Abstract: A cutting blade assembly for a lawn mower is provided with mechanism for prestressing the blade to lessen vibration during use and also for adjusting the blade so as to accurately position and align the blade relative to the associated blade housing so that the blade operates in a horizontal plane. This prestressing and adjusting mechanism may also be employed to compensate for any misalignment in the mounting of the blade spindle relative to the blade housing. In one specific embodiment in which the blade is bolted to a blade support bar which, in turn, is fixed to a vertical spindle mounted centrally to the blade housing, the prestressing and adjusting mechanism is achieved by pressure-applying bolts or screws threaded through the blade support bar on opposite sides of the spindle so as to be engageable with the blade. Advancement of the screws serves to deflect the blade downwardly to prestress the blade and/or to position the blade in a desired horizontal plane.

Abstract: A riding mower having an improved blade housing and blade assembly for generating exceedingly high vacuum under the blade housing for facilitating cutting, conveyance and discharge of grass clippings into a two-wheeled cart which trails the mower through means of a hitch. Grass clippings leave and are conveyed from the blade housing to the cart in a straight line through a conduit including telescoping chutes which permit the conduit to elongate or retract to accommodate change in lengths between the blade housing and the cart during operation. The cart has an open top covered by a canopy including a flexible front wall portion which receives an elbow chute to which one of the telescoping discharge chutes is attached.