Deadman control and blade clutch for power rotary lawn mowers

A lawn mower comprising a blade housing, a cutter blade supported for rotation by and within said blade housing, a driven pulley drivingly connected to said cutter blade for rotation of the latter in response to rotation of the former, a drive pulley adapted to be rotatably driven by a source of power, an endless belt reeved around said drive pulley and said driven pulley, an arm, an idler pulley mounted for rotation on said arm, means mounting said arm for movement relative to a neutral position with said idler pulley disengaged from said belt, means resiliently urging said arm from said neutral position so as to engage said idler pulley with said belt to remove slack therefrom, a control linkage movable between a drive position and a neutral position, means biasing said control linkage toward said neutral position, and means connecting said linkage and said arm for displacing said arm to said neutral position against the action of said arm urging means when said control linkage is in said neutral position and for permitting movement of said arm, under the influence of said arm urging means and independently of said control linkage biasing means, from said arm neutral position so as to engage said belt to remove slack therefrom when said control linkage is in said drive position.