US2409914A - System and apparatus for gunfire control - Google Patents

Description

F. E. VALENTINE ETAL. 2,409,914

SYSTEM AND APPARATUS FOR GUNFIRE CONTROL Filed March 20, 1935 6 Sheets-Sheet 1 Oct. 22, 1946.

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SYSTEM AND APPARATUS FOR GUNFIRE CONTROL Filed March 20, 1935 6 Sheets-Sheet 2 Frank E. ValeTrEine, Walter F? Skillin,

Their AtEoT M Oct. 1946- F. E. VALENTINE ETAL, 2,409,914

SYSTEM AND APPARATUS FOR GUNFIRE CONTROL Filed March 20, 1935 6 Sheets-Sheet 3 Inventors: Frank E. Valera-tine, Walter T? Skill'm,

by #44 8. BMW

Their Attorneg.

Oct. 22, 1946. F. E. VALENTINE EIAL 2,409,914

SYSTEM AND APPARATUSFOR GUNFIRE CONTROL Filed March 20, 1935 6 Sheets-Sheet 4 \nventors: v Frank E. Valentine, Walter F Skilhn,

Then" Attorney.

m w HUM m M E m V m w GEUMKHK'IUAL Hh) l Huwwn Oct. 22, 1946. F. E. VALENTINE EIAL 2,409,914

SYSTEM AND APPARATUS FOR GUNFIRE CONTROL Filed March 20, 1935 6 Sheets-Sheet 6 inventors: nk E..Valewt|ne Walter F Skillin,

H The? Attorney Patented Oct. 22, 1946 1d tal tail MUM!" SYSTEM AND APPARATUS FOR GUNFIRE CONTROL Frank E. Valentine and Walter F. Skillin, Schenectady, N. Y., assignors to General Electric Company, a corporation of New York Application March 20, 1935, Serial No. 12,006

17 Claims.

This invention relates to the control of guns and the like, more particularly to the control of guns mounted on swaying foundations, such as on a rollin ship, and it has for its object the provision of an improved system and apparatus for directing guns whereby corrections are applied to the guns compensating for the inclination of the trunnions of the guns due to the roll of the ship, or other foundation on which the guns are mounted.

In the directing of guns, the calculated adjustments of range to be applied to the gun in elevation and of deflection to be applied to the gun in train are based on the assumption that the adjustments will be applied to the gun in true vertical and horizontal planes; that is, it is assumed that the trunnions of the gun about which the gun is elevated lie in a true horizontal plane, and that they are mounted so that the gun is adjusted in train on a true vertical axis. The gun, however, is mounted with its trunnions parallel with the deck of the ship on which it is carried, and thus, it is adjustable in elevation in a plane which is perpendicular to the deck and in train in a plane which is parallel to the deck. Therefore, it is only when the ship is on .even keel that the gun is adjusted on train and elevation axes which are truly vertical and horizontal. Consequently, it is only when the ship is on even keel that the calculated corrections for range and deflection are properly applied to the gun.

This invention contemplates the provision of an improved system and apparatus whereby the roll or inclination of the ship or other support on which the gun is mounted about the line of sight of a target is continuously calculated and introduced as a correction so that the calculated elevation and train adjustments, based on the assumption that the gun is to be adjusted in true vertical and horizontal planes, are continuously modified in accordance with the inclination of the ship so as to direct the adjustment of the gun to cause it to assume continuously the position in space that it would occupy when adjusted with reference to the true vertical and horizontal.

In accordance with this invention, suitable gun directing apparatus is provided comprising means for generating the range and deflection corrections, calculated on the assumption that they will be applied to the gun with the ship on even keel, together with means for regenerating these values continuously in accordance with the inclination of the ship's deck when the ship rolls about the line of sight, as corrections which can be applied directly to the gun in elevation and train to cause it to assume the proper position in space with reference to the true vertical and horizontal.

More specifically, the gun directing apparatus in accordance with this invention comprises a mimic gun which is mounted in a gimbal system responding to the train and elevation axes of the main gun perpendicular to and parallel with the deck of the ship. The gimbal system further provides for inclination of these axes with reference to the true vertical and horizontal in accordance with the inclination of the deck so as to cause the mimic gun to move in space with reference to the true vertical and horizontal to assume the position that the main gun would assume if permitted to move with the ship-uncompensated for its roll-to thereby generate the corrections that should be applied to the calculated values of range and deflection to be applied to the main gun to hold it in its correct position in space.

For a more complete understanding of this invention, reference should be had to the accompanyin drawings, in which Fig. 1 is a diagrammatic representation of a system and apparatus for controlling guns and the like arranged in accordance with this invention; Fig. 2 is an elevation of a sighting device or director used in the system of Fig. 1 and arranged in accordance with this invention; Fig. 3 is a plan view of the director shown in Fig. 2; Fig. 4 is a diagrammatic view showing a certain means for transmitting motion used in the system of Fig. 1; Fig. 5 is an enlarged perspective view illustrating a portion of the mechanism used in the director of Figs. 3 and 4; Figs. 6, 7, 8, 9, 10, and 11 are diagrammatic views illustrating the principle of operation of the mechanism shown in Fig. 5; Fig. 12 is a perspective view illustrating a modified form of the mechanism shown in Fig. 5; and Fig. 13 is a perspective view of a further modified form of the mechanism shown in Fig. 5.

As pointed out previously, in directing guns on a target, the range correction, which will be called sight angle hereinafter, is a function of the range of the target, as calculated, and is an angular adjustment to be applied to the gun in a vertical plane. That is, for a given definite range, the gun must be adjusted to a definite sight angle in a vertical plane. The deflection correction, which will be called sight deflection, is calculated from the velocity and direction of the wind, drift, speed, direction of ship and target, etc., as calculated, and is an angular adjustment to be applied to the un in a horizontal plane. A gun on shipboard is mounted to be adjusted in elevation on its trunnions in a plane that is perpendicular to the deck, and in a train plane which is at right angles to the elevation plane. It is clear, therefore, that when the ship is rolling so that the gun support inclines from the horizontal, the gun is not elevated and trained in true vertical and horizontal planes respectively, but in planes at angles to these planes, the magnitude of the angles depending on the inclination of the ship.

It is a function of this system and aparatus to compensate for the inclination of the trunnions of the gun l0.

It is to be understood that it is assumed in this application that when the ship is on even keel its deck will be truly horizontal. In practice it may be that the dick is not in a true horizontal plane when the ship is on even keel; in such cases, a reference plane must be established. It is intended for the sake of simplicity to use the term deck to denote the reference plane, whether it be the actual ships deck or the established plane. Thus, if the deck is truly horizontal when the ship is on even keel, then the term deck denotes the actual deck of the ship; if not, the word deck denotes the calculated reference plane.

Referring to the drawings, this invention has been shown as applied to the control of guns on war-ships. It is to be understood, however, that the invention is not limited to this application but has general application to those systems where guns and the like are mounted on any swaying foundation or platform.

As shown in Fig. l, a gunimtll is mounted in a turret 10a, or other suitable mount on a ship, and is controlled by means of a sighting device or director H, usually situated at some position remote from the gun, such as at some suitable position aloft. It will be understood that usually a plurality of guns will be controlled by the director, but for the sake of simplicity but a single gun is shown. The trunnions lflb of the gun II] are mounted to rotate on a suitable mount Hlc. The gun is arranged to be adjusted in elevation on its trunnions which rotate on an axis :r-x that is perpendicular to the plane of the drawing in the position of the gun shown in Fig. 1, and which is parallel to the deck of the ship. The mount [c rotates in a train plane on an axis y-y which is perpendicular to the axis :c-x and to the deck of the ship.

The director ll comprises a pedestal [2 (Figs. 2 and 3) which is provided with feet l3, usually three in number, positioned 120 apart. Each foot l3 has one levelling screw l4 and two holding-down bolts l5. The pedestal is mounted on the deck [6 of a suitable director station, which deck is approximately parallel with the deck of the ship. The levelling screws provide means for levelling the director relative to the reference plane, or deck, of the ship.

All of the controlling units or elements of the director are supported by the pedestal I2 and are arranged to rotate around it in a train plane. The elements are mounted on and supported by a frame H, which is freely rotatable in train on suitable bearings (not shown) carried by the pedestal.

Arranged on and carried by the lower end of the pedestal I 2 is a relatively large gear I8, with which a worm gear l9 meshes. The latter gear is mounted on a shaft I 9a (Fig. 1) which is driven by trainer handwheels 20. The handwheels 20 drive a shaft 2| through gears 2Ia. Mounted on this shaft to rotate with it, but having sliding motion relative to it, are a pair of gears 2| 1) and 210 of relatively small and large diameters respectively. The smaller gear meshes with a gear 2|d, while the larger gear 210 is intended to mesh with a gear 2le, smaller than the gear 2ld. The gears 21b and 2|c are selectively controlled to mesh with the gears 2 Id and 2 I6 respectively by means of a clutch member Zlj. The gears 21d and 2le are secured to a shaft Zlg, which is connected with the shaft 19a by means of gears 2lh. The director may be revolved rapidly in train to bring it onto a target by throwing the gear 2lc into mesh with the gear Me, and is accurately adjusted when approximately on the target by means of the gears 2| b and Zld. It will be observed that when the handwheels 20 are rotated, the frame l1 and the mechanism supported thereby will be turned in a train plane. It will be understood that it is the function of the training mechanism to bring the director to bear on a target so as to measure its hearing. The director is provided with a training sight or telescope 23 (Figs. 2 and 3) to assist the trainer in bringing the director to bear on the target.

The director further comprises elevation sighting means. The elevation sighting means consists of an eye-piece 24 (Figs. 1, 2, and 3) through which the target is observed; the line of sight 24a is directed to the eye-piece by an adjustable mirror 25 (Fig. 1) and a suitable prism (not shown) arranged in the eye-piece 24 to direct the path of light from the mirror 25 into a path through the eye-piece and to the eye of the observer, who is known as the pointer.

The adjustment of the director in elevation is made by adjusting the angular position of the mirror 25 about an axis at right angles to the train axis of the director II; that is, about an axis which is perpendicular to the axis about which the director is moved in train. The mirror 25, as shown in Fig. 1, is mounted on a shaft 26, which is perpendicular to the training axis of the director. The mirror 25 is adjusted in elevation by means of handwheels 21 which are connected to drive the mirror by means of a mechanical drive which is arranged so that certain corrections may be introduced into it, as will be pointed out in greater detail hereinafter.

The mirror 25 is adjusted in elevation by the handwheels 21 so that the line of sight is ad- 45 justed to and maintained in the proper relation to the elevation of the gun In. That is, the

"pointer adjusts the mirror 25 so as to bring the cross-hairs of the sight onto the target at the proper point in the roll of the ship that it is de- 60 sired the fire of the gun shall take place. Usually, the deck of the ship will not be horizontal at the instant of fire. The angle between the ships deck at the instant of fire and the line of sight is known as the director correction angle and is 55 introduced by controlling the position of the line of sight in the proper relation to the elevation of the gun, as pointed out previously.

The director I I is moved in train and the line of sight 24a is moved in elevation at the same 60 speed, while certain other elements of the mechanism operate at relatively high speeds. The speed of the director in train is 1 speed and so is that of the line of sight 24a. In view of the fact that the line of si ht moves through an an- 5 gle twice as great as the angle through which the mirror moves, the mirror 25 is operated at onehalf speed.

The angular adjustment to be applied to the gun in elevation above the deck of the ship is 70 introduced at the director. This adjustment is known as the gun elevation order and is applied by turning the handwheels 21. It is transmitted directly to the gun ID. The gun elevation order is the total gun elevation above the deck 7 at the instant of fire. That is, the gun elevasion.

a ifiiiil an iiiUUHt tion order will be equal to "sight angle, which. as pointed out previously, is the calculated correction to be applied to the gun in elevation for a definite range of the target corrected for the "director correction angle, trunnion tilt and vertical parallax.

The sight angle is calculated on the assumption that the ships deck is horizontal and is introduced into the director by means of a handwheel 28 (Fig. 1). The sight angle is calculated by suitable auxiliary means (not shown), such as a range keeper, located at some remote station, usually in the plotting room of the ship. The value of the calculated range of "sight angle is transmitted by suitable means to the director where suitable reproducers of the angles 29 and 30 are located, and the adjustment is introduced by the handwheel 28. While sight angle may be transmitted from the range keeper to the director by any suitable motion transmitting system, preferably an alternating current system of the selfsynchronous type will be used wherein the transmitting and reproducing devices are similar in construction and are each provided with a polycircuit armature winding and a single circuit field winding. As sown diagrammatically in Fig. 4, the transmitting devices 29a and 30a, located at the range keeper, and reproducing devices 29 and 30 may each be provided with a poly-circuit armature winding 3| which is physically similar to a three-phase bi-polar, Y-connected armature winding, and which is mounted on a stator memher; and each is further provided with a single circuit field winding 32. The transmitters and reproducers are connected together by sets of three conductors 33 connecting like Points of their armature windings, as shown in Fig. 4. The field windings 32 of each set of connected instruments are connected to a suitable source of alternating current supply 33a. The field winging induce alternating electromotive forces in the circuits of their respective armature windings, the relative magnitude of the electromotive forces in the respective circuits of the armature windings depending upon the angular relation of the field windings therewith. When the rotors of each set of the transmitters and reproducers 29a, 30a and 29, 39 are in angular agreement, the electromotive forces induced in the various circuits of the armature windings are equal and opposite and, therefore, no current is produced. However, when the transmitter is turned and held in a new position, this voltage balance no longer exists, whereby currents are caused to flow in the armature windings, and a torque is thereby exerted upon the rotor of the reproducer, which torque turns the rotor into a position in which the voltages are again balanced; in this position, the rotors will again be in angular agreement. In this particular case, low and high speed transmitters of motion 29a. and 30a and low and high speed receivers 29 and 30 are employed in order to provide greater accuracy of transmis- The rotors of the transmitters 29a and 36a, as shown, are connected together by gearing 332) which operates the rotor of the transmitter 30a at a high speed relative to the rotor of the transmitter 29a. In this particular case, the ratio of operation between the low and high speed transmitters 29a and 39a is 4 to 216. The rotor of the low speed transmitter is operated by suitable means indicated diagrammatically by a handwheel 33c.

The reproducers 29 and 30 drive indicator dials 34 and 35 respectively (Figs. 1 and. 4) which cooperate with ring dials 36 and 31 driven by the handwheel 28. The dials 34 and 35 are provided with indices which are aligned with similarly arranged indices on the ring dials 36 and 31 when the dials 34 and 35 are in their zero positions. When the receiving devices 29 and 30 drive the dials 34 and 35 from their zero positions to indicate the sight angle calculated by the remote range keeper, the handwheel 28 will be turned in order to cause the dials 36 and 31 to follow the indices on the dials 34 and 35 to bring them into alignment with them. In doing so, the correction for sight angle is automatically introduced into the director by means of a shaft 38. The handwheel 28, as shown, is mechanically connected with the ring dials 36 and 31 and the shaft 38 by means of gears 39 connecting the handwheel 28 to a shaft 40; the shaft 40 carries a worm 4| which meshes with a worm wheel 42 carried on a shaft 43. Mounted on this shaft is a spur gear 44, which meshes with a spur gear 45 that is connected to the ring dial 36 to drive it. Also mounted on the shaft 43 is a spur gear 46 which drives a shaft 41 through a shaft 48. The gear 46 is connected with the shaft 48 by means of a gear 49 and the shaft 48 is connected with the shaft 41 by means of spur gears 50 and 5|. The shaft 4! drives the ring dial 31 through spur gears 52 and 53, and the shaft 38 through bevel gears 54. The gearing between the dials 36 and 31 introduces a velocity ratio of 6:216. The shaft 38 is driven at a speed 216 times as great as the line of sight 24a.

The shaft 38 introduces the calculated value of sight angle into mechanism 56 which corrects the angle for tilt of the gun trunnions and issues it from the mechanism as sight angle corrected for trunnion tilt, which angle hereinafter will be known as fcorrected sight angle. This angle is issued from the mechanism 56 by means of a shaft 51. The trunnion tilt correction mechanism 56 will be described in greater detail hereinafter.

Sight deflection, which is utilized to generate the adjustment to be applied to the gun |'0 in train, is introduced into the director mechanism by means of a handwheel 58. Sight deflection is calculated from the velocity and direction of the Wind, drift, speed, and direction of the ship and target, etc. and is generated inthe range keeper referred to above. The value of sight deflection thus computed in the range keeper is transmitted to the director by a motion transmission system similar to that between the range keeper and the sight angle dials 34 and 35 with the exception that in the case of sight deflection a single speed transmitter and reproducer only is used. As shown, a reproducer 59 of the sight deflection angle is provided in the director; its transmitter has not been illustrated. This reproducer drives an indicating dial 69. The handwheel 58 drives a ring dial 6| which co-operates with the dial 66 as do the ring dials 36 and 31 with their dials 34 and 35. The handwheel drives the dial through a shaft 62 to which the handwheel is connected by a worm 63 and a wormwheel 64; the shaft 62 drives a shaft 64a by means of bevel gears 65 and 66 and the shaft 64a in turn drives the dial 6| through spur gears 61 and 68. The shaft 62 also functions to introduce deflection correction into the trunnion tilt mechanism 56. When the dial is operated from its zero position by the reproducer 59 in response to a generation of sight deflection in the range keeper, the handwheel 58 is turned to bring the ring dial 6| into agreement with the dial 80 and in doing so operates the shaft 62 to introduce sight deflection" into the trunnion tilt mechanism 56. This mechanism, as will be pointed out in greater detail hereinafter, utilizes the sight deflection introduced by the shaft 62, modifies it in accordance with the tilt of the gun trunnions and issues it by means of a shaft 69 as the sight deflection compensated for trunnion tilt. This value, which will be known hereinafter as corrected sight deflection, is used to generate the proper adjustment of the gun in train. The shaft 62 is driven at 216 speed.

The "sight angle correction and the sight deflection, as pointed out previously, are computed on the assumption that the trunnion axes of the gun lie in a horizontal plane, and that the gun is elevated in a vertical plane and trained in a horizontal plane. When the deck of the ship is inclined, it is clear that it is no longer possible to adjust the gun in vertical and horizontal planes. The mechanism 56 introduces corrections continuously compensating for tilt of the gun trunnions caused by cross roll of the ship across the line of sight.

The trunnion tilt mechanism 56 is shown in detail in Fig. 5. In this figure, it is to be noted that the shafts 38, 51, 62 and 69 do not occupy the same positions relatively to each other that they do in the diagrammatic illustration shown in Fig. 1. The shafts have not been shown in the diagrammatic form of Fig. 1 in the same positions relative to each other that they occupy in the detailed disclosure of the trunnion tilt mechanism shown in Fig. 5 in the interests of simplicity of disclosure.

The trunnion tilt mechanism 56, as shown in Fig. 5, comprises a mimic gun mounted in a gimbal system. The gimbal system is so arranged that the mimic gun can be adjusted in elevation and in train in planes representing the true vertical and horizontal planes respectively, whereby the calculated sight angle and sight deflec-- tion may be applied to the mimic gun. The mimic gun may be moved in these planes to a position that the gun l8 would occupy in space if adjusted when the deck of the ship is horizontal. In other words, the mimic gun 10 can be elevated and trained so as to generate sight angle measured in a plane representing a plane perpendicular to the deck of the ship and to introduce sight deflection in a plane representing a plane parallel to the deck of the ship. In addition, the gimbal system is arranged so that the trunnions of the mimic gun can be shifted with reference to the planes representing the true vertical and horizontal planes in accordance with the cross roll of the ship about the line of sight so as to cause the mimic gun to occupy the position in space with reference to the planes representing the true vertical and horizontal planes that the gun 18 would occupy in space with reference to the true vertical and horizontal when the ship's deck is inclined and the elevation and train adjustments of the gun I8 have not been compensated for the tilt of the ship. The difference of adjustments the mimic gun 10 has in elevation and train measured in the planes representing those perpendicular to and parallel to the deck of the ship, and the adjustments it has in elevation and train with reference to the planes representing the true vertical and horizontal after it has been shifted in accordance with the inclination of the ship, are measured and utilized to calculate the correct adjustments to be applied to 8 the gun l8 so that it can be adjusted to its correct position in space with reference to the true vertical and horizontal.

The mimic gun 10, as shown, is provided with trunnions II, which are journaled in bearings provided for them in the opposite sides of a square ring I2 to rotate on an axis :c'a:'. The ring 12 is mounted in a square ring 13 in bearings to rotate on an axis y'y' which is perpendicular to the axis m'--:z:'. The specific means mounting the ring 12 in ring 73 will be described below. The ring 13 is provided with trunnions 13a and 131) which are mounted in fixed bearings 14 so as to rotate on an axis o-a fixed with relation to the ship. That is, the mimic gun 18 is mounted in rings 12 and 13 so as to rotate on axes .r'a: and y'--y corresponding to the axes of rotation o:a: and y-y of the main gun II], which are respectively parallel to and perpendicular to the deck of the ship. It is contemplated that the mimic gun 10 will be moved on the a:'-a:' and y'--y' axes to generate the sight angle and sight deflection, as calculated, and as generated in the shafts 38 and 82 respectively.

The shaft 38, as shown, is mechanically connected to the mimic gun 10 through a differential 15 which drives an output shaft 16 at 108 speed; the shaft 18 is mechanically connected with the planetary gears 15a of the differential, while the input gear 15b of the differential is mechanically connected to the shaft 38 through spur gears 11. The shaft 18 is connected with a worm shaft I8 through spur gears 19, the worm shaft 18 having a worm which meshes with a worm wheel 8| mounted on a shaft 82. The shaft 82 is connected with a shaft 83 mounted in the axis y'--y by means of bevel gears 84 so as to drive the shaft 83 at 1 speed, and the latter shaft is geared to rotate the mimic gun trunnions H at 1 speed by means of bevel gears 85. In view of the foregoing arrangement, the value of sight angle as calculated in the range keeper and introduced into the director by the handwheel 28 is applied to the mimic gun 10 about its axis :c'm'. The function of the differential 15 will be described presently. The shaft 83, it will be observed, also functions to interconnect the rings 12 and 13 at the top and to pivotally support the top of the ring 12.

The calculated value of sight deflection is imparted to the mimic gun 18 from the shaft 82 through a differential 86. As shown, the shaft 82 is connected to the input gear 86a of the differential by spur gears 81. The output gear 861) of the differential is driven by the planetary gears 88c and is connected with a shaft 88 by spur gears 89 and 90. The gearing between the shafts 62 and 88 reduces the speed from 216 in the shaft 82 to 108 in the shaft 88. The shaft 88 drives a shaft 9| which is mounted to rotate on the fixed axis aa about the right hand trunnion 13b of the ring 13, as viewed in Fig. 5, at one speed through a worm 92 mounted on the shaft 88 and a worm wheel 93 meshing with it and mounted on the shaft 9|, The shaft 94 is mounted to rotate in the ring 13, as shown. The shaft 94 is geared to a shaft 91 to operate it at one speed through bevel gears 98. The shaft 91 is mounted in the axis y'-y' and is secured to the ring I2 to turn it on this axis. In view of the foregoing arrangement, it will be observed that the sight deflection calculated in the range keeper and introduced by the handwheel 58 is applied to the mimic gun 10 to drive it at one speed about the axis y'--y'. The shaft 91, as shown, is extended to be 33, GEOMifltilUAl. IlIoifiUIi/ILN it. seems item received in the lower part of ring 13 so as to plvotally mount the lower portion of ring 12 in the ring 13.

The functions of the differentials 15 and 86 will now be explained. It will be observed that when the shaft 62 is operated to move the mimic gun 10 in train about its axis yy' to introduce sight deflection as calculated, the gears 98 will impart motion to the ring 12 about its axis y'y'. When the ring is thus moved, the bevel gear 85 on the trunnions 1| will be rotated on the gear 85 associated with it on the shaft 83 and, therefore, will move the mimic gun 10 in elevation from its adjusted sight angle position. To compensate for this, the differential 15 is operated to introduce this angle in the reverse direction and therefore hold the mimic gun in its correct adjusted position. As shown, the gear 150 of the differential is mechanically connected with the differential 86 by means of a shaft I00, which at one end is connected with the input gear 150 of differential 15 through the bevel gear IOI secured to the gear 150 and a bevel gear I02 meshing with it and mounted on the shaft I00. The other end of the shaft I is connected with the output gear 861) of differential 86 by means of a shaft I03; the shaft I00 is connected with shaft I 03 by bevel gears I04, while the shaft I03 is connected with the output gear 8611 by means of the spur gear I05 which meshes with the spur gear 90 mounted on the shaft 88. The shaft I03 is operated at 216 speed, the shaft I00 at 216 speed and the shaft 16, as before when operated by shaft 38, at 108 speed. It will be observed, therefore, that when the shaft '62 is operated to introduce sight deflection, the mimic gun is adjusted not only in train, but tends to move from its adjusted position in elevation; the elevation controlling shaft 16, however, i operated from the sight deflection input shaft 62 by means of the differentials 86 and to introduce in a reverse direction the same angle that the gun 10 would be moved by the introduction of sight deflection. Consequently, it is held in its correct adjusted position in elevation. The differential 86 has a further function which will be described presently.

The mimic gun 10 is mechanically connected with the corrected sight angle and corrected sight deflection shafts 51 and 69 so as to impart motion to these shafts in accordance with the adjustments of the mimic gun in elevation and train by the following mechanism: The muzzle 10a of the mimic un 10 is pivotally secured to a semi-square ring member or bail I06 that is carried by a square ring or bail I 01. The ring I01 is mounted to rotate on an axis bb fixed with relation to the ship and arranged at right angles to the fixed axis a-a, and further, intersecting it at the point of intersection P of the axes :r'-:c and y'-y'. The bail I06 is provided with trunnions I06a pivoted in ring I01 to rotate on an axis 0-0, and arranged so that when the rings 12 and I01 occupy their positions shown in Fig. 5, with the axes b-b and yy' coinciding, and with the line of fire ,of the mimic gun lying in the axis H, the trunnions I06a and axis 0-0 will lie in the axis :1:'a:.

It will be observed that when the mimic gun 10 is adjusted in elevation or in train, it will carry the bail I06 with it. The motions of the bail are impartedto the output shafts 51 and 69, respectively. For this purpose, a segmental gear rack I08 is secured to one of the trunnions mm of the bail I06 (the left-hand trunnion, as viewed in Fig. 5) so as to move with the bail. Meshing with the rack I08 is a similar rack I09 which is secured to a shaft IIO. This shaft is mounted in the adjacent upright arm of the ring I01, as 5 shown in Fig. 5.

The shaft H0 is connected with a shaft III by means of bevel gears H2. The shaft III rotates in the fixed axis b-b, and is mechanically connected to drive the corrected sight angle output shaft 51 through a differential H3. As shown, the shaft II I is connected with the input gear 31; of the differential by means of spur gears I I4, one connected with the input gear I I3a and the other with the shaft I I I. The output gear II3b is connected with the output shaft 51 by means of spur gears II5. By reason of the foregoing connections between the bail I06 and the output shaft 51, the latter member is caused to generate the angle of elevation imparted to the mimic gun 10. The bail I06 and gear segment I08 move at 1 speed, the segment I09 and the shaft III at 4 speed, while the corrected sight angle shaft 51 is driven at 36 speed.

The adjustment of the mimic gun 10 in train, i. e. its deflection correction is transmitted to the corrected deflection shaft '69 directly from the ring I01. This ring, as shown, drives a segmental rack II6 with which a spur gear II1 mounted on the shaft 69 meshes. It will be observed that movement of the mimic gun 10 in train causes the bail I06, the ring I01 and the rack I I6 to move with it, and hence, generate its train adjustment in the output shaft 69. The ring I01 and rack II6 operate at 1 speed and the shaft 69 at 6 speed.

The function of the differential H3 is similar to that of the differential 15. Thus, it

will be observed that when the ring I01 is moved to introduce deflection into shaft 69, it will carry the shaft IIO with it as a body around the axis bb. This motion, of course, imparts motion to the shaft III and would vary the sight angle output in the shaft 51 by an amount proportional to the deflection output in shaft 69. However, a like motion of equal magnitude is subtracted in the differential II3 so that the shaft 51 remains uninfiuenced by the operation of the ring I01. This is accomplished by operating the input gear II3b of differential II3 by means of spur gears H8 and H9, the former connected to the planetary gear I I 3b and the latter to the ring I01. When the ring I01 in turning tends to displace the shaft 51 through a certain angle, an equal and opposite angle is subtracted in the dif- 55 ferential, whereby the shaft 51 is uninfluenced by deflection correction.

It will be remembered that the axes a;':c and y'-y' intersecting at right angles to each other at the pivot of movement P of the mimic gun 10 represent the axes about which the main gun I0 moves, that is, the axis a:'-ar' represents the axis :c-a: of the main gun parallel to the plane of the deck and about which the main gun I0 moves in elevation, while the axis y-y' represents the axis y-y of the main gun perpendicular to the deck and about which the gun I0 is moved in train.

The mutually perpendicular fixed axes 0-11 and b--b represent true horizontal and vertical.

axes in space; the axis c--c represents the axis about which the calculated sight angle is measured; and the axis bb is the axis about which the calculated sight deflection is measured. If there is no cross roll, the outputs of sight angle and sight deflection shafts 51 and 69 will be equal to the calculated values of sight angle and sight deflection" introduced by the shafts 38 and 62. If there is a cross roll, the mimic gun 10 continuously occupies the position in space with reference to the true vertical and horizontal that the main gun I would occupy, if the calculated values of sight angle and deflection were applied to it and these values were not compensated for cross roll. As a result of this, the sight angle and sight deflection in shafts 51 and 69 are continuously compensated for cross roll of the ship.

In order to compensate for cross roll of the ship about the line of sight, suitable means are provided for tilting the trunnions of the mimic gun 10 in accordance with the roll of the ship. For this purpose, the ring I3 carrying the ring 12 in which the mimic gun is mounted is tilted on its fixed bearings 14 on the axis aa by an angle equal to the angle of cross roll, and is shifted in its position to measure continuously the angle of cross roll of the ship as it varies.

The angle of cross roll is measured by a cross level sighting device I20 (Figs. 1, 2, and 3). This device comprises an eye-piece I2I, and mirrors I22 and I23 (Fig. 1). The mirrors, as shown, are arranged at right angles to each other so as to bring the opposite fields of the horizon to the eyes of the observer. A prism I24 directs the lines of sight from the mirrors to the eye-piece I2I. The mirrors are mounted on a shaft I25 which is driven by handwheels I26. The handwheels I26 drive a shaft I21 through bevel gears I28. The shaft I21 drives a shaft I29 through spur gears I30, which in turn drives the mirror shaft I25 through gearing I30a.

It will be understood that the observer operates the handwheels I26 to keep the horizon continuously on the horizontal cross-hair of the sighting device. In doing so. the observer automatically generates the angle of roll across the line of sight of the director, which, of course, is maintained on the target. The shaft I29 is driven at 108 speed, which speed is reduced to /2 speed in the mirror shaft. This, of course, moves the line of sight of the device I20 at 1 speed, because the line of sight is moved at twice the speed the mirror is moved.

The shaft I29 drives a shaft I3I at 108 speed through a shaft I32 connected to the shaft I29 by bevel gears I33 and to the shaft I3I by bevel gears I34. The shaft I3I drives the ring 13 on its axis a--a at 1 speed by means of a worm gear drive comprising a worm I35 (Fig. mounted on shaft I3I and a worm wheel I35 meshing with it and mounted on one of the trunnions 13b of the ring 13, the right hand trunnion, as viewed in Fig. 5.

In view of the foregoing arrangement, it will be observed that when the observer at the eyepiece I2I operates the handwheels I26 to hold the sight on the horizon, he will at the same time operate the ring 13 on its fixed axis a-a to continuously measure the angle of cross roll. The ring 13 when thus operated moves the mimic gun trunnions 1I through the same angle, and the resulting movement of the muzzle of the mimic gun in space modifies the calculated values of sight angle and sight deflection to generate the corrected sight angle and the corrected sight deflection adjustments.

It will be observed that when the ring 13 is rotated on its axis a--a by the cross level shaft I3I, it will swing the shaft 94 in an are about this axis, and hence, will impart a rotary motion to the shaft 94 on its own axis from the gear 95. This motion of the shaft 94, unless compensated for, would rotate the gears 98 and hence, the ring 12, and thereby disturb the train adjustment of the mimic gun. The angle through which the shaft 94 would thus have moved the mimic gun in train is introduced in the differential 86 from the shaft I3I by spur gears I31, I38 and I39 and shaft I39a, which shaft is connected with planetary gears 860 of the differential 86. Thus, when the shaft I3I is rotated, the difierential is operated by the shaft I3I to introduce an angle in train to the mimic gun equal and opposite to that introduced by the shaft 94 revolving on the gear 95, whereby the mimic gun holds its adjusted position in train. Moreover, when the position of the ring 13 is shifted, the adjustment of the mimic gun in elevation tends to vary because of the interaction of the gearing 84. This is compensated in the differential 15 which is driven from shaft I3I through the differential 86 so as to cause the mimic gun to hold its corrected adjustment in elevation.

The operation of the mechanism 56 may be better understood by reference to Figs. 6 to 11 inclusive. Assuming that the parts of the mechanism 56 are in their positions shown in Fig. 6, and that the shaft 38 is operated to introduce sight angle e, as calculated, then the mimic gun is moved through the angle e from its position shown in Fig. 6 to its position shown in Fig. 7. This operation is shown diagrammatically in Fig. 9 where the mimic gun is moved through the angle e from its dotted line position to its solid line position. When the shaft 62 is operated to adjust the mimic gun in train by the calculated sight deflection angle d, the mimic gun is moved from its dotted line position in Fig. 10, which corresponds to its full line position in Fig. 9, to its full line position in Fig. 10. This is the position that the mimic gun takes due to the calculated values of sight angle and sight deflection and is the position that the main gun I0 should take when the deck of the ship is horizontal. When the ring 12 is inclined through an angle of cross roll or (Fig. 8) in response to the operation of the cross level shaft I3I, it inclines the ring 12 and the gun trunnions II and thereby causes the mimic gun to describe a portion of a surface of a cone about the point P from the full line position of Fig. 10, which is represented in dotted lines in Fig. 11, to the full line position of Fig. 11. The muzzle 10a is the mimic gun, therefore describes a curve from its dotted line position in Fig. 11 to the full line position in this figure, which curve is a portion of the base of the cone described by the mimic gun in moving between these positions.

When the ring 13 is inclined through angle or to cause the muzzle of the gun 10a to move from the dotted line position of Fig. 11 to the solid line position thereof, the muzzle 10a in moving pulls the bail I06 with it and causes the point of intersection of the muzzle and the bail to move through a like curve. The position of the bail I06 is thus shifted in space on its trunnions W611, and also on the ring I01 about the fixed axis b -b. The first of these movements of the bail on the trunnions I06a measures the difference between the sight angle calculated and applied by the shaft 38 to the mimic gun 10 and the corrected sight angle which the mimic gun has with reference to the true vertical and horizontal axes w-a and 12-h after it has been shifted by tilt ing of ring 13. In the case illustrated, the corrected sight angle is less than the sight angle, as calculated, and as shown in Fig. 11, and this difference is subtracted from the calculated sight angle, the resultant being applied to the shaft 51 through gears I08, I09, shafts H and III, differential I I3 and gears H5. The second movement of the bail I06 due to tilting of the ring 12, that is, its movement about the fixed axis bb, rotates the ring I01 with it about this axis and measures the difference between the calculated sight deflection imparted to the mimic gun by the shaft 62 and the corrected sight deflection that the mimic gun has in space with reference to the horizontal and vertical axes H and b-b after the mimic gun has been shifted, and transmits the resultant corrected deflection to the shaft 69 through the rack and gear H6 and Ill. In the particular example illustrated, the corrected sight deflection is greater than calculated sight deflection as shown in Fig. 11.

It will be understood that as the angle of inclination of the ships deck varies about the line of sight, the muzzle 10a of the mimic gun 10 will be weaved back and forth through a conical path by the ring 13 as the latter is moved back and forth on its axis in accordance with the cross roll of the ship. The particular conical path through which the muzzle moves depends, of course, upon the calculated values of sight angle and sight deflection that have been imparted to it.

The corrected sight angle generated in the shaft 51 is combined with the director correction adjustment and is issued to the gun as gun elevation order. The corrected sight deflection generated in the shaft 69 is combined with director in train to bring it to bear on the target and is issued to the gun as gun train order.

The corrected sight angle shaft 51 is mechanically connected to the mirror 25 through a differential I40. As shown in Fig. 1, the shaft 51 is connected with a shaft I4I through spur gears I42. The shaft II is mechanically connected to the planetary gears I40a of the differential I40; the output gear I40b of the differential is mechanically connected to a shaft I43 by means of spur gears I44. The shaft I43 carries a worm I45, which meshes with a Worm segment I46 that is mounted on the mirror shaft so as to effect a mechanical drive between the mirror 25 and the shaft I43. In view of the foregoing arrangement, it will be observed that the corrected sight angle generated in the shaft 51 is applied to the mirror 25. The shaft I43 is driven at '72 speed, while the mirror 25 is driven at A speed; the line of sight, therefore, is driven at 1 speed.

When the sight angle generated in the shaft 51 is applied to the mirror 25, the line of sight is moved from the target. The director pointer in returning the line of sight on to the target by operation of the handwheels 21 will automatically generate the corrected sight angle. The handwheels 21 are mechanically connected with the mirror 25 by means of a shaft I41 which is connected with the handwheels 21 by means of bevel gears I48. The shaft I41 is connected with the shaft I49 by means of bevel gears I50, and the shaft I49 is mechanically connected with the input gear I5Ia of the differential I5I by means of spur gears I50a. The output gear I5Ib of the differential is connected with the input gear I40c 0f the differential I40 by means of spur gears I52. It will be observed, in view of the foregoing mechanical connections, that when the the target bearing generated by moving the handwheels 21 are rotated they will impart motion to the mirror 25 through the two differentials I40 and I5I.

The differential I5I is introduced in the connection between the handwheels 21 and the mirror 25 for the purpose of introducing a correction for vertical parallax between the director II and the gun. Vertical parallax is introduced into the differential I 5I by means of a handwheel I52a, which drives a worm I53. This worm in turn drives a worm wheel I54 that is mounted upon a, shaft I55. This shaft is mechanically connected to a shaft I56 which drives the plane tary gears I5Ic of the differential I5I by means of spur gears Ia. A suitable scale I51 reading in terms of range is provided to assist in making the parallax correction. This scale, as shown, is driven from the shaft I55 through gears I51a.

It will be observed that both the introduction of the corrected sight angle from the shaft 51 and of vertical parallax correction from the handwheel I52a will turn the mirror 25 to move the line of sight 24a from the target so that when the pointer operates the handwheels 21 to return the line of sight to the target, he will automatically generate thecorrection that should be applied to the gun in elevation. In addition to these corrections, the "director correction, which is the angle between the ships deck at the instant of fire and the line of sight selected by the pointer is automatically applied by the pointer in adjusting the line of sight to bear upon the target at the particular point in the roll of the ship that it is desired fire shall take place.

The resulting elevation order, that is, the order which is the resultant of the corrected sight angle, vertical parallax correction, and director correction," known as gun elevation order, is transmitted to the turret I0a by means of a suitable motion transmission system which is similar to the transmission systems between the range keeper and the reproducers 29, 30, and 59, which have been previously described. As shown, the transmission system between the pointer and the gun I0 comprises low and high speed transmitters of angular motion I58 and I 59, which are driven by the handwheels 21 to generate gun elevation order. The handwheels 21 drive the transmitters I58 and I59 through the shaft I49, the spur gears I500. and a spur gear I60 meshing with these gears and mounted on the rotor shaft I6I of the high speed transmitter I59. The rotor shaft I62 of the low speed transmitter I58 is mechanically connected to the rotor shaft I6I through reduction gearing I63. The shaft I6I is driven at 72 speed, while the shaft I62 is driven at 4 speed. Mechanically connected with the shafts I6I and I62 respectively are indicating dials I64 and I65 which are driven at the same speed as the associated shafts. As shown, the

shaft I6I is connected with the dial I64 through gears I66, while the shaft I62 is connected with the dial I65 through gears I61.

The low and high speed transmitters I58 and I59 are electrically connected to low and high speed reproducers of angular motion I68 and I69 respectively located near the gun I0. These reproducers operate dials I10 and HI respectively so as to indicate the angle of gun elevation order. Matched with these dials I10 and "I are dials I12 and I13 which are operated when the gun is elevated so as to inform the gun pointer that the gun I0 has been elevated through the angle of gun elevation order. The gun I0, as shown, is provided with a rack I14 secured to its '15 trunnions which is operated by a worm I15 mounted upon a shaft I16. The shaft I16 is operated by handwheels I11 which are mechanically connected with the shaft I16 through a shaft I18. As shown, this shaft I18 is geared to the handwheels I11 by bevel gears I19 and to the shaft I16 by bevel gears I80. The handwheels I11 are operated to elevate the gun at 1 speed and at the same time function to drive the dials I12 and I13. For this purpose, the shaft I16 is mechanically connected to the dial I13 by means of a shaft I8I to which the shaft I16 is connected by means of bevel gears I82. The shaft I8I is mechanically connected with the dial I12 by means of spur gears I83, one of which is mounted on the shaft I8I and the other on a shaft I84. This shaft in turn is connected with a shaft I85 by spur gears I86, the shaft I85 being mechanically connected with the armature member or stator of the reproducer I68 through spur gears I81. The shaft I8I is also connected with the stator or armature member of the reproducer I69 by means of a spur gear I88 meshing with the spur gear I83 mounted on the shaft I84.

Thus, when the director pointer operates the handwheels 21, he will operate the transmitters I58 and I59 which will operate the reproducers I68 and I69 to reproduce the angle of gun elevation order on the dials I10 and HI, the dials I10 and HI being driven at 4 and '72 speeds respectively. The gun pointer operates the handwheels I11 to elevate the gun by the amount of gun elevation order by returning the dials I10 and HI to their zero positions, and at the same time drives the dials I12 and I13 to indicate the angle that the gun has been elevated.

The gun train order is the value of the targets bearing, as determined by the director, compensated for corrected sight deflection and horizontal parallax. The targets bearing is generated when the director is turned in train by the handwheels 20 to bring the sight 23 to bear upon the target. When the director is turned upon its pedestal I2 by means of the handwheels 20, it automatically generates targets bearing in a shaft I89. Supported upon the pedestal I2 is relatively large spur gear I90 which is fixed to the pedestal, and meshing with this relatively large gear is a relatively small spur gear I9I which is carried by the shaft I89, which is mounted in the rotating part I I of the director. Thus, when the director is rotated on the pedestal, motion will be imparted to the shaft I89. The shaft I89 is driven at 12 speed by the gear I90.

The bearing of the target generated in the shaft I89 is corrected for horizontal parallax by referring the bearing generated to a suitable reference point. The director itself may be the reference point, or if a number of directors are used in the system, the point may be located at the vertical axis of any one of the directors. It will be understood, however, that any suitable point may be chosen as the reference point. This particular director I I is removed from the reference point and the bearing is compensated for parallax by referring it to the reference point. The train parallax may be calculated by any suitable mechanism which is designated in general by the numeral I92. Thus, for example, the train parallax mechanism described in the United States patent to W. W. Willard, No. 1,942,079, dated January 2, 1934, may be used. In this parallax mechanism, the only variable to be considered is the range of the target and this is introduced by means of a handwheel I93, a scale I94 being provided to assist in the setting of the range. The parallax mechanism I92 generates the correct angle for parallax in a shaft I95. The generated bearing of the shaft I89 is adjusted for the parallax angle in the differential I96. As shown, the shaft I95 is connected directly with the input gear I96a of the differential I96, while the bearing shaft I89 is mechanically connected with the input gear I96b of the differential. Planetary gears I960 of the differential are mechanically connected with a shaft I91which is the output of the differential and which generates target bearing compensated for horizontal parallax. The shaft I91 is mechanically connected to a shaft I98 by means of bevel gears I99. The shaft I98, it will be observed, generates target bearing correction for horizontal parallax. This shaft is mechanically connected with the corrected sight deflection of output shaft 69 through a differential 200 whereby the targets bearing compensated for parallax and corrected sight deflection will generate gun train order, which is the angle that the gun I0 is to be adjusted in train. In other words, the targets bearing generated in the shaft I98 is combined with the corrected sight deflection generated by the shaft 69 in the differential 200. As shown, the shaft I98 is mechanically connected to the input gear 200a of the differential by means of bevel gears 20I while the shaft 69 is mechanically connected to the differential input gear 20% by the spur gears 202. The planetary gears 2000 of the differential are mechanically connected to the output shaft 203 of the differential which generates gun train order. The shaft I89, as has been pointed out previously, is driven at 12 speed, the shaft I98 is driven at 36 speed, and the shaft 203 is likewise driven at 36 speed.

The shaft 203 drives a transmitter of angular motion 204, which is the high speed unit of a motion transmission system, the low speed unit being designated by the numeral 205. The low speed unit will be driven at 1 speed through reduction gearing 206. These transmitters 204 and 205 transmit the gun train order.

A high speed indicating dial 201 is mechanically connected with the shaft 203 by means of bevel gears 208, while a low speed dia1 209 is driven from this shaft through the reduction gearing 206 and bevel gears 2I0. It will be understood that these dials indicate gun train order.

The high and low speed transmitters of angular motion 204 and 205 are electrically connected to high and low speed reproducers of angular motion 2H and 2I2 located near the gun I0. The rotor of the reproducer 2 drives a high speed dial 2I3, while the rotor of the reproducer 2I2 drives the low speed indicating dial 2I4. Cooperating with the high speed dia1 2I3 is a ring indicating dial 2I5 and a companionate dial 2I6, both of which are operated by the gun when moved in train. Co-operating'with the dial 2I4 is a dial 2I1 which likewise is driven when the gun is adjusted in train. The gun is adjusted in train by means of handwheels 2I8 which are mechanically connected with a shaft 2I9 through a shaft 220. As shown, the handwheels 2I8 are geared to the shaft 220 through bevel gears 22I, and the shaft 220 is geared to the shaft 2I9 through bevel gears 222. The shaft 2I9 is geared to the gun mount I0b to rotate the gun in train by means of spur gears 223 and 224. It will be understood that the gearing is such that the gun will be moved at one speed in train. When the handwheels 2I8 are operated to adjust the gun in train, the wheels at the same time impart motion to the dials 2I5, 2I6, and 2I1. For this purpose, the dia1 2I5 is mechanically connected to the shaft 2I9 through spur gears 225, while the dial 2I6 is directly connected with the shaft 2I9. The shaft 2I9 drives the dials 2I5 and 2I6 at 36 speed. The shaft 219 is also mechanically connected with the stator of the low speed reproducer 2I2 through reduction gearing 226 so that the stator 2I2 is driven at 1 speed. The dial 2I1 is driven at 1 speed by means of a spur gear 221 which is geared to the gearing 226.

In the operation of this portion of the mechanism, it will be understood that when the reproducers 2H and 2I2 are operated by the transmitters 204 and 205, they will turn the dials 2I3 and 2I4 to designate gun train order. When the handwheels 2I8 are operated to adjust the gun in train, the ring dial 2 I 5 is operated to cause it to follow the angle designated by the dial 2I3 to bring them into agreement. At the same time, the dial H4 is operated so as to return it to its zero position, while the dials 2I6 and 2H, the former a high speed and the latter a low speed dial, are operated to indicate the angle through which the gun is adjusted in train.

It is generally necessary to utilize the value of the target's bearing compensated for horizontal parallax generated in the shaft I91 at other points in the ship. For this purpose, the shaft I91 drives high and low speed transmitters of angular motion 228 and 229. As shown, the transmitter 228 is driven directly by the shaft I91, while the low speed reproducer 229 is driven by this shaft through reduction gearing 230. A high speed indicating dial 23I is connected to the rotor of the transmitter 228 by means of bevel gears 23Ia, while the low speed indicating dial 232 is connected to the rotor of the low speed reproducer through bevel gears 232a. It wil1 be understood that the transmitters 228 and 229 also preferably will be of the self-synchronous type similar to the transmitters 29a and 30a.

Suitable target designators or reproducers of angular motion 233 and 234 are provided, the former operating on a high speed of 36 while the latter operates on the low speed of 1. The rotors of these devices operate high and low speed indicating dials 235 and 236 respectively. It will be understood that these reproducers of angular motion are operated by suitable transmitters of angular motion located at some other director station in the ship whereby the dials 235 and 236 continually reproduce in the director station II the targets bearing compensated for horizontal parallax, if any, between the other director station and the reference point. The stators of the reproducers 233 and 234 are continuously driven by the shaft I91, the stator of the reproducer 233 being driven by this shaft at 36 speed through an intermediate shaft 231; this shaft as shown, is mechanically connected to the shaft I91 through bevel gears 238 and with the stator of the reproducer 233 through spur gears 239. The stator of the reproducer 234 is driven at 1 speed by the shaft I91 through reduction gearing 239 and a shaft 240, which is connected with the rotor shaft of the low speed transmitter 229 by means of bevel gears 24! and connected with the stator of the reproducer 234 through spur gears 242. In view of the foregoing, it will be observed that the dials 235 and 236 will be driven from their index points to indicate the bearing of the target, as determined by the remote director, whereas the stators 233 and 234 operated by the shaft I91 reamount of gun train order.

turns the dial 235 and 236 to their zero positions. Any difference between the bearings generated in the two stations will, of course, at once become apparent by movement of the dials from their zero positions. By means of this arrangement, a director which is not in control of the gun I0 can be operated by the handwheels 20 so that it will generate the same bearing as the director which is in control of the gun whereby the inactive director can take over the control when necessary without undue waste of'time. an...

In the operation of the apparatus and system, it will be understood that the director trainer will operate his handwheels 20 so as to bring the training telescope 23 to bear on the target and that he will maintain this telescope bearing on the target. I n doing so, he will generate the .targegs bearingmimthg shaft I89, which angle Ftffi'nsmitted to the differential I96 where it is compensated for horizontal parallax, and thence to the shaft I98, which introduces the bearing angle corrected for horizontal parallax into the differential 200. The value of sight deflection which will have been calculated in the remote range keeper is introduced by the handwheel 58. As has been pointed out previously in detail, this operation causes the mimic gun 10 to generate the calculated "sight deflection in train. The calculated value of sight deflection in train j GOIIWOHSIY corrected for cross roll of the ship about tnjjfineio'flsrghtmghirting"the""'miiii e gu n lg as pointed out previously?" The angle 6f cross roll, of course, is continuously introduced into mechanism 56 by the handwheels I26. The corrected sight deflection output is introduced into the differential 200 by the shaft 69. The targets bearing and corrected sight deflection are combined in the differential 200 and gun train order is generated in the output shaft 203 of the differential. This shaft operates the transmitters 204 and 205, which in turn operate the reproducers 2H and 2I2 in the turret, whereby the gun trainer is instructed to adjust the gun I0 in train by the It will be understood, of course, that the handwheel I93 will have been operated to introduce correction for horizontal parallax in terms of range.

The gunelevation order will be determined by the operation of the handwheels 21 in maintaining the line of sight 24a on the target. As previously pointed out, the director pointer operates the handwheels 21 so as to operate the mirror 25 to bring the line of sight 24a on the target in the position of the roll of the ship where it is desired the gun I0 shall be fired. The sight angle, which is the correction for the range to be applied to the gun I0 in elevation will be calculated in the remote range keeper and transmitter to the director where it is reproduced by the receivers 29 and 30. When the handwheel 28 is operated to generate in the shaft 38, the value of sight angle, as indicated on the dials 34 and 35 the alue isautornaticallyintroduced illl tlrejrunniomiilt..me ch anismgifi...where""the miifi'ic 1 is elevatgd.bytheampunt of ff sight angle; This mechanism, as has been previously pointed out, shifts the mimic gun to regenerate this value as corrected sight angle in the shaft 51 which operates through the differential I40 to turn the mirror 25 from its adjusted position. The director pointer previously had operated the handwheels 21 so as to hold the line of sight in a predetermined relation with the gun which he chose arbitrarily. When the pointer notices 19 that the line of sight is not on the target at the position in the roll of the ship in which he desires it to cross the target, he again operates his handwheels 21 to restore the line of sight to the target at the desired point in the roll. In ret11.rning the line of sight to the target, the pointer ..Qllfilfateswthewtransmitters of..angu1an.moti0n I58 and 159 to generatewtfgunelevatiomordenii...

operation....is repeated until the "pointer feels that the target is brought onto his sight at the proper point in the roll of the ship for fire.

This method of control in elevation possesses the advantage that the line of sight is weaved up and down, rather than the gun l itself, as the trunnion tilt correction is continually changed to compensate for roll and pitch of the ship.

It will be understood, of course, that the handwheel l52a will have been operated so as to introduce the proper value for the vertical parallax, whereby the gun train order takes into account the elevation of the director above the gun !0.

The gun pointer adjusts his gun in elevation in accordance with the amount and direction of displacement of the dials I16 and !1! to reproduce in the turret !0a the value of "gun train order generated in the director station.

As previously pointed out, when the gun "I is adjusted in elevation, the dials I12 and I13 are driven with the gun to iffdi'cate-the""angleof elevation, while the dials L1-!are"re turned to their zero positions. Of course, when the dials I10 and !1! are returned to their zero positions, the angle of gun train order will have been imparted to the gun. Similarly, when the gun trainer operates the handwheels 2!8 to adjust the gun in train, he will operate the ring dial M5 to follow the dial 2l3 and the dial 2" to follow the dial 2!4. The dials 2! 6 and 2H will be operated to indicate the angle of adjustment in train, while the dial 2!4 will be returned to its zero position.

In Fig. 12, there is illustrated a modified mechanism for compensating for tilt of the gun trunnions, which in general has the same construetion as that shown in Fig. 5, and which operates on the same principle. In Fig. 12, however, there are certain differences in details of construction. For example, the differentials corresponding to the differentials 15 and 86 are located in the low speed portions of the mechanism, rather than in the high speed portions of the mechanism, as is the case of Fig. 5. As shown in Fig. 12, the mimic gun 245 is provided with trunnions 246 which are mounted in a ring 241 to rotate on the axis :r':r'. The ring 241 is supported on the ring 248 for rotation in train in the axis y'-y'. This ring 248 is provided with trunnions 249 which are mounted in fixed bearings 25!) so that the ring rotates on the fixed axis a-a.

The mimic gun 245 is operated in elevation by means of a sight angle input shaft 25!, which as shown drives a worm shaft 252 through bevel gears 253. The shaft 252 carries a worm 254, which meshes with a worm wheel 255 on a shaft 256. The shaft 256 operates a differential 251; as shown, the shaft 256 is connected with the input gear 251a of the differential by means of spur gears 258. The output gear 251b of the differential 251 is mechanically connected to drive the spur gear 259 by means of a spur gear 266. The spur gear 259 drives a. shaft 26! through a spur gear 262. The shaft 26! is mounted on one of the upright arms of the ring 248, the left hand arm, as shown in Fig. 12, and functions to drive form shown in Figs. 1 and 5.

shaft 263 also mounted in the ring 248, and as shown arranged at right angles to the shaft 26!; the shaft 26! is connected with the shaft 263 through bevel gears 264. The shaft 263 is connected with the mimic gun 245 to adjust it in elevation through a differential 265. As shown, the shaft 263 is connected with the input gear 265a of the differential through the spur gears 266. The output gear 265b of this differential is mechanically connected with a shaft 261 through spur gears 268. The shaft 261 is mechanically connected to the trunnions 246 of the mimic gun 295 by means of bevel gears 269.

It will be observed in view of the foregoing that when the shaft 25! is operated it will operate the mimic gun 245 in elevation through the worm shaft 254, the differential 251, the shaft 26!, the shaft 263, differential 265 and the shaft 261. To adjust the mimic gun in elevation, the shaft 25! in this particular form of the invention is operated at 240 speed, the shaft 252 at speed, and

the shafts 26! and 263 at 1 speed, which in turn operate the shaft 261 and the mimic gun 245 at 1 speed.

The "sight angle input shaft 25! has been "shown diagrammatically as operated by a hand- Wheel 21!), but it will be understood that this shaft will be operated by a mechanism similar to the mechanism which drives the shaft 38 of the first As shown, the handwheel 210 may be connected to shaft 25! by means of a shaft 216a. which is connected with the shaft 25! by bevel gears 2111b. A scale 2100 is shown as means supplied to assist in setting sight angle. correction.

The calculated value for sight deflection" is introduced into the mechanism by the shaft 21!. which is operated by a handwheel 212 through a shaft 213, which is connected with shaft 21! by means of bevel gears 213a. A dial 21% similar to dial 2160 is provided. The shaft 21! drives a shaft 214 through bevel gears 215. The shaft 214 drives a worm 216 which in turn drives a worm Wheel 211 mounted upon a shaft 218. The shaft 218 operates through a differential 219 to drive a spur gear 286, which in turn drives a shaft 28! through a spur gear 282. As shown, the shaft 218 is connected to the input gear 2190, of the differential, the output gear 2191) of which is connected to the gear 280 through a spur gear 283. The shaft 28! is mounted in the ring 248, as shown, and is mechanically connected to the ring 241 through a shaft 284 which is secured to the ring 241 and which is connected with the shaft 28! by means of bevel gears 285. When the handwheel 212 is operated, the motion of the wheel is transmitted to the ring 241 to adjust the mimic gun 245 in train through the shaft 21 the shaft 214, the shaft 218, the differential 219, gears 283 and 288, and the shaft 28! and 284. The shaft 21! is driven at 240 speed, while the shafts 28! and 284, the ring 241 and mimic gun are all driven at 1 speed.

It will be observed that when the ring 241 is rotated on its train axis, the bevel gear 269 carried upon the trunnions 246 of the mimic gun 245 will revolve on the gear 269 carried by the shaft 261 so that the position of the mimic gun in elevation will be changed by the amount of "deflection turned in unless this movement is suitably compensated for. It is for the purpose of making this compensation that the differential 265 has been provided. It will be observed that when the shaft 284 is rotated to adjust the ring 241 in train, it will at the same time rotate a shaft 33. GiZOMETREiJM Hitsi liUlvliLli $55M bit lillUUi H 286 through spur gears 281. The shaft 286 is connected to the planetary gears 2650 of the differential 265. The gearing is so arranged that when the ring 241 is operated in train, the differential device 265 will be operated by the shaft 286 to subtract an angle equal to that through which the mimic gun would have been moved by movement of the ring 241 in train so that the mimic gun is held in its correct adjusted position in elevation. The shaft 286 is driven at /2 speed from the shaft 284.

The motions of the mimic gun 245 in elevation and train are transmitted to a suitable bail 288 which is pivoted to rotate on a ring 289 in an axis c-c; this ring in turn rotates on the fixed axis b-b. The muzzle 245a of the mimic gun is pivotally connected to the bail 288. Secured to rotate with the bail 288 is a gear segment 290 and meshing with this gear segment i a similar segment 290a which is carried by a shaft 29l. The shaft 29I is mounted to rotate in a vertical arm of ring 289, the left-hand arm as shown in Fig. 12. The shaft 29l is connected to rotate a shaft 292 mounted in the axis of rotation of the ring 289 by means of bevel gears 293. The shaft 292 drives the corrected sight angle output shaft 294 through a differential 295. As shown, th shaft 292 is connected to the input gear 295a. of the differential by means of spur gears 296, and the output gear 29% of this differential is connected to the shaft 294 through spur gears 291. In view of the foregoing arrangement, it will be observed that movement of the mimic gun in elevation will be transmitted to the shaft 294.

The adjustment of the mimic gun 245 in train is transmitted to the corrected sight deflection output shaft 298. As shown, the movement of the mimic gun in train carries the bail 288 with it and the motion of the bail is imparted to the ring 289 about its axis of rotation b-b. This motion of the ring 289 is transmitted to a shaft 299 through a gear 300 secured to the ring and which meshes with a gear 30I carried by the shaft 299. The shaft 299 is secured to the planetary gears 2950 of the differential 295 and also is mechanically connected to the output shaft 298 through spur gears 302.

The mimic gun, as has been pointed out, moves at 1 speed in elevation and train. The gear segment 290 is driven at 1 speed, the shaft 29f at 3 speed, the shaft 292 at 3 speed, while the corrected sight angle shaft 294 is driven at 24 speed. In sight deflection, the ring 289, of course,is driven at 1 speed with the mimic gun, the shaft 299 is driven at 2 speed, and the corrected sight deflection shaft 298 is driven at 6 speed.

It will be observed that when the ring 289 is adjusted in train, the gear 293 carried on the shaft 292, which controls the corrected sight angle output, rotates with reference to the gear 293 carried on the shaft 29I so that unless otherwise compensated for, the shaft 294 will be operated by the sight deflection output mechanism. It is the function of the differential 295 to make this compensation. When the shaft 299 is operated by the ring 289, it will operate the planetary gears '295c of the differential 295 to subtract an angle equal to that which is introduced into the differential by the shaft 292 in reponse to motion of the ring 289, whereby the position of the shaft 294 remains unchanged when the ring 289 is operated.

The angle of cross roll of the ship about the 22 line of sight is imparted to the ring 248 by means of a shaft 303 which is driven by mechanism similar to that which drives the shaft 131 of the form of this invention shown in Figs. 1 to 11, inclusive. The shaft 303 drives a shaft 304 through bevel gears 305 The shaft 304 drives a worm 306 which in turn drives a worm wheel 301 mounted upon a shaft 308. The shaft 308 drives one of the trunnions 249 of the ring 248, the right hand trunnion as viewed in Fig. 12, through spur gears 309 and 3l0. The shaft 303 is driven at speed, the shaft 304 at 90 speed, the shaft 308 at 3 speed, while the shaft 249, that is, the trunnion of the ring 248, is driven at 1 speed.

When the ring 248 is inclined, it functions to correct the sight angle and sight deflection corrections in the shafts 294 and 298 respectively for tilt of the gun trunnions in precisely the same fashion as does the ring 13 of the form of corrector shown in Fig. 5.

It will be observed that when the ring 248 is inclined in response to the operation of the shaft 303, the haft 281 mounted in the ring 248 will be revolved due to the interaction of the bevel gears 285 and that the motion of this shaft will tend to change the train adjustment of the mimic gun 245. This motion imparted to the shaft 28! is compensated for in the differential 219. As shown, the gear 3|0 driven by the shaft 303 also drives a shaft 3 through a spur gear 312. The shaft 3 is connected to the planetary gears 2190 of the differential 219. The gearing is so arranged that when the ring 248 is inclined, and as a result the shaft 281 tends to move from its adjusted position, the differential 219 will be operated to introduce an equal angle but of opposite sign whereby the shaft 28I, and hence, the mimic gun, hold their correct train adjusted positions.

In a similar manner, when the ring 248 is inclined, the shaft 261 carried by it will tend to rotate about the gear 259 and unless thi tendency were compensated for, the adjustments of the mimic gun 245 in elevation would be changed. The differential 251 provides this compensation. As shown, the left-hand trunnion 249 carries a gear 3l3 which meshes with a, gear 3l4 carried by a shaft 3l5. The shaft 3l5 is mechanically connected to the planetary gears 2510 of the differential 251 so that when the ring 248 is inclined, the differential will be operated to subtract an angle equal to that which would be imparted to the shaft 261 by inclination of the ring, whereby the mimic gun holds its correct adjusted position in elevation. The shaft 3l5 is driven at 2 speed by the trunnion 249.

The operation of this form of the trunnion tilt compensator is the same as that described in Figs. 5 to 11 inclusive. It will be observed, however, that the differential devices 251, 265, and 219 of the form shown in Fig. 12 are located in relatively low speed portions of the mechanism, whereas those in the form shown in Fig. 5 are located in relatively high speed portions of the mechanism. The advantage of the form shown in Fig. 5 is that the differentials can be made considerably smaller than those shown in Fig. 12, and provide greater accuracy.

The axes a:':r', y'-y', a-a, b-b, and cc correspond to the similarly indicated axes of Fig. 5.

In Fig. 13, there is illustrated still another modified form of trunnion tilt correction mechanism. In this form, the mimic gun 3|6 has a U shape, as shown, the ends of the two legs of the U being pivotally mounted upon a support 3| 1 of cross shape. The arm 3|1a of the member 3|1 supports the mimic gun to move in elevation on the axis a:a:' which corresponds to the axis :c'--.r' of Fig. 5. The arm 3|1b of the support is mounted in a ring 3|8 to rotate on an axis yy corresponding to axis y'-y' of Fig. 5.

The mimic gun 3|6 is moved in elevation to generate sight angle by means of a sight angle input shaft 3|9, which corresponds to shaft 38 of Fig. 5. The shaft 3|9 is connected to the mimic gun through a differential device 320. As shown, the shaft 3|9 is connected to the input gear 320a of the differential device by means of spur gears 32 I. The output gear 3201) of the differential is mechanically connected to a shaft 322 through gears 323. The shaft 322 in turn is mechanically connected to a shaft 324 through gears 325. The shaft 324 drives a worm 326 which meshes with a worm rack 321. The rack 321 is connected to drive a shaft 328 which in turn drives a gear segment 329. The gear segment 329 meshes with a gear 338 which drives a gear 33|. The gear 33| in turn drives a gear segment 332, which is connected to one arm of the mimic gun 3|6, the right hand arm, as viewed in Fig. 13. The gears 330 and 33| are mounted to rotate freely on the shaft 3|1c in the axis y'y. That is, the gears 339 and 33| do not drive the shaft 3| 10. It will be observed in view of the foregoing arrangement that when the shaft 3|9 is operated, it will adjust the mimic gun 3|6 in elevation through the differential device 329, the shaft 322, the shaft 324, the shaft 328, and the gears 329, 330, 33|, and 332. The sight angle input shaft 3|9 is driven at 216 speed, the shaft 322 is driven at 108 speed, the shaft 328 is driven at 1 speed, the gear 330 is driven at 1 speed, and the gears 33l, 332 and the mimic gun 3|6 are driven at 1 speed.

The mimic gun 3|6 is adjusted in train to generate sight deflection by means of a sight deflection input shaft 333. The shaft 333 is connected through a differential device 334. As shown, the shaft 333 is connected to the input gear 334a of the differential by means of gears 335. The planetary gears 3341) of the differential are mechanically connected to drive a shaft 336. The shaft 336 is connected to a shaft 331 through gears 338. The shaft 331 is connected to drive a shaft 339 through gears 34!]. The shaft 339 drives a worm 34| which in turn drives a gear segment 342. The gear segment 342 drives a shaft 343, which in turn drives a gear segment 344. This gear segment 344 meshes with a gear segment 345 which is connected directly to the arm 3| 1b of the support 3|1 so that when it is operated, it adjusts the mimic gun 3|6 in train about the axis y'y'. The shaft 333 is driven at 216 speed, the shaft 336 is driven at 216, the shafts 331 and 339 are driven at 120 speed, the shaft 343 is driven at 1 speed, and the gear seg ment 345 and the mimic gun are moved at 1 speed. It is to be noted that the vertical arm 3 1b of the support 3| 1 is mounted to rotate freely upon the shaft 3|1c. That is, the motion of the mimic gun in train does not impart any motion to the shaft 3| 1c.

The adjustments of the mimic gun 3|6 in elevation and train are imparted to a ring or bail 346. The bail is provided with trunnions 341 mounted in a ring 348 to rotate in an axis cc corresponding to axis cc of Fig. 5. The muzzle 3|6a of the mimic gun, s shown, is pivotally connected to the bail 346.

The movement of the bail 346 in elevation by .the mimic gun 3|6 is imparted to a corrected sight angle shaft 349 by means of a gear segment 359, which is secured to move with the bail 346, as shown in Fig. 13, and which meshes with a gear 35| connected to drive a shaft 352. The shaft 352 is mounted in the ring 348, as shown, and drives a shaft 353 through gears 354. The shaft 353, as well as the ring 348, are arranged to rotate in a fixed axis 22-22, which corresponds to the fixed axis b-b of Fig. 5. The shaft 353 is mechanically connected to drive the output shaft 349 through a differential 355. As shown, the shaft 353 is connected to the input gear 355a of the differential through gears 356. The planetary gears 3550 of the differential device are connected to a shaft 351, which is connected to the output shaft 349 by means of gears 358. The gear segment 350 is driven at 1 speed, the gear 35| at 4 speed, the shaft 352 and the shaft 353 are driven at 4 speed, the shaft 351 is driven at 12 speed and the shaft 349 is driven at 36 speed.

The adjustment of the bail 346 in train responsively to the operation of the mimic gun 3|6 in train is transmitted to a corrected sight deflection output shaft 359 by means of the ring 348 which drives a gear segment 360 that in turn drives the shaft 359 through a gear 36| meshing with the segment. The ball 346, the ring 348 and the gear segment 360 move at 1 speed, while the shaft 359 is driven at 6 speed from the gear rack 360.

The angle of cross roll about the line of sight is introduced into the mechanism by means of a shaft 362 which drives a shaft 363 through gears 364. The shaft 363 drives a shaft 365 through gears 366. The shaft 365 drives a worm 361 which drives a gear segment 368 attached to the ring 3|8 so as to shift its position on the fixed axis (cc in accordance with the operation of the shaft 362. The shaft 362 is driven by mechanism similar to that which drives the cross level input shaft |3| of the first form of this invention described. The shaft 363 is driven at 108 speed, the shaft 365 is driven at 120 speed,

while the gear segment 368 and the ring 3|8 are driven at 1 speed.

The differential devices 320, 334, and 355 perform functions similar to the corresponding differential devices in the trunnion tilt corrector mechanism shown in Fig. 5. Thus, it will be observed that when the ring 348 is adjusted in train responsively to the operation of the mimic gun 3|6, motion will be imparted to the sight angle shaft 353 by reason of the fact that the gear 354 attached to it will rotate on the gear 354 attached to the shaft 352. This, of course, would introduce an error into the adjustment of the sight angle shaft 349. However, when the ring 348 is adjusted in train, the angle of error that would be imparted to the shaft 349 is subtracted in the differential 355. For this purpose, the ring 348 is connected to an input gear 35511 of the differential device 355 through gears 369.

Moreover, when the shaft 333 is operated to adjust the mimic gun in train, it will be observed that the position of the mimic gun in elevation would be changed by the interaction of the gear segment 332 with the gear 33l, unless this movement were compensated for. This is compensated for in the differential device 320. As shown, the shaft 336 which is driven by the shaft 333 through the differential 334 is mechanically con- 33. GEOMETRECM INSTRUMENW.

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heated to a shaft 310 through the shaft 331, which is connected to the shaft 310 by gears 31!. The shaft 310 is mechanically connected to the planetary gears 3200 of the differential 320 through gears 312. Thus, when the shaft 333 is operated to adjust the mimic gun in train, it will operate the differential device 320 at the same time to subtract in this device the angle of error that would be imparted to the mimic gun in elevation by the adjustment of the mimic gun in train.

Furthermore, when the cross level shaft 362 is operated to adjust the position of the cross level ring 318, the gear segment 345 will rotate on the gear 344 so as to introduce an error in the train adjustment of the mimic gun, and the position of the mimic gun in elevation would tend to change by the interaction of the gearing 329 and 330. The differentials 334 and 320 compensate for these errors respectively. It will be observed that the shaft 363 is connected to the input gear 3340 of the differential 334 by means of gears 313 so that when the shaft 363 is operated to adjust the ring 3|8, the shaft 336 will at the same time be operated through the differential device 334 to operate the mimic gun to hold it in correct adjusted position in train. The shaft 336 also will operate the differential 320 through gears 3H, shaft 310 and gears 312 to hold the mimic gun in its correct adjusted position in elevation.

The operation of this form of the trunnion tilt compensator is substantially the same as that described in Figs. 5 to 11 inclusive and that described in Fig. 12. In this case, as in the case of Fig. 5, the differential devices are located in the high speed portions of the mechanism which is an advantage in that the differentials can be made smaller and operate more accurately. Furthermore, in the compensator of Fig. 13, the mimic gun 3l6 having a U shape and being somewhat larger than the mimic guns of the other two forms will have a greater mechanical strength.

It is to be noted in particular that the axes x'-:c' and y-y of the trunnion tilt compensating mechanisms are representative of the axes a::c and 11-21 about which the main gun I is adjusted, but that it is unnecessary that the axes :r'--a: and y'y bear any definite position or relationship on the ship with reference to the axes of the main gun. In other words, it is not necessary that the axis m'-a:' be parallel to the deck of the ship or that the axis y'-y' be perpendicular to the deck of the ship. These axes are merely representative and may take any positions relative to the ship. Likewise, while the axes aa and cc, and bb, are representative of the true horizontal and vertical respectively, it is unnecessary that they actually be positioned or maintained in the true horizontal or in the true vertical. They may take any position with reference to the true horizontal and the true vertical. These features are very important in that they obviate the necessity of the provision of means for maintaining a true vertical.

It is to be understood that the numerical values of the speeds of variou elements given in this specification are by way of example and are not to be interpreted as limiting the invention to these particular speeds; the speeds of operation of each of these elements may vary widely from the values given by way of example in the specification. The important feature is that in the forms of the invention shown in Figs. and 13, the dif- 26 ferential devices be located in parts of the mechanism that operate at speeds relatively high as compared with the speeds of operation of the mimic guns I0 and 3l6; in the form shown in 5 Fig. 12, the differential devices operate in relatively low speed portions of the mechanism.

While we have. shown particular embodiments of our invention, it will be understood, of course, that we do not wish to be limited thereto, since 0 many modifications may be made, and we, therefore, contemplate by the appended claims to cover any such modifications as fall within the true spirit and scope of our invention.

What we claim as new and desire to secure by 15 Letters Patent of the United States is:

1. Gun directing apparatus for a gun supported on a mount whose angular position varies comprising a member adjustable about a set of train and elevation axes, means for adjusting said member about said axes in accordance with the calculated adjustments to be applied to said gun in train and elevation respectively reckoned with reference to a set of planes fixed with reference to the earth, means for inclining the positions of said axes with reference to said mount in accordance with the inclination of the trunnions of said gun due to inclination of said mount so as to cause said member to assume a position with reference to mutually normal planes fixed relatively to the mount corresponding to the position said gun assumes with reference to said set of planes fixed with reference to the earth when said calculated adjustments are applied to it and said mount is inclined, and means for measuring the angular movement of said member with reference to said mutually normal planes.

2. Gun directing apparatus for a gun mount means mounting said mimic gun for adjustment about a pair of mutually perpendicular train and elevation axes, means for adjusting aid mimic gun about said axes to generate the train and elevation adjustments calculated to be applied to said gun on mutually perpendicular train and elevation axes respectively reckoned with reference to true horizontal and vertical planes, means for shifting the position of the trunnion of said mimic gun with reference to a second set of mutually perpendicular axes fixed with reference to said moving support and representing true vertical and horizontal axes in accordance with the inclination of the trunnions of said gun due to movement of said support so as to cause said mimic gun to assume a position in space with reference to said axes fixed with reference to said moving support that said gun assumes in {space with reference to the true vertical and horizontal when said calculated adjustments are applied to it and its trunnions are inclined by movement of said support and means measuring the angular movement of said mimic gun in train and elevation with reference to said axes fixed with reference to said moving support.

3. Gun directing apparatus for a gun supported on a mount whose angular position varies comprising a mimicgun, a support for said mimic gun, means mounting said mimic gun on said support for adjustment on a pair of mutually perpendicular train and elevation axes, means for adjusting said mimic gun on said axes to generate the train and elevation adjustments calculated to be applied to said gun on mutually perpendicular train and elevation axes reckoned with reference to true horizontal and vertical ed on a moving support, pomprisiugammimi c gun planes, WH iQLLIDCIiHiHEjaQQQUDPOYt continuously with reference to a set of ni'utfi ally perpendicular planes representative of the true vertical and horizontal and fixed with reference to said mount in ordance with the cross roll of said mount about the line--of---sight of a target so as to tilt the trunnions of said mimic gun to cause it to assume continuously a position with reference to said mutually perpendicular planes corresponding to the position said gun assumes with reference to true vertical and horizontal planes when said calculated adjustments are applied to it and the angular position of said mount is changing, a movable member connected to said mimic gun and means operated by movement of said member for generating the adjustments to be applied to said gun in both train and elevation.

4. Gun directing apparatus for a gun supported on a, mount whose angular position varies comprising a mimic gun, a member supporting the trunnions of said mimic gun for adjustment of said mimic gun in elevation about an axis corresponding to the axis of adjustment of said gun in elevation, a support for said member mounting it for rotation about a second axis perpendicular to said first axis and representing the axis of adjustment of said gun in train, means mounting said support for rotation about a fixed axis representing a true horizontal axis, means for inclining said support about said fixed axis in accordance with the inclination of the trunnions of said gun due to inclination of said mount, a member mounted to move about a second fixed axis perpendicular to said first fixed axis and representing a true vertical, and a connecting member between said mimic gun and said last named member so that said last named member is moved to measure the angular position in train said mimic gun has with reference to the first of said two fixed axes, said connecting member being arranged to measure the position said mimic gun has in elevation with reference to the second of said two fixed axes.

5. Gun directing apparatus for a gun supported on a mount whose angular position varies comprising a mimic gun, a member supporting the trunnions of said mimic gun for adjustment of said mimic gun in elevation about an axis corresponding to the axis of adjustment of said gun in elevation, a ring, means supporting said member in said ring for adjustment in train about a second axis perpendicular to said first axis, said second axis representing the axis of adjustment of said gun in train, means mounting said ring for rotation about a fixed axis representing the horizontal, said fixed axis intersecting said first l and second axes at their point of intersection,

a second ring mounted to rotate about a second fixed axis representing the vertical perpendicular to said first fixed axis and intersecting it at the point of intersection of said first fixed axis with said first and second axes about which said mimic gun is adjusted, a member connecting the muzzle of said mimic gun with said second ring, means connected to said mimic gun to adjust it in elevation and train about said first and second axes in accordance with the calculated adjustment in elevation and train to be applied to said gun, means for shifting said first ring about said first fixed axis in accordance with the angle of cross roll of said mount across the line of sight of said target, whereby the trunnions of said mimic gun are shifted with reference to said two fixed axes, the position of said second ring adjusted by said mimic gun measuring the position of said mimic gun in train with reference to the first of said fixed axes and means connected to said connecting member arranged to measure the position of said mimic gun in elevation with reference to the second of said fixed axes.

6. Gun directing apparatus for a real gun supported on a mount whose angular position varies, comprising a mimic gun, a member supporting the trunnions of said mimic gun for adjustment of said mimic gun in elevation about an axis corresponding to the axis of adjustment of said gun in elevation, a ring, means supporting said member in said ring for adjustment in train about a second axis perpendicular to said first axis, said second axis representing the axis of adjustment of said gun in train, means mounting said ring for rotation about a fixed axis representing the horizontal, said fixed axis intersecting said first and second axes at their point of intersection, a second ring mounted to rotate about a second fixed axis representing the vertical perpendicular to said first fixed axis and intersecting it at the point of intersection of said first fixed axis with said first and second axes on which said mimic gun is adjusted, a member connectin the muzzle of said mimic gun with said second ring, a pair of shafts mounted on said first ring geared to said mimic gun and member respectively to adjust said mimic gun in elevation and train about said first named axes, means for operatin said shafts so as to adjust said mimic gun in elevation and train to generate the calculated adjustment to be applied to the real gun in elevation and train, means for operating said first ring about its fixed axis so as to generate the angle of cross roll of said mount across the line of sight to said target, and means connected to said pair of shafts operating them responsively to the operation of said operating means for said first ring to compensate for the changes in adjustment applied to said mimic gun in elevation and train by the interaction of the gearing between said pair of shafts and said mimic gun and member respectively as said first ring in which said shafts are mounted is adjusted to generate said angle of cross roll.

7. Gun directing apparatus for a gun supported on a mount whose angular position varies comprising a mimic gun, a member supporting the trunnions of said mimic gun for adjustment of said mimic gun in elevation about an axis corresponding to the axis of adjustment of said gun in elevation, a first ring, means supporting said member in said ring for adjustment in train about a second axis perpendicular to said first axis, said second axis representing the axis of adjustment of said gun in train, means mounting said ring for rotation about a fixed axis representing the horizontal, said fixed axis intersecting said first and second axes at their point of intersection, a second ring mounted to rotate about a second fixed axis representing the vertical perpendicular to said first fixed axis and intersecting it at the point of intersection of said first fixed axis with said first and second axes about which said mimic gun is adjusted, a member connecting the muzzle of said mimic gun with said second ring, a pair of shafts mounted on said first ring geared to said mimic gun and member respectively to adjust said mimic gun in elevation and train about said two first named axes, a second pair of shafts generating respectively the calculated adjustments to be applied to said gun in elevation and train connected to said first named shafts respectively, the connections including respective differential de-

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