US2382777A - Gunnery practice device - Google Patents

Description

Patented Aug. 14, 1945 GUNNERY PRACTICE. DEVICE Tord Olof Richard Dahlberg, Nockeby, and Karl Matts Vigborg', Stockholm, Sweden, assignors to Kooperativa Forbundet Forening U. P. A.,

Stockholm, Sweden Application February 16, 1943, Serial No. 476,042 In Sweden October-28, 1940 3 Claims.

The present invention relates to a gunnery practice device, and more particularly, to a device for practicing the control of anti-aircraft guns of the type in which the altiudinal and the azimuthal adjustments are effected by different directors.

One object of the present invention is to provide a gunnery practice device of the type described which can be mounted on the barrel of a gun and which includes model targets adjustable relative to the gun sights in altitudinal and in azimuthal direction.

Another object of, the invention is to devise a practice mechanism in which each of the two directors operating the altitudinal and the azimuthal adjusters, respectively, observes a difierent model target, and two model targets being, however, controlled in unison by the instructors.

A still further object of the invention is to provide a gunnery practice device mounted on a gun barrel and including model targets which can be displaced relative to the gun barrel and sights by the instructor in any desired altitudinal or azimuthal direction, without any change in the position of the barrel, said same targets being displaced in the opposite directions, so as to reduce the displacements effected by the instructor to zero, upon operation of the gun barrel directing mechanism by the directors in a way to follow the apparent movements of the target.

These and other objects which will appear more clearly as the specification proceeds are accomplished by the arrangement and combination of parts set forth in the following detailed description, defined in the appended claims and illustratively exemplified in the single figure of the accompanying drawing which is a diagrammatic perspective view of one embodiment of the invention.

The drawing shows a gunnery practice device applied to an anti-aircraft gun provided with a central seat for an instructor and two lateral seats S and H to be occupied by two trainees or directors. Two diopter or telescopic gun sights, shown diagrammatically in the drawing are mounted. on the gun for the directors operating the direction handle So to effect azimuthal adjustments of the gun and the elevation handle Hz; to effect altitudinal adjustments of the gun, respectively. The practice device comprises two miniature targets in the form of model aeroplanes Sm and Hm which are mounted in front of the sights Ss and H5, respectively, by means of short vertical rods I formed at the ends of an elongated target support 3 extending at substantially right angles to the optical axes of said sights so that each director when sitting in his seat (S, H) can observe the corresponding target figure (Sm. Hm) by leaning over and looking through his gun sight (Ss, Hs). The elongated support 3 is, at its center, rigidly connected with the forward end of a tube 2.

The tube 2 is connected with the barrel E of the gun by a suitable fitting 4, and it is movable relative to said barrel and fitting on a pivot 5 in two planes which are at right angles to one another. Within the tube 2 there is a nut 6 traversed by a screw .8 which is rotatably mounted in a yoke l. 27 is a counterweight displaceable in the tube 2. The screw 8 carries a bevel gear wheel 9 cooperating with a bevel gear wheel H which is driven from a shaft H]. To the yoke 7 is fixed a sleeve l2 with internal screw thread engaged by a screw l3. To screw 53 is fixed a bevel gear wheel 14 which is in driving mesh with a bevel gear wheel [6 fixed to a shaft IS. 'The gear wheels I4 and It, the screw l3 and the shaft l5 are mounted in a frame I! fixed to the barrel E, while the gear wheels 9 and H are mounted in bearings formed in the yoke l. The shaft Ill and also the shaft l5 may be flexible shafts, if desired. Suitable guide members which form a part of the frame ll but which have been omitted from the drawing for the sake of clarity are provided to guide the yoke I vertically.

As shown each of the shafts Ill, 15 extends into a differential gear casing l8 and has a differential bevel gear wheel l9 fixed to its end inside said casing. Other bevel wheels 20 are fixed to the casings l8 and are in mesh with gear wheels 2| secured to shafts 22 which, at the turning of the handle Sc and Ho respectively, are rotated by gears 23 connected with said handles. By means of two handles 02) the instructor, when seated in his seat 0, may via the differential gears, set the wheels l9, and the shafts l0 and 55 respectively, in rotation. The screws 8 and 13 are actuated during this rotation, and. the tube 2 will swing in the vertical as well as in the horizontal direction i. e. the target figures Sm and Hm will move. Consequently, the directors operating the gun aiming mechanism must now catch the target figures by turning the handles S2) and Ho so as to retain the figures on the respective lines of sight. This result is accomplished if the motions of the handles So and H12 are so dimensioned with respect to the motions of the handles 01) that the resulting displacement of the tube 2 with respect to the gun barrel E is zero. The instructor can easily ascertain this by switching on a lamp L fixed to the barrel E by a bracket 24, because if the setting is correct, the pencil of rays of said lamp will penetrate a sight plate V located between a movable indicator formed by a third target figure Om mounted centrally on the support 3 and the lamp L and catch the figure Om. The lamp L being concealed from the directors, the ignition of the lamp introduces an element of surprise. To guide the tube 2 while the directing motions are carried out a yoke-formed part 25 is connected with the fitting 4, the bent outer portions of said part insuring that the tube does not turn around its longitudinal axis by engaging the ends of a transverse member 26 connected with the tube 2.

Thus, the above described system of motion makes it possible to impart to the difierent target figures motions relatively to the barrel E in two planes which are at right angles to one another, and the combination of motions within these two different planes is sufficient to impart universal motions to the target figures, said motions corresponding to the motions of real targets. It will be seen that, whatever motion may be imparted to the model targets from the seting means 01) operated by the instructor, a proper cooperation of the two independent control mechanisms Hz; and So by the directors will bring each model target into and hold it in the field of the corresponding sight while the gun barrel carries out the movements induced by the operation of the handles Hz; and S2). Both model targets Hm and Sm which are fixed to the common support 3 and always move in unison, represent only one single actual target. At the distance of an actual target, the optical axes of the two telescopic sights merge, so that a target which is in the field of one sight appears also in the field of the other sight. This, however, is not true at the short distance from the sights at which the model targets are arranged, according to the present invention, and it is, therefore, necessary to represent the single actual target in front of each sight by a separate small scale model. The instructor by operating the handles 01; imparts to both models Hm and Sm exactly the same altitudinal and azimuthal displacements relative to the corresponding sights. The directors must cooperate to compensate for these two displacements so as to hold each model inthe field of associated sight, exactly as in aiming at an actual target the director effecting the altiudinal adjustment must cooperate with the director effecting he azimuthal adjustment to hold the single actual target in the field of both telescopic sights. By providing the shafts 22 with friction couplings, fOr example in the way shown in the drawing, where the gear wheel 23 is rotatably mounted on its shaft 22, and i pressed by a spring against a disc 28 fixed to the shaft 22, it is possible to swing the barrel quickly to any position determined by the instructor and when the position in question has been reached the instructor grasps the handles 02) and then the directors will have to catch and follow the target figures. The drill can then be quickly interrupted and quite on opposite setting of the barrel can be ordered, and the catching and following of the target figures can be resumed.

The device may also be applied with advantage in a central fire control instrument with the same arrangement except that the shafts 22 will be in driving connection with the members adjusting the two forward sights, said members thus corresponding to the handles So and Ho in the drawing.

Several embodiments are, of course, possible within the scope of the invention. Particularly the members adjusting the rod 2 may be varied in a great many ways without departing from the basic idea of the invention.

Having now described our invention, what we claim as new and desire to secure by Letters Patent is:

1. A gunnery practice device for application to an aiming mechanism including an adjustable member adapted to be trained upon a target and carrying two parallel telescopic sights for use in the altitudinal and in the azimuthal adjustments, respectively, of said member, said device comprising a single elongated target support mounted on said adjustable member in front of said two sights at substantially right angles to their optical axes, two model targets mounted on said support at a fixed distance from each other equal to that between the optical axes of said sights, setting means for imparting to said target support selected altitudinal and azimuthal movements relative to said sights, a first independent control mechanism arranged for operation by a director looking through one of said sights to impart to said target support selected altitudinal movements relative to said sights which may serve to compensate for the altitudinal components of the movements effected by said setting means, and a second independent control mechanism arranged for operation by a second director looking through said second sight to impart to said target support selected azimuthal movements relative to said sights which may serve to compensate for the azimuthal components of the movements effected by said setting means, whereby, upon a proper cooperation of both said control mechanisms, each of said model targets may be brought into and held in the field of the corresponding sight.

2. A gunnery practice device, as claimed in claim 1, in which'each of said control mechanisms comprises a differential gear and means for actuating one member of said differential gear, and said setting means includes means for transmitting torque to other members of said two difierential gears.

3. A gunnery practice device, as claimed in claim 1, including a movable indicator mounted on said target support in a fixed spatial relation to said model targets, and a fixed indicator mounted on said adjustable member in the vicinity of said target support and in a corresponding spatial relation to the optical axes of said sights, whereby an axial coincidence of said movable indicator with said fixed indicator indicates a correct adjustment of both said control mechanisms.

TORD OLOF RICHARD DAHLBERG. KARL MA'I'IS VIGBORG.

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