EP1584883A1

EP1584883A1 - Weapon of countermass type and means for sealing countermass

Info

Publication number: EP1584883A1
Application number: EP04445042A
Authority: EP
Inventors: Rolf Pettersson
Original assignee: Saab AB
Current assignee: Saab AB
Priority date: 2004-04-05
Filing date: 2004-04-05
Publication date: 2005-10-12
Anticipated expiration: 2024-04-05
Also published as: ATE344913T1; EP1584883B1; DE602004003126T2; DE602004003126D1; ES2275199T3

Abstract

The invention relates to a weapon (1) of countermass type and means (8) for sealing the countermass. By means of the invention, a weapon of countermass type and an openable sealing means are produced which ensure that the same opening area is formed irrespective of gas pressure generated. In this way, the opening operation of the sealing means has as little spread as possible, and optimum possibilities for small recoil spreads are created. According to the invention, an openable sealing means is provided, which comprises an annular element (10) with a folding support (11) designed with a first oblong element attached to at least two diametrally opposite contact surfaces on the inner periphery of the annular element and essentially extending through the centre of rotation of the annular element. Furthermore, a folding plate (12) is arranged to cover one opening of the annular element and seal tightly against the annular element.

Description

The present invention relates to a weapon of countermass type comprising a barrel with an ammunition part, such as a projectile or a shell, countermass for reducing the pressure around the weapon, and a charge space with a charge, which charge space is arranged between the ammunition part and the countermass, the countermass being enclosed in the barrel of the weapon between openable sealing means. The invention also relates to an openable sealing means for sealing countermass in the barrel of a weapon.
In order to increase the backward momentum and thus make possible an increase in the weight of the ammunition part without excessively high pressure being created behind the weapon, it has been known for many years to insert what is known as a countermass. When the countermass leaves the rear part of the barrel, it expands and disintegrates. A liquid cloud is formed, which is braked rapidly and produces a pressure-reducing effect adjacent to the weapon. In this connection, reference may be made to our SE patent 8205956-9 which shows an example of a weapon with countermass. Another example of a weapon with countermass is described in our Swedish patent application 0301627-6. It is a common feature of the said two patent documents that the opening which is formed into the space with the countermass under the action of the gas pressure emanating from the charging space is smaller than the diameter of the barrel and thus has a throttling effect on the gas flow. The opening area tends to vary under different circumstances and inter alia depends on the gas pressure which is generated and in turn inter alia depends on the temperature of the weapon or of the countermass container, which can vary between -40° and +60°.
A critical stage in weapons with countermass is the opening phase of the countermass container. In this regard, it is important to obtain symmetrical opening of the cover of the countermass container where all break indications contribute simultaneously to the opening operation. If any part of the cover does not open at the same time as the other parts, an asymmetrical flow is created in the countermass container, which can produce great shear forces on the barrel and also great recoil variations within the temperature range. It may also happen that fragments come away from the cover. Fragments which come away from the cover constitute a great risk behind the weapon.
The object of the present invention is to produce a weapon of countermass type and an openable sealing means which ensure that the same opening area is formed irrespective of gas pressure generated. In this way, the opening operation of the sealing means has as little spread as possible, and optimum possibilities for small recoil spreads are created.
The object of the invention is achieved by a weapon characterized in that at least one of the openable sealing means consists of an annular element with a folding support designed with a first oblong element attached to at least two diametrally opposite contact surfaces on the inner periphery of the annular element and essentially extending through the centre of rotation of the annular element, and a folding plate covering one opening of the annular element and sealing tightly against the annular element, and also an openable sealing means characterized in that it comprises an annular element with a folding support designed with a first oblong element attached to at least two diametrally opposite contact surfaces on the inner periphery of the annular element and essentially extending through the centre of rotation of the annular element, and a folding plate covering one opening of the annular element and sealing tightly against the annular element. By means of the invention, a weapon is obtained with an opening area to the countermass with an area which is essentially the same as the cross-sectional area of the barrel, which opening area is independent of gas pressure generated. At the same time, fragments are effectively prevented from coming away from the sealing means and reaching the rear outlet of the barrel with the risk of injury. The reason for this is that when the folding plate comes away from the inner periphery of the annular element, it is caught by the folding support and thus prevented from reaching the rear outlet of the barrel. By virtue of the folding plate folding around the folding support, the opening area from the charge space into the space for the countermass is affected marginally.
It is especially expedient if the sealing means which is arranged on the charge space side of the countermass consists of an annular element with a folding support and a folding plate according to the previous paragraph.
According to an expedient embodiment of the openable sealing means, the folding plate is provided with weakenings adjacent to the inner periphery of the annular element. This ensures in a simple way that the folding plate comes away from the periphery of the annular element and folds around the folding support of the annular element. In this connection, the weakenings adjacent to the inner periphery of the annular element can advantageously consist of a groove etched in the folding plate. The utilization of etching technology makes groove formation relatively uncomplicated at the same time as satisfactory accuracy in groove forming is achieved.
According to another expedient embodiment of the sealing means, the folding plate is arranged sunk into the annular element. The embodiment contributes favourably to sealing against the annular element.
According to another expedient embodiment of the sealing means, the inner periphery of the annular element is designed with a sharp edge towards the folding plate. By means of the sharp edge, separation of the folding plate from the annular element is facilitated.
According to a further expedient embodiment of the sealing means, the first oblong element of the folding support is provided with a rounded edge towards the folding plate. The rounded edge ensures that the folding plate remains held together during the folding operation around the first oblong element while avoiding cutting effects.
Another favourable embodiment of the openable sealing means is characterized in that the folding support comprises a second oblong element arranged essentially diametrally in the annular element and essentially at right angles to the first oblong element, which second element is designed with a sharp edge towards the folding plate. According to this embodiment, the second oblong element functions as a cutting element which cuts the folding plate into two parts which in turn fold around the first oblong element on their respective side of the second oblong element. The embodiment effectively prevents fragments from reaching the rear outlet of the barrel at the same time as an opening to the countermass is formed which corresponds closely to the cross-sectional area of the barrel.
In order further to guarantee the folding operation of the folding plate, the folding plate can be attached to the first elongate element of the folding support at one or more attachment points, preferably in the form of spot welds.
Further advantageous embodiments emerge from patent claims accompanying the description.
The invention will be described in greater detail below by means of a number of illustrative embodiments with reference to accompanying drawings in which:
Figure 1 shows diagrammatically in a longitudinal section a weapon of countermass type according to the invention.
Figure 2 shows in a diagrammatic exploded view in perspective a first example of the design of components forming part of the sealing means according to the invention.
Figure 3 shows a component in the form of a folding plate forming part of the sealing means according to the invention.
Figure 4 shows a central section through the sealing means parallel to the axis of symmetry of an annular element forming part of the means.
Figure 5 shows the same section as in Figure 4 after the sealing means has been opened.
Figure 6 shows in a diagrammatic exploded view in perspective a second example of the design of components forming part of the sealing means according to the invention.
The weapon 1 of countermass type shown in Figure 1 comprises a diagrammatically shown barrel 2 containing an ammunition part 3 in the form of a projectile 4, a charge space 5 with a charge 6, and a countermass 7. The countermass 7 is enclosed between a front and a rear openable sealing means 8 and, respectively, 9. A sealing means which is especially suitable as a front sealing means will be described in greater detail below with reference to Figures 2-6. A number of suitable materials are available as countermass, and solutions of salt may be mentioned as examples of suitable materials.
According to Figure 2, the sealing means 8 comprises an annular element 10 with a folding support 11 and a folding plate 12. The folding support consists of a plane plate which is fastened diametrally in the annular element by means of, for example, welding. The folding support is provided with a rounded edge 13 along that part of the folding support which faces the entrance opening of the sealing means 8 and thus the folding plate 12, see Figure 4.
As can be seen most clearly from Figure 4, the folding plate 12 is sunk into the annular element 10 by virtue of the fact that the internal diameter of the entrance side is slightly greater than that of the exit side. At the transition between the different internal diameters, an edge surface 14 is formed, against which the folding plate rests and to which it is attached by means of, for example, a welded joint. The transition between the edge surface 14 and that part of the annular element which has a slightly smaller internal diameter is designed as a sharp edge 15. If appropriate, the folding plate can be attached to the folding support, for example by a pair of spot welds 17, 18, see Figure 2. The edge surface 14 and adjacent parts of the annular element 10 and the folding plate 12 are also shown on enlarged scale in Figure 4. It can also be seen from Figure 4 that a groove 24 intended to accommodate a sealing ring, such as an O ring, can be arranged around the outer periphery of the annular element 10.
Figure 3 shows the design of the folding plate 12 on the side which faces the folding support. In this connection, the folding plate comprises an all-round groove 16 designed close to the periphery of the folding plate. The groove may have been produced by etching for example. The function of the groove is described in greater detail below.
Suitable materials for the annular element 10 and the folding support 11 may be steel or aluminium. It is proposed that the folding plate 12 be made of aluminium, stainless steel, titanium or nickel silver.
The activation operation of the weapon is described in greater detail below with reference to the figures described previously.
When the weapon is activated, a gas pressure is delivered to the sealing means 8 from the charge space. When the gas pressure reaches the pressure level at which the sealing means 8 is dimensioned to open, the folding plate is freed from the annular element by virtue of the connection breaking along the groove 16. The folding plate is caught and folded around the folding support 11 and takes up a position according to Figure 5. In this way, an opening into the countermass is brought about which introduces a very small restriction of the cross-sectional area of the barrel. The countermass 7 is now pressurized. The pressure is conveyed via the countermass 7 towards the rear sealing means 9 which opens when a predetermined bursting pressure is reached, and the countermass 7 is pushed out through the outlet 19 of the barrel 2.
In the embodiment of the sealing means 8 shown in Figure 6, the folding support 11 has been modified. Here, the folding support consists of a first elongate element 20 with a rounded edge 21 and a second elongate element 22 with a sharp edge 23 arranged at right angles to the first elongate element 21. When the pressure reaches the pressure level at which the sealing means is dimensioned to open, the folding plate 12 will be freed from the annular element along the groove 16 and folded around the rounded edge 21 of the elongate element 20 at the same time as the sharp edge 23 on the elongate element 22 cuts the folding plate into two halves.
The invention is not limited to the embodiments shown by way of example above but can undergo modifications within the scope of the following patent claims.

Claims

Weapon of countermass type comprising a barrel with an ammunition part, such as a projectile or a shell, countermass for reducing the pressure around the weapon, and a charge space with a charge, which charge space is arranged between the ammunition part and the countermass, the countermass being enclosed in the barrel of the weapon between openable sealing means, characterized in that at least one of the openable sealing means consists of an annular element with a folding support designed with a first oblong element attached to at least two diametrally opposite contact surfaces on the inner periphery of the annular element and essentially extending through the centre of rotation of the annular element, and a folding plate covering one opening of the annular element and sealing tightly against the annular element.
Weapon according to Patent Claim 1, characterized in that at least the sealing means which is arranged on the charge space side of the countermass consists of an annular element with a folding support and a folding plate according to Patent Claim 1.
Openable sealing means for sealing countermass in the barrel of a weapon, characterized in that it comprises an annular element with a folding support designed with a first oblong element attached to at least two diametrally opposite contact surfaces on the inner periphery of the annular element and essentially extending through the centre of rotation of the annular element, and a folding plate covering one opening of the annular element and sealing tightly against the annular element.
Openable sealing means according to Patent Claim 3, characterized in that the folding plate is provided with weakenings adjacent to the inner periphery of the annular element.
Openable sealing means according to Patent Claim 4, characterized in that the weakenings consist of grooves etched in the folding plate.
Openable sealing means according to any one of preceding Patent Claims 3-5, characterized in that the folding plate is arranged sunk into the annular element.
Openable sealing means according to any one of preceding Patent Claims 3-6, characterized in that the inner periphery of the annular element is designed with a sharp edge towards the folding plate.
Openable sealing means according to any one of preceding Patent Claims 3-7, characterized in that the first oblong element of the folding support is provided with a rounded edge towards the folding plate.
Openable sealing means according to any one of preceding Patent Claims 3-8, characterized in that the folding support comprises a second oblong element arranged essentially diametrally in the annular element and essentially at right angles to the first oblong element, which second element is designed with a sharp edge towards the folding plate.
Openable sealing means according to any one of preceding Patent Claims 3-9, characterized in that the folding plate is attached to the first elongate element of the folding support at one or more attachment points, preferably in the form of spot welds.
Openable sealing means according to any one of preceding Patent Claims 3-10, characterized in that the annular element comprises an all-round groove in the outer periphery of the element with sealing means preferably in the form of an O ring.
Openable sealing means according to any one of preceding Patent Claims 3-11, characterized in that the annular element and the folding support are made of metal, such as steel or aluminium.
Openable sealing means according to any one of preceding Patent Claims 3-12, characterized in that the folding plate is made of aluminium, titanium, stainless steel or nickel silver.