GB2289322A

GB2289322A - Air rifles

Info

Publication number: GB2289322A
Application number: GB9509608A
Authority: GB
Inventors: Graham Bluck
Original assignee: Parker Hale Ltd
Current assignee: Parker Hale Ltd
Priority date: 1994-05-13
Filing date: 1995-05-12
Publication date: 1995-11-15
Anticipated expiration: 2015-05-12
Also published as: GB2289322B; GB9509608D0; GB9409586D0

Abstract

An air rifle includes a cocking lever (60) which is disposed adjacent to the trigger (50) at the underside of the stock (10) and which comprises a forward limb (64) and a rearward limb (62) such that the forward limb (64) may be engaged by the backs of the user's fingers to drive the cocking lever forwardly, and the rearward limb (62) may be engaged by the palm-side of the user's fingers to draw the cocking lever rearwardly, forward movement of the cocking lever (60) after operation of the trigger (50) moving a sliding link (40) rearwardly so as to re-engage an abutment (44) thereon with a shoulder (33) of a striker (30), and subsequent rearward movement of the cocking lever (60) driving the striker (30) forwardly against the force of a compression spring (32) by means of which the striker (30) when released by operation of the trigger (50), is driven to impact on a valve member (15) in order to release a pulse of compressed gas into the barrel (14). The cocking lever also operates a bolt (21) via an extension (66) to load a pellet from a magazine (20). <IMAGE>

Description

Title: "Air Rifles" Description of the invention This invention relates to air rifles of the kind which includes a chamber for a magazine of pellets to be fired, a bolt mechanism for transferring one pellet at a time into the barrel of the rifle and cocking the rifle before firing, a propellant gas reservoir, and a valve mechanism which opens in response to operation of a firing trigger to release a pulse of propellant gas from the reservoir into the barrel so as to fire a pellet located therein. Such air rifles are hereinafter referred to as being "of the kind specified".

Normally the bolt mechanism is so arranged that the user is required to move his hand from the trigger to the bolt mechanism and back to the trigger before firing again. This not only requires a relatively long time interval between successive shots, but is also likely to disturb the user's aim.

It is an object of the invention to provide such an air rifle with an improved bolt mechanism whereby these disadvantages are reduced.

According to the invention we provide an air rifle of the kind specified wherein the bolt mechanism is operatively connected to a cocking lever disposed adjacent to the trigger and so arranged that the user can operate the cocking lever without losing contact with the trigger.

The cocking lever may comprise a two-limbed member having forward and rearward limbs1 the end of one of the limbs of the cocking lever being carried on a pivot at a position adjacent to the trigger, and the forward limb extending towards the trigger so that the user may engage the trigger by means of the index finger with the remaining fingers of the same hand located between the limbs of the cocking lever.

In this way, the cocking lever can be moved forwardly and rearwardly using the remaining fingers of the hand without removing the index finger from the trigger.

Preferably the forward and rearward limbs of the cocking lever are spaced apart by a substantially constant distance and are joined together at one or both ends so that the cocking lever is either of generally U-shape or in the form of a closed loop.

The cocking lever may include an upward arm which is operatively engaged with the bolt so as to drive the bolt rearwardly as the cocking lever is moved forwardly and vice-versa.

The operation of the cocking lever may also set the valve mechanism into a condition wherein operation of the trigger fires the rifle.

Preferably, the valve mechanism is of the knock-open valve type in which a valve member is normally held closed on a seating and is displaced briefly from the seating by the impact of a striker which is released by operation of the trigger.

In this case, the striker may be reset to cock the rifle by means of a slidable link which is connected to said cocking lever so as to drive the striker away from the valve member when the cocking lever is moved rearwardly and hold the striker until the trigger is operated, operation of the trigger causing the slidable link to disengage from the striker.

These and other features of the invention will now be described by way of example with reference to the accompanying drawings wherein: FIGURE 1 is a fragmentary elevation illustrating a preferred form of firing and cocking mechanism in its cocked position; FIGURE 2 is a similar view showing the mechanism in the condition immediately after firing; and FIGURE 3 is a similar view showing the mechanism in an intermediate condition during re-cocking.

As illustrated, a rifle in accordance with the invention includes within a space in the stock 10, a reservoir for either a liquified gas, normally carbon dioxide, or more commonly a compressed gas, normally compressed air, which term will hereinafter be used although it is to be understood that other propellant gasses may be employed. The reservoir may be in the form of a removable rechargeable cylinder, a removable non-rechargeable cylinder, or a non-removable rechargeable vessel formed in the stock.

The compressed air reservoir communicates with a passageway 11 within the body of the rifle, which leads to a valve chamber 12 having a vertical outlet passageway 13, which leads in turn to the rearmost end of the barrel 14.

A valve member 15 is disposed within the valve chamber and is normally closed onto a seating, which may be frusto-conical in form, by means of a compression spring 17 and the pressure of air in the chamber 12. A forward extension 18 of the valve member 15 is guided through a sealing O-ring 29 in a bore in a forward securing block 16 for the valve chamber 12 and is carried by a reduced diameter stem 19 which extends forwardly from the valve seating and the outlet passageway 13, so that when the valve member 15 is displaced out of contact with the seating, air is allowed to flow through the valve chamber 12 around the stem 19, along outlet passageway 13 and into the barrel 14.

The body of the rifle also affords a chamber 20 adapted to receive a self-advancing rotary cartridge of known kind containing a plurality of pellets for firing. A sliding bolt 21 is formed with a fore-end extension 22 which is arranged to penetrate a cartridge received within chamber 20 and an O-ring 23 between the cartridge and the barrel 14, so as to effect a seal. A projection 24 on the extension 22 is adapted to engage and displace a pellet from the cartridge during forward movement of the bolt and deliver such pellet to a position forwardly of the outlet passageway 13, whilst seating it firmly into the rifling of the barrel to form a seal.A plunger 25 is arranged to control the operation of the cartridge by means of a nib 26 which moves into and out of the cartridge in accordance with movement of the plunger 25 through the inter-action of a bevel- edge 27 at the other end of the plunger and a pin 41 as hereinafter described.

A striker 30 is slidable along a bore 31 formed in the body of the rifle, under the force of compression spring 32. It will be noted that the extension 18 of the valve member 15 projects into the bore 31 so as to be engageable by the striker 30 in the manner hereinafter described.

In the cocked position as illustrated in Figure 1, the striker 30 is held against the compression of spring 32 by means of a frusto-conical shoulder 33 which is engaged by an abutment lug 44 formed on a sliding link 40. The sliding link 40 is also pivotal on pin 41, but in the cocked position is prevented from pivoting by the short end of a supporting lever 35 mounted on a fixed pivot 36 and biased into contact with the link 40 by a leaf spring 37. The short end of the lever 35 is in turn prevented from pivoting against the leaf spring 37 by the engagement of its longer tapering rearward end beneath a retaining element comprising a downwardly extending leg 52 formed on the forward end of a trigger 50, which is pivoted on a pin 51 and located at the underside of the rifle.The sliding link 40 is also prevented from rearward movement, which would otherwise be permitted by its pivot pin 41 sliding within a longitudinal slot 42 formed in the body of the rifle, by a blocking member comprising a lever 38 biased by a coil spring 39 and pivoting about pin 34, such that the forward end of it is engaged in a notch 43 formed at the rearward end of the link 40.

In accordance with the invention, an cocking lever 60 is pivotally mounted at the underside of the stock 10 on a fixed pin 61 adjacent to the trigger 50 and comprises a rearward arm 62, curved outer end portion 63 and a forward arm 64 curving back at the upper end to rejoin the rearward arm 62 just behind a trigger guard 65. Alternatively, the forward arm 64 may terminate adjacent to the trigger guard 65.The forward and rearward arms of the cocking lever 60 are curved upwardly and forwardly as shown and so arranged that, in the cocked position as illustrated in Figure 1, the rearward arm 62 is received within a recess formed in the forward end of the pistol grip so that when this is held by the user in the normal manner the user's index finger may rest on the trigger 50 with the remaining fingers of the user's hand disposed within the arcuate space defined by the cocking lever 60.

The cocking lever 60 includes an upward arm 66 which engages an actuating pin 28 carried by the bolt 21. The upward arm 66, at a position intermediate its ends, carries a pivot pin 67 for the rearward end of a connecting link 45 which at its forward end is pivotally connected to the pin 41 which is slidable in the slot 42.

Operation of the trigger 50, against the force of a light biasing spring 53, withdraws the retaining leg 52 from engagement with the rearward end of the supporting lever 35. The force of the compression spring 32 is sufficient to cause the lug 44 to be displaced downwardly through its engagement with the frustoconical face 33 on the striker 30, against the combined forces of leaf spring 37 and coil spring 39, thereby allowing the striker 30 to be projected along the bore 31 so as to strike the exposed end of the extension 18. In so doing it displaces the valve member 15 from its seating releasing air from the reservoir through valve chamber 12 and outlet passageway 13 into the rearward end of the barrel 14 behind the pellet, so as to fire the latter.

It will be understood that the free length of spring 32 is such that after the striker 30 impacts on the extension 18, the spring 32 does not exert a force on the extension 18 sufficient to overcome the force of the spring 17 and the pressure of air in the chamber. Accordingly, the momentum of the striker 30 displaces the valve member 15 momentarily from its seating, but immediately thereafter the valve member 15 is re-engaged with its seating by the force of spring 17, the air pressure acting on it from the chamber 12 side of the valve member 15 and the back pressure caused by the escaping air on the piston formed by the shoulder between the stem 19 and to the extension 18.

In most rifles using a knock-open valve without benefit of a pressure regulated air supply there is a noticeable power curve. This is caused because when the pressure in the reservoir is high, the valve is difficult to knock off its seating and little air is released. As the pressure drops, more air is released and the power rises, until the pressure fails below a level where it can deliver sufficient power. It is usual to utilise the flattest part of the power curve in order to ensure shot-to-shot consistency. The rate of change of reservoir pressure is governed by the amount of air released and the volume of the reservoir, thereby producing a more pronounced power curve.

In order to extract the maximum number of consistent shots from the limited volume reservoir permitted in the butt of the rifle, in accordance with a further feature of the invention a restricter tube 46 is fitted in the outlet passageway 13 to permit a maximum flow of propellant gas sufficient only to produce a certain power level determined by a combination of striker adjustment and restricter diameter. This flattens off the power curve permitting the rifle to work over a wider pressure range without exceeding a pre-set level.This results in a reduction in the wastage of air in the middle of the charge range caused by the heavy striker blow necessary to produce sufficient power at the beginning and end of the charge, because the back pressure caused by the released air acting on the rear of the pellet in the barrel 14, builds up against the restricter 46 and acts on the piston formed by the shoulder between the extension 18 and the stem 19 to accelerate the closure of the valve. This results in the maximum possible number of consistent power shots which will not exceed a pre-set level.

Downward displacement.of the lug 44 on the link 40 in response to operation of the trigger 50 also has the effect of pivoting the supporting lever 35 so as to move the blocking lever 38 against the force of coil spring 39, thereby disengaging the blocking lever 38 from the notch 43 at rearward end of the sliding link 40. Link 40 is then free to slide rearwardly, as illustrated in Figure 2, which shows the mechanism in the condition immediately after filing. It is to be noted that leaf spring 37 acts to maintain the lug 44 in contact with the side face of the striker 30 forwardly of the shoulder 33 due to its pressure on the supporting lever 35.

Whilst the supporting lever 35 is in the position illustrated in Figure 2, the extreme rearward end thereof engages a correspondingly curved face at the forward side of the retaining leg 52 of the trigger to hold the trigger in its retracted position against the force of the associated spring 53, thereby affording a visual indication of the uncocked state of the rifle.

Following operation of the trigger 50, forward movement of the cocking lever 60 to the position illustrated in Figure 3, withdraws the bolt 21 from the cartridge within chamber 20, by the action of the upward arm 66 and its engagement with the actuating pin 28. At the same time, the connecting link 45 is pulled by the pin 67 and it in turn draws the sliding link 40 rearwardly by its action on the common pivot pin 41. At the rear of its stroke, the pin 41 engages the bevelled edge 27 at the lower end of the plunger 25 so as to lift the latter and cause the nib 26 at the upper end thereof in known manner to enter the cartridge to advance the next pellet into alignment with the end of the barrel 14.

At the same time, the lug 44 passes rearwardly of the shoulder 33 so permitting the leaf spring 37 to restore the supporting lever 35 to its original position and thereby lift the forward end of the sliding link 40 and re-engage the lug 44 behind the shoulder 33. When the supporting lever 35 returns to its original position, as illustrated in Figure 3, the trigger 50 returns to its original position by the action of spring 53, so that the retaining leg 52 again holds the supporting lever 35 in a downward position in the manner illustrated in Figure 3.

Subsequent rearward movement of the cocking lever 60 to return it to the-position illustrated in Figure 1 causes the bolt 21 to be advanced and eject a pellet from the cartridge (not shown) in chamber 20 and into the barrel 14.

At the same time, the action of the connecting link 45 drives the sliding link 40 forwardly. Because the rearward end of the supporting lever 35 is held down by the retaining leg 52 of the trigger 50, the lug 44 cannot be displaced downwardly, the forward end of the sliding link 40 being supported by the forward end of the supporting lever 35. As a result, by engagement of the lug 44 with the shoulder 33, forward movement of the sliding link 40 returns the striker 30 to is initial position and places the spring 32 in a state of compression.

At the end of the rearward movement of the cocking lever 60, the forward end of the blocking lever 38 re-engages in the notch 43, under the force of the coil spring 39, and the mechanism is restored to the cocked position as illustrated in Figure 1 ready for re-firing. With the blocking lever 38, re-engaged in the notch 43, the cocking mechanism is locked and can only be unlocked by firing the rifle. This means that once cocked, the mechanism cannot again be cycled and a second pellet fed into the barrel.

Due to the utilisation of the sliding link 40 to cock the striker 30, the hardest part of the cocking action, that of compressing the striker spring 32 is achieved on the rearward stroke of the cocking lever 60, such that pressure must be applied by the padded, palm side of the user's fingers, which is easier and more comfortable than the usual situation with under-lever cocking firearms which cock on the forward stroke with the effort applied by the lesser padded backs of the fingers.

As will be appreciated, the action of the cocking lever 60 to re-load and re-cock the rifle can be accomplished very smoothly, comfortably and quickly without requiring the user to release the trigger and with minimum disturbance to the user's aim in a manner which is not possible with conventional designs.

Also, with appropriate stock design, the rifle is fully ambidextrous in operation.

Claims

ClAIMS:-

1. An air rifle of the kind which includes a chamber for a magazine of pellets to be fired, a bolt mechanism for transferring one pellet at a time into the barrel of the rifle and cocking the rifle before firing, a propellent gas reservoir, and a valve mechanism which opens in response to operation of a firing trigger to release a pulse of propellant gas from the reservoir into the barrel so as to fire a pellet located therein, wherein the bolt mechanism is operatively connected to a cocking lever disposed adjacent to the trigger and so arranged that the user can operate the cocking lever without losing contact with the trigger.

2. An air rifle according to Claim 1 wherein the cocking lever comprises a two-limbed member having forward and rearward limbs, the end of one of the limbs of the cocking lever being carried on a pivot at a position adjacent to the trigger, and the forward limb extending towards the trigger so that the user may engage the trigger by means of the index finger with the remaining fingers of the same hand located between the limbs of the cocking lever.

3. An air rifle according to Claim 2 wherein the forward and rearward limbs of the cocking lever are spaced apart by a substantially constant distance and. are joined together at one or both ends.

4. An air rifle according to Claim 2 or Claim 3 wherein the cocking lever includes an upward arm which is operatively engaged with the bolt so as to drive the bolt rearwardly as the cocking lever is moved forwardly and vice-versa.

5. An air rifle according to any one of Claims 2 to 4 wherein the operation of the cocking lever also sets the valve mechanism into a condition where operation of the trigger fires the rifle.

6. An air rifle according to Claim 5 wherein the valve mechanism is of the knock-open valve type in which a valve member is normally held closed on a seating and is displaced briefly from the seating by the impact of a striker which is released by operation of the trigger.

7. An air rifle according to Claim 6 wherein the striker is re-set to cock the rifle by means of a slidable link which is connected to said cocking lever so as to drive the striker away from the valve member when the cocking lever is moved rearwardly and hold the striker until the trigger is operated, operation of the trigger causing the slidable link to disengage from the striker.

8. An air rifle according to Claim 7 wherein the slidable link affords an abutment adapted to engage behind a shoulder on the striker for the purpose of driving the striker away from the valve member and holding the striker against rearward movement towards the valve member.

9. An air rifle according to Claim 8 wherein the slidable link includes a pivot whereby the abutment can disengage from said shoulder to allow the striker to impact on the valve member, the slidable link normally being held against pivotal movement as required to disengage the abutment from the shoulder by engagement with one end of a supporting lever, the other end of which is held against movement by a retaining element carried by the trigger.

10. An air rifle according to Claim 9 wherein the slidable link is normally held against rearward movement by engagement with a blocking member which is pivotally mounted and bears against said other end of the supporting lever so as to be displaced from engagement with the slidable link when the retaining element is disengaged from said other end of the supporting lever by operation of the trigger.

11. An air rifle according to Claim 10 wherein said other end of the supporting lever is arranged to abut the retaining element in such a manner as to prevent the return of the trigger to its initial position until the supporting lever is returned to its initial position by operation of the cocking lever.

12. An air rifle according to any one of Claims 6 to 11 wherein a flow restricter is interposed between the valve mechanism and the barrel so as to permit a predetermined maximum flow of propellent gas from the reservoir to the barrel.

13. An air rifle according to any one of Claims 6 to 12 wherein the valve member carries, downstream of a co-operating valve seating, an extension which is sealingly received in a bore and is formed with a reduced-diameter stem adjacent to said valve member, whereby a shoulder at the junction between said step and said extension acts as a piston which is exposed to back pressure generated behind a pellet in the barrel to assist in returning the valve member to its closed condition relative to the valve seating.

14. An air rifle having a firing and cocking mechanism substantially as hereinbefore described with reference to and as shown in the accompanying drawings.