Crank lock

The invention relates to a crank lock which is characterized in that a guide connecting structure of a lock cylinder protective cover guide arranged on a handle comprises a pivoting foot, a guide foot and guide grooves formed in the two transverse sides of the handle, a rocker arm mounting seat is arranged on the back side of the handle, a guide rocker arm is pivoted on the rocker arm mounting seat, and the guide rocker arm swings in the direction corresponding to the length direction of the handle; the extending direction of the guide groove is matched with the swinging direction of the guide rocker arm, a guide foot on the lock cylinder protection cover is slidably and rotatably supported in the guide groove, an avoiding channel leading to the rocker arm installation base is formed in the top face of the handle, a pivot joint foot of the lock cylinder protection cover extends into the avoiding channel and is hinged to the top end of the guide rocker arm, and the guide rocker arm is provided with a vertical