GB2184525A - Air rifle - Google Patents

Abstract

A pump action air rifle has a barrel tube 12 housing a pair of barrels 14, (15) mounted side-by-side, the barrels and tube being carried by a receiver 11. Two separate air reservoirs 26 are provided, one for each barrel, each reservoir having its own trigger mechanism 37 arranged to open a piston valve 29 to release air from the reservoir into an individual transfer port 33 leading to one barrel, respectively. Each reservoir is supplied with air under pressure from a single pump cylinder 17 and piston 18, operable by a handle 16, air being delivered to each reservoir from a common supply passage 19 through individual inlet non-return valves 28. <IMAGE>

Description

SPECIFICATION Air rifle This invention relates to air rifles, and also to breech mechanismsforairweapons.

The fundamental operating principle of an air rifle is that a pellet is discharged from the rifle barrel by compressed air. In a great many designs, the com pressed airisgenerated atthe momentofdischarge byaspring-loaded piston andcylinderarrangement, the spring being charged beforehand (for example by a lever mechanism incorporated in the rifle) and the stored energyofthe spring is used to drivethe piston upon pulling ofthetrigger. In an alternative design, the air rifle incorporates a pump mechanism which may be actuated to compress air into a reservoir, a suitable valve arrangement being provided to release that compressed air into the rifle barrel upon pulling ofthetrigger.Both ofthese known designs suffer from the disadvantage that it takes a con siderabletimeto reload the air rifle to discharge a second pellet, following the discharge of a first pellet. This can be a serious problem when the rifle is being usedforsporting purposes: if an animal is wounded by a first pellet but not killed, it may take cover before a second shot can be delivered, so leading to unnecessary suffering bythe animal.

In an attempt to get round this problem, there have been proposalsforair rifles utilising a cylinder of compressed gas of relatively large capacity, a portion only ofthat gas being discharged each time a pelletisfired and the cylinder being detachablefor re-charging remote from the rifle itself. Whilsta second pellet may be discharged much more quickly after a first, nevertheless there is still a considerable delay necessitated by the need to open the breech, insert a second pellet intothe rifle barrel, andthen close the breech again. Afurther disadvantage is that the speed of ejection of a pellet depends upon the state of charge of the compressed gas in the cylinder and so upon the number of pellets discharged following the attachment of a fully-charged cylinder of gas.In turn, this affects the accuracy of the weapon and allowances therefore have to be made when using the sights. Moreover, in certain countries (including the United Kingdom) current legislation may prohibit use of such weapons.

It is a principal object ofthe present invention to provide an air rifle which allows a second pellet to be discharged extremely rapidly after a first pellet and so which substantially overcomes the disadvantages ofthe known designs of air rifle, as outlined above.

Accordingly, one aspect of the present invention provides an air rifle comprising a pair of rifle barrels mounted on a rifle body, a pair of compressed air reservoirs one associated with each barrel respectively and there being a trigger mechanism for each reservoir to enabl e the release of com pressed air therefrom into the breech end of the associated barrel, a single manually-operable air pump mechanism, and meanstodirectaircompressed bythe single pump mechanism to the two reservoirs.

It will be appreciated thatthe air rifle ofthis invention is essentially a double-barrelled air rifle. If how ever such a weapon were produced merely by affix ing togetheron a single stocktwo separate air rifle mechanisms of a known construction, the resultant weapon would be extremely heavy and unwieldy; it would therefore be quite impractical. The arrange ment of the present invention overcomes this pro blem by providing a single air pump mechanism (which constitutes much of the weight of a pump action air rifle design) and two separate air reservoirs, one for each of the two barrels, with suit able means arranged to direct airfrom the pump mechanism to the two reservoirs.Moreover, the dis charge of a pellet from one barrel does not in any way affectthe characteristics of discharge of a pellet from the other barrel.

Conventionally, air rifles are either0.177 or 0.22 calibre and different users havetheirown pre ferences, for their own intended purposes. However, it often happens that in some circumstances (for example long range work) a user may prefer one calibre, but in other circumstances (for example close rangework)the same user may preferthe othercalibre. The air rifle ofthis invention has the significant advantage that the two barrels may be of different calibres, so that a user may have available in the same weapon both (for example) a 0.177 and a 0.22 calibre air rifle.

The means allowing the output from the single air pump to be directed to the two air reservoirs maybe automatic, so charging both reservoirs to the same pressure, or may be manually controlled, so permitting selection of the reservoirwhich isto be char- ged. In the former case, a simple non-return valve at the inletto each reservoirwill suffice, for example comprising a spring-loaded ball engaged with a valve seat formed around an inlet porttothe reservoir, both inlet ports being connected to the pump outlet.

In the case of a selective manual control, a changeovervalve may be provided, which valve is capable of directing air compressed by the air pump mechanism to either one of the two reservoirs. One preferred arrangement has a pair of valve plungers each movable to and from a position where an outlet port from the air pump mechanism is placed in communication with the air reservoir associated with that plunger, an operating arrangement being prov idedtocausetheplungersto move in anti-phase.

Such an operating arrangement may comprise a cam shaft extending transversely across the receiver (main body) ofthe air rifle and having a pair cam profiles, one associated with each valve plunger respectively, wherebyturning movement ofthe cam shaft causes the plungers alternately to be moved to their position where there is communication between the pump mechanism and the reservoir associated with that plunger. If required, the cam shaft may be profiled to enable both plungers simulta nouslyto be moved to their positions where air communication is enabled, so permitting concurrent charging of both reservoirs. This may be advantag emus to permit charging of both reservoirs to preciselythe same air pressure.

Each air reservoirstill may be provided with anon- return valve, at its inlet, so as to relieve the change overvalve means ofairpressureotherthanwhen pumping mistaking place.

The trigger mechanism associated with each air reservoir preferably is arranged such that the operating pressure required forthetrigger mechanism is substantially independent of the air pressure within the reservoir. Conveniently, there is an air transfer passage between the breech end of each barrel and its associated reservoir, a simple piston valve being provided to open the reservoirto thattransfer passage. Pulling thetrigger may bearrangedto release the valve so as to be opened by air pressure within the reservoir.This may be achieved by mounting a slide in the receiver for sliding movementtransverse to the line of movement of the associated piston valve,an abutmentonthe piston being engaged by the slide but the slide having a cut-out portion into which said abutment may be received, to permit op ening ofthe valve. Movement ofthe slide preferably is, for such a configuration, directly controlled bythe trigger.

A user, after discharging a pellet out of one barrel, may wish to recharge the reservoir ofthat barrel, without discharging the reservoir ofthe other barrel.

For safety reasons, it may therefore be advantageous to incorporate an interlock mechanism, to inhibit the discharge of a pellet from a barrel the reservoir associated with which is charged whenever charging of the other reservoir is taking place.

With a pump-action air rifle, it is necessaryfora pellet to be inserted into the bore ofthe barrel from the breech end to an extentsufficientto passtheopening of a transfer passage from the air reservoir into the barrel, in orderthatreleaseoftheairfromthe reservoir may propel the pellet forwardly out ofthe barrel, after closing the breech. One known arrange mentutilisesasealing capfortheendfaceofthe barrel, which cap has a pin adapted to push a pellet inserted into the bore sufficiently far into the barrel as the cap is fitted thereto.Such an arrangement has the disadvantagethatthe cap has to be removed completelyfrom the barrel and so is proneto loss; moreoverthe re-engagement ofthe cap with the barrel is not easy to perform, especially when screw threads are provided. As a result, many pump action air rifles employa side loading arrangement, where a gate is opened in the side of the barrel and a pellet isdroppedsidewaysthroughthegateand is auto- matically pushed forwards as the gate is closed. This arrangement has the disadvantage that very often the pellet turns as it is dropped; if the user does not notice this, the pellet may be pushed into the bore the wrong way round, or worse still, closing ofthe gate may attempt to push the pellet sideways, so completelyjammingihe breech ofthe rifle.

Accordingly, a second aspectofthis invention provides a breech mechanism for a pump action air weapon including a receiver on which is mounted the breech end of the weapon barrel, which breech mechanism comprises a breech block mounted on the receiver for pivoting movement about an axis substantially parallel to the barrel axis between an open postion where access may be gained axially to the breech end of the barrel bore and a closed position where the breech block lies closely adjacentthe breech end face of the barrel, a boltslidably mounted in the breech block for sliding movement between the first position where the breech block may pivot between its said two positions and a second position where the bolt projects into the barrel bore when the breech block is in its closed position, and releasable catch means to retain the bolt in its second position.

It will be appreciated that with the breech mechanism ofthis invention as described above, loading of the barrel with a pellet is performed in a manner closely similarto that associated with many conventional designs of spring-actuated air rifles -that is to say, the breech end ofthe barrel is exposed, and a pellet is directly pushed by the user, axially into the bore. The user may thus be surethatthe pellet is pro perlyinserted,the right way round. Once done, the breech block is pivoted to its closed position so that it lies closely adjacent the breech end face of the barrel, whereafterthe bolt is moved axially so asto enterthe barrel.This action both pushes the pellet forward past a transfer port in the bore ofthe barrel and also serves to maintain the breech block in its closed position, and the releasable catch means serves to hold the bolt in its second position.

Preferably, the bolt is spring-loaded so that subsequent release ofthe catch means following the discharge of a pellet automatically moves the bolt back to its first position, and so permits pivoting movement once more of the breech block to its open position; the weapon may then be re-loaded.

The breech mechanism ofthis invention as described above is applicable equally to an air rifle and an air pistol. Moreover,the breech mechanism especially lends itselfto use in air rifle also ofthis invention and so including a pair of rifle barrels, as has been described hereinbefore. For such a case, the breech blockwould be provided eitherwith a pairofindependent bolts, each having an associated catch means, or preferably the two bolts are mounted on a single carrier itself slidable in the breech block, whereby both bolts are moved simultaneously between theirtwo positions. In this case, only a single catch means is necessary to effect locking of both bolts, simultaneously.

By way of example only, one specific embodiment of air rifle constructed in accordance with this invention and also incorporating a breech mechanism of this invention will now be described in detail, reference being made to the accompanying drawings, in which Figure 1 is a side view of the embodiment of air rifle of this invention; Figure2 is a plan view of the air rifle illustrated in Figure 1; Figure 3 is a partially cut-away detailed view ofthe receiver ofthe air rifle of Figures 1 and 2, with certain parts in a first position; Figure4isaviewsimilarto Figure3,butwithcer- tain parts in another position; ; Figure 5 is a cross-sectional view through there ceiverofthe air rifle of Figures 1 and 2, taken on line V-V marked on Figure 1; Figure 6is a viewfrom one side of the breech block employed in the air rifle of Figures 1 to 5; Figure 7is a viewsimilarto Figure 6, butofthe other side of the breech block; Figure 8 is a partially cut-away plan view of the breech block of Figures 6 and 7; Figure 9 is a sectional view through the breech block, taken on line IX-IX marked on Figure 8; Figure 70 is a view on the breech face ofthe breech block of Figures 6 to 9; Figures 11 and 12 respectively show side and top views of a safety and cocking control rod; and Figure 13 is a sectional view through the control rod, taken to line XIII-XIII marked on Figure 11.

Referring initially to Figures 1 and 2, there is shown a twin-barrel air rifle constructed in accordance with this invention, the rifle comprising a stock 10 attached to a receiver (or main body) 11, there being a barrel tube 12 and a pump mechanism 13 mounted one above the other on the receiver 11. Provided within the barrel tube 12 are twin barrels 14 and 15 (Figure 5) arranged side by side; these barrels may have the same bore diameter (calibre) or may be of different bore calibres, as required. The pump mechanism 13 includes a handle 16, a pump cylinder 17 and a piston 18 (Figure 3) reciprocabletherein upon pivoting movementofthe handle 16; such a pump mechanism is well known and understood in the art and will not be described in further detail here.

Considering the transverse direction of thereceiver 11, the pump mechanism 13 is arranged approximately centrally and there is an outlet passage 19 from the receiver end of the pump cylinder 17, which passage 19 communicates with a valve block 20, also mounted in the receiver. Passage 19 communicates with a transverse passage 21 in the valve block 18, leadingtotwoplungervalveseach havingagrooved plunger 22. The plunger 22 of each valve is slidably mounted in a bore such that the plunger closes off the transverse passage 21 otherthan when the groove in the plunger is aligned with that passage 19.Sliding movement ofthetwo plungers 22 iscontrolled by a cam shaft 23 rotatably mounted in the valve block 18, a lever24 (Figure 4) being provided on the cam shaft externally of the receiver, to permit turning movement of that cam shaft. The cam arran gementissuchthatwhen one plungervalve is open to passage 21, the other valve closes that passage.

Suitable O-ring air seals 25 are provided in association with each plungervalve and the valve block in order to ensure that the overall assembly is properly sealed, notwithstanding the relatively high pressures generated by the pump mechanism 13.

Each barrel has associated therewith an air re reservoir 26 (only one of which is shown in Figures 3 and 4), each air reservoir having an inlet port 27 fitted with a spring loaded non-return ball valve 28. A pas- sage is arranged to communicate between the inlet port 27 and the respective plungervalveforthat barrel, so that the air reservoir may be charged upon opening of the appropriate plungervalve.

At the end of each air reservoir 26 opposed to its inlet port 27, there is provided an air release valve 29 including a valve bush 30, a valve piston 31 and a transfer port 32 leading to atransfer passage 33 in the receiver, communicating with the bore ofthe associated barrel 14 or 15. The valve bush 30 is fitted with O-ring sealsforthe piston 31 to ensure a gas tight seal therebetween, and a flange 40 is affixed to the piston 31,for a purpose to be described below.

The valve piston 31 is maintained in a position where valve 29 is closed by the piston end face remote from the valve bush 30 abutting a spring-loaded trigger slide 34 suitably mounted in a bore in the receiver.

The trigger slide 34 includes an aperture 35 into which the valve piston 31 maymoveunderairpres- sure within the reservoir 26, when aligned therewith.

Aspring 36 urgesthetrigger slide 34 to the position shown in Figure 3, and sliding movement of the slide 34 against the spring bias is performed by pulling a trigger 37, to bring aperture 36 into alignment with the piston 31.A hair-spring 38 urgesthetriggertowards its position shown in Figure 3, abutting a stop pin 39.

Extending transversely across the receiver, above the triggers 37, is a safety and cocking control rod 41, rotatable by means of a side lever42. The rod has a pair of spaced slots 43, a central slot 44 at an angle to slots 43 and a pair of spaced pins 45, as shown in Figures 11 to 13. A leafspring (not shown) engages in central slot 44 to bias the control rod 41 to remain with lever 42 and pins 45 standing generallyvertically; cocking ofthe air release valves 29 is achieved by pushing lever 42 forwardly so that each ofthetwo pins 45 engages a respective flange on the piston 31 of the two air valves, to thrustthetwo pistonsforwardly.On each piston 31 being drivenfullyforwardly, the respective trigger slide 34 moves downwardly so locking the piston 31 in the closed position. Releasing lever 42 allows the rod to return to its central position. In both the central and forward positions, the rod 41 blocks movement of both triggers, as shown in Figure 3.

When air is to be released from at least one ofthe reservoirs 26 by opening the respective air valve 29, achieved by pulling the respective trigger 27, the safety and cocking control rod 41 must first be moved from its central (safety) position rearwardly, so that the two spaced slots 43 are aligned onewith each trigger respectively, as shown in Figure 4. The leaf spring (notshown) will ride out of the central slot 44 as the rod is turned rearwardly, so removing the bias from the rod. When the rod is set in this position, eithertrigger may be pulled, as desired, to move the respective trigger slide 34, the trigger moving into the associated slot 43 in the rod 41.

Though only one air reservoir, valve assembly, and trigger mechanism have been described and are shown in Figures 3 and 4, two such overall assemblies are provided, one for each barrel respectively.

A breech block 50 is pivoted to the receiver by means of a hinge pin 50A, such that the breech block may pivot about an axis parallel to the bores ofthe barrels 14 and 15. The breech block has a breech face 51 which is adapted to liecloselyagainstthecor- responding faces of the two barrels 14 and 15, when the breech block 50 is pivoted to its closed position illustrated in Figures 3 and 4. The breech block may however be pivoted about pin 50Ato its open position, as illustrated in Figure 10, so that access may be gained to the breech faces of the two barrels 14and 15, to permit the insertion of pellets into the barrel bores. When in its closed position, the breech block is sealed to the barrels by means of O-rings appropriately positioned in counterbores in the barrel breech faces.

Slidably mounted in the breech block 50 is a carrier 52 having a keyway 53 engaged by a bolt 54to prevent removal of the carrierfrom the breech block unless the bolt 54 is deliberately extracted. An annular groove 55 is provided around the carrier a lever catch 56 being spring-urged to engagethatgroovewhen the carrier 52 has been pushed into the breech block 40, from the position illustrated in Figures 3,7 and 8 to the position illustrated in Figure 4. Two return springs 57 are provided within the breech block and engaged with the carrier 52, one spring above the other, such that on releasing the lever catch 56 from the annular groove 55, the carrier 52 is moved rearwardly by the springs 57.

The breech block has two bores 58 and 59 corresponding in position to the bores ofthe barreJs 14 and 15,forco-axial alignmenttherewith on move mentofthe breech block41 to its closed position, as illustrated for instance in Figure 4. Mounted on the carrier 52 aretwo pins 60 and 61 slidable along the bores 58 and 59. When the carrier is fully rearward, as limited by the bolt 54 and keyway 53, the pins 60 and 61 are housed wholly within the breech block; but sliding the carrier 52 forwardly to engage lever catch 56 in the groove 55 causes the pins both to pro jectforwardly from the breech face ofthe breech block.Thefree end of each pin 60 and 61 is of a reduced diameter,fora purposeto be described below.

In use, the pump mechanism is operated to charge the reservoirs 26, these being selectively pressurised by actuating lever 24to the appropriate position. Before charging may be commenced, the control rod 41 must be turned to thrustthe pistons 31 forwardly, so closing the airvalves 29 and also cocking the trigger mechanisms. Following charging of both reservoirs, loading ofthe air rifle is completed by releasing the lever catch 56, so permitting the carrier 52 to move rearwardly, pulling the pins 60 and 61 out ofthe two barrels 14 and 15 respectively and then permitting the breech block 50 to pivot about hinge pin 50A, clear of the breech faces of the two barrels.Pellets are inserted one in each barrel and the breech block is moved back to its closed position: this is the state illustrated in Figure 3. The carrier 52 is then thrust forwardly until the lever catch 56engages in the groove 55; in this position, pins 60 and 61 are located in the barrels 14 and 15, so preventing pivoting movement of the breech block. At the same time, the pellets are pushed forwardly bythe pins 60 and 61, and the reduced diameter free ends of the pins lie between the pellets and the transfer passages 33.

In orderto fire the rifle the control rod is turned to its non-safety position, where the slots 43 are aligned with the triggers. One of the triggers may then be pulled to liftthe associated triggerslide 34. Upon the aperture 35 in thetrigger slide coming into register with the end of the associated valve piston 31 ,the piston is moved rearwardly by vi rtue of air pressure withinthe airreservoir, so opening thevalve assembly and permitting air to flow into the barrel, behind the pellet; the pellet is thus driven outofthe barrel. This is the condition illustrated in Figure 4.

After either or both pellets have left the barrel, the pistons 31 as well as the trigger mechanisms may be reset by pushing lever 42 of control rod 41 forwardly: the air reservoir is then ready for recharging, by set tingthe lever 24 to the appropriate position andactuating the pump handle 16 once more.

In an alternative arrangement, the change-over valve mechanism allowing selection ofthe air reservoirto be charged on actuation ofthe pump handle 16 may be eliminated. Instead, the pump may supply air under pressure simultaneously to both air reservoirs, so that both reservoirs will automatically be charged to the same pressure.

Claims (20)

1. An air rifle comprising a pair of rifle barrels mounted on a rifle body, a pair of compressed air reservoirs one associated with each barrel respectively and there being a trigger mechanism for each reservoir to enable the release of compressed airtherefrom into the breech end of the associated barrel, a single manually operable air pump mechanism, and means to direct air compressed by the single pump mechanism to the two reservoirs.

2. An air rifle according to claim 1,whereinthe two barrels have different bore calibres.

3. An air rifle according to claim 1 orclaim 2, wherein a manual control is provided to allowselection oftheairreservoirto be charged bytheoutputof the single pump mechanism.

4. An air rifle according to claim 3, wherein a change-overvalveisarrangedtodirectaircompressed bythe air pump mechanism to either one of the two reservoirs, the change-over valve being operated by the manual control.

5. An air rifle according to claim 4, wherein said change-overvalvehasa pairofvalve plungers each movableto and from a position where an outlet port from the air mechanism is placed in communication with the air reservoir associated with that plunger, an operating arrangement being provided to cause the plungers to move in anti-phase.

6. An air rifle according to claim 5, wherein said operating arrangement comprises a cam shaft extending transversely across the main body of the air rifle and having a pairofcam profiles, one associated with each valve plunger respectively, whereby turning movement of the cam shaft causes the plungers alternately to be moved to their position where there is communication between the pump mechanism and the reservoir associated with that plunger.

7. An air rifle according to claim 1 or claim 2, wherein the output ofthe air pump mechanism is directed to both air reservoirs to allow simultaneous charging thereof, orso that the reservoirwiththe lower air pressure therewithin receives compressed airfrom the pump mechanism.

8. An air rifle according to any ofthe preceding claims, wherein a non-return valve is provided atthe inlet to each reservoir.

9. An air rifle according to claim 8, wherein each non-return valve comprises a spring-loaded ball engaged with a valve seat formed around an inlet port to the reservoir.

10. An air rifle according to any ofthe preceding claims, wherein the trigger mechanism associated with each air reservoir is arranged such that the operating pressure required for the trigger mechanism is substantially independent of the air pressure within the reservoir.

11. An air rifle according to any ofthe preceding claims wherein there is an airtransfer passage between the breech end of each barrel and its associated reservoir, a piston valve being provided to open the reservoir to its transfer passage.

12. An air rifle according to claim 11, wherein a slide is mounted in the receiverfor sliding move menttransverse to the line of movement ofthe associated piston valve, an abutment on the piston being engaged by the slide butthe slide having a cutout portion into which said abutment may be receivedto permit opening ofthevalve.

13. An air rifle according to claim 12, wherein the movement ofthe slide is directly controlled by the trigger.

14. An air rifle according to any ofthe preceding claims, wherein there is provided an interlock mechanism arranged to inhibit the discharge of a pellet from a barrel the reservoir associated with which is charged whenever charging ofthe other reservoir is taking place.

15. An air rifle according to any ofthe preceding claims, wherein there is provided a control leverfor the rifle triggers and air reservoirs, which lever must be moved to a first position in orderto allowchar- ging ofthe reservoirs to take place, and must be moved to a second position in order to allow either trigger mechanism to be actuated.

16. An air rifle substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.

17. A breech mechanism for a pump action air weapon including a receiver on which is mounted the breech end oftheweapon barrel,which breech mechanism comprises a breech block mounted on the receiverfor pivoting movement about an axis substantially parallel to the barrel axis between an open position where access may be gained axially to the breech end ofthe barrel bore and a closed position where the breech block lies closely adjacent the breech end face of the barrel, a bolt slidably mounted in the breech blockforsliding movement between the first position where the breech block may pivot between its said two positions and a second position where the bolt projects into the barrel bore when the breech block is in its closed position, and releasable catch means to retain the bolt in its second position.

18. A breech mechanism according to claim 17, wherein the bolt is spring-loaded so that release of the catch meansfollowingthedischargeofapellet automatically moves the bolt back to its first position.

19. A breech mechanism for a pump action air weapon, which breech mechanism is constructed substantially as hereinbefore described, with referenceto and as illustrated in the accompanying drawings.

20. An air rifle according to any of claims 1 to 16, whenever incorporating a breech mechanism ac cording to anyofclaimsl7to 19.