GB579729A - Improvements in or relating to predictors for use with anti-aircraft guns - Google Patents

Abstract

579,729. Predictors for gun fire control. STANDARD TELEPHONES & CABLES, Ltd., and BANNOCK, D. Sept. 26, 1941, No. 12501. [Class 92 (ii)] Relates to predictors for use in sighting anti-aircraft guns in which the rates of elevation and training generated in following the target are multiplied by the time of flight of the pro - jectile to obtain the lead correction for setting the gun. According to the invention, a single motor drives the sights through variable-speed mechanisms each comprising two pairs of bevel wheels connected by a floating friction ring, the distances between the bevel wheels of the pairs being. adjustable to suit the rates of change of the elevation and training angles in following the target. In the form shown, the training sight 2, Fig. 1, and the elevation sight 3 are mounted on a turntable 1 and viewed by operators who rotate handles 5, 19 respectively. The drive to the training pinion 10 is through a differential gear 8 and to the elevating arc 30 through a differential gear 22 and shafts 23, 26. The drives through the differential gears can also take place from a single constant-speed motor 66, Fig. 2, through frictional variable-speed gears 183 of the expanding pulley, rigid-ring type described in Specification 443,053, [Group XXIV], the motor 66 driving the sun wheels 88a, 87 of differential gears 88, one directly, and one through the variable speed device, the planetary-pinions 88c of the gears driving training shaft 17 and elevating shaft 40 in the appropriate directions. These shafts emerge, to drive the differential gears 8, 22, from a box 65, Fig. 1, which houses the motor and variable-speed units shown in Fig. 2. When the power drive is used, clutches 16, 31 are operated and the rates of training and elevating are then passed'to rotary camoids 93, 109 which are translated by a common drive from a " time of flight " wheel 41, the products thereby obtained being added to the present bearing and angle of sight by differential gears 43, 51 respectively which pass the future values of the deflections to the gun through transmitters 48, 62. The rate-drives also act through cams 107, 116 on the pulley extensions 83, 92 of the variable-speed device. Tangent elevation is added to the elevation drive by a cam 119 which operates through a cord 118 on an arm 117 screwed to control the protrusion of the pulley extension 92.