Patent GB-1115010-A (GB)
Title: Selective drive device
Inventor: KING PETER
IPC: G05G9/00
Filed: 1966-03-15
Abstract: 1,115,010. Clutch control; toothed gearing. ROLLS-ROYCE Ltd. 15 March, 1966, No. 11392/66. Headings F2L and F2Q. [Also in Division F1] A drive connection is selectively established between an input shaft 36 and any one of a number of output shafts 58, via a sun gear 38 on the input shaft, a planet gear 40 on a rotatable carrier 42, and an output gear 56 on the output shaft. An annular gear 44 has gear teeth 46 meshing with the planet gear 40, and external splines 50. A stop member 52, carried on the armature of a solenoid 54, engages either the splines 50, or splines 48 on the carrier 42. When the solenoid is energized, the stop member engages splines 50 to hold the annular gear 44 against rotation, and rotation of the input shaft 36 rotates the carrier 42, processing the planet gear 40 about the sun gear, and presenting the planet gear to each output gear 56 in turn. On de-energizing the solenoid, the stop means engages splines 48 to hold the carrier against rotation, and, if the planet gear 40 is in mesh with an output gear 56, rotation of the input shaft 36 effects rotation of the respective driven shaft 58. A D.C. control bridge circuit. Fig. 6 (not shown), is provided for three output shafts, and includes a selective switching device controlled by the carrier 42, to ensure, that the carrier is stopped only when the planet gear 40 is in mesh with an output gear 56. Two adjacent arms of the bridge are provided with standard resistances (r), (R) and a third arm with a standard resistance (ro) and three reference resistances (ra-rc), one of which may be connected selectively in parallel with resistance (ro). The remaining arm contains four resistances (Ro), (Ra-Rc). Any one of the resistances (Ra-Rc) may be connected selectively in parallel with resistance (Ro), and all four resistances are controlled by cam-operated switches (63), (62a-62c). The switches (62a- 62c), Fig. 5 (not shown), have actuating elements which co-operate with a cam surface (66) on the carrier (42), so that the respective switch is closed once only in each complete revolution of the carrier. The switch (63) is closed each time one of the switches (62a-62c) is closed. The resistances (ra-rc), (ro), and (Ra-Rc), (Ro) are chosen so that ro balances Ro, ra balances Ra &c. When an output shaft a is desired to be driven, the resistance (ra) is switched into the circuit, and the out-ofbalance current to the circuit energizes the solenoid, driving its armature and the stop member 52 into engagement with splines 50 on the annular gear 44. The armature also carries a contact (80) which completes the circuit of an electric motor 26 to drive the input shaft 36 and rotate the carrier 42 to present the planet gear 40 to each output shaft 58 in turn. When the planet gear meshes with the output gear 56 of shaft a, the resistances Ra, Ro are connected in parallel in the bridge circuit, and the bridge is balanced. The solenoid is thus de-energized and the armature withdrawn, breaking the electric motor circuit to stop the shaft 36, and moving the stop 52 into engagement with splines 48 on the. carrier 42. On depressing one of two push-buttons (P R ), (P L ), depending on the direction of rotation required, the electric motor circuit is completed, and the output shaft a is driven. An electrically operated revolution counter (91) is connected in the bridge circuit. The invention is described applied to the fuel control unit (18), Fig. 1 (not shown), of a gas turbine jet propulsion engine (10).