Dewatering travel time cam, dewatering timer, twin-tub washing machine and dewatering machine

The invention discloses a dewatering travel time cam, a dewatering timer, a twin-tub washing machine and a dewatering machine. The dewatering travel time cam comprises a sector portion, wherein a notch is formed in a cam flange adjacent to the sector portion, a protruding block is arranged on the portion, between the sector portion and the notch, of the cam flange, and the notch and the protruding block are in smooth connection. The dewatering timer comprises the dewatering travel time cam, a dewatering control spring leaf with a dewatering control contact point, a buzzing control spring leaf with a buzzing control contact point, and a power source spring leaf with a power source contact point and a protruding point. The protruding point presses the cam flange of the dewatering travel time cam; when the dewatering travel time cam rotates, the protruding point makes contact with concave and convex working surfaces of different regions of the dewatering travel time cam, and therefore the power source contact point and the dewatering control contact point can be connected or disconnected, and the dewatering control contact point and the buzzing control contact point can be connected or disconnected. A buzzer can be energized through the dewatering timer with the dewatering travel time cam during a certain period before dewatering movement ends, and the buzzer makes a sound to remind a user that dewatering movement is about to end.