Patent ID: 8141945

Claim:
A vehicle seat comprising: a first sensor that is disposed inside a seat back and is capable of detecting a back-side collision of a vehicle when pressed by a body of a sitting passenger; and a second sensor that is capable of detecting the back-side collision of the vehicle based on a longitudinal acceleration of the vehicle, wherein the first sensor and the second sensor are respectively oppositely disposed in a widthwise direction of the vehicle seat, wherein a head rest is constructed to be moved forwardly based on detection signals when both of the first and second sensors detect the back-side collision of the vehicle, wherein the first sensor disposed inside the seat back comprises a position detection sensor that is actuated when pressed by the body of the sitting passenger, and wherein a biasing force for maintaining the first sensor in an inactive condition is set to a force that is required to restore the first sensor from an active condition to the inactive condition, wherein the position detection sensor comprises a rotation angle detection sensor that is attached to one of right and left sides of a back frame of the seat back, wherein one end of a rod is connected to the position detection sensor, wherein an other end of the rod is connected to the other of the right and left sides of the back frame, and wherein when the rod is pressed by the body of the sitting passenger at the time of the back-side collision of the vehicle, a rotational force can be applied to the rotation angle detection sensor, so that the back-side collision of the vehicle can be detected.