US20120297659A1

US20120297659A1 - Pendulum crosshair for weapon sight

Info

Publication number: US20120297659A1
Application number: US13/451,203
Authority: US
Inventors: Carl L. Lattimer
Original assignee: Individual
Current assignee: Individual
Priority date: 2011-05-25
Filing date: 2012-04-19
Publication date: 2012-11-29

Abstract

The pendulum crosshair for a weapon sight incorporates a thin, rigid wire pivotally suspended at its upper end to a point at or immediately above the peripheral end point of the fixed vertical crosshair in the reticle of a weapon sight. If the weapon, and thus the sight, is tilted or canted from the vertical when aiming, the pendulum crosshair will misalign with the fixed vertical crosshair in the sight to indicate to the shooter that the weapon is canted. This allows the shooter to correct the cant or tilt of the weapon to avoid the lateral displacement of the shot that would otherwise occur due to lateral displacement of the elevation correction for the sight line.

Description

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit of U.S. Provisional Patent Application Ser. No. 61/489,905, filed May 25, 2011.

BACKGROUND OF THE INVENTION

1. Field of the Invention
The present invention relates generally to sighting devices for firearms and archery bows, and particularly to a pendulum crosshair for a weapon sight to alert the marksman of an out of plumb orientation of the weapon.
2. Description of the Related Art
Virtually all weapons intended for serious hunting and/or target use include sights that are adjustable for elevation, i.e., to compensate for the drop or fall of the projectile (bullet, arrow, etc.) between the time it is fired and the time it reaches the target. As an example of the above, a bullet or round traveling at an average velocity of 2,000 feet per second to a target that is 2,000 feet away from the shooter will be accelerated downward by the force of gravity at a rate of about 32 feet per second per second, for a drop or fall of about sixteen feet over the 2,000 foot distance. Of course, arrows travel at a considerably slower speed and over shorter distances, but the principle remains the same. Accordingly, weapon sights universally have some means to compensate for this factor by angling the sight slightly downward so that the weapon is aimed slightly high when the sight is precisely on the target. Ideally, the line of sight of the scope or other sights and the parabolic arc traveled by the projectile will meet at the range of the target, or very close to that range. At relatively longer ranges, the bullet will actually tend to rise somewhat above the line of sight of the scope before dropping back below the sight line as its energy is expended.
A problem with the above is that such an elevation correction will only be absolutely accurate when the weapon is aligned vertically relative to gravity, i.e., the weapon is held in a plumb orientation. If the weapon is canted or tilted relative to the vertical, the elevation correction will be canted from the vertical accordingly. The lateral error induced will depend upon the angle of the cant of the weapon, as well as the angle subtended between the sight line and the alignment of the projectile when it is fired from the weapon (i.e., the bore of the firearm or the alignment of the arrow when released) and, of course, the distance to the target. All other things being equal, the greater the cant or tilt angle of the weapon from the vertical, the greater will be the resulting lateral error between the sight line to the target and the impact point of the projectile at the target distance.
Thus a pendulum crosshair for a weapon sight solving the aforementioned problems is desired.

SUMMARY OF THE INVENTION

The pendulum crosshair for a weapon sight comprises a sight reticle having a pivotally movable crosshair therein, formed of a thin, rigid wire or the like. The pivoting crosshair is suspended at its upper end at or immediately above the peripheral end point for the upper end of the fixed vertical crosshair in the reticle, the pivoting crosshair being free to pivot about its attachment point. The movable pivoting crosshair acts as a pendulum, always hanging vertically within the reticle, regardless of the lateral tilt or cant of the reticle. The shooter need only orient the weapon so that the pivotally attached crosshair is directly aligned with the fixed vertical crosshair of the sight reticle to assure that the weapon is being held vertically or plumb with no lateral tilt or cant. This assures the shooter that the elevation correction is entirely in the vertical plane, and will not throw off the aim laterally due to an undesired lateral component as a result of the cant or tilt of the weapon. The device may be applied at the focal plane of a telescopic sight for a firearm, e.g., a rifle, or may be applied to the sighting mechanism of an archery bow sight or other weapon sighting system.
These and other features of the present invention will become readily apparent upon further review of the following specification and drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a diagrammatic view of a rifle with telescopic sight having a pendulum crosshair and sight reticle, shown enlarged separately, showing the general path of a bullet fired from the rifle when the rifle is canted, i.e., not plumb.

FIG. 1B is a diagrammatic view of a rifle with telescopic sight having a pendulum crosshair and sight reticle, shown enlarged separately, showing the general path of a bullet fired from the rifle when the rifle is plumb.

FIG. 2 is an exploded environmental perspective view of a firearm scope and reticle incorporating a pendulum crosshair for a weapon sight according to the present invention, showing installation of the crosshair in the second or rear focal plane of the scope, the scope being shown in broken lines.

FIG. 3 is an exploded detailed rear perspective view of a pendulum crosshair for a weapon sight according to the present invention, showing installation of the pendulum crosshair in the reticle.

FIG. 4A is a rear elevation view of an archery how sight having a pendulum crosshair for a weapon sight according to the present invention, showing the alignment of the crosshair with the vertical crosshair of the reticle to indicate that the weapon is plumb.

FIG. 4B is a rear elevation view of the archery bow sight of FIG. 4A, showing misalignment of the crosshair with the vertical crosshair of the reticle to indicate that the weapon is not plumb.

Similar reference characters denote corresponding features consistently throughout the attached drawings.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The pendulum crosshair for a weapon sight provides the shooter with information regarding the vertical alignment of his or her weapon, thereby allowing the shooter to maintain true vertical alignment of the weapon and corresponding elevation adjustment between the sight system and the initial projectile path as defined by the firearm bore or arrow release. This is desirable in order to prevent the introduction of a lateral component to the plane defined by the sight line of the weapon sights and the parabolic path of the projectile after it has been fired. If the weapon is tilted or canted from the vertical, i.e., out of plumb, the resulting lateral offset of the sight line and projectile path will result in lateral displacement of the impact point of the projectile on the target, even when the sight line is aligned precisely with the center of the target. The pendulum crosshair is adaptable to any practicable weapon sight, including telescopic sights for firearms (rifles, etc.) and archery bow sights.
FIGS. 1A and 1B illustrate the vertical or plumb alignment of a firearm F1 and the vertically tilted or out of plumb alignment of a firearm F2, respectively. In the case of FIG. 1A the firearm F1 is plumb or vertically oriented, as noted. This places the plane defined by the sight line L1 of the sight S1 (e.g., telescopic sight, as shown in FIGS. 1A and 1B) and the vertical parabolic path P1 of the bullet or projectile in flight in the vertical, i.e., with no lateral offset. Thus, the flight path of the bullet or projectile remains coplanar with the plane of the sight line L1 and the projectile path P1, so that the projectile strikes the target T1 in vertical alignment with the point of intersection of the sight line L1 with the target T1. If the elevation correction has been set properly and all other factors (e.g., windage, etc.) properly accounted for, the projectile will strike the target T1 at precisely the point of intersection of the sight line L1 with the target T1 with no lateral or vertical error. The vertical alignment of the firearm F1 is clearly indicated by the weapon sight 10, which has a pendulum crosshair 12 aligned vertically with the vertical crosshair 14 of the reticle of the sight 10.
FIG. 1B provides an illustration of the error introduced when the firearm is tilted out of the vertical, or out of plumb. In FIG. 1B, the firearm F2 is tilted to the right, out of plumb with the vertical. The sight line L2 of the sight S2 is still aligned with the aiming point of the target T2, just as in the case of FIG. 1A. However, the lateral tilt of the firearm F2 has resulted in a corresponding lateral tilt of the plane defined by the sight line L2 and the parabolic path of the projectile P2. This lateral tilt results in a horizontal offset of the impact point of the projectile with the target T2, as shown in FIG. 1B of the drawings. The lateral tilt or out of plumb orientation of the firearm F2 is clearly indicated by the tilted weapon sight 10 in FIG. 1B, the vertical crosshair 14 being tilted at an angle from the vertical corresponding to the tilt or cant of the firearm F2, the pendulum crosshair 12 remaining in the vertical to show the angular difference between the vertical crosshair 14 and pendulum crosshair 12.
FIG. 2 is an illustration of an exemplary installation of the weapon sight 10 with a telescopic sight S, with the sight S being shown in broken lines, The weapon sight 10 comprises a periphery or frame 16 surrounding a sight reticle 18, the reticle 18 including the fixed vertical crosshair 14 described further above and a fixed horizontal crosshair 20, which may be etched onto a lens, or onto a thin, transparent plastic disc, or onto any other crosshair support (a sight reticle support) known in the art, or which may be formed by fibers embedded into a lens, plastic disk, or other sight reticle support, or which may be formed on a sight reticle support in any other manner known in the art. The two fixed crosshairs 14 and 20 extend diametrically across the reticle 18 and periphery 16. Each crosshair 14 and 20 has opposite ends terminating at the periphery 16 of the sight 10, e.g., the upper end 22 of the vertical crosshair 14 terminating at the uppermost point of the periphery 16 of the sight 10. The movable pendulum crosshair 12 is aligned with the fixed vertical crosshair 14 of the weapon sight 10 shown in FIG. 2, and is thus not visible separately. The weapon sight 10 may be installed at the rearward or second focal plane of the telescopic sight S by removing the eyepiece E of the sight and reinstalling the eyepiece E when the sight 10 has been installed, generally as shown in FIG. 2. Alternatively, the weapon sight 10 may be installed farther forward in the telescopic sight S in the forward or first focal plane (not shown), if desired.
FIG. 3 of the drawings provides a detailed exploded perspective view of the weapon sight 10, illustrating the installation of the pendulum crosshair 12 therewith. A small pin passage 24 is formed at the top of the frame or periphery 16 of the sight, adjacent the upper end 22 of the fixed vertical crosshair 14 and in vertical and axial alignment therewith. The pendulum crosshair 12 has a small eye 26 at its upper end. A pendulum crosshair attachment pin 28 is installed through the eye 26 of the pendulum crosshair 12, the pin having a head with a diameter larger than the diameter of the eye 26. A small spacer or washer 30 is placed over the shaft of the pin 28 after the shaft of the pin is passed through the eye 26 of the pendulum crosshair 12, before installing the pin 28 in the passage 24 of the sight periphery 16.
The movable pendulum crosshair 12 is of very lightweight, preferably being formed of a very thin strand of metal wire or other suitable material. The pendulum crosshair 12 preferably has a length 32 of only about half the vertical span of the sight reticle 18 as subtended by the fixed vertical crosshair 14, i.e., the pendulum crosshair 12 extends from its attachment pin 28 only to the center of the reticle 18, as defined by the intersection of the fixed vertical and horizontal crosshairs 14 and 20 and as shown in FIG. 1B of the drawings. The spacer or washer 30 precludes binding of the movable pendulum crosshair 12 on the periphery or frame 16 and/or the reticle 18 of the sight 10, thus permitting smooth arcuate motion of the pivotally suspended, lightweight pendulum crosshair 12 as the sight 10 is tilted or canted laterally.
FIGS. 4A and 4B of the drawings show the incorporation of a weapon sight having a pendulum crosshair, the sight being vertically oriented in FIG. 4A, and having a cant or tilt in FIG. 4B. FIGS. 4A and 4B are thus somewhat analogous to FIGS. 1A and 1B, but the weapon sight of FIGS. 4A and 4B is adapted for use with an archery bow rather than a firearm. Accordingly, the archery sight of FIGS. 4A and 4B is designated as weapon sight 110, and extends from an archery bow attachment bracket B1 (FIG. 4A) and B2 (FIG. 4B). The only difference between the brackets B1 and B2 is their orientation relative to the vertical.
The two archery bow sights 110 of FIGS. 4A and 4B are configured identically to the weapon sights 10 of FIGS. 1A through 3, with the exception of their attachment means. Each of the archery bow sights 110 has a pivotally moving pendulum crosshair 12 aligned with the fixed vertical crosshair 14 of the sight 110 when the sight is oriented vertically, the pendulum crosshair 12 being pivotally attached to the upper center of the peripheral frame 16 of the sight, substantially as shown in FIG. 3 for the sight 10 and described further above. A fixed horizontal crosshair 20 extends diametrically across the periphery 16, the vertical and horizontal crosshairs 14 and 20 forming the sight reticle 18.
In the case of FIG. 4A the archery bow is plumb or vertically oriented, as evidenced by the orientation of its sight mounting bracket B1. This places the plane of the arrow or projectile path and the elevation sight line in the vertical, or parallel to the sight plane referenced by the vertical crosshair 14 of the sight 110, with no lateral offset. Thus, the flight path of the arrow or projectile remains coplanar with the plane of the sight line and the arcuate projectile path, similar in principle to the scenario described further above, as shown with the firearm in FIG. 1A.
FIG. 4B provides an illustration of the error introduced when the archery bow is tilted out of the vertical, or out of plumb. In FIG. 4B, the archery bow is tilted or canted to the left, out of plumb with the vertical, as evidenced by the orientation of the sight mounting bracket B2. The lateral tilt or out-of-plumb orientation of the archery bow and its sight bracket B2 is clearly indicated by the tilted weapon sight 110 in FIG. 4B, the vertical crosshair 14 being tilted at an angle from the vertical corresponding to the tilt or cant of the bow and sight bracket B2, and the pendulum crosshair 12 remaining in the vertical to show the angular difference between the vertical crosshair 14 and pendulum crosshair 12.
It is to be understood that the present invention is not limited to the embodiments described above, but encompasses any and all embodiments within the scope of the following claims.

Claims

1. A pendulum crosshair for a weapon sight, comprising:

a sight reticle support defining a periphery;

a fixed vertical crosshair disposed diametrically across the sight reticle support, the fixed vertical crosshair having an upper end adjacent the periphery of the sight reticle support;

a pendulum crosshair mount disposed at the periphery of the sight reticle support adjacent the upper end of the fixed vertical crosshair; and

a movable crosshair pivotally suspended from the crosshair mount.

2. The pendulum crosshair for a weapon sight according to claim 1, further comprising a weapon sight, the sight reticle support being mounted in the weapon sight.

3. The pendulum crosshair for a weapon sight according to claim 2, wherein the weapon sight is a firearm telescopic sight.

4. The pendulum crosshair for a weapon sight according to claim 2, wherein the weapon sight is an archery bowsight.

5. The pendulum crosshair for a weapon sight according to claim 1, wherein the sight reticle support has a vertical span, the movable crosshair having a length substantially one-half the vertical span of the sight reticle support.

6. The pendulum crosshair for a weapon sight according to claim 1, wherein the pendulum crosshair attachment is a pin, the pendulum crosshair being suspended from the pin, the pendulum crosshair further comprising a spacer disposed on the pin between the pendulum crosshair and the periphery of the sight reticle support.

7. The pendulum crosshair for a weapon sight according to claim 1, wherein the pendulum crosshair is a thin metal wire.

8. A sight, comprising a weapon sight having a pendulum crosshair assembly, the assembly having:

a sight reticle support mounted in the weapon sight, the sight reticle support defining a periphery;

a pendulum crosshair pivot disposed adjacent the upper end of the fixed vertical crosshair and axially aligned therewith; and

a movable crosshair pivotally suspended from the crosshair pivot.

9. The sight according to claim 8, wherein the weapon sight is a firearm telescopic sight.

10. The sight according to claim 8, wherein the weapon sight is an archery bowsight.

11. The sight according to claim 8, wherein the sight reticle support has a vertical span, the movable crosshair having a length substantially one half the vertical span of the sight reticle support.

12. The sight according to claim 8, wherein the pendulum crosshair attachment is a pin, the pendulum crosshair being suspended from the pin, the sight further comprising a spacer disposed on the pin between the pendulum crosshair and the periphery of the sight reticle support.

13. The sight according to claim 8, wherein the pendulum crosshair is a thin metal wire.