EP4088083B1 - Improvement relating to projectile cartridge obturators and wads and cartridges employing such - Google Patents
Improvement relating to projectile cartridge obturators and wads and cartridges employing such Download PDFInfo
- Publication number
- EP4088083B1 EP4088083B1 EP20828105.5A EP20828105A EP4088083B1 EP 4088083 B1 EP4088083 B1 EP 4088083B1 EP 20828105 A EP20828105 A EP 20828105A EP 4088083 B1 EP4088083 B1 EP 4088083B1
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- EP
- European Patent Office
- Prior art keywords
- obturator
- cartridge
- skirt portion
- seal
- annular skirt
- Prior art date
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- 239000000835 fiber Substances 0.000 claims description 25
- 239000003721 gunpowder Substances 0.000 claims description 19
- 238000004519 manufacturing process Methods 0.000 claims description 13
- 238000000034 method Methods 0.000 claims description 11
- 238000000465 moulding Methods 0.000 claims description 2
- 239000002861 polymer material Substances 0.000 claims 4
- 239000007789 gas Substances 0.000 description 25
- 238000007789 sealing Methods 0.000 description 15
- 239000000463 material Substances 0.000 description 14
- 239000004033 plastic Substances 0.000 description 14
- 229920003023 plastic Polymers 0.000 description 14
- 238000010276 construction Methods 0.000 description 10
- 239000004621 biodegradable polymer Substances 0.000 description 7
- 229920002988 biodegradable polymer Polymers 0.000 description 7
- 238000010304 firing Methods 0.000 description 7
- 239000000843 powder Substances 0.000 description 7
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 description 4
- 238000012546 transfer Methods 0.000 description 4
- 230000009286 beneficial effect Effects 0.000 description 3
- 238000003780 insertion Methods 0.000 description 3
- 230000037431 insertion Effects 0.000 description 3
- 229910001369 Brass Inorganic materials 0.000 description 2
- 239000010951 brass Substances 0.000 description 2
- 239000002360 explosive Substances 0.000 description 2
- 229910052759 nickel Inorganic materials 0.000 description 2
- 230000000717 retained effect Effects 0.000 description 2
- 238000012360 testing method Methods 0.000 description 2
- 229910000978 Pb alloy Inorganic materials 0.000 description 1
- 239000004698 Polyethylene Substances 0.000 description 1
- 230000004888 barrier function Effects 0.000 description 1
- 238000002485 combustion reaction Methods 0.000 description 1
- 238000013461 design Methods 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 150000002739 metals Chemical class 0.000 description 1
- 239000002991 molded plastic Substances 0.000 description 1
- -1 polyethylene Polymers 0.000 description 1
- 229920000573 polyethylene Polymers 0.000 description 1
- 239000003380 propellant Substances 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
Images
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F42—AMMUNITION; BLASTING
- F42B—EXPLOSIVE CHARGES, e.g. FOR BLASTING, FIREWORKS, AMMUNITION
- F42B7/00—Shotgun ammunition
- F42B7/02—Cartridges, i.e. cases with propellant charge and missile
- F42B7/08—Wads, i.e. projectile or shot carrying devices, therefor
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- Engineering & Computer Science (AREA)
- General Engineering & Computer Science (AREA)
- Portable Nailing Machines And Staplers (AREA)
- Filling Or Discharging Of Gas Storage Vessels (AREA)
Description
- The present invention relates to projectile cartridges, such as shotgun cartridges, and in particular obturators and wads used in the construction of the cartridges, as for instance described in
SU1586360 A - As is known, shotgun cartridges typically comprise a projectile (e.g. a collection of lead or lead alloy shot), propellant powder (e.g. gunpowder) and a wad, all of which are housed within a tubular cartridge casing.
- The role of the wad (also referred to as wadding) is to transfer the thrust generated by the gunpowder when it combusts to the shot so as to force the shot to exit the gun at speed. In order to ensure an efficient transfer of force, the wad is configured to form a seal, initially, with the cartridge case and, once the gun has been fired, the barrel of the gun.
- When the seal formed by the wad is poor there can be gas leakage past the wad. This can lead to inconsistent ballistic results from one cartridge to the next, and other issues; such as increased recoil, lower performance and down-ranged striking energy.
- There are two main types of wad employed in shotgun cartridges; the plastic wad and the fibre wad.
- Plastic wads typically comprise a single moulded construction with three main parts, in the form of an obturator that is linked to a shot cup by way of a cushioning structure. With that said, in some moulded plastic wad constructions the cushioning structure may be omitted, particularly in situations where a larger shot cup is employed. It is the obturator that performs the sealing function when the gunpowder in the cartridge is ignited by the primer.
- The moulded construction of plastic wads enables them to deliver a more consistent seal than fibre wads. Typically plastic wads have a standard deviation average of about 25 bar pressure between shots.
- Fibre wads, on the other hand, typically have a two-part construction that comprises a powder card and a fibre driving wad. The powder card, which is typically just stamped out in a circular disc shape, acts as a barrier between the gunpowder and the fibre driving wad. The fibre wad provides a cushioning function to protect the shot from being deformed by the forces generated by the exploding gunpowder.
- Unfortunately, the quality of the seal formed by the fibre wad, and in particular the powder card, is not as good as that achieved by a plastic wad. As a consequence, cartridges with fibre wads offer less consistent results than shotgun cartridges with plastic wads. Typically fibre wads offer with a standard deviation average of about 40 bar pressure between shots.
- Despite their lower reliability, however, fibre wads are still commonly used. This is primarily due to the environmental issues relating to plastic wads, which do not degrade in the same way as fibre wads.
- International Patent Application
WO 94/10526 - With a view to delivering more consistent performing projectile cartridges, the present invention provides an improved projectile cartridge obturator in accordance with
claim 1. - The projectile cartridge obturator, which is moulded from a biodegradable polymer material, comprises: a main body having a first face, with a first centrally located projection spaced apart from a first annular skirt portion located on the periphery of the main body, and a second face, with a second centrally located projection spaced apart from a second annular skirt portion located on the periphery of the main body; wherein the free end of each annular skirt portion is configured to form a seal with the interior wall of a projectile cartridge case when the obturator is inserted into the case; and wherein the first annular skirt portion is further provided with a secondary seal spaced away from the free end of the first skirt portion, said secondary seal also configured to form a seal with the interior wall of the cartridge case.
- The provision of multiple sealing means on the obturator of the present invention delivers a reduction in gas leakage when the cartridge is fired, which helps to provide more consistent ballistic results from one cartridge to the next.
- Providing a seal on the free end of each skirt allows the explosive gases generated by the gunpowder when it ignites to get behind the skirt and urge the seal outwards to improve the seal formed, initially, against the surrounding walls of the cartridge casing and, subsequently, the gun barrel. By providing at least one skirt with an additional secondary seal at a different location on the skirt, the explosive gases can be harnessed to urge both the skirt's main seal and the secondary seal outwards.
- Preferably the second annular skirt portion may also be provided with a secondary seal spaced away from the free end of second annular skirt portion, wherein said secondary seal is also configured to form a seal with the interior wall of the case.
- It is has been found that the obturator of the present invention helps to greatly reduce the gas leakage in shotgun cartridges in a consistent manner. Tests have shown that cartridges employing the obturator of the present invention have demonstrated an improved standard deviation average in the region of 500 KPa pressure between shots.
- Preferably the obturator further comprises a vent in one or more of the seals formed by the first and second annular skirt portions and the secondary seals. The vent may take the form of a groove or channel (located in the obturator) that traverses each seal.
- The provision of a vent in one or more of the main or secondary seals is considered beneficial to the cartridge manufacture process, and in particular the manufacturing step of inserting the obturator into a cartridge case.
- Due to the increased sealing achieved by the provision of multiple seals around the perimeter of the obturator, air can become trapped within the case when the obturator is inserted. This can lead to technical difficulties during the cartridge manufacture process which can introduce imperfections into the obturator or the cartridge case that impair the quality of the obturator's gas sealing properties.
- It is envisioned that providing one or more vents in the seals of the obturator is sufficient to allow air to escape from the cartridge at the speeds associated with the insertion step but not at the greater speeds associated with the firing of the cartridge.
- As a result, the provision of vents in the seals facilitates the cartridge manufacture process without reducing the gas sealing properties of the final cartridge product during use.
- Preferably each of the seals of the obturator is provided with a vent to facilitate the escape of air during the obturator insertion step.
- In situations where more than one of the seals is provided with a vent, it is considered particularly preferable that the vents on adjacent seals are offset from one another around the periphery of the obturator. By offsetting the vents in this way it is possible to create a more torturous path around the obturator.
- Again, the torturous or ponderous path taken by gases trying to pass the obturator has less of an impact at the speeds associated with the insertion of the obturator into the cartridge case than it does at the faster speeds associated with the firing of the cartridge.
- In this way the obturator provides improved sealing when needed (i.e. during the combustion of the gun powder) without impeding the manufacture of the cartridge.
- Preferably the first and/or second centrally located projection may comprise cut out regions that define one or more structural ribs. In this way the amount of material required to form the obturator can be reduced without impairing the structural strength of the obturator. It is envisioned that alternative centrally located projections may be provided with alternative structure arrangements by making different cut out regions. For example, in one preferred alternative the cut outs may define one or more co-axially located circular projections.
- Either way, reducing the amount of material used to form the obturator makes it more economically viable to construct the obturator of the present invention from a biodegradable polymer material, which might otherwise be commercially unattractive due to manufacturing costs.
- It is envisioned that it is particularly preferable to form the obturator from a biodegradable polymer material when it is used in place of the powder card in a fibre wad. With that said, the obturator of the present invention can be used in both plastic wads and fibre wads.
- In view of this, in a further aspect of the present invention there is provided a projectile cartridge wad that comprises a projectile cartridge obturator of the present invention. In this aspect the cartridge wad may comprise either a fibre wad or a plastic wad.
- In the case of a fibre wad for a projectile cartridge the wad further comprises a fibre plug.
- In the case of plastic wad for a projectile cartridge the wad further comprises a shot cup.
- Preferably the plastic wad may further comprise a cushioning structure that is located between the obturator and the shot cup. Further preferably the cushioning structure is connected to the second centrally located projection of the obturator.
- Further preferably the obturator, cushioning structure, when present, and the shot cup are formed as a single moulded piece.
- For situations where a cushioning structure is not required the present invention provides a projectile cartridge obturator comprising: a main body having a first face, with a first centrally located projection spaced apart from a first annular skirt portion located on the periphery of the main body, and a second face, upon which a shot cup is provided, with a second annular skirt portion located on the periphery of the main body; wherein the free end of each annular skirt portion is configured to form a seal with the interior wall of a projectile cartridge case when the obturator is inserted into the case; and wherein the first annular skirt portion is further provided with a secondary seal spaced away from the free end of the first skirt portion, said secondary seal also configured to form a seal with the interior wall of the cartridge case. In the above arrangement it will be appreciated that the second face of the obturator defines the base of the shot cup, thereby allowing the length of the shot cup to be maximised within the size restrictions of the complete projectile cartridge.
- In a yet further aspect the present invention provides a projectile cartridge comprising the obturator or wad of the present invention.
- The present invention also provided a method of manufacturing a projectile cartridge, said method comprising: moulding an obturator from a biodegradable polymer material, said obturator comprising a main body having a first face, with a first centrally located projection spaced apart from a first annular skirt portion located on the periphery of the main body, and a second face, with a second centrally located projection spaced apart from a second annular skirt portion located on the periphery of the main body, and wherein at least the first annular skirt portion is provided with a secondary seal spaced away from the free end of the first annular skirt; inserting the obturator into a projectile cartridge case between a charge of gunpowder and one or more cartridge projectiles (e.g. shot) such that the free ends of the annular skirts and said at least one secondary seal form seals with the interior wall of the cartridge case; and closing the case to encapsulate its contents.
- Preferably the second annular skirt portion may also be provided with a secondary seal spaced away from the free end of second skirt portion, wherein said secondary seal is also configured to form a seal with the interior wall of the case.
- Preferably the method may further comprise providing each of the annular skirts and said at least one secondary seal with a vent. As noted above, the provision of one or more vents in the obturator's seals makes the step of inserting the obturator into the cartridge case, with which it forms a sealing relationship, easier.
- Further preferably, the vents provided in adjacent seals may be offset from one another around the periphery of the obturator. As noted above, arranging the vents in this way helps to define a torturous gas flow path around the obturator, which reduces gas leakage.
- Additionally or alternatively, it is considered preferable that the first centrally located projection, and further preferably the second centrally located projection too, may be moulded with cut outs that define one or more structural ribs. It is envisioned that alternative structural arrangements may be provided by adopting different cut outs.
- As noted above, reducing the amount of material required to manufacture the obturator can significantly reduce cartridge manufacturing costs, this is considered particularly beneficial because the obturator is moulded from a biodegradable polymer material.
- Preferably a fibre plug may be provided between the obturator and the cartridge projectile. Alternatively, the obturator may be moulded as part of a combined wad component that also comprises a shot cup, in which said one or more cartridge projectiles are received. Preferably, the combined wad component may also comprise a cushioning structure arranged between the obturator and the shot cup.
- As noted above, it is considered advantageous for the obturator and also the combined wad component of the present invention to be moulded from a biodegradable polymer material.
- The various aspects of the present invention will now be described with reference to the preferred embodiments shown in the drawings, wherein:
-
Figure 1 shows a side view of an obturator according to a preferred embodiment of the present invention; -
Figure 2 shows a transparent view of selected region 'A' of the obturator ofFigure 1 ; -
Figure 3 show a top plan view of the obturator ofFigure 1 ; -
Figure 4 shows a shotgun cartridge employing an obturator of the present invention; -
Figure 5 shows a side view of an alternative embodiment of obturator of the present invention; -
Figure 6 shows a perspective view of the obturator shown inFigure 5 ; -
Figure 7 shows a sectional perspective view of the obturator shown inFigure 5 ; and -
Figure 8 shows a projectile cartridge wad comprising a further preferred embodiment of the obturator of the present invention; -
Figure 9 shows an alternative projectile cartridge wad in which the cushioning structure is not used; and -
Figure 10 shows a shotgun cartridge employing an alternative obturator according to the present invention. - The present invention provides for improved obturators for use in projectile cartridges for firearms, such as shotguns. In a projectile cartridge, such as a shotgun cartridge, the main role of the obturator is to provide a gas seal that prevents the dissipation of the gases that are generated during the ignition of the gunpowder within the cartridge. By providing an effective gas seal, the obturator helps to ensure an efficient transfer of the forces generated by the gunpowder to the projectile (e.g. shot) held in the cartridge.
- The obturator of the present invention is designed to provide a more reliable gas seal that in turn provides more consistent results when the cartridges are fired.
- A preferred embodiment of the
obturator 1 of the present invention is shown inFigure 1 . Theobturator 1, which is moulded from a biodegradable polymer material, is formed with amain body 2. - When viewed in plan, the
main body 2 has a circular shape that corresponds to the circular shape of the inner walls of a cartridge case or casing (seeFigure 4 ). - Around the periphery of the
main body 2 are provided a firstannular skirt portion 3 and a secondannular skirt portion 4. The first and second annular skirt portions extend away from one another in opposite directions to a free end. - In the preferred embodiment shown in
Figure 1 , both skirts increase in diameter as they extend away from the main body of the obturator towards their respective free ends. In this way the free end of each annular skirt portion is configured to form a seal with the inner wall of a cartridge casing when the cartridge is constructed. - It is envisioned that alternative seal configurations may be employed on the free ends of the annular skirt portions.
- For example, in one alternative arrangement each annular skirt may retain a constant diameter as it extends away from the main body of the obturator and instead be provided with a ring that projects outwards from each skirt at the free end thereof. It is this ring that forms a seal with the inner wall of a cartridge casing when the cartridge is constructed.
- Also, although the first and second annular skirt portions are shown in
Figures 1 and 2 as being of equal length, it is envisaged that the respective lengths of theannular skirt portions - In the preferred embodiment shown in
Figures 1 and 2 , each of theannular skirt portions ring - As will be appreciated from
Figures 1 and 2 , the secondary seal rings 5, 6 are shaped so that the extent to which they extend radially out from the skirt increases the closer they get to the free end of their respective annular skirt portion. - It is envisaged that in embodiments of the present invention where an outwardly projecting sealing ring is provided at the free end of each respective skirt, said rings may have a similar shape to the secondary seal rings 5, 6 that are shown in
Figures 1 and 2 . - The construction of the
annular skirt portions Figure 2 , which shows a partially exposed close up of region 'A' ofFigure 1 . - Also, for increased clarity the
annular skirt portions Figure 2 as transparent so that the interior of the obturator can be appreciated. - As can be seen from
Figure 2 , in addition to an annular skirt portion, each face of themain body 2 is provided with a centrally locatedprojection - That is to say, the first centrally
location projection 7 extends from the first face of themain body 2 and is spaced apart from firstannular skirt portion 3 and the second centrallylocation projection 8 extends from the second face of themain body 2 is spaced apart from secondannular skirt portion 4. - Spacing each centrally located projection away from their respective annular skirt portion serves to create an
annular channel 9 adjacent to each face of the main body. During the firing of a cartridge theannular channel 9 allows pressurised gases to get into the space behind the annular skirt portions and, in so doing, urge the skirts (and their associated seals) outwards towards the inner walls of the cartridge casing and subsequently the gun barrel. In this way an improved gas seal is created between obturator and the walls of the casing/gun barrel. - Turning now to
Figure 3 , which shows the obturator ofFigure 1 in plan, the concentric arrangement of theannular skirt portion 3,annular channel 9 and centrally locatedprojection 7 can be better appreciated. - In the preferred embodiment shown, the centrally located
projection 7 is provided with cut out regions that serve to definestructural ribs 10, which are shown in an 'X' configuration. It is appreciated that alternative cut out arrangements can be adopted without departing from the scope of the present invention. For example, the centrally located projection may be provided with cut outs that achieve castellation or alternatively define one or more co-axially located circular projections. - Although not essential to the operation of the obturator of the present invention, it is considered beneficial to adopt cut out regions in order to reduce the total amount of material used to construct the obturator whilst still maintaining its structural integrity.
- Reducing the amount of material required to construct the obturator is particularly advantageous when making it out of biodegradable materials, because otherwise the cost of manufacturing the cartridge might be commercially unattractive.
- It is envisioned that the
obturator 1 of the present invention can be used in place of a standard powder card in a fibre wad based cartridge. In this regard,Figure 4 shows afibre wad cartridge 20 employing theobturator 1 of the present invention. - The
cartridge 20 comprises acartridge casing 21, which is commonly made from plastic and houses the various components of the cartridge. At the base of thecartridge 20 is provided theprimer 25, which is usually formed as a brass or nickel head attached to one end of thecasing 21. - Adjacent to the
primer 25 is thegunpowder charge 24, which is retained within the casing between the primer and theobturator 1. Before the cartridge is fired, theobturator 1 keeps thegunpowder 24 separate from thefibre plug 23. - It is the role of the
fibre plug 23 to act as a packer that allows the height of the shot to be adjusted within the cartridge. The fibre plug also provides a cushioning function, which helps to prevent theshot 22 from being deformed by the considerable forces generated by the exploding gunpowder. This is particularly important when the shot (i.e. the cartridge projectile) if formed from softer metals because the shot deformation can greatly affect the firing pattern achieved by a cartridge. - Turning now to
Figures 5, 6 and7 , an alternative preferred embodiment of the obturator of the present invention will now be described. Theobturator 30 shown inFigure 5 is similar in construction to that shown inFigure 1 , with amain body 32 that comprises oppositely extendingannular skirt portions - As before, the annular skirt portions are provided with secondary sealing means in the form of
annular rings - Preferably each ring has a generally triangular cross-section. However it is envisioned that alternative configurations (e.g. 'D' shaped cross-section) may be adopted provided they still are still capable of achieving a sealing relationship with the inner walls of the cartridge casing/gun barrel.
- Although not visible from
Figure 5 , it will be appreciated fromFigures 6 and7 that this alternative embodiment of the obturator of the present invention is also provided with the centrally locatedprojections annular channel 38 provided in the obturator shown inFigures 1 to 3 . - The main difference between the obturator shown in
Figures 1 to 3 and the alternative embodiment shown inFigures 5 to 7 is the provision ofvents 31a-31d in the various seals located about the periphery of theobturator 30. - As will be appreciated upon consideration of
Figures 5 to 7 as a whole, the firstannular skirt portion 33 is provided withvent 31a and the secondary seal on the firstannular skirt portion 35 is provided withvent 31b. Further, the secondannular skirt portion 34 is provided withvent 31d and the secondary seal on the secondannular skirt portion 36 is provided withvent 31c. - Each of the
vents 31a-31d takes the form of a small cut out channel or groove in the sealing surface of the respective seals. The vents are configured to traverse each seal and allow a limited flow of gases through each of the seals. This limited flow of gas past the obturator's seals is sufficient to prevent the build-up of pressure within a cartridge during manufacture because the speed with which a obturator is inserted into a cartridge casing is much less than the speed of the gases generated when the gunpowder explodes (i.e. during the firing of a gun). - In contrast, the gases generated when the gunpowder in the cartridge is ignited are prevented from leaking past the obturator, which helps to ensure a more efficient transfer of forces from the exploding gunpowder to the cartridge projectiles (e.g. shot) held at the crimped leading end of the cartridge casing.
- The effectiveness of the multiple seals' ability to prevent unwanted gas leakage during firing without impairing the cartridge manufacturing process is further enhanced by the off-set arrangement of the vents shown in
Figures 5 to 7 . - In this regard it will be observed that adjacent vents (e.g. 31a and 31b; 31b and 31c; etc...) are located 180 degrees away from one another around the outer perimeter of the
obturator 30. By providing the vents off-set in this way theobturator 30 is capable of forming a torturous flow path for any gases that try to by-pass the obturator's gas seals. - Although the obturator shown in
Figures 5 to 7 has a single vent in each of the obturator's seals, it is envisioned that multiple seals may be provided in each seal. In such an arrangement the vents may or may not be off-set from one another around the periphery of the obturator. -
Figures 6 and7 show three dimensional views of the second preferred embodiment of theobturator 30 of the present invention, in which the centrally locatedprojections annular channels 38 can be better appreciated. - These figures also clearly show the cut out regions in the centrally located
projection 37 that serve to define thestructural ribs 39. Although not shown, it should be appreciated that centrally locatedprojection 40 may preferably also provided with a similar arrangement of cut outs regions and structural ribs. Once again it is envisaged that the centrally located projections may have alternative configurations (e.g. castellation or co-axially located circular projections). - Both of the above described embodiments of the obturator of the present invention are shown as having a secondary seal on each annular skirt portion. However it is envisaged that in some embodiments of the present invention a secondary seal may be provided on only one of the annular skirt portions without departing from the present invention.
- Conversely, it is also envisioned that if the annular skirt portion is of a suitable length, it may be possible to accommodate more than one secondary seal on that annular skirt portion to further improve the gas sealing function of the skirt.
- In a further aspect of the present invention, the obturator of the present invention may be incorporated into a combined
wad structure 50. A first preferred embodiment of this combinedwad structure 50 is shown inFigure 8 . - The
structure 50, which is preferably moulded as a single unitary construction from a suitable plastics material such as polyethylene, comprises anobturator 51, acushioning structure 57 and ashot cup 58. - As with the obturators shown in
Figures 1 to 7 , theobturator 51 of the combinedwad structure 50 is provided with a firstannular skirt portion 52 and a secondannular skirt portion 53. Once again eachannular skirt portion - Also, as with the obturators shown in
Figures 1 to 7 , theobturator 51 of the combinedwad structure 50 is provided with a first centrally located projection that is preferably formed with cut out regions/structural ribs. - However, in order to achieve the unitary construction, the construction of the second centrally located projection is adapted to accommodate the
cushioning structure 57, which projects from the opposite face of the obturator to the first centrally located projection. - It will be appreciated that, as with the fibre plug shown in
Figure 4 , the role of thecushioning structure 57 is to minimise the deformation of the shot held within the cartridge when the gunpowder is ignited. - The skilled person will appreciate that the configuration of the cushioning structure can be varied without departing from the general concept of the present invention, that is to say the provision of the improved obturator design.
- The
cushioning structure 57 serves to connect theobturator 51 to theshot cup 58, within which one or more cartridge projectiles (e.g. shot) are housed in the final cartridge product. Again, the skilled person will be well versed in the structural considerations associated with the shot cup and therefore these will not be covered in any detail here. - It is envisioned that in some variants of the combined wad structure of the present invention, the cushioning structure may be omitted (for example to accommodate a large shot cup). An example this arrangement of combined
wad structure 60 is shown inFigure 9 . - As with the combined wad structure shown in
Figure 8 , theobturator 61 is provided with a firstannular skirt portion 62 and a secondannular skirt portion 63. In addition, eachannular skirt portion obturator 61. - Although not visible in
Figure 9 , it should be appreciated that theobturator 61 is provided with a first centrally located projection that is preferably formed with cut out regions/structural ribs. However, as theshot cup 68 is connected directly to theobturator 61, there are no cut outs in the upper face of the obturator. Instead, the upper face of the obturator effectively forms the base of the shot cup. - It is appreciated that in the arrangement shown in
Figure 9 only the seals formed by the first skirt benefit from being urged outwards (i.e. towards the cartridge casing and the gun barrel) by gases that can get into the cut out regions of theobturator 61. With that said, testing has shown that the seal formed by the second skirt are also urged outwards as they are set back by the extreme forced generated when the gun power of the cartridge is ignited. As a result, effective seals are once again formed and a constant firing outcome is achieved. -
Figure 10 shows ashotgun cartridge 70 employing a variant of the combinedwad structure 50a shown inFigure 8 . The cartridge has most of the same components as theshotgun cartridge 20 shown inFigure 4 . As such the same reference numbers are used for those components that are common to both cartridge types. - In this regard, the combined
wad structure 50a is housed within thecartridge casing 21, which is commonly made from plastic and houses the various components of the cartridge. At the base of thecartridge 70 is provided theprimer 25, which is usually formed as a brass or nickel head attached to one end of thecasing 21. - Adjacent to the
primer 25 is thegunpowder charge 24, which is retained within the casing between the primer and theobturator 51a of the combinedwad structure 50a. Theshot 22 is held within theshot cup 58a of the combinedwad structure 50a.
Claims (15)
- A projectile cartridge obturator (1, 30, 51, 51a, 61) moulded from a polymer material, said obturator comprising:a main body (2, 32) having a first face with a first centrally located projection (7, 37) spaced apart from a first annular skirt portion (3, 33, 52, 62) located on the periphery of the body and a second face with a second centrally located projection (8, 40) spaced apart from a second annular skirt portion (4, 34, 53, 63) located on the periphery of the body;wherein the free end of each annular skirt portion (3, 4, 33, 34, 52, 53, 62, 63) is configured to form a seal with the interior wall of a projectile cartridge case (21) when the obturator (1, 30, 51, 51a, 61) is inserted into the case (21); andwherein the first annular skirt portion is further provided with a secondary seal (5 6, 35, 36, 54, 55, 64, 65) spaced away from the free end of the first skirt portion, said secondary seal also configured to form a seal with the interior wall of the cartridge case (21),characterized in that the polymer material from which the obturator is moulded is biodegradable.
- The obturator of claim 1, wherein the second annular skirt portion is also provided with a secondary seal (5, 6, 35, 36, 54, 55, 64, 65) spaced away from the free end of second skirt portion, said secondary seal also configured to form a seal with the interior wall of the case.
- The obturator of claim 1 or 2, further comprising a vent (31a, 31b, 31c, 31d, 56a, 56b, 56c, 56d, 66a, 66b, 66c, 66d) in one or more of the seals formed by the first and second annular skirt portions (3, 4, 33, 34, 52, 53, 62, 63) and the secondary seals (5, 6, 35, 36, 54, 55, 64, 65).
- The obturator of claim 3 wherein the vents provided in adjacent seals are offset from one another around the periphery of the obturator.
- The obturator of any of the preceding claims, wherein the first centrally located projection (7, 37) and/or the second centrally located projection (8, 40) comprises cut out regions that define one or more structural ribs (10, 39).
- A projectile cartridge wad (50, 50a, 60) comprising a projectile cartridge obturator (51, 51a, 61) of any of the preceding claims.
- The wad of claim 6, further comprising either:a fibre plug (23); ora cushioning structure (57) and a shot cup (58, 58a).
- The wad of claim 7, wherein the cushioning structure (57) is connected to the second centrally located projection of the obturator (51, 51a); and wherein
preferably the obturator (51, 51a), cushioning structure (57) and the shot cup (58, 58a) are formed as a single piece. - A projectile cartridge (70) comprising an obturator (1, 30, 51, 51a, 61) in accordance with claims 1 to 5 or a wad (50, 50a, 60) in accordance with claims 6 to 8 received within a case (21).
- A method of manufacturing a projectile cartridge (70), said method comprising:moulding an obturator (1, 30, 51, 51a, 61) from a polymer material, said obturator comprising a main body (2, 32) having a first face, with a first centrally located projection (7, 37) spaced apart from a first annular skirt portion (3, 33, 52, 62) located on the periphery of the body, and a second face, with a second centrally located projection (8, 40) spaced apart from a second annular skirt portion (4, 34, 53, 63) located on the periphery of the body, wherein the free end of each annular skirt portion (3, 4, 33, 34, 52, 53, 62, 63) is configured to form a seal with the interior wall of a projectile cartridge case (21) when the obturator (1, 30, 51, 51a, 61) is inserted into the case (21);inserting the obturator (1, 30, 51, 51a, 61) into a projectile cartridge case (21) between a charge of gunpowder (24) and one or more cartridge projectiles (22) such that the annular skirts (3, 4, 33, 34, 52, 53, 62, 63) form seals with the interior wall of the cartridge case (21); andclosing the case (21) to encapsulate its contents; andwherein the first annular skirt portion being further provided with a secondary seal (5, 6, 35, 36, 54, 55, 64, 65) spaced away from the free end of said first skirt portion, said secondary seal also configured to form a seal with the interior wall of the cartridge case (21),characterized in that the polymer material from which the obturator is moulded is biodegradable.
- The method of claim 10, wherein the second annular skirt portion is also provided with a secondary seal (5, 6, 35, 36, 54, 55, 64, 65) spaced away from the free end of second skirt portion, said secondary seal also configured to form a seal with the interior wall of the case.
- The method of claim 11 or 12, further comprising providing each of the annular skirts and said at least one secondary seal with a vent (31a, 31b, 31c, 31d, 56a, 56b, 56c, 56d, 66a, 66b, 66c, 66d).
- The method of claim 12, wherein the vents provided in adjacent seals are offset from one another around the periphery of the obturator.
- The method of any one of claims 10 to 13, wherein the first centrally located projection, and preferably also the second centrally located projection, are moulded with cut outs that define one or more structural ribs.
- The method of any one of claims 10 to 14, further comprising either:providing a fibre plug (23) between the obturator and the cartridge projectile; orproviding the obturator as part of a moulded combined wad component (50, 50a, 60) that also comprises a cushioning structure (57) and a shot cup (58, 58a), in which the cartridge projectile (22) is received.
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
GB2000379.4A GB2585964B (en) | 2020-01-10 | 2020-01-10 | Improvement relating to projectile cartridge obturators and wads and cartridges employing such |
PCT/GB2020/053211 WO2021140311A1 (en) | 2020-01-10 | 2020-12-15 | Improvement relating to projectile cartridge obturators and wads and cartridges employing such |
Publications (2)
Publication Number | Publication Date |
---|---|
EP4088083A1 EP4088083A1 (en) | 2022-11-16 |
EP4088083B1 true EP4088083B1 (en) | 2024-07-17 |
Family
ID=69626403
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP20828105.5A Active EP4088083B1 (en) | 2020-01-10 | 2020-12-15 | Improvement relating to projectile cartridge obturators and wads and cartridges employing such |
Country Status (4)
Country | Link |
---|---|
US (1) | US20230349678A1 (en) |
EP (1) | EP4088083B1 (en) |
GB (1) | GB2585964B (en) |
WO (1) | WO2021140311A1 (en) |
Family Cites Families (20)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US579853A (en) * | 1897-03-30 | Shot-carrying shell | ||
US1659649A (en) * | 1923-07-30 | 1928-02-21 | Western Cartridge Co | Wad for shot shells |
FR1136976A (en) * | 1955-11-14 | 1957-05-22 | Bouchon L L Soc Du | Elastico-pneumatic filling for hunting cartridges |
CH349902A (en) * | 1959-04-21 | 1960-10-31 | R L Metal & Plastic Sa | Hunting cartridge wad |
US3022734A (en) * | 1959-07-27 | 1962-02-27 | Remington Arms Co Inc | Shot shell wad |
FR1286935A (en) * | 1961-02-17 | 1962-03-09 | Manufrance | Shutter seal for shotgun cartridges and other weapons |
US3127837A (en) * | 1961-04-27 | 1964-04-07 | Driaire Inc | Shot shell construction |
BE639052A (en) * | 1962-10-23 | |||
US3279375A (en) * | 1964-04-27 | 1966-10-18 | Herter Inc S | Shotgun shell wad |
US3368489A (en) * | 1966-04-26 | 1968-02-13 | Herter Inc S | Shotshell over-powder wad and shot cup |
FR2063728A5 (en) * | 1969-10-28 | 1971-07-09 | Piegay Marcel | Wad for sporting cartridges |
US3750580A (en) * | 1970-11-13 | 1973-08-07 | Asahi Chemical Ind | Wads for charging shot of shot gun |
FR2141459B1 (en) * | 1971-06-03 | 1973-06-29 | Philippe Maurice | |
FR2199861A5 (en) * | 1972-09-15 | 1974-04-12 | Rey Freres Ets | |
CH662878A5 (en) * | 1985-08-15 | 1987-10-30 | Gilbert Cornelius | Wad for shot cartridge |
US4864934A (en) * | 1988-12-12 | 1989-09-12 | Olin Corporation | Industrial shotshell having a load-stabilizing assembly |
SU1586360A1 (en) * | 1988-12-20 | 1996-05-10 | С.И. Баскин | Wad for cartridges |
US5150909A (en) * | 1991-04-04 | 1992-09-29 | Edwin Fitzwater | Air gun pellet design |
CZ108995A3 (en) * | 1992-10-28 | 1995-09-13 | Olin Corp | Waterproof plug of a cartridge case |
US7150229B2 (en) * | 2004-04-27 | 2006-12-19 | Olin Corporation | Projectile wad for ammunition cartridges |
-
2020
- 2020-01-10 GB GB2000379.4A patent/GB2585964B/en active Active
- 2020-12-15 EP EP20828105.5A patent/EP4088083B1/en active Active
- 2020-12-15 US US17/791,352 patent/US20230349678A1/en active Pending
- 2020-12-15 WO PCT/GB2020/053211 patent/WO2021140311A1/en unknown
Also Published As
Publication number | Publication date |
---|---|
GB2585964A (en) | 2021-01-27 |
US20230349678A1 (en) | 2023-11-02 |
GB202000379D0 (en) | 2020-02-26 |
WO2021140311A1 (en) | 2021-07-15 |
EP4088083A1 (en) | 2022-11-16 |
GB2585964B (en) | 2021-12-15 |
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