GB2427671A - Air gun gas storage system - Google Patents

Abstract

An air gun 1 having a gas storage system which stores pressurised gas for use in propelling an air gun projectile. The air gun 1 comprises a barrel 3 which extends within an outer housing 14 such that a gas chamber 13 is defined between the outer housing 14 and the barrel 3.

Description

AN AIR GUN WITH AN IMPROVED GAS STORAGE SYSTEM

The present invention relates to an air gun, and in particular to an air rifle, having a gas storage system which stores pressurised gas for use in propelling an air gun projectile.

Air guns, such as air rifles, use compressed gas to propel a projectile at great speed. A conventional air gun comprises a barrel into which a projectile may be inserted, a compression chamber into which air under pressure may be delivered, a trigger, and a valve mechanism comprising a movable valve member operable by the trigger.

There are three basic types of air gun, namely pump type guns, spring guns, and pre-charged gas guns, classified according to their respective firing mechanisms. In pump type air guns a reservoir of compressed gas is built up by manually pumping air using a lever mechanism which actuates a piston. In spring powered air guns, a spring is compressed behind a piston, such that when the spring is released a piston is actuated to rapidly compress and release the gas contained within. Finally, precharge air guns are provided with compressed gas which is stored in cylinders, similarly to air in a scuba tank. The present invention concerns the development of a gas storage system for a pre-charge air gun, such as an air rifle.

In pre-charge air rifles, compressed air must be provided by a compressor, or from a compressed gas source such as a scuba tank. The compressed gas is stored in a gas reservoir, such as a gas cannister, which is attached to the air rifle. In air rifles, a gas cannister is commonly attached to the front of the action of the rifle underneath and parallel to the barrel, or is placed at the rear of the action of rifle as part of the stock or butt. In recent years there has been a trend for larger and larger gas canisters in order to increase the number of shots that can be made between re-filling the canister.

However, the provision of an external gas canister can make an air rifle unwieldy and difficult to handle. In particular the provision of an external gas canister in locations as are described above is physically obtrusive, and when placed under the barrel at the front of the action and rifle, prevents the stock, which is used by the user to hold and steady the rifle from extending as far as would be possible on a traditional firearm.

In addition, such gas canisters, in particular the larger canisters, detract considerably from the visual appearance of such rifles. Many air rifle owners desire air rifles that visually resemble the fire arm equivalents. As fire arms do not require, and are not provided with such gas canisters, it is undesirable for them to be visually apparent on an air rifle.

It is therefore desirable to provide an improved gas storage system for an air rifle which addresses the above problems, and/or which provides improvements generally.

According to the present invention, there is provided an air gun, as described in the accompanying claims.

In a particular embodiment, and aspect of the invention, there is provided an air gun comprising a barrel and a gas storage system. The gas storage system comprises a gas chamber, which is defined between an outer housing and the outer diameter of the barrel. The barrel extends within the outer housing such that the outer housing surrounds at least part of the length of the barrel. In this way the gas storage system is integrated into the barrel section of the air gun. Externally, the outer housing appears to be the barrel of the gun. This arrangement advantageously obviates the requirement for a separate gas canister which is physically and visually obtrusive.

Preferably, the barrel and the outer housing are co-axial.

Alternatively, the axis of the barrel may be offset from, but parallel to, the axis of the outer housing. it is also preferable that the outer housing is a cylinder.

The gas chamber may be sealed at a first end by a front sealing member and at a second end by a rear sealing member. A gas pathway may be defined between the rear sealing member and the outer diameter of the barrel. The gas pathway connects the gas chamber to a valve chamber of the air gun. This enables the gas chamber to be filled with pressurised gas, and for pressurised gas to exit the gas chamber to propel a projectile from the air gun.

Preferably, the air gun of the claimed invention is an air rifle.

The invention will now be described by way of example only with reference to the accompanying drawings in which:- Figure 1 is an illustration of an air rifle according to an embodiment of the invention; Figure 2 is an illustration similar to Figure 1, but of a prior art air rifle having a gas cylinder at the front of the rifle; Figure 3 is a sectional view of the barrel section and action of the air rifle of Figure 1; Figure 4 is a more detailed sectional view of the barrel and the action shown in Figure 3; Figure 5 is a yet more detailed sectional view of the barrel and action shown in Figure 4.

Referring to Figure 1, the air rifle 1 comprises a barrel section 2, an action 4, a stock 5 and a butt 6. In use the rifle 1 is held by the user and supported by the stock 5 and the butt 6.

The barrel section 2 comprises a barrel 3 which extends within, and is surrounded by an outer housing 14. The outer housing 14 is cylindrical, and extends along most of the length of the barrel 3. Alternatively, the outer housing 14 may extend along at least part of the length of the barrel 3. The barrel section 2 comprises a first end 17 adjacent the exit orifice 19 of the barrel 3, and a second end 18 abutting the action 4. The barrel 3 has an outer diameter 11 and an inner diameter 10. Outer housing 14 has an inner diameter 24 and an outer diameter 22. The barrel 3 and the outer housing 14 are co- axial, i.e. they share a common longitudinal central axis. However, in an alteratjve embodiment the axis of the barrel 3 may be offset from, but still parallel to, the axis of the outer housing 14. In a yet further variation the axes of the outer housing 14 and the barrel 3 may be angled relative to each other.

An annular gap is defined between a outside surface and outer diameter 11 of the barrel 3 and a inside surface and inner diameter 24 of the outer housing 14. An annular gas chamber 13 is thereby defined between the barrel, and the outer housing 14. The gas chamber 13 surrounds at least part of the circumference of the barrel 3, and preferably surrounds the entire circumference of the barrel 3.

The gas chamber 13 is sealed at the first end 17 of the barrel section 2 by an front sealing member 16, and at the second end 18 of the barrel section 2 by inlet adapter 15.

The barrel 3 extends through front sealing member 16, such that front sealing member 16 provides a seal between the inner diameter 24 of the outer housing 14 and the outer diameter 11 of the barrel 3. Preferably the barrel 3 extends beyond the front sealing member 16. Alternatively, the barrel 3 may terminate at the front sealing member 16.

Front sealing member 16 comprises an annular disc and seal arrangement. Resilient sealing members extend around the inner diameter 40 and outer diameter 42 of the front sealing member 16, such that a gas-tight seal is formed between the inner diameter 40 of the front sealing member 16 and the outer diameter 11 of the barrel 3, and between the outer diameter 42 of the front sealing member 16 and the inner diameter 24 of the outer housing 14.

Alternatively, the front sealing member 16 may be of any suitable means for sealing the end of the gas chamber 13 and between the outer diameter 11 of the barrel 3 and the inner diameter 24 of the outer housing 14.

An inlet adapter 15 seals gas within the gas reservoir 13, and provides a locating and securing means for the outer housing 14 as well as connection to the remainder of the air gun 1 and action 4. The inlet adapter 15 comprises a front section 36 and a rear section 38. The outer diameter of the front section 36 contacts the inner diameter 24 of the outer housing 14. A groove extends around the periphery of the front edge of the front section 36, into which a resilient sealing member 32 is inserted. The resilient sealing member 32 prevents gas from escaping from within the gas chamber 13 between the outer diameter of the insert and the inner diameter 24 of the outer housing 14.

Inlet adaptor 15 surrounds the barrel 3 along part of the length of the barrel 3 at the rear of the barrel 3.

Resilient sealing members 27 and 28 are contained in grooves extending around the outer periphery of the rear section 38 of inlet adapter 15 either side of the aperture 21 relative to the length of the inlet adapter 15. These sealing members prevent gas from passing between the inner diameter 39 of the action 4 and the outer diameter of the rear section 38 of inlet adapter 15. A further resilient member 29 is provided in a groove which extends around the inner periphery of the rear face of the rear section 38 of inlet adapter 15, thereby sealing the gas pathway 26 and preventing gas from passing any further therealong.

The inlet adapter 15 is attached to the action 4 by a screw thread section 30. The outer housing 14 is attached to the inlet adapter 15 by a plurality of radially located screws.

Alternatively, the outer housing 14 may be attached to the inlet adapter 15 by a screw thread, or attached by any other suitable means.

As can be seen from the exploded section view 25 of Figure 5, the inner diameter 34 of inlet adapter 15, and outer diameter 11 of the barrel 3 are radially spaced apart such that there is a small clearance therebetween defining a gas pathway 26. Gas is thereby able to travel, in use, via the gas pathway 26 and a connecting aperture 21 between a valve chamber 20 and the gas chamber 13. In this manner, in use, pressurised gas can be supplied from the gas chamber 13 to the valve chamber 20 and from the valve chamber 20 to the gas chamber 13 with the gas chamber 13 and valve chamber 20 in fluid communication with each other.

The valve chamber 20, and remainder of the firing mechanism (not shown), of the air gun 1 are of a conventional configuration, and so will not be described in detail. The firing mechanism is actuated by a trigger 7. When the trigger 7 is pulled, the firing mechanism channels pressurised gas supplied to the valve chamber 20 from the gas chamber 13 to the end 8 of the barrel 3 of the air gun 1, where a projectile is loaded in position. The pressurised gas contacts the projectile at this point and forces the projectile down an inner bore 12 of the barrel 3 and subsequently out of the end of the barrel 3.

As in conventional pre-charged rifles, a supply of pressurised compressed gas, for example from a gas cylinder or compressor, can be connected to the air gun 1 and supplied to the valve chamber 20 via suitable connections and valve arrangements (not shown) in order to charge the gas chamber 13 with pressurised gas. The pressurjsed gas contained within the gas chamber 13 is typically provided at a pressure of 200 bar.

By way of comparison, Figure 2 shows a prior art

conventional air rifle having a gas canister 9 which is attached to the stock 5 of the rifle 1 underneath the barrel 3. This can be contrasted with the air rifle of the present invention. The front section of the stock 5 terminates at the attachment point of the gas canister 9, and as such does not extend to contact the underside of the barrel 3. The gas canister 9 renders the rifle unwieldy and in use can be physically obtrusive. In addition, the visual impact of the gas canister 9 is significant, as can been see in from Figure 2.

In contrast, the air rifle 1 of Figure 1 and an embodiment of the claimed invention, provides a gas reservoir which is integrated into the barrel section 2, thereby obviating the need for an external gas canister such as gas canister 9.

The absence of a gas canister 9 enables the front end of the stock 5 to be continued such that it extends significantly further along the length of the barrel than in the air gun of Figure 2. As such it is possible to provide a stock which contacts the barrel section 2 along its underside, thereby providing a rifle which is easier to handle.

As can also be appreciated by contrasting the air rifle of the claimed invention shown in Figure 1, and the prior art air rifle of Figure 2, the air rifle of Figure 1 in accordance with an embodiment of the invention is less bulky, both in appearance and use, since it eliminates the use of a separate gas canister 9, which in the prior art air rifle shown in Figure 2 detracts from the overall visual effect of the rifle, as well as making the rifle more cumbersome to handle. As a result, the air rifle of Figure 1 is easier to use, less cumbersome and has a more pleasing visual appearance. Furthermore, integration of the barrel 3 and the outer housing 14 to form a barrel section 2, provides a barrel section which is significantly larger in diameter than the barrel section 2 of the gas canister air rifle of Figure 2. Therefore, the rifle is able to more closely simulate the physical dimensions of a fire arm such as a centre fire rifle.

It will be appreciated that in further embodiments various modifications to the specific arrangements described above and shown in the drawings may be made. For example, whilst the outer housing 14 is preferably cylindrical, it may alternatively have a square, or any other suitable shape, cross section. Furthermore whilst the outer housing is preferably parallel to the barrel 3 it may be off set and/or at an angle relative to the barrel 3 and barrel axis. In addition the outer housing may also taper along its length, such that the diameter of the outer housing varies along its length. For example the outer housign may have a larger and/or increasing diameter towards the stock end of the rifle, and have a frusto-conical shape. Indeed the outer housing 14 may, in other embodiments taper towards the muzzle end of the barrel 3 such that the diameter of the outer housing at one end corresponds to the diameter fo the barrel with the outer housing 14 then being directly joined to the barrel 3. This would thereby eliminate the need for a front sealing member 16.

It is also contemplated that alternative gas pathways may be provided, other than the gas pathway between the barrel 3 and the inlet adaptor 15 than the specific arrangement described above.

Finally whilst the air gun has been described and shown as an air rifle, and this is the preferred embodiment of the invention, the invention may also be embodied in any gas powered weapon having a barrel, for example in a air pistol.

Claims (14)

1. An air gun comprising: a barrel having an outer diameter; and a gas storage system; wherein the barrel extends within an outer housing such that the outer housing surrounds at least part of the length of the barrel, and the gas storage system comprises a gas chamber defined between the outer housing and the barrel.

2. The air gun of claim 1, wherein the barrel and outer housing are substantially parallel to each other.

3. The air gun of claim 1 or 2, wherein an axis of the barrel is offset from an axis of the outer housing.

4. The air gun of claim 1 or 2, wherein the barrel and the housing are coaxial.

5. The air gun of any preceding claim, wherein the gas chamber extends around the entire circumference of the barrel.

6. The air gun of any preceding claim, wherein the outer housing is cylindrical.

7. The air gun of any one of claims 1 to 5, wherein the outer housing tapers along its length such that the diameter of the outer housing varies along its length.

8. The air gun of any preceding claim, wherein the gas chamber is sealed at a first end by a front sealing member and at a second end by a rear sealing member.

9. The air gun of claim 8, wherein a gas pathway is defined between the rear sealing member and the outer diameter of the barrel.

10. The air gun of claim 9, wherein the air gun further comprises a valve chamber comprising part of an operating action of the air gun.

11. The air gun of claim 10, wherein the gas pathway connects the gas chamber and the valve chamber.

12. The airgun of any preceding claim, wherein the outer housing extends along substantially the entire length of the barrel.

13. The air gun of any preceding claim wherein the air gun is an air rifle.

14. An airgun substantially as hereinbefore described with reference to and/or as shown in the accompanying figures 1 and 3 to 5.