A REAR SIGHT ADAPTER AND METHOD OF USE THEREOF

[0001] The present invention relates to an adjustable rear sight for a firearm. More specifically, the present invention concerns an adapter for an adjustable rear sight that is adjustable for windage and/or elevation.

BACKGROUND

[0002] Iron sights are a system of shaped alignment marks used as sighting devices to assist in the aiming of a device, such as, e.g., a firearm, a crossbow or a telescope, and which exclude the use of optics as in reflector sights, holographic sights and telescopic sights.

[0003] Generally, iron sights include a rear sight and a front sight, which together are aligned relative to one another along a line of sight to aim a device at a target.

[0004] The rear sight is usually adjustable in a left and right direction relative to the line of sight, also known as windage, to compensate for any horizontal deviation of a projectile trajectory from an intended point of impact. Likewise, the rear sight is usually also adjustable in an up and down direction relative to a line of sight, also known as elevation, to compensate for any vertical deviation of a projectile trajectory from the intended point of impact.

[0005] Typically, windage and elevation adjustments are affected by respective threaded adjustment screws that may move a rear sight in a corresponding direction relative to the device. Usually, the adjustment screws allow the sight to move a certain angular distance with each degree of rotation.

[0006] A problem in general with such adjustable sights is that there is an inherent degree of error in the adjustment mechanisms due to imperfections and looseness in the engagement between a threaded shaft of an adjustment screw and its corresponding threaded bore and respective moving parts of the sight. This degree of error adversely impacts the accuracy of the sight.

[0007] The above problem is further pronounced when the sighting systems are used with firearms, such as, e.g., rifles and pistols, where backlash, slop or wear in the threaded engagement can exacerbate any inaccuracies.

[0008] Current solutions for addressing these problems include the use of tightening screws and the like for applying a force to a side of an adjustment screw to enhance its threaded engagement with its corresponding threaded bore in the adjustable sight. However, such solutions normally push the adjustment screw out of alignment creating wear and resistance and resulting in further inaccuracies with the sight. Further, the force applied by the tightening screw or the like gradually reduces over time resulting in the adjustable sight vibrating or falling out of adjustment.

[0009] Another problem in general with adjustable sights is that once assembled and machined there is currently no way to change a rotational direction of an adjustment screw or thread direction, profile and/or ratio of an adjustment screw without extensive re-machining of sight parts.

SUMMARY OF INVENTION

[0010] Embodiments of the present invention provide an adapter for a rear sight, a rear sight including the adapter and methods of use thereof, which may at least partially address one or more of the problems or deficiencies mentioned above or which may provide the public with a useful or commercial choice.

[0011] According to a first aspect of the present invention, there is provided an adapter for a rear sight for a firearm including: a threaded sleeve configured to be at least partially received in a threaded bore of a sight body of the rear sight for adapting the bore to centrally receive a threaded shank of a windage or elevation adjustment screw.

[0012] According to a second aspect of the present invention, there is provided a rear sight for a firearm including: at least one sight body configured to be adjustably mounted to the firearm, said sight body having a threaded bore and at least one guide bore, and operatively associated with a rear sighting element for visual alignment by a user with a front sighting element separately mounted to the firearm; at least one guide rail configured to be received through the at least one guide bore for slidably mounting the at least one sight body relative to the firearm; an adjustment screw for moving the at least one sight body along the guide rail, said adjustment screw having a distal end, an opposed head and a threaded shank extending therebetween; and an adapter including a threaded sleeve and configured to be at least partially received in the threaded bore of the at least one sight body for interfacing a threaded engagement between the threaded shank of the adjustment screw and the threaded bore and adapting the threaded bore to centrally receive the threaded shank.

[0013] Advantageously, the adapter of the present invention enhances the accuracy of a rear sight of a firearm by centrally aligning a threaded shaft of an adjustment screw and thereby removing or at least reducing any backlash, slop or wear in the threaded engagement between the adjustment screw and a respective sight body of the rear sight. The centring ability is further enhanced in embodiments of the adapter, wherein a flange portion of the adapter is received in a complementary-shaped recess defined in the sight body to secure the adapter in a straight axial plane when threadingly engaged with the sight body.

[0014] The adapter of the present invention further advantageously enables a rear sight to be readily altered or adjusted without the need for extensive re-machining. For example, sight bodies with sight apertures of differing radiuses may be readily substituted by using the adapter to adapt the threaded bore of the respective sight bodies to receive the threaded shaft of the associated adjustment screw. Also, the thread direction, profile and/or ratio of the adjustment screws may advantageously be readily changed by using the adapter to adapt the respective sight bodies of the rear sight to threadingly engage with a desired thread direction, profile and/or ratio of a replacement adjustment screw.

[0015] As indicated above, the rear sight and adapter of the present invention are primarily for use with firearms, preferably rifles. It will therefore be convenient to hereinafter describe the rear sight and adapter with reference to this example application as a rear sight and adapter for a firearm. However, a person skilled in the art will appreciate that the adapter and rear sight are capable of broader applications and applicable to other aimed, ranged weaponry and devices.

[0016] The firearm may include any barrelled range weapon intended to be carried and used by an individual. For example, the firearm may include a pistol, a revolver, a rifle, a shotgun, a carbine, a machine gun, a sniper rifle, a submachine gun, an automatic rifle, an assault rifle, or a battle rifle. Preferably, the firearm may include a rifle.

[0017] The firearm may generally include an action, a stock and a barrel.

[0018] The action may include a bolt, hammer and trigger assembly and may usually lie midway along the firearm. The action may be configured to load a cartridge, strike it with the hammer and expel the spent shell of the cartridge.

[0019] The stock may be the rear part of the firearm and may be intended to assist a shooter in stabilising the firearm, aiming the firearm and countering recoil from the action when a shot is fired. The “butt” of the stock may be the rearmost end of the stock intended to be in contact with a shoulder of a shooter when a round is fired.

[0020] The barrel may be a metal tube extending from the action and configured to receive and guide a bullet propelled out of the action towards a target. The barrel may usually include internally machined spiral grooves configured to give a bullet a spinning motion when fired to stabilise the bullet in flight. An outer end of the barrel may usually be referred to as the “muzzle”.

[0021] Typically, the firearm may be aimed by aligning rear and front sighting elements along a line of sight at a target.

[0022] The rear sighting element may form part of the rear sight. The rear sighting element may be a notch or groove or the like, or an aperture sight, preferably the latter.

[0023] The rear sight may be mounted by a firearm mount in a dovetail on the barrel or receiver, frame or slide of the firearm close to the eye of a shooter.

[0024] The front sighting element may usually be mounted on an outer end of the barrel of the firearm. The front sighting element may include a post, a bead, a ramp or a ring protruding from an upper surface of the barrel.

[0025] As used herein, the term “windage” may refer to sight adjustment used to compensate for horizontal deviation of a projectile trajectory from its intended point of impact, preferably rear sight adjustment.

[0026] The rear sight may be adjusted for windage by moving the sight laterally in a horizontal direction relative to the firearm and a line of sight. Typically, the rear sight may be adjusted for windage by moving the rear sight horizontally in a direction towards a direction of the horizontal deviation of the projectile trajectory from its intended point of impact.

[0027] As used herein, the term “elevation” may refer to sight adjustment used to compensate for vertical deviation of a projectile trajectory from its intended point of impact, preferably rear sight adjustment.

[0028] The rear sight may be adjusted for elevation by moving the rear sight vertically relative to the firearm and a line of sight. Typically, like with for windage, the rear sight may be adjusted for elevation by moving the rear sight vertically in a direction towards a direction of the vertical deviation of the projectile trajectory from its intended point of impact.

[0029] The rear sight may be of any suitable size, shape and construction and may be formed from any suitable material or materials. Generally, the rear sight may be formed from a durable material or materials, such as, e.g., plastic or metal material or materials, preferably metal, more preferably steel. [0030] The rear sight may be of unitary construction or may be formed from two or more rear sight pieces, typically the latter.

[0031] The rear sight may include at least one sight body configured to be adjustably mounted to the firearm, at least one guide rail for slidably mounting the at least one sight body relative to the firearm and an adjustment screw for moving the at least one sight body along the at least one rail, preferably back-and-forth for adjusting the windage of the rear sight.

[0032] The at least one sight body may be of any suitable size, shape and construction, preferably solid construction. For example, the at least one sight body may be a sphere, a pyramid, a triangular prism, a cube, a rectangular prism, a pentagonal prism, a hexagonal prism, an octagonal prism or, generally, of a polyhedron shape.

[0033] Typically, the at least one sight body may have cuboidal or rectangular prism shape. The body may be defined by a plurality of walls. The walls may be curved or linear.

[0034] In preferred embodiments, the sight body may have a base wall, an opposed top wall, a pair of opposed end walls and a pair of opposed sidewalls extending longitudinally between the opposed end walls.

[0035] The body may include rounded corners extending between adjacent sidewalls and end walls. Similarly, the body may include rounded, chamfered or bevelled edges between the top wall and/or base wall and adjacent end walls and/or sidewalls, preferably chamfered edges between the base wall and the sidewalls.

[0036] The body may have a longitudinal axis extending between the opposed end walls. The body may be configured to be mounted, or oriented, relative to the firearm such that the longitudinal axis extends substantially parallel to a line of sight.

[0037] The body may be adjustably mounted to the firearm in any suitable way so as to be adjustable for windage and/or elevation, preferably detachably.

[0038] The body may include the rear sighting element, preferably integrally formed with the sight body. The rear sighting element may be in the form of a sight aperture or bore extending between and through the opposed end walls of the body, preferably centrally positioned relative to the opposed sidewalls at or near the base wall when the sight body is mounted to the firearm.

[0039] The body may be slidably mounted on the at least one guide rail, preferably a pair of guide rails. [0040] The guide rails may extend substantially parallel to one another across an upper surface of the firearm so that the body may be slidably moveable in a lateral direction across the firearm relative to a line of sight for adjusting the windage of the rear sight.

[0041] The guide rails may be of any suitable size, shape and construction. Typically, the rails may each include a pair of opposed ends and an elongate body extending therebetween, preferably linearly. Each rail may be of tubular or solid construction and may have any suitable cross-sectional shape, preferably solid with a circular cross-section.

[0042] As indicated, the body may include at least one guide bore for receiving the at least one guide rail therethrough and slidably mounting the body to the at least one guide rail. Preferably, the body may include a pair of guide bores.

[0043] The guide bores may extend between and through the opposed sidewalls of the body, preferably in a linear orientation perpendicular to the longitudinal axis of the body. The guide bores may each be sized and shaped to freely receive a guide rail therethrough.

[0044] As indicated, the rear sight includes an adjustment screw for moving the at least one sight body back-and-forth along the guide rail for adjusting windage.

[0045] The adjustment screw may be of any suitable size, shape and construction and may be formed from any suitable material or materials, typically metal material or materials, preferably steel.

[0046] The adjustment screw may include a distal end configured to be inserted into a corresponding threaded bore, an opposed head and a threaded shank extending therebetween, preferably linearly.

[0047] The threaded shank may include an external thread extending at least partially along a length of the threaded shank. The external thread may have any suitable thread profile and ratio. For example, the external thread may have a square, triangular, trapezoidal or other profile shape. Typically, the threaded shank may have a screw thread profile with trapezoidal outlines, preferably an Acme thread form or trapezoidal metric thread form.

[0048] The head of the adjustment screw may include an enlarged head or knob or the like to assist in manual rotation of the adjustment screw by a shooter. In this regard, the enlarged head or knob may include knurling.

[0049] As indicated, the at least one sight body may include a threaded bore for receiving the adjustment screw therethrough. The threaded bore may extend between and through the opposed sidewalls of the body, preferably in a linear orientation perpendicular to the longitudinal axis of the body. The threaded bore may be sized and shaped to freely receive the screw therethrough, preferably without threaded engagement.

[0050] The threaded bore may include an internal thread extending at least partially along a length of the bore. Like with the threaded shank, the internal thread may have any suitable thread profile and ratio, typically a screw thread profile with trapezoidal outlines, preferably an Acme thread form or trapezoidal metric thread form.

[0051 ] The threaded bore and the threaded shank of the adjustment screw may preferably threadingly engage with one another via the adapter.

[0052] In use, the at least one sight body may be moved along the at least one guide rail for adjusting the windage by rotation of the adjustment screw along its longitudinal axis. Rotation of the adjustment screw may allow the sight body to move a precise angular distance with each degree of rotation.

[0053] The adjustment screw and the guide rails may extend substantially parallel to one another across the firearm.

[0054] In preferred embodiments, the adjustment screw and the guide rails may together form part of a windage arm assembly.

[0055] The windage arm assembly may be of any suitable size, shape and construction for supporting the adjustment screw and the guide rails in a substantially parallel arrangement extending across the firearm and the at least one sight body mounted thereto.

[0056] The assembly may further include a pair of opposed mounting elements between which the adjustment screw and the guide rails may extend. The adjustment screw may be rotatably coupled to the mounting elements to enable the screw to rotate about its longitudinal axis. In preferred embodiments, the head of the adjustment screw may protrude through an outer mounting element for manual rotation of the adjustment screw by a shooter.

[0057] In some embodiments, the rear sight may further include an elevation arm assembly interconnecting the windage arm assembly (and the at least one sight body mounted thereto) and the firearm mount for mounting the rear sight to the firearm. The elevation arm assembly may provide for elevation adjustments of the rear sight.

[0058] The elevation arm assembly may include a second sight body slidably mounted on second pair of guide rails arranged in a substantially vertical orientation between a second pair of opposed mounting elements and a second adjustment screw for moving the second sight body up-and-down along the second pair of guide rails, preferably for adjusting the elevation of the rear sight.

[0059] The second sight body may be of similar construction to the at least one sight body described above with the exception that it may not include a sight aperture.

[0060] The second sight body may preferably correspond to one of the pair of opposed mounting elements of the windage arm assembly.

[0061] The second pair of guide rails and the second adjustment screw may be of similar or identical construction as previously described.

[0062] Likewise, the second sight body may include a pair of guide bores and a threaded bore for respectively receiving the pair of guide rails and at least the threaded shank of the second adjustment screw therethrough.

[0063] The threaded bore of the second sight body and the threaded shank of the second adjustment screw may preferably threadingly engage with one another via the adapter.

[0064] In use, the second sight body and thus the windage arm assembly and the at least one sight body may be moveable up and down along the second pair of guide rails for adjusting elevation by rotation of the second adjustment screw along its longitudinal axis. Rotation of the second adjustment screw may allow the windage arm assembly and the at least one sight body to move a precise angular distance with each degree of rotation.

[0065] The second pair of guide rails and the second adjustment screw may extend substantially parallel to one in a vertical orientation substantially perpendicular to a line of sight of the firearm. The guide rails and the second adjustment screw may extend between the opposed mounting elements. The second adjustment screw may be rotatably coupled to the mounting elements to enable the screw to rotate about its longitudinal axis.

[0066] In preferred embodiments, the head of the second adjustment screw may protrude through an uppermost mounting element for manual rotation of the adjustment screw by a shooter.

[0067] The lowermost mounting element of the elevation arm assembly may be operatively associated with the firearm mount. The firearm mount may be of any form or construction known in the art. [0068] As indicated, the rear sight includes an adapter configured to be at least partially received in the threaded bore of a sight body to adapt the bore to centrally receive the threaded shank of an adjustment screw.

[0069] The adapter may be of any suitable size, shape and construction and may be formed from any suitable material or materials.

[0070] Generally, the adapter may be formed from a durable material or materials, such as, e.g., plastic or metal material or materials, preferably metal, more preferably brass.

[0071] The adapter may be of unitary construction or may be formed from two or more adapter pieces, preferably the former.

[0072] The adapter may include a pair of opposed ends and at least one sidewall extending longitudinally therebetween and defining a central conduit. The central conduit may be sized and shaped for receiving a threaded shank of an adjustment screw therethrough.

[0073] The at least one sidewall is curved such that the adapter has a circular profile shape defining the sleeve.

[0074] The opposed ends may include an insertion end configured to be at least partially inserted into a threaded bore and an opposed outer end.

[0075] The at least one sidewall may have a pair of opposed surfaces extending substantially parallel to one another. The opposed surfaces may include an inner surface and an opposed outer surface.

[0076] The outer surface of the adapter may include an external thread defined thereon for threadingly engaging with the internal thread of a threaded bore of a sight body. The external thread may extend at least partially along a length of the adapter, preferably about a collar portion at or near the outer end.

[0077] The external thread may have any suitable thread direction, profile and ratio for at least partially complementing a thread direction, profile and/or ratio of the threaded bore. For example, the external thread may have a square, triangular, trapezoidal or other profile shape. Typically, the threaded shank may have a screw thread profile with trapezoidal outlines, preferably an Acme thread form or trapezoidal metric thread form.

[0078] Advantageously, the external thread may enable the adapter to be axially adjustable relative to the threaded bore. [0079] Likewise, the inner surface of the adapter may include an internal thread defined thereon for threadingly engaging with the threaded shank of an adjustment screw received through the central conduit. The internal thread may extend at least partially along a length of the adapter.

[0080] Again, the internal thread may have any suitable thread direction, profile and ratio for at least partially complementing a thread direction, profile and/or ratio of the threaded shank of the adjustment screw. For example, the external thread may have a square, triangular, trapezoidal or other profile shape. Typically, the threaded shank may have a screw thread profile with trapezoidal outlines, preferably an Acme thread form or trapezoidal metric thread form.

[0081] The adapter may adapt a threaded bore for centrally receiving the threaded shank of an adjustment screw in any suitable way, preferably such that the central axes of the threaded bore and the threaded shank substantially co-align.

[0082] For example, in some embodiments, the adapter may adapt the threaded bore to centrally receive the threaded shank by decreasing a diameter of the threaded bore, typically such that the threaded shank is snugly and centrally received therethrough.

[0083] In other embodiments, the adapter may include one or more guide members that at each at least partially extend towards the central conduit for centrally positioning a threaded shank received therethrough relative to the threaded bore.

[0084] In yet other embodiments, at least a portion of the adapter at or near the insertion end may taper or at least partially taper in diameter to centrally position the threaded shank relative to the threaded bore. In such embodiments, the narrowing diameter of the central conduit may centrally position a threaded shank received therethrough relative to the threaded bore.

[0085] In yet further embodiments, at least an insertion end portion of the adapter may taper or at least partially taper in diameter and may be at least partially split defining two or more guide members for centrally positioning a threaded shank of an adjustment screw received therethrough relative to the threaded bore.

[0086] In such embodiments, the two or more guide members may extend at least partially inwards relative to the central conduit due to the tapering and may assist in centrally positioning the threaded shank relative to the threaded bore. The two or more guide members may collectively urge or bias the threaded shank into a central alignment.

[0087] In such embodiments, the insertion end portion of the adapter may include one, two, three, four or even five or more splits. Each split may extend at least partially along a length of the adapter towards the outer end, preferably entirely. Each split may extend in a spiral or linear arrangement or orientation between the insertion end and the outer end, preferably linearly in an orientation parallel to a longitudinal axis of the adapter.

[0088] Advantageously, the one or more splits in the adapter, apart from defining two or more guide members for centrally positioning a threaded shank, may additionally facilitate in insertion of the adapter into the threaded bore.

[0089] In some embodiments, the outer end of the adapter may include a flange portion. The flange portion may extend radially outwards from the outer end to an outer flange edge, preferably in a direction substantially perpendicular to a longitudinal axis of the adapter.

[0090] The flange portion may extend at least partly about a periphery of the outer end, preferably entirely.

[0091] The flange portion may at least partially abut against a side surface of a sight body when the adapter is inserted into a threaded bore.

[0092] Advantageously, the flange portion may prevent over insertion of the adapter into the threaded bore.

[0093] In some embodiments, the side surface of the sight body may include a recess about an outer opening of the threaded bore for at least partially receiving the flange portion therein. The recess may be a shaped recess, preferably shaped to complement a shape of the flange portion.

[0094] As indicated above, the external thread of the adapter enables the adapter to be axially adjustable relative to a threaded bore. Rotation of the adapter may allow axial adjustment of the adapter relative to the threaded bore, preferably incremental axial adjustment.

[0095] In some embodiments, the adapter may further include a retaining member or mechanism or part thereof for retaining the adapter in an axial position relative to the threaded bore.

[0096] Any suitable retaining member or mechanism may be used that is able to selectively prevent rotation of the adapter relative to the threaded bore and thus axial movement of the adapter relative to the threaded bore.

[0097] For example, in some embodiments, a first part of a retaining mechanism may be associated with the adapter and a second part of the retaining mechanism connectable to the first part may be associated with the threaded bore.

[0098] The retaining mechanism may include a threaded connection, an interference fit (snap fit) connection or a bayonet-type connection, for example.

[0099] The retaining mechanism may include a male formation engaging a female formation.

[00100] For example, in some embodiments, the adapter may have a male formation of the retaining mechanism that engages, or mates, with a female formation of the retaining mechanism associated with the threaded bore for retaining the adapter in place.

[00101] Conversely, in other embodiments, the adapter may have a female formation of the retaining mechanism that engages, or mates, with a male formation of the retaining mechanism associated with the threaded bore for retaining the adapter in place.

[00102] In some embodiments, the retaining mechanism may include a detent biased to extend outwardly from the outer surface of the sidewall of the adapter and a receiving hole defined in a sidewall of the threaded bore for engaging the detent to retain the adapter in place.

[00103] In such embodiments, the detent may be biased to extend outwardly via the presence of the threaded shank received in and/or through the central conduit.

[00104] The detent may have an angled or sloped outer end to guide and facilitate disengagement of the detent from the receiving hole when the threaded shank is removed, or partially removed, from the central conduit.

[00105] In other embodiments, the retaining member or mechanism may include a retention fastener configured to be received through a groove or opening defined in the flange portion of the adapter and into a corresponding retention opening defined in the sidewall of the sight body.

[00106] In such embodiments, the flange portion of the adapter may include a plurality of openings and/or grooves defined thereon in a spaced arrangement at least partially about the flange portion. The grooves may preferably be defined in the outer flange edge.

[00107] The adapter may include any suitable number of openings and/or grooves. For example, the adapter may include two, three, four, five, six, seven, eight, nine, ten, eleven, twelve or more openings and/or grooves defined in the flange portion.

[00108] Each opening or groove and the corresponding retention opening defined in the sight body may be configured to be co-aligned and receive the retention fastener therethrough for preventing rotation of the adapter relative to the sight body and thus retaining the adapter in place.

[00109] The retention fastener may be any suitable type of fastener. For example, the retention fastener may be a pin or threaded fastener.

[00110] In some embodiments, the retention fastener may have a tool engaging formation, such as, e.g., a socket, formed in its head for receiving a tool for applying torque to the fastener and turning or rotating the retention fastener.

[00111] In other embodiments, the retention fastener may include an enlarged head to assist in the application of manual torque by a shooter’s hand, for example. The enlarged head may include a winged head.

[00112] The corresponding retention opening defined in the sidewall of the sight body may be adjacently located and extend substantially parallel to the threaded bore.

[00113] In preferred embodiments, the retention opening and the threaded bore may share a common sidewall.

[00114] In such embodiments, insertion of the retention fastener into the retention opening may press or urge the common sidewall outwards and away from the retention opening to applying a clamping or circumferential force on the adjacent threaded bore to at least partially further assist in retaining the adapter in place.

[00115] In some embodiments, the sidewall of the sight body may include more than one retention opening for each receiving a retention fastener. For example, the sidewall may include two, three, four, five, six or more retention openings. The retention openings may preferably be arranged about the threaded bore in a spaced arrangement.

[00116] According to a third aspect of the present invention, there is provided a method of enhancing the accuracy of a rear sight for a firearm, said method including: fitting an adapter at least partially into a threaded bore of a sight body of the rear sight for adapting the threaded bore to centrally receive a threaded shank of a windage or elevation adjustment screw.

[00117] According to a fourth aspect of the present invention, there is provided a method of altering a rotational direction of a windage or elevation adjustment screw of a rear sight for a firearm, said method including: disassembling the rear sight by removing the windage or elevation adjustment screw from a first side of a threaded bore extending entirely through a sight body of the rear sight; fitting an adapter at least partially into an opposed second side of the threaded bore of the sight body for adapting the threaded bore to receive the windage or adjustment screw from the second side; and re-assembling the rear sight by at least partially inserting a threaded shank of the windage or elevation adjustment screw into an adapted said threaded bore of the sight body from the second side and thereby altering the rotational direction of the windage or elevation adjustment screw.

[00118] According to a fifth aspect of the present invention, there is provided a method of altering a sight radius of a rear sight for a firearm, said method including: disassembling the rear sight by removing a windage or elevation adjustment screw from a threaded bore extending entirely through a sight body of the rear sight; fitting an adapter at least partially into a threaded bore of a replacement sight body having a sight aperture of a desired radius for adapting the threaded bore of the replacement sight body to receive the windage or elevation adjustment screw; and re-assembling the rear sight by at least partially inserting a threaded shank of the windage or elevation adjustment screw into an adapted said threaded bore of the replacement sight body.

[00119] According to a sixth aspect of the present invention, there is provided a method of altering a thread direction, profile and/or ratio of a windage or elevation adjustment screw of a rear sight for a firearm, said method including: disassembling the rear sight by removing the windage or elevation adjustment screw from a threaded bore extending entirely through a sight body of the rear sight; fitting an adapter at least partially into a threaded bore of the sight body for adapting the threaded bore to at least partially receive a replacement windage or elevation adjustment screw having a desired thread direction, profile and/or ratio; and re-assembling the rear sight by at least partially inserted a threaded shank of the replacement windage or elevation adjustment screw into an adapted said threaded bore of the sight body.

[00120] The methods of the third, fourth, fifth and sixth aspects may include one or more features or characteristics of the rear sight and/or adapter as hereinbefore described.

[00121] The disassembling may typically further include removing the sight body from the at least one guide rail or pair of rails. [00122] The fitting may preferably include threadingly inserting the adapter into an inlet opening of the threaded bore, typically such that the external thread of the adapter threadingly engages with the internal thread of the threaded bore.

[00123] The inlet opening may be the opening of the threaded bore configured to receive the threaded shank of the adjustment screw therethrough.

[00124] The adapter may be threadingly inserted into the inlet opening of the threaded bore until a desired axial position relative to the threaded bore is achieved, typically until the flange portion of the adapter is in abutment with a sidewall of the sight body.

[00125] A retaining member or mechanism of the adapter may then be engaged to selectively prevent any further rotation of the adapter relative to the threaded bore.

[00126] An adapter may be fitted that preferably has desired thread characteristics, including thread direction, profile and/or ratio for at least partially complementing the replaced adjustment screw or sight body, while centrally positioning the threaded shank of the adjustment screw relative to the threaded bore.

[00127] The re-assembling may include re-fitting or fitting the sight body on the at least one guide rail or pair of guide rails, preferably prior to threadingly engagingly the sight body with the threaded shank of the adjustment screw via the adapter.

[00128] Any of the features described herein can be combined in any combination with any one or more of the other features described herein within the scope of the invention.

[00129] The reference to any prior art in this specification is not, and should not be taken as an acknowledgement or any form of suggestion that the prior art forms part of the common general knowledge.

BRIEF DESCRIPTION OF DRAWINGS

[00130] Preferred features, embodiments and variations of the invention may be discerned from the following Detailed Description which provides sufficient information for those skilled in the art to perform the invention. The Detailed Description is not to be regarded as limiting the scope of the preceding Summary of Invention in any way. The Detailed Description will make reference to a number of drawings as follows:

[00131] Figure 1 is a photograph showing a rear sight according to an embodiment of the present invention fitted to a firearm; [00132] Figure 2 is a line drawing showing an upper perspective view of a sight body of a rear sight for a fire arm according to an embodiment of the present invention;

[00133] Figure 3 is a line drawing showing an upper perspective view of an adapter according to an embodiment of the present invention for use with the sight body as shown in Figure 2;

[00134] Figure 4 is a line drawing showing a sectional view of the sight body as shown in Figure 2;

[00135] Figure 5 is a photograph showing a retention fastener for use with the sight body as shown in Figures 2 and 4 and the adapter as shown in Figure 3;

[00136] Figure 6 is a flow chart showing steps in a method of enhancing the accuracy of a rear sight for a firearm according to an embodiment of the present invention;

[00137] Figure 7 is a flow chart showing steps in a method of altering a rotational direction of a windage or elevation adjustment screw of a rear sight for a firearm according to an embodiment of the present invention;

[00138] Figure 8 is a flow chart showing steps in a method of altering a sight radius of a rear sight for a firearm according to an embodiment of the present invention; and

[00139] Figure 9 is flow chart showing steps in a method of altering a thread direction, profile and/or ratio of a windage or elevation adjustment screw of a rear sight for a firearm according to an embodiment of the present invention.

DETAILED DESCRIPTION

[00140] Figures 1 to 5 show a rear sight (100), an adapter (200) and parts thereof for use with a rifle (1000; i.e., a firearm) according to an embodiment of the present invention.

[00141] Referring to Figure 1 , the rear sight (100) includes an eyepiece block (110; i.e., a sight body) having a sight aperture (112), a threaded bore (114) and a pair of guide bores (116).

[00142] The eyepiece block (110) is slidably mounted to a windage arm assembly (120) including a pair of guide rails (130) and a windage adjustment screw (140) extending substantially parallel to one another across the rife (1000) perpendicular to a line of sight.

[00143] The pair of guide rails (130) and the windage adjustment screw (140) extend between a pair of mounting elements (122), including an elevation block (152) slidably mounted to an elevation arm assembly (150). [00144] The pair of guide rails (130) are received through the respective guide bores (116) of the eyepiece block (110) for slidably mounting the eyepiece block (110) to the windage arm assembly (120) and the rifle (1000).

[00145] The windage adjustment screw (140) is for moving the eyepiece block (110) back- and-forth along the rails (130) for adjusting the windage of the rear sight (100).

[00146] The screw (140) includes a distal end (not visible), an opposed head with associated knob (142) and a threaded shank (144) extending therebetween. The associated knob (142) assists in manual rotation of the adjustment screw (140) by a shooter.

[00147] The windage adjustment screw (140) is received through the threaded bore (114) of the eyepiece block (110) and threadingly engages with the threaded bore (114) via the adapter (200), which interfaces the threaded engagement and adapts the bore (114) to centrally receive the threaded shank (144).

[00148] The elevation arm assembly (150) interconnects the windage arm assembly (120) (and the eyepiece block (110) mounted thereto) and the rifle mount (not shown) for mounting the rear sight (100) to the rifle (1000). The elevation arm assembly (150) provides for elevation adjustments of the rear sight (100).

[00149] The elevation arm assembly (150) includes the elevation block (152), a pair of guide rails (160) and an elevation adjustment screw (170) extending substantially parallel to one another in a substantially vertical orientation immediately beside the rife (1000) perpendicular to a line of sight.

[00150] The pair of guide rails (160) and the elevation adjustment screw (170) extend between another pair of mounting elements (122), including a lowermost mounting element (122A) that is operatively associated with the rifle mount (not shown).

[00151] The elevation block (152) is of a similar construction to the eyepiece block (110) and has a threaded bore (114) and a pair of guide bores (116).

[00152] The pair of guide rails (160) are received through the respective guide bores (116) of the elevation block (152) for slidably mounting the elevation block (152) to the elevation arm assembly (150) and the rifle (1000).

[00153] The elevation adjustment screw (170) is for moving the elevation block (152) up- and-down along the rails (160) for adjusting the elevation of the rear sight (100). The screw (170) includes a distal end (not visible), an opposed head with associated knob (172) and a threaded shank (174) extending therebetween. The associated knob (172) assists in manual rotation of the adjustment screw (170) by a shooter.

[00154] The elevation adjustment screw (170) is received through the threaded bore (114) of the elevation block (152) and threadingly engages with the threaded bore (114) via the adapter (200), which interfaces the threaded engagement and adapts the bore (114) to centrally receive the threaded shank (174).

[00155] In use, the eyepiece block (110) of the rear sight (100) is adjusted for windage and elevation by rotating the respective windage adjustment screw (140) and elevation adjustment screw (170). Rotation of the screws (140, 170) allows the eyepiece block (110) to move precise angular distances with each degree of rotation.

[00156] Referring to Figure 2, the eyepiece block (110) is formed from steel and is of solid construction.

[00157] The block (110) is defined by a plurality of walls, including a base wall (111), an opposed top wall (113), opposed end walls (115) and an opposed sidewalls (117) extending longitudinally between the opposed end walls (115) and defining a longitudinal axis.

[00158] The block (110) includes chamfered edges between the base wall (111) and the opposed sidewalls (117) and between the top wall (113) and the opposed end walls (115).

[00159] The block (110) is configured to be mounted, or oriented, relative to the rifle (1000; not shown) such that the longitudinal axis extends substantially parallel to a line of sight of the rifle (1000; not shown).

[00160] As shown, the sight aperture (112) extends between the through the opposed end walls (115) and is centrally positioned relative to the opposed sidewalls (117) at or near the base wall (111).

[00161] The pair of guide bores (116) for respectively receiving the guide rails (130; not shown) for slidably mounting the eyepiece block (110) to the rifle (1000; not shown) extend between the through the opposed sidewalls (117) of the block (110). The bores (116) extend in a linear orientation perpendicular to the longitudinal axis of the block (110). The bores (116) are sized and shaped to each freely receive a guide rail (130; not shown) therethrough.

[00162] The threaded bore (114) for receiving a threaded shank (144) of the windage adjustment screw (140) therethrough also extends between and through the opposed sidewalls (117) of the block (110). The bore (114) extends in a linear orientation perpendicular to the longitudinal axis of the block (110). The bore (114) is sized and shaped to freely receive the screw (140) therethrough without threaded engagement.

[00163] The threaded bore (114) includes an internal thread extending at least partially along a length of the bore (114). The internal thread may have any suitable thread direction, profile and ratio.

[00164] Referring to Figure 3, the adapter (200) is configured to be received in the threaded bore (114; not shown) of the eyepiece block (110; not shown) and elevation block (152; not shown) to centrally receive a threaded shank (144, 177; not shown) of an adjustment screw (140, 170; not shown) therethrough.

[00165] The adapter (200) is of unitary construction and is formed from brass.

[00166] The adapter (200) includes a pair of opposed ends and a curved sidewall (202; i.e., at least one sidewall) extending longitudinally therebetween and defining a longitudinal axis. The curved sidewall (202) defines a central conduit (210) and a circular profile shape of the adapter (200). The central conduit (210) is sized and shaped for receiving the threaded shank (144, 177; not shown) of an adjustment screw (140, 170; not shown) therethrough.

[00167] The opposed ends include an insertion end (204) configured to be at least partially inserted into a threaded bore (114; not shown) and an opposed outer end (206).

[00168] The curved sidewall (202) includes an inner surface (203) and an opposed outer surface (205).

[00169] The outer surface (205) of the adapter (200) include an external thread (220) defined thereon for threadingly engaging with the internal thread of a threaded bore (114; not shown) of the eyepiece block (110; not shown) or elevation block (152; not shown).

[00170] The external thread (220) is located about a collar portion at or near the outer end (206).

[00171] The external thread (220) may have any suitable thread direction, profile and ratio for at least partially complementing a thread direction, profile and/or ratio of a threaded bore (114; not shown).

[00172] Advantageously, the external thread (220) enables the adapter (200) to be axially adjustable relative to a threaded bore (114; not shown).

[00173] Likewise, the inner surface (203) of the adapter includes an internal thread (not visible) defined thereon for threadingly engaging with the threaded shank (144, 174; not shown) of an adjustment screw (140, 170; not shown) received through the central conduit (210).

[00174] Again, the internal thread may have any suitable thread direction, profile and ratio for at least partially complementing a thread direction, profile and/or ratio of the threaded shank (144, 174; not shown) of an adjustment screw (140, 170; not shown).

[00175] An insertion end portion (204A) of the adapter (200) tapers in diameter to centrally position a threaded shank (144, 177; not shown) received therethrough such that the central axes of the threaded bore (114; not shown) and the threaded shank (144, 174; not shown) substantially co-align.

[00176] Further, the sidewall (202) of the adapter (200) is split defining three guide members (230) for collectively urging or biasing a threaded shank (144, 174; not shown) into a central alignment. The three guide members (230) extend at least partially inwards to the central conduit (210) at or near the inner end (204).

[00177] Each split extends in a linear orientation from the inner end (204) at least partially towards the outer end (206) in a direction parallel to a longitudinal axis of the adapter (200).

[00178] Advantageously, the splits in the adapter (200), apart from defining the guide members (230) for centrally positioning a threaded shank (144, 174; not shown), additionally facilitate in insertion of the adapter (200) into a threaded bore (114; not shown).

[00179] As shown, the outer end (206) of the adapter (200) includes a flange portion (240). The flange portion (240) extends radially outwards from the outer end (206) to an outer flange edge (242).

[00180] The flange portion (240) extends entirely about a periphery of the outer end (206) and is configured to at least partially abut against a sidewall (117; not shown) of the eyepiece block (110; not shown) or elevation block (152; not shown) when the adapter (200) is inserted into a threaded bore (114; not shown).

[00181] Referring briefly to Figure 2, a complementary recess (250) is defined about an outer opening of the threaded bore (114) for receiving the flange portion (240; shown in Figure 3) therein.

[00182] Referring to Figures 3 to 5, the adapter (200; shown in Figure 3) includes a retention mechanism for retaining the adapter (200; shown in Figure 3) in an axial position relative to the threaded bore (114; shown in Figure 4) by selectively preventing rotation of the adapter (200; shown in Figure 3) relative to the threaded bore (114; show in Figure 4).

[00183] The retention mechanism includes a retention fastener (510) shown in Figure 5 that is configured to be received through a groove (262) or opening (264) defined in the flange portion (240) of the adapter (200) as shown in Figure 3 and into a corresponding retention opening (410) defined in a sidewall (117) of the eyepiece block (110) or elevation block (152; not shown) shown in Figure 4.

[00184] Referring to Figure 3 in particular, the flange portion (240) includes a plurality of openings (264) and grooves (262) defined thereon in a spaced arrangement about the flange portion (240). The grooves (262) are defined in the outer flange edge (242).

[00185] Referring to Figure 5, the retention fastener (510) is threaded fastener with an enlarged head (520) having a socket for receiving a tool for applying torque to the fastener (510) and turning or rotating the retention fastener (510).

[00186] Referring to Figure 4, the corresponding retention opening (410) defined in the sidewall (117) of the eyepiece block (110) or elevation block (152; not shown) is located adjacent to and extends substantially parallel to the threaded bore (114) such that they share a common sidewall (420).

[00187] In use, an opening (264; shown in Figure 3) or groove (262; shown in Figure 3) and a corresponding retention opening (410) are co-aligned to receive the retention fastener (510; shown in Figure 5) therethrough for retaining the adapter (200) in place.

[00188] Insertion of the retention fastener (510; shown in Figure 5) into the retention opening (410) presses or urges the common sidewall (420) outwards and away from the retention opening (410) to applying a clamping or circumferential force on the adjacent threaded bore (114) to advantageously at least partially further assist in retaining the adapter (200; shown in Figure 2) in place.

[00189] A method (600) of using the adapter (200) as shown in Figure 2 for enhancing the accuracy of a rear sight (100) as shown in Figure 1 is now described in detail with reference to Figure 6.

[00190] At step 610, the rear sight (100) is disassembled to remove the eyepiece block (110) and/or elevation block (152) from its respective windage arm or elevation arm assembly (120, 150). The disassembly includes separating the eyepiece block (110) and/or elevation block (152) from the respective guide rails (130, 160) and adjustment screws (140, 170). [00191] At step 620, an adapter (200) is threadingly inserted into an inlet opening of the threaded bore (114) of the eyepiece block (110) and/or elevation block (152) such that the external thread (220) of the adapter (200) threadingly engages with the internal thread of the threaded bore (114).

[00192] The adapter (200) is threadingly inserted into the inlet opening of the threaded bore (114) until a desired axial position relative to the threaded bore (114) is achieved, typically until the flange portion (240) of the adapter (200) is in abutment with a sidewall (117) of the eyepiece block (110) and/or elevation block (152).

[00193] The retaining mechanism of the adapter (200) is then engaged to selectively prevent any further rotation of the adapter (200) relative to the threaded bore (114).

[00194] At step 630, the rear sight (100) is re-assembled by sliding the eyepiece block (110) and/or elevation block (152) over the respective guide rails (130, 160) prior to threadingly engaging the eyepiece block (110) and/or elevation block (152) with the threaded shank (144, 174) of the adjustment screw (140, 170) via the adapter (200).

[00195] A method (700) of altering a rotational direction of a windage or elevation adjustment screw (140, 170) of a rear sight (100) for a rifle (1000) as shown in Figure 1 is now described in detail with reference to Figure 7.

[00196] At step 710, the rear sight (100) is disassembled to remove the eyepiece block (110) and/or elevation block (152) from its respective windage arm or elevation arm assembly (120, 150). The disassembly includes separating the eyepiece block (110) and/or elevation block (152) from the respective guide rails (130, 160) and adjustment screws (140, 170).

[00197] At step 720, an adapter (200) is threadingly inserted into an opening opposite the inlet opening of the threaded bore (114) of the eyepiece block (110) and/or elevation block (152) from which the adjustment screws (140, 170) were removed at step 710.

[00198] The adapter (200) selected and threadingly inserted has the desired thread characteristics to at least partially complement the thread characteristics of the threaded bore (114) and a threaded shank (144, 174) of the adjustment screws (140, 170) received therethrough.

[00199] At step 730, the rear sight (100) is re-assembled by sliding the eyepiece block (110) and/or elevation block (152) in a reverse or inverted orientation compared to when it was disassembled at step 710. The eyepiece block (110) and/or elevation block (152) is slid over the respective guide rails (130, 160) prior to threadingly engaging the eyepiece block (110) and/or elevation block (152) with the threaded shank (144, 174) of the adjustment screw (140, 170) via the adapter (200).

[00200] A method (800) of altering a sight aperture (112) of a rear sight (100) for a rifle (1000) as shown in Figure 1 is now described in detail with reference to Figure 8.

[00201 ] At step 810, the rear sight (100) is disassembled to remove the eyepiece block (110) from the windage arm assembly (120). The disassembly includes separating the eyepiece block (110) from the guide rails (130) and the windage adjustment screw (140).

[00202] At step 820, an adapter (200) is threadingly inserted into an inlet opening of the threaded bore (114) of a replacement eyepiece block (110) having a sight aperture (112) of a desired radius.

[00203] The adapter (200) selected and threadingly inserted has the desired thread characteristics to at least partially complement the thread characteristics of the threaded bore (114) of the replacement eyepiece block (110) and a threaded shank (144) of the windage adjustment screw (140) received therethrough.

[00204] At step 830, the rear sight (100) is re-assembled by sliding the replacement eyepiece block (110) over the guide rails (130) prior to threadingly engaging the replacement eyepiece block (110) with the threaded shank (144) of the windage adjustment screw (140) via the adapter (200).

[00205] A method (900) of altering a thread direction, profile and/or ratio of a windage or elevation adjustment screw (140, 170) of a rear sight (100) of a rifle (1000) as shown in Figure 1 is now described in detail with reference to Figure 9.

[00206] At step 910, the rear sight (100) is disassembled to remove the eyepiece block (110) and/or elevation block (152) from its respective windage arm or elevation arm assembly (120, 150). The disassembly includes separating the eyepiece block (110) and/or elevation block (152) from the respective guide rails (130, 160) and adjustment screws (140, 170).

[00207] At step 920, an adapter (200) is threadingly inserted into an inlet opening of the threaded bore (114) of the eyepiece block (110) and/or elevation block (152).

[00208] The adapter (200) selected and threadingly inserted has the desired thread characteristics to at least partially complement the thread characteristics of the threaded bore (114) of the eyepiece block (110) and/or elevation block (152) and a threaded shank (144) of the replacement windage adjustment screw (140) and/or elevation adjustment screw (170) received therethrough.

[00209] At step 930, the rear sight (100) is re-assembled by sliding the eyepiece block (110) and/or elevation block (152) over the respective guide rails (130, 160) prior to threadingly engaging the eyepiece block (110) and/or elevation block (152) with the threaded shank (144, 174) of the replacement adjustment screw (140, 170) via the adapter (200).

[00210] In the present specification and claims (if any), the word ‘comprising’ and its derivatives including ‘comprises’ and ‘comprise’ include each of the stated integers but does not exclude the inclusion of one or more further integers.

[00211] Reference throughout this specification to ‘one embodiment’ or ‘an embodiment’ means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the present invention. Thus, the appearance of the phrases ‘in one embodiment’ or ‘in an embodiment’ in various places throughout this specification are not necessarily all referring to the same embodiment. Furthermore, the particular features, structures, or characteristics may be combined in any suitable manner in one or more combinations.

[00212] In compliance with the statute, the invention has been described in language more or less specific to structural or methodical features. It is to be understood that the invention is not limited to specific features shown or described since the means herein described comprises preferred forms of putting the invention into effect. The invention is, therefore, claimed in any of its forms or modifications within the proper scope of the appended claims (if any) appropriately interpreted by those skilled in the art.