US Patent 11040647 Vehicle seat

A headrest is supported by an upper lateral member and a lower lateral member of a seat frame. A headrest stay is inserted through each of guide slots, both of which are formed in both the upper lateral member and the lower lateral member, and an extension wire is hooked on a lower end of the headrest stay. In a rear-collision, a seat back is retreated by a force received from a seated passenger, and a tension of the tension wire is accordingly loosened, which causes the headrest to be tilted forward by an urging force of tilt springs.