Patent GB-206873-A (GB)
Title: Improvements in or relating to level correction devices for ordnance
IPC: F41G3/10
Filed: 1922-05-15
Abstract: 206,873. Vickers, Ltd., and Perham, A. L. May 15, 1922. Sights and methods of sighting.-The pointer or pointers or equivalent members by which a gun is laid, without sighting, in quadrant elevation or training is connected to one cr two spirit levels or their equivalents so that when the levels are brought to the horizontal, the pointer or pointers are adjusted to compensate for the tilt of the gun platform. In a modification, the compensation is applied to a sight carried by the gun. As shown in Fig. 3, a longitudinal level C is carried by a bracket C<1> pivoted at c and geared by a sector C<2> to a pinion b carrying the elevation pointer B; and the quadrant elevation diaf A is connected by bevel gears and a shaft a<x> to a pinion a in mesh with the elevating sector a<1> carried by the gun trunnion. The bracket C' is. also connected to a rod D formed with a slotted cross-head d and adapted to be set by means of a hand-wheel D<1> and a rack and pinion d<1>. A cross level E is carried by a bracket E', Fig. 5, pivoted at e and connected through a link fx and a bell-crank Fx to another red F formed with a slotted cross-head f and adapted to be set by a hand-wheel F<1> and a rack and pinion f<1>. The rod F is moreover connected by a pin and slot f<2> to a lever H fulcrumed at h' and connected at its other end h<2> to a rack H<2> acting through a differential gear h on.the training pointers H'. The differential gear h also transmits to the pointers H<1> the training angle controlled from a distance. When the quadrant elevation is also controlled from a distance, a similar differential gear is provided for the equivalent of the pointer B. The fulcrum h<3> is adjusted along a scale of quadrant elevation H<3> so that the device constitutes a variable ratio mechanism, similar to that described in Specification 206,874, which applies to the transmitted adjustment of the training pointers H' a correction in respect of the quadrant elevation of the gun. The two cross-heads d, f, which have their slots at right-angles to each other, are engaged by a pin g on a disc G provided with a friction disc and washer device in a casing g<2> enabling the pin g to take up any position at the intersection of the slots in the cross-heads when these are set by the hand wheels D<1>, F<1>. The casing g<2> is connected by gearing to the training rack of the gun, so that after the levels have been set by the hand-wheels D<1>, F<1>, any further correction due to the training of the gun is automatically applied to the respective pointers, the friction grip being sufficient to transmit this. In a modification, Fig. 6, the cross-heads of the rods D, F operating the levels C, E are connected to an horizontally disposed friction device G<2>; a sight K is mounted on a shaft K<1> parallel to the gun; and the correction is applied to this shaft from the pivot e of the level E through a Hooke's joint E', which is in line with the gun trunnion, and acts as a variable ratio mechanism correcting the adjustment it transmits to the sight in accordance with the quadrant elevation of the gun.