| 摘要 |
679,473. Variable-speed gearing. M. & W. PATENTS, Ltd., and MILLER, A. A. May 9, 1950 [Feb. 10, 1949], No. 3681/49. Class 80 (ii). In a two-speed epicyclic gear in which the annulus 2 drives, the carrier 4 of planets 3 is driven, and the sun gear 1 either serves as a reaction member for a reduced drive or is clutched solid to the driving member for a direct drive the change is effected automatically in accordance with both torque and speed. Backward rotation of the reaction sun 1 is prevented a one-way brake 11, 12 and slight movement under the re-action torque acts through a screwthread connection 60 to control the engagement or disengagement of the direct drive clutch 53- 58 in conjunction with the effect of centrifugal masses 64 carried on member 55 secured for rotation with the sun gear 1. Thus at low torque the clutch 53-58 is engaged for direct drive and the masses 64 assist this engagement as the speed increases whilst when the torque increases the clutch slips and the centrifugal effect of the masses 64 decreases until the sun gear is held stationary by the one-way brake 11, 12. In another arrangement the clutch is radially acting and the centrifugal effect of the shoes themselves is utilised for engagement under control of a pin and cam slot connection with the reaction sun gear responsive to the reaction torque. A number of two-speed units as described may be arranged in series to operate in succession under different degrees of torque and speed. Specification 679,523 is referred to. |
