US2253948A - Gun sight - Google Patents

Description

33-252. OR 292539948 5R 1941- L. H. BROWN 2,253,948

GUN SIGHT I Filed July 9, 1941 INVENTOR. 150 H BRow/v HTTORNEYS nmrcn nducer Patented Aug. 26, 1941 UNITED STATES PATENT OFFICE 1 Claim.

My invention relates to a new and improved gun sight, which is intended for use in connection with rifles, machine guns, etc.

One of the objects of the invention is to provide an adjustable sight whereby the marksman can regulate the elevation of the gun immediately, automatically and substantially correctly, in accordance with the trajectory of the ammunition which is being used.

Another object of my invention is to provide a gun sight which is turnable relative to a predetermined axis, in order to permit said regulation of the elevation of the gun, so that the adjusted sight can be used for firing at targets of different sizes, while using ammunition which has the same trajectory. This predetermined axis, around which the sight is turned or tilted, is preferably normal to the axis of the barrel. This predetermined axis is vertical, when the axis of the barrel is horizontal. The sight can also be adjusted for use on respective different guns, which use bullets or the lik which have respective different trajectories.

Other objects of this invention are stated in my application Serial No. 335,877, filed in the U. S. Patent Ofiice on May 18, 1940, and my application Serial No. 354,633, filed August 29, 1940, of which this application is a division in part and a continuation-in-part, reference being made to the disclosures of said applications with the same force and effect as if repeated herein.

Fig. 1 is a top plan view of an embodiment of my invention, on the line 2--2 of Fig. 2.

Fig. 2 is a front elevation of Fig. 1.

Fig. 3 diagrammatically illustrates a practical example in calculating the curves of the legs of the sight, as later stated herein.

Fig. 4 shows a reticule which can be used, if the invention is embodied in a telescopic sight.

The improved sight can be used as the front sight of a gun or rifle, in order to replace the conventional iron sight. In such case the rear sight should be a peep sight. The peep sight is well-known per s so that it is not illustrated in the drawing. The peep sight has a small opening, in order to show the front sight more clearly, while the eye of the marksman is focused on the target.

Figs. 1 and 2 show a gun barrel I, which has the bore 2. The barrel l is provided with a conventional dovetail slot, in which the corresponding supporting block 3 of the improved sight is located. The block 3 is held in said slot in any suitable manner. The improved sight is mounted in a frame 4, which is suitably connected to the block 3. The plane of this frame 4 is perpendicular to the longitudinal axis of the bore 2.

The sight 5 can be made of thin wire or of thin strip metal which is stamped out by a cutting die into the shape shown in detail in Fig. 3, so that the sight can be stamped out of a thin sheet of metal. Theoretically, and as shown in Fig. 3, the inner ends of the legs of the sight do not meet. In practice the distance between the inner or bottom ends of the legs is very slight, and said bottom ends meet in a shaft edge. The ends of the legs of the sight which are directly adjacent the barrel, are designated as the inner ends of the legs. These legs may also be designated as sight members.

While the invention is not limited to any particular type of ammunition or to any particular type of gun or the like, the following is given as a single illustrative example, in connection with Fig. 3.

It is assumed that the improved sight takes the place of the conventional front sight of a gun. This gun may be of any type, including a rifle, a machine gun or the like. This gun shoots a .30.30l grain cartridge. This example applies to several other types of cartridges which have approximately the same trajectory. This example, therefore, applies to the ordinary rifles which are used for hunting. It is also assumed that the target or object has a horizontal dimension of 1 foot and that the eye of the marksman will be held 2 /2 feet behind the front sight when said sight is non-telescopic. The distance be tween the eye of the marksman and the nontelescopic front sight may be varied within reasonable limits, without substantially lessening the accuracy of the device.

The gun is arbitrarily zeroed for the line A of Fig. 3 at a range of 50 yards. The line A corresponds to the substantially straight and horizontal outer or top-portions of the legs of the sight.

If this ammunition is used, the bullet has a drop of 2 inches at a range of yards, a drop of 6 inches at a range of yards, a drop of 14 inches at a range of 200 yards, a drop of 25 inches at a range of 250 yards, and a drop of 40 inches at a range of 300 yards.

The invention can also be applied to a telescopic sight, in which case the lines which correspond to the sight members 2 are etched or otherwise indicated upon a transparent reticule. Therefore, when I refer to a front sight in a claim, this includes a telescopic sight.

Fig. 4 shows the reticule of a telescopic sight,

in which the calibrating scale of the adjusting knob 8a. has its calibrations in units of target, this being the same type of scale which is illustrated in Fig. 1. Each horizontal line on this reticule represents the horizontal distance which covers a given width of the target, at the distance in yards which is indicated by the respective number which is etched in the reticule. For example, if the knob, 8 is set for a target whose known width is four feet, and said target is barely covered by the third line from the top of the reticule, this shows that the distance of the target is 150 yards.

As previously stated, the curved legs of the sight will theoretically never meet at their'inner ends, as shown in the scale representation of Fig. 3, which is drawn to a scale which is ten times the actual scale of the device. In Figs. 1 and 2, the parts are not drawn according to scale, as these figures are intended merely to illustrate the device generally. Likewise, in actual practice, a non-telescopic sight is free from the horizontal lines AF, which are shown in Fig. 3. These lines AF of Fig. 3 are used merely to explain the theory and operation of the improved sight, when the gun is aimed at an object whose horizontal dimension is 1 foot, and when using a bullet which has the previously-stated trajectory. In Fig. 3, the respective legs of the sight are designated by the reference letters L and La. The respective lengths of the lines AF betwen the lines L and La in a device which is made according to Fig. 3, using ammunition which has the aforesaid trajectory, for shooting at a. target which has a horizontal dimension of one foot, are as follows:

The respective vertical distances from the top line A to the other lines BF are as follows:

Inch

A to B 0.0167 A to C 0.0333 A to D 0.0583 A to E 0.0833 A to F 0.1111

In shooting at said object, the plane of the sight is held perpendicular to the axis of the barrel.

When the plane of the sight is perpendicular to the axis of the barrel, the lines AF respectively correspond to ranges of 50 yards, 100 yards, 150 yards, 200 yards, 250 yards, 300 yards, when shooting at the aforesaid target, with a bullet which has the aforesaid trajectory.

The marksman aims the gun at the aforesaid object, until its horizontal image has its ends coincident with the corresponding horizontal points of the legs of the sight. Under such conditions, if the horizontal image of said object is located on the horizontal line D, the range is 200 yards, and the gun has been automatically elevated to correspond to the aforesaid drop of 14.00 inches. The marksman need not calculate or estimate the range.

If the same ammunition is used, and the object has a horizontal dimension of 2 feet, for example, and the plane of the sight is normal to the axis of the bore 2, the marksman may locate the image of the object horizontally until one-half of the horizontal dimension of the image is located between the legs of the sight, one-quarter of the horizontal image is located at the left of the left-hand leg of the sight, and one-quarter of the horizontal dimension of the image is located to the right of the right-hand leg of the sight.

If the sight were dimensioned to shoot with the same ammunition at a target whose horizontal dimension was 2 feet, the length of line A, between its intersections with the legs of the sight, would be 0.400 inch, and the other horizontal dimensions would be doubled. The respective vertical distances between line A and lines BF would remain the same, since the trajectory of the bullet would remain the same.

The above directions apply where it is desired to hit the center of the target.

When the plane of the sight is perpendicular to the axis of the bore 2 of the rifle, said sight is designed for an object whose horizontal dimension is 1 foot. Strictly speaking, the sight is not in a single plane, but its legs or sight members are equivalent to two curved lines which are in the same plane.

The sight is turned around an axis which, for convenience, may be designated as a vertical axis, since said axis is vertical when the axisof the bore 2 is horizontal. By turning the sight around said vertical axis, the lengths of the projections on a plane which is perpendicular to the axis of the bore 2, of the portions of the parts of lines AF which are located between the legs of the sight, are diminished. For example, the sight may be turned around said vertical axis until the length of the projection of the intersecting part of the line D on said perpendicular plane is 0.040 inch, instead of being 0.050 inch. Therefore, if the object or target has a horizontal dimension of 0.80 foot instead of having a horizontal dimension of 1 foot, and the range is 200 yards, the ends of the horizontal image of said object (having a horizontal dimension of 0.80 foot) will then coincide with the points of intersection between the line D and the legs of the target. Therefore, the respective devices can be used by adjusting the sight, in order to correspond to objects whose horizontal dimensions are smaller than the horizontal dimension of the object for which the sight is designed, when the plane of said sight is perpendicular to the axis of the bore 2.

For example, when the plane of the sight is perpendicular to the axis of the bore 2, the sight may be shaped and dimensioned so as to correspond to an object whose horizontal dimension is 0.80 foot. By turning the head 80. of the sight, it can be adjusted so as to correspond to objects having respective horizontal dimensions of 0.70 foot, 0.60 foot, etc. The scale in Figs. 1 and 2 is located on the turnable adjusting head 8a of the sight, and the index 8 is located on the frame 4.

In addition to adjusting the sight on a rifle or gun whose ammunition has a predetermined trajectory, for targets which have different horizontal dimensions, the improved adjustable sight can be adjusted for use on different guns or rifles whose ammunition has difierent respective trajectories, for shooting at a target of the same horizontal dimension.

For example, assume that it is desired to fire at a target whose horizontal dimension is one OO- ULUWIL I HLIHL INQIHUWILNIQQ earth Rood foot, with ammunition whose trajectory is flatter than the trajectory previously mentioned.

At a range of 200 yards, for example, the elevation of the gun or rifle must then be decreased, in order to compensate for said flatter trajectory, since the drop is less than in the example previously given. The sight is then turned around its vertical axis, in order to correspond to said flattened trajectory.

Both embodiments are based upon the same essential principle. Each embodiment may be considered in connection with a reference plane which is perpendicular to the axis of the barrel. This reference plane may be considered as having a number of predetermined reference lines which are parallel 'to each other and which are perpendicular to respective lines which are parallel to the axis of the barrel. These reference lines are the imaginary lines A-F in Fig. 3 and the etched lines of Fig. 4. These reference lines are taken at predetermined distances from the axis of the barrel, along a line which is perpendicular to the axis of the barrel, and in said reference plane. The respective distances between the sight members, measured along said respective reference lines, correspond to the respective correct elevations for a series of ranges of a target.

The horizontal dimension of the target may be designated as a guide dimension. Any guide dimension other than the horizontal dimension may be used.

The sight members are inclined to each other in fixed relation, when the sight is being used.

If the ends of the horizontal lines in Fig. 4 are joined by respective curved lines, said curved lines will correspond to the lines L and La of Fig. 3. Henc Fig. 3 and Fig. 4 are based on the same principle. The tips of the horizontal lines of Fig. 4 therefore define the same sight members which are shown in Fig. 3, and Figs. 3 and 4 are optical equivalents, and I include the horizontal lines of Fig. 4, whenever I specify the sight members of Fig. 3 in a claim.

I have shown preferred embodiments of my invention, but it is clear that numerous changes and omissions can be made without departing from its spirit.

I claim:

For use on the barrel of a rifle or the like, a front sight which has inwardly extending sight members which are inclined towards each other in fixed relation, the horizontal distances between said sight members being spaced from the bore of the barrel in amounts corresponding to the respective correct elevations for a series of ranges of a target which has a predetermined guide dimension adapted to be optically spanned by one distance between said members as the rifle is aimed, a support adapted to mount said sight on said barrel, said sight being turnable relative to said support around an axis of tilting which is substantially perpendicular to the axis of the bore, said axis of tilting being substantially vertical when the axis of the bore is horizontal.

LEO H. BROWN.

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