Patent GB-830053-A (GB)
Abstract: 830,053. Aiming devices. MATHEMA CORPORATION REG. TRUST. July 11, 1957 [March 5, 1957], No. 21972/57. Class 92 The invention relates to an aiming device for a weapon for use against moving targets such as aircraft and is based on certain mathematical relationships derived from the geometrical diagrams shown in Figs. 1, 3 and 4. In these Figures M and W are points on the rectilinear path of the target, f is the plane of flight making an angle with the horizontal plane, y is the elevational angle of the target at M, 8 is the apparent direction or angle of flight which is the angle made tc the normal in the field of view of a telescope by a rotatable radial line which is in covering relationship with the longitudinal axis of the target, #γ is the elevational angular velocity of the target, ## is the bearing angular velocity in the horizontal plane passing through the point of observation O, #<SP>11</SP># the angular velocity in the horizontal plane of the circle of latitude of the target and #<SP>1</SP># is the angular velocity in the plane of flight f. The following mathematical relationship can be derived:- The invention comprises an aiming device in which by manual control of a single control member having two degrees of freedom of movement, the driving speeds for bearing and elevational dispositions of the weapon are set in accordance with observations of the target through an optical device moving with the weapon, the observation valves γ and # being used in a computer device to compute and hold constant the angle of slope # of the plane of flight f and then by a reversing device under the control of the gunner, the flight angle 8 is derived from the constant angle # and the elevational angle γ. This derived angle 8 is used for automatic setting of the single control member in one degree of its freedom of movement, thus necessitating manual control by the gunner of the single control member in only one degree of its freedom of movement in order to track and direct the weapon to the target. As shown in Fig. 5 a single manual control column 1 is universally pivoted at 2 and moves in a linear slot 4 of a guide 5 and at right angles thereto in a slot 6 in a guide 7. The guide 5 is mounted in a track 8 disposed at right angles thereto and can be displaced only in the direction of the track. The guide 7 is fixed to a track 9 at right angles thereto and can be displaced only in the direction of the track 9. The movements of the control column 1 are thereby resolved into two components at right angles to one another through displacements of the tracks 8, 9. In addition the column 1 goes through a radial slot 10 in a rotatable disc 11 which is thus rotated by the column 1 by any movement thereof except in the direction along the length of the slot 10. The disc 11 is geared to a regulator gear 14 of an automatic drive 15 controlling a motor 16 which operates when the angular setting of the motor shaft 17 deviates from the angular position of the gear 14. The shaft 17 drives through its extension 31 the rotatable marking line Fig. 2 in the field of view of the aiming telescope. If therefore the disc 11 is rotated to bring the marking line into covering relationship with the longitudinal axis of the target, the angular position of the disc 11 with respect to a datum line will be a measure of the angle 8 observed at any given moment in the telescope. Moreover in order to maintain the telescope marking line in covering relationship with the target, there will be movements of the column 1 along the length of the slot 10 and rotational movements which will rotate the disc 11. From Figs 3, 4 it can be seen that such movements of the column 1 along the slot will be a measure of the angular velocity #<SP>1</SP># in the plane of flight and the movements of the control column as a whole will be resolved into two components at right angles through displacements of the tracks 8, 9, the movement of the track 9 being a measure of the elevational angular velocity #γ while that of the track 8 is a measure of the angular velocity #<SP>11</SP># in the horizontal plane of the circle of latitude of the target. The displacement of the track 9 is through rack and pinion 29, 30 transmitted to the drive for the elevation of the gun. The displacement of the track 8 is transmitted through rack and pinion to the shaft 20 of a curved body 21 which is displaceable along the shaft 20 by U- member 23 having a nut 24 movable on the threaded shaft 26. The shaft 26 is mechanically coupled to a drive giving the elevational angle γ and the curved body 21 has such form in accordance with the mathematical relationship ####<SP>11</SP># cos γ that the displacement of a member 27 scanning the curved body is a measure of the angular velocity ##. this displacement being used to displace the gun carriage in azimuth. Thus in the first place the target is tracked through the telescope by entirely manual operation of the control column I and by the means described elevational and azimuth movements are imparted to the gun to bring it on to the target. The motor shaft displaces a nut 34 on a threaded extension 33, this displacement providing a value of the angle # by virtue of the rotations of the disc 11 and gear 14. The nut 34 in turn displaces a curved body 36 on a shaft 37, the shaft being rotated with the body 36 in accordance with the elevational angle γ of the gun. The curved body is formed in accordance with the equation cos #=sine 8 cos # in which γ is the constant angular slope for the flight plane for each radius corresponding to the points of its surface. These values for the angle # are scanned by a member 39 which displaces a rack 41 engaging a regulator gear 42 of a second automatic drive 42. This device 42 operates in such a manner that after the gunner has relinquished a push-button on the knob 3 of the column 1 at the end of a period of manual tracking, the motor 16 which through rotation of its shaft 17 gives the value #, is electrically connected to the device 42 as soon as the member 39 provides a value for the angle # which deviates from the value # established at the moment of relinquishing the bush-button. At the same time the first device 15 is electrically disconnected from the motor 16 and the device 42 controls the motor 16 so that it displaces the curved body 36 in a manner such that the angle # remains constant. Thus the angle 8 is so set by the motor 16 such that it has the value required by the setting of the shaft 37 for the value γ in order that the angle # is held constant. The controlled angle # is transmitted by the shaft 17 and gear 14 to the disc 11 whose angular position in accordance with the angle # is automatically set. The gunner is therefore only required to move the column 1 linearly along the slot 10 in accordance with the angular velocity #<SP>1</SP>#, this being done by maintaining the marking line of the telescope in covering relationship with the longitudinal axis of the target. The corresponding elevational and azimuth movements of the gun are effected by the means already described but in the semi-automatic stage of the tracking, the gunner is now required to make. only movements along the length of the slot 10, the rotating movements of the column now being automatically effected by automatic rotation of the disc 11 in accordance with the angle #. This arrangement merely directs the gun continuously at the target and a further computer device utilizing the angular values # and # may be used to derive automatically aiming-off values and these may be indicated in the optical device by points which must coincide with the target in order that the projectile should hit the target.