GB1238121A - - Google Patents

Abstract

1,238,121. Variable-speed gear; controlling clutches; chain tensioners. ALLIS-CHALMERS MFG. CO. 26 Sept., 1969 [1 Oct., 1968], No. 47454/69. Headings F2D, F2L and F2Q. A steplessly-variable change-speed gear for tractors, lawn-mowers and swathers &c. comprises a three-element train 47 in which the ring and sun gears 50, 100 are directly and variably driven respectively, in opposite dierctions, via a constant speed V-belt gear 31 and a variable speed expanding pulley gear 19 from an engine driven input shaft 6, the planet carrier 67 driving, via reduction gearing 65, 71 and 72, 79 an output shaft 82 such that stepless ratio variation of the output shaft 82 may be effected in either direction of rotation from a neutral, i.e. stationary condition of the planet carrier 67. As shown, the input shaft 6 drives, via bevel gears 8, 7, both belt drives 31, 19 from a common shaft 3, the constant speed driven pulley 30 being connected to the ring gear 50 via a countershaft gear arrangement 110, 57, 51 which provides a gear reduction and reverse drive of the ring gears 50 relative to the sun 100 which is directly driven from the variable speed expanding driven pulley 21. In an alternative arrangement the ring gear 50 may be directly driven from the constant speed driven pulley 30 the drive pulley 10 of which is driven by a shaft 150 of a second bevel 111 meshing the bevel 8 to provide the gear reduction and reverse drive of the ring gear 50 as before. The expanding pulley gear 19 is manually varied to control forward drive through neutral to reverse drive by a lever 12 which is pivoted at 13 and simultaneously actuates through adjustable linkage 14, 15, 16, 26, 24 one axially movable pulley flange half 17, 21 of each of the driving and driven pulleys 9, 21. The V-belt drives 31, 19 are tensioned by idler pulleys 85, 91 the latter of which is connected via a bell-crank 90 and linkage 88, 89, 92 to a belt tension control mechanism 94 whereby an increase in tension of the variable speed expanding pulley belt 19, due to regenerative torque created via the planetary gear during reverse drive of the vehicle (i.e. when the transmission shifts from forward through neutral to reverse), automatically places a greater tension in the device 94, and both springs in the device compress to provide for the increased tension of the belt 19. A brake band 97, having a brake lining 175, is connected via a rod 96 to the automatic tensioner linkage and serves to engage a brake drum 174 on an intermediate shaft 73 of the output reduction gear train such that engagement of the brake bond 97 via a brake pedal (not shown) simultaneously overrides and releases the automatic belt tensioner 94, and vice-versa, to function as a stopping and starting control for the vehicle.