GB615089A - Improvements in or relating to variable-speed gearing - Google Patents

Abstract

615,089. Change-speed gearing. BIRMING- HAM SMALL ARMS CO., Ltd., and FLETCHER, J. Aug. 24, 1946, No. 25348. [Class 80 (ii)] A vehicle change-speed gear giving a wide range of gear ratios comprises an epicyclic gear train mounted on a mainshaft 3 between freely mounted pinions 15, 17 meshing pinions 19, 21 respectively splined to a driven shaft 5. Planet pinions 29 engage a sun wheel 31 fixed to the shaft 3 and internal teeth on an annulus 33. Ratchet teeth 49 formed on the circumference of the annulus 33 are engaged by spring loaded pawls pivotally mounted on the casing 1, so that in the driving condition the annulus is held stationary, but may rotate in the opposite direction to facilitate free-wheeling. A chain connects sprockets 9, 11, secured to shafts 7, 3, respectively and a clutch (not shown) is incorporated between the shaft 7 and driving shaft 13. A sprocket 25 secured to the shaft 5 is chain connected to the vehicle wheels. As shown in the Figure, the gears are in the neutral position. To engage top gear, the pinion 15 is moved so that dog teeth 37 thereon engage internal dog teeth 39 on a sleeve 41 keyed to the shaft 3. On engagement of the gear teeth of the pinion 15 with adjacent internal dog teeth 35 on the planet carrier 27, the drive is transmitted through the sun wheel 31, planet pinions 29, planet carrier 27 and pinions 15, 19, thus effecting low gear condition. Similarly when the pinion 17 is clutched to the planet carrier by engagement of dog teeth 43 with teeth 45, the drive is transmitted through the epicyclic train and pinions 17, 21 giving a medium gear.