Abstract
A projectile for piercing a casing of a mine containing an explosive material. The projectile includes a projectile body having a nose portion and a tail portion and a longitudinal axis, a switch, and electrodes separated such that in use an electrical discharge can flow between them through an explosive material contained within a mine, or to initiate an energetic material provided between the electrodes to detonate an explosive material contained within a mine. Also provided is a method of mine disposal.
Claims
1. A projectile for piercing a casing of a mine containing an explosive material; the projectile comprising a projectile body having a nose portion and a tail portion wherein a longitudinal axis extends between the nose portion and the tail portion, the projectile body comprising a switch, a first electrode, and a second electrode; wherein the switch is configured to control a closure of a circuit connecting the first electrode and the second electrode to a source of electrical energy; and wherein the first electrode and the second electrode are separated by a separation distance such that in use an electrical discharge can flow between the first electrode and the second electrode, either through an explosive material contained within a mine, or through a material comprised between the electrodes or which is introduced between the electrodes in use, so as to cause the material to release energy so as to detonate an explosive material contained within a mine.
2. The projectile of claim 1 wherein the first electrode and the second electrode are separated by a separation distance such that in use an electrical discharge can flow between the first electrode and the second electrode through an explosive material contained within a mine.
3. The projectile of claim 1 comprising an energetic material comprised between the electrodes, wherein the first electrode and the second electrode are separated by a separation distance such that in use an electrical discharge can flow between the first electrode and the second electrode to initiate the material comprised between the electrodes.
4. The projectile of claim 3 wherein the nose portion is provided with a water ingress path arranged such that in use underwater, and wherein water can ingress to a location between the first and second electrodes, such that in use an electrical discharge can flow between the first electrode and the second electrode, through the water between the electrodes, to initiate the energetic material, to detonate an explosive material contained within a mine.
5. The projectile of claim 1 wherein the nose portion comprises whole or part of one or both of the first electrode and the second electrode.
6. The projectile of claim 1 wherein the first electrode and the second electrode are coaxially arranged about the longitudinal axis.
7. The projectile of claim 1 wherein the first electrode and the second electrode are separated along the longitudinal axis of the projectile by the separation distance.
8. The projectile of claim 1 wherein the nose portion comprises a detachable casing.
9. The projectile of claim 8 wherein the detachable casing is arranged to be detachable responsive to an impact between the projectile and a mine casing.
10. The projectile of claim 1 further comprising a retaining means for retaining the projectile partially within the casing of a mine.
11. The projectile of claim 10 wherein the retaining means comprises a flange projecting from the projectile body.
12. The projectile of claim 1, wherein the switch comprises a sensor configured to sense the piercing of a mine casing by the projectile.
13. The projectile of claim 12 wherein the switch comprises a first switch element and a second switch element, wherein the first switch element and the second switch element are separated along the longitudinal axis by a switch distance, and wherein the switch is compressible along the longitudinal axis such that in use impact of the projectile body with a mine casing causes relative movement between the first switch element and the second switch element such that the switch distance is reduced causing the switch to be triggered.
14. The projectile of claim 1 wherein the projectile further comprises a source of electrical energy.
15. The projectile of claim 14 wherein the source of electrical energy is integral to the projectile body.
16. The projectile of claim 15 wherein the source of electrical energy comprises a piezoelectric material.
17. The projectile of claim 15 wherein the source of electrical energy comprises a capacitor.
18. The projectile of claim 15 wherein energy source is arranged to supply between 1,000 to 30,000 volts per mm across the separation distance between the electrodes.
19. The projectile of claim 1 wherein the separation distance between the electrodes is in a range of 0.1 mm to 5 mm.
20. The projectile of claim 1, wherein the tail portion has a larger cross section than the nose portion with respect to the longitudinal axis, being at least double that of the nose portion.
21. A method of mine disposal, the method comprising the steps of: i. providing a projectile according to claim 1; ii. launching the projectile towards a mine; iii. piercing the casing of the mine with the projectile; and iv. applying a voltage between the first electrode and the second electrode of the projectile so as to cause an electrical discharge to flow between the first electrode and the second electrode either through an explosive material contained within a mine, or through a material comprised between the electrodes or which is introduced between the electrodes in use, so as to cause the material to release energy so as to detonate an explosive material contained within a mine.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
(1) The invention will now be described, purely by way of example, with reference to the accompanying drawings, in which;
(2) FIG. 1a shows a side elevation cross sectional illustration of a first embodiment of a projectile according to a first aspect of the invention;
(3) FIG. 1b shows a side elevation illustration of a first embodiment of a projectile according to a first aspect of the invention;
(4) FIG. 2a shows a side elevation cross sectional illustration of a further embodiment of a mine disposal projectile according to a first aspect of the invention;
(5) FIG. 2b shows a side elevation cross sectional illustration of a further embodiment of a projectile according to a first aspect of the invention when in use;
(6) FIG. 3a shows a side elevation cross sectional illustration of a further embodiment of a projectile according to a first aspect of the invention;
(7) FIG. 3b shows a side elevation cross sectional illustration of a further embodiment of a projectile according to a first aspect of the invention when in use;
(8) FIG. 4a shows a side elevation cross sectional illustration of a further embodiment of a projectile according to a first aspect of the invention;
(9) FIG. 4b shows a side elevation cross sectional illustration of a further embodiment of a projectile according to a first aspect of the invention when in use;
(10) FIG. 5a shows a side elevation cross sectional illustration of a further embodiment of a projectile according to a first aspect of the invention;
(11) FIG. 5b shows a side elevation cross sectional illustration of a further embodiment of a projectile according to a first aspect of the invention when in use;
(12) FIG. 6a shows a side elevation cross sectional illustration of a further embodiment of a projectile according to a first aspect of the invention;
(13) FIG. 6b shows a side elevation cross sectional illustration of a further embodiment of a projectile according to a first aspect of the invention when in use; and
(14) FIG. 7 shows a flow diagram illustrating a method according to a second aspect of the invention.
(15) The drawings are for illustrative purposes only and are not to scale.
DETAILED DESCRIPTION
(16) FIGS. 1a and 1b show an illustration of an embodiment of the first aspect of the invention. A projectile 101 is shown, having a projectile body 102 comprising a nose portion 103 and a tail portion (not shown). In this embodiment the projectile body is approximately 10 cm the length (along the longitudinal axis) and has a diameter of approximately 3 cm. A first electrode 105 extends the length of the projectile, with a first portion of the first electrode 105 forming the nose portion 103 and a second portion of the first electrode 105 extending internally along the length of the tail portion (not shown). The nose portion 104 is substantially conical in shape. A second electrode 106 is tubular in shape and is arranged coaxially about a portion of the length of the first electrode 105. The second electrode 106 forms the outer surface of the tail portion 104 of the projectile body 102. In this embodiment the first and second electrodes are formed from tungsten. An insulator 107 is arranged between the first electrode 105 and the second electrode 106 along the length of the tail portion 104. In this embodiment, the insulator 107 is a ceramic, for example, Boron Nitride or Cubic Zirconia, but insulator 107 could equally be another suitable insulating material, for example, a plastic, such as, PTFE or ABS. The first electrode and the second electrode are separated along the longitudinal axis by distance A, which in this embodiment is approximately 2 mm in distance. such that an electrical discharge can flow between the first electrode 105 and the second electrode 106, for example in the direction indicated by arrow B. The surface of the first electrode 105 and the second electrode 106 are arranged so as to be connectable to a source of electrical energy by welding.
(17) FIGS. 2a and 2b show an illustration of a different embodiment of the first aspect of the invention. A projectile 201 is shown, having a projectile body 202 comprising a nose portion 203 and a tail portion (not shown). A first electrode 205 extends the length of the projectile, with a first portion of the first electrode 205 forming the nose portion 203 and a second portion of the first electrode 205 extending internally along the length of the tail portion (not shown). The nose portion 204 is substantially conical in shape. A second electrode 206 is tubular in shape and is arranged coaxially about a portion of the length of the first electrode 205. The second electrode 206 forms the outer surface of the tail portion (not shown) of the projectile body 202. An insulator 207 is arranged between the first electrode 205 and the second electrode 206 along the length of the tail portion (not shown). The first electrode and the second electrode are separated along the longitudinal axis such that an electrical discharge (not shown) can flow between the first electrode 105 and the second electrode 106. In FIG. 2b the projectile 201 is shown partially embedded within the mine 209 (partially shown) having penetrated the mine casing 210 (partially shown). The second electrode 206 is deformable such that on penetration of the mine casing a portion of the second electrode 208 contacts the insulator 207 so as to deform the portion of the second electrode 208 away from the projectile body and into the explosive material 211. Therefore, the separation distance through which the electrical discharge can flow is increased. The surface of the first electrode 205 and the second electrode 206 are arranged so as to be connectable to a source of electrical energy by welding.
(18) FIGS. 3a and 3b show an illustration of a further embodiment of the first aspect of the invention. A projectile 301 is shown, having a projectile body 302 comprising a nose portion 303 and a tail portion (not shown). A first electrode 305 extends the length of the projectile, with a first portion of the first electrode 305 forming the nose portion 303 and a second portion of the first electrode 305 extending internally along the length of the tail portion (not shown). The nose portion 304 is substantially conical in shape. A second electrode 306 is tubular in shape and is arranged coaxially about a portion of the length of the first electrode 305. The second electrode 306 forms the outer surface of the tail portion (not shown) of the projectile body 302. An insulator 307 is arranged between the first electrode 305 and the second electrode 306 along the length of the tail portion (not shown). The first electrode and the second electrode are separated along the longitudinal axis such that an electrical discharge (not shown) can flow between the first electrode 305 and the second electrode 306. The tail portion (not shown) has a flange 312 located at the opposing end from the nose portion 303. The flange 312 has a diameter greater than the rest of the projectile body 302. In FIG. 3b, the projectile 301 is shown partially embedded within the mine 309 (partially shown) having penetrated the mine casing 310 (partially shown). The flange 312 has controlled the degree of penetration of the projectile body 302 such that the nose portion 302 and a portion of the tail portion (not shown) have penetrated the mine casing 310 and are located internally to the mine 309. A portion of the tail portion (not shown) remains external to the mine. The surface of the first electrode 305 and the second electrode 306 are arranged so as to be connectable to a source of electrical energy by welding.
(19) FIGS. 4a and 4b show an illustration of a further embodiment of the first aspect of the invention. A projectile 401 is shown, having a projectile body 402 comprising a nose portion 403 and a tail portion 404. A first electrode 405 extends from the tip of the nose portion 403 of the projectile body 402 internally along a portion of the length or the tail portion 404. The tip of the nose portion 404 is formed from a portion of the first electrode 405. The nose portion 404 is substantially cylindrical in shape. A second electrode 406, being tubular in shape, is arranged coaxially about a portion the first electrode 405. The second electrode 406 forms a portion of the outer surface of the nose portion 403 of the projectile body 402. An insulator 407 is arranged between the first electrode 405 and the second electrode 406 along a portion of length of the tail portion 404. The first electrode 405 and the second electrode 406 are separated along the longitudinal axis such that an electrical discharge (not shown) can flow between the first electrode 405 and the second electrode 406. The projectile 401 comprises and integral source of electrical energy, in the form of a capacitor 413. The capacitor 413 is charged using the integral battery 414 which is controlled by the integral battery control module 415. The capacitor is electrically connected to the second electrode 406 via the tail portion casing 418. The capacitor is arranged in the tail portion 404 between a first cavity 416 and a second cavity 417. The first and second cavities 416, 417 are filled with air. A compressible crumple ring 418 is located between the capacitor 409 and a keel 419. The keel 419 comprises a conductive switch element 420 to which the first electrode 405 is electrically connected. The capacitor is movable along the longitudinal axis of the tail portion 404 responsive to the penetration of the mine casing 410 by the projectile 401. Upon penetration of the mine casing 410 the capacitor 413 moves along the longitudinal axis towards the nose portion 403 by compressing the crumple ring 418. As the capacitor 413 moves towards the nose portion 403 the first cavity 416 becomes reduced in volume and the second cavity 417 becomes increased in volume. Air can pass from the first cavity 416 to the second cavity 417 through channels around the outer edge of the capacitor (not shown). During impact with the mine casing the air transfer between the first and second cavities 416, 417 produces a damping effect reducing the impact stress on the capacitor 413. The movement of the capacitor 413 towards the nose portion 403 closes the distance between the switch element 417 and the capacitor 413 enabling an electrical current to pass from the capacitor 413 to the switch element 417 and along the length of the first electrode 405 thereby electrically connecting the capacitor to the second electrode 406. As second electrode becomes electrically connected to the capacitor an electrical discharge flows between the first electrode 406 and the second electrode 407 through the explosive material 411.
(20) The tail portion 404 has a diameter greater than the nose portion 403 of the projectile body 402. The tail portion 404 thereby acts as a retaining means controlling the degree of penetration of the projectile 401 into the mine 409. FIG. 4b shows the projectile 401 partially embedded within the mine 409 (partially shown) having penetrated the mine casing 410 (partially shown). The degree of penetration of the projectile body 402 in controlled such that the nose portion 402 has penetrated the mine casing 410 and is located internally to the mine 409 and the tail portion 404, being of greater diameter than the nose portion, 403 remains external to the mine 409.
(21) FIGS. 5a and 5b show an illustration of a further embodiment of the first aspect of the invention. A projectile 501 is shown, having a projectile body 502 comprising a nose portion 503 and a tail portion 504. A first electrode 505 extends from the tip of the nose portion 503 of the projectile body 502 internally along a portion of the length or the tail portion 504. The tip of the nose portion 504 is formed from a portion of the first electrode 505. The nose portion 504 is substantially cylindrical in shape. A second electrode 506, being tubular in shape, is arranged coaxially about a portion the first electrode 505. The second electrode 506 forms a portion of the outer surface of the nose portion 503 of the projectile body 502. The second electrode 506 extends internally along a portion of the length or the tail portion 504. An insulator 507 is arranged between the first electrode 505 and the second electrode 506 along a portion of the length of the nose and the tail portions 503, 504. The first electrode 505 and the second electrode 506 are separated along the longitudinal axis such that an electrical discharge (not shown) can flow between the first electrode 505 and the second electrode 506. The projectile 501 comprises and integral source of electrical energy, in the form of a capacitor 513. The capacitor 513 is charged using an integral battery 514 which is controlled by the integral battery control module 515. The first electrode 505 extends internally into the capacitor 513 and is thereby electrically connected to the capacitor. The second electrode 506 is partially arranged coaxially about the outer surface of the capacitor 515 and is thereby electrically connected to the capacitor. The capacitor is arranged in the tail portion 504 between a first cavity 516 and a second cavity 517 (which may form a combined cavity, or may be a pair of distinguishable differential pressure chambers). The first and second cavities 516, 517 may be filled with a compressible or incompressible medium (such as paraffin wax, silicone or air). The capacitor is movable along the longitudinal axis of the tail portion 504 responsive to the penetration of the mine casing 510 by the projectile 501. Upon penetration of the mine casing 510 the capacitor 513 moves along the longitudinal axis towards the nose portion 503 by compressing the wax located in the first cavity 516. During impact, heating of the projectile causes the wax to become at least partially molten. Holes (not shown) are provided in the tail portion casing 522 through which the wax located in the first cavity can flow and escape the mine projectile casing. The compression and evacuation of the wax from the first cavity 516 produces a damping effect reducing the impact stress on the capacitor 513 and any associated electronics.
(22) The second electrode 506 is deformable such that on penetration of the mine casing, as the capacitor 513 moves towards the nose portion 503, a portion of the second electrode 508 contacts the insulator 507 deforming the portion of the second electrode 508 away from the projectile body 502 and into the explosive material 511. Therefore, the electrodes form an electrical current path through the explosive material.
(23) The tail portion 504 has a diameter greater than the nose portion 503 of the projectile body 502. The tail portion 504 thereby acts as a retaining means controlling the degree of penetration of the projectile 501 into the mine 509. FIG. 5b shows the projectile 501 partially embedded within the mine 509 (partially shown) having penetrated the mine casing 510 (partially shown). The degree of penetration of the projectile body 502 is controlled such that the nose portion 502 has penetrated the mine casing 510 and is located internally to the mine 509 and the tail portion 504, being of greater diameter than the nose portion, 503 remains external to the mine 509.
(24) FIGS. 6a and 6b show an illustration of a further embodiment of the first aspect of the invention. A projectile 601 is shown, having a projectile body 602 comprising a nose portion 603 and a tail portion 604. Except where stated like parts in FIGS. 6a and 6b match those in the embodiment shown in FIGS. 5a and 6b.
(25) First electrode 605 and second electrode 606 extend forward through the nose portion 603. In this embodiment an outer wall of the nose portion (or in this case also of the projectile body) forms the second electrodes 606. A conduction path is established (in event that there is a dielectric surrounding the nose portion) between the pointed tip of second electrode 606 and the circular tip of first electrode 605, but otherwise are separated by an insulator 607. The first electrode 605 and the second electrode 606 are separated along the longitudinal axis such that an electrical discharge (not shown) can flow between the first electrode 605 and the second electrode 606.
(26) The projectile 601 comprises and integral source of electrical energy, in the form of a capacitor 613. The capacitor 613 is charged using an integral battery 614 which is controlled by an integral battery control module (not shown). The first electrode 605 is connected to the capacitor 613 by a sliding electrical connection 618, and is thereby electrically connected to the capacitor. The second electrode 606 is connected to the capacitor only in the event that the capacitor slides within a cavity within the tail portion 604 forwards to connect to pressure/touch or sliding electrical connector 619.
(27) The cavity may be filled with a compressible or incompressible medium (such as paraffin wax, silicone or air) so long as this does not prevent electricity flowing across the two connectors 618 and 619. The capacitor is movable along the longitudinal axis of the tail portion 604 responsive to the penetration of the mine casing 610 by the projectile 601. Upon penetration of the mine casing 610 the capacitor 613 moves along the longitudinal axis towards the nose portion 603 (e.g. by compressing/displacing the substance/wax) located in the cavity. If a wax or wax-like substance is used then during impact, heating/heating/shear forces caused by the projectile causes the wax (or other substance) to become at least partially molten. Holes (not shown) are provided in the tail portion casing 622 through which the wax located in the cavity can flow and escape the mine projectile casing. The compression and evacuation of the wax from the cavity produces a damping effect reducing the impact stress on the capacitor 613 and any associated circuitry/electronics that may slide along with it.
(28) The tail portion 604 has a diameter greater than the nose portion 603 of the projectile body 602. The tail portion 604 thereby acts as a retaining means controlling the degree of penetration of the projectile 601 into the mine 609. FIG. 6b shows the projectile 601 partially embedded within the mine 609 (partially shown) having penetrated the mine casing 610 (partially shown). The degree of penetration of the projectile body 602 is controlled such that the nose portion 602 has penetrated the mine casing 610 and is located internally to the mine 609 and the tail portion 604, being of greater diameter than the nose portion, 603 remains external to the mine 609.
(29) The nose portion 603 shows a space in front of the central electrode, behind the penetrating tip (which in any embodiment could be a dense and hard penetrating material such as tungsten). In the case that the first electrode is cylindrical around the second electrode then this is a cavity which could filled with the aforementioned energetic material. Alternatively if the first electrode is not cylindrical, but rather perhaps in the form of two rods either side of the second electrode, then the space will become filled with the explosive within the mine. In the case that another material such as salt water is used, this may be introduced between the electrodes during use, either by the user or by immersing the projectile into the material (water, typically salt water). In this case the nose portion has an ingress path (not shown) to allow the material to ingress between the electrodes.
(30) Note that the term ‘between’ relates to the path that an electrical discharge would take between the two electrodes—if there is an insulator in the way of a straight line electrical discharge, then the discharge path will instead go around the insulator and this path should be considered to be between the electrodes irrespective of it not being a straight path.
(31) FIG. 7 shows an illustration of a further embodiment of the first aspect of the invention. A projectile is provided according to a first aspect of the invention (630) as illustrated in the embodiment of FIGS. 2a and 2b. The projectile is launched from a launch tube towards a mine (631). The casing of the mine is pierced by the projectile (632) such that the projectile is partially embedded within the mine as shown in the embodiment of FIG. 2a. A voltage is applied between the first electrode and the second electrode of the projectile wherein the voltage is of sufficient magnitude to so as to cause an electrical discharge to flow between the first electrode and the second electrode through the explosive material of the mine so as to initiate an explosive reaction. (633).
