Firearms – Implements – Sight devices
Reexamination Certificate
2003-01-21
2004-05-04
Carone, Michael J. (Department: 3641)
Firearms
Implements
Sight devices
C042S123000, C042S130000, C042S131000
Reexamination Certificate
active
06729062
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention generally relates to a mil-dot reticle. In particular, the invention relates to a targeting reticle for firearms and the like, whereby a plurality of dots are and evenly-spaced hash-mark graduations between the dots are combined to form the reticle
2. Description of the Related Art
A reticle is a grid or pattern placed in either of two focal planes of an optical instrument, such as a riflescope to establish scale or position. As shown in
FIG. 1
, the first focal plane A is between the objective lens assembly
1
and the erector lenses
6
, a location where the first image from the objective
1
is projected. This image is up side down. The objective lens assembly
1
includes, typically, two or three larger lenses forming the objective lens assembly and is mounted in the objective end
2
of the optic. It is called an objective lens because it is closest to the “object” being viewed. The erector lenses
6
turn/rotate the image in the first focal plane A 180 degrees, i.e., erecting the image. The second focal plane B is between the erector lenses
6
and the ocular assembly
7
. After light rays pass through the erector lenses
6
, the image is projected onto this location, where the image will be seen by the user when looking in the scope from the right end
8
. The reticles in the first focal plane A are sometimes referred to as magnifying reticles because appearance changes at the same ratio as the image size. Any reticle with markers off center and installed in the first focal plane A will have the same subtension (coverage on the target, i.e., spacing and size) regardless of the power setting in a variable power scope. The user can range estimate at any power and compensate for moving target leads to suit conditions. For example decreasing power allows a larger field of view and more light transmission.
Any reticle in the second focal plane B is often referred to as a non-magnifying reticle because the appearance to the eye is the same to the eye regardless of power setting in a variable power scope. Any reticle having markers off the center of the reticle will have correct spacing at only one magnification. The scope tube or housing
3
is designed to hold the various component parts. The top adjustment
5
moves the reticle so as to zero the scope can be zeroed. A second adjustment (not shown) may be place on the side of the tube at 90 degrees to the top adjustment
5
.
Even though riflescopes have become increasingly sophisticated, the basic constriction has remained the same. Light rays entering the objective lens are magnified. The resulting enlarged and upside-down image proceeds through the erector lens system, which magnifies and corrects the image to the right-side-up position. Finally, the ocular lens further magnifies and projects the target image and reticle to the user's eye.
The reticle is positioned within the optical system to coincide with the plane of focus of the objective lens or lens group. In a variable power scope, as the spacing between the lenses changes, the magnification of the scope also changes. The total travel of the lenses is called the zoom ratio. Typically it would be a 3× ratio. Variable power scopes have powers specified in these ratios. For example 3.5×-10× or 2.5×-8×. Ratio is up to the manufacturer and may be anywhere between 3× and 5×.
The reticle is commonly referred to as the “crosshair,” and often consists of fine wires, dots, pointed posts or other distinct shapes that appear superimposed on the first or second focal plane. In principle, relatively bold reticles aid rapid aiming, while finer reticles subtend less of the target and may be less prominent, but are conducive to precise shot placement when aiming carefully and deliberately.
U.S. Pat. No. 6,032,374 shows a telescopic gunsight with a reticle having a primary vertical line
20
, a primary horizontal line
22
intersecting the primary vertical line
20
, a plurality of secondary horizontal lines
24
each having a predetermined thickness and evenly spaced a predetermined distance along the primary vertical line
20
, a plurality of secondary vertical lines
26
each having a predetermined thickness and evenly spaced a predetermined distance along at least some of the secondary horizontal lines
24
, and a range-finder
30
positioned in one of the quadrants formed by the intersection of the primary vertical and horizontal lines. A plurality of half hash-marks (2.5 inches of angle) are placed between the secondary horizontal lines
24
. The horizontal lines are asymmetrical to the optical center
21
with fewer and shorter lines on the top. The vertical lines mirror to the primary vertical line
20
with numbers
28
. The range-finder
30
is placed at the lower left quadrant. The asymmetrical arrangement in conjunction with the numerous hairs complicate the reticle and can confuse the user. A plurality of horizontal half hash-marks further distract the user. In addition, the spacing between the lines is most preferably based upon the “inches of angle” scale rather than the “minute of angle” scale or Mil Radian scale, which have been adopted by the military for years.
Radians are used in a coordinate system called “polar coordinates.” The radian is a unitless measure which is equivalent, in use, to degrees. It is an angular measure equal to the angle subtended at the center of a circle by an arc equal in length to the radius of the circle, approximately 57° 17′44.6″0.2&pgr; radians=360 degrees. A point on the plane is defined, in the polar coordinate system, using the radian and the radius. The radian defines the amount of rotation and the radius gives the distance from the origin (in a negative or positive direction).
Switching from the “degree” mode to the “radian” mode, one milliradian={fraction (1/1000)} (0.001) radians in the mil-dot reticle. The mil-dot reticle, which was designed to help U.S. Marine Corps snipers estimate distances, became standard for all military branches. All mil-dot reticles in current use have 10 mils space vertical and horizontal. The mil-dot reticle does not limit the user to one size or a limited number of sizes. The mil-dot reticle is now also the standard reticle found in law enforcement riflescopes. It has been adopted over the years by sportsman and hunters as a serious aid for range estimating. The mil-dot reticle is a reliable means for determining distances to targets, establishing leads for moving targets, and for alternating aiming points for windage and elevation considerations. Military snipers who have been trained in formal instruction programs spend numerous hours honing their ability to use the mil-dot reticle so as to be comfortable and competent with it. In contrast, some civilian tactical and practical long-range precision shooters are hesitant of the mil-dot reticle because of a lack of proper training. Aids available for the proper use of the mil-dot reticle include a simple formula that can be used with a calculator, mil tables or a slide rule type calculator called the MILDOT MASTER™. This calculator can be found at this link http://www.premierreticles.com/mildotmstr.htm.
The mil-dot reticle is designed around the measurement unit of the milliradian. The dots and the spacing of the dots are also designed based upon the milliradian. The space between dot centers subtends one milliradian(mil). This allows a shooter to calculate the distance to a target of a known height or width. For example, the height of the target in yards divided by the height of the target in milliradians multiplied by 1000 equals the distance to the target in yards. The height or width of the target has to be known to use this system effectively. A milliradian is an angular unit of measure that equals one yard at 1000 yards and 1 meter at 1000 meters. The distance to a target can be decided when the size of the target is known. The shooter simply measures the target using the dots, then uses a simple formula
Thomas Chris
Thomas Richard L.
A. Marquez, Esq. Juan Carlos
Buckley Denise J
Carone Michael J.
Fisher Esq. Stanley P.
Reed Smith LLP
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