US20150083010A1 - Practice Projectile - Google Patents
Practice Projectile Download PDFInfo
- Publication number
- US20150083010A1 US20150083010A1 US13/611,654 US201213611654A US2015083010A1 US 20150083010 A1 US20150083010 A1 US 20150083010A1 US 201213611654 A US201213611654 A US 201213611654A US 2015083010 A1 US2015083010 A1 US 2015083010A1
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- United States
- Prior art keywords
- valve body
- valve
- practice
- pressure vessel
- firing
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- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F42—AMMUNITION; BLASTING
- F42B—EXPLOSIVE CHARGES, e.g. FOR BLASTING, FIREWORKS, AMMUNITION
- F42B8/00—Practice or training ammunition
- F42B8/12—Projectiles or missiles
- F42B8/20—Mortar grenades
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F42—AMMUNITION; BLASTING
- F42B—EXPLOSIVE CHARGES, e.g. FOR BLASTING, FIREWORKS, AMMUNITION
- F42B12/00—Projectiles, missiles or mines characterised by the warhead, the intended effect, or the material
- F42B12/02—Projectiles, missiles or mines characterised by the warhead, the intended effect, or the material characterised by the warhead or the intended effect
- F42B12/36—Projectiles, missiles or mines characterised by the warhead, the intended effect, or the material characterised by the warhead or the intended effect for dispensing materials; for producing chemical or physical reaction; for signalling ; for transmitting information
- F42B12/46—Projectiles, missiles or mines characterised by the warhead, the intended effect, or the material characterised by the warhead or the intended effect for dispensing materials; for producing chemical or physical reaction; for signalling ; for transmitting information for dispensing gases, vapours, powders or chemically-reactive substances
- F42B12/50—Projectiles, missiles or mines characterised by the warhead, the intended effect, or the material characterised by the warhead or the intended effect for dispensing materials; for producing chemical or physical reaction; for signalling ; for transmitting information for dispensing gases, vapours, powders or chemically-reactive substances by dispersion
Definitions
- the present invention relates to practice ammunition rounds. More specifically the invention relates to practice mortar bombs, a method of explosively releasing compressed fluid from a pressure vessel via an outlet valve system, a method of firing a practice mortar bomb, a method of propelling a practice mortar bomb and a kit of parts.
- a mortar is a weapon system typically used by infantrymen to provide indirect fire.
- Mortars are based around a mortar tube (the orientation of which is adjustable for aiming) down which is dropped a mortar bomb.
- Mortar bombs have a tail portion containing explosive propellant which is initiated by a firing pin at the bottom of the mortar tube. The resulting explosion combined with the tight fit of the bomb within the tube propels the bomb from the mortar barrel.
- a practice mortar bomb comprising optionally a pressure vessel and optionally an outlet valve system, the pressure vessel being arranged in use to optionally contain compressed fluid and the outlet valve system being arranged in use to optionally allow explosive release of the compressed fluid from the pressure vessel optionally upon activation of the valve system by a firing pin in a mortar tube.
- This practice mortar bomb may provide a relatively safe, inexpensive and yet realistic way of practicing the firing of a mortar.
- the practice mortar bomb further comprises an inlet valve system arranged in use to allow charging of the pressure vessel with fluid such that the fluid is compressed within the pressure vessel.
- the inlet valve system may provide a convenient way of filling the pressure vessel and may also allow re-use of the mortar bomb by re-filling the pressure vessel via the inlet valve system. This may make repeated practice considerably less expensive.
- the inlet valve system comprises a one-way valve allowing storage of the compressed fluid in the pressure vessel once charged.
- the one-way valve may offer a convenient way of allowing filling of the pressure vessel and the retention of compressed fluid for an extended period thereafter.
- the inlet valve system is positioned at a head end of the pressure vessel. Positioning of the inlet valve system in this way may allow for a reduced impact on the appearance and performance of the practice mortar bomb so as it better resembles a standard mortar bomb in appearance and performance.
- the outlet valve system is positioned at a base end of the pressure vessel. This may lead to a more direct release of compressed fluid in the desired direction for firing of the bomb.
- the outlet valve mechanism comprises a valve seat and valve body, the valve body being mobile such that in use a valve seat end of the valve body is engageable with the valve seat to block the flow of fluid from the pressure vessel, and is disengageable from the valve seat to allow the flow of fluid from the pressure vessel.
- the outlet valve system is a pressure balance valve, being arranged such that in use, compressed fluid from the interior of the pressure vessel impinges on at least two opposed surfaces of the valve body, the resulting net force being towards the valve seat until the outlet valve system is activated, whereupon the net force is away from the valve seat.
- the pressure balance valve may be a particularly effective way of allowing explosive release of compressed fluid, as the compressed fluid itself may be used to move the valve body away from the valve seat and so open the outlet valve system. This may lead to a very rapid opening of the outlet valve system. Further the pressure balance valve may allow re-setting of the outlet valve system after explosive fluid discharge.
- a first of the opposed surfaces is a head end of the valve body and a second of the opposed surfaces, opposed to the first is a biasing surface proximate the valve seat end of the valve body.
- the outlet valve system further comprises a chamber arranged such that in use, compressed fluid in the chamber impinges on the head end of the valve body with sufficient force to cause engagement of the valve seat end of the valve body with the valve seat.
- the chamber may provide a convenient method of allowing compressed fluid to impinge on the head end, while also isolating (at least to an extent) the fluid in the chamber from fluid in the pressure vessel. This may mean that through discharging the chamber, at least some of the force biasing the valve body towards the valve seat may be removed.
- the practice mortar bomb is arranged such that in use, activation of the outlet valve system leads to the release of compressed fluid from the chamber at a faster rate than it is replenished, such that the force biasing the valve body towards the valve seat is reduced and the net force on the valve body is reversed so as it is away from the valve seat. This may allow for rapid opening of the outlet valve system to permit explosive release of compressed fluid from the pressure vessel.
- release of the compressed fluid from the chamber is controlled by a firing valve, operated in use directly or indirectly by a firing pin in a mortar tube. This may allow the firing pin in a standard mortar tube to initiate firing of the practice mortar bomb. In this way a specialist mortar tube may not be required, potentially increasing the realism of practice.
- the outlet valve system is arranged such that in use it re-sets before all of the compressed fluid has been explosively released from the pressure vessel. In this way a positive pressure may be maintained in the pressure vessel, helping to prevent the ingress of foreign material such as dust, sand and/or water into the practice mortar bomb. This may be particularly advantageous in view of the fact that the practice mortar bomb may dig into the earth on landing (at least to an extent).
- the outlet valve mechanism further comprises a cylinder in which the valve body moves and is contained in a close fit.
- the cylinder may be an effective way of guiding movement of the valve body and of creating the chamber adjacent the head end of the valve body.
- the chamber is defined by the cylinder and the head end of the valve body.
- the cylinder has one or more cylinder through bores arranged so that the interior of the pressure vessel is in fluid communication with the chamber, such that in use pressurised fluid passes from the pressure vessel into the chamber.
- the cylinder through bores may therefore allow charging of the chamber from compressed fluid in the pressure vessel, in order that the valve body may be biased towards the valve seat.
- a region proximate the valve seat end of the valve body is provided with one or more rebated portions, each creating a cavity between the cylinder and the valve body.
- the cavities may assist in creating one or more surfaces for implementation of the pressure balance valve.
- the rebated portions create the biasing surface of the valve body, arranged such that at least a component of a force applied towards the biasing surface would act to bias the valve body away from the valve seat.
- the rebated portions comprise chamfering of the valve seat end of the valve body that extends beyond the valve seat and into the cylinder when the valve seat end of the valve body is engaged with the valve seat.
- the chamfering may assist in locating of the valve seat end of the valve body within the valve seat, and it may conveniently also provide the biasing surface.
- one or more passages is provided passing through the cylinder wall allowing fluid communication between the interior of the pressure vessel and the cavities. This may allow fluid pressure to be applied to the biasing surfaces from the pressure vessel for implementing the fluid balance valve.
- fluid gaps are provided intermediate the passages and cavities, created by an increase in the diameter of the cylinder between the passages and the cavities. Where these fluid gaps have a relatively narrow diameter in comparison to the passages, the fluid gaps may be sufficient to cause the valve body to rapidly disengage the valve seat. Thereafter as the valve body clears the passages fluid may be explosively released via the passages which may be of a relatively large diameter.
- the head end of the valve body has a sufficient surface area such that if the same pressure were applied to the head end of the valve body and the biasing surface, the net force on the valve body would cause the valve seat end of the valve body to engage with the valve seat. This may ensure that the default condition of the outlet valve system is closed so as to prevent discharge of fluid from the pressure vessel until compressed fluid is discharged from the chamber.
- valve body has a valve body through bore passing from the head end of the valve body to the valve seat end of the valve body. This may provide a convenient path for discharging compressed fluid from the chamber when the outlet valve system is activated.
- the head end of the valve body through bore is provided with a firing valve seat.
- a firing valve body is provided which, when there is compressed fluid in the chamber, is biased by the compressed fluid into engagement with the firing valve seat. This may ensure that the default condition of the firing valve is closed, preventing the discharge of fluid from the chamber (and so the opening of the outlet valve system) until the valve is activated.
- a spring may be provided to increase the force biasing the firing valve body into engagement with the valve seat.
- a pin of smaller diameter than the valve body through bore extends from the firing valve body through the valve body through bore. This pin may provide a convenient method of activating the outlet valve system, in that pushing on the pin may open the firing valve, by raising the firing valve body from the firing valve seat.
- the pin is arranged to force the firing valve away from the firing valve seat when an end of the pin is impacted by a firing pin in a mortar tube.
- the pin may therefore act as an intermediary between the firing pin of the mortar tube and the firing valve body. It this way it may be possible to use a conventional mortar tube.
- the cylinder through bore and valve body through bore are arranged such that greater quantities of fluid at a given pressure are passable through the valve body through bore than through the cylinder through bore in a given time. This may ensure that for as long as the firing pin of the mortar tube is keeping the firing valve open, the chamber cannot re-charge with pressurised fluid. This may mean that the outlet valve system will open and remain open, at least until the bomb is fired.
- the practice mortar bomb further comprises a dummy fuse nose portion.
- the nose portion may mean that the practice mortar bomb is more like a standard mortar bomb, i.e. in terms of appearance and/or aerodynamic profile and/or shape and/or size and/or weight, thus potentially making its use in practice more realistic.
- the nose portion simulates a known mortar bomb fuse type. This may make the practice mortar bomb more like a standard mortar bomb, i.e. in terms of appearance and/or aerodynamic profile and/or shape and/or size and/or weight, thus potentially making its use in practice more realistic.
- the fuse may for example simulate a point detonation fuse, a proximity fuse, a mechanical time fuse, a multi-option fuse or a practice fuse.
- the nose portion is releasably engageable with the bomb. This may allow the nose portion to be interchangeable with alternatives simulating different dummy fuses, depending on the practice to be undertaken.
- the nose portion provides a cap over the inlet valve system. This may serve to protect the nose portion especially during impact of the practice mortar bomb on landing.
- the bomb further comprises a hollow tail portion, the interior of the tail portion being in fluid communication with the pressure vessel when the outlet valve system is open.
- the tail portion may allow more accurate simulation of the appearance of a standard mortar bomb. Further the tail portion may receive the explosively released fluid from the outlet valve system, allowing it to be directed.
- the tail portion comprises one or more ports allowing fluid communication between its interior and exterior.
- the ports may be used to direct explosively released fluid into a mortar tube below the level of the pressure vessel.
- the tail portion has a tail portion through bore arranged in use to receive at least one of the pin and, in use the firing pin of a mortar tube.
- the tail portion through bore may help to ensure that the firing pin of the mortar tube is properly aligned and received by the practice mortar bomb in order that it may displace the pin.
- the pin is of sufficient length and aligned with the tail portion through bore so as a firing pin of a mortar entering the tail portion through bore will impact and push against the pin so as to push the firing valve body away from the firing valve seat. This may help to ensure a proper contact between the pin and firing pin of a mortar tube.
- the practice mortar bomb has an overfill pressure release valve. This may be an effective safety feature against over charging of the pressure vessel.
- kit of parts comprising optionally one or more pressure vessels for practice mortar bombs in accordance with the first aspect and optionally one or more of the following:
- a method of explosively releasing compressed fluid from a pressure vessel via an outlet valve system comprising the steps of:
- the method further comprises re-charging the location from which compressed fluid has been released so as the net force is again towards the valve seat. This may allow the practice mortar bomb to be re-used by re-charging the pressure vessel.
- a method of firing a practice mortar bomb comprising optionally a pressure vessel and optionally an outlet valve system optionally arranged upon activation to explosively release at least a portion of a compressed air reservoir in the pressure vessel, the method comprising the steps of:
- the method further comprises collecting the practice mortar bomb for optional re-use. This may improve cost effectiveness of mortar practice.
- the method further comprises selecting a head portion for attachment to the practice mortar bomb before it is fired. This may allow a mortar user to more accurately simulate performing different fire missions by selecting different dummy fuse head portions.
- a method of propelling a practice mortar bomb comprising explosively releasing compressed fluid contained within the practice mortar bomb via an outlet valve system.
- This system may eliminate the need for using an explosive charge (which may be more expensive and dangerous) during practicing the skill of mortaring.
- FIG. 1 is a cut-away view showing a practice mortar bomb in accordance with an embodiment of the invention
- FIG. 2 is an enlargement of part A of FIG. 1 showing a cross-section of an outlet valve system according to an embodiment of the invention
- FIG. 3 is a cut-away view showing an alternative practice mortar bomb in accordance with an embodiment of the invention.
- FIG. 4 is an enlargement of part A of FIG. 3 showing a cross-section of an outlet valve system according to an embodiment of the invention
- FIG. 5 is a cut-away view showing an alternative practice mortar bomb in accordance with an embodiment of the invention.
- FIG. 6 is an enlargement of part A of FIG. 5 showing a cross-section of an outlet valve system according to an embodiment of the invention.
- a practice mortar bomb is generally provided at 100 .
- Such a practice mortar may be provided in various calibres to facilitate firing from standard mortar tubes (e.g. 51, 60, 81 or 120 mm).
- the practice mortar bomb 100 is 60 mm, but as will be appreciated this is not intended to be limiting.
- the bomb 100 comprises a main body portion 104 positioned intermediate a nose portion 102 and a tail portion 106 .
- the main body portion 104 is substantially ellipsoid in shape and is provided by head element 108 and base element 110 .
- the head and base elements 108 , 110 are releasably engageable using cooperating main body screw threaded regions 112 .
- the base element is provided with an annular rebate 114 on its exterior surface which may be used to receive an obturating ring (not shown).
- the main body portion 104 defines a pressure vessel 116 in the form of a void surrounded by the main body portion 104 walls.
- the head element 108 is shaped to provide an inlet valve system housing 118 in the form of a cylindrical portion, coaxial with the main body 104 and having a reduced diameter.
- an inlet valve system (not shown here for clarity) comprising a one way valve allowing charging of the pressure vessel 116 .
- the base element 110 is shaped to provide a valve seat 120 for an outlet valve system 122 (described in greater detail later with reference to FIG. 2 ).
- the nose portion 102 (which in some embodiments may be a dummy fuse) is substantially conical in shape and has a hollow interior portion 124 to accommodate protruding portions of the inlet valve system.
- the nose portion 102 is releasably engageable with the head element 108 using cooperating nose screw threaded regions 126 .
- the tail portion 106 is substantially cylindrical in shape and has a hollow interior portion 128 in fluid communication with the valve seat 120 .
- the tail portion 106 is provided with a plurality of ports 130 through its sidewall 132 , the ports 130 providing fluid communication between the hollow interior portion 128 and the exterior of the tail portion 106 .
- the tail portion further comprises a plurality of stabilising fins 134 projecting outwards from the tail portion 106 .
- the tail portion 106 has a tail portion through bore 136 which receives a pin 138 passing from the outlet valve system 122 , through the hollow interior portion 128 and through the tail portion through bore 136 .
- the tail portion 106 is releasably engageable with the base element 110 using cooperating tail screw threaded regions 140 .
- the outlet valve system 122 has a valve body 142 engageable with the valve seat 120 .
- the valve body 142 is shown in an engaged position with the valve seat 120 . It will be appreciated however that the valve body 142 is mobile and consequently may also be disengaged from the valve seat 120 by raising the valve body 142 .
- the valve body 142 is substantially cylindrical and has a head end 144 and a valve seat end 146 .
- the head end 144 is provided with a firing valve seat 148 comprising a countersunk region of a valve body through bore 150 which passes through the valve body 142 from the head end 144 to the valve seat end 146 .
- Engaged with the firing valve seat 148 is a firing valve body 152 .
- the firing valve body 152 is shown in an engaged position with the firing valve seat 148 . It will be appreciated however that the firing valve body 152 is mobile and consequently may also be disengaged from the firing valve seat 148 by raising the firing valve body 152 .
- Extending from the firing valve body 152 , through the valve body through bore 150 is the pin 138 .
- the pin 138 has a smaller diameter than the valve body through bore 150 .
- the pin 138 is guided and supported proximate the valve seat end 146 by a pin guide plate 154 .
- the valve seat end 146 has a chamfered peripheral (and is therefore rebated) that extends beyond the valve seat and into a cylinder 156 when the valve seat end 146 is engaged with the valve seat 120 .
- the chamfering provides a biasing surface 158 opposed to the head end 144 of the valve body 142 .
- the cylinder 156 surrounds the valve body 142 in a close fit, supporting movement of the valve body 142 .
- the cylinder and the head end 144 define a chamber 160 .
- the chamber 160 is in fluid communication with the pressure vessel 116 via a cylinder through bore 162 .
- the cylinder 156 and biasing surface 158 define a cavity 164 .
- the cavity 164 is in fluid communication with the interior of the pressure vessel 116 .
- the passages 166 which pass through the cylinder 156 , are further defined by the cylinder 156 and base element 110 walls.
- the fluid gaps 165 have a total cross-sectional area that is considerably less than the total cross-sectional area of the passages 166 .
- the fluid gaps 165 are formed by an increase in the diameter of the cylinder 156 , between the passages 166 and the cavity 164 .
- the practice mortar bomb 100 may be used by someone wishing to practice the skill of firing a mortar and or associated skills. Exemplary use and operation of the practice mortar bomb 100 is now provided with reference to FIGS. 1 and 2 .
- the user first disengages the nose portion 102 using nose screw threaded regions 126 , giving access to the inlet valve system.
- the user then charges the pressure vessel 116 with compressed fluid via the inlet valve system 116 .
- This may for example be achieved via use of a pump or compressor. Any suitable compressed fluid may be used, for example air or nitrogen.
- the pressure vessel 116 is charged to a pressure in accordance with a desired range and the calibre of the practice mortar bomb.
- the pressure vessel of a 60 mm practice mortar bomb 100 might be charged to between 20 and 100 bar, preferably between 35 and 60 bar and more preferably to between 45 and 50 bar.
- Compressed fluid in the pressure vessel 116 is free to pass into chamber 160 , where it impinges on the head end 144 of the valve body 142 with sufficient force to engage the valve seat end 146 of the valve body 142 with the valve seat 120 . This prevents the flow of compressed fluid from the pressure vessel 116 through the outlet valve system 122 .
- Compressed fluid in the pressure vessel 116 is also free to pass through passages 166 and fluid gaps 165 into cavities 164 , where it impinges on the biasing surface 158 .
- This pressure on the biasing surface 158 biases the valve seat end 146 to disengage from the valve seat 120 .
- the net force on the valve body 142 is such that the valve seat end 146 remains engaged with the valve seat 120 . This is due to the relative surface areas of the opposed surfaces (the head end 144 and biasing surface 158 ).
- Compressed fluid in the chamber 160 also impinges on the firing valve body 152 forcing it to engage the firing valve seat 148 . This prevents compressed fluid being discharged from the chamber 160 via the valve body through bore 150 .
- the user selects a nose portion 102 corresponding to the appearance of a particular fuse type, (e.g. detonation fuse, proximity fuse, a mechanical time fuse, a multi-option fuse or a practice fuse) corresponding to a simulated fire mission to be undertaken.
- a particular fuse type e.g. detonation fuse, proximity fuse, a mechanical time fuse, a multi-option fuse or a practice fuse
- the selected nose portion 102 is then engaged using the nose screw threaded regions 126 .
- the practice mortar bomb 100 engages a firing pin in the bottom of the tube.
- the firing pin is received in the tail portion through bore 136 and displaces the pin 138 upwards.
- the pin 138 guided and supported by the tail portion through bore 136 and pin guide plate 154 , disengages the firing valve body 152 from the firing valve seat 148 , moving it upwards.
- the cavity 160 cannot be re-pressurised while the firing valve body 152 is disengaged from the firing valve seat 148 .
- the practice mortar bomb 100 is also suitable for use in mortar tubes that have an externally triggerable firing pin which is activated after the practice mortar bomb 100 has been inserted into the tube.
- the firing pin in the mortar tube is removed from the tail portion through bore 136 .
- the chamber 160 is allowed to re-pressurise via the cylinder through bore 162 and the valve body 142 is forced to engage the valve seat 120 .
- the outlet valve system 122 may be referred to as a pressure balance valve. Further the opposed surfaces may be considered to be locations on which pressure from the compressed fluid may act.
- the practice mortar bomb 200 is similar to the practice mortar bomb 100 except that an alternative outlet valve system 222 is provided.
- the outlet valve system 222 is similar to the outlet valve system 122 , but several modifications have been made.
- the outlet valve system 222 has a valve body 242 engageable with the valve seat 220 .
- the valve body 242 is shown in an engaged position with the valve seat 220 . It will be appreciated however that the valve body 242 is mobile and consequently may also be disengaged from the valve seat 220 by raising the valve body 242 .
- the valve body 242 is substantially cylindrical and has a head end 244 and a valve seat end 246 .
- the head end 244 is provided with a firing valve seat 248 comprising a countersunk region of a valve body through bore 250 , passing through the valve body 242 from the head end 244 to the valve seat end 246 .
- Engaged with the firing valve seat 248 is a firing valve body 252 .
- the firing valve body 252 is shown in an engaged position with the firing valve seat 248 . It will be appreciated however that the firing valve body 252 is mobile and consequently may also be disengaged from the firing valve seat 248 by raising the firing valve body 252 .
- Extending from the firing valve body 252 , through the valve body through bore 250 is a pin 238 .
- the pin 238 has a smaller diameter than the valve body through bore 250 .
- the pin 238 is guided and supported proximate the valve seat end 246 by a pin guide plate 254 .
- the valve seat end 246 has a chamfered peripheral and a rebated portion 255 formed by a reduction in the diameter of the valve body 242 .
- the rebated portion 255 provides a biasing surface 258 opposed to the head end 244 of the valve body 242 .
- a cylinder 256 surrounds the valve body 242 in a close fit, supporting movement of the valve body 242 .
- the cylinder and the head end 244 define a chamber 260 and a spring guide 261 .
- the chamber 260 is in fluid communication with the pressure vessel 216 via a cylinder through bore 262 and a flat 262 a in the firing valve body 252 .
- a spring 263 provided within the spring guide is in contact with the firing valve body 252 and biases it towards the firing valve seat 248 .
- the cylinder 256 and biasing surface 258 define a cavity 264 .
- the cavity 264 is in fluid communication with the interior of the pressure vessel 216 .
- the passages 266 which pass through the cylinder 256 , are further defined by the cylinder 256 and base element 210 walls.
- the spring 263 helps to prevent leakage of fluid through the valve body through bore 250 before firing of the practice mortar bomb.
- the spring also assists with re-engaging the firing valve body 252 with the firing valve seat 248 once explosive release of compressed fluid has occurred, in order that the outlet valve system 222 is re-set and a positive pressure is maintained in the pressure vessel 216 .
- the arrangement of the rebated portion 255 which increases the size of the cavity 264 , means that compressed fluid may be released more quickly than with the arrangement of FIG. 2 .
- the practice mortar bomb 300 is similar to the practice mortar bomb 200 except that for a number of features.
- the exterior wall of a spring guide 361 is provided with a spanner/wrench formation 370 (in this case hexagonal) to facilitate screwing and unscrewing of a cylinder 356 to a base element 310 during assembly/disassembly of the practice mortar bomb 300 .
- a further modification of the practice mortar bomb 300 is that a valve body 342 is provided with a seal 372 (in this case an O-ring) to improve the seal between the valve body 342 and the cylinder 356 . Further a countersunk region of a valve body through bore 350 is curved so as a firing valve seat 348 in a head end 344 of the valve body 342 cooperates in a close fit with a curved engagement surface 374 of a firing valve body 352 . This curved arrangement (which may be hemispherical) improved seating of the firing valve body.
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- General Engineering & Computer Science (AREA)
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- Combustion & Propulsion (AREA)
- Filling Or Discharging Of Gas Storage Vessels (AREA)
Abstract
A practice mortar bomb comprising a pressure vessel and an outlet valve system, the pressure vessel being arranged in use to contain compressed fluid and the outlet valve system being arranged in use to allow explosive release of the compressed fluid from the pressure vessel upon activation of the valve system by a firing pin in a mortar tube.
Description
- The present invention relates to practice ammunition rounds. More specifically the invention relates to practice mortar bombs, a method of explosively releasing compressed fluid from a pressure vessel via an outlet valve system, a method of firing a practice mortar bomb, a method of propelling a practice mortar bomb and a kit of parts.
- A mortar is a weapon system typically used by infantrymen to provide indirect fire. Mortars are based around a mortar tube (the orientation of which is adjustable for aiming) down which is dropped a mortar bomb. Mortar bombs have a tail portion containing explosive propellant which is initiated by a firing pin at the bottom of the mortar tube. The resulting explosion combined with the tight fit of the bomb within the tube propels the bomb from the mortar barrel.
- As will be appreciated it is highly desirable that operators should be given the opportunity of practicing with mortars before they are called upon to use them in combat. There are many skills to learn, including transporting, assembling, aiming and firing the mortar. Beyond this there are more specialised proficiencies such as firing patterns and use of different bomb types (e.g. smoke, illumination and high explosive).
- In practicing these skills it is in many cases desirable to actually fire the weapon or at least to re-create actual firing of the weapon as accurately as possible. As will be appreciated there are however several draw-backs to practicing with a real mortar and live ammunition. A live mortar bomb is very expensive and is not re-usable. Firing live rounds also requires a large area (which may be quickly damaged if sufficient practice is undertaken). Further the use of live ammunition gives rise to the need for a great deal of attention to be given to safety, not only in use but also in procurement, storage and transport. This is time consuming and expensive.
- As a consequence of the above it is normal for mortar teams to have very limited practice using live ammunition. In substituting for this it is known to practice by ‘going through the motions’ without actually firing a round. This is very limited in terms of the experience that it can provide and further is often considered boring and ineffective by mortar teams. Computer simulations are also used which can provide a more useful substitute for certain aspects such as aiming. Nonetheless there is still a need for a cheaper, safer method of more realistically practicing firing a mortar.
- According to a first aspect of the invention a practice mortar bomb is provided comprising optionally a pressure vessel and optionally an outlet valve system, the pressure vessel being arranged in use to optionally contain compressed fluid and the outlet valve system being arranged in use to optionally allow explosive release of the compressed fluid from the pressure vessel optionally upon activation of the valve system by a firing pin in a mortar tube. This practice mortar bomb may provide a relatively safe, inexpensive and yet realistic way of practicing the firing of a mortar.
- In some embodiments the practice mortar bomb further comprises an inlet valve system arranged in use to allow charging of the pressure vessel with fluid such that the fluid is compressed within the pressure vessel. The inlet valve system may provide a convenient way of filling the pressure vessel and may also allow re-use of the mortar bomb by re-filling the pressure vessel via the inlet valve system. This may make repeated practice considerably less expensive.
- In some embodiments the inlet valve system comprises a one-way valve allowing storage of the compressed fluid in the pressure vessel once charged. The one-way valve may offer a convenient way of allowing filling of the pressure vessel and the retention of compressed fluid for an extended period thereafter.
- In some embodiments the inlet valve system is positioned at a head end of the pressure vessel. Positioning of the inlet valve system in this way may allow for a reduced impact on the appearance and performance of the practice mortar bomb so as it better resembles a standard mortar bomb in appearance and performance.
- In some embodiments the outlet valve system is positioned at a base end of the pressure vessel. This may lead to a more direct release of compressed fluid in the desired direction for firing of the bomb.
- In some embodiments the outlet valve mechanism comprises a valve seat and valve body, the valve body being mobile such that in use a valve seat end of the valve body is engageable with the valve seat to block the flow of fluid from the pressure vessel, and is disengageable from the valve seat to allow the flow of fluid from the pressure vessel.
- In some embodiments the outlet valve system is a pressure balance valve, being arranged such that in use, compressed fluid from the interior of the pressure vessel impinges on at least two opposed surfaces of the valve body, the resulting net force being towards the valve seat until the outlet valve system is activated, whereupon the net force is away from the valve seat. The pressure balance valve may be a particularly effective way of allowing explosive release of compressed fluid, as the compressed fluid itself may be used to move the valve body away from the valve seat and so open the outlet valve system. This may lead to a very rapid opening of the outlet valve system. Further the pressure balance valve may allow re-setting of the outlet valve system after explosive fluid discharge.
- In some embodiments a first of the opposed surfaces is a head end of the valve body and a second of the opposed surfaces, opposed to the first is a biasing surface proximate the valve seat end of the valve body.
- In some embodiments the outlet valve system further comprises a chamber arranged such that in use, compressed fluid in the chamber impinges on the head end of the valve body with sufficient force to cause engagement of the valve seat end of the valve body with the valve seat. The chamber may provide a convenient method of allowing compressed fluid to impinge on the head end, while also isolating (at least to an extent) the fluid in the chamber from fluid in the pressure vessel. This may mean that through discharging the chamber, at least some of the force biasing the valve body towards the valve seat may be removed.
- In some embodiments the practice mortar bomb is arranged such that in use, activation of the outlet valve system leads to the release of compressed fluid from the chamber at a faster rate than it is replenished, such that the force biasing the valve body towards the valve seat is reduced and the net force on the valve body is reversed so as it is away from the valve seat. This may allow for rapid opening of the outlet valve system to permit explosive release of compressed fluid from the pressure vessel.
- In some embodiments release of the compressed fluid from the chamber is controlled by a firing valve, operated in use directly or indirectly by a firing pin in a mortar tube. This may allow the firing pin in a standard mortar tube to initiate firing of the practice mortar bomb. In this way a specialist mortar tube may not be required, potentially increasing the realism of practice.
- In some embodiments the outlet valve system is arranged such that in use it re-sets before all of the compressed fluid has been explosively released from the pressure vessel. In this way a positive pressure may be maintained in the pressure vessel, helping to prevent the ingress of foreign material such as dust, sand and/or water into the practice mortar bomb. This may be particularly advantageous in view of the fact that the practice mortar bomb may dig into the earth on landing (at least to an extent).
- In some embodiments the outlet valve mechanism further comprises a cylinder in which the valve body moves and is contained in a close fit. The cylinder may be an effective way of guiding movement of the valve body and of creating the chamber adjacent the head end of the valve body.
- In some embodiments the chamber is defined by the cylinder and the head end of the valve body.
- In some embodiments the cylinder has one or more cylinder through bores arranged so that the interior of the pressure vessel is in fluid communication with the chamber, such that in use pressurised fluid passes from the pressure vessel into the chamber. The cylinder through bores may therefore allow charging of the chamber from compressed fluid in the pressure vessel, in order that the valve body may be biased towards the valve seat.
- In some embodiments a region proximate the valve seat end of the valve body is provided with one or more rebated portions, each creating a cavity between the cylinder and the valve body. The cavities may assist in creating one or more surfaces for implementation of the pressure balance valve.
- In some embodiments the rebated portions create the biasing surface of the valve body, arranged such that at least a component of a force applied towards the biasing surface would act to bias the valve body away from the valve seat.
- In some embodiments the rebated portions comprise chamfering of the valve seat end of the valve body that extends beyond the valve seat and into the cylinder when the valve seat end of the valve body is engaged with the valve seat. The chamfering may assist in locating of the valve seat end of the valve body within the valve seat, and it may conveniently also provide the biasing surface.
- In some embodiments one or more passages is provided passing through the cylinder wall allowing fluid communication between the interior of the pressure vessel and the cavities. This may allow fluid pressure to be applied to the biasing surfaces from the pressure vessel for implementing the fluid balance valve.
- In some embodiments fluid gaps are provided intermediate the passages and cavities, created by an increase in the diameter of the cylinder between the passages and the cavities. Where these fluid gaps have a relatively narrow diameter in comparison to the passages, the fluid gaps may be sufficient to cause the valve body to rapidly disengage the valve seat. Thereafter as the valve body clears the passages fluid may be explosively released via the passages which may be of a relatively large diameter.
- In some embodiments the head end of the valve body has a sufficient surface area such that if the same pressure were applied to the head end of the valve body and the biasing surface, the net force on the valve body would cause the valve seat end of the valve body to engage with the valve seat. This may ensure that the default condition of the outlet valve system is closed so as to prevent discharge of fluid from the pressure vessel until compressed fluid is discharged from the chamber.
- In some embodiments the valve body has a valve body through bore passing from the head end of the valve body to the valve seat end of the valve body. This may provide a convenient path for discharging compressed fluid from the chamber when the outlet valve system is activated.
- In some embodiments the head end of the valve body through bore is provided with a firing valve seat.
- In some embodiments a firing valve body is provided which, when there is compressed fluid in the chamber, is biased by the compressed fluid into engagement with the firing valve seat. This may ensure that the default condition of the firing valve is closed, preventing the discharge of fluid from the chamber (and so the opening of the outlet valve system) until the valve is activated.
- As will be appreciated in some embodiments a spring may be provided to increase the force biasing the firing valve body into engagement with the valve seat.
- In some embodiments a pin of smaller diameter than the valve body through bore extends from the firing valve body through the valve body through bore. This pin may provide a convenient method of activating the outlet valve system, in that pushing on the pin may open the firing valve, by raising the firing valve body from the firing valve seat.
- In some embodiments the pin is arranged to force the firing valve away from the firing valve seat when an end of the pin is impacted by a firing pin in a mortar tube. The pin may therefore act as an intermediary between the firing pin of the mortar tube and the firing valve body. It this way it may be possible to use a conventional mortar tube.
- In some embodiments the cylinder through bore and valve body through bore are arranged such that greater quantities of fluid at a given pressure are passable through the valve body through bore than through the cylinder through bore in a given time. This may ensure that for as long as the firing pin of the mortar tube is keeping the firing valve open, the chamber cannot re-charge with pressurised fluid. This may mean that the outlet valve system will open and remain open, at least until the bomb is fired.
- In some embodiments the practice mortar bomb further comprises a dummy fuse nose portion. The nose portion may mean that the practice mortar bomb is more like a standard mortar bomb, i.e. in terms of appearance and/or aerodynamic profile and/or shape and/or size and/or weight, thus potentially making its use in practice more realistic.
- In some embodiments the nose portion simulates a known mortar bomb fuse type. This may make the practice mortar bomb more like a standard mortar bomb, i.e. in terms of appearance and/or aerodynamic profile and/or shape and/or size and/or weight, thus potentially making its use in practice more realistic. The fuse may for example simulate a point detonation fuse, a proximity fuse, a mechanical time fuse, a multi-option fuse or a practice fuse.
- In some embodiments the nose portion is releasably engageable with the bomb. This may allow the nose portion to be interchangeable with alternatives simulating different dummy fuses, depending on the practice to be undertaken.
- In some embodiments the nose portion provides a cap over the inlet valve system. This may serve to protect the nose portion especially during impact of the practice mortar bomb on landing.
- In some embodiments the bomb further comprises a hollow tail portion, the interior of the tail portion being in fluid communication with the pressure vessel when the outlet valve system is open. The tail portion may allow more accurate simulation of the appearance of a standard mortar bomb. Further the tail portion may receive the explosively released fluid from the outlet valve system, allowing it to be directed.
- In some embodiments the tail portion comprises one or more ports allowing fluid communication between its interior and exterior. The ports may be used to direct explosively released fluid into a mortar tube below the level of the pressure vessel.
- In some embodiments the tail portion has a tail portion through bore arranged in use to receive at least one of the pin and, in use the firing pin of a mortar tube. The tail portion through bore may help to ensure that the firing pin of the mortar tube is properly aligned and received by the practice mortar bomb in order that it may displace the pin.
- In some embodiments the pin is of sufficient length and aligned with the tail portion through bore so as a firing pin of a mortar entering the tail portion through bore will impact and push against the pin so as to push the firing valve body away from the firing valve seat. This may help to ensure a proper contact between the pin and firing pin of a mortar tube.
- In some embodiments the practice mortar bomb has an overfill pressure release valve. This may be an effective safety feature against over charging of the pressure vessel.
- According to a second aspect of the invention there is provided a kit of parts comprising optionally one or more pressure vessels for practice mortar bombs in accordance with the first aspect and optionally one or more of the following:
-
- one or more nose portions optionally of various designs to simulate different known mortar bomb fuse types,
- one or more tail portions,
- one or more pumps.
Such kits may be convenient especially when practice is being undertaken. For example a mortar team may select different fuses when practicing different fire missions and may re-charge the pressure vessel on the practice range using the pump.
- According to a third aspect of the invention a method of explosively releasing compressed fluid from a pressure vessel via an outlet valve system is provided, the pressure vessel and outlet valve system being provided in a practice mortar bomb, comprising the steps of:
-
- exposing a valve body of the valve system to pressure from the compressed fluid acting in at least two different locations so as to bias the valve body both towards and away from a valve seat, with the net force being towards the valve seat,
- activating the valve to release compressed fluid from at least one of the location to reduce the force acting to bias the valve body towards the valve seat so that the net force is away from the valve seat.
This method may allow rapid release of the compressed fluid in a manner sufficient to propel the practice mortar bomb a desired distance.
- In some embodiments the method further comprises re-charging the location from which compressed fluid has been released so as the net force is again towards the valve seat. This may allow the practice mortar bomb to be re-used by re-charging the pressure vessel.
- According to a fourth aspect of the invention a method of firing a practice mortar bomb is provided, the practice mortar bomb comprising optionally a pressure vessel and optionally an outlet valve system optionally arranged upon activation to explosively release at least a portion of a compressed air reservoir in the pressure vessel, the method comprising the steps of:
-
- optionally charging the pressure vessel with compressed fluid, and
- optionally dropping the mortar bomb down a mortar tube.
This method may be more realistic for those practicing the skill of mortaring than going through the motions without actually firing a mortar bomb. Further the method may be safer and relatively inexpensive in comparison to using a real mortar bomb.
- In some embodiments the method further comprises collecting the practice mortar bomb for optional re-use. This may improve cost effectiveness of mortar practice.
- In some embodiment the method further comprises selecting a head portion for attachment to the practice mortar bomb before it is fired. This may allow a mortar user to more accurately simulate performing different fire missions by selecting different dummy fuse head portions.
- According to a fifth aspect of the invention a method of propelling a practice mortar bomb is provided comprising explosively releasing compressed fluid contained within the practice mortar bomb via an outlet valve system. This system may eliminate the need for using an explosive charge (which may be more expensive and dangerous) during practicing the skill of mortaring.
- The skilled person will appreciate that a feature described in relation to any one of the above aspects of the invention may be applied mutatis mutandis to any other aspect of the invention.
- Embodiments of the invention will now be described by way of example only, with reference to the accompanying Figures, in which:
-
FIG. 1 is a cut-away view showing a practice mortar bomb in accordance with an embodiment of the invention; -
FIG. 2 is an enlargement of part A ofFIG. 1 showing a cross-section of an outlet valve system according to an embodiment of the invention; -
FIG. 3 is a cut-away view showing an alternative practice mortar bomb in accordance with an embodiment of the invention; -
FIG. 4 is an enlargement of part A ofFIG. 3 showing a cross-section of an outlet valve system according to an embodiment of the invention; -
FIG. 5 is a cut-away view showing an alternative practice mortar bomb in accordance with an embodiment of the invention; and -
FIG. 6 is an enlargement of part A ofFIG. 5 showing a cross-section of an outlet valve system according to an embodiment of the invention. - Referring first to
FIG. 1 a practice mortar bomb is generally provided at 100. Such a practice mortar may be provided in various calibres to facilitate firing from standard mortar tubes (e.g. 51, 60, 81 or 120 mm). Thepractice mortar bomb 100 is 60 mm, but as will be appreciated this is not intended to be limiting. - The
bomb 100 comprises amain body portion 104 positioned intermediate anose portion 102 and atail portion 106. - The
main body portion 104 is substantially ellipsoid in shape and is provided byhead element 108 andbase element 110. The head andbase elements regions 112. The base element is provided with anannular rebate 114 on its exterior surface which may be used to receive an obturating ring (not shown). - The
main body portion 104 defines apressure vessel 116 in the form of a void surrounded by themain body portion 104 walls. - At a head end of the
pressure vessel 116 thehead element 108 is shaped to provide an inletvalve system housing 118 in the form of a cylindrical portion, coaxial with themain body 104 and having a reduced diameter. In the inletvalve system housing 118 is positioned an inlet valve system (not shown here for clarity) comprising a one way valve allowing charging of thepressure vessel 116. - At a base end of the
pressure vessel 116 thebase element 110 is shaped to provide avalve seat 120 for an outlet valve system 122 (described in greater detail later with reference toFIG. 2 ). - The nose portion 102 (which in some embodiments may be a dummy fuse) is substantially conical in shape and has a hollow
interior portion 124 to accommodate protruding portions of the inlet valve system. Thenose portion 102 is releasably engageable with thehead element 108 using cooperating nose screw threadedregions 126. - The
tail portion 106 is substantially cylindrical in shape and has a hollowinterior portion 128 in fluid communication with thevalve seat 120. Thetail portion 106 is provided with a plurality ofports 130 through itssidewall 132, theports 130 providing fluid communication between the hollowinterior portion 128 and the exterior of thetail portion 106. The tail portion further comprises a plurality of stabilisingfins 134 projecting outwards from thetail portion 106. Thetail portion 106 has a tail portion throughbore 136 which receives apin 138 passing from theoutlet valve system 122, through the hollowinterior portion 128 and through the tail portion throughbore 136. Thetail portion 106 is releasably engageable with thebase element 110 using cooperating tail screw threadedregions 140. - Referring now to
FIG. 2 the parts of theoutlet valve system 122 are described. Theoutlet valve system 122 has avalve body 142 engageable with thevalve seat 120. InFIG. 2 thevalve body 142 is shown in an engaged position with thevalve seat 120. It will be appreciated however that thevalve body 142 is mobile and consequently may also be disengaged from thevalve seat 120 by raising thevalve body 142. - The
valve body 142 is substantially cylindrical and has ahead end 144 and avalve seat end 146. - The
head end 144 is provided with a firingvalve seat 148 comprising a countersunk region of a valve body throughbore 150 which passes through thevalve body 142 from thehead end 144 to thevalve seat end 146. Engaged with the firingvalve seat 148 is a firingvalve body 152. InFIG. 2 thefiring valve body 152 is shown in an engaged position with the firingvalve seat 148. It will be appreciated however that the firingvalve body 152 is mobile and consequently may also be disengaged from the firingvalve seat 148 by raising the firingvalve body 152. Extending from the firingvalve body 152, through the valve body throughbore 150 is thepin 138. Thepin 138 has a smaller diameter than the valve body throughbore 150. Thepin 138 is guided and supported proximate thevalve seat end 146 by apin guide plate 154. - The
valve seat end 146 has a chamfered peripheral (and is therefore rebated) that extends beyond the valve seat and into acylinder 156 when thevalve seat end 146 is engaged with thevalve seat 120. The chamfering provides a biasingsurface 158 opposed to thehead end 144 of thevalve body 142. - The
cylinder 156 surrounds thevalve body 142 in a close fit, supporting movement of thevalve body 142. The cylinder and thehead end 144 define achamber 160. Thechamber 160 is in fluid communication with thepressure vessel 116 via a cylinder throughbore 162. - The
cylinder 156 and biasingsurface 158 define acavity 164. As a consequence offluid gaps 165 andpassages 166, thecavity 164 is in fluid communication with the interior of thepressure vessel 116. Thepassages 166, which pass through thecylinder 156, are further defined by thecylinder 156 andbase element 110 walls. Thefluid gaps 165 have a total cross-sectional area that is considerably less than the total cross-sectional area of thepassages 166. Thefluid gaps 165 are formed by an increase in the diameter of thecylinder 156, between thepassages 166 and thecavity 164. - In use the
practice mortar bomb 100 may be used by someone wishing to practice the skill of firing a mortar and or associated skills. Exemplary use and operation of thepractice mortar bomb 100 is now provided with reference toFIGS. 1 and 2 . - The user first disengages the
nose portion 102 using nose screw threadedregions 126, giving access to the inlet valve system. The user then charges thepressure vessel 116 with compressed fluid via theinlet valve system 116. This may for example be achieved via use of a pump or compressor. Any suitable compressed fluid may be used, for example air or nitrogen. Thepressure vessel 116 is charged to a pressure in accordance with a desired range and the calibre of the practice mortar bomb. By way of example the pressure vessel of a 60 mmpractice mortar bomb 100 might be charged to between 20 and 100 bar, preferably between 35 and 60 bar and more preferably to between 45 and 50 bar. - Compressed fluid in the
pressure vessel 116 is free to pass intochamber 160, where it impinges on thehead end 144 of thevalve body 142 with sufficient force to engage thevalve seat end 146 of thevalve body 142 with thevalve seat 120. This prevents the flow of compressed fluid from thepressure vessel 116 through theoutlet valve system 122. - Compressed fluid in the
pressure vessel 116 is also free to pass throughpassages 166 andfluid gaps 165 intocavities 164, where it impinges on the biasingsurface 158. This pressure on the biasingsurface 158 biases thevalve seat end 146 to disengage from thevalve seat 120. However the net force on thevalve body 142 is such that thevalve seat end 146 remains engaged with thevalve seat 120. This is due to the relative surface areas of the opposed surfaces (thehead end 144 and biasing surface 158). - Compressed fluid in the
chamber 160 also impinges on the firingvalve body 152 forcing it to engage the firingvalve seat 148. This prevents compressed fluid being discharged from thechamber 160 via the valve body throughbore 150. - The user then selects a
nose portion 102 corresponding to the appearance of a particular fuse type, (e.g. detonation fuse, proximity fuse, a mechanical time fuse, a multi-option fuse or a practice fuse) corresponding to a simulated fire mission to be undertaken. The selectednose portion 102 is then engaged using the nose screw threadedregions 126. - The user then drops the
practice mortar bomb 100 down a mortar tube (not shown) in which thepractice mortar bomb 100 is a tight fit. When thepractice mortar bomb 100 reaches the bottom of the mortar tube it engages a firing pin in the bottom of the tube. The firing pin is received in the tail portion throughbore 136 and displaces thepin 138 upwards. Thepin 138, guided and supported by the tail portion throughbore 136 and pinguide plate 154, disengages the firingvalve body 152 from the firingvalve seat 148, moving it upwards. This allows compressed fluid in thechamber 160 to rapidly discharge from thechamber 160 via the fluid body throughbore 136, hollowinterior portion 128 and plurality ofports 130. Further due to the relative diameters of the cylinder through bore 162 (smaller) and fluid body through bore 136 (larger), thecavity 160 cannot be re-pressurised while the firingvalve body 152 is disengaged from the firingvalve seat 148. - The
practice mortar bomb 100 is also suitable for use in mortar tubes that have an externally triggerable firing pin which is activated after thepractice mortar bomb 100 has been inserted into the tube. - As a consequence of the drop in pressure in the
chamber 160, compressed fluid impinging on the biasingsurface 158 causes a reversal in the net force on thevalve body 142, forcing thevalve body 142 upwards so as thevalve seat end 146 disengages with thevalve seat 120. As thevalve body 142 moves upwards thevalve seat end 146 passes thepassages 166, which due to their large diameter allow rapid discharge of the compressed fluid from thepressure vessel 116 via the hollowinterior portion 128 and plurality ofports 130. This explosive release of compressed fluid rapidly fills the area of the mortar tube between the practice mortar bomb and the tube. Due to the tight fit of thepractice mortar bomb 100 within the mortar tube, and action of an obturating ring (not shown) to create an enhanced seal, the released compressed air propels thepractice mortar bomb 100 from the mortar tube. - As the
practice mortar bomb 100 is fired the firing pin in the mortar tube is removed from the tail portion throughbore 136. This leaves thepin 138 free to return to its original position and the firingvalve body 144 to engage with the firingvalve seat 148 under the influence of remaining compressed gas in thechamber 160. In this condition thechamber 160 is allowed to re-pressurise via the cylinder throughbore 162 and thevalve body 142 is forced to engage thevalve seat 120. This ensures that as thepractice mortar bomb 100 is fired, compressed fluid remaining in thepressure vessel 116 is retained, meaning that a positive pressure is maintained within thepressure vessel 116. This may help to prevent the ingress of foreign material into thepractice mortar bomb 100. Further it means that the valve is re-set and ready for re-use of the practice mortar bomb. - In view of the influence on the position of the
valve body 142 exerted by the compressed fluid acting on the opposed surfaces (head end 144 and biasing surface 158) theoutlet valve system 122 may be referred to as a pressure balance valve. Further the opposed surfaces may be considered to be locations on which pressure from the compressed fluid may act. - Referring now to
FIGS. 3 and 4 an alternative practice mortar bomb is generally provided at 200. Thepractice mortar bomb 200 is similar to thepractice mortar bomb 100 except that an alternativeoutlet valve system 222 is provided. - The
outlet valve system 222 is similar to theoutlet valve system 122, but several modifications have been made. - The
outlet valve system 222 has avalve body 242 engageable with thevalve seat 220. InFIG. 4 thevalve body 242 is shown in an engaged position with thevalve seat 220. It will be appreciated however that thevalve body 242 is mobile and consequently may also be disengaged from thevalve seat 220 by raising thevalve body 242. - The
valve body 242 is substantially cylindrical and has ahead end 244 and avalve seat end 246. - The
head end 244 is provided with a firingvalve seat 248 comprising a countersunk region of a valve body throughbore 250, passing through thevalve body 242 from thehead end 244 to thevalve seat end 246. Engaged with the firingvalve seat 248 is a firingvalve body 252. InFIG. 4 thefiring valve body 252 is shown in an engaged position with the firingvalve seat 248. It will be appreciated however that the firingvalve body 252 is mobile and consequently may also be disengaged from the firingvalve seat 248 by raising the firingvalve body 252. Extending from the firingvalve body 252, through the valve body throughbore 250 is apin 238. Thepin 238 has a smaller diameter than the valve body throughbore 250. Thepin 238 is guided and supported proximate thevalve seat end 246 by apin guide plate 254. - The
valve seat end 246 has a chamfered peripheral and a rebatedportion 255 formed by a reduction in the diameter of thevalve body 242. The rebatedportion 255 provides a biasingsurface 258 opposed to thehead end 244 of thevalve body 242. - A
cylinder 256 surrounds thevalve body 242 in a close fit, supporting movement of thevalve body 242. The cylinder and thehead end 244 define achamber 260 and aspring guide 261. Thechamber 260 is in fluid communication with thepressure vessel 216 via a cylinder throughbore 262 and a flat 262 a in the firingvalve body 252. Aspring 263 provided within the spring guide is in contact with the firingvalve body 252 and biases it towards the firingvalve seat 248. - The
cylinder 256 and biasingsurface 258 define acavity 264. As a consequence ofpassages 266, thecavity 264 is in fluid communication with the interior of thepressure vessel 216. Thepassages 266, which pass through thecylinder 256, are further defined by thecylinder 256 andbase element 210 walls. - In the embodiment of
FIGS. 3 and 4 thespring 263 helps to prevent leakage of fluid through the valve body throughbore 250 before firing of the practice mortar bomb. The spring also assists with re-engaging the firingvalve body 252 with the firingvalve seat 248 once explosive release of compressed fluid has occurred, in order that theoutlet valve system 222 is re-set and a positive pressure is maintained in thepressure vessel 216. Further the arrangement of the rebatedportion 255, which increases the size of thecavity 264, means that compressed fluid may be released more quickly than with the arrangement ofFIG. 2 . - Referring now to
FIGS. 5 and 6 an alternative practice mortar bomb is generally provided at 300. Thepractice mortar bomb 300 is similar to thepractice mortar bomb 200 except that for a number of features. - The exterior wall of a
spring guide 361 is provided with a spanner/wrench formation 370 (in this case hexagonal) to facilitate screwing and unscrewing of acylinder 356 to abase element 310 during assembly/disassembly of thepractice mortar bomb 300. - A further modification of the
practice mortar bomb 300 is that avalve body 342 is provided with a seal 372 (in this case an O-ring) to improve the seal between thevalve body 342 and thecylinder 356. Further a countersunk region of a valve body throughbore 350 is curved so as a firingvalve seat 348 in ahead end 344 of thevalve body 342 cooperates in a close fit with acurved engagement surface 374 of a firingvalve body 352. This curved arrangement (which may be hemispherical) improved seating of the firing valve body. - It will be further noted that in the
FIGS. 5 and 6 embodiments no pin guide plate is provided, which highlights that this feature is optional. - It will be understood that the invention is not limited to the embodiments above-described and various modifications and improvements can be made without departing from the various concepts described herein. Any of the features may be employed separately or in combination with any other features and the invention extends to and includes all combinations and sub-combinations of one or more features described herein in any form of practice mortar bomb.
Claims (21)
1. A practice mortar bomb comprising a pressure vessel and an outlet valve system, the pressure vessel being arranged in use to contain compressed fluid and the outlet valve system being arranged in use to allow explosive release of the compressed fluid from the pressure vessel upon activation of the valve system by a firing pin in a mortar tube.
2. A practice mortar bomb according to claim 1 , further comprising an inlet valve system arranged in use to allow charging of the pressure vessel with fluid such that the fluid is compressed within the pressure vessel.
3. A practice mortar bomb according to claim 1 , where the outlet valve mechanism comprises a valve seat and valve body, the valve body being mobile such that in use a valve seat end of the valve body is engageable with the valve seat to block the flow of fluid from the pressure vessel, and is disengageable from the valve seat to allow the flow of fluid from the pressure vessel.
4. A practice mortar bomb according to claim 3 , where the outlet valve system is a pressure balance valve, arranged such that in use, compressed fluid from the interior of the pressure vessel impinges on at least two opposed surfaces of the valve body, the resulting net force being towards the valve seat until the outlet valve system is activated, whereupon the net force is away from the valve seat.
5. A practice mortar bomb according to claim 4 , where the outlet valve system further comprises a chamber arranged such that in use, compressed fluid in the chamber impinges on a head end of the valve body with sufficient force to cause engagement of the valve seat end of the valve body with the valve seat.
6. A practice mortar bomb according to claim 5 , arranged such that in use, activation of the outlet valve system leads to the release of compressed fluid from the chamber at a faster rate than it is replenished, such that the force biasing the valve body towards the valve seat is reduced and the net force on the valve body is reversed so as it is away from the valve seat.
7. A practice mortar bomb according to claim 6 , where release of the compressed fluid from the chamber is controlled by a firing valve, operated in use directly or indirectly by a firing pin in a mortar tube.
8. A practice mortar bomb according to claim 5 , where the outlet valve mechanism further comprises a cylinder and wherein the chamber is defined by the cylinder and the head end of the valve body.
9. A practice mortar bomb according to claim 8 , where the cylinder has at least one cylinder through bore arranged so that the interior of the pressure vessel is in fluid communication with the chamber, such that in use pressurised fluid passes from the pressure vessel into the chamber.
10. A practice mortar bomb according to claim 3 , where a region proximate the valve seat end of the valve body is provided with at least one rebated portion, where each rebated portion creates a cavity between the cylinder and the valve body.
11. A practice mortar bomb according to claim 10 , where the at least one rebate portion creates at least one biasing surface of the valve body, arranged such that at least a component of a force applied towards the biasing surface would act to bias the valve body away from the valve seat.
12. A practice mortar bomb according to claim 3 , where the valve body has a valve body through bore passing from the head end of the valve body to the valve seat end of the valve body.
13. A practice mortar bomb according to claim 12 , where the head end of the valve body through bore is provided with a firing valve seat.
14. A practice mortar bomb according to claim 13 , where a firing valve body is provided which, when there is compressed fluid in the chamber, is biased by the compressed fluid into engagement with the firing valve seat.
15. A practice mortar bomb according to claim 12 , where a pin of smaller diameter than the valve body through bore extends from the firing valve body through the valve body through bore.
16. A practice mortar bomb according to claim 15 , where the pin is arranged to force the firing valve away from the firing valve seat when an end of the pin is impacted by a firing pin in a mortar tube.
17. A practice mortar bomb according to claim 1 , where the bomb further comprises a hollow tail portion, the interior of the tail portion being in fluid communication with the pressure vessel when the outlet valve system is open.
18. A practice mortar bomb according to claim 17 , where the tail portion comprises at least one port allowing fluid communication between its interior and exterior.
19. A practice mortar bomb according to claim 17 , where the tail portion has a tail portion through bore arranged in use to receive at least one of the pin and, in use the firing pin of a mortar tube.
20. A kit of parts comprising one or more pressure vessels for practice mortar bombs in accordance with claim 1 and one or more of the following:
one or more nose portions of various designs to simulate different known mortar bomb fuse types,
one or more tail portions,
one or more pumps.
21. A method of firing a practice mortar bomb, the practice mortar bomb comprising a pressure vessel and an outlet valve system arranged upon activation to explosively release at least a portion of a compressed air reservoir in the pressure vessel, the method comprising the steps of:
charging the pressure vessel with compressed fluid, and
dropping the mortar bomb down a mortar tube.
Priority Applications (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
GB201305319A GB2498127B (en) | 2012-05-29 | 2013-03-22 | Practice projectile |
PCT/GB2013/051424 WO2013179030A1 (en) | 2012-05-29 | 2013-05-29 | Practice mortar projectile |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
GBGB1209537.8 | 2012-05-29 | ||
GB201209537A GB201209537D0 (en) | 2012-05-29 | 2012-05-29 | Practice projectile |
Publications (1)
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US20150083010A1 true US20150083010A1 (en) | 2015-03-26 |
Family
ID=46546128
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
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US13/611,654 Abandoned US20150083010A1 (en) | 2012-05-29 | 2012-09-12 | Practice Projectile |
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US (1) | US20150083010A1 (en) |
GB (1) | GB201209537D0 (en) |
Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20170138712A1 (en) * | 2015-11-12 | 2017-05-18 | Randy S. Teig | Mechanically adaptable projectile and method of manufacturing the same |
WO2018085948A1 (en) * | 2016-11-11 | 2018-05-17 | Mil-Sim-Fx International Inc. | Cartridge for military training device, activation device for cartridge, cartridge kit, and related methods |
US10119780B1 (en) * | 2018-01-12 | 2018-11-06 | David Wayne Bergeron | Light gas gun projectile |
US20180321021A1 (en) * | 2015-11-12 | 2018-11-08 | Randy S. Teig | Mechanically adaptable projectile and method of manufacturing the same |
-
2012
- 2012-05-29 GB GB201209537A patent/GB201209537D0/en not_active Ceased
- 2012-09-12 US US13/611,654 patent/US20150083010A1/en not_active Abandoned
Cited By (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20170138712A1 (en) * | 2015-11-12 | 2017-05-18 | Randy S. Teig | Mechanically adaptable projectile and method of manufacturing the same |
US20180321021A1 (en) * | 2015-11-12 | 2018-11-08 | Randy S. Teig | Mechanically adaptable projectile and method of manufacturing the same |
WO2018085948A1 (en) * | 2016-11-11 | 2018-05-17 | Mil-Sim-Fx International Inc. | Cartridge for military training device, activation device for cartridge, cartridge kit, and related methods |
US11421969B2 (en) | 2016-11-11 | 2022-08-23 | Mil-Sim-Fx International Inc. | Cartridge for military training device, activation device for cartridge, cartridge kit, and related methods |
US10119780B1 (en) * | 2018-01-12 | 2018-11-06 | David Wayne Bergeron | Light gas gun projectile |
Also Published As
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GB201209537D0 (en) | 2012-07-11 |
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