US2534258A

US2534258A - Gun sight

Info

Publication number: US2534258A
Authority: US
Publication date: 1950-12-19
Anticipated expiration: 1967-12-19

Description

Dec. 19, 1950 D. v. GALLERY, JR

GUN SIGHT 5 Sheets-Sheet 1 Filed March 31, 1941 I I l lNVENTOR Z Gall? mag;

an/ze D. v. GALLERY, JR

Dec. 19,1950

GUN SIGHT 5 Sheets-Sheet 2 Filed March 31, 1941 lley'fn 96 ATTORNEY Dec. 19, 1950 D. v. GALLERY, JR

GUN SIGHT 5 Sheets-Sheet 3 Filed March 31, 1941 lllllllllllllll mnnmmnuununnlm .Iilllilulll INVENTOR 17am V Galley J".

ATTORNEY Dec. 19, 1950 D. v. GALLERY, JR 2,534,258

GUN SIGHT Filed March 31, 1941 s Sheets-Sheet 4 ELEVAT/O/V INVENTOR Y Dam eZ VGalle ryJn ATTORNEY Dec. 19, 1950 D. v. GALLERY, JR 2,534,258

GUN SIGHT Filed March 31, 1941 5 Sheets-Sheet 5 I TfZO.

INVENTCm BY flanz'el VGalleyJr:

Patented Dec. 19, 1950 UNITED PATENT OFFICE GUN SIGHT Daniel"; Gallery Jr., United StatesNavy Application March 31, 1941, Serial No. 386,090

(Grantedunderthe act' of March 3, 1883, as amended'April 30, 1928; 370 0. G 757) 1 Claim;

This invention. relates to automatically compensating gun sights for machine guns.

In firinga flexibly mounted, or turretmounted machine gun from a moving aircraft, a certain correction must be applied to theaim. of the gun to compensate for the velocityimparted to the projectile as a. result of the movement: of the aircraft. This correction is known as gunner deflection. The-magnitude of, the angle at. which thegun barrel is-oitset from the line of=sight to correct for the gunners deflection is dependent upon the'direction in which. the gun is pointed relative to the line of flight and uponthe air speed of the: firing aircraft.

, The fundamental principle: by whichthe correction iswobtained, which is. old inthe art, is to eifectan offset ofone oi two sighting; members.. Ininy inv'entidnl have perfected an automatic means. for offsetting. the forward sight, theoifsetbeing, alwaysin the direotionof motion "oi?v the/aircraft. lTheamount of thefoffset may be determined. by considering a simple parallelogram. formed by the. sighting. members: in which thedistance between the axisoff the forward and rear sighting member is. a function? of' the muzzle 'velocity'of. thebullet and. its direction is parallel to the axis of the bore of. the gun.' It, therefore, represents the component of motion (if the bullet due to the explosion of the' charge in the chamber of, the gun; Th'e-lengthof the offset of the forward sight from its axis is proportional'to thejsame function of velocity and represents the air speed of the craft andi'its direction. It' is at'all times parallel to the motion of' the aircraft, and is therefore the vector componentof the motion. of" the bullet due to the'-motion of'the craft. The line of sight as determined by the center of thetwo' sighting member's isthe resultant of thetwo" components andrepresentsthe direction and velocity ofthe bullet; dueto both forces.

This resultant is the desired sight line'to be 'laidpoint blank at the target; assumingth'e target to be'stationary and further 'assu'ming that th'edefi'ection of thebullet from its straight line path due to the force of" gravity acting on the bullet is so man" that it maybe disregarded; In ebtuar practice =--the sight line is corrected for the'speed'and direction' of' the target by means well knownto the art; however, correctionsfifor" the force of" gravity are seldom necessary, since the ranges' at' which these sights are effective "are "relatively short and the 'tra-jectoriesare substantially flat.

' 1 am: hereprim'arily concerned-with the correction for' gunner's deflection? and my invention? consists particul'arly in improvements of the prior art gun rsights; especially i the gun sights I" offthe typeillustratedand' described in' 'thelf; ,8;

flexibly mounted aerial 7 patent to Inglis, 1,650,628, to which a more particular reference will be made laterin this specification. I have also devised other means for introducing the correction for gunners deflection, which is madethesubject of my copending application No..-389,844, filed April 23; 1941-.

It is an object of my invention to provide a gun sight. having two sighting members, one of which is mounted on a pivoted arm so that the sight may be offset both laterally and longitudinally as the gun is moved in elevation or in train.

It is a further important object of this invention to provide an automatic adjustment for-'the movable sight. member which will-maintain the axis of the arm carrying the movable sighting member parallel to the fore and aft axis of-the aircraft, irrespective of the angle of elevation or-train of the gun relative to the axis;

It is. also a further objectof this invention to provide a means for easily and quickly adjusting the position of the sighting member relative to its support so that the length of-theofiset may be adjusted. to compensate for changing airspeeds of the aircraft.

It is another object of this invention to provide a gun sight whichautomatically compensates for gunners deflection inaturretmounted aerial machine gun.

It isan important feature-ofmy invention that the oifset of the sighting member always-be in a. direction of motion of the aircraft through the air, i. e., always parallel to its keelor longitudinal. axis, regardless of the position of the gun. The automatically adjusted gun sights of the prior art have failed to accomplish this specific purpose; For example, the corrections-in- -troduced. by the device illustrated in the patent to, Inglis, 1,650,628, are only approximately-correct over a limited. rangeof elevations andtrain, while the corrections introduced by the apparatus which constitutesmy' invention are correct for any angle of elevation or train. Certain constructional features of my invention which are designed to produce this result are novel, and while they do not. appear here asspecific objects of my invention, they re important and are made the subject matter of the appended claim.

With the foregoing and-other objectsin-view, the invention consists in the construction, combination and arrangement of parts hereinafter described and illustrated in the drawings, in which:

Fig. 1 is a side elevation of a ball type turret, as usedonaircraft, with parts'broken away to-show my invention as applied to a turret mounted aerial gun.

Fig. 2 is a vertical cross-section looking-from the front of the above 'turret, -showing the. drive mechanism'for the sight.

Fig. 3 is a detail cross-sectional view of the turret training gear and motor, showing also the outline of the fuselage shell.

Fig. 4 is a vertical, longitudinal, sectional view of the front sight.

Fig. 5 is a vertical, cross-sectional view taken on the line 55 of Fig. 4.

Fig. 6 is a side elevation of the front sight and shows same applied to a gun with stationary mount, whether upon aircraft, watercraft or land vehicle.

Fig. 7 is a diagrammatic view showing in plan the aiming of a gun equipped with the mechanical front sight, depicting the approach of the target 45 off the port bow.

Fig. 8 is a diagrammatic view showing in plan the aim for a target 30 off the port stern.

Fig. 9 is a diagrammatic view showing in elevation the approach of a target at 45 elevation ahead. In each of the diagrammatic views of Figs. 7, 8, and 9 the target is assumed to be stationary.

Fig. 10 is a front elevational view of a modification of my invention.

Fig. 11 is a side view of the modification illustrated in Fig. 10, and

Fig. 12 is a plan view of the modification as illustrated in Figs. 10 and 11.

Referring now to the drawings, in which Figs. 1, 2 and 3 illustrate my invention as applied to turret mount machine gun. The turret per se, which forms no part of my invention except as modified to incorporate the sight adjusting mechanism, is indicated generally at it In Fig. 1 part of the turret structure, including the windows H and channel shaped formers or frames l2 are broken away to show the gun mount and sighting mechanism. The fixed machine gun i3 is secured to the turret by means of the supporting brackets 2| and 22. The forward bracket 22 is secured to the channel former or frame 12 and to the forward gun mount adapter 23. The Y bracket 2| is secured to the gun at both the forward and

rear adapter

23 and 24 respectively, and to the base of the turret structure at !4.

The turret is supported at the bearing pedestal 25 so as to be rotatable about the lateral or elevational axis through the trunnion 51. The reversible variable speed motor 26, with follow-up reduction gearing indicated at 2! is provided for rotating the turret about the lateral or elevational axis to elevate or depress the gun. The base of the bearing pedestals 25 are supported on an inner ring 28. This inner ring 28 is rotatably supported and spaced from an outer ring by means of the upper and lower rollers 29 and 3|. The outer ring 30 is supported by the hull structure of the aircraft.

A reversible variable speed motor 32 is supported on the base structure l9 formed by the inner ring of the turret and carries a pinion 33 at the outer end of its driveshaft. This pinion is in mesh with a ring gear 34 which is secured to the hull supported, outer ring 3!), and pro vides a driving engagement therewith, whereby the turret may be moved about its longitudinal or azimuthal axis to train the gun. I

The lever 35, Fig. 2, control-s the direction an speed of turret rotation and elevation. Movement of this lever fore and aft results in rotation about the elevational axis, while movement of the lever athwartships results in movement of the turret about the azimuthal axis. The rate -of movement of the lever determines the rate of movement of the turret anda diagonal movement of the control lever will result in both an the drawing.

The forward adjustable bead sight 44 is secured to the recoil guide and slide 36 by means of the bracket 31. For the rear sight I have selected the common ring sight 38. This rear ring sight is mounted on the rear gun mount adapter 24. I, have previously used the word sight herein as applying to my device as a whole and also as applying to the specific sighting member such as the bead 40, or the ring sight 38. However, since the sighting members could take some form other than that disclosed, I shall hereinafter, for the sake of clarity, refer to the sighting members as the bead and ring sights, although I do not intend to be so limited.

Referring now to Figs. 4 and 5, which show in enlarged views the structural detail of the bead adjustment. The body 54 of the adjustable bead structure is rotatably supported in a bore 39 of the bracket 31 by means of the laterally extending spindle 52, formed integrally with said body. The bead 4D is secured to a laterally offset arm 4 I. This arm is rotated about the axis 5-5 of the pivotal stem 45 once for each complete revolution of the turret about its azimuthal axis. The pivotal stem 45 is provided with an enlarged collar portion 46 which has an opening 41 drilled therein to provide an adjustable support for the arm, so that the distance between the center of the bead 40 and the axis of the stem 45 may beadjusted for changing air speeds. A set screw 42 is threaded in the collar 46 so as to engage the arm and hold it in its adjusted position. As illustrated, the pivotal stem 45 is reduced in crosssection over .a considerable length at the end opposite the collar. This portion of the shaft is rotatable in the bearing 48 which is held in a cylindrical recess formed in the body portion 50 by means of the set screw 49. The stem 45 is held in the body portion 50 by another set screw 43 which engages the recessed neck 44 of said stem 45. One end of the flexible driveshaft is coupled to the pivotal stem 45, and extends through a flexible housing 56, where its other end is coupled to the worm wheel 52, Fig. 2.

This worm wheel 52 is in mesh with the worm gear 53, which is keyed or otherwise secured to the shaft 54 extending through the hollow trunnion shaft 51. The outer end of this shaft 54 has secured thereto another worm gear 6|. This gear is driven by the shaft 63 through the worm wheel 62. The shaft 63 is driven by the main take-off gear Ell, shaft 64, and worm 65. The teeth of this main take-off gear mesh with the teeth of the ring gear 34 secured to the outer ring 30, so that as the turret is trained about its azimuthal axis the movement of the turret relative to this outer ring 30 and ring gear 34 is transmitted to the pivotal stem 45 and arm 4|.

' The number and size of the gears are selected so that the bead 49 is movedin a direction opposite to the guns movement and through an equal a g e. 59 that, as the turret is trained to one side .aeeaaca of the; .foreiand aft-axis of the aircraft the: arm 4| which carries the bead trails behindthe train of the gun and turretby an equal angle and remains parallel to the. line: of 1 flight, irrespective of the angle of train.

The; entire body 59. of the adjustable bead structure is. rotatablein the bore 39 of the bracket 23:7: so that-as the turret :and gun are-movedin elevation about the trunnionshaft 51, the movement is transmitted to the adjustable bead- The spindle 5-2:.carries at its outer end a beveled ear .66: Thisbeveled gear 66'. is; in mesh with the beveled-gear 51 which is secured toanend ofrthe stub shaft 68.1 This-shaft is rotatable: ina bearing structure similar to that described: in. conangle. of elevationzbut inazreverse direction, so

thatthe'arrnidlof: the. bead 40 will remain parallel tolthefore and aft axis of the aircraft, irrespective of the angle of elevation of the gun.

The::two component-.motions above described are imparted .to-the bead independently: or con- .currentlylwhen the. gun is=moved laterally or: in elevationor insome resultant .of the twodirections of movement; The. distance between the axis 5+5iof the pivotal stem and the plane" of the ring sight. asshown in Fig. 1, is proportional to the muzzle velocityof the bullet, and the distance from theaxis 5-5 to the center of the bead 40. is. (with the same function of" velocity) of a length proportional tothe air speed. The path of the bullet is the resultant of the above componentsof motion and the line of sight should be parallel toor coincide with the path of the bullet for-stationarytargets at the ranges for. which these sight .are' efiective.

The important featureof my invention is that the'arm which carries the bead is kept parallel to the: fore and aft-axis of the plane by-keeping the axis 5- -5= perpendicular to the-roller path ofthe turret, and by trainingthearm about the axis 5- 5 an amount-equal to the angle of train of the. turreton itslroller path but inthe opposite direction; Incase the roller path of the turret is inclined to the fore andaft axis of the plane; it

is only necesary to bend the arm All which carries the bead 40 through an angle equal to the angle of inclinationof the roller path.

In Figs. 7, .8 and 9, Ihave shown diagrammatically the position of the gun relative to the axis of. the aircraft and the position of the arm 4| for various positions of elevation andtrain of the gun. The rear sight is indicated at 38 and the forward bead sight at 4G. The arrow A in eachfigure shows the direction of flight cfithe "aircraft. In each figure the point C' indicates the pnsition of a stationary target, and 0C is the line of sight. The lineBD is in the direction of the axis of .thebore of the gun and would be the normal sight line if the bead 45 were in the axisb-E of the pivotal stem. This line ED also renresentsrthe motion ofthe bullet, due to the explosion of the chargeinzthe chamber of the gun. This wouldbe the true path; of the bulletawere itz not. for I the. motion of the, craft. Therline OC isthecon'ectedsi-ght line as determined by the ring and the bead. The path of the bullet is substantially parallel to this line. In each of these figures the-line CD represents the component of the velocity of the bulletdue to the motion of the aircraft.

It shouldbe noted that in each of the figures the. arm-4i is always. parallel tothe arrow A, indicating thefore and aft axis of the aircraft and the direction of its movement.

Obviously, the sight will function for altitudes higher than illustrated in Fig. 9. In fact, the operator may elevate the turret up to and beyond the vertical as well as below the horizontal. The obstruction to the bead sight, as viewed from Fig. 2 is not so apparent in Figs. 7, Sand 9, and in actual operation the limited position of elevation and of train, wherein the supporting structure of the movable arm would obstruct the gunners view of the bead, does not affect the usefulness of this sight over the greater part of the hemisphere in which the gun may be pointed.

It is, therefore, apparent that I have devised a useful gun sight for a turret mount which properly and accurately corrects for gunners deflection for all angles of elevation and train. My particular gun sight is not, however, limited to use only with a turret mount. In Fig. 6 I have illustrated my gun sight asapplied to a standard flexibly mounted machine gun. The gun l3 and the recoil guide and slide member 35 are secured to its supporting frame 89 by means of the forward and rear

gun mount adapters

23 and 24. This assembly, comprising, the gun, recoil guide and slide, mount adapters and supporting frame, is rotatably mounted on the trunnions 8! between thefraine and yoke 82. The yoke $2 is mounted for movement about a vertical axis of the pedestal support 83 by means of a stem and bearing structure, not shown. The front sight assembly is secured to the recoil guide and slide by means of the bracket 31, while the rear ring sight is mounted directly to the rear gun mount adapter 24.

The front sight assembly is identical to that illustrated in Figs. 4 and 5, and further description is. unnecessary, except that in the mounting here illustratedthe flexible driveshaft 55 in the flexible housing 58 is coupled to the gear 84. This gear is in mesh with the pinion 85, driven by the larger satellite gear 86 mounted on the opposite end of the pinion shaft. This reduction gearing assembly is shown as journaled in the supporting frame 8! which is secured to the yoke 82, so as to be rotatable therewith about the azimuthal axis of the pedestal mount as the gun is moved in train. The larger satellite gear 8% ,meshes with and is adapted to roll around the stationary non-rotatable gear 88, which is fastened to the stationary part of the pedestal supporting structure. As the gun is swung laterally the yoke 82: turns on its azimuthal axis, carrying with it the gear assembly including the satellite gear 86, which is rotated in its bearing surface driving the pinion and the gear 8d. The gear 84 is coupled to an end of the flexible shaft and drives the pivotal stem 45 of the adjustable bead til. This causes the arm 41' carrying the bead 49 toswing about the axis 5--5 of the pivotal stem 45. The size ofthe gears are selected so thatthe arm of the head will swing through an angle equal to the train of the gun relative tothe fore and aft axis of the craft but .inthe reverse direction.

a .Thegear 8.9 issecured: to.-.the. trunnion. 8l-.by

' gunner.

, of the firing plane.

means of the screws 88 so that its axis is in alignment with the axis of the trunnion. The gear 85 is mounted on the frame 86 and as the gun is elevated, the gear Sll'revolves about the stationary gear 39. The gear 99 drives the beveled gear 9% which is coupled to the flexible driveshaft it mounted on the flexible housing H and the beveled gear 61. The beveled gear G meshes with the beveled gear 66 which is secured to the spindle 52 of the body portion 58 of the bead supporting structure, so that as the gun is elevated or depressed, the arm 45 of the bead at and the body bodying my invention, which I claim to be novel,

are correct for any and all angles of elevation and train.

In Figs. 1G, 11 and 12, I have illustrated a modification of my sight adjusting mechanism. In this embodiment the adjusting mechanism is similar to that disclosed in Figs. 4 and 5, except that the vertical axis about which the bead is rotated is laterally offset from the supporting bracket, so that the supporting bracket will not interfere with the line of sight established by said bead and rear sight.

Fig. 10 illustrates the sight as viewed by the In this figure the arrow indicates the direction of flight of the plane and for the arm H 2 of the head E E to take the position illustrated the gun would be trained 90 to the right of the 'fore and aft axis of the aircraft, or abreast the starboard beam. The arm H2 is affixed to and adapted for rotation with the spindle ifili so that the length of the arm may be adjusted by set screw, for example to correspond to the air speed This spindle is supported in the angular bracket ltll in much the same manner that the pivotal stem =35 is supported in the body 58 as shown in Figs. 4 and 5. The flexible driveshaft 55, enclosed in the flexible housmg 553 is coupled to this spindle as at E62.

The angular bracket Hit is supported by the horizontal axis E'E. The pin N33 is keyed to the angular bracket iiii at 5%, and this pin is rotatably supported in a bore 896 formed in the main supporting bracket 105. The worm gear llli is keyed to this pin so as to be rotated by the worm Ht secured to the end of the spindle Hill. The spindle Hill is rotatable in a bearing formed in the main bracket E35 and held in position by means of the two collars M39 and Hi]. This spindle fill is coupled to the flexible shaft l0, as indicated at I 13.

Obviously, the flexible shafts 55 and E6 are each provided with a driving engagement, as illustrated in Figs. 1 to 3, or Fig. 6, so that as the turret or gun is moved in elevation or train relative to the fore and aft axis of the plane the movement is also transmitted to the angular bracket IM, or the spindle mil, so as to maintain the arm 5' parallel to the fore and aft axis of the aircraft and maintain the axis 5'--5' perpensaid roller path,

8 u di'cular to the turret roller path or lateral reference plane.

The circular outline shown in Fig. 11 indicates the path of the center of the bead H5 as the bracket is rotated about its axis 6'-6', when the bead and arm are in a position from that 11- lustrated in Fig. 10. The circular outline shown in Fig. 12 indicates the path of the center of the bead as the arm H2 is rotated about the axis 5-5. The particular advantage of this modification over that disclosed in Figs. 4 and 5 is thus apparent, since as these circular outlines'indicate, the supporting structure will not interfere with the line of sight at any position of the gun relative to the axis of the aircraft.

Other modifications and changes in the number and arrangement of parts may be made by those skilled in the art without departing from the nature of this invention, within the scope of what is hereinafter claimed.

The invention described herein may be manufactured and/or used by or for the Government of the United States of America for governmental purposes without the payment of any royalties thereon or therefor.

I claim:

In combination, a gun turret of the free gun type, a trunnion support therefor about which the turret is movable in elevation, a roller path having a stationary portion upon which the turret is movable in train, a compensating gun sight adapted to be mounted to a machine gun mount ed in s'aidturret, including a sighting element having a laterally ofiset' arm, a rotatable spindle,

means for securing said arm to said rotatable spindle with said sighting element laterally offset flexible shaft secured to said spindle and having a driven engagement with the stationary portion of whereby the movement of the gun in azimuth about said roller path will be transmitted to the spindle and arm, and means for maintaining the axis of rotation of said spindle perpendicular to the plane of the roller path as the turret is elevated about the axis of the trunnions, said last namedmeans comprising a rotatable support for the assembly comprising said spindle, arm, and sighting element, whereby the assembly may be rotated about an axis normal to the axis of said spindle, and means for rotating said support and said assembly about said axis comprising a flexible shaft having a driving engagement with said trunnions whereby the assembly will be rotated as the turret is moved in elevation.

DANIEL V. GALLERY, JR.

REFERENCES orrnl) The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,211,400 Burns Jan. 9, 1917 1,650,628 Inglis -1 Nov. 29, 1927 2,4411%! Haubroe May 11, 1948 FOREIGN PATENTS Number Country Date 125,146 Great Britain Apr. 17, 1917 215,68? Switzerland July 15, 1941 607,188 Germany Dec. 19, 1934 I 781392 France Feb. 25, 1935