FEED SYSTEM FOR LINKED AMMUNITION

Abstract: A belt of linked cartridges is supplied to a traversable gun (l0) by way of flexible chutes (l4, 22, 28). A part (26) of one of the chutes (22) is secured at its respective ends to a fixed support element (l5) and to a wall (l7) of the gun turret. A loop of the chute part (26) is supported on the element (l5) and has a length sufficient to accommodate the full range of traverse of the gun (l0).

Description: Machine guns are commonly supplied with ammunition which is linked to form a belt. The ammunition belt must either be carried in or on the gun mounting or be supplied from a relatively stationary container. In cases where the gun mounting itself is required to be small it may be impossible to locate the container in or on the mounting. Additionally, if the mounting is to be carried by a comparatively light aircraft it is desirable that the ammunition container shall be sited relatively close to the aircraft centre of gravity. Both of the foregoing constraints may require relatively long belt runs between the container and the gun. Traversing of the gun requires that the ammunition belt shall be able to form loops which do not impose excessive pull which may cause its links to break or the gun to stall. If the gun has a wide arc of traverse these loops will have large changes in their configuration and these changes should preferably be accommodated in a small volume. It is an object of the invention to provide an ammunition feed system in which the foregoing requirements are met. According to the invention a feed system for supplying a belt of linked cartridges to a traversable gun comprises a relatively fixed substantially horizontal and substantially planar element, means for guiding said belt onto said element so that said element can support cartridges, and means for guiding said belt away from said element towards the breech of said gun, the area of said element being sufficiently large as to support loops formed in said belt over the expected range of traverse of said gun. In a preferred embodiment said means for guiding said belt onto and away from said element comprise first and second flexible chutes. In a further preferred embodiment said means for guiding the belt away from said element includes means for driving said cartridges towards the breech of said gun at a speed compatible with the rate of fire of said gun. An embodiment of the invention will now be described by way of example only and with reference to the accompanying drawings in which:- Figure l shows a machine gun mounted beneath the nose of a helicopter, Figure 2 is a diagrammatic plan view of the gun and associated ammunition feed system, viewed on arrow 2 in Figure l, Figures 3 and 4 are views, corresponding to Figure 2, of the gun trained respectively clockwise and anticlockwise from the position in Figure 2, and Figure 5 is an elevation on arrow 5 in Figure 2, and Figure 6 shows details to an enlarged scale of an ammunition drive and feed detector system. As shown in Figure l a machine gun l0 is located under the nose of a helicopter ll by means of a mounting l2 which in addition to permitting the gun l0 to be elevated and lowered through a total range of 50° enables it to be traversed 90° on either side of the centre line of the helicopter ll. Ammunition linked in a belt is supplied to the gun l0 from a container l3 which is located under the helicopter l0 adjacent its centre of gravity. The ammunition is conveyed from the container l3 to the mounting l2 through a flexible chute l4 of a type commercially available from Nobles Industries Inc., St. Paul, Minnesota. The connections of the chute l4 to the mounting l2 and container l3 do not move relatively but the flexibility of the chute l4 allows for dimensional tolerances and vibration. As shown in Figure 2 the mounting l2 includes a stationary support element l5 and a rotatable turret l6 on which the gun l0 is carried. A circumferential wall l7 on the turret l6 extends approximately l20° around the turret l6 and has a L-shaped section whose shorter limb forms a horizontal flange l8. The wall l7 and the flange l8 rotate with the turret l6. The chute l4 has a 90° twist so that cartridges pass over the element l5 with their points directed downwardly towards that element. The chute l4 is secured to the element l5 at 2l and a further chute 22, having the same construction as the chute l4, has one of its ends secured at 2l to the chute l4 and is aligned therewith to receive cartridges from the chute l4. The other end of the chute 22 is secured by a bracket 23 to the wall l7 and is aligned with a cartridge driving and monitoring unit 24, to be described in detail with reference to Figure 6. The chute 22 is also secured between its ends to the turret l6 by a clamp 25, the portion 26 of the chute 22 between the clamp 25 and the location 2l resting on the element l5 as a loop, the formation of this loop on the element l5 being ensured by an arcuate guide 27. A part l9 is fixedly mounted relative to the element l5 to prevent excessive looping of the chute portions 26 during movement of the turret from the position shown in Figure 4 to the position shown in Figure 2. Between the clamp 25 and bracket 23 the chute 22 is twisted through 90° about its longest axis and is also bent through 90° as shown in Figure 2 and is directed downwardly through the aperture 20 as shown in Figure 5, so that the bracket 23 and unit 24 lie below the plane of the flange extension l9. A third flexible chute 28 is secured to an aligned with the device 24 to receive cartridges therefrom, the chute 28 being bent over and back to supply cartridges in their proper orientations to the breech of the gun l0. As shown in Figure 2 with the gun l0 directed forwardly of the aircraft ll, the looped portion 26 of the chute 22 extends only part way over the element l5. With the gun traversed at 90° to starboard, as shown in Figure 3, the loop 26 extends across the whole of the element l5 and projects therefrom, being supported by the clamp 25 and flange l8. In this position a cut-out 29 in the element l5 is superposed on the aperture 20 so that the portion of the chute 22 between the clamp 25 and bracket 23 can pass downwardly to the unit 24. With the gun l0 trained 90° to port as shown in Figure 4 the loop 26 lies almost wholly on the flange l8 and only a short run of this loop is supported by the element l5. The unit 24 is shown in Figure 6 and comprises a rigid housing 30 within which cartridges 3l can be conveyed between the chutes 22, 28. Mounted on the housing 20 is an electric motor 32 which drives a sprocket wheel 33 through an angle-drive gearbox 34. The teeth of the sprocket wheel 33 are spaced apart so as to receive and locate successive cartridges 3l. The speed of rotation of the wheel 33 is such that cartridges are moved through the unit 24 at a speed which is greater than that required by the rate of fire of the gun. As is well known the links between the cartridges l9 are such as to permit these cartridges to be accordion-folded. The housing 30 includes a portion of increased cross section by means of which a cartridge 3lA can ride over a preceding cartridge 3lB to engage a cartridge 3lC two places in advance. When this happens the cartridges 3lA and 3lC are pushed downwardly by an arm 35 biased by a torsion spring 36 to operate a switch 37 which de-energises the motor 32. The motor 32 is restarted when firing of the gun l0 pulls the cartridges 3l back into the configuration shown in the drawing. The device 24 as a whole thus maintains a cartridge feed which is consistent with the rate of fire of the gun l0 and thereby avoids the ammunition pulling on the action of the gun l0 as a result of passage through the chutes l4, 22, 28.

Claims: 1. A feed system for supplying a belt of linked cartridges (3l) to a traversable gun (l0), comprising a relatively fixed substantially horizontal and substantially planar element (l5), means (l4) for guiding said belt onto said element (l5) so that said element (l5) can support cartridges (3l), and means (28) for guiding said belt away from said element (l5) towards the breech of said gun (l0), the area of said element (l5) being sufficiently large as to support loops formed in said belt over the expected range of traverse of said gun. 2. A system as claimed in Claim l in which said means for guiding said belt onto and away from said element (l5) comprise first and second flexible chutes (l4, 28). 3. A system as claimed in Claim 2 which includes a further flexible chute (22) for guiding cartridges (3l) between said first and second chutes (l4, 28), said further chute (22) being supported by said planar elements (l5). 4. A system as claimed in any of Claims l, 2 or 3 which includes means (24) for driving said cartridges (3l) towards the breech of said gun (l0) at a speed compatible with the rate of fire of the gun (l0).

Inventors: HUGHES, RODNEY VICTOR
Applicants: LUCAS INDUSTRIES PUBLIC LIMITED COMPANY
Application year: 1986
Main classification: F41D10
IPC codes: F41A9