Patent GB-604756-A (GB)
Title: Improvements in or relating to apparatus for driving aircraft accessories
IPC: B64D35/04
Filed: 1944-12-15
Abstract: 604,756. Variable-speed epicyclic gearing. STRATOS CORPORATION. Dec. 15, 1944, No. 25206. Convention date, Aug. 10, 1943. [Class 80 (ii)] [Also in Groups XXVI, XXVII and XXXIII] In a transmission mechanism of the differential gear type for driving counterrotating propellers from an engine shaft, an auxiliary shaft driving one or more accessories such. as a supercharger and cooling fan is coupled to the transmission by gearing such that the speed of the shaft is a predetermined function of the speeds of the two propellers. The speed of the shaft may be proportional to the difference in speeds of the two propellers or equal to the sum or difference of values proportional respectively to the speed of one and the other propeller. In one form, Figs. 1 and 2, variable pitch counter-rotating propellers 101, 102 are mounted on co-axial internal and external shafts 11, 17 and are driven from an engine shaft 100 by gearing comprising an internal ring-gear 2, mounted on a member 1, fixed to .the shaft 100, a central gear 9 fixed to the shaft 11, and satellite gears 3 mounted on axles 4, carried by a member 5- fixed to the shaft 17. An auxiliary shaft 16, which drives a supercharger 105 through bevel and epicyclic gearing is driven by another internal gear 8 carried by the member 1 and meshing with a second set of satellite gears 7 carried by the member 5, gears 7 also meshing with a central gear 12 fixed to a wheel 13 which carries an external gear 14 meshing with a gear 15 on the shaft 16. The speed of the shaft 16 is equal to the difference between quantities proportional respectively to the speeds of shafts 11 and 17, and the speed of the supercharger may, therefore be controlled by adjusting the pitch of either propeller. In a second form, Fig. 3, shafts 11, 17 are driven from the engine shaft 100 by a gear 23 fixed to the shaft 100 and meshing with satellite gears 25, a member 24 fixed to the shaft 11 and carrying the axles of the satellite gears, and an internal gear 28 in mesh with gears 25 and attached to a member 29 fixed to the shaft 17, Member 29 is integral with a member 30 carrying an internal gear 31 meshing with satellite gears 32, the axles of which are carried by a wheel 34 which carries a gear 35 driving a gear 15 on the shaft 16. The speed of the shaft 16 is equal to the difference between quantities proportional respectively to the speeds of the shaft 11 and engine shaft 100 and the supercharger speed is, therefore, adjustable by varying the pitch of propeller 101. The speed of the shaft 16 may also be expressed as a function of the speeds of the shafts 11 and 17. In both Figs. 2 and 3, the shaft 16 may drive a cooling air fan in parallel with the supercharger. In a third form, Fig. 4, the engine shaft 100 carries a bevel gear 43, meshing with satellite gears 47 carried by a member 46 secured to the shaft 11, and the shaft 17 carries a member 51 on which are mounted satellite gears 52 meshing with a gear 53 fixed to the crank-case. The members 46 and 51 carry crown-gears 70 and 71 meshing with a pinion 72 rotatable on a pin 73 which is slidable in an annular groove formed in a double gear 54, the latter being rotatable on the shaft 11, and meshing with the satellites 47, 52. The pin 73 is carried by an annular member 74 formed with an external gear 75 from which a drive is taken to the shaft 16 and a fan 61 by means of gearing 55, 57 and 55, 56, 58, 59, respectively. In this case, the speed of the shaft 16 is proportional to the difference in speeds of the propeller shafts. The Specification as open to inspection under Sect. 91 also describes a construction similar to that of Fig. 4, (see Fig. 4, Cancelled), in which the drive for the shaft 16 and fan 61 is taken directly from the double gear 54 and the speed of the shaft is proportional to the speed of the propeller shaft 17. The fixed vanes 64 of the fan are adjustable to vary the division of torque between the supercharger and fan. This subject-matter does not appear in the Specification as accepted.