The invention relates to a blocked-grass lower-poking and upper-
cutting mechanism for cleaning a grass discharging passage of a hand
mower. According to the blocked-grass lower-poking and upper-
cutting mechanism, a lower poking mechanism is mounted on a rear shaft of the bottom of the
mower, and meanwhile, an upper
cutting mechanism is mounted at a grass discharging port of the grass discharging passage of the
mower; the lower poking mechanism contains grass discharging blades (j1) and direction-changing bevel gears (j2), the rotating direction of a third direction-changing
bevel gear is reverse to that of a first direction-changing
bevel gear and that of the rear shaft, and thus, the rotating and direction changing of the grass discharging blades (j1), which are connected with the third direction-changing
bevel gear and sleeve the rear shaft, are achieved; and the upper cutting mechanism contains upper cutting blades (j3) and a belt-
pulley belt (j4), and a rotating shaft of the upper cutting blades (j3) is driven by the belt-
pulley belt (j4). The direction-changing bevel gears are Klingen-Berg cycloidal-tooth hypoid gears. At least one of the upper cutting blades (j3) of the upper cutting mechanism of the blocked-grass lower-poking and upper-cutting mechanism for cleaning the grass discharging passage of the hand mower has a bent segment, and a curve of the bent segment is a
logarithmic spiral which has the characteristic that pressure angles are equal everywhere.