Patent GB-627684-A (GB)
Title: Improvements relating to control systems for guns or gun turrets
Filed: 1943-08-26
Abstract: 627,684. Controlling the aiming and firing of guns. SPERRY GYROSCOPE CO., Inc. Aug. 26, 1943, No. 13961. Convention date, Aug. 26, 1942. [Class 92 (i)] Apparatus controlled from the aiming movements of a gun to interrupt firing when the gun reaches a position where the line of fire is obstructed is provided with means for advancing the time of interruption in dependence upon the angular velocity of the gun and with means for advancing the time of restoration of the firing as the gun leaves the obstructed zone also dependent on the said angular velocity. The known shaped fire cut-off cams are provided with clearances to take account of the deflections in gun-fire which are independent of the angular velocity of the gun-laying movements. In the present invention, the fire cut-off cams are formed to include only the fixed components of the clearance angle and are advanced with respect to the gun movement by an amount proportional to gun velocity whereby a decreased zone of restricted fire is obtained. Fire cut-off control.-Cut-off cam 56 is rotated to correspond with the azimuth position of the gun advanced by an amount proportional to the angular velocity of the gun in azimuth. The drive is through the planetary shaft 47 of a differential gear 42, the sun-wheel 43 of which is driven from azimuth drive shaft 44, the sunwheel 41 being driven from the azimuth control handles 12 rotating about axis 14. These handles operate a hydraulic control valve through shaft 38 to produce a rotational velocity of the gun turret proportional to the extent of movement of the handle. In a similar manner, the rotation of handles 12 about axis 13 operates the elevation valve through shaft 72 and through differential 79 advances the elevation angle conveyed by shaft 83 by an amount proportional to the rate of elevation, the combined movement being conveyed by planetary shaft 86, shaft 91 and shaft 94 to the cam follower 95. The follower carries a bevelled roller 96 which, on engagement with the bevelled edge of cam 56, lifts the follower about its hinge to operate a cut-off switch 98 in the firing circuit. Cams and followers are shown duplicated to control the firing of a pair of guns. Limit-stop control.-The fire cut-off is shown associated with limit-stop mechanism which initiates deceleration of the driving motors before reaching the forbidden zones of gun movement even. though the control handle 12 is still being operated. To achieve this for combinations of elevation and azimuth motion, the curve representing limit-stop positions is moved up or down or right or left corresponding to gun elevation and azimuth rates of movement. The limit-cam 103 is driven through a differential 101 (similar to differential 42) to accord with azimuth position and azimuth rate and its follower 108 is driven from differential 106 (similar to differential 79) and shaft 110 geared to arm 131 to accord with elevation position and rate. Deceleration of the motors is effected by the interaction of the cam and follower through planetary shafts 102, 107, the relative effects on the azimuth and elevation valves depending on the relative strengths of the spring couplings 30, 73. Setting adjustments are effected by manually-adjustable couplings 48, 104, 87, 109. The coupling shown in Fig. 4 normally connects input shaft 111 with output pinion 121 through a rotary frame 117 carrying a knob 123 and pinions 116, 118 of different diameters gearing respectively with wheel 114 on shaft 111 and wheel 119 connected to pinion 121. The wheel 119 is normally locked to frame 117 by rack 122. On pressing knob 123 downwardly to disengage the lock, and then rotating the knob, the frame 117 is rotated and the gear becomes an epicyclic one to give a differential rotation to pinion 121 relatively to shaft 111. Specifications 5807/48, (as open to inspection under Sect. 91), and 663,047 are referred to.