US3184851A

US3184851A - Gun sight

Info

Publication number: US3184851A
Application number: US250529A
Authority: US
Inventors: Ernest P Simmons
Original assignee: Individual
Current assignee: Individual
Priority date: 1963-01-10
Filing date: 1963-01-10
Publication date: 1965-05-25
Anticipated expiration: 1982-05-25

Description

United States Patent 3,184,851 GUN SIGHT Ernest P. Simmons, 2510 Lafayette, Kansas City, Kans. Filed Jan. 10, 1963, Ser. No. 250,529 3 Claims. (Cl. 33-47) This invention relates to new and useful improvements in gun sights, and has particular reference to a sight of the class commonly know as glowgsights such as used as the front sights of shotguns. N

In glow sights, there is commonly provided a small cylindrical plug of transparent or translucent material mounted at the forward end of a shotgun barrel, its axis being generally parallel to the barrel axis so that the gunner sees only the rearward end thereof when sighting the gun. Light entering the plug along the exposed sides thereof is trapped therein due to the fact that the plug is formed of .a material, such as lucite or certain other plastics, having an unusually high light refraction index. That is, an unusually high proportion of the light entering the plug does not immediately emerge therefrom, but is reflected from the internal surfaces thereof, and tends to travel longitudinally along the plug, internally thereof, until it reaches the end of the plug and strikes the internal surface thereof at an angle still greater than the refractive index thereof, whereupon it emerges from the plug. This elfect of confining or piping of light is well known, and is effective even to confine the light in a curved plug, so as to pipe the light around a corner, so long as the radius of curvature is not too small. The effect is often used in medical instruments to illuminate areas of difiicult access. In gun sights as described, the effect provides that the end of the plug will glow brightly and thus facilitate the sighting operation. The brightness is further enhanced if the material of which the plug is formed is impregnated with luminescent dyes or the like.

An important object of the present invention is the provision, in a gun sight of the character described, of a special shape for the plug which further enhances the brightness thereof, so that it will glow brightly even on very dull and cloudy days. Generally, this special shape is provided by 'gl-o'dving the cylindrical side wall of the plug so as to provide a large area thereof more nearly normal to the axis of the plug, so that more light will enter the plug at a small enough angle to said axis to be retained in the plug by internal reflection as described above.

Another object is the provision of a special mounting for the plug whereby said plug, or more particularly the bead of bright light ailorded thereby, appears to rest directly on the gun barrel, rather than being spaced thereabove. In previous sights of this general type, to my knowledge, the necessity of a mounting piece for the plug caused the plug to be elevated from the gun barrel, which rendered the line of sight inaccurate as being angled upwardly from the axis of the barrel. In many guns, particularly guns wherein the front sight must be installed on the upper surface of a ventilated sighting rib extending the length of the barrel, the resultant inaccuracy necessitated realignment of the barrel. This realignment amounted to curving or bending the forward portion of the barrel upwardly so that the shot would be discharged parallel to the line of sight.

Other objects are simplicity and economy of construction, efliciency and dependability of operation, and adaptability for use on many different types and styles of guns.

With these objects in view, as well as other objects which will appear in the course of the specification, reference will be had to the drawing, wherein:

FIG. 1 is a fragmentary side elevational view of the forward end portion of a shotgun barrel, with a sight embodying the present invention mounted thereon,

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FIG. 2 is an enlarged fragmentary sectional view taken on line II--II of FIG. 1,

FIG. 3 is a view similar to FIG. 1, showing the sight mounted on a gun including a ventilated sighting rib,

FIG. 4 is an enlarged fragmentary sectional view taken on line IVIV of FIG. 3, and

FIG. 5 is a fragmentary sectional view taken on line VV of FIG. 2.

Like reference numerals apply to similar parts throughout the several views, and the numeral 2 applies to the barrel of a shotgun, only the forward end portion of said barrel being shown. The sight forming the subject matter of the present invention is indicated generally by the numeral 4, and is mounted at the top of the barrel immediately adjacent the forward end thereof. Said sight includes a mount 6 and a plug 8. Mount 6 is formed of metal, and has the form of an elongated, upwardly opening channel extending parallel to the axis of the barrel. It includes a planar base 10 having an upright vertical side wall 12 along each of the respective longitudinal edges thereof. Base 10 is provided centrally with a downwardly extending threaded lug 14. When the sight is to be mounted directly on a gun barrel, as in FIGS. 1, 2 and 5, lug 14 is screwed into a tapped hole 16 provided therefor in barrel 2, so that the lower surface of mount base 10 rests directly on the barrel as shown. In FIGS. 3 and 4, the shotgun is provided with a ventilated sighting rib 18 which, as well understood in the art, comprises a metal bar extending the length of the barrel in spaced relation thereabove, the primary purpose of which is to interrupt the shimmering heat waves which arise from a hot gun barrel, whereby to provide a clear line of sight. Said rib may be attached to the barrel by a series of posts, one of which is shown at 20, said post being brazed or otherwise secured at its lower end to the barrel, and being provided at its upper end with a dovetail head 22 engaged in a correspondingly shaped groove 24 formed in the lower surface of the rib. In guns equipped in this manner, lug 14 of the sight mount is screwed into a tapped hole 26 formed therefor in the rib, so that mount base 10 rests directly on the upper surface of the rib. If the lug 14 projects slightly into barrel 2, as shown in FIGS. 2 and 5, or into rib groove 26, the projecting portion may be ground off if desired.

Plug 8 is formed of a plastic or other transparent or translucent material having a high light refraction index, and is generally cylindrical in form, having hemispherically curved end portions 28. The length of the cylindrical portion thereof corresponds to the longitudinal length of mount base 10, and a notch 30 is formed in the lower surface of said plug for engaging the mount base. Longitudinally of the lug, the length of notch 30 is equal to the length of the cylindrical portion thereof, and hence equal to the length of the mount base. Vertically, the depth of the notch is equal to the vertical thickness of the mount base. Hence when the plug is placed in the mount so that notch 30 engages the mount base, the hemispherically curved end portions 28 of the plug will appear to rest directly on the gun barrel, as in FIGS. 1, 2 and 5, or directly on rib 18, as in FIGS. 3 and 4. The diameter of the plug is equal to the spacing between side walls 12 of the mount. Said side walls extend above the axis of the plug, and the upper edge portions 32 thereof are rolled inwardly as best shown in FIGS. 2 and 4 to secure the plug in assembly with the mount. The upper portion of the plug which is exposed between the upper edges of side walls 12 has a continuous series of peripheral grooves 34 formed therein.

In operation, light striking the exposed surfaces of the plug from a generally forward angle will be partially refiected therefrom and will partially enter therein, and that part of the light which enters tends to be trapped therein,

as previously described, by internal reflection resulting from the high refractive index of the plug material, until it reaches the rearward end of the plug where it emerges therefrom since it strikes the internal surfaces at said end at angles too obtuse for internal reflection, thereby giving the appearance ofabrightly. glowing head of @which is of material assistance in the operation of sighting the gun. The grooves 34 have been found to be of material assistance in providing a brighter light, even on very dull and cloudy days, apparently because they provide a much greater surface area, namely the forwardly facing walls of the grooves, which is disposed more nearly normal to the axis of the plug, so that a greater portion of the light in this direction enters the plug rather than being reflected externally therefrom. The shape of the grooves should be such that the forwardly facing walls formed thereby direct light entering therethrough angularly toward the opposite side of the plug for internal reflection at the opposite side rather than directing it parallel to the plug axis toward the next groove, where it would merge and be lost. For this reason, square grooves forming walls at right angles to the plug axis have been found relatively ineffective. At the same time, the forwardly facing walls of the grooves should not be so acutely angled to the plug axis that light entering them is directed to the opposite side at such an angle as to emerge therefrom rather than being internally reflected. Tests indicate that these groove walls should be inclined to the plug axis at an angle of at least 45 degrees. V-shaped grooves with a total included angle of 60 degrees, as shown, have been the most effective yet tested, but this is not intended as restrictive. Providing the inner surfaces 36 of base and side walls 12 with a high polish also increases the brightness of the sight, as they will then reflect and return to the plug at least a portion of the light which would otherwise be lost.

Notching the plug at 30 to receive mount base 10 therein, so that the head of light afforded by the sight appears to rest directly on the gun barrel, or on the surface of sight rib 18, greatly reduces, and in the case of a sight mounted directly on the barrel entirely eliminates, the necessity of bending or realigning the barrel to compensate for elevation of the sight which usually results from the mounting of a sight of this type. Nor is the lower part of the light head as viewed by the gunner darkened by the presence of mount base 10 therebehind. The plug extends well behind the mount, and the extending portion is hemispherically curved. This curvature diffuses the available light thoroughly throughout the entire height of the plug. It has been found that so long as the rearwardly extending portion 28 of the plug is of at least full hemispherical extent, and so long as the vertical thickness of mount base 10 is no more than about onethird the radius of the plug, there will be no apparent darkening of the lower portion of the light bead as viewed by the gunner.

While I have shown and described a specific embodiment of my invention, it will be readily apparent that many minor changes of structure and operation could be made Without departing from the spirit of the invention as de fined by the scope of the appended claims.

What I claim as new and desire to protect by Letters Patent is:

l. A gun sight comprising:

(a) a generally cylindrical plug of translucent material having a light refractive index, and means for mounting said plug rigidly relative to a gun barrel with its axis generally parallel to the axis of said barrel and with at least a portion of its cylindrical surface exposed, said exposed surface having a series of grooves formed peripherally therein, said mounting means including a channel-shaped mount of substantially U-shaped cross-sectional contour having a planar base and a pair of parallel side walls disposed respectively at opposite sides of said base, said base being adapted to engage the barrel of said gun directly, said plug being disposed longitudinally in said mount and having one end thereof projecting outwardly from said mount, said plug having a notch formed in the lower portion thereof receiving the base of said mount, the vertical depth of said notch corresponding to the vertical thickness of said base so that the projecting end portion of the plug, when viewed axially of said plug, appears to rest directly on said gun barrel.

2. A gun sight as recited in claim 1 wherein the projecting end portion of said plug is hemispherically rounded.

3. A gun sight as recited in claim 1 wherein the projecting end portion of said plug is hemispherically rounded, and wherein the vertical thickness of said mount base is no greater than about one-third of the radius of said plug.

References Cited by the Examiner UNITED STATES PATENTS 2,181,081 11/39 Ganaway 33-52 X 2,610,405 9/52 Dickinson 33-47 2,706,335 4/55 Munsey 33-47 2,727,309 12/55 Jenkins 33--52 2,911,724 11/59 Conant 3352 3,040,168 6/62 Stearns 2401 X ISAAC LISANN, Primary Examiner.

Claims

1. A GUN SIGHT COMPRISING: (A) A GENERALLY CYLINDRICAL PLUG OF TRANSLUCENT MATERIAL HAVING A LIGHT REFRACTIVE INDEX, AND MEANS FOR MOUNTING SAID PLUG RIGIDLY RELATIVE TO A GUN BARREL WITH ITS AXIS GENERALLY PARALLEL TO THE AXIS OF SAID BARREL AND WITH AT LEAST A PORTION OF ITS CYLINDRICAL SURFACE EXPOSED, SAID EXPOSED SURFACE HAVING A SERIES OF GROOVES FORMED PERIPHERALLY THEREIN, SAID MOUNTING MEANS INCLUDING A CHANNEL-SHAPED MOUNT OF SUBSTANTIALLY U-SHAPED CROSS-SECTIONAL CONTOUR HAVING A PLANAR BASE AND A PAIR OF PARALLEL SIDE WALLS DISPOSED RESPECTIVELY AT OPPOSITE SIDES OF SAID BASE, SAID BASE BEING ADAPTED TO ENGAGE THE BARREL OF SAID GUN DIRECTLY, SAID PLUG BEING DISPOSED LONGITUDINALLY IN SAID MOUNT AND HAVING ONE END THEREOF PROJECTING OUTWARDLY FROM SAID MOUNT, SAID PLUG HAVING A NOTCH FORMED IN THE LOWER PORTION THEREOF RECEIVING THE BASE OF SAID MOUNT, THE VERTICAL DEPTH OF SAID NOTCH CORRESPONDING TO THE VERTICAL THICKNESS OF SAID BASE SO THAT THE PROJECTING END PORTION OF THE PLUG, WHEN VIEWED AXIALLY OF SAID PLUG, APPEARS TO REST DIRECTLY ON SAID GUN BARREL.