GB2147089A - Projectile launching - Google Patents

Abstract

A device for launching a projectile under the action of gas, eg. CO2, under pressure comprises a housing (11) having a bore (18), a projectile (13) arranged in use in the bore of the housing, a chamber (21) communicating with the bore of the housing through supply aperture(s) (22), means (28) for supplying gas under pressure to the chamber to bring the gas therein to a predetermined working pressure at which it is arranged to flow into the bore (18) through the aperture(s) (22) to propel the projectile (13) along the bore. Initially, however, it is an auxiliary supply of gas under pressure bled off from the chamber (21) which causes the projectiles (13) to move forwardly, the main supply through the aperture(s) (22) not taking effect until a seal (25) on the projectile (13) has left the barrel portion (15) of the housing (11), by when the gas in the chamber (21) will have reached the predetermined working pressure. <IMAGE>

Description

SPECIFICATION Load displacement device The present invention relates to a load displacement device and is particularly although not exclusively concerned with a projectile launching device for launching a projectile containing equipment which needs to be deployed at a location remote from the launching site.

Several types of projectile launching devices have been proposed which utilise gas under pressure for propulsion of the projectile from a launcher barrel. In one type of launcher there is provided a chamber for containing gas under pressure which communicates with the bore of the launcher barrel through one or more lateral apertures in the barrel which are closed off by the projectile itself when it is in a firing position in the barrel. The projectile is launched by initially advancing it to an advanced position in which the lateral aperture or apertures become uncovered, whereupon the pressurised gas flows from the chamber and acts on the base of the projectile to accelerate it along the barrel.For initially advancing the projectile in the barrel, it has been proposed to employ a plunger passing through the closed rear end of the barrel for engagement with the rear end of the projectile and a trigger mechanism for depressing the plunger to move the projectile to the advanced position. In another arrangement the projectile is advanced from its firing position to the advanced position under the action of gas under pressure fed to the rear end of the bore of the barrel and the arrangement is such that gas under pressure is first fed to the chamber from a pressurised gas supply under the control of a first manually operable valve to bring the gas in the chamber to a predetermined working pressure and the launcher fired by feeding gas under pressure from the pressurised gas supply to the rear end of the bore of the barrel by then opening a manually operable second valve.

While the use of pressurised gas for firing the launcher in the hitherto proposed arrangement can be considered as satisfactory for many uses of the launcher, two manual operations are required to charge the chamber to the working pressure and to fire the projectile and it has been found that there is a need for a launcher which requires only a single manual operation to charge the chamber and fire the projectile.

It is an object of the present invention to provide a projectile launching device which satisfies the above need.

According to the present invention there is provided a load displacement device for displacing a load under the action of fluid under pressure comprising a housing having a bore, a displaceable load arranged, in use of the device, in the bore of the housing, a chamber for containing fluid under pressure and communicating with the bore of the housing through one or more supply apertures in the bore of the housing, pressurised fluid supply means for supplying fluid under pressure to the chamber to bring the fluid in the chamber to a predetermined working pressure at which it is arranged to flow into the bore of the housing through the supply aperture or apertures to propel the load forwardly along the bore of the housing, and bleed means to bleed off fluid from the chamber to produce an auxiliary supply of fluid under pressure effective to cause the device to change from a first condition in which the flow of fluid from the chamber through the supply aperture or apertures to the bore of the housing is prevented to a second condition in which the flow of fluid from the chamber through the supply aperture or apertures to the bore of the housing is no longer prevented, the rate of supply of fluid from the supply means to the chamber and the rate of bleeding of fluid from the chamber by the bleed means to produce the auxiliary supply being such that the device is changed from its first condition to its second condition only after the fluid in the chamber has reached the predetermined working pressure.

In a preferred embodiment of the invention the bore of the housing is closed at its rear end, the supply aperture or apertures provide a communication between the chamber and the rear end of the bore of the housing, the load in the first condition of the device is arranged at a predetermined firing position in the bore of the housing in which it is effective to prevent the flow of fluid from the chamber through the supply aperture or apertures to the rear end of the bore of the housing, the arrangement being such that upon an advancement of the load from the firing position to an advanced position the load becomes no longer effective to prevent the flow of fluid from the chamber to the rear end of the bore of the housing, whereupon fluid under the predetermined working pressure in the chamber acts on the rear of the load to propel the load forwardly along the bore of the housing, and the bleed means is such as to apply the auxiliary supply of fluid under pressure to the rear end of the bore of the housing to advance the load from the firing position to the advanced position.

Preferably, the bleed means comprises a bleed duct extending through the housing to the rear end of the bore of the housing.

Furthermore, the chamber is preferably formed in the housing, with the bleed duct extending through the housing between the chamber and the rear end of the bore of the housing.

In an embodiment of the invention hereinafter to be described, the housing includes a removable bleed plug in which at least a portion of the bleed duct is formed to provide the predetermined rate of bleeding of fluid and the bleed plug is removably mounted in the housing and can be substituted by an alternative bleed plug having a bleed duct portion providing a predetermined different rate of bleeding of fluid.

Preferably, forward and rearward sealing elements are mounted in the load or the bore of the housing to prevent a flow of fluid from the chamber forwardly and rearwardly along the bore of the barrel in the firing position of the load.

Preferably, the pressurised fluid supply means comprises a cylinder containing gas under pressure and communicating with the chamber through valve means, and the cylinder is of such a capacity as to provide gas under pressure for a single firing of the device and is removably mounted on the housing.

Preferably, the bore of the housing is formed by a barrel portion, the chamber is formed as an annular space extending round the barrel portion and the supply aperture or apertures take the form of one or more lateral apertures in the barrel portion.

In an alternative embodiment of the invention there is provided a closure element movable between a closed position which it occupies in the first condition of the device and in which it closes the supply aperture or apertures and an open position which it occupies in the second condition of the device and in which it no longer closes the aperture or apertures and the auxiliary supply of fluid under pressure is applied to the closure element to move it from the closed position to the open position. The closure element may conveniently take the form of a sleeve coaxially mounted with respect to the bore of the housing and axially displaceable along the housing between the closed and open positions.

Embodiments of the invention will now be described by way of example with reference to the accompanying drawings in which: Fig. 1 is a schematic part cross-sectional side elevation of a projectile launching device according to a first embodiment of the invention, and Fig. 2 is a schematic cross-sectional side elevation of part of the projectile launching device shown in Fig. 1, modified according to a second embodiment of the invention.

Referring to Fig. 1 of the drawings, the projectile launching device shown comprises a launcher housing having a cylindrical main body portion 1 2 so extended as to support a projectile 13 in cylindrical coaxial forward and rearward inner barrel portions 14 and 1 5. As will be seen, the inner barrel portion 15 extends forwardly from the main body portion 1 2 and in coaxial relation therewith and the forward inner barrel portion 14 is carried by an annular end piece 1 6 formed on the forward end of a cylindrical outer barrel portion 1 7 which extends forwardly from the periphery of the main body portion 1 2 and in coaxial relation therewith.The inner barrel portions 14 and 1 5 together form an axial bore 18 for reception of the projectile 1 3 as shown, the axial bore 1 8 being provided with an open forward end 1 9 and being closed at its rear end by an end face 20 of the main body portion 12 of the housing 11. The forward and rearward inner barrel portions 14 and 1 5, the annular end piece 1 6 and the outer barrel portion 17, together with the main body portion 12, form an annular chamber 21 extending round the inner barrel portions 14 and 15 and communicating with the bore 1 8 through a lateral aperture 22 which extends throughout the circumference of the bore 18 and which is formed by the spacing of the inner barrel portions 14 and 15.

The projectile 1 3 comprises a cylindrical outer shell 23 which contains equipment required to be deployed at a position remote from the launching site. The shell 23 is fitted with forward and rearward ring seals 24 and 25 so positioned on the projectile shell 23 that in the firing position of the projectile shown in the drawing they form seals between the projectile shell and the inner barrel portions 14 and 1 5.

The main body portion 1 2 of the housing 11 is fitted with a manually operable control valve 26 having an inlet port 27 into which is screwed a pressurised gas supply cylinder 28 containing gas under high pressure and an outlet duct 29 extending through the main body portion 12 and opening into the chamber 21. The valve 26 is operated by manual depression of a release push button 30 outstanding from the main body portion 12 of the housing. A bleed duct 31 of predetermined length and bore extends through the main body portion 1 2 between the chamber 21 and the rear end of the bore 18.

The launcher housing 11, the projectile 1 3 and the cylinder 28 are supplied already assembled as shown in Fig. 1, the high pressure gas cylinder 28 having capacity adequate for a single charging and firing of the device.

When the launcher has been correctly positioned for firing the operator depresses the button 30 of the valve 26 which causes penetration of the nose cap of the cylinder 28, whereupon gas under high pressure is supplied to the chamber 21 to bring the gas in the chamber 21 to a predetermined working pressure. Gas under pressure in the chamber 21 is prevented from flowing through the aperture 22 by the presence of the projectile 1 3 and the two ring seals 24 and 25, the forward ring seal 24 preventing a flow of gas under pressure forwardly in the bore 1 8 and the ring seal 25 preventing a flow of gas under pressure rearwardly into the bore 18.

As the pressure of gas in the chamber 21 builds up to the working pressure, gas from the chamber 21 passes through the bleed duct 31 to provide an auxiliary supply of gas under pressure at the rear end of the bore 1 8 between the end face 20 of the main body portion 1 2 and the rear end of the projectile shell 23, which is formed with a cylindrical reentrant section 32 shown in broken line. The pressure of gas of the auxiliary supply gradually builds up until it becomes effective to advance the projectile 1 3 from the firing position shown in the drawing to an advanced position in which the ring seal 25 moves clear of the rear inner barrel portion 1 5 and into the region of the lateral aperture 22.As a consequence of this, gas under pressure in the chamber 21 flows direct to the rear end of the bore 1 8 through the lateral aperture 22 and acts on the rear end of the projectile to accelerate it forwardly along the bore 18 and discharge it at high velocity from the forward open end 1 9. The rate of supply of gas under pressure from the cylinder 28 to the chamber 21 and the rate of bleeding of gas under pressure from the chamber 21 through the bleed duct 31 to produce the auxiliary supply acting on the rear end of the projectile is arranged to be such that the projectile is advanced from its firing position to its advanced position only after the gas in the chamber 21 has reached a predetermined working pressure sufficient to propel the projectile 1 3 to its remote utilisation site.

When the projectile 1 3 has been fired, the operator returns the launcher for refitting with a new projectile and a replacement gas cylinder. In some situations however it may be advantageous to supply the operating personnel with the launcher housing 11, the projectile 1 3 and the gas cylinder 28 as component parts to be assembled at the launch site and to provide replacement gas cylinders and projectiles for use in subsequent firings. In this event, when the projectile 1 3 has been fired, the operator unscrews the cylinder 28 and discards it. A replacement cylinder is then fitted and a new projectile for launching pushed into the axial bore 1 8 up to the firing position.

It will be seen that the launcher housing 11 of the embodiment of the invention described with reference to Fig. 1 of the drawings is formed with a short bore 1 8 suitable for discharging projectiles containing equipment where the accuracy of firing is less important than the need to provide a compact launcher.

Where accuracy of firing is important, the barrel portions of the launcher housing 11 can be extended with the lateral aperture 22 disposed toward the rear end of the bore 1 8.

In the embodiment of the invention described with reference to Fig. 1 of the drawings, the bleed duct 31 is formed in the main body portion 1 2. Its length and bore diameter are so chosen that it will provide a time delay for movement of the projectile 1 3 from the firing position to the advanced position sufficient to charge the chamber 21 to a predetermined working pressure from a high pressure gas cylinder 28 of a predetermined capacity.

While the device as shown in Fig. 1 can be used satisfactorily where the mass of the projectile, its range when fired and the capacity and pressure of the gas cylinder used with the device are fixed, it will be apparent that it would be unsatisfactory where the device needs to be used in situations demanding the launching of projectiles of different masses, over different ranges or with gas cylinders of different capacities or pressures.

To overcome this drawback, the device described with reference to Fig. 1 is modified according to a second embodiment of the invention now to be described with reference to Fig. 2.

Referring to Fig. 2, the main body portion 1 2 of the housing 11 is drilled to form a blind bore 33 for reception of a removable bleed plug 34 having a shank portion 35 which fits in the bore 33 and a screw threaded portion 36 which is screwed into a counterbored screw-threaded portion of the bore 33.The shank portion 35 of the plug is formed with an annular channel 37 communicating with a duct 38 which is formed in the body portion 1 2 and which extends between the bore 33 and the chamber 21, a further annular duct 39 communicating with a further bore 40 which is also formed in the body portion 1 2 and which extends between the bore 33 and the end face 20 of the body portion 1 2 and a bleed duct 41 extending axially through the shank 35 and communicating at one end with the channel 37 and at the other end with the channel 39.

The launching device in accordance with the embodiment illustrated in Fig. 2 of the drawings is operated in the same manner as that of the device shown in Fig. 1, but has the advantage that it can be adapted for use in a variety of situations by providing alternative bleed plugs 34 having bleed ducts 41 of predetermined different bore diameters.

A launching device of the compact configuration shown in Fig. 1 or 2 of the drawings could for example be used for parachute ejection. The launching device when used for this purpose would be mounted ready for launching with the charged gas cylinder 28 in position and the projectile 1 3 at the firing position and the valve 26 operated by the parachutist during descent or automatically operated after a predetermined time delay or at a predetermined altitude.

The launching device according to the invention may of course be used for the firing of projectiles of any form and its use can be extended to the firing of offensive projectiles where the range and accuracy of firing is not of great importance.

It will be appreciated that in the embodi ment of the invention described with reference to Fig. 1 of the drawings, the projectile itself together with its ring seals 24 and 25 serve to prevent a flow of gas from the chamber 21 to the bore 18 until the projectile 1 3 is advanced from its firing position to the advanced position. In an alternative embodiment of the invention the lateral aperture 22 is closed by a sleeve coaxially mounted with respect to the bore 18 and axially displaceable between a closed position in which it closes off the lateral aperture 22 and an open position in which it is clear of the aperture 22 and the projectile 1 3 is placed at a firing position forward of the aperture 22.In this alternative embodiment of the invention, the bleed duct 31 is replaced by a bleed duct extending from the chamber 21 to the sleeve to produce an auxiliary supply of gas under pressure effective to move the sleeve from the closed position to its open position. The rate of supply of gas under pressure from the cylinder 28 to the chamber 21 and the rate of bleeding of gas under pressure from the chamber 21 to produce the auxiliary supply is then made such that the sleeve is moved from its closed position to its open position only after the gas in the chamber 21 has reached the predetermined working pressure.

In the embodiments of the invention hereinbefore described the device is preferably charged and fired by carbon dioxide under pressure. It will however be appreciated that other gases such as nitrogen and air could equally well be used.

The projectile launching device according to the invention can by virtue of its compact configuration and ease of operation conveniently be used in emergency situations. For example it could form part of equipment carried by commando units where the device would be used for grapnel and line throwing.

Claims (14)

1. A load displacement device for displacing a load under the action of fluid under pressure comprising a housing having a bore, a displaceable load arranged, in use of the device, in the bore of the housing, a chamber for containing fluid under pressure and communicating with the bore of the housing through one or more supply apertures in the bore of the housing, pressurised fluid supply means for supplying fluid under pressure to the chamber to bring the fluid in the chamber to a predetermined working pressure at which it is arranged to flow into the bore of the housing through the supply aperture or apertures to propel the load forwardly along the bore of the housing, and bleed means to bleed off fluid from the chamber to produce an auxiliary supply of fluid under pressure effective to cause the device to change from a first condition in which flow of fluid from the chamber through the supply aperture or apertures into the bore of the housing is prevented to a second condition in which the flow of fluid from the chamber through the supply aperture or apertures to the the bore of the housing is no longer prevented, the rate of supply of fluid from the supply means to the chamber and the rate of bleeding of fluid from the chamber by the bleed means to produce the auxiliary supply being such that the device is changed from its first condition to its second condition only after the fluid in the cham ber has reached the predetermined working pressure.

2. A device according to claim 1, wherein the bore of the housing is closed at its rear end, wherein the supply aperture or apertures provide a communication between the chamber and the rear end of the bore of the housing, wherein the load in the first condition of the device is arranged at a predetermined firing position in the bore of the housing in which it is effective to prevent the flow of fluid from the chamber through the supply aperture or apertures to the rear end of the bore of the housing, the arrangement being such that upon an advancement of the load from the firing position to an advanced position the load becomes no longer effective to prevent the flow of fluid from the chamber to the rear end of the bore of the housing, whereupon fluid under the predetermined working pressure in the chamber acts on the rear of the load to propel the load forwardly along the bore of the housing, and wherein the bleed means is such as to apply the auxiliary supply of fluid under pressure to the rear end of the bore of the housing to advance the load from the firing position to the advanced position.

3. A device according to claim 2, wherein the bleed means comprises a bleed duct extending through the housing to the rear end of the bore of the housing.

4. A device according to claim 3, wherein the chamber is formed in the housing.

5. A device according to claim 4, wherein the bleed duct extends through the housing between the chamber and the rear end of the bore of the housing.

6. A device according to claim 5, wherein the housing includes a removable bleed plug in which at least a portion of the bleed duct is formed to provide the predetermined rate of bleeding of fluid and wherein the bleed plug is removably mounted in the housing and can be substituted by an alternative bleed plug having a bleed duct portion providing a predetermined different rate of bleeding of fluid.

7. A device according to any of claims 1 to 6, comprising forward and rearward sealing elements mounted in the load or the bore of the housing to prevent a flow of fluid from the chamber forwardly and rearwardly along the bore of the barrel in the firing position of the load.

8. A device according to claim 7, wherein the sealing elements are mounted in the load.

9. A device according to any of claims 1 to 8, wherein the pressurised fluid supply means comprises a cylinder containing gas under pressure and communicating with the chamber through valve means, and wherein the cylinder is of such a capacity as to provide gas under pressure for a single firing of the device and is removably mounted on the housing.

10. A device according to any of claims 1 to 9, wherein the bore of the housing is formed by a barrel portion and the chamber is formed as an annular space extending round the barrel portion.

11. A device according to claim 10, wherein the supply aperture or apertures take the form of one or more lateral apertures in the barrel portion.

1 2. A device according to claim 11, wherein the lateral aperture extends throughout the circumference of the barrel portion of the housing.

1 3. A device according to claim 1, comprising a closure element movable between a closed position which it occupies in the first condition of the device and in which it closes the supply aperture or apertures and an open position which it occupies in the second condition of the device and in which it no longer closes the aperture or apertures and wherein the auxiliary supply of fluid under pressure is applied to the closure element to move it from the closed position to the open position.

14. A device according to claim 13, wherein the closure element comprises a sleeve coaxially mounted with respect to the bore of the housing and axially displaceable along the housing between the closed and open positions.

1 5. A projectile launching device substantially as hereinbefore described with reference to Fig. 1 or 2 of the accompanying drawings.