliminated by choosing the appropriate ratios of the swinging masses.
The invention means a step forward almost in every size range of firearms: it can be applied e.g. in long range guns for reaching a shot distance of 4-6 km, or in air defence machine guns for fighting down targets in a height of 30-35 km by self directing rockets, and it is also applicable in intercontinental rockets of large size for reaching a shot range of 500- 1000 km.
The embodiments according to the invention applying pressure accumulator is applicable not only for increasing the shot range, but by restricting the pressure of gases originating from the combustion of the gunpowder, the missile is accelerated in the barrel smoothly and evenly making it especially well applicable for firing rockets.