Patent GB-740836-A (GB)
Title: Improvements in or relating to directing apparatus and the like
IPC: F41G3/08
Filed: 1953-05-11
Abstract: 740,836. Electric control systems. SOC. NOUVELLE DES ETABLISSEMENTS BRANDT. May 11, 1953 [May 14, 1952; May 16, 1952], No. 13037/53. Class 40(1) [Also in Group XXI] The sight 3 Fig. 1 in a directing device A on a launching piece 2 for setf-propelled projectiles is controlled by an anemometric device C which is adapted to displace the sight 3 in a manner dependent on the velocity and direction of the wind. An electric servomechanism B connects the directing device A to an anemometric head C adapted for correcting the directing data as a function of longitudinal and transverse components of the wind, electric current being supplied by a battery D. Direction device. The directing device A comprises a metal block 7, Figs. 4, 5 in which is journalled on a vertical axis a cylindrical nut 9 held against axial movement and having a screw 13 with a recessed head 14 housing a ball 15. In order to introduce corrections in elevation compensating the effect of the wind. the screw 13 may be driven in rotation by a reversible, electric motor 23, the feed of which is dependent on the anemometric head C. The ball 15 carried by the screw 13 abuts against a heel 38 on the end of a cradle 39 pivoting on a horizontal axis 40 in a fork 41 integral with a turret 42 mounted in the block 7 for rotation about a vertical axis.,Correction for deviation in direction is obtained by rotating the turret 42. The cradle 39 is spring biased against the ball 15 and is formed with a slideway 44 in which is engaged the sight 3. Rotation of the turret 42 is effected by a second reversible motor 48. Anemometric head. ' The anemometric head C comprises a hollow support 70, Fig. 1, in which is rotatively mounted about a vertical axis a shaft 71 driven by a reversible electric motor 73. On the upper end of the shaft is fixed a plate 74 forming the lower part of a protective cage with perforated side walls and containing a cylindrical casing 76 which has a horizontal axis Y-Y and in which is disposed a wind wheel 77 keyed on a shaft 78, Fig. 6. having an axis Y-Y. From the cylindrical casing 76 is suspended about pivots 79 a vane or flap 80, the axis Z-Z of these pivots being parallel to the axis Y.Y. On either side of the mean position occupied by the vane 80 the plate 74 carries two insulated contact studs 81, 81a either one of which this vane contacts as soon as the direction of the wind veers towards to the right or left of the vertical plane through the axis Y-Y. Conductors 82, 82a lead from the contact studs to slip rings 83, 83a on the shaft 71 and which are connected by brushes 84, 84a and conductors.85, 85a to relays 86a, 86 controlling reversing switches 88, 88a so that as the vane contacts one of studs 81 or 81a, one of the relays is energized by the battery D to drive the motor 73 in one direction or the other to bring the vertical plane containing the axis Y-Y, Z-Z parallel with the direction of the wind. Thus the shaft 78 of the wind wheel 77 is always parallel to the wind direction and rotation of the wheel is an exact function of the horizontal wind component. For detecting the velocity of the wind along this component the wind wheel 77 and shaft 78 are combined with a current modulating device comprising a small conductive star 93 provided with an odd number of equispaced arms, the star being fixed on the shaft 78 which is earthed and constituting together with the shaft a capacitor indicated by C 5 . The star 93 co-operates with two conductive points. 94, 95 symetrically disposed about the axis Y-Y so that when one arm passes near the point 94, the point 95 is mid-way between two other arms and vice versa. The point 94 is maintained at a high potential e.g. 4000 volts by connection through a brush ring 97 on the shaft 71 to a rectifying and transforming device 100 supplied by a feed device E. The point 95 is connected through a brush ring 107 on the shaft 71 to a part F of the servomechanism B. The anemometric head is completed by two sets of cams 110, 111, and 110a, 111a fixed on the shaft 71. Each of the cams 110, 110a comprises two semi-circular portions of different radii connected together by two diametrically opposed steps and they co-operate with followers 112, 112a which carry the moveable stud contacts of switches 113,113a connected by conductors 114, 114a to the parts G, Ga of the servomechanism. The follower 112 and the cam 110 are so arranged on the shaft about the vertical axis X-X that the diametrical line through the steps of the cam passes the follower when the direction of the wind in plan coincides with the plane of fire P. The cam 110a is disposed about the axis X-X with a phase lag of 90‹ relative to the cam 110. The cams 111 and 111a are respectively cosine and sine cams if the directing apparatus is for firing vaned projectiles and sine and cosine cams if gyroscopically stabilized. projectiles are being fired. Against each of these cams is resiliently urged a follower 115 or 115a carrying a slider 116 or 116a of a potentiometer 117, 117a and is connected by a conductor 118 or 118a to the part G or Ga of .the servomechanism, the potentiometer 117 oi 117a having one of its ends earthed and the farther end connected by a conductor 119 or 119a to the part F of the servomechanism. Servomechanism. The servomechanism B comprises a high tension feed device E, a frequency meter F and two follow-up, calculating, transmitting and exploiting devices G, Ga pertaining to the motors 23, 48 respectively, The device Ga pertaining to the motor 48 being identical to the device G except that the contactor 113 and potentiometer 117 are replaced by the contactor 113a and potentiometer 117a respectively. In operation, when an arm of the star 93 passes near the high potential point 94 a spark occurs which charges the capacitor C 5 . On continued rotation, an arm of the star passes near the point 95 and a spark occurs discharging the capacitor C 5  into a capacitor C, well defined pulses that correspond to the passages of the arms of the star in front of the part 95, these pulses being translated by the frequency meter F into a corresponding current feed to the potentiometer 117. The mean current in this potentiometer and hence the voltage across its terminals in proportional to the number of discharges per second, i.e. the speed of rotation of the wind wheel 77, and, as the slider 116 of the potentiometer is controlled by the cosine cam 111 (for vaned projectiles), or sine cam (for gyroscopically stabilized projectiles), there is in the conductor 118 a voltage which is proportional to the wind velocity component in the place of fire or in a plane perpendicular to the latter, i.e. the component which has to be taken into account for correcting the angle of elevation. The conductor 118 is connected to the grid of a triode V 2  which with a triode V 3  forms a double-triode of the follow-up device G, the grid of the triode V 3  being connected to a slider 137 of a potentiometer 136, movement of the slider 137 being controlled by the motor 23. If the wind comes from the right relative to the plane of fire P, the contact 113 is open so that' switch reversing relays r3 and r4 of the device G are not energized and the motor 23 rotates in one direction to move the slides 137 to a position such that the voltage on the grid of the triode V, equals the voltage on the, grid of the triode V 2 , which voltage is proportional to the wind velocity component to be taken into account for connecting the angle of elevation, thereupon rotation of the motor 23 ceases. If the wind veers to the left the contact 113 closes, the relays r3 and r4 are energized and the connections of the motor 23 and potentiometer 136 are reversed, so that the motor rotates in the opposite direction to move the slider 137 to equate the voltages on the grids of the triodes V 2 , V 3 . If the potentiometer is linearly wound, the distance between the position the slider 137 assumes and the mid-way position is proportional to the wind component to be taken into account for correcting the angle of elevation. The operation of the device Ga which pertains to the motor 48 adapted for adjusting in direction, is identical.