Patent GB-199411-A (GB)
Abstract: 199,411. Vickers, Ltd., and Gray, P. W. Dec. 22, 1921. Gunnery calculators. - Apparatus for use in laying anti-aircraft guns operating on the basis that the movements of the target are projected on a horizontal plane, comprises members which are adjusted or moved by mechanical means in accordance with the initial horizontal range, the initial angle of bearing, the speed and course of the target in the horizontal plane, and the height of the target, for the purpose of predicting the future position of the target after a predetermined period such as time of flight t of the projectile. Means are also provided for determining the rate of change of height and for predicting the future height after the lapse of time t. As shown in Fig. 1, the mechanism in a casing A' is combined with a range finder A and these are mounted on a carriage adapted to be trained and elevated. The estimated course and speed of the target and the direction and velocity of the wind are set by the rate-setting member 5 by means of handles B, C and adjustable dials B<1>, C<1>, so as to adjust crank pins b, c, Fig. 3, engaging in slots in members B<2>, B<3> and C<2>, C<3>. The movements of the members B<2>, C<2> and B<3>, C<3> are mechanically added to impart movement to members R<1>, D<1> respectively, to vary the movement of the variable-speed members of range keepers to obtain the change of horizontal range and bearing. The change of horizontal range is communicated to a shaft R<2>, Fig. 2, and is algebraically added to the initial horizontal range communicated to a shaft R<3> by means of a handle R<4>, Fig. 1, operated by the height-following member 2 to displace a cam R<6> designed to impart movement proportional to the logarithm of the range to a toothed sector R<7>. This movement is combined with the movement of a second sector E<1> actuated by a cam E designed in accordance with the logarithm of the tangent of the angle of elevation of the range finder, i.e. the angle of sight, to operate a pointer H, Figs. 1 and 2, in accordance with the logarithm of the height of the target, this pointer being maintained in coincidence with a pointer H<2>, actuated by a shaft H' operated by the rangetaker, by readjusting the course and speed settings. A second following pointer H<x> initially actuated by a handle h<o> is moved in constant agreement with the pointer by adjusting a rate of change of height dial h<x>. To produce the change of range and deflection in the time of flight t the members R', D' are provided with pins r, d respectively. The pin r works in a slot in a pivoted arm r<1> carrying a slider r<2> having a pin r<3> engaging slots in members f, r<4>. The member f is set at a distance from the pivot of the arm r<1> proportional to the time t so that the distance of the member r<4> from this pivot represents the change of range in time t and this, when added to the instantaneous range, communicated by a shaft R<x> operated by the cam R', imparts to a member r<5> a movement in accordance with the predicted range. By a similar arrangement of parts, viz. pin d, arm d<1>, slider d<2>, pin d<3>, and slotted members f<x>, d<4>, the member d<4> is moved to a position representing the change of deflection in time t. The setting of the members f, f<x> is effected by gearing from a shaft f<3> actuated by a handle f<4> by the time of flight setting number 3. This gearing comprises a drum F engraved with curves so drawn that the angle of rotation of the drum is proportional to the time t corresponding to the height reading on the drum, this height being taken from a height drum H<4> operated by means of a cam actuated by the movements of the pointer H. A pin P engaging slots in the, members r<5>, d<4> is attached to a rack P<r> slidably mounted in a pivoted bar P<b> which is thus displaced in accordance with the future bearing. The spindle of the bar P<b> actuates a pointer P<b2> which is followed by a pointer P<b4> actuated by a handle PB by the predicted bearing-following number 4. The movement of the pointer P<b4> is added to the movement of a shaft T<1> operated by the training movements of the range-finder and actuating a transmitting switch PT by means of which the predicted angle of training is transmitted to the gun. By a differential gear the movements of the rack Pr and spindle P<b1> are communicated to a pivoted bar PR, Fig. 5, which thereby receives a motion proportional to the predicted range and operates two pointers PR<2>, PR<3>. Co-operating with the drums H are pointers h<4> which indicate the predicted height, being moved in accordance with the rate of change of height and the time t. The pointer PR<3> moves over a drum Ex engraved with curves representing the relation between the gun elevation and the height. The drum E<x> is adjusted by the elevation-correcting number 1 operating a handle e<2> and by the elevating number of the range finder operating a shaft e<1>. The adjustment of the drum E<x> also effects the setting of a switch E<1x> which transmits the elevation angle to the gun. The time of flight-setting handle f<4> operates a switch f<5> transmitting such time to the gun for the purpose of fuse-setting.