GB671076A - Improvements in speed governors and their application to helicopters - Google Patents

Abstract

671,076. Differential speed-governors. SOC. NATIONALE DE CONSTRUCTIONS AERONAUTIQUES DU SUD-OUEST. Oct. 11, 1949 [Oct. 14, 1948], No. 26130/49. Class 57 [Also in Groups XXIV and XXXIII] In a differential speed-governor comprising a sun gear 2 connected to a constant reference speed source 46, a sun gear 1 connected through a shaft 37 with the device whose speed is to be controlled and a planet case 4 connected to the speed control member of the engine driving the device, the connection between the planet case and the control member comprises two gear trains 40, 41 having different ratios which are alternately brought into action by clutches 18, 19 when either the velocity'or acceleration of the planet case changes sign, the lower gear ratio, constituting the higher governor power, being coupled when the velocity and acceleration are of the same sign. This arrangement causes damping of the oscillations of the controlled speed. The reference speed may be attained from the controlled speed source through gears 127, 38, 128, 21 and a constant speed centrifugal clutch 46 (see Group XXIV) which has provision to compensate for changes in its output torque. Acceleration and speed direction detectors 47 comprise independent discs driven from a common shaft 7 and carrying electrical contacts operable to energize the electromagnetic clutches 18, 19. A clutch 43, (not shown), operable by a lever 45 disconnects the governor when the speed is to be adjusted manually by a lever 44 and simultaneously the speed setting of the constant speed clutch may be adjusted by a gear 36 through a clutch which is also operated by lever 45. The latter clutch may also be operated independently by a solenoid 85 whilst clutch 43 may be operated by a solenoid 84. The governor may transmit to the engine through a servomotor, and may be used for synchronising a number of engines one of which may provide the reference speed. The governor may also be used for controlling the blade pitch of a helicopter rotor (see Group XXXIII).