Blade assembly, power head and lawn mower

A power head, comprising:

• a housing having at least one external air inlet;
• a cover, arranged on the housing, and forming a first cavity with the housing;
• a control assembly, arranged on the housing, and the cover covering the control assembly;
• at least one internal air inlet, arranged on the housing, and arranged at a side edge of the control assembly;
• at least one air guiding plate, arranged on the housing, and forming a second cavity with the control assembly;
• and
• a driving assembly, arranged at a bottom of the housing, having an air outlet, and forming a third cavity with the air guiding plate;
• wherein cooling air flow enters the first cavity through the external air inlet, and enters the second cavity and the third cavity through the internal air inlet to flow out through the air outlet.

A lawn mower, comprising:

• a chassis, two ends of a bottom of the chassis being provided with front wheels and rear wheels respectively;
• a driving assembly, mounted on the chassis;
• a blade assembly, mounted on the bottom of the chassis and connected with the driving assembly;
• and
• a handle folding mechanism, mounted on the chassis, and including:
• a handle mounting base, fixed to the chassis,
• a limiting plate, mounted on the handle mounting base and provided with a plurality of limiting structures,
• a handle, an end of the handle being rotatably connected with the limiting plate, and the handle comprising a first handle and a second handle,
• a cross rod, mounted between the handles, and
• a limiting assembly, located in the handle, and the cross rod being capable of driving the limiting assembly to move to enable the handle to be capable of being fixed at different positions of the limiting plate.