EP0033770B1 - Protection cover for a gun barrel - Google Patents

Description

The invention relates to a protective cover for a gun barrel as a tubular jacket arranged around the outer tube wall. Such heat protection sleeves made of asbestos or textile material or also as metal tubes surrounding the gun barrel at a distance are e.g. known from DE-B-1918 422.

Known casings of this type are intended to keep environmental influences, such as wind, sun or rain, away from the gun barrel and to avoid uneven heating of the barrel when shooting. In the case of these known casings, due to their construction, it is unavoidable, or in some cases even intended, for an air gap to form between the heat protection casing and the gun barrel. The air layer in the air gap causes a build-up of heat on the top of the pipe when firing and leads to different pipe wall temperatures on the pipe circumference, which leads to a warping of the pipe and thus to a deterioration in the hit performance. The temperature differences cannot be compensated for, or can only be compensated for, a little in known casings.

The invention is therefore based on the object, while avoiding the disadvantages mentioned, to provide a protective cover which can withstand the shot loads and which protects the gun barrel from different temperatures over its circumference both due to environmental influences and due to the heating to the highest temperatures during shooting. In particular, an air gap-free connection between the gun barrel and the jacket is to be created.

The solution according to the invention consists in that, in the case of a protective cover described in the introduction, a sheath applied to the outer tube wall without an air gap lies firmly on it, in which, starting from the outer tube wall, a first heat-insulating layer and a first heat-insulating layer and then at least one further heat-insulating layer and another one thermally conductive layer follows. This sequence of layers on the one hand provides radial insulation against external influences and, on the other hand, tangential heat conduction and thus a compensation of temperature irregularities still present on the pipe circumference. This prevents heat accumulation.

Another object of the invention is to enable easy and inexpensive repair if the jacket is damaged. The sheath can therefore be designed such that the two first-mentioned inner layers form an inner shell which rests firmly on the outer tube wall of the gun and the further layers form an outer shell which can be exchangeably pushed onto the inner shell. The shape of the outer wall of the inner shell and the inner wall of the outer shell, which are adapted to one another, and the use of an elastic insulating material ensure a secure connection of the firm inner shell and the loose outer shell of the protective cover.

A particularly good connection of the casing to the gun barrel, even at the high accelerations that occur during shooting, is achieved according to the invention in that the first heat-insulating layer consists of one or more, preferably two, layers of a loose ceramic fiber applied to the barrel outer wall with an adhesive, via which a temperature-resistant plastic hose is pushed and then shrunk by the action of heat. The plastic shrink tubing serves to facilitate assembly and increases the durability of the inner jacket. A one-component cement-based adhesive is preferably used for gluing the ceramic fiber only for assembly. Polytetrafluoroethylene was chosen as a suitable plastic for the plastic shrink tube. The plastic tube can be etched on the inside and / or outside in order to achieve a better connection with the adjacent layers due to the roughening of the surface.

An outer conical aluminum tube that can be pushed over the first heat-insulating layer and is connected to the heat-insulating layer by a silicone foam layer can serve as the first heat-conducting layer. This tube can be used to bridge production-related shoulders of the gun barrel. It has a flat, slightly conical outer contour over which the replaceable outer jacket can be easily pushed. The silicone foam layer is formed after the conical tube has been pushed onto the first insulating layer in that a two-component silicone foam mass is pumped liquid into the cavity, which foams there to form a closed-pore foam layer. The air is pushed out of the cavity. To make this possible, appropriate air outlet openings must be provided during manufacture.

According to another embodiment of the invention, the first heat-conducting layer in the region of a conical part of the gun barrel can be formed by an aluminum wire, preferably pre-stressed, wound on the first heat-insulating layer, the surface of which is covered with an adhesive or a temperature-resistant plastic shrink tube. Since the gun barrel is conical in this area, the surface of the aluminum wire covered with the adhesive is also conical. The adhesive or plastic shrink tubing prevents the outer sheath from popping open and / or detaching from the wire wrapping, so that it can be replaced of the outer jacket remains possible. This embodiment is preferably used in the area of the gun barrel muzzle.

A cylindrical aluminum tube with a conical inner wall lining made of silicone foam is preferably used as the second heat-insulating layer as the second heat-conducting layer. The taper of the inner wall lining is adapted to the taper of the aluminum tube or the aluminum wire or the plastic shrink tube of the first heat-conducting layer. This creates a positive connection between the inner and outer jacket. The inner wall lining of the cylindrical tube is applied to the conical tube using an auxiliary device before it is pushed over it.

The casing can extend over the entire length of the tube or can be divided into several parts in its longitudinal direction. The exchangeable outer casing of the protective cover can be fastened using screw rings, provided that there is no contact surface on the pipe, due to the construction, on the pipe lugs. Preferably, there is a subdivision into a rear part between the gun barrel guide bushing and smoke extractor and a front part between the smoke extractor and pipe mouth. A particularly good attachment of the jacket to the gun barrel is achieved by the conical aluminum barrel being supported on the one hand against an annular surface of the gun barrel guide bushing or a screw ring in front of it, and on the other hand against an annular surface of the smoke extractor. It is not necessary to support the inner jacket because it lies firmly on the pipe, e.g. through the elastic plastic shrink tube or the pre-tensioned wire.

• Fig. 1 an einem Rohrausschnitt im hinteren Geschützrohrbereich, in
• Fig. 2 an einem Ausschnitt aus Fig. 1 in grösserem Massstab, in
• Fig. 3 an einem Rohrausschnitt im vorderen Geschützrohrbereich und in
• Fig. 4 an einem Ausschnitt aus Fig. 3 in grösserem Massstab.

The drawing shows embodiments of the new protective cover in longitudinal section, in

• Fig. 1 on a pipe section in the rear gun barrel area, in
• Fig. 2 on a section of Fig. 1 on a larger scale, in
• Fig. 3 on a tube section in the front gun barrel area and in
• Fig. 4 on a section of Fig. 3 on a larger scale.

Figures 1 and 2 show:

Two layers of ceramic fibers 3 are applied to the outer wall of the gun barrel 1 with the aid of the adhesive 2. The shrink tube 4 is located above it. A silicone foam layer 5 and the conical aluminum tube 6 above. This is followed by the silicone foam layer 9, which is firmly connected to the cylindrical aluminum tube 10. Between the aluminum tube 6 and the foam layer 9 there is the separation point between the inner and outer jacket. 1 shows around the gun barrel 1 the outer conical inner jacket 12 formed from the layers 2 to 6 and the inner conical outer jacket 11 formed from the layers 9 and 10 between a screw ring 15 of the gun barrel guide bush 13 and the smoke extractor 14.

In the embodiment according to FIGS. 3 and 4, instead of the silicone foam layer 5 and the conical tube 6, the conically wound wire 7, which is smoothed on the outside with an adhesive 8, is provided.

Instead of the wire with a round cross-section shown, one with a different cross-section, e.g. be used with a square cross section, which avoids air gaps even better.

It is essential for the invention that the new jacket can breathe in the tube when shooting and withstands the accelerations of the shot. For this purpose, the layer lying directly on the gun barrel must consist of loose material of low specific weight, which is held elastically around the barrel by the plastic hose. Such an elastic holder also results from the prestressed wire winding for the first heat-conducting layer.

It is also essential that the formation of air pockets is avoided between all layers. As a result, the penetration of asymmetrical heat flows into the jacket and down to the gun barrel is avoided and, despite the insulation, asymmetrical heat flows penetrating into the jacket are distributed over the circumference with little resistance.

Claims (8)

1. Protective casing for a gun barrel (1) in the form of a tubular jacket (11, 12) and located around the outer wall of the barrel, characterized by the jacket (11, 12) being located on and firmly connected with the outer wall of the barrel without an air gap, commencing from the outer wall of the barrel the jacket comprising a first heat-insulating layer (2-5), a first heat-conducting layer (6, 7), one further heat insulating layer (9) and a heat-conducting layer (10).

2. Casing in accordance with Claim 1, characterized by the fact that the first two layers of the jacket form an inner sheath (12) bearing against the outer wall of the barrel of the gun, the further layers forming an external sheath (11) which is removably and replaceably mounted on the inner sheath.

3. Casing in accordance with Claim 1 or 2, characterized by a first heat-insulating layer comprising one or more, preferably two, layers of a ceramic fibre (3) which is secured to the outer wall of the barrel using an adhesive agent (2) and over which a temperature-resisting synthetic plastics tube is positioned and then shrunk by the action of heat.

4. Casing in accordance with any one of Claims 1 to 3, characterized by an aluminium tube (6) of external conical shape being pushed over the first heat-insulating layer and connected, without any air gap, with the heat-insulating layer by means of a silicon foam layer (5).

5. Casing in accordance with any of Claims 1 to 3, characterized by an aluminium wire (7) which is wound, preferably with prestressing, in the zone of the conical part of the gun barrel onto the first heat-insulating layer and which forms a first heat conductive layer of which the surface is covered by an adhesive agent (8) or a temperature-resisting shrinkable plastic tube.

6. Casing in accordance with any one of Claims 1 to 5, characterized by a cylindrical aluminium tube (10) forming a second heat-conductive layer and with a conical lining (9) forming the inner wall, the lining comprising a silicon foam and forming a second heat-insulating layer, the conicity of the lining (9) of the inner wall corresponding to the conicity of the aluminium tube (6) or of the aluminium wire (7) of the first heat-conductive layer.

7. Casing in accordance with any one of Claims 1 to 6, characterized by the fact that it is subdivided into a rear portion between the gun barrel mount (13) and a smoke diffuser device (14) and a front portion between the smoke diffuser device (14) and the mouth of the barrel.

8. Casing in accordance with any one of Claims 1 to 7, characterized by the fact that the outer sheath (11) is mounted between barrel attachments to rest on one hand against an annular surface of the gun barrel mount (13) and on the other hand against an annular surface of the smoke diffuser (14).

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