Firearms – Implements – Sight devices
Reexamination Certificate
2002-03-19
2003-07-15
Carone, Michael J. (Department: 3641)
Firearms
Implements
Sight devices
C042S130000, C073S167000
Reexamination Certificate
active
06591537
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to telescopic rifle sights. More particularly, the invention relates to a telescopic gunsight equipped with a transparent aiming reticle and a method for using that reticle.
2. Description of the Prior Art
It is well known that the line of sight between a rifle shooter's eye and a target is a straight line, whether using “iron” sights or a telescopic sight, while the trajectory of the rifle bullet is never a straight line (when passing though a gravitational field, the trajectory follows a ballistic parabola), particularly for bullet flights over long distances. Accordingly, in order to achieve accurate shot placement, it is essential either to “sight in” the rifle for the target distance or to know both the distance from the rifle to the target and the trajectory characteristics of the bullet used. Trajectory characteristics for commercial bullets are known and are easily obtained from either the manufacturer or from trajectory charts such as the INGALLS' tables.
Telescopic gunsights, often referred to as “scopes,” generally contain a transparent flat disk reticle positioned in a plane perpendicular to the line of sight through the scope. The reticle conventionally has a single vertical crosshair (or hairline) and a single horizontal crosshair (or hairline), which intersects the vertical hairline near the visual center of the reticle. The point of intersection of these crosshairs constitutes the primary sighting point for the scope, representing the site of bullet impact at a chosen (zero) distance. The gunsight is moveable in vertical and horizontal directions by way of calibrated adjustment screws on the exterior of the scope (internal adjustments), or on the scope attachment system (external adjustments).
By firing a series of shots while making compensatory adjustments of the relative position of the gunsight and thus of the reticle center point, the shooting system comprised of rifle, bullet type, scope and shooter are “zeroed in” so that the position on the target of the crossed hairlines or center point of the reticle coincides with the point of bullet impact.
In certain scope sighting systems the reticle has a series of evenly spaced secondary horizontal hairlines that intersect the vertical hairline below the center horizontal hairline. In those systems, the respective points of intersection of the secondary hairlines with the vertical hairline are typically used to estimate bullet impact points at distances progressively greater than that at which the rifle was “zeroed in” with the main (center) horizontal crosshair. However, in order to utilize the secondary crosshairs with accurate results, the shooter must know with some precision the distance from gun to target.
Various types of range finder systems have been disclosed for telescopic gunsights. For example, U.S. Pat. No. 1,190,121 to Critchett discloses a reticle having a series of target-spanning rulings disposed above a baseline, the rulings corresponding to associated shooting distances. In use, the shooter ascertains which ruling above the baseline makes the most closely embracing fit on the target, thereby determining the shooting distance (target range). A separate crosshair aiming point is included in the reticle for use in association with each chosen ruling above the baseline.
The principle of the Critchett target-spanning rulings is that certain targets are of known, or at least estimable size. For instance, it is a fairly accurate estimate that for mature deer or antelope, the distance between the top of the back at the shoulders and the bottom of the chest cavity is about 18 inches. The target-spanning rulings are spaced apart such as to span a known target size at a known range. This manner of distance measurement is consistent with conventional trigonometric considerations wherein the triangle defined by the height of the target and the viewing angle through the telescope's optical system can be considered a right triangle, which accordingly establishes the length of the base line distance to the distal side of the triangle, namely the distance to the target.
U.S. Pat. No. 3,392,450 to Herter et. al. discloses a reticle having a series of target-spanning circles of different diameters which correspond to associated shooting distances. Employing the same basic distance-measuring concept as Critchett, the shooter employs for aiming purposes, that crosshair which corresponds to the selected circle.
U.S. Pat. No. 3,190,003 to O'Brien concerns a range-finding reticle for a telescopic gunsight having single centered vertical and horizontal hairlines. The portion of the vertical hairline below the horizontal centerline is provided with widened bar regions extending various lengths below the centerline. Each bar subtends a target of known size. By finding which widened region corresponds to the height of the target, the shooting distance is estimated.
U.S. Pat. No. 3,431,652 to Leatherwood discloses a telescopic gunsight wherein the distance to the target is determined by movement of upper and lower horizontal hairlines along a fixed vertical hairline in a manner so as to bracket the target. Once bracketed, the intersection of the lower horizontal hairline with the vertical hairline serves as the crosshair aiming point. In this aiming process, the alignment of the scope changes with respect to the gun barrel, whereby the allowance for distance is achieved when the centered crosshair is sighted directly on the target.
U.S. Pat. No. 3,492,733 to Leatherwood discloses a distance measuring system for a variable power telescopic sight that is pivotally moveable in a vertical plane with respect to the gun barrel upon which it is mounted. Cams within the scope and rotatable by external means achieve vertical movement of the scope so that horizontal framing hairlines will fit the target. A specialized cam must be installed into the scope for each particular type of ammunition employed.
U.S. Pat. No. 3,948,587 to Rubbert concerns a variable power telescopic sight having a reticle provided with a vertical hairline, a center horizontal hairline and three horizontal framing lines disposed below the center horizontal hairline. Aiming is achieved by positioning either the center crosshair or lower crosshairs on the target, as dictated by the observed fit of the target within the framing lines.
U.S. Pat. No. 4,403,421 to Shepherd discloses a telescopic gunsight having spaced apart primary and secondary reticles which are moveable relative to each other. The secondary reticle is also moveable vertically and horizontally within the plane of the reticle. The moveable two reticle system facilitates adjustments for windage and elevation. Distance to the target is ascertained by framing indicia on the secondary reticle.
The telescopic sights disclosed in the aforementioned prior art patents are often of limited usefulness insofar as they do not address many of the several factors that need to be considered in the accurate aiming of a rifle under field conditions. Such factors include:
a) distance to target
b) drop of bullet caused by force of gravity
c) hold-over or hold under points
d) wind drift correction
e) correction for phenomenon associated with gyroscopic forces on a gyroscopically stabilized bullet (sometimes referred to as)
1) Yaw of Repose effects (vertical displacements)
2) Magnus effects (horizontal displacements)
These latter result from the effect of cross-wind or shooting either up-hill or down-hill.
Older reticle systems often require that the shooter look away from the target in order to make compensating adjustments. Some of these designs may render the scopes difficult or slow to use, and some require moveable mounting on the rifle, a situation which subjects the scope to inaccuracy after repeated use or abuse in rugged field conditions. Moreover, correct use of any of these systems requires the shooter to manage extraordinary mental work.
SUMMARY OF THE INVENTION
The present invention is embodied in a reticle
Buckley Denise
Carone Michael J.
LandOfFree
Reticle for telescopic gunsight and method for using does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Reticle for telescopic gunsight and method for using, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Reticle for telescopic gunsight and method for using will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3109967