Abstract: A variable speed drive for a riding lawn mower or the like has a double pulley variable speed sheave assembly coupled between a driving pulley and a driven pulley by first and second V-belts, respectively. The sheave assembly is carried at one end of a bell crank which is centrally pivoted to one end of a pivot arm. The pivot arm is pivotally connected to the vehicle frame and is biased to urge the sheave assembly toward an operating position with the belts under driving tension. A mechanical control linkage is connected to the other end of the bell crank, and is operable to shift the sheave assembly with respect to the driving and driven pulley to alter the sheave assembly drive ratio in a manner such that belt tension varies with variations in operating speed. The control linkage is operable to move the sheave assembly between a stopped position with both belts declutched and a range of low to high speed operating positions, and is springably biased to urge the sheave assembly toward said stopped position.

Abstract: A variable speed drive for a riding lawn mower or the like has a double pulley variable speed sheave assembly coupled between a driving pulley and a driven pulley by first and second V-belts, respectively. A mechanical control linkage is operable to shift the sheave assembly along the cam profile of a cam arm from a stopped position with both belts declutched to a range of low to high speed positions with the belts drivingly engaged. Said control linkage is springably biased to urge the sheave assembly toward the stopped position. The cam arm is also springably biased generally away from the driving and driven pulleys to maintain the belts under driving tension throughout the range of low to high speed positions in a manner such that belt tension varies with variations in operating speed.

Abstract: A variable speed drive for a riding lawn mower or the like has a double pulley variable speed sheave assembly coupled between a driving pulley and a driven pulley by first and second V-belts, respectively. The sheave assembly is carried on a pivot arm pivotally mounted on a frame for the vehicle. A mechanical control linkage connected to the pivot arm is operable to shift the sheave assembly with respect to the driving and driven pulleys from a stopped position with both belts declutched through a range of low to high speed drive positions with the belts drivingly engaged. An idler pulley is carried on a spring lever assembly for engaging and variably tensioning one of the belts throughout said range of speed positions to place the belts under variable driving tension in accordance with operating speed.