Mower drive with V=belt tension roller

摘要

The tension roller (19) acting on the pulling strand (21) of the belt (18) is mounted on one arm (22) of a two-arm lever (23) whose second arm (25) is engaged by a tensile spring (26). A second tension roller (20) acts on the return strand (27), can move and/or slide in relation to this strand and is rotatably mounted on swivel lever (28). The two rollers are joined by the tensile spring (26) as fixed between lever arm (22) and swivel lever (28) so that the spring holds the toggle lever (23) in its tension position where this lever (23) adjoins an end-stop. The spring converges the two rollers to tension the belt, using screw (29) to vary the tension obtained. The spring holds the lever (23) beyond dead centre in the tension position. Should the cuttings conveyor jam with resultant overload on the drive, the strand tries to straighten the belt out and in so doing forces roller as arrowed (31) so the lever swings beyond dead centre as arrowed (32) thus relaxing the belt and cutting out the drive so the drive pulley can turn without overheating.