US 2391473 A
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Dec. 25, 1945. c. F. MULLEN AUTCMATIC CONTROL FOR FIREARMS Filed Nov. 25, 1942 INVENTOR C/zaries F/Vuflen BY I ATTQRNLY Patented Dec. 25, 1945 AUTOMATIC CONTROL FOR FIREARMS Charles F. Mullen, Long Branch, N. J., asslgnor to Central Aircraft Corporation, Keyport, N. J., a corporation of Delaware Application November 25, 1942, Serial No. 466,912
The present invention relates to means for controlling the operation of firearms, and more particularly to means for automatically controlling the firing of adiustably mounted guns carried by aircraft.
One of the chief difiiculties to be contended with and overcome in adjustably mounting guns on aircraft is that of avoiding the accidental hitting of parts of the aircraft on which the guns are mounted. With guns that are fixedly mounted the problem is easily overcome as the gun may be synchronized to fire through a moving part; that is, the gun is mechanically geared and fired only when the moving part is out of the line of fire. The problem is more difiicult in connection with flexibly mounted guns adapted to be aimed and fired by a gunner. While swingin a gun in a path to follow a target, parts of the gunners own airplane may come into the line of fire and be seriously damaged or shot away. During the excitement of a battle the gunner should be free from having to worry about hitting parts of his own airplane. One way of overcoming this difiiculty in connection with flexibly mounted guns is by camming" them. With this method, a form of cam surface is utilized to so guide the gun or its mount at certain portions of its path, that it cannot come into line with and shoot at a part of the aircraft which carries the gun. This method is objectionable for it frequently requires relatively complicated mechanism, is likely to suddenly and unexpectedly throw the gunner off his aim, and it may increase the area of a blind spot due to the fact that where several comparatively small parts are grouped relatively closely together, a single cam means must be utilized to cause a gun to miss all of the parts as an entirety; it would be impractical to control the gun by a number of cams so that the gun would separately miss each of the closely positioned parts.
The present invention aims to overcome or minimize the above and other difficulties by providing a relatively simple means adapted to control a gun so that it will not shoot while aimed at some object other than a target, and which does not suddenly and unexpectedly throw a gunner oil his target. The invention also contemplates the provision of automatic gun controlling grouped separate parts, instead of avoiding such parts as a single group as is done in the usual camming of guns.
An object of the present invention is to provide a new and improved gun controlling means.
Another object of the invention is to provide means which may be used to avoid hitting closely a gun controlling means which is automatic in operation.
Another object of the invention is to provide a gun controlling means adapted to automatically stop the firing of the gun when it is aimed at a predetermined obstruction.
Another object of the present invention is to provide a gun controlling means adapted to automatically start the firing of a gun when its aim is directed away from an obstruction.
Still another object of the invention is to provide a gun controlling means which is relatively simple in construction and operation and which is easy to install.
A still further object of the invention is to provide a gun controlling means which does not throw a gunner out of a normal path of aim.
Other and further objects of the invention will be obvious upon an understanding of the illustrative embodiment about to be described, or will be indicated in the appended claims, and various advantages not referred to herein will occur to one skilled in the art upon employment of the invention in practice.
A preferred embodiment of the invention has been chosen for purposes of illustration and description and is shown in the accompanying drawing, forming a part of the specification, wherein,
Fig. 1 is a top plan view showing a gun mounting arrangement in an aircraft;
Fig. 2 is an elevational view, partly diagrammatic, showing a preferred embodiment of the invention;
Fig. 3 is a view of a screen adapted to be utilized in connection with controlling a firearm;
Fig. 4 is an elevational view, partly in section, showing one means for controlling the operation of a firearm; and
Fig, 5 illustrates a preferred wiring diagram for the controlling means illustrated in Fig. 4.
Referring again to the drawing and more particularly to Fig. 1 thereof, there is shown an airplane I having tail booms 2 and 4 carrying adjacent their ends a horizontal controlling surface 5 and spaced, vertical controlling surfaces 1 and 8. A flexibly mounted gun I0 is shown located in a turret positioned adjacent the trailing edge of a wing and intermediate the tail booms of the airplane I. This location of the gun serves to illustrate the present invention, but it will be clear that the invention is equally applicable to guns mounted at any other location on an aircraft. The chief function of the flexible gun I0 is to protect the airplane I from attack by an enemy airplane approaching from the rear of the airof his own plane. Figs. 1 and 2 illustrate, by dot-' ted lines, the danger areas within'which a gun ner might hit his own plane. Causing the gun or its mount to follow or'be guided by a cam track at such danger areas presents the diflicul- Y ties referred to hereinabove.
In Fig. 2 the gun I and tail surfaces and I of an aircraft are shown diagrammatically to clearly bring out the present invention. The flexible gun I 0 is intended to represent guns generally as the invention is not limited to use with any particular type of gun. A light-sensitive photocell II is preferably secured to the gun IE3 adjacent 'the'breech thereoflso that moving the gun to aim it correspondingly moves the ph0t0- cell I I. The photocell I I .is connected with suitable amplifier relays and th latter are operatively connected with a mechanism on the gun adapted to render the gun inoperative when it is pointed at obstructions such as the tail surfaces 5,! and 8. The'gun controlling mechanisms will be more fully described hereinafter.
The gun controlling photocell II is set into operation by means of light rays from alight source [4, which pass through suitable apertures or slits I9,.20, and 22 of a screen I3. The light source It maybe an electric bulb of appropriate size .and brilliance. The light source I4 is preferably contained within a box or receptacle l6 positioned adjacent the gun I 0 and photocell II. The box It may vbe mounted on a pedestal ,I! which is stationarily secured to the airplane I, since its relation to obstructions to be avoided by gunfire isconstant. The screen I3, however, is preferably mounted so that it may be moved vertically'in' proportion to the height to which the gun Ill may be adjusted. The screen I3, through which pass the light rays given off by the light source I4, is preferably an opaque material having'apertures or slits I9, and 22 through which the light rays may pass. A reflecting back may be utilized in the box I 6 to direct a maximum amount of light from bulb I4 through the screen apertures toward the photocell I I. The apertures I9,,2li and 22 are a pattern or representation of the obstruction which it is desired to protect from gunfire. In the present instance the apertures of the screen I3 are shown in the shape of the airplane tailsurfaces which are to be protected from shots fired by the gun II). The slits should be wide enough to allow for movement of the con trolling surfaces 5, 1 and '8 during flight.
The horizontal aperture or. slit-I9 in the screen of Fig. 3 represents the tail booms 2 and 4 and the horizontal tail surface 5 of the airplane and the vertical apertures or slits 20 and '22 represent the vertical tail surfaces I and 8 of the airplane. The screen I3 is so positioned, with respect to the photocell carried. by the gun, that when the gun I0 is not aimed at anyof the tail surfaces the photocell II willbe opposite an opaque section 23 of the screen; the gun will then be firing normally. 'When the gun I!) is aimed at any of he ail su a s t e h to ll. w ll e n l n with one of the apertures or slits representing a portion of the tail surfaces. In this latter position, a current will be set up through various amplifyingrelays I8 connected with the photocell and these will in turn effect operation of a mechanism for stopping the operation of the gun. It will be understood that any desired shapes and sizes of designs or patterns may be carried by the screen I3, depending upon the shapes and sizes of the obstructions which it is desired to avoid hitting by gunfire. The amplifying relays, circuit connections, et cetera, are not illustrated in detail herein since they are generally known and do not form the subject matter of the present invention. Current for operating the light source [4, amplifying relays, and other parts of the device may be supplied to the plug connections 9 j and I2 from a battery or generator (not shown).
A gun may be rendered inoperative in numerous ways when pointed at an obstruction. For illustrative purposes, there will now be described one way of controlling a gun by a type of auxiliary trigger, the latter being in turn operated by the photocell II. Figs. 4. and 5 illustrate the details of such a construction applied to a, fully automatic, gas operated machine gun of the Lewis type. The Lewis type has beenselected since the features of its construction and operation are known and a description of its automatic operation when embodying the present invention will serve to clearly illustrate one method of ,controlling the operation of such guns. The first shot from such types of guns is fired by pulling :back on the trigger 28 to release a lever 29 from a notch 3! on the gas actuated operating rod 32 of the gun. Moving the lever 29 out of the'notch 3i of the operating rod 32 causes the operating rod 32 to be impelled forwardly by a spring 34. The operating rod 32 carries a firing pin 35 which is thrown against a cartridge 36 to fire it. The gas charge resulting from a first shot'effects return of the operating rod 32 and firing pin 35 to a rearward position in the gun and also re-. winds or compresses the actuating spring 3 l; the actuating spring 34 thereupon, again throws the operating rod and firing pin forwardly; against a new cartridge; whichhasautomatically been inserted into the breech of the gun. ,The firing of the gun will continue until the ammunition gives out or until the gunner releases the trigger 28. Releasing the trigger 28 -allowsthe spring 37 to move the lever 29 into engagement with the notch 3I of the operating rod -$2 and to thus hold back the firing pin 35. The present invention provides a detent member or augiliarytrigger 38 adapted to fit into the notch 2! of the operating rod 32 to stop the operation of the gun when the photocell is affected bylight rays which pass through the apertures orslits in the screen I3. The detent or auxiliarytrigger 38 may be of the solenoid type and may operate in dependently of the main trigger 28. q Movement of the gun It! into line with anylof the'tail surfaces 5, "i or 3 causes corresponding movement of the photocell II carrie'dthereby and alignment thereof with a screen aperture 'or slit I9, 22') or 22 corresponding to one ofthetail surfaces. Light rays passingthrough one'fdf-the screen slits onto the photocellis'eifectiv'e tolfset into operation the amplifyin relays connected therewith. The amplified current flowsthrou gh the solenoid coil 40 and projectsthedetent or auxiliary trigger 38 outwardly into, engagement with the notch 3! in the operating rod 32 of; the gun, This holds the operating rodand firing pin and thus stops the operation of the gun. When the gun has swung out of line with a tail surface or other obstruction the photocell H and the screen slits will be out of alignment with each other and current through the solenoid will immediately cease. A spring 4| may then move the detent or auxiliary trigger 38 out of the notch 3! so that the gun may immediately commence firing again, The stopping and starting of the gun are practically instantaneous and the tail surfaces are effectively protected from being hit by shots from the gun.
Vibrations of the gun due to firing do not affect the operation of the present gun controlling device. If the gun vibrates to a position such that the photocell H does not line up with a screen slit, the gun will then also be out of line with a surface to be protected and may be fired without danger. However, any vibration of the gun which causes the photocell H to line up with screen slit will automatically stop the operation of the gun.
The above described means and method of controlling a flexibly mounted gun may be applied to guns of various types and sizes. Also, any other suitable auxiliary trigger mechanism or the like may be utilized. It is believed that the operation of the present device will be clear from the foregoin detailed description and that further description of the operation at this point would be superfluous.
While the preferred embodiment illustrates the present invention applied to a single gun, the invention is applicable to a plurality of guns operated either jointly or independently. For example, four guns may be mounted at the corners of a square of suitable dimensions. The distance the guns are spaced may be such that continuous firing is obtained and that the obstruction will be in the line of fire of only part of the guns at any one time. Hence some of the guns will be firing at all times. By locating the guns at th corners of a square, for example, both the lateral and vertical obstructions may be by-passed without stopping the firing of all of the guns. Other desired arrangements are also intended to be included in the concept of the invention.
It will be seen that the present invention provides a new and improved means and method for controlling the operation of flexibly mounted guns so that a gunner will not accidentally shoot at obstructions which may come into the line of.
fire. This device is particularly useful in connection with aircraft. No complicated mechanism of cams, levers, et cetera, is used to control the gun. A gunner may swing a gun smoothly herein is to be interpreted as"illustrative"and not i along a path of fire without being suddenly stopped or thrown out of a natural path of fire by a cam while attempting to follow the course of a moving target. The usual manually controlled trigger of a firearm may be held continuously in firing position by the gunner and the gun will automatically cease firing when pointed at an obstruction and will immediately commence firing when the obstruction is out of the line of fire. The device is relatively simple in construction and easy to install.
As various changes may be made in the form, construction and arrangement of the parts herein without departing from the spirit and scope of the invention and without sacrificing any of its advantages, it is to be understood that all matter in a limiting sense.
Having thus described my invention, I claim:
1. In a device of the class described for use in an airplane, the combination of a firearm, means mounting said firearm for rotation about a vertical axis and about a horizontal axis, a light sensitive photocell mounted on said firearm at a distance from said horizontal and vertical axes, an enclosed light source spaced from said photocell and fixed with respect to said mounting and comprising a screen having an opaque portion and a light transmitting portion, said light transmitting portion having a contour constructed, positioned and arranged to direct light on said photocell when parts of the airplane are in the line of gun fire and means operatively connected to the photocell to render the firing mechanism inoperative while light is directed on said photocell. c
2. In a device of the class described for use in an airplane, the combination of a firearm, means mounting said firearm for rotation about a vertical axis and about a horizontal axis, a light sensitive photocell unit, an enclosed light source unit spaced from said photocell unit and comprising a screen having an opaque portion and a light transmitting portion, one of said units being fixed with respect to said mounting and the other of said units being mounted on said firearm at a distance from said horizontal and vertical axes, said light transmitting portion of the screen having a contour constructed, positioned and arranged to direct light on said photocell unit when parts of the airplane are in the line of fire, and means operatively connected to the photocell unit to render the firing mechanism inoperative while light is directed on said photocell unit.
CHARLES F. MULLEN.