Patent GB-601209-A (GB)
Title: Apparatus for use in teaching shooting against moving targets by means of photo-electric apparatus
IPC: F41G3/26
Filed: 1942-11-27
Abstract: 601,209. Gunnery training apparatus. VITARAMA CORPORATION. Nov. 27, 1942, No. 16919. Convention date, Oct. 17, 1941. [Class 119] Apparatus for use in teaching shooting at inoving targets comprises a dummy gun adapted to be aimed at a target image (such as that of an aeroplane) projected on to a screen, photo-electrically operated means for indicating a hit or miss when the dummy gun has been aimed and " fired," and control means bearing indicia related to factors affecting the registration upon a relatively moving target of a projectile fired from a gun, the operation of the indicating device being determined and controlled by the aiming movements of the dummy gun and the co-ordinated movement of the control means. Three sets of apparatus diagrammatically shown in Figs. 1-3 may be combined into a single system, the components of which may be used together in various ways as required. (1) Fig. 1 shows an embodiment of apparatus in accordance with the invention, comprising a dummy gun 25 associated with a projector 20 which throws upon a screen 21 pictures of a moving aeroplane. The projector is driven by a motor M which also drives mechanism in apparatus 49 which moves a band 36 in synchronism with the picture film. Indications 55 in the form of transparent apertures are provided, one on each frame of the band, in predetermined positions, and a light beam projecting system 57 ... 60 is so arranged that the beam, if properly directed, can pass through an aperture 55 on to a photo-electric cell 56. The dummy gun 25 and the support 35 for the optical system 57 &c. are each movable about horizontal and vertical axes, the gun and the support 35 being connected together, e.g. by cords 39, 40, in such a manner that when the gun (which is provided with sights 30) is moved by the gunner in aiming at the image target, the support 35 follows these movements. Each of the indications 55, which may be formed as crosses, is located in a position on a frame of the band 36 which takes account of such factors as the position of the target image which is being projected from the corresponding frame on the picture film, its distance from the gun and the time of light from gun to target of an imaginary projectile. Thus, if the gun is correctly aimed at a given instant, at a point appropriately in advance of the target image when it is moving across the screen, the beam from the lamp 57 will pass through the aperture 55 which at that moment is stationary in the gate of the apparatus 49. Then if at the same time a trigger 31 on the gun is pulled, a circuit, completed through the effect of the light on 'the cell 56; is closed through a control box 66 and a bell 65. Ringing of the bell indicates that the gun is properly aimed for a hit on the target. Instead of a bell, means for giving a visual indication may be used. A rotary switch 67, 68, or an obturating shutter, ensures that the indication is not given when the band 36 is moving. A lamp and lens system may be provided on the gun instead of or in addition to the sights, so that the aim may be indicated by a light spot 95 on the screen. The instructor may switch on the lamp at any time, to check the trainee's aim. (2) In Fig. 2, apparatus is shown which has the purpose of throwing on to the screen, at a predetermined time after the trigger has been pulled, a light spot which gives a direct indication whether a hit has been made or not. Means are provided for delaying the projection of the spot after the " firing," for a time equivalent to the time a projectile would take to reach the target, so that if the aim is correct, when the light spot appears it will coincide with the target image. By using a phosphorescent screen, a succession of bursts may be transiently recorded on the screen as luminous spots which fade progressively. " Hit spot " markings may be provided on the picture film itself, but the use of a separate indicia-carrier is preferred. The apparatus shown comprises, in addition to a dummy gun 25 and projector 20, means coupled with the projector for feeding a control band 36 past a scanning plate 121 in which is an aperture 122. The band 36 has light-transmitting indications 120 arranged at distances from a margin of the band corresponding to the times of flight of the projectile. The scanner 121 is adapted to move at a uniform speed across the band, being started automatically when the trigger 31 is pulled, and when the apertures 122, 120 coincide light passes to a photo-electric cell 56<SP>1</SP>. This initiates the action of a control box 66<SP>1</SP>, producing the effect, inter alia, of energizing a lamp 96 on the gun, to project the indicating spot 95 on to the screen. The gun is locked in the aimed position when the trigger is pulled. For this purpose, brake bands 100, 110 are associated with the shafts 26, 28 on which the gun is mounted, the brakes being operable by spring-controlled toggles 101, 111 adapted to be actuated by solenoids 102, 112. When the trigger is pulled, circuits are closed which energize the solenoids that cause the brakes to be applied, and a locking circuit, including leads 115 to the control box 66<SP>1</SP> is also closed, a timing device in the control box temporarily holding this circuit closed to keep the brakes on and the spot lamp in action for a predetermined time. Simultaneously with the application of the brakes, a third solenoid 131 is energized and clutches a drum 126 to a constant-speed-motor M<SP>1</SP>. The drum is connected by a cord 125 to the scanner 121, and when it is rotated, moves the scanner, against the action of a spring 124, across the band 36. Limit switches 135, 136 coacting with the scanner, assist in controlling the operative circuits. (3) Fig. 3 shows a more elaborate form of dummy gun than that shown in Fig. 1, together with control apparatus, additional to that of Fig. 1, which is provided for the purpose of taking into account other factors which may influence aim at the target, such as windage, gravity drop of the projectile and the advancing or receding of the target. In this modification, the gun 25 carries in it, movable relatively thereto on vertical and horizontal shafts 28<SP>11</SP>, 26<SP>11</SP>, a support 142<SP>11</SP> for a light spot projector. Each shaft has a spring-influenced arm 28A or 26A, under the control of solenoids 28B or 26C which are connected to a control box 66<SP>11</SP> to which a trigger switch 31, 32 is also connected. The band 36 is provided with series of light apertures 155 which are arranged in such manner as is necessary to determine what movements are to be given to the spot projector relatively to the gun, the apertures 155 being adapted to register with openings 156 in a fixed plate 157. Thus, varying amounts of light fall on photo-electric cells 56<SP>11</SP> in prearranged sequences, and by the effects so produced on the circuits associated with the solenoids 28B, 26C, the requisite movements of the shafts 28<SP>11</SP>, 26<SP>11</SP> of the spot-light projector support are brought about. Figs. 11 and 12 (not shown) illustrate the construction of a dummy gun and spot-light projector somewhat similar to and for the same purpose as that shown in Fig. 3. In this modification, stepby-step movements about vertical and horizontal axes are given to the spot-projector by pawl-and-ratchet mechanism operated by solenoids, to which impulses are imparted by means of a bank of photo-electric cells, to each of which light is transmitted as required through apertures in the control band. In this case, components of the spot-projector support which have horizontal and vertical movements with respect to the gun can be locked relatively thereto by brakes. Details of arrangements are also shown for guiding the cables connecting the gun to the support for the optical system such as that shown at 57 . . . 60 in Fig. 1. Further modifications, details and accessories. -In a control band for use in apparatus such as that shown in Fig. 1, the apertures 55 may be of different sizes, so that if, for example, the projected image shows the target approaching, larger apertures may be used. The apertures may be made photographically, and a device for this purpose (Fig. 14, not shown) comprising a collet chuck forming a variable cross-shaped aperture, is described. Apertures of various geometrical designs may be used (Fig. 8, not shown). Both the aim-indicating apertures 55 and the " delayed spot " apertures 120 may be provided on one control band 36, as well as the additional apertures such as those shown at 155, Fig. 3, if required. Fig. 10 shows apparatus for using a combination control band 36 having the two sets of apertures 55, 120, the purpose of this apparatus being to combine the functions of the systems shown in Figs. 1 and 2. Associated with each set of apertures is a lamp and a photo-electric cell, a scanner 121 being provided, as well as a light aperture 60 for the aimregistering apertures 55. The cross-shaped aperture 60 is provided by an expansible collet 87, mounted on a horizontal slide 35, itself slidable vertically on guides 90. The movements of the part 87 are co-ordinated with the aiming movements of the gun 25 by means of the cords and linkage mechanism shown. In this modification, an annular rotating shutter 92 is used instead of the switch 67, 68 shown in Fig. 1, and, for the same purpose. Various methods of forming the apertures in the control band at the appropriate positions thereon are described, and a device for providing such apertures by punching is described with reference to Fig. 17 (not shown). A number of dummy guns and projectors may be used in conjunction with a part-spherical screen, each gun being operable independently of the others and associated with its own photo-electric electric indicating apparatus. Appropriate sound effects (which may be obtained by means of sound films recorded whilst the kinematograph pictures