GB575263A - Improvements in power transmitting devices - Google Patents

Abstract

575,263. Controlling gearing screw and nut gearing. GENERAL MOTORS CORPORATION. Nov. 9, 1943, No. 18635. Convention date, Dec. 10, 1942. [Classes 80 (ii) and 80 (iii)] [Also 'in Groups XXX and XXXIII] Gearing for operating in particular the retractable undercarriage of an aircraft, comprises an electric motor 20, an electromagneticallyoperated clutch and brake 85, 72, 80 and an epicyclic reduction gear 61, 62, 49, 51 which drives,a screw shaft 41 co-operating with a non-rotatable nut 101, Fig. 3, in a casing 150 of the actuating gear. The magnet windings 88 are in series with the motor windings so that a disc 72 slidably connected to an input member 55 of the reduction gear is clutched to the driving disc 85 connected to the motor when the latter is energized for operation in either direction of rotation. A switch is manually operated to raise or lower the undercarriage and the movement is terminated on completion by limit switches which stop the motor and also release the clutch disc 72 which is then pressed into engagement by a spring 76 with the brake disc 80 to stop quickly the rotation of the gearing. The screw-shaft 41 and nut 101 are formed with helical grooves co-operating with balls 115 and shunt passages 111, 112 on the nut 101 are provided for the balls. In the event of mechanical or electrical failure of either the motor or the gearing, the nut 101 can be rotated manually through a flexible cable and a worm and wheel drive 175, 106, to move the casing 150 along the 'screwshaft 41 to actuate the undercarriage.