Patent GB-608756-A (GB)
Title: Improvements in control mechanisms for wing flaps and hyper-lifting devices for aircraft
IPC: B64C13/00
Filed: 1941-02-15
Abstract: 608,756. Controlling aircraft. AIR-EQUIPEMENT. Feb. 15, 1941, No. 2086. Convention date, Dec. 13, 1939. [Class 4] [Also in Groups XXX and XXXVIII] Control mechanism for aircraft wing flaps comprises a motor driving through reduction gear and a torque limiting device, one or more movable control elements coupled to the flaps, the part of the mechanism between the motor and the torque limiting device being practically irreversible, the remaining part of the mechanism being reversible. A reversible electro-motor may be used and limit switches provided to stop the motor when the control element has reached the limit of its movement, or, by adjustment of the switches, at any intermediate point. In one form a control switch having a follow-up device is used. Fig. 1 shows an electro-motor 14, which drives through multiple reduction-gear a sun wheel 37 of an epicyclic gear. The planet wheels 38 of this gear are carried by a flange on a shaft 10 and gear with an internallytoothed wheel 41 clutched to the casing by a multiple plate clutch 43. The plates are pressed together by springs 48 and the pressure is adjusted by a screwed ring 51 which can be rotated by a pinion 53 on a shaft 54 extending to the outside of the casing. The shaft 10 has a pinion 9 gearing with a rack 2 connected to the wing flaps. Excessive gusts on the wing flaps cause the clutch 43 to slip without stalling the motor 14. The shaft 10 may have two pinions engaging two racks set at an angle to one another corresponding to planes set at a dihedral angle. In another form, Fig. 11, the reducing gear drives a bevel wheel 33 coupled by an adjustable plate clutch 36, 38 to a transverse rotary shaft 1 extending to the outside of the casing and coupled to the flap by internally threaded end portions 4. Fig. 4 shows a switch 58, which is actuated by a lever 61, which is engaged by a flange 62 on the rack at the extreme end of the stroke so as to stop the motor. A similar switch is provided for operation by the opposite end of the rack. An additional switch actuated by a longer lever 67 may be put into circuit if it is desired to stop the movement of the rack earlier in its stroke. Alternatively, the switch and its actuating lever may be movable parallel to the rack so that the switch is opened at any desired length of stroke. Fig. 6 shows a modified switch comprising a casing 80, movable by a lever 84 in a fixed sleeve 81 on the gear casing. The casing carries two pairs of contacts 88, 89 adapted to be bridged by a member 87 to start the motor in one direction or the other. The member 87 is carried by a rod 86, urged by a spring 91 against the bottom of a cam groove 92 in the rack 2, the motor being stopped when the cam groove moves the member clear of the contacts. Fig. 8 shows a control device in which two switches 112, 113 co-operate with two cam segments 99, 100 carried by a pulley connected by cables 98 to the rack. The switches are carried by an arm 104 pivoted about the axle of the pulley and are normally both off. When the arm 104 is moved a switch is closed to start the motor in the appropriate direction and the cam segments follow-up the arm until the " off " position is again reached.