RU2812499C1 - Propellant charge for grenade - Google Patents

Abstract

FIELD: weapons.

SUBSTANCE: propellant charge for a grenade. A propellant charge for a grenade, the caliber of which is commensurate with the diameter of the pre-chamber of the grenade launcher barrel with a guaranteed minimum clearance, contains a combustion chamber with powder filling fixed on the shank of the warhead body, limited on top by a sealing gasket, which is a profile plate spring, pressed inside the combustion chamber onto a step of smaller diameter, closed at the end by a diaphragm carrying an igniter capsule and covered by a membrane, as well as by at least two annular conical undercuts of the combustion chamber, inclined in the direction opposite to the diaphragm. The total number of outlet holes in the diaphragm, located around the circumference, is determined from the relation n = k(D/d), where n is the number of outlet holes, d is the diameter of the outlet holes, D is the diameter of the outlet holes, k is an empirical coefficient. The combustion chamber is fixed to the shank of the warhead body by crimping on an anaerobic sealant.

EFFECT: increasing the functional reliability of the propellant charge for a grenade and ensuring the stability of its ballistic characteristics.

2 cl, 4 dwg

Description

The invention relates to unitary loading ammunition, and more specifically to a propellant charge for a caseless grenade launcher shot for under-barrel and hand grenade launchers.

The level of this field of technology is characterized by an artillery cartridge for a grenade launcher according to patent RU 2125226 C1, F42B 5/02.1999, containing a warhead with a leading belt, a combustion chamber in which a propellant powder charge is placed, closed by a horizontal perforated diaphragm with a membrane, a sealing gasket and a primer - igniter.

The specified cartridge differs in that the combustion chamber, closed at the end by a diaphragm carrying an igniter primer, is located in the shank of the warhead body, made to match the diameter of the barrel pre-chamber with a guaranteed minimum clearance, the sealing gasket is a profiled leaf spring that loads the propellant charge on top, and the leading belt is profiled with ready-made protrusions parallel to the axis of the warhead, the width of which is commensurate with the rifling of the barrel.

The disadvantage of the known cartridge is its unsatisfactory functional reliability, which is expressed in a decrease in the ballistic performance of the product due to the rupture of the sealing gasket fixed on the shank of the grenade warhead body by the pressure of the powder gases, which fill the volume of the combustion chamber above it. When the powder filling burns out, there may be cases when the gas pressure from above moves the sealing gasket to the membrane and blocks the perforations of the diaphragm, which prevents their kinetic release into the barrel and the achievement of a given propellant impulse of the warhead.

The noted drawback has been eliminated in the shank for the warhead of an artillery cartridge according to patent RU 2209387 C1, F42B 14/00, 2001, which, due to its technical essence and the number of matching features, was chosen as the closest analogue to the proposed propellant charge.

The shank for warheads of artillery cartridges, the caliber of which is commensurate with the pre-chamber of a grenade launcher barrel with a guaranteed minimum clearance, contains a powder-fill combustion chamber mounted on the warhead body, limited on top by a sealing gasket, which is a profile leaf spring mounted inside the combustion chamber, closed at the end by a diaphragm , carrying an igniter primer and covered with a membrane. The combustion chamber is equipped inside with a step of smaller diameter for pressing in the sealing gasket, and outside it has at least two annular conical undercuts inclined in the direction opposite to the diaphragm.

A step inside the combustion chamber ensures forceful closure of the sealing gasket when it is pressed in, which guarantees reliable interference fit and stable functioning of the propellant charge.

Independent fastening of the propellant charge on the shank of the warhead body is carried out with an axial gap relative to the sealing gasket, which allows the latter to move longitudinally in operation until it stops at the end of the grenade, creating additional volume to compensate for the excess pressure of the powder gases and thereby preventing ruptures of the material of the sealing gasket.

The undercuts on the outer surface of the combustion chamber, which is interconnected with the barrel pre-chamber, act as a gas valve for increased pressure of powder gases in the gap between them, the turbulence of which creates a seal barrier that prevents the breakthrough of powder gases along the barrel bore to the muzzle, eliminating the loss of the calculated propellant pulse.

However, the disadvantage of the prototype is a decrease in functional reliability, which is expressed in the possibility of abnormal destruction of the combustion chamber and its separation from the shank of the grenade warhead. The design of the grenade launcher uses a two-chamber caseless ballistic design, in which the combustion chamber is a high-pressure chamber, and the external volume of the barrel prechamber, behind the shank with the combustion chamber, is used as a low-pressure chamber. The practice of using grenade launcher shots shows that there is a possibility of destruction of the thin-walled high-pressure combustion chamber, due to the natural spread in the energy characteristics of the powder charge burning inside it, especially in the case of elevated operating temperatures. Destruction of the combustion chamber leads to a sharp drop in pressure in it and attenuation of the combustion process of the propellant charge, which prevents the achievement of the specified ballistic characteristics.

In addition, if the combustion chamber is destroyed at the point where the grenade warhead is attached to the shank of the body or along the tops of the undercuts on the outer surface of the combustion chamber, its separated bottom part gets stuck in the pre-chamber of the grenade launcher barrel and prevents its further operation for its intended purpose.

The technical problem to which the present invention is aimed is to increase the functional reliability of the propellant charge of a grenade launcher shot and ensure the stability of its ballistic characteristics.

The required technical result is achieved by the fact that in the known propellant charge for a grenade launcher shot, the caliber of which is commensurate with the diameter of the pre-chamber of the grenade launcher barrel with a guaranteed minimum gap, containing a combustion chamber fixed to the body of the warhead with powder filling, limited on top by a sealing gasket, which is a profile leaf spring , pressed inside the combustion chamber onto a step of smaller diameter, closed at the end by a diaphragm carrying an igniter capsule, and covered by a membrane, as well as at least two annular conical undercuts of the combustion chamber, inclined in the direction opposite to the diaphragm, characterized in that the total number of exhaust holes in the diaphragm located around the circle are determined from the relationship:

n=k(D/ d), where

n - number of outlets;

d - diameter of outlet holes;

D is the diameter of the outlet holes;

k - empirical coefficient,

and the combustion chamber is fixed to the shank of the warhead body by crimping on an anaerobic sealant.

Another feature of the proposed technical solution is that on the shank of the warhead body there are two or three radial grooves for air outlet when installing the propellant charge.

The optimal number of outlet holes in the diaphragm, as well as their geometric dimensions, were calculated according to the experimental design methodology and verified during firing tests in a ballistic track with measurements of the ballistic characteristics of the functioning of a grenade launcher round. According to the results of practical experiments, the numerical value of the empirical coefficient “k” was limited in the range of 1.5...2.75.

The distinctive features of the proposed technical solution made it possible by simple calculation to unambiguously determine the design characteristics of the propellant charge for a grenade launcher round, thereby increasing its operational reliability and ensuring the stability of its ballistic characteristics.

In a two-chamber caseless ballistic design implemented in a grenade launcher, the combustion chamber is a high-pressure chamber, and the extra-granular volume of the barrel pre-chamber, behind the shank with the combustion chamber, is used as a low-pressure chamber. The combustion chamber diaphragm ensures stable combustion of the powder charge in the combustion chamber at high pressure (100-150 MPa) and the organization of the gas-dynamic process of jet distribution of combustion products into the extra-granular volume of the barrel pre-chamber through the outlet openings of the diaphragm. Powder gases are jetted along the axis from the combustion chamber, which provides the necessary throwing impulse developed along the length of the shank.

When the empirical coefficient “k” is greater than 2.75 (more exhaust holes), the strength characteristics of the combustion chamber diaphragm decrease, leading to the possibility of destruction of the diaphragm in the area where the exhaust holes are located due to the thinning of the bridges between them.

With values of the empirical coefficient “k” less than 1.5 (fewer number of exhaust holes), destruction of the combustion chamber is possible at the point where the grenade warhead is attached to the shank of the body or at the tops of the undercuts on the outer surface of the combustion chamber, due to a sharp increase in pressure due to the natural dispersion of energy characteristics of the powder charge. In addition, the importance of individual tolerances for the manufacture of exit holes in mass production increases, leading to an increase in the spread of ballistic characteristics of the propellant charge.

The proposed propellant charge is a self-sufficient autonomous unit and is installed on the shank of the warhead of the shot by crimping on an anaerobic sealant, while excess air from the internal cavity exits through the grooves of the warhead shank, preventing the anaerobic sealant from being squeezed out by excess pressure. An additional degree of sealing increases the stability of the ballistic characteristics of the propellant charge during long-term storage and the reliability of the grenade launcher round functioning as intended.

Consequently, each feature is necessary, and their combination in a stable relationship is sufficient to achieve a novelty of quality that is not inherent in the features in isolation, that is, the technical problem posed in the invention is solved not by the sum of effects, but by a new super-effect of the sum of features.

The essence of the invention is illustrated by the drawing, which serves purely for illustration and does not limit the scope of claims of the set of features of the formula.

The drawing shows:

- in Fig. 1 - shot for a grenade launcher;

- in Fig. 2 - view A in Fig. 1;

- in Fig. 3 - propellant charge;

- in Fig. 4 - view B in Fig. 3;

A shot for a grenade launcher (Fig. 1) consists of a head fuse 1, a fragmentation warhead 2, a leading belt with ready-made rifling 3, a combustion chamber 4 of the propellant charge, installed using a permanent crimp connection onto the shank 5 of the shot warhead.

The propellant charge (Fig. 3 and 4) is assembled separately in the following sequence. The combustion chamber 4 is made in the form of a glass, the bottom of which is a diaphragm 6. On the outer surface of the combustion chamber 4 there are two ring-shaped conical undercuts 7, inclined in the direction opposite to the diaphragm. In the center of the diaphragm 6, the igniter capsule 8 is coaxially fixed. A membrane 9 is glued to the bottom of the combustion chamber 4, which covers the calibrated perforations 10 of the diaphragm 9. Next, gunpowder 11 is gradually poured onto the membrane 9 inside the combustion chamber 4, which is closed with a profiled sealing gasket 12. For axial When pressing is applied, the gasket 12 is pressed against the ring step 13 and presses the powder sample 11 without destroying its grains due to the elastic properties of the plate spring-gasket 12.

The proposed propellant charge (Fig. 3 and 4) is a self-sufficient autonomous unit of the structure of a grenade launcher shot (Fig. 1). Hermetically sealing the powder filling in the combustion chamber 4 between the sealing gasket 12 and the membrane 9 allows you to keep the gunpowder 11 dry for a long time with unchanged basic technical characteristics when storing propellant charges according to the invention separately, before assembly with warheads.

The propellant charge in the form of an autonomous assembly unit is installed on the shank 5 of the warhead of the shot using the crimping method (Fig. 2) on an anaerobic sealant, while excess air from the cavity 14 exits through the grooves 15 of the shank 5 of the warhead, preventing the sealant from being squeezed out by excess pressure.

When firing, the impulse from the igniter primer 8 ignites the gunpowder 11 in the combustion chamber 4. The combustion products of gunpowder 11 break through the material of the membrane 9 above the perforations 10 of the diaphragm 9 and are thrown into the prechamber of the grenade launcher barrel, where they accumulate to the pressure of the propellant impulse.

Powder gases through the annular gap between the prechamber and the outer surface of the combustion chamber 4 enter the annular undercuts 7, where they swirl and compact, forming a gas wedge with an obturating effect, acting as a damper that prevents the free passage of powder gases into the barrel bore.

Under the influence of the pressure of the powder gases accumulated in the pre-chamber, the shot moves forward with rotation from the interaction of the belt 3 with the rifling of the barrel. Acceleration and spin-up of the grenade occurs along the length of the combustion chamber 4, and the specified initial speed and number of revolutions are achieved.

A comparison of the proposed technical solution with identified analogues of the prior art did not reveal an identical coincidence of the set of essential features of the invention.

The proposed differences in the propellant charge for a grenade launcher, which do not directly follow from the formulation of the technical problem, are not obvious to artillery ammunition specialists.

From the above we can conclude that the invention complies with the conditions of patentability.

Claims (7)

1. A propellant charge for a grenade launcher shot, the caliber of which is commensurate with the diameter of the pre-chamber of the grenade launcher barrel with a guaranteed minimum clearance, containing a combustion chamber with powder filling fixed on the shank of the warhead body, limited on top by a sealing gasket, which is a profile leaf spring pressed inside the combustion chamber on a step of smaller diameter, closed at the end by a diaphragm carrying an igniter capsule, and covered by a membrane, as well as at least two annular conical undercuts of the combustion chamber, inclined in the direction opposite to the diaphragm, characterized in that the total number of outlet holes in the diaphragm located along circles are determined from the relation: n = k(D/d), where n - number of outlets; d - diameter of outlet holes; D is the diameter of the outlet holes; k is an empirical coefficient, and the combustion chamber is fixed to the shank of the warhead body by crimping on an anaerobic sealant. 2. A propellant charge for a grenade launcher shot, according to claim 1, characterized in that two or three radial grooves are made on the shank of the warhead body for air to escape when installing the propellant charge.

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