Patent GB-236250-A (GB)
Abstract: 236,250. Vickers, Ltd., and Gray, P. W. March 3, 1924. Sights and methods of sighting.-Relates to apparatus for controlling the aim of anti-aircraft guns by continuous mechanical calculation of the vertical and lateral deflections corresponding to the distance travelled by the target during the time of flight of the shell. According to the invention, members such as pointers B', D<1> are moved in accordance with the rate of elevation and rate of training, respectively, necessary to keep the corresponding observing sights A, A<1> on the target, and the required deflections are obtained when second members, such as pointers d<1>, C', are caused to move at the same rate as the first members B', D<1> by the operation of the deflection handles d, D. The second member in each case is operated through an infinitely variable speed device the adjustable member of which is connected to apparatus for multiplying by the time of flight, and the position of each handle d, D, which is indicated, or transmitted, to the gun station, is a measure of the deflection for a given time of flight. The apparatus shown serves to calculate the vertical deflection d and the horizontal deflection D from the known formulµ :- #sin (a Œ d) D<2># (1) Sin ## = RE x TX # sin # cos # sin # 2 #sin (alpha Œ d) #cos alpha (2) Sin D = RT x Tx Î # #sin alpha cos (alpha Œ d) where RE, RT are the angular rates of elevation and training; # = present angle of sight; and T = time of flight of shell. The handle b is rotated to keep the elevation sight A on the target and its angular movement a is conveyed to the various shafts so marked. The shaft d<1x>, through the differential gear d<xx>, causes the shaft d<2> to rotate proportionally to the angle (# Œ d). The apparatus B‹ calculates the expression sin (# Œ d) sin # in formula (1) and conveys this as radial movement of a roller b<3>, over a disc b<1> rotated proportionally to RE. The pointer B' therefore receives through a roller b<2> movement proportional to sin (# Œ d) RE Î sin # and this expression also represents the movement of a roller d<4> necessary to keep the pointer d' up to the pointer B<1>. The apparatus d‹, the part e of which receives the time of flight derived from the " height and fuse " chart E<3>, calculates the expression #sin (alpha Œ d) RE Î T Î# #sin # The term D/2 given by the cam F and the product sin # cos # given by the cam G are conveyed through a bar H to the apparatus d‹. The movement imparted to the member d' of the apparatus d‹ by the rotation of the handle d gives the vertical deflection on a dial d<8>. The right and left deflection in the plane of sight is given by a conversion chart D<5x> on rotating the handle D, so as to cause the pointer C<1> to follow the pointer D'. The pointer D<1> is operated by rotating the handle c to keep the training sight A' on the target. The term RT in formula (2) is thus obtained and combined with the term #cos (# Œ d) #cos # calculated by the apparatus C0 and with the term sin (# Œ d) sin # calculated by the apparatus B<0>. The product with the time of flight T is effected with the apparatus D‹ the part D<4> of which is moved by the lateral-deflection handle D. The fuse number is read from the chart E<3>.