FIELD OF THE INVENTION It is at present common practice for sub-callibre projectiles fired from a broad range of guns, grenade- launchers, artillery and the like to be provided with a full-calibre sabot facilitating such firing. The sabot acts as a carrier for the projectile and serves to transmit the firing forces provided by the propellant to the projectile.

A discarding sabot is traditionally designed to break up and discard from the projectile it carries after exit ^' from the barrel or muzzle from which it was fired. This then leaves the projectile free to travel towards and contact its target.

The discarding of the sabot is at present achieved through a number of means. A sabot design that has an air resistance whereby the air effectively forces the sabot of the projectile. Such design is commonly referred to as

"open-ended". Aerodynamic heating that causes the loss of a nose portion of the sabot due to a predetermined thermal failure threshold thereby allowing air to then force the

sabot off. The use of lines of weakness in the sabot essentially forming break grooves running the length of the sabot facilitating the breaking up and discarding of the sabot. Shaping of the sabot that imparts a spin therein such that the centrifugal force generated aids in discarding the sabot.

It is not uncommon for a combination of these and other features to be utilized in the discarding of a sabot. The typical discarding sabot presents a problem when being used in a situation such as firing in ranks. As the sabot discards fragments thereof can hit and damage "friendly" personnel or equipment due to a haphazard discarding pattern. This situation can be extended to tanks, artillery and the like. In many instances a discarding sabot may be required to have a highly robust construction. Particularly in the case of an anti-riot round being dropped while being loaded into a launcher by nervous or inexperienced personnelor possibly during nocturnal deployment. Also, damage should be avoided during automatic loading into automatic weaponry such as automatic grenade launchers.

When deployed "in the field" water, mud, dust and the like may foul the sabot. This may cause sabot failure when the sabot and projectile are fired or launched. The open-ended sabot design commonly relies on an unaerodynamic shape to discard the sabot as stated perviously. This may to some extent limit the accuracy and/or efficacy of the projectile in such a case.

SUMMARY OF THE INVENTION The present invention provides a discarding sabot that attempts to overcome those problems associated with the prior art. In accordance with one aspect of the present invention there is provided a discarding sabot designed to enable the launching or firing of a projectile, the sabot being in contact with and enclosing at least a portion of the projectile or payload, the sabot having a sealed frontal nose section and a cavity located therebehind, the nose section having at least a portion thereof that is specifically tensioned against aerodynamic forces encountered after firing or launching such that when air pressure on the tensioned portion overcomes the specific tensioning air pressure enters the cavity thereby promoting the discarding of the sabot.

Preferably, the nose section comprises a movable portion therein such that the sealing means is held in position by a tensioning means. After launch or firing the air pressure acts on the movable portion of the nose section. When the air pressure on the movable portion overcomes the tensioning means, the movable portion is forced within the nose section allowing air pressure into the cavity thereby promoting the discarding of the sabot. Preferably, the discarding sabot further comprises a number of lines of weakness running the length of the sabot further facilitating the discarding of the sabot once air pressure has overcome the tensioning means.

The cavity behind the nose section may be either the cavity in which the projectile or payload is located or may be an additional and isolated cavity provided forward of the projectile or payload. The projectile may comprise any items or material that is transportable by way of firing, launching or dropping. Such items and materials include high explosive rounds (HEAT rounds, HESH rounds and HEAP rounds for example) whether they be. ant-tank, anti-artillery or anti-personnel rounds,'liquids such as tear gas and dyes, military fuses, electronic equipment including circuit boards and cameras, and anti-riot rounds. Such anti-riot rounds may comprise either components to partially or totally temporally physically incapacitate (including plastic or rubber fragments ) and identify (paint balls and the like) or may comprise a combination of both.

BRIEF DESCRIPTION OF THE DRAWINGS The present invention will now be described, by way of example, with reference to the accompanying drawings in which;

Figure 1 is a perspective view of an anti-riot round embodying a discarding sabot in accordance with the present invention;

Figure 2 is an exploded perspective view of the anti-riot round of Figure 1 shown with the cartridge case removed; Figure 3 is a cross-sectional view of the anti-riot round of Figure 2 having the protective cap raised; Figure 4 is a side view of a means for removal of an

anti-riot round from a launcher thereof shown being applied to the anti-riot round of Figure 1;

Figure 5 is a perspective view of the removal means in use on the anti-riot round of Figure 1; Figure 6 is an exploded view of an anti-tank round embodying a discarding sabot in accordance with the present invention;

Figure 7 is a cross-sectional view of the anti-tank round of Figure 6; Figure 8 is a perspective view of the anti-tank round of Figure 6 showing the sabot discarding; and Figure 9 is a cross-section view of the forward tip of a discarding sabot in which there is provided an alternative tensioning means. DESCRIPTION OF THE INVENTION

In Figure 1 there is shown an anti-riot round 10 comprising a cartridge case 12, a protective cap 14 and a discarding sabot 16.

The cartridge case 12 further comprises a rim 18 and a primer system 20.

In Figure 2 and 3 there is shown the anti-riot round 10 having the cartridge case 12 removed. The sabot 16 has four substantially identical segments 22. Each segment 22 comprises an outer wall 24, a pusher plate 26 and a payload support 28. Further each segment 22 has a nose portion 30 and a cavity wall 32. The nose portions 30 have an upstanding portion 34 provided at their forward most point. One of the segments 22 is provided with a seat 36 on the

cavity wall 32, best seen in Figure 2.

The four segments 22 when joined form a forward cavity 38 and a payload cavity 40, as shown in Figure 3. The forward cavity 38 is sealed and separate from the payload cavity 40.

The forward cavity 38 houses a tensioning means 42 having a first end 44 and a second end 46. The first end 44 is received in a recess 48 in a sealing means 50. The second end 46 is received in the seat 36 on the cavity wall 32. The sealing means 50 has a forward surface 52 substantially cone shaped to conform to an inner face 54 of the nose portion 30. There is provided a raised central portion 56 having a concave forward surface 58. The nose portions 30 of the segments 22 when joined further define a forward aperture 60. The central portion 56 projects into the aperture 60. The upstanding portion 34 surrounds the aperture 60.

A payload 66 is located in the payload cavity 40. In this case the payload 66 comprises a solid component 68 and a frangible component 70.

The nose portions 30 have provided in a forward surface 72 recesses 74, see Figure 4 and 5.

As shown in Figure 3, the protective cap 14 fits over the forward end of the sabot 16 to protect the aperture 60. The segments 22 of the sabot 16 may, for example be held together by press fit studs (not shown) or may be joined initially by lines of weakness in the outer wall 24. In Figures 4 and 5 there is shown a removal means 76

comprising a handle 78 and arms 80. A gripping means 82 is provided at a first end 86 of each arm 80. A second end 84 of each arm is joined to the handle 78. A movable clip 88 is provided around the arms 80. The forward surface 72 of the nose portion 30 is visable in a barrel 92 of a anti-riot round launcher in the loaded position.

Figure 5 shows a user 94 removing the anti-riot round 10 from the barrel 92. In Figures 6 and 7 there is shown an anti-tank round 100 comprising a discarding sabot 102 in three segments 104 and a payload 106.

The segments 104 are substantially identical. Each segment 104 comprises an outer wall 108, a pusher plate 110, and a payload support 112.

Further, each segment 104 has a nose portion 114 and a cavity wall 116.

The outer wall 108 has a number of driving bands 118 located thereon. One of the segments 104 is provided with a seat 120 on the cavity wall 116, best seen in Figure 6.

The three segments 104 when joined from a forward cavity 122 and a payload cavity 124, as shown in Figure 7. The forward cavity 122 is sealed and separate from the payload cavity 124. The payload cavity 124 is shaped to hold a specific payload 106. This comprises a ribbed surface 126 to grip a complimentary surface 128 on the payload 106. The forward cavity 122 is of substantially the same

- o — construction as that of the anti-riot round 10 and like numerals denote like parts. There is provided therein the tensioning means 42 having its first end 44 received in the recess 48 in the sealing means 50. The second end 46 is received in the seat 36 on the cavity wall 116.

The forward surface 52 of the sealing means 50 is again conformed to the inner face 54 of the nose portion 114. The raised central portion 56 again has the concave forward surface 58. The forward aperture 60 is defined by the nose portions 114 of the segments 104. The central portion 56 projects into the aperture 60. An O-ring 130 is provided in the aperture 60 to form a seal between the aperture 60 and the central portion 56. In Figure 8 there is shown the discarding sabot 102 breaking away from the payload 106. The segments 104 may be joined and defined by lines of weakness in the sabot

102.

In Figure 9 there is shown an alternative to the tensioning means 42 of the discarding sabots 16 and 102 and like numerals denote like parts. The sealing means 50 has an aperture 150 provided therein running from the concave surface 58 through its centre. The aperture 150 has a serrated inner surface 152. A post 154 projects forwardly from the seat 36, 120 to terminate in the forward aperture 60. The post 154 has a serrated outer surface 156.

The sealing means 50 is engaged on the post 154 such that

the forward surface 52 thereof engages the inner face 54 of the nose portion 72, 114. The serrated surfaces 152 and 156 engage and prevent the sealing means 50 moving freely over the post 154. In use, the anti-riot round 10 may be loaded by a number of mechanisms into a purpose made launcher or similar (not shown) by a user (not shown) . It will be required that the cap 14 be removed before loading as it makes the round 10 too large to load otherwise. Projection of the anti-riot round 10 may be effected by a number of means reasonably envisaged by the skilled addressee.

After discharge of the anti-riot round 10 air pressure will build up against the concave forward surface 58. The tensioning means 42 is set to resist a predetermined pressure. Once this pressure is exceeded the tensioning means 42 gives way such that the seal of the sealing means 50 against the inner face 54 and the raised central portion 56 against the forward aperture 60 are broken. The sealing means 50 then recedes into the forward cavity 38. This allows air pressure into the forward cavity 38 which effects the breakage of the sabot 16 into the portions 22. Once the portions 22 have been discarded the payload 66 continues on its trajectory toward a target (not shown) in the known manner. If the payload 66 comprises a solid component 68 the target may be partially or totally temporally physically incapacitated. If the payload additionally or alternatively comprises a frangible

component identification of a target may also be achieved. It is envisaged that such identification may occur by way of odourous substances, dyes, lourescent dyes, gases, radioactive substances and the like. The payload 66 may be provided with one or more stabilizing means to facilitate accurate trajectory once the sabot 16 has been discarded.

The cap 14 and the upstanding portions 34 serve to protect the sealing means 50 and the tensioning means 42 from Q shocks, possibly caused in part by dropping of the anti-riot round 10. Such shocks could contribute ordinarily to malfunction in the anti-riot round 10. An anti-riot round 10 that has been loaded into a launcher barrel 92 may be removed using removal means 76, as is best 5 seen in Figures 4 and 5. The gripping means 82 engage the recesses 74 upon sliding of the clip 88 along the arms 80 towards the second end 84 thereof. A user 94 girpping the handle 78 may then withdraw the anti-riot round 10 from the barrel 92 as shown in Figure 5. 0 The anti-tank round 100 may also be loaded by a number of mechanisms into/onto a launching or firing device, typically, the anti-tank round 100 is fired from a tank, artillery or launcher in a manner reasonably envisaged by the skilled addressee. 5 After discharge, the function of the sabot 102 is substantially the same as that of the sabot 16. Air pressure is built up against the concave forward surface 58. Again, the tensioning means 42 is set to resist a

predetermined pressure. Once the air pressure overcomes the tensioning means 42 the air pressure enters the forward cavity 122.

Thereafter, the air pressure in the forward cavity 122 commences the breakage of the sabot 102 along the predetermined lines of weakness that device the sabot 102 into portions 104.

As shown in Figure 8, the portions 104 are discarded and the payload 106 continues on this trajectory toward a target (not shown) in known manner.

The tensioning means 42 is replaced in Figure 9 by the post 154. The method of use is substantially the same however. After the discharge of the round 10 or 100 air pressure again builds up against the concave forward surface 58. This pressure is resisted by the engagement of the post 154 and the sealing means 50 by way of the serrated surfaces 152 and 156.

The serrated surfaces 152 and 156 are formed such that they will give way once a certain magnitude of pressure is reached. This then causes the braking of the seal between the sealing means 50 and the inner face 54 and between the raised central portion 56 and the O-ring 130 of the forward aperture 60. The discarding of the sabot 16 or 102 then occurs as previously described. It is envisaged that the tensioning means may take a number of forms and it is to be understood that those described above are by way of example only. The tensioning means allows the predetermination of the

distance away from the point of discharge that a discarding sabot 16 or 102 will discard.

The payloads carried away by a discarding sabot of the present invention are to be understood to be of the broadest nature including liquids, military fuses, electronic devices and equipment and cameras. Also, most forms of munitions may be carried by the discarding sabot of the present invention. It is envisaged that the tensioning means of the present invention could be activated electronically or by some other mean ^' s of communication between a controlling body and the sabot to increase the accuracy of the point of discarding the sabot. For example, this could be utilised in cases where the distance required before the discarding of the sabot is physically impossible for the tensioning means employed to withstand. A signal may be transmitted to the sabot after a required distance has been travelled only after which the tensioning means operates as described previously. Before this point it was prevented from doing so either mechanically or electronically.

The discarding sabot of the present invention provides a further advantage when used with automatic ammunition. The present discarding sabot encloses the forward end of the payload. However, prior art sabots often form a shoulder behind the point of the payload to catch air pressure leaving the payload to be damaged during introduction to the cartridge chamber. Further, despite enclosing the forward end of the payload the present discarding sabot is

still discardable by way of air pressure and optionally other aerodynamic pressures such as spinning induced by the sabot and aerodynamic heating.

This construction also provides advantages in use in the field allowing rough handling of the rounds containing the sabot. The seal provided at the forward end of the discarding sabot prevents water, mud or dust fouling the sabot and causing sabot failure or malfunction.

It is further envisaged that the point at which the tensioning means comes into effect during the flight of the sabot may be triggered by aerodynamic heating.

It is also envisaged that the forward cavity 38 or 124 may not be totally isolated from the payload cavity 40 or 124. Such an arrangement would still require a seat for the tensioning means.

However, the introduction of air pressure into the payload cavity 40 or 124 could effectively cause breakage of the sabot 16 or 102 into portions 22 or 104.

The discarding sabot of the present invention may be formed of plastics materials, metallic alloys or a combination thereof such as would be evident to a skilled addressee. The tensioning means may take the form of a flexibly resilient member, for example a spring or rubberised component, a plasticised component or a form of electronic activation.

Modifications and variations as would be apparent to a skilled addressee are deemed within the scope of the present invention.