US Patent 10365494 Adjustment structure of a bridle

An adjustment structure of a bridle including a bridle, rotating shaft, and a knob is provided. The bridle has a rack. The rotating shaft has a first ring gear and a second ring gear both around an axis, wherein the first ring gear is coupled to the rack, such that the rotating shall moves along the bridle by rotating about the axis itself. The knob is rotated about the axis and moved along the axis to be movably coupled to the rotating shaft. The knob has a third ring gear to be engaged with or released from the second ring gear by the knob moving along the axis. When the third ring gear is engaged with the second ring gear, the knob is forced to drive the rotating shaft to rotate about the axis.