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In an emergency situation of a vehicle, when an acceleration sensor moves an action lever up to a middle point, a forcing means rotates the action lever in its working direction and a pawl is separated from an action wheel by the rotating force of the action lever. Accordingly, a webbing takeup shaf

In an emergency situation of a vehicle, when an acceleration sensor moves an action lever up to a middle point, a forcing means rotates the action lever in its working direction and a pawl is separated from an action wheel by the rotating force of the action lever. Accordingly, a webbing takeup shaft is driven by the action wheel and an occupant restraining webbing is wound on to the webbing takeup shaft, whereby the occupant restraining webbing is caused to secure an occupant tightly, that is, an occupant restraining performance is enhanced.

대표청구항 ▼

1. A webbing tension device, capable of rotating an action wheel to wind an occupant restraining webbing on a webbing takeup shaft and capable of causing the occupant restraining webbing to secure an occupant tightly to enhance an occupant restraining performance in an emergency situation of a vehic

1. A webbing tension device, capable of rotating an action wheel to wind an occupant restraining webbing on a webbing takeup shaft and capable of causing the occupant restraining webbing to secure an occupant tightly to enhance an occupant restraining performance in an emergency situation of a vehicle, which comprises: (a) a pawl engaged with the action wheel to prevent the action wheel from rotating in a webbing winding direction; (b) an action lever opposed to the pawl and separating the pawl from the action wheel when the action lever is rotated in a predetermined working direction thereof, said action lever having a normal at rest position, said rest position defining a line of action; (c) a forcing means engaged with the action lever when the action lever is in normal position and tending to rotate it to one side of said line of action and in a direction opposite to its working direction; and (d) an acceleration sensor opposed to the action lever operable during a vehicle emergency situation to move the action lever from its normal position thereof to the other side of said line of action, the forcing means being operable when said action lever is at said other side of said line of action to rotate the action lever rapidly in the working direction and to thereby cause disengagement of the pawl from the action wheel. 2. A webbing tension device as set forth in claim 1, wherein an intermediate portion of the pawl is rotatably supported to a frame rotatably supporting the webbing takeup shaft, one side of the pawl is engaged with the action wheel and the other side thereof is opposed to the action lever. 3. A webbing tension device as set forth in claim 1, wherein one end portion of the action lever is rotatably supported to a frame rotatably supporting them webbing takeup shaft and a tip end portion thereof is positioned between the pawl and the acceleration sensor. 4. A webbing tension device as set forth in claim 1, wherein one end portion of the first supplementary action lever is rotatably supported to the action lever, the other end portion of the first supplementary action lever is rotatably supported to one end portion of a second supplementary action lever and the other end portion of the second supplementary action lever is rotatably supported to the frame for supporting the webbing takeup shaft, the said one end of the first supplementary action lever being rotated in tandem with the action lever by a spring force. 5. A webbing tension device as set forth in claim 1, wherein the end of the action lever opposed to the pawl is engaged with an elongated slot to guide the movement of said action lever as it moves from one to the other sie of said line of action and vice-versa. 6. A webbing tension device as set forth in claim 1, wherein the action lever comprises a pair of arms, one end of each of the respective arms being rotatably supported to the frame for supporting the webbing takeup shaft, the other end of one of the arms is formed with an elongated hole and the other end of the other arm is provided with a pin received in the hole. 7. A webbing tension device as set forth in claim 6, wherein the pair of arms are provided between one end portions thereof with a tension coil spring and the other end portions thereof are subject to a rotating force in a direction opposite to the working directions of the respective arms. 8. A webbing tension device as set forth in claim 1, wherein the action lever is rotatably supported to the frame for supporting the webbing takeup shaft, the action lever is forced in a direction opposite to the working direction by a tension coil spring arranged between the action lever and the frame, and, when the axial center line of the tension coil spring is moved through the rotatably supported point of the action lever by a slight rotation of the action lever, the action lever is rotated in its working direction. 9. A webbing tension device for winding an occupant restraining webbing to cause the occupant restraining webbing to secure an occupant tightly in an emergency situation of a vehicle, which comprises: (a) a frame mounted on a vehicle body; (b) a webbing takeup shaft rotatably supported to the frame; (c) an action wheel rotating the webbing takeup shaft to wind the occupant restraining webbing in an emergency situation of the vehicle; p1 (d) a pawl engaged with the action wheel to prevent the action wheel from rotation in an ordinary situation of the vehicle; (e) an action lever driving the pawl for separating same from the action wheel when said action layer is rotated in a predetermined working direction, said action lever having a normal rest position, said rest position defining a line of action; (f) a forcing means engaged with the action lever, said forcing means tending to rotate said action lever to one side of said line of action in a direction opposite to its working direction in the ordinary situation, and (g) an acceleration sensor operable in an emergency situation to rotate the action lever to the other side of the said line of action, said forcing means being operable when said action lever is at said other side of said line of action to rapidly rotate said action lever in its working direction and to thereby separate the pawl from the action wheel so that same can be rotated to wind the restraining webbing. 10. A webbing tension device as set forth in claim 9, wherein an intermediate portion of the pawl is rotatably supported to the frame rotatably supporting the webbing takeup shaft, one side of the pawl is engaged with the action wheel and the other side thereof is opposed to the action lever. 11. A webbing tension device as set forth in claim 9, wherein one end portion of the action lever is rotatably supported to the frame rotatably supporting the webbing takeup shaft and a tip end portion thereof is positioned between the pawl and the acceleration sensor. 12. A webbing tension device as set forth in claim 9, wherein one end portion of a first supplementary action lever is rotatably supported to the action lever, the other end portion of the first supplementary action lever is rotatably supported to one end portion of a second supplementary action lever and the other end portion of the second supplementary action lever is rotatably supported to the frame for supporting the webbing takeup shaft, the other end of the first supplementary action lever being rotated in tandem with the action lever by a spring force. 13. A webbing tension device as set forth in claim 9, wherein a part of the action lever is guided along an elongated slot to guide the action lever movement as it moves from one to the other side of said line of action and vice-versa. 14. A webbing tension device as set forth in claim 9, wherein the action lever comprises a pair of arms, one end of each of the respective arms being rotatably supported to the frame for supporting the webbing takeup shaft, the other end of one of the arms is formed with an elongated hole and the other end of the other arm is provided with a pin received in the hole. 15. A webbing tension device as sent forth in claim 14, wherein the pair of arms are provided between one end portions thereof with a tension coil spring and the other end portions thereof are subjected to a rotating force opposite to the working directions of the respective arms. 16. A webbing tension device as set forth in claim 9, wherein the action lever is rotatably supported to the frame for supporting the webbing takeup shaft, the action lever arms are forced in a direction opposite to the working direction by a tension coil spring arranged between the action lever arms and the frame, and, when the axial center line of the tension coil spring is moved through the rotatably support point of the action lever arms by a slight rotation of the action lever arms, the action lever arms are rotated in a working direction. 17. A webbing tension device, wherein a pawl is separated from an action wheel, the action wheel is rotated by a spring force and a webbing takeup shaft is rotated in a webbing winding direction thereof by the rotating force of the action wheel in an emergency situation of a vehicle, which comprises: an action lever, one end portion thereof being rotatably supported to said frame for supporting the webbing takeup shaft and the other end portion thereof abutting against the pawl in a normal rest position, said rest position defining a line of action, said action lever separating from said pawl when it is rotated in a predetermined working direction; a forcing means engaged with the action lever, said forcing means tending to rotate said action lever to one side of said line of action in opposition to its working direction; and an acceleration sensor abutting against the other side of the tip end portion of the action lever and at one side of said line of action, said action lever being operable in an emergency situation to rotate the action lever to the other side of said line of action, said forcing means being operable when said action lever is at said other side of said line of action to rapidly rotate the action lever in its working direction and thereby separate the pawl from the action wheel.