1. Technical Field of the Invention
The present invention relates to an arrangement for a weapon comprising a countermass for reducing the pressure around the weapon, the countermass being enclosed in a container, which is mountable in the barrel of the weapon behind an ammunition part, such as a projectile or shell, and comprising an openable cover with break indications on the ammunition part side and an openable bottom with break indications on the other side.
2. Description of Related Art
In order to increase the backward momentum and thus make possible an increase in weight of the ammunition part without excessively high pressure being created behind the weapon, it has been known for many years to introduce what is known as a countermass. A critical stage in weapons with countermass is the opening phase of the countermass container. In this connection reference might be made to our SE patents 0301626-8 and 0301627-6, which discloses examples of countermass containers with symmetrical opening of its cover, where all break indications contribute simultaneously to the opening operation. Variations in temperature and pressure of the weapon or the countermass container might, if not compensated, influence on the opening operation.
Likewise, it is important to obtain symmetrical opening of the bottom of the countermass container. In this regard it is vital that even all break indications of the bottom contribute simultaneously to the opening operation of the bottom. If any part of the bottom does not open at the same time as the other parts, an asymmetric flow is created when the countermass is leaving the countermass container, which can produce great shear forces on the barrel towards the outlet. For the good functioning of the weapon it is important that the countermass has a homogeneous form when it leaves the countermass container. Further, great recoil variations might occur within the temperature range. In case the bottom would fall apart into pieces, these would constitute a great risk behind the weapon.
Even the opening operation of the bottom depends on the temperature of the weapon or the countermass container. The operating temperature can vary between approximately −40° C. and +63° C. In order for the opening operation of the bottom to have as small a variation spread as possible and to create optimum opportunities for small recoil spreads, it is important to compensate for pressure variations.
One object of the present invention is to provide an arrangement for a weapon with a countermass container, which brings about an improved symmetrical opening operation with favourable recoil in a better way than before.
This is possible with an arrangement of the initially defined kind comprising a guiding folding support which is arranged adjacent to said openable bottom on the outside of the bottom relative to the countermass container.
Expedient improvements and developments of said arrangement appear from the appended claims and the following description.
According to an advantageous development of the arrangement the folding support is provided by means of an annular element configured to fit tightly against the outside of the countermass container and in agreement with the break indications of the openable bottom. The openable bottom is designed with a number of openable flaps and said annular element comprises a support member for each openable flap forming part of the bottom.
Introduction of the annular element with a support member for each openable flap enables the opening area in the bottom of the counter mass container be defined by folding edges formed by each base of the opened flaps as in contact with the corresponding support members.
This in turn results in as small a variation spread as possible in the opening operation of the bottom and the best opportunity for small recoil spreads has thus been created.
Further, it results in a reproducible, almost identical opening area, even if different weapons are utilized. Moreover, this makes it possible to restrict the generation of undesirable forces which might exert negative influence on the weapon, control the recoil progress and minimize the risk of an asymmetric pressurising of the countermass, each of which would affect the alignment of the weapon during the period when the shell is moving forward in the barrel. In addition, by varying the number of flaps and corresponding support members it is possible to control the opening are in the bottom of the container. Advantageously, each openable flap might be triangular and in the open state configured with free equilateral legs and a base region integral with the wall of the countermass container.
The invention will be described in more detail below by means of illustrative embodiments with reference to the accompanying schematic drawings.
The general principles of an arrangement for a weapon comprising a countermass container mentioned by way of introduction and particularly solutions to obtain symmetrical opening of the cover of the countermass container are described in our SE patents 0301626-8 and 0301627-6 and therefore not described in greater detail here. The subject matter of the present invention is related to the opening of the bottom section of the counter mass container.
One support member 18′ is allocated for each openable flap 16′ forming part of the bottom 12′ of the container.
Even in this embodiment each support member 18′ is configured with a straight folding line 20′, which constitutes a chord of the annular element 8′ and is located at a distance d2 from the centre line c. The configuration with four support members 18′ will result in a relatively small opening area a2 in the bottom 12′ of the container. The smaller the number of support members the smaller is the area of the opening in the bottom. With regard to the risk for appearance of tear-off edges in lack of guiding folding support, similar advantages are achieved as in the embodiment with eight openable flaps as illustrated in
Firstly, said folding edge 28 would be located a distance from the inside of the barrel 24, approximately the same as the outer diameter Ds of the sleeve 4, which determines the actual location of the folding line 20, which in turn depends on the number of flaps chosen, compare distance d1 in
Consequently, reproducible folding edges defining the opening area in the bottom of the container are formed in interaction between each opened flap and its corresponding support member.
Number | Date | Country | Kind |
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06124297.0 | Nov 2006 | EP | regional |