Patent GB-167451-A (GB)
Title: Improvements in or relating to sighting and aiming apparatus for field guns, combined with devices for correcting for transverse and longitudinal inclinations of the guncarriage
IPC: F41G1/44
Filed: 1921-01-17
Abstract: 167,451. Schneider et Cie. Aua. 4, 1920, [Convention date]. Sights.-Relates to independent line of sight mechanism in which a sight-carrier and a tangent elevation indicator, either of which carries an angle of sight indicator, are mounted by cardan joints respectively on the two gun trunnions, and can be levelled to correct for lateral and longitudinal inclinations of the gun carriage. According to the invention, the sight carrier and the tangent elevation indicator are connected by mechanism such that both are levelled simultaneously by one gun layer for lateral inclination and by another gun layer for longitudinal inclination. In the form shown, the sight carrier C is mounted by a cardan joint D, D<1> on the trunnion a of the cradle A, and the tangent elevation indicator G is similarly mounted on the trunnion a'. The sight carrier C has an extension C<1>, cardan jointed at c<1> to a sector K concentric with the trunnion a and slidable in guides h<1> on a member H mounted to slide transversely in the gun carriage B. The tangent elevation indicator G carrying an angle of sight indicator T is similarly connected to the other end of the member H. The member H is traversable with respect to the carriage B through worm-and-rack gearing from a hand-wheel J in order to crosslevel the sight carrier C and the tangent elevation indicator G simultaneously, as determined by a spirit level O. The sectors K are rotatable from a hand-wheel N, through worm and toothed gearing on a shaft M journaled in the member H, to level the carrier C and indicator G longitudinally, as determined by the level t of the angle of sight indicator. The tangent elevation indicator comprises a casing G turning on the cardan shaft F and having a reading window g disclosing part of a tangent elevation scale on a drum P riding loosely on the shaft F, and carrying a pinion p driven through a multiplying gear from this shaft. To lay the gun, the left-hand gun layer maintains the sight V on the aiming-point by operaing the training-gear, and also cross-levels the sight carrier and the tangent elevation indicator by actuating the hand-wheel J. The right-hand gun layer first inclines the angle of sight indicator T through the given angle, and then operates the hand-wheel N to return the bubble of the level t between its marks, thereby displacing the drum P through an angle corresponding to the angle of sight. He then elevates the gun until the graduation on the drum P corresponding to the. given tangent elevation rests against the fiducial mark Q on the window g, and subsequently employs the hand-wheel N to maintain the bubble of the level t between its marks. A loose ring U, graduated identically with the drum P may be turned to record the given tangent elevation against the mark Q to act as a reminder of the setting. A modification is described in which the angle of sight indicator is mounted on the sight carrier and the two controls J and N are on the opposite sides of the gun to those shown in Fig. 1. Means for moving the sighting apparatus in the sighting plane relatively to its carrier is described. Specifications 139,517 and 140,760 are referred to.