Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F42—AMMUNITION; BLASTING
  • F42B—EXPLOSIVE CHARGES, e.g. FOR BLASTING, FIREWORKS, AMMUNITION
  • F42B3/00—Blasting cartridges, i.e. case and explosive
  • F42B3/02—Blasting cartridges, i.e. case and explosive adapted to be united into assemblies
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F42—AMMUNITION; BLASTING
  • F42B—EXPLOSIVE CHARGES, e.g. FOR BLASTING, FIREWORKS, AMMUNITION
  • F42B1/00—Explosive charges characterised by form or shape but not dependent on shape of container
  • F42B1/02—Shaped or hollow charges
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F41—WEAPONS
  • F41H—ARMOUR; ARMOURED TURRETS; ARMOURED OR ARMED VEHICLES; MEANS OF ATTACK OR DEFENCE, e.g. CAMOUFLAGE, IN GENERAL
  • F41H11/00—Defence installations; Defence devices
  • F41H11/08—Barbed-wire obstacles; Barricades; Stanchions; Tank traps; Vehicle-impeding devices; Caltrops
  • F41H11/11—Clearing or neutralising barbed wire obstacles
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F42—AMMUNITION; BLASTING
  • F42B—EXPLOSIVE CHARGES, e.g. FOR BLASTING, FIREWORKS, AMMUNITION
  • F42B3/00—Blasting cartridges, i.e. case and explosive

Definitions

• the present invention relates to an explosive charge, particularly a charge suitable for use in a so-called "Bangalore Torpedo".
• a conventional explosive charge is described in WO2007/099362.
• the charge has one or more longitudinal concave grooves. Upon explosion, the contour of the groove results in a focussing effect on the wall material. The groove does not reduce the local thickness of the wall of the charge.
• Another conventional explosive charge is described in GB-A-2214618.
• the inner face of the lining is formed with a set of V-shaped grooves interlinked around the axis of the charge.
• the grooves reduce the local thickness of the lining and result in material being ejected in a plurality of shaped charge jets one from each outward facing V-shaped region of the lining.
• a first aspect of the invention provides an explosive charge comprising an elongate casing with elongate grooves running along the casing, each groove locally reducing the thickness of the casing, wherein the grooves are distributed in two or more groups around the circumference of the casing and the edge-to-edge spacing between each adjacent pair of grooves in a group is less than the edge-to-edge spacing between each pair of adjacent groups.
• a second aspect of the invention provides a kit of parts comprising two or more charges according to the first aspect of the invention, each charge having a head end adapted to be coupled to the tail end of an adjacent charge, and a tail end adapted to be coupled to the head end of an adjacent charge.
• a third aspect of the invention provides a method of cutting an obstacle using the explosive charge of the first aspect of the invention, the method comprising detonating explosive material in a compartment of the casing, the detonation causing the casing to break at a pair of grooves in one of the groups and form a fragment from material between the pair of grooves, the fragment cutting the obstacle.
• the grooves are distributed uniformly around the circumference of the lining.
• the grooves are distributed non-uniformly around the circumference of the casing so that they are bunched together in two or more groups.
• the relatively small edge-to-edge spacing between each adjacent pair of grooves in a group results in the generation of high energy fragments which can cut efficiently through an obstacle.
• the edge-to-edge spacing between each groove in a group may be zero, but preferably it is greater than zero so that each groove has an edge which is separated from an adjacent edge of an adjacent groove by a non-grooved portion of the casing.
• Figure 1 is a plan view of an explosive charge
• Figure 2 is a longitudinal sectional view taken along a line B-B in Figure 1;
• Figure 3 is a transverse sectional view taken along a line A-A in Figure 1 ;
• Figure 4 is a close up transverse sectional view showing a pair of grooves
• Figure 5 is a perspective view showing a set of charges in use as a Bangalore torpedo.
• Figure 6 is a schematic sectional view showing the torpedo exploding.
• An explosive charge 1 shown in Figure 1 comprises an elongate casing 2 with grooves 3, 4 running along the external wall of the casing.
• Figure 3 is a transverse sectional view taken along a line A-A in Figure 1, which shows that there are four pairs of grooves distributed around the circumference of the casing. The grooves are all identical so only the pair 3, 4 will be described in detail with reference to Figure 4.
• Each groove is V-shaped with a depth d.
• Each groove locally reduces the thickness of the casing, so the thickness ti of the casing at the bottom of each groove is less than the thickness t 2 in the un-grooved portion between adjacent pairs of grooves.
• the grooves 3, 4 are separated from each other by a small non-grooved portion 10 of the casing in which the thickness of the casing is substantially constant.
• each groove subtends an angle ⁇ g i of only about 4° and the edge-to-edge angular spacing ⁇ g2 between the edges of adjacent grooves within a pair is only about 2°. Therefore each pair subtends an angle ⁇ g3 between its two outer edges of about 10°, and the edge-to-edge angular spacing ⁇ pl
• the internal wall of the casing is circular in cross- section for ease of manufacture and to maximise the space available for explosive material.
• the casing has an internally threaded head end 11 adapted to be screwed to the tail end of an adjacent charge, and an externally threaded tail end 12 adapted to be screwed to the head end of an adjacent charge.
• Figure 5 shows the device in use as a Bangalore torpedo being prepared to clear a path through a series of wires 20 (for instance barbed wire or razor wire).
• a number of casing units 21, 22 (in this case two, but optionally more than two) are screwed together head to tail.
• An explosive charge (not shown) is contained inside the torpedo along its full length.
• a nose cone 23 is screwed to the head end of the front casing unit, and a detonator housing 24 with an initiator is screwed to the tail end of the rear casing.
• the torpedo is fed under the barbed wire and placed on the ground with two pairs of grooves facing up and oriented at approximately +/- 45° to the vertical.
• the charge is then detonated, causing the casing to break initially at the bases of the eight grooves where the thickness t ⁇ is at a minimum.
• the casing material between the grooves forms four small pre-defined fragments which are ejected at approximately +/- 45° to the vertical.
• the fragments from the two downwardly pointed pairs of grooves impact the ground and are not shown in Figure 6.
• the fragments 25, 26 from the two upwardly pointed pairs of grooves are ejected upwardly and cut the barbed wire at locations 27 and 28 respectively, clearing a path through the obstacle.
• the relatively large volume of casing between the pairs of grooves generates a set of relatively small and low energy particles 29, 30, 31 which have less cutting effect than the fragments 25, 26.
• Figure 6 does not show the true shape of the fragments 25, 26 or lower energy particles 29-31 but merely intends to show the mode of operation schematically.

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• Engineering & Computer Science (AREA)
• General Engineering & Computer Science (AREA)
• Drilling And Exploitation, And Mining Machines And Methods (AREA)

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• 2009
  • 2009-04-01 GB GB0905688.8A patent/GB2469099B/en not_active Expired - Fee Related
• 2010
  • 2010-01-25 AU AU2010200277A patent/AU2010200277B2/en not_active Ceased
  • 2010-03-26 CA CA2757111A patent/CA2757111A1/en not_active Abandoned
  • 2010-03-26 US US13/258,815 patent/US20120090491A1/en not_active Abandoned
  • 2010-03-26 EP EP10711703A patent/EP2414768A1/en not_active Withdrawn
  • 2010-03-26 WO PCT/GB2010/050514 patent/WO2010112900A1/en active Application Filing
• 2011
  • 2011-01-18 HK HK11100462.6A patent/HK1146311A1/xx not_active IP Right Cessation

Non-Patent Citations (1)

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