Ammunition of said and method of firing a projectile of said round

The present invention relates to an apparatus and method for improving the ballistic performance of a cartridge, in particular the supply chain for expelling the projectile from the cartridge.

Telescopic-sleeveless ammunition comprises a propellant charge with an axial bore or cavity, a projectile, which in its entirety is mounted in the axial bore of the charge. and an igniter placed behind the projectile. When telescopically mounted sleeveless ammunition is placed in a cannon's cartridge position or powder chamber, the projectile enclosed in a drone is not inserted into the cannon's barrel, as is the case with the projectile in a conventional cartridge, which is mounted in the cartridge position. At the initiation of the telescopic ammunition deployment, the projectile is driven forward and into the cannon's barr el. During the time interval from the initialization of the igniter until the projectile is inserted into the cannon's barrel, some of the combustion gases from the igniter and the initiated di i \ 1 .uldn in>; and leak out forward through the barrel in front of the projectile .η h mm-ka the driving force. Although tolescopic ammunition / '! is easier to handle than conventions in onel 1 ammunition, it is

7902947-6 associated with various and often more difficult problems in terms of design and firing.

The igniter must have the dual function of first propelling the projectile forward and then initiating the main propulsion charge. If the initiation of the main propulsion charge takes place prematurely, a large part of the work generated by the combustion of the main propellant charge is lost to gases, which leak out through the barrel before the projectile closes the entrance of the barrel. If the initiation of the main propulsion charge is delayed, the movement of the projectile causes the free volume of the cartridge position to increase beyond a desired optimum and reduces the propulsive force acting on the projectile. The igniter must therefore be carefully designed and have a very definite reproducible mode of action in order to achieve good performance of the telescope-like ammunition. ,

Previous attempts to control the ignition and initiation chain of telescopic sleeveless ammunition include regulating the combustion rate or chemical properties of explosives or propellants. It is known, for example, to use a gas barrier which divides the propellant charge into a front and a rear portion. The chemical composition of the gas barrier is such that it momentarily delays the flow of hot combustion gases to the front portion of the propellant charge and thereby delays the ignition of the front portion in the slope to the rear portion.

If one relies on the chemical properties of the material, however, the production becomes more difficult and expensive, since the chemical properties must be carefully regulated to determine the performance of the ammunition within the desired limits. If one '50 is dependent on the required reproducibility, the production of such ammunition can become an undesirable critical procedure. In addition, it is difficult to produce materials that can ignite ammunition within a desired time limit under different temperature conditions. The ambient temperature is known to affect the combustion rate and other chemical reactions. Because the ammunition may need to be used under conditions that vary between Arctic cold and desert heat, it has been difficult to achieve the required reliability in chemical regulation of the rivet chain for telescopic ammunition.

This is part of the problem, which is eliminated by the invention.

The present invention relates to the use of mechanical means instead of chemical ones to regulate the initiation chain for telescopic ammunition. In this case, the firing 5 provides an extremely carefully determined reproducibility within a large temperature range. Furthermore, the critical requirement to carefully reproduce the chemical composition of the propellant charges from batch to batch is reduced, thus simplifying and cheapening production.

According to an embodiment of the invention, a driven charge in the cartridge has an axial cavity, in which a guide sleeve optionally covers portions of the propellant charge which face the axial cavity, a selected portion of the propellant charge being connected to the axial cavity via a fire channel. . A projectile is mounted in the axial cavity 15 and can be fired from the cartridge. An igniter is located mainly behind the projectile and provides a firing force, which forms part of the initiation chain for launching the projectile from the cartridge. A sealing means provides a movable barrier between the igniter and the propellant charge and is adjustable between a first state, the igniter being separated from the propellant charge and ignition of the propellant charge by the igniter set is thus prevented, and a second state which provides connection between the propellant charge and the igniter via the fire channel allows initiation of the propellant charge by means of the igniter.

The sealing means may comprise, for example, a piston which, at the initiation of the ignition, is moved from a position where the fire channel is closed by means of the guide sleeve, to a front position in front of the cold channel, whereby a connection is thus provided⁷> o see from the ignition to the propellant charge.

The invention is described in more detail in the following with reference to the accompanying drawing, in which Fig. 1 shows a longitudinal section of a cartridge according to the invention; Fig. 2 shows the section after 2-2 in Fig. 1; Fig. 3 shows the rear portion 55 of the cartridge in. Fig. 1 since initiation has begun and the piston has been moved forward sufficiently to establish a connection between the main drive charge and an igniter.

As shown in Fig. 1, a cartridge 10 includes a substantially cylindrical main propellant charge 40 having a cylindrical, coaxial cavity 45, in which a substantially long projectile (kt, tapered projectile) is disposed. Behind the projectile 20 is arranged a substantially cylindrical piston 50, the longitudinal axis of which coincides with the longitudinal axis of the barrel 45. A baked open recess 52 at the rear of the piston 50 encloses an ignition charge

15 arranged to propel the piston 50 forward in the axial cavity 45, the projectile 20 also being moved forward correspondingly in the axial cavity 45. An igniter 12 is arranged behind the igniter charge 13 and is fired to ignite the igniter charge 13. The guide sleeve 30 consists essentially of a cylindrical, hollow housing surrounding the igniter 12, the igniter charge 13, and a rear portion of the projectile 20. The guide sleeve 50 is fitted in a tight fit in the axial cavity 45 of the main drive charge 40 and has four fire channels 31 arranged along the circumference with equal pitch, which are located close to and closed by the outside of the piston 50. When the igniter 12 and the ignition charge 13 are ignited, the piston 50 forward and past the old channels 31, the main drive charge 40 being exposed and ignited via the fire channels 31.

In this embodiment, reproducibility of the telescopic ammunition is achieved by physically separating the initial acceleration of the projectile and the ignition of the main propellant charge. The guide sleeve 30 activates and directs the projectile 20 towards the cannon's barrel and encloses and limits the initiation of the igniter 12 and the ignition charge 1'3, so that the initiation into the supply chain takes place at a certain volume, thereby increasing the ρ.ΐ projectile acting driving force. After the projectile begins to accelerate, the main propellant charge 40 is ignited through the fire channels 31, when the piston 50 has moved sufficiently forward in the axial cavity 45 and the fire passages 31 communicate with the cavity 45. The main propellant charge 40 is thus ignited only depending on the forward movement of the piston 50. If desired, the ignition of the main drive charge 40 can be effected by means of a firing charge 32, which is arranged between the main drive charge 40 and the piston 50 at the fire channels.

31. The firing charge 32 causes ignition of the main propellant charge 40 depending on a sufficient movement forward of the projectile 20 and the piston 50 in the axial cavity 15.

The guide sleeve 30 has four slits 53 arranged along the circumference with equal pitch, which extend rearwardly from the

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7902947-6

The leading portion of the guide sleeve 30 to a location in front of the rear end of the projectile 20. The front portion of the guide sleeve 30 thus has forwardly extending tabs 34, which are bounded on each side by the slots 33 (Figs. 1 and 2). The slots 33 in the guide sleeve 50 are arranged to minimize the pressure difference acting on the wall between the main drive charge 10 and the ignition charge 13 as a result of the main drive charge being rapidly subjected to pressure. An excessive pressure difference would cause the guide sleeve 30 to change shape and prevent firing. A guide sleeve, for example made of steel, begins to deform when the pressure difference exceeds about 28 MPa. A 1 um ini mnhy 1 sa with the same measured deforms at about 10 MPa. The four slots 33 have a length of about 19 mm. Another way would be to manufacture the guide sleeve from a frangible, combustible material, which must then be strong enough to support the projectile during take-off and enclose the main propellant charge during the first initialization phase in order to ensure a reproducible and minimal ignition delay.

The ignition of the main drive charge 40 nevertheless takes place through the fire channels 5I, when these are exposed by the movement of the piston 50, and is not regulated by the combustion of the guide sleeve.

Behind the projectile 20, the guide sleeve 30 is internally diameter-reduced to the same extent as the piston 50 for the purpose of providing a tight fit between the guide sleeve 30 and the piston 50, which is desirable to prevent forward coverage of combustion gases. Flanges 35 extending radially outwardly from the outside of the guide sleeve 50 near the fire channels 31 define a recess in which the firing charge 32 is located. The inner diameter of the guide sleeve 50 further decreases behind the piston 50 for the purpose of accessing a channel 56, which connects the igniter 12 to the bottom 15, so that the latter can be ignited by the guide sleeve 50 being widened and forming a cavity for the lumbar 12.

The piston 50 is substantially cylindrical with a flat front surface 55 which abuts a flat rear surface 22 of the projectile 20. The recess 52 in the piston 50 is open rearwardly and extends axially forward in the piston 50 towards the front surface 53. The ignition charge 15 is fitted in the recess 52 but may also extend behind the piston 50. The rearmost portion of the recess 52 has an insignificant^l! larger diameter than the main portion of the recess 52, so that

7902947-6 (>

where the rearmost wall portion of the calf 50 is slightly thinner and forms a wall piece 51 which is pressed radially outwards when the ignition charge 15 is ignited, thus soni seals the outer wall of the piston against the inner wall of the guide sleeve 30 and prevents forward leaking of combustion gases. The piston can be made in a number of different ways, e.g. of a combustible material, of plastic, made in one piece with the projectile 20, or constitute a component separate from the projectile 20.

The projectile 20 is substantially cylindrical with a forward tapered tip 23, which improves the aerodynamic properties of the projectile. The rear portion of the projectile 20 has an outer diameter which adheres closely to the inner diameter of the guide sleeve 30. To further hold the projectile 20 in the guide sleeve 30, the rear portion of the projectile 20 has a ring lock 21, in which a split reading ring is arranged.

11, which is compressed upon insertion into the guide sleeve 30 and exerts an outward pressure which holds the projectile 20 and prevents it from sliding in the guide sleeve 30. If desired, the guide sleeve 30 may have an inner ring groove which receives the read ring 11 and thus provides a additional force, soin holds the projectile 20 in the guide sleeve 30. The locking ring 11 is preferably made of a material which is sheared off when a predetermined force is exerted.

The main drive charge. 40 is enclosed by a cylindrical outer casing 44 on the cylindrical exterior and an inner casing 12 on the cylindrical inner surface about a front portion of the axial cavity 45. The inner casing 42 extends from the front end of the propellant charge 40 rearwardly along a portion of the length of the tabs 34. The rear end of the drive charge 40 between the guide sleeve 30 and the outer housing 44 is closed by means of a substantially annular bottom 14. Similarly, the leading end of the propellant charge 40 between the inner casing 42 and the outer casing 44 is closed by a substantially annular front seal 41. The rear portion of the propellant charge 40 communicates with the firing charge.

52.

The piston 50 can be made in one piece with the projectile 2D, but nm the piston and the projectile are separated from each other, the manufacture and assembly of the piston 50 is facilitated, and the effect of variation of the free space is reduced.

7902947-6 to <. · 11 minimum. When determining the cross-sectional mat of the piston 50, it is desirable that this be small enough so that a reduction in the speed of the piston at initialization is achieved and also a reduction in the possibility of volume change, should any delay in initialization occur.

In the following, the process of firing the ammunition is described. The initiation chain of the cartridge 10 comprises igniting the igniter 12 by means of a percussion pin or an electric spark, so that heat and shock waves propagate through the channel

3 (> to the ignition charge 13, which is then ignited. By igniting the igniter 12 and the ignition charge 13, a pressure is generated behind the piston 50. At a predetermined pressure, the locking ring 11 is displaced and the piston 50 is moved forward guided by the guide sleeve 30 parallel to the axial cavity 45 Due to the forward movement of the piston 50, the projectile is also moved forward. The space enclosing the combustion gases from the igniter 12 and the ignition charge 13 is carefully bounded by the wall piece 51, which sealingly closes this space, so that hot gases cannot leak forward between the outer wall of the piston 50 and the inner wall of the guide sleeve 30.

After the piston 50 has been moved far enough forward, so that the wall piece 51 is located in front of the fire ducts beer, the firing charge 32 is exposed to hot combustion gases through the kettles 1 and ignited, approximately 1 (>, 5 mm out makes a typical movement of the piston 50 in for the purpose of exposing the firing charge 32 to the flame temperature of the initiated ignition charge 13. The initiation chain of the cartridge 10 is completed by igniting the main drive charge 40 due to the ignition of the ignition charge 32. If there is no ignition charge 32, the main drive addu is ignited in Fig. 40, when the fire ducts 31 are exposed and propagates the combustion gases to the main drive charge 32. the main propellant charge 40, the projectile 20 has a velocity of about 53 m / s.

The projectile 20 leaves the cartridge 10 and is inserted into the cannon's tube, whereby in a known manner there is a tight fit between the outside of the projectile and the inner surface of the barrel, so that the hot combustion gases generated during the firing of the cartridge 10 drive the projectile through the barrel. Through this step-by-step initiation chain, an efficient, fast ocli is achieved

7902947-6 reproducible ignition of the main propellant charge 40, which is controlled by the precise positioning of the projectile during the first launch phase.

I fi.g. 3 shows how the piston 50 after the ignition of the igniter 12 and the ignition charge 13 has been moved so far forward that the wall piece S1 has passed and is in front of the fire ducts 31, which are exposed to the hot combustion gases in the axial cavity 45 behind the piston 50. thereby moved forward equally far. as the piston 50. The locking ring 11 has remained in the groove 21 of the projectile 20 and has been released from the engagement with the guide sleeve 50. The wall piece 51 still abuts the inner surface of the guide sleeve 30 so that the combustion gases from the igniter 12 and the ignition charge 13 do not enter the freed space of the cavity 45 behind the projectile 20. Should this occur, it is reduced by the igniter 12 and the ignition charge 13 raf ten.

According to an embodiment of the invention, the projectile can weigh, for example, 194.5 g and have a diameter of 25 mm. In an embodiment comprising a separate piston 50, the ignition charge 13 may consist of, for example, 1.23 g of black powder, the fire channels 31 may be located 19 mm from the rear end of the cartridge 10, the piston 50 may have a diameter of about 9.5-12.8 mm and a length of about 16.5 mm, the firing charge 32 can be made of about 1.17 g of black powder, and the main propellant charge 40 can be 50 g of CIL 5554 and 60 g of IMR 4350. When a separate piston 50 is not used, the ignition charge 13 may consist of 1.23 g of black powder, the fire channels 31 being located 12.8 mm from the rear end of the cartridge 10, and the main drive charge may be made of, for example, 115 g of CIL 1391 Λ. The inner casing 42 may advantageously be a fabric-coated phenolic resin tube having a wall thickness of about 1.3 mm. The outer casing 44 may have an outer diameter of about 45 mm and a length of 152 mm. For the outer casing 41, stainless steel is preferably used, which may have a wall thickness of about 0.5 mm. Guide sleeve 30, bottom

14, and the front seal 41 may be made of 17-4 stainless steel, which has been heat-channeled according to RC 42.

Of course, all modifications are within the scope of the invention to those skilled in the art. For example, the overlap of the guide sleeve on the projectile may be different from that described

7902947-6 above. In the same way, the dimensions and shape of the piston may deviate from what has been described above.