Patent GB-439828-A (GB)
Title: Improvements in or relating to variable speed power transmission apparatus
IPC: F16H61/02
Filed: 1934-06-16
Abstract: 439,828. Variable-speed epicyclic gearing. FREEBORN POWER CONVERTERS, Ltd., FREEBORN, J. E., DEGENHARDT, W. R., and FRAINE, A. F. DE, 49, Moorgate, London. June 16, 1934, Nos. 17885/34, 21415/34, and 1420 /35. [Class 80 (ii)] Variable-speed gearing comprises an epicyclic train having one member kept by a detent from turning backwards on geared drive, the train being adapted alternatively to be clutched solid and restored to geared drive under the joint control of speed-responsive and torque-responsive elements which are directly connected together and mutually opposed at all times so that the speed-responsive element supplies the sole restoring force for the torque-responsive element, and vice versa. A simple form showing the balance between speed and torque is shown schematically in Fig. 6. A driving disc 40 carries a centrifugal lever 42 a heel 44 of which lever initially passes on the drive to a lug 46 on a driven plate 48. As speed predominates, the plate 48 is thrust round relatively leftwards against the resisting torque, upon which ball-ended toggle links 50 draw the plates 48 and 40 together thereby engaging a plate clutch and disabling or clutching solid the epicyclic train. As torque predominates, the lug 46 collapses the weighted lever 42 so that the tension in the toggles 50 vanishes, the plate clutch is opened, and geared drive on reduced speed is resumed, the detent functioning to increase the torque. In a practical form shown in Fig. 7, 158, 160, 162, 164 is a train with stepped planets in which the planet-carrier 172 is kept from rotating backwards by a resilient detent 174, Fig. 8, when the gearing is operative to drive a hollow shaft 166 on reduced speed. A manual clutch 124 connects a driving-shaft 116 to a flange 146 which turns clockwise of Fig. 8 and through collapsed centrifugal levers 152, angle levers 188, a flange 154, and sleeve 156 drives the first gear 158 of the train. Since the carrier 172 cannot yield rearwardly, the gearing operates, yielding reduced speed. The speed effect tending to expand the levers 152 through the lever heels 150 opposes the driving torque on the flange 146. When the speed effect predominates, the flange 146 is thrust back against the drive and the weighted levers 152 expanding thrust the angle levers 188 axially of Fig. 7 so as to engage a plate clutch 180 connecting the sleeve 156 to bolts 186 on the planet-carrier 172. The train is thus clutched solid on high speed, the detent 174 overrunning. Immediately the torque effect predominates, change back to reduced speed takes place. Driven plates 140 of the main clutch 124 are planetary as described in Specification 426,407. In Fig. 9 is shown an epicyclic train in which an annulus 216 drives, a planet carrier 222 is driven, and a sun 250 is kept from turning backwards on geared drive by a detent pawl 254, Fig. 10, engaging a detent disc 252. A main clutch 206 controlled by a centrifugal lever 194 pivoted on a driving-disc 192 picks up the drive automatically to the annulus 216. The carrier 222 is connected through a disc train clutch 245 to a member 260 adapted to be engaged by a forward and reverse driven clutch 262 sliding on a driven shaft 226. There is a non-epicyclic reversing train at R. The balancer which balances speed against torque is shown in Fig. 10 at 228, 234, 242 and is as described with reference to Fig. 8. The angle lever 242 which engages the train clutch 245 to disable the train is shown in Fig. 9. The pawl 254, Fig. 10, is rendered noiseless by flaps 284 which engage lightly over the sides of the detent disc 252. The overrunning disc lifts and holds the pawl clear. Specifications 349,492 and 377,733 also are referred to.