Patent GB-449234-A (GB)
Title: Improvements in or connected with gun mountings for aircraft
IPC: F41A27/22
Filed: 1933-09-28
Abstract: 449,234. Aircraft gun mountings; reversing - gearing. VICKERS (AVIATION), Ltd., and WALLIS, B. N., Weybridge Works, Byfleet Road, Weybridge, Surrey. Sept. 28, 1933, Nos. 26712 /33 and 27432/34. [Class 92 (i)] A gun momting for use on aircraft comprises an L-shaped frame having its gun-supporting arm 5, Fig. 1, extending upwardly near to the side of the cockpit 4, its transverse arm 2 being carried by a power-driven turntable, the power drive, which consists of a windmill or other motor, being so arranged that the frame can be traversed in either direction around the cockpit or remain stationary. The arm 5 supports the gun 7 on an arm 6 and also an adjustable seat 8 as described in Specification 449,237. The turntable, Fig. 6, includes a fixed supporting ring 18 and a rotary ring 15 having brackets 3 to which the arm 2 of the L-shaped frame is connected. Inclined rollers 13, 14 on the ring 15 engage bevelled surfaces 17, 19, on the ring 18, the upper surface 19 being carried by a ring which is adjustable to take up play. A circular rack 16 on the ring 15 is engaged by a power-driven pinion 38 which is disengageable for manual working. The power drive from the flexible shaft 22 of the slip-stream motor 21, Fig. 1, to the pinion 38 is shown in Figs. 11, 12 and 13. The drive is conveyed through a friction clutch 24, and oppositely-driven bevel wheels 28, 29 either of which can be engaged by a dogclutch 32 feathered on the driven shaft 30 which is geared to the pinion 38 by a worm drive 35, 36. The friction clutch permits the drive to be gradually applied to the turntable and also permits the turntable to be gradually retarded before stopping. The dog clutch is operated by a sector-arm 66 keyed on a shaft 67, Fig. 11, journalled in the gearcasing, and fast with the shaft are arms 70, having cam slots 77 engaging pins 78 which contact with flanges 80 on the spring-pressed plate 25 of the friction clutch. The arrangement is such that the dog clutch is first engaged, the friction clutch engaging when the pins 78 pass to the ends of the slots 77. In the central position of the arm 66, the dog-clutch is disengaged and the friction clutch is released by the cam surface 77. The arm 66 is connected by teeth 65 with a spur wheel 64, Fig. 6, rotated coaxially with the turntable by a worm drive 60, 61, Fig. 15, connected by flexible shafts 54, 55 with a rotary dial 47 operated by the gunner. Movements of the dial in one direction or the other cause powerdriven movements of the gun mounting in the same sense as long as the dial is kept moving, the arm 66 being returned to central position by the motion of the turntable when the movement of the dial ceases. The dial 47, Fig. 16, drives the flexible shafts through oppositely driven worm wheels 50, 51, Fig. 17, and the shafts drive the worm 61 in the appropriate direction by means of the gear shown in Fig. 15, torque on the shaft which is not transmitting the drive being neutralized by the spur gearing 58, 59. Electric current is supplied for heating the gun, the gunner's clothing, or the oxygen supply to the gunner's breathing apparatus, by slip rings on the rotor of the turret. Specification 406,753 also is referred to.