GB308301A - Improvements in or relating to driving and clutching devices for rotary air compressors of aviation engines - Google Patents

Abstract

308,301. Farman, H., aud Farman, M., (trading as Farman, H. et M.), (Assignees of Waseige, C. R.). March 21, 1928, [Convention date]. Variable-speed epicyclic gearing.-A compressor for supplying combustible mixture to an internal-combustion engine used on aircraft is driven at one speed at high altitudes and at a lower speed at low altitudes. The high speed drive is through a friction clutch 4, 9, 10, Fig. 1, and an epicyclic train on to a pinion 43 on the compressor-rotor shaft. The epicyclic train comprises either a fixed annulus 42 and planet spur pinions 41 or a fixed bevel wheel 52, Fig. 3, and planetary gear consisting of pairs of bevel wheels 51 on spindles journaled in bearings carried by the driven member 9 of the clutch. The clutch is of the kind described in Specification 288,173; the driving member of the clutch consists of a plate 4, carried on a hollow spindle 5 keyed to an extension 3 of the crank shaft. The plate 4 lies between two friction surfaces one carried by the driven member 9 of the clutch, the other by a plate 10 keyed to the member 9. Weighted levers 11 on a disc 7 are lightly pressed by springs 15 against the plate 10, and under the action of centrifugal force close the clutch; it is opened by a fork 19 moving a sleeve 18, and thereby displacing levers 16 which bear on the projecting ends of the weighted levers 11. With the clutch open the low speed drive can take effect. In one form this consists of an internal ratchet wheel 54, Figs. 4 and 5, formed on the driving member 4 of the clutch and spring-pressed weighted pawls 55 carried by a ring 57 keyed to the pinion 43 on the compressor shaft. A direct drive is .thereby obtained; when the high speed drive is used this ratchet clutch at first over-runs and then the weighted ends of the pawls move the pawls out of gear. In the form shown in Fig. 1 a similar ratchet clutch is used, with an epicyclic speed-multiplying train; this comprises a fixed annulus 65, planetary pinions 64 carried by the driving member 4 of the clutch, and a sun pinion whose interior forms the ratchet. In a modification of this last arrangement the ratchet clutch is disposed between a fixed part of the casing and a sleeve which carries the annulus 65.