GB2230846A

GB2230846A - Reduced recoil firearm

Info

Publication number: GB2230846A
Application number: GB9008795A
Authority: GB
Inventors: Derek John Horn; Andrew Donald Shelle Mcfarlane; Jack William Comley; George Adrian Castle Davis
Original assignee: PRECISION AB
Current assignee: PRECISION AB
Priority date: 1989-04-19
Filing date: 1990-04-19
Publication date: 1990-10-31
Also published as: GB8908823D0; GB9008795D0

Abstract

A reduced recoil or a recoiless dearmer comprises a plug 12, a breech 14 and a barrel (10), the breech 14 being capable of containing a remotely fireable cartridge 46, the breech 14 being sealingly engageable with the breech plug 12, and the barrel (10) receiving and discharging a dearming projectile 92. The barrel (10) is preferably elongated and has three gas ports 30, (32) and (34) capable of deflecting a proportion of the explosive discharge of the cartridge when fired to reduce or remove the recoil of the dearmer. Suitable projectiles and loading tools are disclosed <IMAGE>

Description

FIREARM The present invention relates to a firearm and in particular to a dearmer and more particularly to a dearmer which has reduced or no recoil.

During a conflict, bombs are genereally scattered by an enemy, for example, on runways. Many of these may not be discharged on contact with the runway. As a result after a bombing raid has been completed, it may be necessary to clear the runway to allow it to be used for incoming and outgoing aircraft. There are also many other situations where explosives need to be cleared from an area without damage to the area.

Currently bombs are two part mechanisms having a fuse or detonator and a main body portion formed from explosive. Bombs are generally dearmed by removing the fuse or detonator from the explosive without the explosive being damaged or exploding thus causing damage to the surroundings, this being the purpose of bombs.

The main problems with existing dearmers is that they are crude firearms which are difficult to control. In addition there is significant recoil of the dearmer possibily causing damage to the surroundings. As a result it is necessary to sandbag an area making the whole process complicated in terms of equipment and personnel.

The present invention attempts to overcome the disadvantages of the current dearmers by providing a directable dearmer which has reduced or no recoil.

In addition the present invention attempts to provide a dearmer in which a dearming slug can penetrate a 10 millimetre steel plate.

According to the present invention there is provided a reduced recoil or a recoiless dearmer comprising a plug, a breech and a barrel, the breech being capable of containing a remotely fireable cartridge, the breech being sealingly engageable with the breech plug in order to retain the remotely fireable cartridge within the breech, the breech being capable of sealingly engaging with the barrel to prevent passage of the remotely fireable cartridge but to allow the explosive discharge thereof to be transmitted through the barrel, the barrel being elongated and capable of receiving and discharging a dearming projectile on discharge of the cartridge, the barrel having at least one gas port therein capable of deflecting a proportion of explosive discharge of the cartridge when fired to reduce or remove recoil of the dearmer.

The breech and barrel may be a single unit or a two part arrangement having a sealing engagement by means of a male and female screw thread.

In the preferred embodiment the barrel of the present invention has more than one gas port therein.

Preferably three gas ports are provided although the number of gas ports is only restricted by the strength of the barrel.

The dearmers of the present invention are often used in critical situations such as in a battle zone under fire when it is necessary to use the dearmer quickly and efficiently possibly at night. Accordingly it is preferred that the various parts of the dearmer are easily engageable with the adjacent part. Thus the breech plug preferably has a large male screw thread on the plug which engages with a female screw thread on the breech of the dearmer.

It is also preferred that the plug has a knurled outer periphery to enable the operator to feel the breech plug.

Axially arranged may be a central small diameter passageway to allow electrical wires from a cartridge to pass through the breech plug to allow remote firing of the cartridge.

In a preferred embodiment an electrically dischargeable EOD propelling cartridge is used which contains explosive but no projectile. Such a cartridge has two firing wires in order to detonate the cartridge. The firing wires pass through the axial passageway of the breech plug. Such a cartridge has a groove and flange on the firing end of the cartridge which can mate with an optional arcuate partial flange on the breech plug.

The breech is generally cylindrical and has a further male thread at its discharge end which sealingly engages with the female thread in the barrel. The barrel end of the breech preferably has a restricted diameter in order to prevent the cartridge from passing through the breech.

Although the breech and the barrel sealingly engage by means of a large diameter screw thread, a spaced portion to provide a tether loop and anti-roll sleeve may also be included. In the case where the breech and barrel is a single unit the breech plug may be adapted to provide a tether loop and an anti-roll portion.

It is preferred that the barrel has a cylindrical body with female thread which sealingly engages with the male thread of the breech.

It is preferred that each portion of the dearmer has a similar outer diameter.

In a preferred embodiment one or more of the male threads of each portion of the dearmer, may have a longitudinal groove therein to provide a self cleaning groove. The groove is preferably longitudinal i.e.

parallel to the axis of the dearmer and allows any grit or dirt to pass to the groove and be removed.

It is preferred that the barrel of the present invention is as long as possible in order to provide guidance for the projectile fired therefrom. However in this type of equipment lengthening the barrel causes problems both as far as recoil are concerned and as far as damage to the dearmer is concerned. Excess gas pressure is vented so the projectile [slug] needs to be in a guarded tube for a longer time because of the lower gas pressure.

In order to dissipate the explosive discharge from the cartridge upon firing of the cartridge to cause movement of the projectile, it is preferred that there are one or more gas ports capable of deflecting gases emerging from the cartridge in the opposite direction to the discharge from the cartridge. The gas ports are preferably eliptical arranged i.e. egg shape in cross section. The vent in the internal barrel wall may have a small eliptically shape whereas the vents on the outer barrel wall have a larger eliptical shape, the opening in the barrel wall at the forward end, i.e. the end furthest from the discharge of the cartridge, being substiantially perpendicular to the longitudinal axis of the dearmer.

Thus, as a cartridge is discharged explosive gases from the cartridge pass up the barrel. As they reach the gas port the explosive gases can discharge both longitudinally and axially. The force of the gases is applied to the gas vent causing a force to be applied to the forward portion of the gas ports causing a reaction in the barrel causing the barrel to move forwards. This forward motion of the muzzle counteracts the reaction of the cartridge moving axially and in a direction away from the moving projectile i.e. it counteracts the recoil of the cartridge. Although eliptically shaped gas ports are described, any suitable shape may be used to reverse the thrust of the gases from the discharge cartridge.

The present invention will be further described by way of example only, with reference to the accompanying drawings in which: Figure 1 shows a perspective view of the present invention when assembled.

Figure 2 shows components of the present invention in a disassembled form.

Figure 3 provides a longitudinal cross section of the component parts of the present invention.

Figure 4 shows a plan view of the breech plug of the present invention.

Figure 5 shows a perspective view of the anti-roll sleeve.

Figure 6 shows preferred examples of projectiles of the present invention.

Figure 7 shows a cleaning loading aligning tool for use with the present invention.

Referring to Figure 1, there is provided a dearmer generally designated as 10 having a breech plug 12, a breech 14 and a barrel 16. The dearmer 10 further includes an anti-roll sleeve 18 having attached thereto a shackle 20. Each component has a small circular holes 22, 24 and 26 to allow the location of one or more C spanners 28 to assist in assembly - disassembly of the dearmer. The barrel 16 has three gas ports 30, 32 and 34 located equilaterally around the circumference of the barrel 16.

Although three gas ports 30 are described, it is only necessary to have one gas port for the present invention to operate satisfactorily.

The gas ports 30, 32 and 34 are generally elliptically shaped in a preferred embodiment. The outer sides of the gas port being significantly greater in size than the inner portion which penetrates the inner wall of the barrel 16. The gas ports are situated intermediate to the ends of the barrel 16. The position of the gas ports in relation to the ends of the barrel can be varied according to the extent of the recoil required in the firearm when in use.

Referring to Figures 2 and 3, similar parts are described with similar numerals as shown in Figure 1. The breech plug 12 has a male thread 36 thereon which mates with a female thread 38 [as shown in Figure 3]. A further partial flange 40 having a receiving groove 42 therein receives the flange 44 of a cartridge 46. The cartridge 46 is preferably a remotely fireable cartridge such as an electrically dischargeable [EOD] propelling cartridge which contains explosive but no projectile. Such a cartridge has two firing wires 50 and 52 which are used to initiate the cartridge 46. The firing wires 50 and 52 are passed through a longitudinal passage 54 in the breech plug 12.

Located in the breech plug 12 along the knurled edge, as previously described, is a small hole 22 which receives a C spanner 28 used for assembling and disassembling the firearm of the present invention.

The breech 14 includes a barrel 56 which receives the cartridge 46. The leading end [neck]of the cartridge 58, i.e. the end of the cartridge from which explosive is discharged on initiation, abuts against the shoulder 60 at the firing end of the chamber 56. The chamber 56 is preferably shaped or tapered to receive the cartridge 46.

The chamber 56 continues in a narrow channel 62 which extends through a further male thread 64 terminating in a further cylindrical muzzle end of breech 66. The muzzle end of breech 66 has a flat 68 and breech sealing register 70. The flat 68 mates with a locating flat 72.

Each of the male threads 36 from the breech plug and 64 from the breech provides a sealing joint with its adjacent abutting part using a suitably large screw thread to enable the components to be put together rapidly in difficult situations. In addition to the suitable screw thread which is preferably as large as possible while still maintaining the sealing nature of the joint, there is further included a longitudinal groove 74 on the breech plug and a further longitudinal groove 76 on the breech.

The purpose of the longitudinal groove is to provide a self cleaning groove for the screw threads 36 and 64 respectively such that any dirt grit sand etc. which collects in the screw thread will be removed to the longitudinal groove on screwing the component in either direction.

A further component which can be included, although as a preferred feature, is a tether loop and anti-roll sleeve 78, more particularly shown in Figure 5. The tether loop and anti-roll sleeve 78 preferably includes a hole 80 to which a tethering lead can be attached, for example by means of a shackle. The anti-roll sleeve 78 is preferably of a loose fit such that it may be rotated around the periphery of the breech 14 and the barrel 16 when the breech 14 and barrel 16 are securely located together.

The barrel 16 has a female thread 82 which receives the male thread 64 as well as the breech sealing register 70 and flat 66.

The barrel 16 further includes the three gas ports 30, 32 and 34 equilaterally arranged around the circumference of the outer wall of the barrel. The gas ports 30, 32 and 34 pierce the wall and reduce in size as they reach the inner wall of the barrel.

Although three gas ports have been described, as previously explained, it is only essential that one gas port be part of the present invention. Alternatively, it is possible to use two, four or more gas ports in order to provide the necessary control of recoil of the present invention.

Continuing the description of the actual embodiment now shown, the gas port 30 has an elliptically expanding gas port i.e. the dimensions of the ellipse in the inner wall of the barrel 16 are significantly smaller than the dimensions of the ellipse in the outer wall of the barrel 16. The largest radius of curve of the ellipse substantially coincide to form a substantially perpendicular wall extending from the inner wall of the barrel to the outer wall of the barrel forming a gas detection wall 84. The end of the barrel 16 is generally counter sunk on the inner periphery of the wall to protect the barrel 16 on dropping.

The gas ports 30, 32 and 34. are preferably positioned intermediate at the ends of the barrel 16 at about a quarter of the length from the commencement of the female thread 82 of the barrel 16. It has been found that this position provides the suitable gas deflection ability of the ports 30, 32 and 34. However the gas ports may be positioned at any distance along the barrel 16 in order to provide suitable recoil or reduced recoil of the firearm of the present invention.

Although eliptically shaped gas ports have been described, other shapes of gas ports may be used as is determined suitable for a specific application.

Referring to Figure 4, the plan view of the breech plug 12 is shown showing the locating flange 38 and the male thread 40 as well as the firing wire passageway 74.

Turning to Figure 6, suitable projectiles are shown. Figure 6a shows a generally cylindrical projectile 86 preferably having two circumferential grooves 88 and 90 extending round the periphery of the projectile 86 and capable of receiving 0 rings, such as rubber 0 rings, to provide a suitable seal within the barrel 16. A single 0 ring may be used in the alternative, although in some instances projectiles with either no 0 rings or more than two 0 rings may also be used. The dimensions of the projectile are such that they can be slideably inserted in the barrel 16 with the 0 rings 88 and 90 providing sufficient resistence to movement in the barrel when it is in any orientation and gas sealing ability. Figure 6b shows alternative projectile 92 having a chisel end 94 with O rings 96 and 98 in position.

Turning to Figure 7, Figure 7a shows a complete loading tool 100 having a detachable portion 102 engagable by a screw thread 104. Figure 7a shows the loading tool 100 with a handle 106 and a flat end 108 for pushing the projectile in to the barrel 60. Figure 7b shows an alternative detachable end 110 having a brush head 112 of suitable diameter to closely fit the internal dimensions of the barrel 16 in order that it may be cleaned. Figure 7c shows a further detachable end 114 having a forked portion 116 suitable for loading and locating the chisel ended projectile 92.

Three gas ports 30, 32 and 34 are used in order that any one or two of the gas ports may be operable at any one time if the dearmer 10 of the present invention is positioned on the ground. In this circumstance, one of the gas ports 30, 32 and 34 may be blocked by its location adjacent to the ground.

The location of the gas ports 30, 32 and 34 is also related to the size of the projectiles to be used in the barrel 16. The projectiles, for example, the chisel ended projectile 92 may be positioned in the barrel 16 such that the chisel end shows partially through the gas ports in order that the location and the orientation of the chisel end may be seen by the user. To facilitate location of the projectile notches 118, 120 and 122 are provided in the various parts i.e. the breech plug 12, the breech 14, and the barrel 16. This facilitates the location and orientation of those parts in the dark or in difficult circumstances by feel.

Although a three part firearm 10 of the present invention has been described, one of the advantages of the present invention is that the barrel 16 may be replaced by a shorter barrel of conventional type as is necessary. Of course, a shorter barrel without gas points would not have the advantages of the present invention and would have all the disadvantages of the prior art. In certain situations however it may be thought necessary to use such a short barrel.

In a further alternative embodiment it is possible that the present invention may be made up of two major component parts i.e. the breech 14 and the barrel 16, may be a single unit having all the same parts as previously described i.e. a barrel 56 shaped to receive the cartridge 46 having a narrow channel 62 extending into the main body of the barrel without the male thread 64 and the female thread 82. Three gas ports 30, 32 and 34 may be equilaterally arranged around the circumference of the outer wall of the barrel. The breech plug 12 may have a flat portion on either side of the screw thread to allow the inclusion of an anti-roll restraint. The anti-roll restraint also facilitates screwing and unscrewing of the breech plug.

The operation of the present invention will now be described-with reference to the drawings.

The component parts, i.e. the breech plug 12, the breech 14, the barrel 16 and the tether loop and anti-roll sleeve 18 are assembled as shown in Figure 1. A projectile for example such as the chisel end projectile 92 is inserted from the firing end 124 of the barrel 16. It is pushed down the barrel as far as possible. As previously explained, the dimensions of the projectile 92 are preferably such that the chisel shows in the gas ports 30, 32 and 34. The loading tool 100 having the locating end 114 is used to ensure that the orientation of the chisel end 94 is in the desired position for firing.

Prior to assembly of the breech plug 12 and the breech 14 a remotely operable EOD cartridge 46 is located by means of its flange 44 in the parcel flange 42 with the operating wires 50 and 52 passing through the passage 54.

The screw threads 36 and 38 are mated causing sealing engagement between the breech plug 12 and the breech 14 positioning the cartridge 46 in the barrel 56. The end of the cartridge 58 abuts the flat 60 of the barrel.

The operating wires 50 and 52 are applied to a suitable remote firing mechanism some distance away. The dearmer 10 is arranged such that it is properly orientated in relation to the bomb etc. to be dearmed. A firing pulse is applied to firing wires 50 and 52 which causes the cartridge 46 to discharge explosively propelling the projectile 92 along the barrel 16 in order to hit the fuze bomb etc. in the desired position. The explosive gases released from the cartridge 46 pass through the barrel to the gas ports 30, 32 and 34 and at this point they expand laterally from the axis of the dearmer 10 and outwardly through the gas ports applying a force to the gas ports and wall 84. The force applied causes the direction of the gases to be reversed applying an equal and opposite force on the wall 84 which counteracts the recoil of the cartridge 46 on discharge.

Without wishing to be bound by theory of operation of the present invention, it has been found that approximately one fifth of the power of the cartridge is used in propelling the projectile 92 through the barrel of the barrel 16 the remaining four fifths of the power cartridge being used in explosively propelling gases therefrom. By directing the force of the gases through the gas ports 30, 32 and 34 an opposite reaction to the recoil of the cartridge is produced in the barrel 16. Although the gas ports are shown in a particular position, it should be recognized that by positioning the gas ports 30, 32 and 34 towards the discharge end of the barrel 16 less force will be used in counteracting the recoil than if the position of the gas ports 30, 32 and 34 was further away from the discharge end of the barrel 16.By suitably positioning the gas ports in relation to the power of the EOD cartridge to be used, it is possible to provide no recoil or even a negative recoil i.e. the ability to cause the dearmer of the present invention to move in the same direction as the projectile which is discharged therefrom.

Prior to the present invention various methods of counteracting recoil had been thought of, such as placing two conventional dearmers back to back and concurrently discharging the cartridges therefrom, such that the recoil from each counteracts the other.

It has been shown in tests of the present invention that it is possible to cause a projectile to be fired from the dearmer such that it will pass through 10 millimetre steel plate positioned perpendicularly and vertically at a distance of 75-150 mm from the barrel 16 of the dearmer 10.

Thus although it is possible that only a proportion of the power of the cartridge is being used in causing motion in the projectile, this is still sufficient to provide the necessary force and penetrating ability of the projectile.

In addition, the present invention has the advantage that much of the force of the cartridge which otherwise would be destructive to the dearmer 10 itself is dissipated and used to control recoil which in its term prolongs the useful life of the dearmer. As a result the dearmer of the present invention has a 1000 round life because of the lack of destructive forces thereon.

Claims

1. A reduced recoil or a recoiless dearmer comprising a plug, a breech and a barrel, the breech being capable of containing a remotely fireable cartridge, the breech being sealingly engageable with the breech plug in order to retain the remotely fireable cartridge within the breech, the breech being capable of sealingly engaging with the barrel to prevent passage of the remotely fireable cartridge but to allow the explosive discharge thereof to be transmitted through the barrel, the barrel being elongated and capable of receiving and discharging a dearming projectile on discharge of the cartridge, the barrel having at least one gas port therein capable of deflecting a proportion of explosive discharge of the cartridge when fired to reduce or remove recoil of the dearmer.

2. A dearmer as claimed in Claim 1 wherein the breech and barrel are a single unit.

3. A dearmer as claimed in Claim 1 or Claim 2 having more than one gas port therein.

4. A dearmer as claimed in Claim 3 having three gas ports spaced an equal distance from one another around the circumference of the barrel.

5. A dearmer as claimed in any one of the preceding claims having an anti-roll device attached to the breech of the dearmer.

6. A dearmer as claimed in any one of the preceding claims wherein each gas port is elliptical in shape reflecting the explosive gas in the opposite direction to the travel of the discharged dearming projectile.

7. A dearmer as claimed in Claim 1 substantially as hereinbefore described with reference to the accompanying drawings.