GB2105447A - Projectile launching device - Google Patents

Abstract

A device for launching a projectile for line-throwing or one containing equipment (eg a liferaft) comprises a barrel (12, 14, 19) recessed to form between it and the projectile (29) a chamber (23) for containing compressed air. A forward resilient seal (32) is mounted in the projectile or the barrel, while the rear of the projectile (29) is provided with a resilient skirt (33) engaging a boss (22) extending forwardly from the rear of the barrel. Compressed air supplied to the chamber (23) presses the skirt (33) against the boss (22) to produce a frictional resistance sufficient to hold the projectile (29) in the firing position. The projectile (29) is advanced from the firing position under the action of a secondary supply of compressed air applied to the rear of the projectile and when the skirt (33) moves clear of the boss (22) the compressed air in the chamber (23) acts on the rear of the projectile to propel it forwardly along the barrel. <IMAGE>

Description

SPECIFICATION Projectile launching device Projectile launching devices have been proposed for deploying lines between remote points such as between a ship and a mooring point on shore and also for deploying equipment at a remote point for which purpose the equipment is loaded within the projectile which is then launched and the equipment removed from the projectile or automatically released from it on arrival of the projectile at the remote point.

Projectile launching devices as above described have hitherto been of the kind in which an explosive charge is used for propulsion of the projectile from a launch tube. The use of an explosive charge for propulsion of the projectile, however, calls for special precautions in the use and construction of the device and in the storage of the charges.

It is an object of the present invention to provide a projectile launching device in which the projectile is launched under the action of air or gas under pressure so that the disadvantages found in lauching devices using explosive charges can be avoided.

According to the present invention, there is provided a projectile launching device for launching a projectile under the action of air or gas under pressure comprising a barrel having an axial bore, and a projectile arranged, in use of the device, at a firing position in the bore of the barrel, wherein the cross-section of the bore of the barrel at the firing position of the projectile and the cross-section of the projectile is such as in the firing position of the projectile to provide between the barrel and the projectile a chamber for containing air or gas under pressure, wherein forward sealing means is mounted in or forms part of the projectile or the barrel and is arranged to prevent or control the flow of air or gas from the chamber forwardly along the bore of the barrel, wherein the rear of the projectile is provided with a resilient rearwardly extending skirt portion so arranged in the firing position of the projectile as to engage over an axial boss portion extending forwardly from a rear end of the barrel, wherein projectile advancing means is provided for advancing the projectile in the barrel from the firing position to an advance position in which the skirt portion of the projectile moves clear of the boss portion, and wherein the arrangement is such that when air or gas is supplied to the chamber under pressure it acts upon the skirt portion to press it against the boss portion to prevent or control the flow of air or gas from the chamber around the skirt portion to the rear of the projectile within the skirt portion and to produce a frictional resistance sufficient to hold the projectile in the firing position against any tendency for it to move forward except under the action of the projectile advancing means and when the skirt portion moves clear of the boss portion under the action of the projectile advancing means the air or gas under pressure in the chamber thereupon acts on the whole of the cross-sectional area of the rear of the projectile to propel the projectile forwardly along the bore of the barrel and launch it from the forward end of the barrel.

The projectile advancing means preferably comprises air or gas supply means supplying to the bore of the barrel at an opening in the forward end of the boss portion of the barrel air or gas under pressure to advance the projectile from the firing position to the advance position. The air or gas supply means preferably comprises valve means connected to supply air or gas under pressure from the chamber.

The chamber in an embodiment of the invention hereinafter to be described is formed by a circumferential recess in the bore of the barrel and is provided with an inlet for connection to a source of gas under pressure, which may take the form of a high pressure air or gas cylinder and valve means for controlling the supply of high pressure air or gas from the cylinder to the chamber.

The boss portion of the barrel in the embodiment hereinafter to be described forms a frusto cone, the cross-section of which reduces in a direction toward the forward end of the barrel, and the internal surface of the skirt portion conforms to the frusto-conical shape of the boss portion. The boss portion is preferably formed in a recess in the rear end of the barrel to provide an annular channel in which the skirt portion engages.

The forward sealing means in the embodimnent of the invention hereinafter to be described comprises a forward resilient sealing element mounted in or forming part of the projectile and arranged in the firing position of the projectile to engage the bore of the barrel at a position forward of the chamber. For some purposes it may however be convenient to provide as the forward sealing means a forward sealing element mounted in or forming part of the barrel of the device.

The chamber may effectively be enlarged by providing a projectile of reduced cross-section between the forward sealing means and the skirt portion as hereinafter to be described with reference to the drawings.

While the projectile may be of solid form for example for deploying a line required to extend from the launch site to a remote point it is in the embodiment of the invention hereinafter to be described so constructed as to contain equipment, such as a liferaft, required at a location remote from the site for deployment at the remote location.

Two embodiments of the invention will now be described by way of example with reference to the accompanying drawing in which: Fig. 1 is a schematic cross-sectional side elevation of a projectile launching device according to a first embodiment of the invention, Fig. 2 is an end view of the device shown in Fig.

1, Fig. 3 is a further end view of the device shown in Fig. 1, Fig. 4 is a schematic diagram of a high pressure air or gas supply system for the device shown in Fig. 1 and Fig. 5 is a cross-sectional side elevation part of a projectile launching device according to a second embodiment of the invention.

Referring first to Figs. 1 to 3, a launch tube 11 comprises a forward portion 12 provided with an axial bore 13 and secured at its rear end to a main body portion 14 by a retaining ring 1 5 held by headed screws 1 6. The body portion 14 is formed at its foremost end with an axial bore 1 7 corresponding to that of the bore 1 3 of the forward portion 12 and is formed rearwardly of the bore 17 with a counter-bore 18, into the rearmost end of which is fitted a plug 1 9 held in place by headed screws 20 and provided with an O-ring seal 21 forming a gas-tight seal between the plug 19 and the body portion 14.The plug 19 is formed with frusto-conical boss 22 which extends forwardly from the base of a cylindrical recess which provides with the boss 22 an annular channel 24, the inner wall of which is formed by the frusto-conical wall of the boss and the outer wall of which is formed by the cylindrical wall of the recess which is dimensioned to conform to the bore 1 7 of the body portion 14. The main body portion 1 4 of the launch tube is formed with a supply port 27 for connection to a supply of air or gas under pressure and the plug 1 9 is likewise provided with a supply port 28 for connection to be pressurised air or gas supply as hereinafter to be described.

In use of the launch tube a projectile 29 is muzzle ioaded into the tube and takes up a firing position as illustrated in Fig. 1. The projectile 29 is formed with a nose portion 30, a constant diameter body portion 31 and a skirt portion 33 and is so dimensioned as to form a sliding fit within the bore 13 of the forward portion 12.The projectile 29 carries a forward resilient circumferential seal 32 which is mounted in a circumferential slot in the projectile body portion 31 and which is arranged to bear in a gas-tight manner against the bore 17 of the body portion 14 of the launch tube.

The skirt portion 33 of the projectile 29 is so dimensioned as, in the firing position of the projectile 29 as shown in Fig. 1, to engage in the annular channel 24 with the rear end of the projectile within the skirt portion 33 engaging the end face of the boss 22. The projectile 29 or at least that portion which forms the skirt portion 33 is made from a resilient material so that the skirt portion can be caused to press firmly and in gas tight manner against the frusto-conical wall of the boss 22.

Referring now to Fig. 4, the port 27 of the body portion 14 of the launch tube 11 is connected to a high pressure air or gas inflation cylinder 34 through a manually operable control valve 35 spring-loaded to its off position and movable to its open position by depression of a push button 36.

The supply port 28 is connected to the supply line 37 through a further manually operable control valve 38 spring-loaded to its off position and movable to its open position by depression of a push button 39. A pressure release valve 40 is connected to the line 37 to limit the air pressure on line 37 to a predetermined maximum level.

In operation, the launch tube 11 assembled as shown in Fig. 1 is mounted at a launch site on a mounting which enables the launch tube to be set for launching a projectile in the required direction and with the required trajectory. The projectile 29 carrying equipment required at a remote location is muzzle-loaded into the forward portion 12 to take up under its own weight the firing position illustrated in Fig. 1 in which the skirt portion 33 of the projectile engages in the channel 24 over the boss 22 in the plug 19. With the projectile 29 so positioned the push button 36 of the control valve 35 is depressed to supply air under high pressure along the line 37 and via the supply port 27 to the chamber 23.

The forward seal 32 carried by the projectile 29 prevents the flow of air from the chamber forwardly along the bore of the body portion 14 and the forward portion 12 of the launcher tube.

The flexible skirt portion 33 is subjected to pressure from the air under pressure in the chamber 23 causing it to deflect radially inwardly and to press firmly against the frusto-conical wall of the boss 22, thereby forming a gas-tight seal preventing the flow of air from the chamber 23 to the rear of the projectile within the skirt portion 33. Furthermore, the pressure contact between the skirt portion 33 and the frusto-conical wall of the boss 22 produces a frictional resistance to movement of the projectile 29 from the firing position and the arrangement is made such that the frictional resistance is sufficient to hold the projectile 29 in the firing position against any tendency for it to move forward under the action of air under pressure in the chamber 23.

When the chamber 23 is fully charged with air under pressure from the cylinder 34 the push button 39 of the valve 38 is then depressed to connect the supply line 37 to the port 28 in the rear end of the plug 19. The air under pressure supplied to the port 28 exerts a thrust on the rear end of the projectile 29 within the skirt portion 33, urging the projectile 29 forward in the launch tube against the frictional resistance produced by contact of the skirt portion 33 with the boss 22.

As a result, the projectile 29 advances from its firing position to a position in which the skirt portion 33 no longer prevents the pressurised air in the chamber 23 from passing to the rear of the projectile within the skirt portion 33. The projectile 29 is then rapidly accelerated from the advance position under the full thrust of the pressurised air in the chamber 23 acting on the whole of the rear of the projectile and launched from the forward end of the forward portion 12 of the launch tube 11.

It will be appreciated that the chamber 23 may be of shapes other than that illustrated in Fig. 1 and may effectively be enlarged by arranging for the projectile 29 to be reduced cross-section between the forward seal 32 and the skirt portion 33. As shown in Fig. 5 a projectile 29' is provided for use with the launcher tube 11 of the embodiment described with reference to Figs. 1 to 4 and includes a waisted portion 41 which in the firing position of the projectile as shown in Fig. 5 effectively enlarges the chamber 23 formed in the body portion 14 of the launcher tube. The mode of operation of the launcher tube 11 with the projectile 29' is nevertheless identical to that of the embodiment described with reference to Figs.

1 to 4, with the added advantage of the provision of a chamber 23 which has been enlarged without the need for increasing the dimensions of the launch tube 11.

In the embodiments of the invention described with reference to the drawings, the seal 32 is an element mounted on the projectile 29. It will however be appreciated that the seal may itself form part of the projectile or it may alternatively be mounted in the body portion 14 of the launch tube 11.

While the projectile 29 in the embodiments hereinbefore described with reference to the drawings is advanced from its firing position to the advance position under the control of air under pressure supplied to the port 28, other advancing means may if desired by employed. Furthermore, while in the embodiments hereinbefore described with launch tube 11 is constructed for muzzleloading of the projectile, the plug 19 may alternatively be made readily removable to provide for breech-loading of the projectile.

Claims (12)

1. A projectile launching device for launching a projectile under the action of air or gas under pressure comprising a barrel having an axial bore, and projectile arranged, in use of the device, at a firing position in the bore of the barrel, wherein the cross-section of the bore of the barrel at the firing position of the projectile and the cross-section of the projectile is such as in the firing position of the projectile to provide between the barrel and the projectile a chamber for containing air or gas under pressure, wherein forward sealing means is mounted in or forms part of the projectile or the barrel and is arranged to prevent or control the flow of air or gas from the chamber forwardly along the bore of the barrel, wherein the rear of the projectile is provided with a resilient rearwardly extending skirt portion so arranged in the firing position of the projectile as to engage over an axial boss portion extending forwardly from a rear end of the barrel, wherein projectile advancing means is provided for advancing the projectile in the barrel from the firing position to an advance position in which the skirt portion of the projectile moves clear of the boss portion, and wherein the arrangement is such that when air or gas is supplied to the chamber under pressure it acts upon the skirt portion to press it against the boss portion to prevent or control the flow of air or gas from the chamber around the skirt portion to the rear of the projectile within the skirt portion and to produce a frictional resistance sufficient to hold the projectile in the firing position against any tendency for it to move forward except under the action of the projectile advancing means and when the skirt portion moves clear of the boss portion under the action of the projectile advancing means the air or gas under pressure in the chamber thereupon acts on the whole of the cross-sectional area of the rear of the projectile to propel the projectile forwardly along the bore of the barrel and launch it from the forward end of the barrel.

2. A device according to claim 1 , wherein the projectile advancing means comprises air or gas supply means supplying to the bore of the barrel at an opening in the forward end of the boss portion of the barrel air or gas under pressure to advance the projectile from the firing position to the advance position.

3. A device according to claim 2, wherein the air or gas supply means comprises valve means connected to supply air or gas under pressure from the chamber.

4. A device according to any of claims 1 to 3, wherein the chamber is formed by a circumferential recess in the bore of the barrel.

5. A device according to any of claims 1 to 4, wherein the chamber is provided with a an inlet for connection to a source of air or gas under pressure.

6. A device according to claim 5, wherein the source of air or gas under pressure comprises a high pressure air or gas cylinder and valve means for controlling the supply of high pressure air or gas from the cylinder to the chamber.

7. A device according to any of claims 1 to 6, wherein the boss portion of the barrel forms a frusto cone, the cross-section of which reduces in a direction toward the forward end of the barrel, and wherein the internal surface of the skirt portion conforms to the frusto-conical shape of the boss portion.

8. A device according to claim 7, wherein the boss portion is formed in a recess in the rear end of the barrel to provide an annular channel in which the skirt portion engages.

9. A device according to any of claims 1 to 8, wherein the forward sealing means comprises a forward resilient sealing element mounted in or forming part of the projectile and arranged in the firing position of the projectile to engage the bore of the barrel art a position forward of the chamber.

10. A device according to any of claims 1 to 9, wherein the chamber is effectively enlarged by providing a projectile of reduced cross-section between the forward sealing means and the skirt portion.

11. A device according to any of claims 1 to 10, wherein the projectile is constructed to contain equipment required at a Icoation which is remote from the site of the device and to which the projectile is directed when launched.

12. A projectile launching device substantially as hereinbefore described with reference to Figs. 1 to 4 or 5 of the accompanying drawings.