Seat headrest rotation freely-adjusting device

The utility model discloses a seat headrest rotation freely-adjusting device. The seat headrest rotation freely-adjusting device comprises two headrest rods, an 'n'-shaped bent pipe, a rotary shaft, a side supporting plate, a limiting bracket, a rotary shaft return spring, an outer side plate, a supporting plate, a lower toothed plate, an upper toothed plate and a lower toothed plate return spring. When the seat headrest rotation freely-adjusting device is in an initial state, the upper toothed plate and the lower toothed plate are meshed with each other, a horizontal guide column is positioned at the front end of an arc surface of the top part of a guide window, the bent pipe is forwardly pushed to drive the upper toothed plate to move forwardly relative to the lower toothed plate, the lower toothed plate is reset under the action of the lower toothed plate return spring after the upper toothed plate moves by the length of each tooth, and then is meshed with a rear tooth of the upper toothed plate until the horizontal guide column is positioned at the rear end of the arc surface of the top part of the guide window, and the upper toothed plate and the lower toothed plate are still meshed with each other at the moment; and the bent pipe is forwardly pushed continuously, the horizontal guide column moves downwardly in the guide window along a rear-end slope, the upper toothed plate is separated from the lower toothed plate, and the bent pipe automatically returns to an initial state under the action of the rotary shaft return spring. The seat headrest rotation freely-adjusting device has the advantage of being capable of adjusting optional angles in certain ranges.