The invention relates to a sealing ring for obturating a propellant charge cartridge of a self-loading rifle for caseless ammunition against one face of a firearm element. Such a sealing ring is known from published, non-prosecuted German patent application DE 10 2005 020 669 A1, corresponding to U.S. patent publication No. 2007/0028756.
The sealing ring of published, non-prosecuted German patent application DE 10 2005 020 669 A1 is a classic so-called C-ring seal (named after the C-shaped cross-section of the sealing ring). Two mutually opposite L-shaped profiles are formed by the ring opening (in cross-sectional view) and their legs that face each other form an annular sealing surface.
A conventional C-ring seal is loosely set in the stepped sealing ring seat provided for it, which means there is a certain amount of clearance in both the axial and radial directions between the sealing ring and the sealing ring seat. At the moment of ignition of the propellant charge body, the C-ring seal can therefore be thrown back towards the weapons breech face (breech), whereby the propellant chamber can be sealed to the rear. With these conventional C-ring seals, however, there was the problem that they responded too slowly with respect to the detonation characteristic of the new propellant charge body. Owing to the inertia of the C-ring seal, the clearance between the propellant charge cartridge base and the thrust base was not closed quickly enough. Therefore very fast particles were blown between the annular sealing surface of the C-ring seal and the end face of the thrust base upon ignition of the propellant charge body. This circumstance led to the sealing of the C-ring seal degrading with time. In order to solve this problem, published, non-prosecuted German patent application DE 10 2005 020 669 A1 proposes to force the sealing ring, which is stepped on the side facing away from the sealing surface, into the lower portion of the cylindrical sealing ring seat under a mechanical preload. With the C-ring seal inserted in this way, the separating gap in the axial direction between the annular sealing surface and the end surface of the breech is closed after the first pressure application. As a result of the mechanical preloading of the sealing ring in its sealing ring seat, the sealing ring adopts a stable contact position to the end face of the breech after this first pressure loading. At the next gas pressure change there is no longer a large axial separation gap between the sealing ring and the breech. A good initial axial seal is thus obtained.
Although the object of published, non-prosecuted German patent application DE 10 2005 020 669 A1 has also led to an improvement in obturation, even with this new obturation method a decreasing sealing effect was observed over time. This manifested itself in a so-called slight blowing out, i.e. leakage of propellant gases between the propellant cartridge and the breech, especially after prolonged firing sequences. The main reason for the decline in the sealing effect was viewed as contamination in the seal area - even occurring with the new obturation method. The contamination of the sealing surface occurring despite the stable contact position of the sealing ring surface to the weapon breech face was explained from the heating of the sealing ring after prolonged fire sequences and an associated bulging of the sealing ring surface towards the outside. The sealing surface contacting the area immediately around the ring opening would thus be reduced. This in turn would lead to an increased blowing out and subsequently to an increasing contamination of the sealing surface. This issue was even considered by experts to be unrecoverable, because a concave indentation of the sealing surface would have to be provided for preventive compensation of the heat-induced bulging of the sealing surface. This would have been counterproductive, however, because an open gap between the seal surface and the weapons thrust base, which would be open to the propellant chamber, would then have arisen in the cold condition of the sealing ring, and the propellant gases, together with the combustion residues contained within them, would penetrate into it. The contamination of the sealing surface that has already occurred in the cold state of the sealing ring would have the effect that sustained obturation is not possible despite the heat-related compensation of the concave indentation in the sealing ring surface.
It is accordingly an object of the invention to provide a sealing ring and a propellant charge cartridge which overcome the above-mentioned disadvantages of the prior devices of this general type, which improves the obturation of a propellant charge cartridge of a firearm for caseless ammunition against one face of a firearm element.
It was only through precision measurements of new and used sealing rings that the inventors have found that the above situation is surprisingly exactly reversed with the specific geometry of a C-ring seal: as a result of heating by one or more shots from the firearm, the initially plane parallel annular surface of the conventional sealing ring undergoes concave bulging. The propellant gases then blow into the gap formed by heating between the seal surface and the weapon's breech. The combustion residues contained in the propellant gases then accumulate on the sealing ring surface and decrease its sealing effect as a result.
Based on this new knowledge, the inventive concept has been devised that the sealing surface of the sealing ring contains a first region around the annular opening of the sealing ring and a second region around the first region, wherein the second region is set back relative to a plane tangential to the first region. In other words, the second region has a convex shape, i.e. bulging or protruding, relative to the plane-parallel alignment of a classic C-ring seal.
The bulge in the second region is compensated in a short time by the heat resulting from firing, so that the sealing ring can come into plane-parallel contact with the end face of the firearm element over the entire second region without contamination. As was demonstrated through tests with a demonstrator, a sustainable, complete suppression of the blowout can be achieved through the use of the sealing rings according to the invention.
According to a particularly preferred embodiment of the present invention, the first region of the sealing surface has the form of a planar annular surface disposed around the annular opening of the sealing ring, and the second region is in the form of a conically shaped surface adjoining the outside of the annular surface. Here, the flat annular surface is preferably arranged to be placed in plane-parallel contact with the flat end face of the firearms element at ambient temperature. Further, the conically shaped surface is preferably arranged to be placed on the flat end face of the firearms element in a plane-parallel manner after heating of the sealing ring by one or more shots from the firearm.
By the shaping of the first region of the sealing surface as a flat annular surface it is advantageously achieved that a good sealing effect of the sealing ring can also be achieved at the beginning of a firing sequence, as long as the sealing ring is still below its increased operating temperature. If the elevated first region of the sealing surface then reduces downwards or inwards upon heating of the sealing ring, the main sealing surface in the second region of the sealing surface comes to rest against the end face of the firearm element.
The quality of the obturation stands or falls on the magnitude of the angle between the planar annular surface and the conically shaped surface of the sealing ring. This angle is preferably adapted to the deformation behavior of the sealing ring when heated so that the conically shaped surface can be placed on the flat end face of the firearms element in a plane-parallel manner after heating of the sealing ring. In other words, the magnitude of the cone angle of the conically shaped surface in the cold state of the sealing ring is selected such that the cone angle is compensated to 0° by heating of the sealing ring, which means that the second portion of the sealing surface can come into plane-parallel contact with the planar end surface of the firearms element. In order to achieve this, the angle between the planar annular surface and the conically shaped area of the seal surface is in the range of 5 to 20 arc minutes. Particularly preferably, this angle is in the range of 10 to 15 arc minutes, or approximately at 0.2°.
In order to achieve a good sealing effect of the sealing ring, including at the beginning of a firing sequence, the thickness of the annulus of the flat annular surface of the sealing surface, i.e. the difference between the outer annular ring radius and the inner annular ring radius, ranges from 0.5 mm to 2 mm. Particularly preferably, the thickness ranges from 0.5 mm to 1 mm.
For the sealing effect of the sealing ring considered as a whole overall operating temperatures, it has proven to be advantageous that the ratio of the thickness of the annulus of the flat annular surface to the length of the generatrix of the truncated cone of the cone shaped area lies in the range of 1:6 to 1:4. A particularly good overall sealing effect is achieved at a ratio of 1:5.
The material from which the sealing ring is made preferably contains a metal or metal alloy. In particular, the use of high temperature resistant steels is an advantage. It is emphasized that the sealing ring according to the invention needs no flexurally elastic portions and no resiliently biased portions in order to achieve its improved sealing effect. The increased sealing effect is already achieved owing to the heating-related deformation of the sealing surface alone. However, it is of course not excluded that elastic tension of various portions of the sealing ring, such as are described for example in published, non-prosecuted German patent application DE 10 2005 020 669 A1, can also be used to supplement the sealing concept according to the invention.
The sealing ring according to the invention is preferably used in a propellant charge cartridge for an automatic firearm for caseless ammunition. Here, the propellant charge cartridge can contain one or more, preferably two, propellant chambers, which are provided with a sealing ring on each of the breech side and the projectile cartridge side.
According to a particularly preferred embodiment of the present invention, such a propellant charge cartridge contains stepped sealing ring seats, into which the seal rings, which are stepped on the side facing away from the sealing surface, are inserted to form a labyrinth seal. In this case, one or more, preferably six, springs are positioned in the sealing ring seats (preferably in recesses), which press the sealing rings against a stop overlapping the lateral edge of the sealing ring. Thus, advantageously, the clearance between the base of the propellant cartridge and the base of the breech can be variably reduced to zero (be suppressed) by a spring force (depending on the rotational position of the propellant cartridge and depending on the state of thermal expansion of the propellant charge cartridge).
It is also conceivable that the force of this spring can also be actively controlled. Thus the sealing ring could, for example, be actively pressed in a controlled manner against the thrust base just before the ignition of the propellant charge body.
Further advantageous embodiments and improvements of the invention will become apparent from the following description of preferred implementation examples of the invention. It should be noted that the invention also encompasses other embodiments which result from a combination of features that are listed separately in the patent claims and/or in the description and the figures.
Other features which are considered as characteristic for the invention are set forth in the appended claims.
Although the invention is illustrated and described herein as embodied in a sealing ring and a propellant charge cartridge, it is nevertheless not intended to be limited to the details shown, since various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims.
The construction and method of operation of the invention, however, together with additional objects and advantages thereof will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings.
Referring now to the figures of the drawing in detail and first, particularly, to
A sealing surface is formed by an upward-facing outer side of a leg of the L-shaped profile in
This sloping area of the first region A1 can be convexly curved or can slope linearly (funnel-shaped) inwards. However, an equally good mixture of these two above-mentioned options is also possible for the first region A1. Such a mixture is illustrated by way of an example in
The second region A2 encloses the first region A1 and is set back. This means that the points of the area in the second region A2 fall behind (in
The structure described above preferably contains the sealing surface of the sealing ring 100 in a state in which it has not been heated by firing rounds. It is therefore possible that the set back orientation of the second region A2 can be gradually compensated by heating during the firing of a number of rounds.
Because the first region A1 of the sealing surface is in the form of a planar annular surface, this annular surface lies entirely in the tangential plane T described above. The planar annular surface A1 makes the angle α with the conically shaped region A2. The angle α, with which the second region A2 slopes relative to the tangential plane T, and thus relative to the planar annular surface A1, is identical in magnitude to the cone angle α, i.e. to the angle of slope of the conically shaped region A2.
The magnitudes of the angle α between the planar annular surface A1 and the conically shaped region A2 and/or the cone angle α are shown greatly exaggerated for clarity in
As shown in
Finally, for explanatory purposes
Reference number 1 designates a barrel of a firearm of a preferably automatically operated weapon system with caseless ammunition and high firing rate. The weapon system contains a projectile cartridge 2, preferably with two chambers 3, 30 for accommodating projectiles 6 disposed in a storage chamber or loading chamber 11. An insertion device 8 is used to bring the projectile 6 positioned in the insertion position into the chamber 3 of the projectile cartridge 2 (see
In addition, the weapon system contains a propellant charge cartridge 4 with a plurality of chambers 5, 50, into each of which a propellant charge 7 can be introduced. Preferably, the number of chambers 5, 50 of the propellant charge cartridge 4 is the same as the number of chambers 3, 30 of the projectile cartridge 2. In the present example of
A first phase of the operating cycle of the weapon system is illustrated in
In the firing position (see
During the rotation phase of the projectile cartridge 2 and the propellant charge cartridge 4 illustrated in
In
Further cycle steps and operating situations of an automatic firearm described above for caseless ammunition can be found in international patent disclosure WO 2009/146809 A1, corresponding to U.S. patent publication No. 2011/0083548. With the aid of the sealing ring 100 according to the invention, a sustainable, complete sealing of a propellant charge cartridge of a weapon for caseless ammunition can be achieved over the entire operating temperature range.
Number | Date | Country | Kind |
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10 2010 006 606.0 | Feb 2010 | DE | national |
This application is a continuation application, under 35 U.S.C. §120, of copending international application No. PCT/EP2011/000227, filed Jan. 20, 2011, which designated the United States; this application also claims the priority, under 35 U.S.C. §119, of German patent application No. DE 10 2010 006 606.0, filed Feb. 1, 2010; the prior applications are herewith incorporated by reference in their entirety.
Number | Date | Country | |
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Parent | PCT/EP2011/000227 | Jan 2011 | US |
Child | 13539669 | US |