Lawn mower
A lawn mower includes a hollow shaft, a cutter blade, flaps, a belt type continuously variable transmission, and a transmission mechanism. The cutter blade extends along a horizontal line which is perpendicular to the hollow shaft. The flaps are provided for the cutter blade. Each of the flaps has a flap angle changeable along the horizontal line. A control force converter unit of the belt type continuously variable transmission converts a displacement force of the movable sheave relative to the fixed sheave in an axial direction into a control force that controls the flap angle of the flaps. The transmission mechanism is accommodated inside the hollow shaft, and transmits the control force to the flaps.
1. A lawn mower comprising:
a housing including an opened bottom;
a rotation shaft extending in a vertical direction of the housing and having a lower end positioned within the housing;
a cutter blade provided for the rotation shaft, and accommodated in the housing; and
a belt type continuously variable transmission provided in a working power transmission system from a drive source to the rotation shaft, the belt type continuously variable transmission capable of changing a reduction ratio of a driven pulley to a drive pulley in a continuous manner,
wherein the cutter blade extends along a horizontal line which is perpendicular to the rotation shaft;
the driven pulley includes a fixed sheave provided for the rotation shaft, a movable sheave which is displaceable relative to the fixed sheave in an axial direction, and a torque cam mechanism configured to partially convert a rotation force applied to the movable sheave into a thrust that presses a side surface of a V-belt; and
the lawn mower further comprises:
a flap provided for at least part of the cutter blade, the flap having a flap angle changeable along the horizontal line;
a control force converter unit configured to convert a displacement force of the movable sheave relative to the fixed sheave in the axial direction into a control force that controls the flap angle of the flap; and
a transmission mechanism configured to transmit the control force of the control force converter unit to the flap, and
wherein the rotation shaft comprises a hollow shaft; and
the transmission mechanism is accommodated inside the hollow shaft.
2. The lawn mower according to claim 1 ,
wherein the transmission mechanism comprises:
a control shaft fitted into the hollow shaft, the control shaft being slidable in the axial direction;
a converter mechanism accommodated inside the hollow shaft in a manner that sliding movement of the control shaft can be converted into movement to change the flap angle of the flap;
a lower end of the control shaft is coupled to the flap through the converter mechanism; and
a conversion shaft of the control force converter unit is combined with an upper end of the control shaft in a manner that the control shaft can be driven in a sliding manner.
3. The lawn mower according to claim 2 , wherein the converter mechanism comprises a pin extending radially outside from the lower end of the control shaft and a cam including a cam surface which can contact the pin;
the cam is supported by the hollow shaft rotatably about a swing center of the flap and provided at the flap; and
the cam surface comprises a cam groove capable of converting sliding movement of the pin which is displaced in a sliding manner together with the control shaft into rotation movement of the cam.
4. The lawn mower according to claim 1 , further including a lower cutter blade positioned below the cutter blade; and
the lower cutter blade comprises a fixed blade fixed to the hollow shaft.