US2336718A

US2336718A - Luminous gun sight

Info

Publication number: US2336718A
Application number: US359649A
Authority: US
Inventors: Davis George Howlett
Original assignee: Individual
Current assignee: Individual
Priority date: 1940-10-04
Filing date: 1940-10-04
Publication date: 1943-12-14
Anticipated expiration: 1960-12-14

Description

Patented Dec. 14, 12943 LUMINOUS GUN SIGHT George Howlett Davis, Detroit, Mich.

Application October 1940, Serial No. 359,649

9 Claims.

This invention relates to sighting devices for firearms and in particular to luminous gun sights for use at night or in dark places, or where the light is dim.

One object of this invention is to provide a luminous gun sight for firearms and having means for optically projecting upon the target a luminous pattern such as cross lines, a circle, or other indicia at the point of impact of the bullet at the end of its trajectory.

Another object of the invention is to provide a luminous gun sight as set forth in the preceding object wherein the device is self-contained and compact, and is attachable or detachable at will from the gun.

Another object is to provide a luminous gun sight as set forth in the preceding object wherein a spot on the target is brilliantly illuminated by reason of the use of a source of electricity, such as a battery, which supplies voltage considerably in excess of the rated voltage of the light bulb filament.

Another object is to provide a luminous gun sight attachable to the gun at a point immedii ately beneath the barrel, thereby enabling the gun and gunsight to be inserted in a compact holster, as well as locating the gun sight in a position where it is not in the way of the user if he desires to use the regular sights on the top of the gun.

Another object is to provide a luminous gun sight, all parts of which are self-contained, in a compact casing mounted beneath the barrel of the gun in the vicinity of the muzzle, thereby making the gun muzzle-heavy, a condition which pistol experts generally favor for accurate shooting, in contrast to a muzzle-light condition.

Another object` is to provide a luminous gun sight having a gravity-responsive switch, such as a mercury switch, for automatically energizing the gun sight as the gun is raised into aiming and firing position, but de-energizing the gun sight when the gun is lowered or is maintained in a lowered position, as in a holster, or when held at the users side.

Another object is to provide a luminous gun sight as set forth in the object immediately preceding, wherein a safety switch is provided in series with the gravity-responsive switch, the safety switch being operated by. the holster to cie-energize the electrical system, thereby preventing the gun sight from becoming illuminated when the gun is laid on a shelf or table in a horizontal position in its holster, thereby saving current.

Another object is to provide a luminous gun sight as set forth in the two objects immediately preceding, wherein an additional hand-operated switch is provided to by-pass the gravity-responsive switch so that in an emergency the user can switch on the luminous gun sight when he must shoot downward, as in shooting down a stairway, downhill, or from a roof or window.

In the drawing:

Figure 1 is a central vertical section. through a preferred form of the luminous gun sight of this invention.

Fig. 2 is a top plan view of the luminous gun sight shown in Figure 1.

Figure 3 is a front elevation of the luminous gun sight shown in Figure 1.

Figure 4 is a rear elevation, partly broken away, of the luminous gun sight shown in Figure 1.

Figure 5 is a horizontal longitudinal section taken along the line 5-5 in Figure 1.

Figure 6 is a fragmentary vertical cross-section taken along the line 6 6 in Figure 1.

Figure 7 is a similar View of a modification of a portion of Figure 6, showing a modified reticule or sighting indicia.

Figure 8 is a diagrammatic View of the electri- Y cal circuit of the luminous gun sight of this invention.

Figure 9 is a side elevation partly in section showing the luminous gun sight attached to a pistol of the revolver type.

Figure 10 is a top plan view of the arrangement shown in Figure 9.

General arrangement In general, the luminous gun sight in the preferred form of this invention consists of a compact casing attachable to the barrel or forward portion of a gun and containing an optical projection system with batteries for supplying current to energize the electric lightbulb used as the source of light for the projecting system. The luminous gun sight is attached to a pistol of the revolver type by sliding a tubular portion over the barrel of the pistol and rotating it until the front sight of the pistol locks against an abutment.

The optical projecting system consists of a condensing lens having a reticule, preferably etched thereon, or optionally, upon a separate plate or using separate cross-wires. Optionally, also, a light filament itself may be used as the reticule, or sighting index. The optical system is also provided with one or more objective lenses for projecting the image of the reticule upon the target. The axis of the optical system is arranged at an angle to the axis of the gun bore so that any errors of parallax, drift or other deviation may be compensated for.

The optical system also contains an electric light bulb which serves to illuminate the reticule. The filament of the electric light bulb is energized by one or more battery cells, these battery cells supplying a voltage which is considerably in excess of the rated voltage of the filament. By this means the electric light bulb is caused to deliver a much more brilliant illumination than is possible in using a bulb of the same rated voltage as the voltage of the batteries. Thus the life of the light bulb lament is necessarily shortened, but this shortening is not serious when it is remembered that the gun sight is used only intermittently for short periods of time. Under such circumstances, it has been proved experimentally that the light bulb lament has a life far longer than its life for steady burning at the excess voltage at which it is operated.

The energization of the light bulb is controlled by a gravity-responsive switch, such as a mercury switch, so arranged that the circuit is broken when the gun is pointed downward, but closed when the gun is raised. With this arrangement, the user, such as a policeman, watchman or soldier, does not need to disclose his position until the instant he is ready to re, and the gun sight becomes illuminated automatically when he raises the gun to fire.

In order to avoid the waste of current when the gun is placed in a horizontal position in its holster, an additional safety switch is provided in series with the gravity-responsive switch so that engagement with the holster opens this switch and cle-energizes the electrical system. Optionally, an additional hand-operated switch is provided for by-passing the gravity-responsive switch or mercury switch so that the user can employ the luminous gun sight in shooting downward, as down hill, down a stairway, or from a roof or upper window.

Construction Referring to the drawing in detail, Figures 1 to Il show a preferred embodiment of the luminous gun sight of this invention as housed in a casing l, preferably of metal or molded plastic material. The casing IG is provided with an upper bore ll, a lower bore l2, and intermediate bores i3 and lil running longitudinally therethrough. The casing lil is provided with front and rear closure plates i5 and I6 held together by a longitudinal screw il threaded into thel threaded bore I 8 in the rear plate. In order to prevent short-circuiting the electrical system, it is preferable that the rear plate i6 shall be of insulating material, or that the screw l1 shall be insulated from one of the plates l5 or I6.

The casing lil is provided with an upper projection I9 to which is secured a tubular member 20 as by the bolts or rivets 2l (Figure l). The tubular member 2li is provided with a longitudinal slot 22 offset from the vertical and communicating with a set-back portion 23 having an abutment 2li forming a part thereof. In attaching the device to a pistol of the revolver type, the tubular portion 2) is slid over the barrel of the revolver with the front sight of the gun passing through the slot 23 and coming to rest in the offset portion 23 against the abutment 24 as'the device is rotated into its working position, rlhe tubular member 26 is also provided with an access hole 25 to prevent the insertion of a screw driver for tightening or loosening the bolts 2l.

The upper bore I i serves to receive the optical projection system. This consists oi a convex condensing lens Zd having a reticule 2l associated therewith. The reticule 2l may consist of cross lines 28 (Figure 6) either alone or associated with a circle 253 (Figure '7). Other indicia may be employed in the reticule 2l, as desired by the user or as'adapted to the particular conditions under which the gun sight is to be used.

The optical system also contains a convex objective lens 3l) having its principal focus coinciding with the cross-lines 28 of the reticule 2l.

The cross-lines 28 may be conveniently etched upon the rear surface of the condensing lens 255 Ior placed upon a separate plate, as is most convenient. The condensing lens 25 and objective lens 3S are separated from each other maintained in accurate positions relatively to each other and to the source of illumination by spacing tubes 3|, 32 and 33, the latter being in abutting relationship with the front closure plate l5.

The source of illumination consists of an electric light bulb 3d having a filament 35 and a tubular base 5?. The latter is permanently secured within a holder 3l' of disk-like form by means 30 of a metallic insert 33. The metallic insert 33 is preferably of low melting alloy, such as an alloy of bismuth and antimony or solder.

The purpose of the metallic insert S3 is to enable the :filament to be accurately located ex- 35 actly in the axis of the cylindrical outer surface 3S of the holder El. Ordinarily, the filaments 35 of light bulbs are often eccentric to their bases 36 so that accurate adjustment relatively to the axis of an optical projecting system varies with the particular bulb. In the present invention, the bulb 34 is seated in the holder 3'! by means of a jig in the laboratory of the manufacturer of the gun sight and adjusted until the filament 35 is exactly co-axial relative to the outer surface 39 o the holder 3l, after which the useable metal S3 ,is allowed to solidify. This arrangement increases the optical accuracy of the projecting system,

The electrical system by which the lainent 35 is energized consists of a pair of battery cells 40 inserted in the lower bore I2. The central pole lil of the rearward cell il@ is in engagement with the metallic casing d2 of the forward cell, whereas the central pole lll of the forward cell is in engagement with the forward plate l5. Contact is made with the casing i2 of the rearward cell lil by means of a spring member d3 which is provided with an aperture M surrounding the screw il and preventing contact therewith. rlhe upper end of the spring member 43 is secured to the holder Sl, which is of conducting material and which is held in position by the set screw d5 passing through a hole in the casing IG and having its threads engaging a threaded hole 46 in the holder 3l. The fuseable metal 38 establishes a circuit between the holder Si and the base 3S of the light bulb 3d.

Secured to the central pole 41 of the light bulb 34 is a conductor d8 which passes downward (Figure 4) through an aperture d and through the intermediate bore lil to the rear pole 5i of a gravity-responsive mercury switch 52. The rear pole 5l is insulated as at 53 from the switch casing 5d, which contains a quantity of mercury 55. Thev switch casing E4 is slidably mounted in a bore enlargement 55 and is urged toward the forward end thereof into engagement with the front closure plate l by a coil spring 5l. The switch casing 54 is provided with a forward projection 53 which projects through an aperture 59 in the front closure plate l5. Consequently, the closure plate l5 completes the circuit, as shown in Figure 8, between the battery cells t2 and the light bulb filament 35, except when the device is in a vertical position or when the projection 58 and the mercury switch 52 are pushed backward as by engagement with the holster. When either of these situations occurs, the circuit is broken and the lament 35 remains deenergized.

Optionally, an additional switch is provided for by-passing the mercury switch 52 and establishing a Contact between the front closure plate l5 and the conductor d8. The purpose of this manually operated switch is to enable the lament 35 to be illuminated when the police ofiicer or other user finds it necessary to shoot downward from an elevation. Without this manual switch, the filament 35 cannot be energized when the gun is pointed downward and is only energized when the gun is raised toward a horizontal or upward vertical position.

This manual switch 63 is pivotally mounted on the rear end of the screw i7, and is engageable with a spring contact Sli, the inner end of which engages the central pole lil of the light bulb 34. This enables the bulb 34 to be energized, regardless of the position of the mercury switch 52.

Operation In the operation of the luminous gun sight of this invention, it is assumed that the batteries i2 have been loaded into the lower bore l2 and the end closure plates i5 and i5 secured in the positions shown in Figure l. The circuit is now complete except for its possible interruption by the mercury switch 52.

The device is attached to the gun by sliding it over the barrel with the front sight passing through the slot 22 into the cutaway position 23 as described above. Obviously, suitable means of attaching the device to an automatic pistol or to a rie, shotgun or sub-machine gun will be evident by slight modifications of this arrangement.

The holster for the gun is preferably made in substantially rectangular shape so that it will accommodate the device in its position upon the gun. When the gun and luminous gun sight are thus assembled, as in Figure 9, and secured in the holster, the contact with. the bottom wall of the holster pushes the projection 53 and switch 52 inward out of contact with the end closure plate iii. This breaks the electrical circuit and prevents the lighting of the lament 35 of the bulb Se even though the gun and its holster are laid in a horizontal position. As soon as the operator removes the gun from the holster, however, the coil spring 51 pushes the mercury switch 52 to the left, bringing its front edge into engagement with the end closure plate l5 and conf ditioning the circuit for closure as soon as the gun is raised.

As long as the user keeps the gun lowered, the mercury in the mercury switch 52 is out of contact with the switch pole 5i and no current can iiow to the light bulb lament 35. Thus, a police ofcer, watchman, detective or soldier does not need to disclose his position to a possible criminal or enemy while he is waiting for a favorable opportunity to act. If, however, he finds it necessary to use the gun, he merely raises it to a horizontal position in the natural act of sighting the gun. As he does this, the mercury 55 ows into contact with the switch pole 5i and closes the circuit shown in Figure 8, causing the light bulb lament to become illuminated. This causes an image of the reticule 2l with its cross lines 23 to be projected upon the distant target, with the cross lines intersecting at the point where the bullet will strike. The user may thus raise his gun and fire, lowering it quickly before his opponent has an opportunity to sight accurately and fire. Moreover, the user can hold the pistol around one side of an obstacle such as a barrel or tree while he peers around the opposite side, thereby deceiving the opponent into thinking that he is behind the gun instead of to one side of it.

Moreover, the use of batteries d2 which supply voltage considerably in excess of the voltage rating of the light bulb filament 35 causes a brilliant illumination to occur and the cross lines 23 to be sharply seen on the target against a bril liant circular patch of light. This feature gives the device great superiority over previously used devices where the dimness of image and the lack of contrast greatly interfered with the accuracy of shooting.

Figure 9 shows the relationship of the axis 6i! 'of the gun bore as compared with the axis Si of the optical system of the gun sight. The axis Si is seen to be angled upward slightly so as to compensate for parallax, drift and other errors of trajectory. The angle of inclination between the axes and 5I in Figure 9 is somewhat exaggerated to indicate the principle more clearly. Obviously, the trajectory of the bullet will also have much influence upon the adjustment of the luminous gun sight, especially if it is adjusted for shooting at distances greater than the ordi nary distances, or is used with cartridges having low ballistic characteristics.

While I have shown and described my invention in detail, it is to be understood that the same is to be limited only by the appended claims for many changes may be made without departing from the spirit and scope of my invention.

What I claim is:

1. In a luminous gun sight, an electric light source, a sighting element associated therewith, an optical system arranged to project an image of said sighting element to a distant location, means for supplying electricity to said light source, gravity-responsive means for interrupting the circuit between said light source and said electricity-supplying means in response to the lowering of the gun sight from a raised position, and means for selectively closing said circuit independently of said gravity-responsive means in the lowered position of the gun.

-2. In a luminous gun sight, an electric light source, a sighting element associated therewith, an optical system arranged to project an image of said sighting element to a distant location, means for supplying electricity to said light source at a voltage materially in excess of the rated voltage of said light source whereby to increase brilliance of said distant image, a gun holster, and switch means operatively engageable with said holster for opening the circuit between said light source and said electricity-supplying means.

3. In a luminous gun sight, an electric light source, a sighting element associated therewith, an optical system arranged to project an image of said sighting element to a distant location, a gun holster and means automatically responsive to engagement with the gun holster object for cle-energizing said light source.

4.. In a luminous gun sight an electric light source, a sighting element associated therewith, an optical system arranged to project an image of said sighting element to a distant location, a gun holster, and switch means operatively engageable with said holster for opening the circuit between said light source and said electricitypplying means.

5. a luminous gun sight, an electric light source, a sighting element associated therewith, an optical system arranged to project an image said sighting element to a distant location, a gun holster, switch means operatively engageable with said holster for opening the circuit between said light source and said electricity-supplying means, and gravity-responsive switch means in series with said holster switch means for respectively clcsing and opening the circuit between said light source and said electricity-supplying means in response to the raising and lowering of the gun sight.

6. En a luminous gun sight, a casing having a hansb-er, an electric light source in said chamer, a sighting element and an optical projecting ystem arranged in said chamber for forming a distant image of said sighting element, an electric battery. a circuit interconnecting said battery d light source, switch means for selectiven ng and closing said circuit, and a tubular t therein longitudinally slidable over the barrel of a gun and having a slot therein for the passage ci" the front sight of the gun whereby to quickly attach and detach the gun sight from the gun barrel while maintaining accurate alignment therebetween.

7. ln a luminous gun sight, a casing having a plurality of adjacent elongated chambers, an electric light source in a rst chamber, a sighting element and an optical projecting system arranged in said first chamber for forming a distant image of said sighting element, an electric battery in a second chamber, a circuit interconnecting said battery with said light source, switch means for selectively opening and closing said circuit, and a tubular attachment member having a bore therein longitudinally slidable over the barrel of a gun and having means therein for the passage of the front sight o the gun, whereby to quickly attach and detach the gun sight from the gun bar rel while maintaining accurate alignment therebetween.

8. In a luminous gun sight, a casing having a plurality of adjacent elongated chambers, an electric light source in a first chamber, a sighting element and an optical projecting system arranged in said first chamber for forming a distant image of said sighting element, an electric battery in a second chamber, a circuit interconnecting said battery with said light source, switch means for selectively opening and closing said circuit, and an attachment member on said casing above said chambers having a bere for receiving a gun barrel and a slot for the passage of the iront sight of the gun, whereby t0 quickly attach and detach the gun sight from the gun barrel while maintaining accurate alignment therebetween.

9. In a luminous gun sight, a casing having a plurality of adjacent elongated chambers, an electric light source in a rst chamber, a sighting element and an optical projecting system arranged in said iirst chamber for forming a distant image ci said sighting element, an electric battery in a second chamber, a circuit interconnecting said battery with said light source, switch means for selectively opening and closing said circuit, and an attachment member on said casing above said chambers having a bore for receiving a gun barrel and a slot for the passage of the front sight `0f the gun, said slot having an offset portion for receiving said front sight in a locking position, whereby to quickly attach and detach the gun sight from the gun barrel while maintaining accurate alignment therebetween.

GEORGE HOWLETT DAVS.