POWER CONTROL ASSEMBLY FOR AN AIRGUN AND METHOD OF ASSEMBLING A POWER CONTROL ASSEMBLY

Abstract

A power control assembly (295) for an air gun (205) comprising: a power control element (271) having a longitudinal axis and a forward and a rearward end, the power control element (271) having a helical groove (271g) formed around a portion of a length thereof from a first longitudinal position to a second longitudinal position, the first and second longitudinal positions being axially spaced from respective forward and rear ends of the power control element (271) such that the groove (271g) has forward and rearward ends; an intermediate collar element (281) arranged to form a collar around the power control element (271); and a power control dial (291) arranged to form a collar around the intermediate collar element (281), wherein the intermediate collar element (281) has first and second radial through-holes (281a1, 281a2) axially spaced along a longitudinal axis of the assembly (295) such that when the collar element (281) is placed around the power control element (271) the through-holes (281a1, 281a2) intersect the groove (271g) at respective locations thereof longitudinally spaced apart.

Claims

1. A power control assembly for an air gun the power control assembly comprising: a power control element having a longitudinal axis and a forward and a rearward end, the power control element having a helical groove formed around a portion of a length thereof from a first longitudinal position to a second longitudinal position, the first and second longitudinal positions defining ends of the helical groove, the power control assembly being arranged such that forward and rearward ends of the helical groove limit longitudinal travel of the power control element an intermediate collar element arranged to form a collar around the power control element and a power control dial arranged to form a collar around the intermediate collar element, wherein the intermediate collar element has first and second radial through-holes axially spaced along a longitudinal axis of the power control assembly such that when the intermediate collar element is placed around the power control element the first and second radial through-holes intersect the helical groove at respective locations thereof that are longitudinally spaced apart.

2. The power control assembly as claimed in claim 1, further comprising a gripping portion disposed in each respective first and second radial through-hole of the intermediate collar element and the helical groove of the power control element such that longitudinal movement of the intermediate collar element relative to the power control element is constrained by the gripping portion to follow a helical path defined by the helical groove.

3. The power control assembly according to claim 2, wherein the power control dial is arranged to confine the gripping portion within each respective first and second radial through-hole of the intermediate collar element and the helical groove.

4. The power control assembly according to claim 2, wherein the gripping portion within each respective first and second radial through-hole comprises at least one ball bearing.

5. The power control assembly according to claim 4, wherein the gripping portion within each respective first and second radial through-hole comprises a plurality of ball bearings arranged in a substantially linear radial row.

6. The power control assembly according to claim 1, further comprising a hammer element and a compression spring element constrained between the hammer element and power control element, the power control dial being arranged to adjust a longitudinal position of the power control element thereby to adjust an amount of compression of the spring element against the hammer element.

7. A pneumatic air gun comprising the power control assembly according to claim 6.

8. The pneumatic air gun according to claim 7, wherein the power control dial is exposed on each of left and right sides of the pneumatic air gun.

9. The pneumatic air gun according to claim 7, wherein the power control dial is exposed on each of left and right sides of the pneumatic air gun by means of an aperture formed in each of left and right hand faces of a housing of the air gun.

10. A method of assembling a power control assembly for an air gun, the method comprising: providing a power control element having a longitudinal axis and a forward and a rearward end, the power control element having a helical groove formed around a portion of a length thereof from a first longitudinal position to a second longitudinal position, the power control assembly being arranged such that the forward and rearward ends of the helical groove limit longitudinal travel of the power control element; providing an intermediate collar element arranged to form a collar around the power control element; and providing a power control dial arranged to form a collar around the intermediate collar element, whereby the intermediate collar element has first and second radial through-holes axially spaced along a longitudinal axis of the power control assembly, the method further comprising placing the intermediate collar element around the power control element whereby the first and second radial through-holes intersect the helical groove at respective locations thereof that are longitudinally spaced apart.

11. The method as claimed in claim 10, further comprising providing a gripping portion in each respective first and second radial through-hole of the intermediate collar element and the helical groove of the power control element such that longitudinal movement of the intermediate collar element relative to the power control element is constrained by the gripping portion to follow a helical path defined by the helical groove.

12. The method according to claim 11, further comprising providing the power control dial around the intermediate collar element so as to confine the gripping portion within each respective first and second radial through-hole of the intermediate collar element and the helical groove.

13. The method according to claim 11, whereby providing a gripping portion comprises providing a gripping portion within each respective first and second radial through-hole, the gripping portion comprising at least one ball bearing.

14. The method according to claim 13, further comprising providing a gripping portion within each respective first and second radial through-hole, the gripping portion comprising a plurality of ball bearings arranged in a substantially linear radial row.

15. The method according to claim 10, further comprising providing a hammer element and a compression spring element constrained between the hammer element and power control element and providing the power control dial to adjust a longitudinal position of the power control element thereby to adjust an amount of compression of the spring element against the hammer element.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0057] One or more embodiments of the invention will now be described, by way of example only, with reference to the accompanying figures in which:

[0058] FIG. 1 shows an example of a known pneumatic air gun;

[0059] FIG. 2 shows a pneumatic air gun according to an embodiment of the present invention;

[0060] FIG. 3 is a schematic cross-sectional illustration of a portion of the pneumatic air gun of FIG. 2;

[0061] FIG. 4 is a schematic illustration of a portion of the pneumatic air gun of FIG. 2;

[0062] FIG. 5 is an enlarged view of a power control arrangement of the embodiment of FIG. 2;

[0063] FIG. 6 is an enlarged view of the power control arrangement of the embodiment of FIG. 2 showing a direction of rotation of a power control dial to increase a power of the air gun;

[0064] FIG. 7 is an enlarged view of the power control arrangement of the embodiment of FIG. 2 showing a direction of rotation of a power control dial to decrease a power of the air gun;

[0065] FIG. 8 shows a rear portion of the power control dial of the pneumatic air gun of FIG. 2 showing a rotational indexing arrangement of the dial;

[0066] FIG. 9 shows a power control element and intermediate collar element of the air gun of FIG. 2 in (a) exploded view and (b) partially assembled view;

[0067] FIG. 10 shows a further stage in the assembly of a valve activating mechanism (a) before and (b) after a pair of ball bearings are fed into each of a pair of respective through-holes in the intermediate collar element;

[0068] FIG. 11 illustrates a further stage in the assembly of the valve activating mechanism in which the power control element and intermediate collar element are inserted into an aperture formed in the power control dial 291 (a) before and (b) after insertion;

[0069] FIG. 12 illustrates a further stage in the assembly of the valve activating mechanism in which a grub screw element is inserted through a radial through-hole formed in the power control dial, (a) before and (b) after the grub screw is fitted;

[0070] FIG. 13 illustrates a geometry and internal detail of the power control assembly shown in FIG. 12(b), and shows (a) a side view of the power control assembly, (b) an end view of the power control assembly looking in the direction of arrow A shown in FIG. 13(a), (c) a cross-sectional view along line C-C of FIG. 13(e), (d) a cross-sectional view along line A-A of FIG. 13(a), and (e) a cross-sectional view along line B-B of FIG. 13(b); and

[0071] FIG. 14 illustrates a geometry and internal detail of the power control assembly shown in FIG. 12(b), and shows (a) a side view of the power control assembly, (b) an end view of the power control assembly looking in the direction of arrow A shown in FIG. 14(a), (c) a cross-sectional view along line C-C of FIG. 14(e), (d) a cross-sectional view along line A-A of FIG. 14(a), and (e) a cross-sectional view along line B-B of FIG. 14(b).

[0072] FIG. 2 shows an air gun 205 according to an embodiment of the present invention. Like features of the air gun 205 of FIG. 2 to the known air gun 5 of FIG. 1 are shown with like reference numerals incremented by 200. FIG. 2(a) shows the gun 205 in side view with a power control dial 291 (FIG. 2(b)) visible. FIG. 2(b) is an enlarged view of a rearward portion A of the air gun 205 showing the power control dial 291. The power control dial 291 protrudes through an aperture or window 291W formed through housing 205h of the air gun 205 (FIG. 2(b)), enabling access by a user to view and rotate the dial 291 from both left and right sides of the air gun 205.

[0073] An arrangement by which the air gun 205 releases (or fires) a projectile 246, by means of a release valve 110, is shown in FIG. 3.

[0074] As shown in FIG. 3, the air gun 205 has a pressure chamber 120 that is in fluid communication with air reservoir 216 of the gun. The pressure chamber 120 has an interior volume 121. The pressure chamber 120 has an outlet port 122. An airflow passage 130 connects the outlet port 122 to a breech 240. The breech 240 forms part of a barrel 242. A release valve 110 controls release of air from the pressure chamber 120. The release valve 110 comprises a valve stem 112 and a valve head 114 which can form a seal against the outlet port 122. The release valve 110 is configured to move between a closed (sealed) state in which the valve seals against the outlet port to prevent a flow of compressed air to the barrel 242 and an open state in which the valve is spaced from the outlet port to allow a flow of compressed air to the barrel 242 to fire a projectile 246. FIG. 3 shows the valve 110 in the closed state. The valve 110 is operated by a valve activating mechanism 260 applying a force to the valve stem 112 in direction 118. When the valve 110 is opened, air can flow along the airflow passage 130 to the breech 240. Air flows around the valve stem 112.

[0075] In the arrangement shown, the airflow passage 130 is an L shaped passage with a first portion 130A which surrounds the valve stem 112 and a second portion 130B which is orthogonal to the valve stem 112 and the barrel 242.

[0076] Force is applied to the valve stem 112 in direction 118 by a hammer element 261, in order to open the valve 110. The hammer element 261 is biased to move in the direction of arrow 118 by a coil spring element 263 although other forms of biasing element may be useful in some embodiments. The coil spring element 263 is held in a compressed condition against the hammer element 261 by means of an adjustable power control element 271. The position of the power control element 271 may be moved in a direction toward or away from the hammer element 165 (direction Y) in order to adjust an amount of compression of the spring element 263 by means of a power control dial 291 (FIG. 2, FIG. 5) described in more detail below. The amount of compression of the spring element 263 adjusts the rate at which the hammer element 261 moves towards the valve stem 112, thereby adjusting the speed at which the release valve 110 opens and releases gas from the pressure chamber 120. The greater the compression of the spring element 263, the faster the rate at which the release valve 110 releases gas, and the greater the amount of power imparted to projectile 146 to fire the projectile 146 from the pneumatic air gun 5.

[0077] The hammer element 261 is held in its cocked position, as shown in FIG. 3, by means of a release catch 265. In the example illustrated, the release catch 265 is moved in the direction of arrow X in order to release the hammer element 261 from the cocked position. The release catch 265 is moved by means of an electromagnetic actuator under the control of an electronic gun control unit (GCU) 250 (FIG. 4) described below. The release catch 265 is so moved when a user pulls the trigger 206 of the air gun 205 (FIG. 2). In some alternative arrangements the release catch 265 is moved in the direction of arrow X by means of a mechanical linkage arrangement when the trigger 206 is pulled.

[0078] As described above, in the embodiment of FIG. 2, the trigger 206 is operatively connected to valve activating mechanism 260 by an electrical/electronic valve activating mechanism having an electromagnetic actuator. The trigger 206 provides an input signal 251 to the GCU 250 as shown in FIG. 4. The GCU 250 outputs a control signal to the valve activating mechanism 260. When the valve activating mechanism 260 is energised, release catch 265 moves in the direction of arrow X, and the spring element 263 urges hammer element 261 in the direction of arrow 218 to strike the valve stem 112, moving the release valve 110 to the open position. This controls an air-pulse packet applied to the breech 240 to fire the projectile 146.

[0079] FIG. 5 is a schematic illustration of the arrangement by which the amount of power imparted to a projectile 146 fired from the air gun 205 may be adjusted.

[0080] As described above, the valve activating mechanism 260 has a hammer element 261 that is urged towards the valve stem 112 of release valve 110 by means of a spring element 263. Power control dial 291 adjusts the amount of compression of the spring element 263 by moving adjustable power control element 271 towards or away from the spring element 263. In the embodiment of FIG. 2, the power control element 271 has a cylindrical shape and is provided with a helical groove 271g around an outer surface thereof. The helical groove may be considered to function as a screw thread although in the illustrated embodiment it is in the form of a groove formed in the power control element 271 and not a ridge protruding from the element 271. The helical groove is closed at forward and rearward ends 271g1, 271g2 thereof. The ends are located at respective first and second longitudinal positions or locations 271g1, 271g2 along the power control element 271. In the arrangement shown the ends are axially spaced from respective forward and rearwards ends of a body portion 271b of the power control element 271 (see below).

[0081] The power control element 271 is coupled to the power control dial 291 by means of an intermediate collar element 281. The power control element 271, intermediate collar element 281 and power control dial 291 are substantially coaxial with a common longitudinal axis LA that is along a length of the gun, substantially parallel to a longitudinal axis of the barrel 242 in the embodiment of FIG. 2.

[0082] In the illustrated embodiment, the power control dial 291 has an outer diameter of 30 mm, the intermediate collar element has a diameter of 19.7 mm and the power control element 271 has a diameter of 10.5 mm. It is to be understood that other sizes may be useful in some embodiments. For example, in some embodiments the power control dial 291 may have an outer diameter of 25 mm, the intermediate collar element may have a diameter of 15 mm and the power control element 271 may have a diameter of 8 mm. Other sizes may be useful, larger or smaller than these dimensions.

[0083] The power control dial 291 surrounds the intermediate collar element 281 and is fixedly coupled thereto. The power control dial 291 and intermediate collar element 281 are provided in a correspondingly shaped recess 291r formed in the housing 205h or chassis of the gun 205. The recess 291r allows rotation of the dial 291 and collar element 281 but substantially prevents movement thereof in a longitudinal direction. This forces the power control element 271 to move along the longitudinal direction when the dial 291 is turned as described herein. The power control dial 291 is exposed on left and right hand sides of the gun 205 as shown in FIG. 2, allowing a user to rotate the dial 291 by means of their finger from either side of the gun 205. In some embodiments the power control dial 291 may be exposed on only one of the left and right hand sides of the gun 205, allowing a user to rotate the dial 291 by means of their finger from only one side of the gun 205.

[0084] As described in further detail below, the power control element 271 has a body portion 271b and a nose portion 271n of reduced diameter forward of the body portion 271b. The power control element 271 has a recess 271r formed in the body portion 271b therein forward of the helical groove 271g, arranged to receive a portion of a guide element 282. In the embodiment of FIG. 2 the guide element is in the form of a ball bearing 282 such that around half of the ball bearing is exposed to protrude beyond an outer surface of the body portion 271b. Other arrangements may be useful, for example the ball bearing may protrude by a different amount, sufficient to act as a guide to prevent axial rotation of the power control element 271 with respect to the housing 205h or chassis of the gun 205 (see below). Other forms of guide element may also be useful, such as in the form of an elongate rod element that fits in the recess 271r. The use of a ball bearing 282 facilitates relatively smooth movement of the power control element 271 without rotation about axis LA.

[0085] A slider element 283 is provided in the housing 205h of the gun 205 forward of the power adjuster dial 291, being held within the housing 205h such that the slider element cannot rotate or move laterally or longitudinally with respect to a longitudinal axis of the gun 205, said axis being substantially parallel to the longitudinal axis of the barrel 242. The slider element has an aperture 283a formed therethrough having a longitudinal axis substantially coincident with that of the slider element 283, and in which the power control element 271 sits with its longitudinal axis LA substantially coincident with that of the slider element 283. The power control element 271 is slidable through the slider element 283. The aperture 283a has a longitudinal groove 283g formed in a wall thereof arranged to receive the ball bearing 282 provided in recess 271r of the power control element 271. Interference of the ball bearing with the groove 283g prevents rotation, about the longitudinal axis LA, of the power control element 271 relative to the slider element 283 (and therefore a housing 205h of the gun 205). Rather, the slider element 283 in cooperation with the guide element 282 allows only relative longitudinal motion between the slider element 283 and power control element 271.

[0086] As illustrated schematically in FIG. 6, rotation of the power control dial 291 in an anticlockwise direction (as viewed from a rear of the gun 205 looking in a forward direction parallel to the barrel 242) causes the power control element 271 to move towards the hammer element 261, applying a greater force or thrust to the spring element 263, further compressing the spring element 263 and increasing the power imparted to the projectile 146 when the gun 205 is fired. Conversely, as illustrated in FIG. 7, rotation of the power control dial 291 in a clockwise direction causes the power control element 271 to move away from the hammer element 261, reducing compression of the spring element 263 and decreasing the power imparted to the projectile 146 when the gun 205 is fired.

[0087] FIG. 8 illustrates a rear portion of the valve activating mechanism 260 and shows a rearward end of the power control element 271, intermediate collar element 281 and power control dial 291. As shown in FIG. 8, the rear surface of the collar element 281 is provided with a circumferential series of recesses or dimples 281d around and adjacent an outer radial edge of the collar element 281. A spring plunger portion 281 is provided, fixed relative to the housing 205, and having a plunger in the form of a ball bearing trapped within a body of the spring plunger portion 281. A spring of the spring plunger portion 281 urges the plunger outwardly and into a dimple 281d of the collar element 281. When the collar element 281 is rotated by a user, by rotation of the power control dial 291, the plunger is urged rearwardly against the action of the spring of the spring plunger portion 281, thereby resisting rotation of the power control dial 291. Rotation of the power control dial 291 is thereby indexed, enabling a user to select a predefined rotational position of the power control dial 291 according to indicia provided on a radially outer circumferential side surface of the dial 291 visible to a user as shown in FIG. 2(b). The resistance to rotation of the power control dial 291 provided by the spring plunger portion 281 may be selected so as to be sufficient to maintain the dial 291 in a position set by a user during the course of expected operational conditions of the gun 205.

[0088] Assembly and operation of the components permitting adjustment of the power of the gun 205 will now be described with reference to FIG.'s 9 to 14.

[0089] FIG. 9(a) is an exploded view of a portion of the air gun 205 showing the power control element 271 and the intermediate collar element 281. As noted above, the power control element 271 has a helical groove 271g formed along a portion of a body portion 271b of the element 271. The power control element 271 also has a cylindrical nose portion 271n of smaller diameter than the body portion 271b and provided forward of the body portion 271b with respect to the gun 205. The nose and body portions 271n, 271b share a common longitudinal axis LA. The nose portion 271n is of a diameter slightly smaller than an inner diameter of the spring element 263 and is arranged to pass through a portion of the spring element 263 such that the spring element 263 abuts a shoulder 271s of the power control element 271 formed where the nose portion 271n meets the body portion 271b. In the embodiment of FIG. 2, a circumferential recess 271c is formed in a face of the shoulder 271s, radially inward of an outer peripheral surface of the body portion 271b, into which a free end of the spring element 263 may sit thereby to reduce radial movement of the free end of the spring element 263 against the shoulder 271s. The spring element 263 is shown in dashed outline in FIG. 9(a).

[0090] The intermediate collar element 281 has an aperture 281ap therethrough along a cylinder axis thereof, arranged to receive the power control element 271 therethrough. A pair of radial through-holes 281a1, 281a2 are provided through a wall of the collar element 281 at radially opposite surfaces of the collar element 281. The through-holes are displaced with respect to one another along the longitudinal (cylinder) axis of the collar element 281 so as to expose the groove 271g formed in the outer surface of the power control element 271. A blind hole 282a1 is also formed in to the outer wall of the intermediate collar element 281 arranged to receive an end portion of a screw, to secure the power control dial 291 to the intermediate collar element 281 (see below).

[0091] FIG. 9(b) shows the power control element 271 and intermediate collar element 281 in a partially assembled state with the power control element 271 inserted through the intermediate collar element 281 such that the power control element 271 and collar element 281 are coaxial, and the respective through-holes 281a1, 281a2 meet the groove 271g formed in the outer surface of the power control element 271 thereby to expose the groove 271g.

[0092] FIG. 10(a) shows a further stage in the assembly of the valve activating mechanism 260 in which gripping portions in the form of respective pairs of ball bearings 282 are fed into each of the respective through-holes 281a1, 281a2. FIG. 10(b) shows the power control element 271 and intermediate collar element 281 after the ball bearings 282 have been fed into the through-holes 281a1, 281a2. The radially inner bearings 282 sit partially in the groove 271g and partially within the respective through-hole 281a1, 281a2, trapping the collar element 281 such that longitudinal motion of the collar element 281 relative to the power control element 271 is possible only if the power control element 271 and collar element 281 are rotated relative to one another about the longitudinal axis, such that the gripping portions 282 slide along the helical groove 271g. This arrangement is illustrated in FIG. 13(e), described below.

[0093] The groove 271g is formed along only a portion of the length of the power control element 271 and terminates before the groove 271g reaches respective opposite ends of the element 271. Accordingly, the groove 271g may be described as closed. Thus, relative rotation of the power control element 271 and collar element 281 is limited in a given direction by the closed ends of the groove 271g.

[0094] An advantage of the present invention is that the ball bearings 282 may be fitted to the intermediate collar element 281 after the collar element 281 has been fitted to the power control element 271. This allows the groove 271g or thread to be provided with closed ends, i.e., the thread terminates short of the opposed ends of the body portion of the power control element 271. The closed ends allow a limit to be imposed on the rotation of the wheel, so that linear movement of the power control element 271 has a defined stroke that cannot be exceeded.

[0095] FIG. 11 illustrates a further stage in the assembly of the valve activating mechanism 260 in which the power control element 271 and intermediate collar element 281 are inserted into an aperture 291ap formed in the power control dial 291. The power control dial 291 has a radial through-hole 291a1 formed through a wall thereof, the through-hole 291a1 being aligned with a threaded blind hole 282a1 formed in the intermediate collar element 281. In some embodiments the hole 282a1 may be a through-hole.

[0096] FIG. 12 illustrates a further stage in the assembly of the valve activating mechanism 260 in which a grub screw element 293 is inserted through the radial through-hole 291a1 formed in the power control dial 291 to engage the threaded radial hole 282a1 of the intermediate collar element 281, thereby securing the intermediate collar element 281 to the power control dial 291. Consequently, rotation of the power control dial 291 causes rotation of the intermediate collar element 281, which in turn causes axial translation of the power control element 271 as described above with respect to FIG.'s 5 to 7. The assembled power control element 271, intermediate collar element 281 and power control dial 291 substantially as shown in FIG. 12(b) may be referred to as a power control assembly 295.

[0097] FIG. 13 illustrates the geometry and internal detail of the power control assembly 295 shown in FIG. 12(b). FIG. 13 and FIG. 14 are scale drawings; however, it is to be understood that the dimensions of the components may be varied and the relative sizes of components and of proportions of components may be varied within suitable ranges within the scope of the present invention. That is, variations in component size and relative proportions may be made whilst still achieving the technical advantages of the present invention as herein described. The illustrated embodiments are provided for illustrative purposes and the invention is to be understood as defined in the aforementioned statements of invention and the appended claim set.

[0098] FIG. 13(a) is a side view of the power control assembly 295. FIG. 13(b) is an end view of the power control assembly 295 looking in the direction of arrow A of FIG. 13(a). The geometry is illustrated with the power control element 271 at a rearward limit of longitudinal travel corresponding to minimum compression of the spring element 263, rearward being with respect to a longitudinal length of the groove 271g, towards a rear of the air gun 205. In the embodiment shown the word MIN is marked on the radially outer surface of the power control dial 291 at a position such that a user sees the word MIN through the aperture 291W in the side of the housing 205h of the air gun 205 with the power control element 271 in its rearmost position (FIG. 2(b)).

[0099] FIG. 13(c) is a cross-sectional view along line C-C of FIG. 13(e). An end portion of the helical groove 271g formed in the outer surface of the power control element may be seen in the figure. The figure shows the power control arrangement 295 at a limit of travel of the power control element 271 in the rearward direction corresponding to minimum compression of the spring element 263, with radially inner ball bearing 282 in through-hole 281a1 abutted against a forward end of the helical groove 271g.

[0100] FIG. 13(d) is a cross-sectional view along line A-A of FIG. 13(a).

[0101] FIG. 13(e) is a cross-sectional view along line B-B of FIG. 13(b).

[0102] FIG. 14(a) is also a side view of the power control assembly 295. FIG. 14(b) is an end view of the power control assembly 295 looking in the direction of arrow A of FIG. 14(a). The geometry is illustrated with the power control element 271 at a forward limit of longitudinal travel corresponding to maximum compression of the spring element 263. In the embodiment shown the word MAX is marked on the radially outer surface of the power control dial 291 at a position such that a user sees the word MAX through the aperture 291W in the side of the housing 205h of the air gun 205 205 with the power control element 271 in its forwardmost position (FIG. 2(b)).

[0103] FIG. 14(c) is a cross-sectional view along line C-C of FIG. 14(e). An end portion of the helical groove 271g formed in the outer surface of the power control element 271 may be seen in the figure. The figure shows the power control arrangement 295 at a limit of travel of the power control element 271 in a forward direction corresponding to maximum compression of the spring element 263, with radially inner ball bearing 282 in through-hole 281a2 abutted against a rearward end of the helical groove 271g. As described above, the helical groove 271g is a closed groove having forward and rearward ends or end limits, terminating short of free ends of the body portion 271b of the power control element 271. This enables the free ends to act as limits or end stops to forward and rearward movement of the power control element 271 with respect to the housing 205h and power control dial 291.

[0104] FIG. 14(d) is a cross-sectional view along line A-A of FIG. 14(a).

[0105] FIG. 14(e) is a cross-sectional view along line B-B of FIG. 14(b).

[0106] In the embodiment shown the radially outer surface of the power control dial 291 is marked with numerals 1 to 18 at equal angular intervals between the MIN and MAX indicia, at radial positions corresponding to the radial positions of the dimples 281d formed in the rear face of the intermediate collar element 281. It is to be understood that other indicia may be used such as other alphanumerical characters, words, symbols, colours. Other numbers of indicia may be useful.

[0107] Embodiments of the present invention have the advantage that precise control of the amount of compression of the spring element 263 may be achieved by a user in a reproducible manner. Thus, a user may select an amount of compression of the spring element 263 according to the numerical indices displayed on the power control dial 291 according to the shot the user is taking at a given moment in time. It is to be understood that, by varying a length of the threaded groove 271g, an amount of desired travel of the power control element 271 may be selected by a manufacturer for a given product.

[0108] Embodiments of the present invention provide a more robust and precise means for controlling the power of a shot compared with known solutions. Embodiments of the present invention provide enhanced flexibility for manufacturers in designing and manufacturing high quality power control arrangements. The amount of compression of the spring element 263 may be varied by varying the axial length of the helical groove 271g. The rate at which compression of the spring element 263 is achieved for a given angular rotation of the power control dial 291 may be varied according to a pitch of the helical groove 271g, being an axial length of the groove 271g for a given angular rotation of the power control element 271.

[0109] Some embodiments of the present invention also facilitate more rapid assembly of precision components, since the power control arrangement may in some embodiments be assembled as a module ready for installation into the housing 205h of the air gun 205. Furthermore, in some embodiments a jig is not required for assembly of the power control arrangement 295, reducing assembly time and the costs associated with assembly. As described herein the gripping portions, in the present embodiment in the form of respective pairs of ball bearings, may be conveniently fitted after the intermediate collar element 281 has been placed over the power control element 271 and before coupling to the power control dial 291. The power control assembly 295 may subsequently be installed in the housing 205h.

[0110] Throughout the description and claims of this specification, the words comprise and contain and variations of the words, for example comprising and comprises, means including but not limited to, and is not intended to (and does not) exclude other moieties, additives, components, integers or steps.

[0111] Throughout the description and claims of this specification, the singular encompasses the plural unless the context otherwise requires. In particular, where the indefinite article is used, the specification is to be understood as contemplating plurality as well as singularity, unless the context requires otherwise.

[0112] Features, integers, characteristics, compounds, chemical moieties or groups described in conjunction with a particular aspect, embodiment or example of the invention are to be understood to be applicable to any other aspect, embodiment or example described herein unless incompatible therewith.