EP0284651B1 - Flare - Google Patents

Abstract

Flare for luminous signals, especially with a diameter of 22 mm and a minimum burn time of 12 seconds, consisting of a pressed flare composition, the flare composition preferably being fired from a 26.5 mm gun and preferably falling to earth on a parachute, and the burn time and construction being such that the flare composition has burnt out before it touches the ground, the luminous intensity amounting to at least 90,000 cd and the parachute not being damaged by the generation of heat. <IMAGE>

Description

The present invention relates to signal stars according to the preamble of claim 1, as used in particular in parachute cartridges. Such signal stars are e.g. known from US-A-2 864 311.

The signal stars can also be used with other signal cartridges.

Such parachute cartridges or light cartridges are fired from civilian or military use from guns and burn z. B. from the so-called apron lighting on the parachute in a predetermined time. In order to make the burn-up sufficiently long or to prevent the signal star from burning too quickly, conventional ammunitions have the following structure.

The actual star consists of a pressed light set, which is surrounded by a jacket in an aluminum sleeve and housed in a signal carrier. The star itself rests on an exhaust charge under which the deceleration rate and propellant rate are arranged. The latter can be surrounded by a tail unit and are located in a cartridge case with propellant charge before firing.

From US-A 2 442 528 a pyrotechnic light set has become known, which is brought out of a rocket housing and burns hanging from a parachute. The light set (signal star) is pressed and surrounded by a wrapping made of "kraft" paper or other suitable material (column 3, lines 66-68). For the production, the casing is placed in a mold and the set is pressed into it in several stages (column 6, lines 35 ff).

From US-A 3 749 019 a pressed pyrotechnic segmented set is also known which is provided with an inhibitor layer (column 5, lines 22-24). The housing of the set is divided, the part surrounding the light set remains as a casing on it when it burns.

The aforementioned sheathing made of paper, aluminum or PVC dampens the burning rate of the star.

Disadvantages are u. a. a relatively high loss of luminosity due to the sheathing and at the same time a narrowly conical burn-off image, which makes detection more difficult from unfavorable angles. In addition, the burnup is not residue-free. H. Hot slag or metal parts can fall to the floor and cause injury or fire. The gradual pressing into a shell held by a tool is complex.

The object of the present invention is therefore to improve signal stars in such a way that hot residues are largely avoided at high light output and the burn-off image is enlarged. The production itself should be much easier.

This object is achieved according to claim 1 with a signal for luminous stars, consisting of a light set pressed at a pressure of about 500-1000 N / mm² and surrounded by a sheath, in which, according to the invention, the outer sheath, when burned, consists of a synthetic resin lacquer layer with a thickness of about 0.1-0.15 mm, with the synthetic resin lacquer layer being applied to the pressed light set.

Surprisingly, luminous efficacies of 100,000 cd and above were measured for the signal stars according to the invention, the burn-up times not being shortened, the burn-off also being largely free of residues, falling hot parts could not be observed, the flame breaking through or premature burning did not occur.

The varnish coating provides an ideal seal of air humidity during storage.

When using synthetic resin varnish, layer thicknesses of about 0.1 to 0.15 have proven particularly good, with the pigment content also being important, i. H. the paints should contain pigment, preferably in an amount of 20-80% by volume. Alkyd resin lacquer, chlorinated rubber lacquer, epoxy resin lacquer, acrylate resin lacquer, oil lacquer, nitro lacquer, polyester lacquer, polyurethane lacquer and the so-called combination lacquers, in which metal oxides can be incorporated, are primarily proposed.

It is preferable to use a pigmented colored varnish, because this way the luminous color of the star can be identified at the same time.

Conventional signal stars are pressed from the set under pressures of usually 3000 bar. This often creates folds in the aluminum shell, which lead to crack formation in the set, i.e. H. this signal star would fall apart after the aluminum shell was removed.

These cracks cause splintering when burned and also lead to shorter burning times.

The present invention therefore proposes a different procedure for the production thereof, in order to achieve a reproducible predetermined burn-up on the one hand and on the other hand to improve its handling for the coating.

For this purpose, the signal stars according to the invention consist of a compressed granulate. The latter is obtained in a simple manner by mixing and kneading the set with a binder. After subsequent granulation, pressable products are obtained. The pressure must be significantly higher than conventional and 500-1000 N / mm² (with usual dimensions about 20 to 40 tons).

The signal stars produced in this way are extremely stable and free of cracks. Their combustion behavior is homogeneous, they are particularly suitable for attaching the casing in the manner described above.

Conventional sentences exist e.g. B. from an oxygen carrier, which can also be a coloring component, a fuel (metal powder, such as magnesium) and a color-deepening combustion moderator. This combustion moderator is a highly chlorine-containing substance, such as. B. post-chlorinated PVC and is added in amounts of about 10%. Surprisingly, it has been found in connection with the present invention that the luminosity of a signal star can be improved in the absence of chlorine-releasing substances if the set instead of the conventional moderators is added in amounts of only about 3% by weight. The brightness increases by at least 10% without impairing the moderation.

An extension of the burning time can also be achieved in a simple manner by adding inert mineral substances, such as in particular metal oxides, as moderators to the light set. Silicon and titanium oxides have proven particularly suitable for this.

The mineral substances can be added in amounts of 3-6% by weight, an increase in 6% mineral material resulting in an increase in the burning time of approximately 30%.

In particular, the light sets according to the invention are used in parachute cartridges. This causes the parachute lines to burn in about 4% of the cases. In order to protect the lines of the screen, it is proposed to arrange a barrier layer of non-combustible oxides, preferably of sodium nitrate, in the area of the suspension of the screen.

In a particularly advantageous manner, the suspensions and the barrier layer can be incorporated during the pressing or casting process.

An effective additional protection of the parachute lines is further achieved according to the invention in that metal threads or glass fiber fabric is spun into the parachute lines or that these consist entirely of them.

To attach the parachute, a so-called stocko cap is inserted into the parachute before it is pressed, through which a split pin is guided and spread. There is a metal perforated disc between the stock cap and the cotter pin, on which the entire set is filled and pressed. After removal from the mold, the perforated disc forms the star closure towards the parachute.

This type of attachment is considerably less expensive than the conventional one, in which the attachment by rolling up the upper edge, for. B. the casing, must be made on the cover.

In the following exemplary embodiment, the production of a coatless signal star of the color yellow is described.

The light set has the following recipe: Sodium nitrate + 1% linseed oil 37% by weight Polyolefin 3% by weight magnesium 60% by weight

The polyolefin is e.g. B. a U.S.I. Chemicals manufactured and sold under the name Microthene.

This light set was made with a binder from polychlorobutadiene 11.5% by weight and a dilution 6.6% by weight
mixed, where as polychlorobutadiene z. B. a product known under the trade name "Macroplast" can be used.

The present invention is explained in more detail with reference to the accompanying figures.

Fig. 1 shows the star according to the invention.

Fig. 2 shows the structure of a parachute cartridge manufactured according to the invention.

Fig. 1

The star consists of a set 1 pressed from granulate as described above, as well as the intermediate set 2 and the firing 3. It is covered at the bottom with an aluminum ring 4, which can also be pressed. On the head side, the star has the perforated disk 5 made of Al Cu Mg alloy, through which the cotter pin 6 extends. Below the perforated disc 5, the stock cap 7 is held by the split pin 6. The perforated disc 5 is covered with a cardboard disc 8.

On the eyelet 9 of the split pin 6 there is a chain 12 provided with fastening rings 10, 11 for attaching a parachute.

With 22 is a varnish coating with a thickness of about 0.1 mm, which was given around the pressed set by painting. This coating excludes the ingress of oxygen during combustion as well as the ingress of moisture during storage.

Fig. 2

In this figure, the entire structure of a parachute cartridge is shown as an example.

The star from FIG. 1, over which the parachute 14 is packed, is arranged in the signal carrier. On the parachute 14 are held by a stopper 15 lead disks 16 which are separated from the screen by disks 17. The signal carrier is connected by bends to a tail unit 18, the ejection charge 19 for the star being accommodated in the bends. A deceleration charge 20 and a propellant charge 21 are located below the exhaust charge 19.

The tail unit itself is located in a cartridge case (not shown) with propellant charge and primer prior to completion.

Claims (8)

1. Flares for light signals consisting of a light composition (1) surrounded by a covering (22), characterised in that the light flare composition consists of granulate pressed at pressures of about 500 - 1000 N/mm² and on this is applied as covering a thin synthetic resin lacquer layer in a thickness of about 0.1 - 0.15 mm.
2. Flare according to claim 1, characterised in that the synthetic resin lacquer contains metal oxides.
3. Flare according to claim 1 or 2, characterised in that, as synthetic resin lacquer, there is employed an alkyd resin lacquer, a chlorinated rubber lacquer, an epoxide resin lacquer, a nitrocellulose lacquer, a polyester lacquer, a polyurethane lacquer or a mixed lacquer.
4. Flare according to at least one of claims 1 to 3, characterised in that, as burning-up moderator, it contains polyolefin and/or metal oxides or other fire-retarding oxides in amounts of about 3 - 6 wt.%.
5. Flare according to at least one of claims 1 to 4, characterised in that an anchoring for a parachute, consisting of a stock cap and a split pin, is pressed in at the same time, whereby a perforated disc of metal is placed between split pin loop and flare surface.
6. Flare according to claim 5, characterised in that the metal disc consists of an Al Cu Mg alloy.
7. Flare according to at least one of claims 1 to 6, characterised in that, in the suspension region of the parachute, it has a barrier layer of non-burnable salts, such as preferably sodium nitrate, and/or a metal or flame-inhibiting material.
8. Flare according to at least one of claims 5 - 7, characterised in that the suspension for the parachute is pressed in at the same time.

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