Patent GB-146480-A (GB)
Title: Fire control apparatus for naval guns
IPC: F41G5/22
Filed: 1920-07-05
Abstract: 146,480. Krupp Akt.-Ges., F. Aug. 18, 1915, [Convention date]. Stability, determining and indicating. - Relates to apparatus for controlling the pointing and firing of naval guns when the ship rolls, and consists mainly in the provision of means for measuring and indicating the velocity of the angle of roll at the moment of discharge, the indications being taken into account, to apply a correct timelead to allow for the lag in the action of firing. As shown in Fig. 1, the gun H is trained by gearing T provided with coarse and fine pointers S', S' which are made to follow pointers S, S<2> controlled from distant transmitters D, C geared to the mechanism by which a hand-wheel b<1> trains the support a<2> of a gyroscopic apparatus (shown diagrammatically in part elevation and in part section) carrying sights a<12>, a<13> on its stabilized spindle a<11>. The training of the gun is corrected for drift by a hand-wheel e<1> which is geared to the stators D<1>, C' of the transmitters. Elevation is imparted to the gun by a receiver G connected to a distant transmitter F<1> which is set for range by a hand-wheel i<1> in conjunction with a scale and pointer i<3>, i<4>. In order to allow for the time lag in firing the gun when the ship rolls, the circuit of the firing electro-magnet n<9> is closed before the end of the roll in one direction or the other. This lead depends upon the constant time lag of the firing-mechanism and on the speed of roll. The speed of roll is indicated by a pointer N<1> of a galvanometer n' connected to the armature of a dynamo a<17> on the stabilized spindle a<11> of the gyroscope, the field magnets a<16> being of constant strength. The pointer N<1> is followed by another pointer n' actuated by a hand-wheel M, and this motion is transmitted through gearing to a transmitter K connected to a receiver A<6> for rotating in elevation the casing a<3> of the gyroscopic apparatus. The gearing between the handwheel M and the transmitter K includes a friction gear m<3>, p<1> of which the disk p<1 >can be adjusted radially to a disk m<3> by means of a rack and pinion p<6>, p' and a handle p' according to the time lag in the firing action of the gun. Hence the displacement in elevation transmitted to the casing a<3> of the gyroscope is made to correspond to the correct lead for the moment of firing the gun. The firing circuit includes three switches : one N' closed by hand; another constituted by the pointers N<1>, n<2>; and a third one constituted by contacts a<22>, a<23> on the casing a<3> and the stabilized frame a<10> respectively of the gyroscopic. apparatus. When the normal position of the ship is oblique, the elevation of the gun and the elevation of the casing a<3> and contact a<22> of the gyroscopic apparatus is corrected by adjusting both transmitters F<1>, K by gearing r<2> operated by a hand-wheel r<1> in accordance with indications given relatively to a fixed mark q<3> by a pointer Q on a receiver q<1> connected to a transmitter a<18> worked by the stabilized spindle a<11> of the gyroscope so that the pointer Q follows the roll of the ship. In a modification; the friction gear m<3>, p<1> for taking into account the time lag of the firing mechanism is replaced by adjustable resistances a<26>, Fig. 2, in the circuit of the dynamo armature a<16>, the galvanometer a<28> being put in shunt between one end of the adjustable resistances and the contact lever a<27> moving over these resistances.