Head rest for vehicle seat

A head rest device for a vehicle seat comprising:

• a stay member attached to an upper portion of a seat back of a vehicle seat and supporting a head rest, the stay member including at least one stay shaft extending downwardly from the head rest;
• a position adjusting device disposed in the seat back for adjusting a position of the head rest relative to the seat back, the position adjusting device including a drive motor, a threaded drive shaft operatively connected to and extending from the drive motor, a nut member threadably engaging the drive shaft and vertically movable along the drive shaft, a movable member secured to the nut member and vertically movable with the nut member, and a guide member for guiding the vertical movement of the movable member, the drive shaft and the guide member being disposed substantially parallel to one another and being spaced apart from one another in a plane extending in a lateral direction of the seat back;
• each of the stay shafts of the stay member including a curved longitudinal intermediate portion, and the guide member having a pair of guide holes for slidably receiving the stay shafts, each of the guide holes having a bending portion bent to correspond to the curved longitudinal intermediate portion of one of the stay shafts.

A head rest device for a vehicle seat comprising:

• a stay member attached to an upper portion of a seat back of a vehicle seat and supporting a head rest, the stay member including at least one stay shaft extending downwardly from the head rest;
• a position adjusting device disposed in the seat back for adjusting a position of the head rest relative to the seat back, the position adjusting device including a drive motor, a threaded drive shaft operatively connected to and extending from the drive motor, a nut member threadably engaging the drive shaft and vertically movable along the drive shaft, a movable member secured to the nut member and vertically movable with the nut member, and a guide member for guiding the vertical movement of the movable member, the drive shaft and the guide member being disposed substantially parallel to one another and being spaced apart from one another in a plane extending in a lateral direction of the seat back;
• the guide member being a plate member, and the movable member including a slidable portion having an opening that receives the plate member, the slidable portion including two oppositely positioned first projections extending from an inner surface of the slidable portion to engage the plate member.

A head rest device for a vehicle seat comprising:

• a stay member attached to an upper portion of a seat back of a vehicle seat and supporting a head rest, the stay member including at least one stay shaft extending downwardly from the head rest;
• a position adjusting device disposed in the seat back for adjusting a position of the head rest relative to the seat back, the position adjusting device including a drive motor, a threaded drive shaft operatively connected to and extending from the drive motor, a nut member threadably engaging the drive shaft and vertically movable along the drive shaft, a movable member secured to the nut member and vertically movable with the nut member, and a guide member for guiding the vertical movement of the movable member, the drive shaft and the guide member being disposed substantially parallel to one another and being spaced apart from one another in a plane extending in a lateral direction of the seat back;
• said movable member including a first sliding portion slidably contacting the guide member under operation in which said movable member receives a load below a predetermined load level, and a second sliding portion slidably contacting the guide member only when the movable member receives a load larger than the predetermined load level.

A head rest device for a vehicle seat comprising:

• a stay member attached to an upper portion of a seat back of a vehicle seat and supporting a head rest, the stay member including at least one stay shaft extending downwardly from the head rest;
• a position adjusting device disposed in the seat back for adjusting a position of the head rest relative to the seat back, the position adjusting device including a drive motor, a threaded drive shaft operatively connected to and extending from the drive motor, a nut member threadably engaging the drive shaft and vertically movable along the drive shaft, a movable member secured to the nut member and vertically movable with the nut member, and a plate member forming a guide member for guiding the vertical movement of the movable member, the drive shaft and the guide member being disposed substantially parallel to one another and being spaced apart from one another in a plane extending in a lateral direction of the seat back.