Belt retractor for a seat belt
View Patent ↗A belt retractor for a seatbelt comprising a retractor pawl which blocks the seatbelt from being pulled out of the belt retractor in the event of an accident, and having a tightening device which tightens the seatbelt in a hazardous situation, the tightening device includes a tightening pawl which, in a blocking position, blocks the belt retractor in the belt uncoiling direction and, in a release position, leaves the belt retractor unaffected. The tightening pawl is assigned a sensor which monitors the position of the tightening pawl and transmits a signal indicating the position of the tightening pawl to a control device of the tightening device.
1. A belt retractor for a seat belt comprising:
a belt reel;
a retractor pawl which blocks the uncoiling of the seatbelt from the belt reel in the event of an accident; and
a tightening device which tightens the seatbelt in a hazardous situation;
wherein the tightening device includes a tightening pawl which, in a blocking position, blocks the belt reel in a belt uncoiling direction and, in a release position, leaves the belt reel unaffected;
wherein the tightening pawl is assigned a sensor which monitors the position of the tightening pawl and transmits a signal specifying the position of the tightening pawl to a control device, and
wherein the control device is configured so that when a signal is received from the sensor indicating that the tightening pawl has moved into the release position, the control device stops rotation of the belt reel in a tightening direction.
2. The belt retractor according to claim 1 , wherein the belt retractor includes a toothed ratchet wheel which is connected in a rotationally fixed manner to the belt reel and interacts with the tightening pawl.
3. The belt retractor according to claim 2 , wherein the tightening pawl, in the blocking position, forms a form-fitting connection with a tooth of the toothed ratchet wheel.
4. The belt retractor according to claim 3 , wherein the form-fitting connection is formed by an undercut.
5. The belt retractor according to claim 2 , wherein the tightening pawl is connected to a restoring device which automatically separates the tightening pawl from the toothed ratchet wheel as soon as there is no longer a form-fitting connection between the tightening pawl and the toothed ratchet wheel.
6. The belt retractor according to claim 5 , wherein the restoring device is formed by a restoring spring.
7. The belt retractor according to claim 1 , wherein the tightening device is configured to rotate the belt reel in the belt coiling-up direction to release the blocking position of the tightening pawl.
8. The belt retractor according to claim 1 , wherein the tightening device rotates the belt reel exclusively in the belt coiling-up direction until the sensor produces a signal which indicates the release position of the tightening pawl.
9. The belt retractor according to claim 1 , wherein the tightening device is configured to continuously monitor the position of the tightening pawl with the sensor during the presence of a hazardous situation.
10. The belt retractor according to claim 9 , wherein the tightening device is configured to repeat the tightening process of the seatbelt if the sensor indicates that the tightening pawl is in the release position when a hazardous situation has not ended.
11. The belt retractor according to claim 1 , wherein the sensor is a Hall sensor and the tightening pawl is at least partially magnetic.
12. The belt retractor according to claim 1 , wherein the sensor is an optical sensor.
13. The belt retractor according to claim 12 , wherein the optical sensor forms a light barrier.
14. The belt retractor according to claim 1 , wherein the sensor is formed by an electrical switching contact.