Safety devices for vehicle seats

Abstract

To provide a safety device for a vehicle seat which can reduce compression pressure to a spine of an occupant at the occurrence of a collision of a vehicle.SOLUTION: A safety device for a vehicle seat includes a reclining mechanism capable of adjusting the angle of a seatback, and protects an occupant sitting on a seat. The safety device is provided with a torsion bar unit including a first torsion bar whose one end is connected to the seatback on one side in the width direction of the seatback, a second torsion bar which is coaxially connected to the other end of the first torsion bar, and a lock mechanism for locking torsional operation of the second torsion bar. Torque characteristics T1 (N m) to a displacement angle of the first torsion bar is set to be larger than torque characteristics T2 (N m) to a displacement angle of the second torsion bar.SELECTED DRAWING: Figure 3

Claims

1. A vehicle seat safety device that includes a reclining mechanism that allows adjustment of the seatback angle, and protects occupants seated in the vehicle seat, On one side of the seat back in the width direction, a torsion bar unit is provided, which includes a first torsion bar with one end connected to the seat back; a second torsion bar coaxially connected to the other end of the first torsion bar; and a locking mechanism for locking the twisting motion of the second torsion bar. A safety device for a vehicle seat, characterized in that the torque characteristic T1 (N·m) of the first torsion bar with respect to the displacement angle is set to be greater than the torque characteristic T2 (N·m) of the second torsion bar with respect to the displacement angle.

2. The safety device for a vehicle seat according to claim 1, characterized in that the locking mechanism locks the twisting motion of the second torsion bar when the reclining angle of the seat back reaches a predetermined angle θs.

3. The safety device for a vehicle seat according to claim 2, characterized in that the locking mechanism comprises: a stopper arm provided at the connection point between the first torsion bar and the second torsion bar, which rotates in conjunction with the twisting motion of the second torsion bar; and a stopper member which, when the reclining angle of the seat back reaches a predetermined angle θs, comes into contact with the stopper arm to prevent further rotation of the stopper arm.

4. The safety device for a vehicle seat according to claim 3, characterized in that the stopper arm has sufficient rigidity to interrupt the interlocking of the first torsion bar and the second torsion bar when it comes into contact with the stopper member.

5. The vehicle seat safety device according to claim 1, 2, or 3, characterized in that the vehicle seat is equipped with a seat belt retractor.

6. The vehicle seat safety device according to claim 5, characterized in that the seat belt retractor is positioned near the upper end of one side of the seat back.

7. A safety device for a vehicle seat according to any one of claims 2 to 4, characterized in that, when the reclining angle of the seat back is defined as positive for the forward side and negative for the rear side compared to the vertical, the angle θs is set to +5° to -30°.

8. The vehicle seat safety device according to any one of claims 1 to 4, characterized in that the torsion bar unit is provided at both the left and right ends of the seat back.

9. The safety device for a vehicle seat according to any one of claims 1 to 4, characterized in that the reclining mechanism comprises a worm gear mechanism consisting of a worm wheel connected to the end of the second torsion bar opposite to the first torsion bar, and a worm that meshes with the worm wheel.

10. The reclining mechanism comprises a gear member connected to the end of the second torsion bar opposite to the first torsion bar, a locking member that restricts the rotation of the gear member, and a lever that releases the engagement between the gear member and the locking member, thereby changing the angle of the seat back, as described in any one of claims 1 to 4.

Images