GB2054806A - Firing cartridges from a tube - Google Patents

Abstract

A cartridge (11) to be fired from a tube (10) comprises a military charge (13) and a casing (12) having a bottom which delimits, with the rear of the charge, a space occupied by a pyrotechnic ejector (18). The charge and the casing comprise cooperating stop means (5, 17) which cause the casing to be driven by the charge out of the tube upon firing of the cartridge when the latter has been moved to a firing location by a feeding mechanism associated with the tube. In a second embodiment, the front section of the tube (10) is pivotable so as to direct the discharged cartridges away from the vehicle, e.g. plane or hydrofoil, which carries the tube. <IMAGE>

Description

SPECIFICATION Apparatus for firing cartridges comprising a military charge from a tube The present invention relates to an apparatus comprising a tube and cartridges designed to be fired from the tube, comprising a military charge and a casing having a bottom wall which defines, with the rear of the charge, a space occupied by a pyrotechnic ejector. The apparatus is particularly, although not exclusively, suitable for launching charges from a carrier vehicle and particularly from a rapid carrier vehicle such as an aircraft or hydrofoil.

It is an object of the invention to provide an apparatus for firing cartridges at high speed and under conditions which are the same for all cartridges from a tube containing several successive cartridges leaving in the tube neither a casing nor powder combustion residues.

According to the invention, there is provided an apparatus for firing cartridges from an open end of a tube constructed to receive a stack of said cartridges which each comprise a military charge and a casing having a bottom wall which defines with the charge a space for a pyrotechnic ejector, said charge and casing comprising cooperating stop means which cause the casing to be driven by the charge out of the tube when the charge has travelled a predetermined distance with respect to the casing under the action of the ejector, and said tube being provided with means for advancing said cartridges in succession to a firing location in the tube close to the open end thereof and having means for energizing the ejector.

The charge may be provided with a pyrotechnic delay for actuation at the end of a determined time lapse and adjustable after firing of the ejector.

The casing, much lighter than the charge, is driven out of the tube by the latter when the stop means come into operating conditions; it is extracted from the tube with the charge and the combustion residues, which do not then contaminate the tube. The casing also protects the cartridge behind the cartridge which is at the firing locafion, during the firing of the ejector of the latter.

At the time of firing the ejector, the bottom wall of the casing must find a support, which may in particular be: - the stack of following cartridges and the advancing device, if the latter is positively actuated and if it is capable of resisting the thrust of the ejector, which is particularly the case if the self-propelled piston device described in UK Patent application No. 79 05634 is used; - a nonreturn device; - a bolt provided with means for retracting it so as to let a new cartridge pass after each firing.

The invention will be better understood from the description which follows of an apparatus which forms a particular embodiment thereof. The description refers to the accompanying drawings, in which: Figure 1 is a simplified diagram showing the endmost part of the apparatus, in which a cartridge is in the firing position, in cross section through a plane passing throughthe axis of the tube; Figure 2, similar to Figure 1, is a simplified diagram of a modified embodiment.

The apparatus which is partly shown in Figure 1 comprises a tube 10 having a cartridge advance device, which may have one of the constructions described in UK Patent application No. 79 05634.

The advance device (not shown) comprises for example a self-propelled piston containing an electric motor driving a gear wheel which meshes with a rack carried by the tube. By way of example of other possible embodiments, there may be mentioned the use of a cable or chain fixed to the piston, associated with a capstan supported by the end of the tube opposite that through which the cartridges are fired.

Cartridge 11 shown in Figure 1 in the firing position may be regarded as comprising a casing 12 and a military charge 13. The casing is formed as a light box of light metal or reinforced plastics material; the casing typically comprises at one end a bottom 14 and, at the other end, an internal radial flange 1 5. Charge 13 comprises a case 1 6 containing a load whose nature changes depending on the mission to be accomplished. The load may be a body of a material which, when it burns, emits a radiation whose spectral distribution is similar to that of the reactors of an aircraft and is more intense, so as to form a lure.

Case 16 is provided at the rear with an external radial flange 1 7 whose projection is the same as that of flange 15. Charge 13 is thus guided when sliding along casing 12.

Between the bottom wall of casing 12 and case 1 6 there exists a space occupied by a pyrotechnic ejector 1 8 formed by a powder charge. Ejector 1 8 is provided with igniter 19, generally electric. A pyrotechnic relay 20 equips charge 1 3 and actuates the latter with a predetermined delay with respect to the firing of ejector 1 8. So that charge 13 does not slide out untimely, it will generally be retained in casing 12 by a calibrated pin 21 proportioned to break under the thrust of the combustion gases of ejector 1 8. So that the pressure of the gases drops when charge 13 arrives at the end of its travel in casing 12, the latter is formed with gas escape openings 22, distributed in the immediate vicinity of flange 1 5.

Finally, so as to locate cartridge 11 angularly in tube 10, casing 1 2 may be fitted with guiding pegs 23 designed to slide in a longitudinal groove provided for this purpose in the tube. Thus, detonator 1 9 reliably comes opposite the igniting means 24 carried by the tube.

The tube 10 may be rectilinear or curved, depending on the type of vehicle on which it is to be mounted and the position on the vehicle. Such a tube, containing several stacked cartridges, may be placed along the root or at the ends of the wings of a military aircraft. The tube will generally be placed approximately parallel to the axis of the vehicle, for aerodynamic reasons. In the embodiment illustrated in Figure 1, the charges are ejected in a direction parallel to the axis of the aircraft. It is then sufficient for the tube to be constructed to guide the cartridges, ignite the ejector and withstand the thrust of the gases. For that purpose the tube is provided with a nonreturn device 25 retaining the casing of the endmost cartridge 11. Device 25 is placed at a distance from the open end of tube 10 approximately equal to the length of a cartridge.

When the device for feeding the cartridges has a positive movement, the anti-recoil device may be a bolt 26 which a spring biases to a retaining position and which is provided with an inclined face allowing the cartridge pushed by the feeding device to force it back into the wall of the tube. In this case, a corresponding shape will be advantageously given to the nose of the cartridges. To prevent the depression prevailing downstream of the open end of tube 10 from extracting the endmost cartridge, a resilient retaining device may be provided.

If there is used, instead of a self-propelled piston, a gas-pressure feeding device or any other device which does not positively move the stack of cartridges with accuracy, the non-return device may be of a type controlled to allow only one cartridge to pass at a time.

The apparatus also includes a control box (not shown) whose construction is more or less complex depending on the number of ejection programmes contemplated. In general, it will comprise a selector allowing operation either in a manual mode, or in automatic mode. An infrared system and a firing-rate selection switch may also be provided to complete the automatic mode. If the cartridges include a programmable relay 20, the electronic means may also comprise means for adjusting a time delay. Finally, conventional checking, alert and safety systems will be provided. They may comprise means for safety before take off, for example an aerodynamic vane which only allows firing at a speed greater than a predetermined threshold.

Whatever the embodiment, the operation is as follows. When the cartridge advance device has brought a cartridge into the firing position, as shown in Figure 1, the detonator may be ignited.

Ejector 18 projects charge 13 outwardly. When charge 1 3 is almost free of the casing 16, the exhaust gases escape through holes 22 and the pressure falls. When flanges 1 7 and 1 5 arrive in contact, charge 13, whose weight is a multiple of that of the casing (typically five to ten times), snatches the casing and drags it along, at high speed, out of the tube. After ejection, the casing may be torn away from the charge by the aerodynamic forces to which it is subjected. The charge itself is actuated by relay 20. Because of the high speed of the casing during ejection, the eddies of the slip-stream cannot cause it to strike the structure of the aircraft, which could happen if the cartridge were simply pushed by the next cartridge upon advance of the stack.

The above description makes it apparent that the invention brings substantial advantages. The apparatus may be used to eject charges behind the vehicle as a cloud of electromagnetic dipoles or "chaff" capable of jamming the homing radar of a missile directed to the vehicle or a charge which burns with a sufficiently intense and localized infrared emission so as to deceive a missile having an infrared detection head, with a high speed which removes the risk of collision with the structure of the vehicle and locates the decoy or lure at a distance for effectiveness. Only that cartridge which is at the firing location may be actuated. All cartridges of the stack are successively fired under the same conditions.

By way of example, it may be indicated that each cartridge may have a length of about 100 mm and a weight of about 500 g, the ejector being formed by a few grammes of powder.

Flanges 17 and 1 5 may project by a distance of from 1 to 2 mm for a total diameter of 46 mm.

The case may be formed from thin metal or plastic material; it may be omitted if the body to be ejected is solid.

Several tubes may obviously be located on the same vehicle and controlled independently or according to a determined programme. The charges may for example be electromagnetic lures in one tube, infrared lures in another. The two tubes may contain alternate infrared and electromagnetic lures. The apparatus may be further provided to fire sequences of two charges, one of which burns immediately and the other of which takes over after extinction of the first.

Referring to Figure 2, there is shown a modified embodiment in which the charges are not fired parallel to the axis of the aircraft but in an oblique direction, typically downwards. This result is attained without permanently increasing the aerodynamic drag of the tube. Tube 1 Oa comprises an endmost part 27 of a length corresponding to that of a cartridge, which can be tilted from a rest position (shown with a broken line) to a firing position (shown with a full line).

When the feeding device forces the stack of cartridges, the inclined face 28 of the first cartridge to be ejected 11 a pushes the nosepiece 26a of section 27 and causes it to pivot. A bolt 29 then retains section 27 in its firing position.

Cartridge 11 a continues to advance while raising a trap 30 provided with resilient return means (not shown). Trap 30 rocks the cartridge as soon as it has advanced enough for its rear end to no longer abut nosepiece 26a. Firing may then be carried out as soon as the detonator of the cartridge is in electric contact with the igniting means 24a.

The return of section 27 to its rest position, under the action of resilient return means 33, may be effected by uncocking the bolt 29. A simple solution for uncocking the bolt consists in interlocking the cartridges by coupling means 32, having a form such that they separate when the endmost cartridge 11 a pivots, and in forming support 31 of bolt 29 by a finger which projects under the pressure force exerted by a cartridge.

Provided that the feeding device has a positive movement and is connected to the last cartridge, it may move back the train after firing, release bolt 29 and cause section 27 to return to its minimum drag position under the action of its resilient return means.

That arrangement, which is possible only since all cartridges are fired from a same firing location, is of advantage on a vehicle whose shape renders axial firing difficult or dangerous.

Claims (10)

1. An apparatus for firing cartridges from an open end of a tube constructed to receive a stack of said cartridges which each comprise a military charge and a casing having a bottom wall which defines with the charge a space for a pyrotechnic ejector, said charge and casing comprising cooperating stop means which cause the casing to be driven by the charge out of the tube when the charge has travelled a predetermined distance with respect to the casing under the action of the ejector, and said tube being provided with means for advancing said cartridges in succession to a firing location in the tube close to the open end thereof and having means for energizing the ejector.

2. Apparatus according to claim 1, wherein the stop means comprise an internal flange provided at the front of the casing and an external flange provided at the rear of the charge, holes for evacuating the combustion gases of the ejector being formed in the wall of the casing at a position such that they are uncovered when the stop means come into contact.

3. Apparatus according to claim 1 or 2, wherein the charge is provided with a pyrotechnic delay for actuating the charge with a determined delay after firing of the ejector.

4. Device according to any preceding claim, wherein the tube carries, at a distance from its open end corresponding substantially to the length of a cartridge, a non-return device retaining the casing of the cartridge located at the firing location.

5. Device according to any preceding claim, wherein an endmost part of the tube, of a length corresponding to that of a cartridge, is provided with means for tilting it with respect to the rest of the tube for firing.

6. Device according to claim 5, wherein the means for inclining the endmost part of the tube are formed by a nose of said part, having an inclined face supporting the endmost part of the cartridges, whereby said end most part pivots under the action of the thrust exerted by the feeding device.

7. Apparatus according to any one of claims 1 to 6, wherein the feeding device has a positive movement and the tube is provided with a nonreturn resiliently actuated bolt allowing the cartridges to pass to the open end.

8. Apparatus according to any one of claims 1 to 6, wherein the tube carries a controlled bolt designed to form a non-return device supporting the casing of the endmost cartridge and only allowing one cartridge to pass at a time.

9. Apparatus according to any one of claims 1 to 8, wherein the cartridges are provided with means coupling them together and with the feeding device, so that they form a train movable as a whole.

10. The features of novelty described in the specification and illustrated in the drawings.