GB673553A - Improvements in or relating to variable speed transmissions - Google Patents

Abstract

673,553. Hydromechanical variable-speed gear. WINDFIELDS (1946), Ltd. June 9, 1950 [June 23, 1949], No. 14491/50. Class 80 (ii). A fluid torque-converter of the kind (e.g. as described in Specification 548,044) wherein the forwardly-releasable reactor 10 is so designed as to become an efficient fluid-coupling runner after torque-conversion ceases; drives an output shaft 13, carrying, a sun 17, through a sun 15, fast to its turbine 6 and stepped planets 28 on a carrier 18, secured to its reactor 10, prevented from reverse rotation by a one-way detent 24 and connected with its impeller 5 on the input shaft 1 by a centrifugal expanding-shoe friction clutch 31, the carrier 18 being rotated by the reactor of the converter when the latter acts as a coupling so as to cause engagement of the clutch 31, which eventually provides a splittorque one-to-one drive through a mechanical path including the impeller 5, centrifugal clutch 31, planets 28 and output sun 17, together with a fluid path through the converter (now acting as a coupling), including the turbine 6, its sun 15 and planets 28. The clutch comprises centrifugal shoes 31 pivoted at one end on pins 30 on the carrier 18, and connected at their other ends by cranked links 36, Fig. 3, to a drum 34 which is urged circumferentially relative to the carrier 18, in a direction to oppose the centrifugal force on the clutch shoes, by coil springs 35 compressed in registering tangential slots in the carrier 18 and drum 34. The centrifugal clutch 31 can be disabled at any time for enforcing a downshift by applying a brake-band 37 manually to the drum 34. Drive passes from the output shaft 13 to the final driven shaft R3 through a bevel reversegear in which a freely-mounted planet-carrier R7 is clutched at R11 to the fixed casing for reverse, or to an input bevel at R10 for solid forward drive, by axial movement of a selectorsleeve R18, which tilts a pair of dogs R17, each rockable radially in a slot R21 in the carrier R7, to engage either of the clutch-teeth R10, R11, engagement being facilitated by applying an anti-drag brake R16 to the input shaft 13 of the reverse gear.