US3059338A - Sighting device for firing at a moving target - Google Patents

Description

Oct. 23, 1962 G. E. COEYTAUX SIGHTING DEVICE FOR FIRING AT A MOVING TARGET Filed Oct. 22, 1956 6 Sheets-Sheet l FIGJ INVENTOR G. E. COEYTAUX Oct. 23, 1962 G. E. COEYTAUX 3,059,338

SIGHTING DEVICE FOR FIRING AT A MOVING TARGET Filed Oct. 22, 1956 6 Sheets-Sheet 2 m I Q $1 89, \1'

w i N N 9% m/ Q l w w k) N L m 2 INVENTOR a Georges E Coey/aaa by Almrneys' SIGHTING DEVICE FOR FIRING AT A MOVING TARGET Filed Oct. 22, 1956 Oct. 23, 1962 G. E. COEYTAUX 6 Sheets-Sheet 3 FIG 4 INVENTOR, Georges E Coeyfaux by mm, m 14 MA Allarndys SIGHTING DEVICE FOR FIRING AT A MOVING TARGET Filed 001.. 22, 1956 Oct. 23, 1962 G. E. COEYTAUX 6 Sheets-Sheet. 4

INVENTOI? GeoigesE Coeylaux by Mum, WM

Attorneys Oct. 23, 1962 G. E. COEYTAUX 3,0

SIGHTING DEVICE FOR FIRING AT A MOVING TARGET Filed Oct. 22, 1956 I 6 Sheets-Sheet 5 //V VE N TOR,

Georges E. Caeyfaux Oct. 23, 1962 cs. E. COEYTAUX 3,

SIGHTING DEVICE FOR FIRING AT A MOVING TARGET Filed Oct. 22, 1956 e Sheets-Sheet s GEORGES E. COEYTA W I N VENTUR 5v MM, Mil/M ,4 TTORNE v5 United rates atent @fitice Patented Got. 23, 1962 3,059,338 SIGHI'ING DEVICE FOR FWG AT A MQVENG TARGET Georges E. Coeytaux, 25 his Rue du Qhateau, Neuiliy-sur-Seine, France Filed Oct. 22, 1956, Ser. No. 617,604 Claims priority, application France Oct. 24, 1955 2 Claims. (6i. 33-49);

The present invention relates to a sighting device that is intended as equipment for artillery material, e.g., field artillery, self-propelled guns, guns with armored gear or recoilless guns whether or not on self-propelled guncarriages, especially for firing on moving terrestrial targets. It is known that the function of such sighting instruments is to work out the correction or by which it is necessary to displace the line of fire of the firearm ahead of the target in order to take into account the displacement of the target during the time of travel of the projectile.

The sighting device of the invention uses the only data measurable from the position of firing, that is to say the tangential angular speed of the target and its distance. The distance is measured either with an optical telemeter of a known type or with electromagnetic means of a known type or is, more simply, estimated by the gunlayer. The angular speed is, according to the invention, measured directly by the sighting device by the method hereinafter described. The lead angle correction on is equal to the product of the measured angular speed and the time of travel T of the projectile. The time of travel T of the projectile is a known linear or non-linear function of the distance. As the latter is supposed to be known, the time T is also known and it constitutes a datum in the operation of the sighting device.

According to the invention, the sighting device comprises a telescope and means for causing to appear, in the focal field of said telescope two spider-lines at right angles to each other, one horizontal and the other vertical, the positions of which are controlled by a first knob for feeding time T and by a second knob the rotation of which, when operated as set forth below, is consequently proportional to the product a of T by the angular speed a: of the target, and is accordingly provided with an a scale. There also appears a movable grating on which there is impressed, by means of the two knobs conjointly, a speed of displacement which is equal to the angular speed of the target. It should be noted that, if T is a datum of the operation of the sighting device, a is an unknown variable until shown at knob 6, which indicates precisely the value desired for the correction when there has been obtained, by means of the two knobs conjointly, the equality of the speed of displacement of the grating and the angular speed of the target.

The invention will now be described in detail with reference to the accompanying drawings, of which FIG. 1 represents the focal field of the telescope;

FIG. 2 represents diagrammatically a sighting device according to the invention;

FIG. 3 is a longitudinal, vertical sectional view of such a sighting device;

FIG. 4 is a transverse vertical section on line 4-4 of FIG. 3;

FIG. 5 is a horizontal section on line 55 of FIG. 3;

FIG. 6 is a vertical section on line 6-6 of FIG. 4; and

FIG. 7 is a perspective schematic view of the apparatus of FIGS. 3-6.

The gun-layer sees in his telescope, which is rigidly connected to the firearm, the focal field 11 shown in FIG. 1. He sees appear in the light, on the image of the landscape in which the target 2 is located, a luminous grating 3 of equidistant vertical lines. This grating may be driven, with a certain lateral speed, either towards the right or towards the left. This speed a) is, as has been seen, a function of two variables T and u. The gun-layer, after having brought the target 2 approximately into the field l of the telescope (by rotating his turret or his firearm with the aid of the sighting wheel), equalizes the speed of the target with the speed of the grating by regulating the speed of the grating with the aid of an operating knob 6 called the tachymetry knob the amount of rotation of which when equalization is achieved being proportional to or, after having also regulated this speed proportionately to l/ T by rotating a knob 7, called the superelevation knob, proportionately to the superelevation H, as will be explained later H being supposed to be a linear function oi the time of travel T.

The tachymetry knob 5, which modulates the speed of the grating proportionately to 0:, also displaces horizontally, in the focal plane of the telescope, a vertical spiderline 4, giving exactly the correction on in relation to a reference line 8 and vertical numerical scales 4a. and 4b; the second or superelevation knob 7, which modulates the speed of the grating proportionately to 1/ T, displaces a horizontal spider-line 5 vertically in the focal plane of the telescope, giving exactly the superelevation H; the proper amount of rotation of knob 7 is achieved by adjusting the position of spider-line '5 relative to scales 4a, 4b in accordance with the numerical value corresponding to the estimated, or known from other means, distance of the target. When the gun-layer has obtained equality of the speeds of the movable grating and of the target, the intersection a of the vertical spider-line and the horizontal spider-line in the focal plane gives him exactly the point of the focal plane of his telescope with which he is to aim at the target. He then displaces his firearm and the sighting device which is fixed to the firearm, with the sighting wheels in a direction to bring the target 2 on to the crossing 9 of the two spider-lines and he then fires, or else he waits for the movable target 2, the image of which is displaced along the horizontal superelevation spiderline 5 to cut the vertical spider-line 4 of allowance for lateral deviation.

A non-restrictive example of embodiment of this sighting device is given in FIG. 2.

A direct-current electric motor 10, which gives a very regular movement, drives a drum 16 on which is brightly engraved, on a dark background, a helix 17, the image of which is projected optically into the focal plane of the telescope through the intermediary of a separating filter. This optical projection is effected by any known means (collimation), so that the image of this helix appears in the focal plane of the telescope as equidistant vertical lines. If required, the motor may be replaced by a mechanical motor with a regulator or a clockwork movement.

This motor produces the movement of the grating not directly but through the intermediary of two speed changers which, by way of non-restrictive example, may be mechanical changers with rollers or with a ball-race. These changers are of the type shown on page 25 of Computing Mechanisms and Linkages, Radiation Laboratory Series, vol. 27, McGraw-Hill Book Company Inc., 1948. These two changers are mounted in series, one following the other as shown in FIG. 2. The first changer comprises the cylinder 11, which is driven directly by the motor '10, the ball-race 12 and the disc 13 and it is arranged in such a manner that the movement of the ballrace is connected with the movement of the knob 7 which also effects the movement of the horizontal spider-line 5 of the telescope, giving the superelevation. The second changer comprises the disc 13, the ball-race 14 and the cylinder 15 driving the drum 16 directly, and it is arranged in such a manner that the movement of the ballrace is connected linearly with the vertical spider-line 4 giving the lead-angle correction, these two movements being produced by the knob 6. It is seen that, due to the fact that the distance of ball- races 12 and 14 to the axis of the disc 13 are respectively proportional to T and the speed of the engraved drum 16, that is to say of the spider-lines seen clearly in the telescope, is modulated in accordance with the ratio of the two variables a and T, thus giving the formula which is the law of target-correction.

FIGS. 3, 4, 5 and 6 give a practical example of such a telescope which has been constructed by the applicant. The driving motor is represented at 10 (FIG. 3) and the tachymetry knob and the superelevation knob are represented at 6 and 7 respectively. The motor It) drives the cylinder 11 by means of the tangent screw 18 and the pinion 19.

The knob 7 drives, through the intermediary of the kinematic chain comprising the pair of pinions 20, the shaft 21, the pair of pinions 22, the oblique shaft 23 (FIG. 5) and the pair of pinions 24, the screw-threaded rod 25 on which slides a nut which carries the ball-race 12. In addition, this knob, through the intermediary of the pair of pinions 26 (FIG. 3) and the shaft 27 having a threaded end 27a threaded into block 33a on which glass plate 33 is mounted causes a displacement in the vertical direction of the glass plate 33 which is situated in the focal plane of the telescope and bears the horizontal spider line 5.

The knob 6 drives, through the intermediary of the oblique shaft 30 (FIG. 5) and pinions 31a in the drawings, the screw-threaded rod 31 similar to the screwthreaded rod 25 and on which slides a nut which carries the ball-race 14. In addition, this knob effects, through the cross shaft 32, a pair of pinions, not shown, and the shaft 28, which has a threaded end 28athreaded into block 29a on which plate 25 is mounted, the displacement, in the horizontal direction, of the glass plate 29 which is situated in the focal plane of the telescope and bears the vertical spider-line 4.

The cylinder drives, through the intermediary of a kinematic chain shown in FIG. 4, the screw-threaded rod 34 which eifects the lateral movement, from right to left or from left to right, in the plane of FIG. 4, of the grating 35. The driving arrangement for the grating is better shown in FIG. 6. This grating 35 is supported by a chassis 55 guided by the balls 56 rolling in the grooves 59 (also shown in FIG. 4) and also guided by the rod 57. The chassis 55 carries an extension 58 which forms a nut engaged with the screw 34. The rotation of the screw 34 brings about a displacement of the grating 35 in a direction perpendicular to the plane of FIG. 6. In this embodiment, the grating 35 is a flat grating mounted on a carriage instead of being a helix carried by a cylinder as in the case of FIG. 2. This grating is projected into the focal plane of the telescope by the collimator 36 and the perpendicular minors 37 and 38. 39 and 40 (FIG. 4) are respectively the objective and the eyepiece of the telescope.

In this embodiment the grating comes to a stop at the end of a certain time. If this occurs before the gun-layer has adjusted the speed by acting upon the knob 6, the grating may be disconnected and led back to its mean position. This is done by rotation of the shaft 50 (FIG. 4) which carries for this purpose a manually engageable member, only the cross section 50a of which is shown' and which is held on shaft 50 by a pin (unnumbered). The rotation of the shaft 50 rotates the plate 51, which is mounted on shaft 50, which in turn rotates, by means of the stud 52, which stud is mounted on plate 51, the

pivotal mounting 54 upon which is rotatably mounted the screw 34. The mounting 54 then turns with the shaft 60, journaled in fixed supports 690, 6%, and the screw 34 is no longer engaged with the extension 58 (FIG. 6) of the chassis 55. The chassis and the grating that it carries are thus released for return to the mean position.

The system of speed-modulation by mechanical changers in cascade is given by way of example. It is quite obvious that the invention is equally applicable to a system of speed-modulation which carries out the law purely electrically or electronically.

The advantages of the invention as compared with all the proposed systems of tachymetric telescopes giving corrections of aim are the following:

(1) Absolute stability of the determination of the correction.

In fact, the grating 3 which is used for the tachymetry is independent of the spider-line used for the sighting; this obviates all the effects of instability which are observed in tachymetric systems with single spider-lines, in which the spider-line which is used for the sighting is that which is also used for the tachymetry.

(2) Robustness and ease of operation.

In fact, the kinematic chain, which connects the m tOr to the rotating cylinder 16, requires substantially no torque and needs only to be speed regulated. The displacements of the spider- lines 5 and 4, which are used for sighting in elevation and in direction, are carried out by the hand of the gun-layer, that is to say with all the torque that is desired. The kinematic speed chain can therefore be produced with a very accurate mechanism.

The tachymetry can be carried out when the image of the target is located at any position in the focal plane of the telescope because the grating covers the whole of the focal field 1 and the target image 2 is still located between two lines of the grating.

(3) The correction in direction remains marked in the telescope; this is a great advantage for any repetition of the firing.

What I claim is: 1. A gun sighting device intended to be fitted on a firearm and adapted to deliver automatically the lead correction 0: corresponding to the unknown transverse speed of a target the distance of which is known, comprising a telescope with a first and a second plate in its focal field, said first plate having a horizontal spider line thereon movable vertically in said focal plane and said second plate having a vertical spider line thereon movable horizontally in said focal plane, a vertical line grating movable horizontally, optical means forming the image of said grating in the focal plane of said telescope, a first and second knob for driving said first and second plate respectively and for controlling the rate of movement of said grating, a first plate driving means connected between said first knob and said first plate for driving said horizontal spider line, a second plate driving means connected between said second knob and said Second plate for driving said vertical spider line, said first knob being adapted to introduce the time of travel T of a bullet fired by the gun at the target as a function of the known distance by drivingsaid horizontal spider line, said second knob being adapted to introduce the unknown lead correction by driving said vertical spider line, and grating speed control means controlled by said knobs and connected to said grating for obtaining a speed of said grating proportional to a/T, whereby the adjustment of said second knob equalizing the apparent speed of the grating to the apparent speed of the target as seen through the telescope maintained steady introduces the correct lead correction at.

2. A sighting device as claimed in claim 1, wherein said grating speed control means comprise a first speedchanger with a drum, a plate and a ball-race interposed 5 between the plate and the drum, the drum rotating at a References Cited in the file of this patent constant speed and the position of the ball-race in rela- UNITED STATES PATENTS tion to the center of the plate being proportional to the time of travel T of the projectile, and a second speefigzggg changer with a drum, a hall-race, and the plate of the 5 2526677 Mackta 1950 first speed-changer, the position of the last mention d u ball-race in relation to the center of the plate being pro- FOREIGN PATENTS portional to the correction on and the last mentioned 579,848 Great Britain Aug. 19, 1946 drum effecting the displacement of the grating. 63 8,828 Great Britain June 14, 1950

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