GB651798A - Improvements in and relating to electrical actuators for aircraft - Google Patents

Abstract

651,798. Screw - and - nut actuators. ENGLISH ELECTRIC CO., Ltd. Jan. 19, 1948, No. 1633. [Class 78 (iii)] [Also in Groups XXIV, XXXIII and XXXVII] A screw jack actuator is driven alternatively by a main and an auxiliary electric motor which operate respectively on two of the three main components-sun-wheel, planet-wheel carrier and annulus-of an epicyclic gear, the third component being geared to the mechanical part of the actuator. The main motor drives the sun-wheel 7 through a friction clutch and a speed-limiting device and since the annulus 19 cannot revolve, it being restrained by the braked auxiliary motor 22 and the gear train 15-19, the planet-wheel 6 rotates causing the carrier 5 to drive, through the gear train 4-3-2, a screw jack spindle 1 of the actuator. In an emergency the auxiliary motor 22 is energized together with its electromagnetic brake 21 and the electromagnetic brake of the main motor, normally free, is braked whilst the auxiliary motor, normally braked, rotates and drives, through a speed-limiting device 20 and the gear train 19-18-17, a pinion 16 meshing with internal teeth 15 on the annulus 9 causing the annulus to rotate in the needle bearings 10. As the sun-wheel 7 is held stationary by the main brake motor the planet-wheel 6 will rotate and be displaced taking the carrier 5 with it and applying to the spindle 1 substantially the same torque as normally applied by the main motor. In another embodiment, Fig. 2, Provisional Specification (not shown), the auxiliary motor drives the planet-wheel carrier and the annulus drives the screw jack spindle. A circuit diagram (see Group XXXVIT), is given in Fig. 3 (not shown) for a reversible motor and a unidirectional auxiliary motor having separate supplies.