Tightening belts (PRETENSIONER SEAT BELT)-also known as shrinking seat belts. This belt is characterized when the car the moment of collision, occupant has not yet moved forward it when first tensioning strap, immediate occupant tightly strapped to the seat, and then locking strap to prevent passengers leaning forward, effective protection for the crew's safety.
Tightening belts play a major role in the rolling device different from the ordinary seat belts, in addition to ordinary rolling retractable lanyard features, when drastic changes occurred when the vehicle, in about 0.1 second strengthen crew's binding, so it also has a control device and pre-tensioning device.
The basic principle
Ideal belt is: first of all, timely tightening in the first moments of the accident did not hesitate to put people "press" on the seat. Then, moderately relaxed, peak impact in the past, or who have received air bag protection, proper relax seat belts. Avoid pulling too large to rib injuries. Advanced seat belts with pre-tightening device and force limiters, let's take a look at the features of both principles.
And belt tightening device when the accident occurs, people forward, seat-back, if the belt is too loose. The consequences are likely to be: crew out from under the seat belts: or, person has touched the balloon, and seat belts at this time because too much and failed to tighten tensioning allowance, would have been wished to eat as part of force, but rather the entire burden over to the balloon. Both of these conditions are likely to lead to crew seriously injured. But the problem is on the correct installation of seat belts. Its loose from where? Is due to the crew's clothes itself has a certain thickness, and more or less hidden part is loose in the seat belt device, which cannot be eliminated, but real accidents, should also try to eliminate. What should I do? For this belt tightening device it is responsible for providing instant tightening of belts. Its role is: first by a probe to collect crash information, and then release the pulse, the pulse is passed on to the gas generator, detonating gas. Explosion of explosive gas in the pipeline, the so-called ball chain, sending the ball in tube on channeling, Ratchet led dial.
Catch plate with uranium as a single entity, a seat belt around on an axis. Briefly, is the gas pressure on the ball, the ball driven pawl dial, pawl drive axis-pre-tightening-moment to achieve a
seat belt features. From perception to complete the whole process of belt tightening only lasts thousands of a second. Pipe ends are cut cavity, used to host rolled over the ball.
Second, the seat belt tension limiter after the accident, under the effect of seat belts in pre-tightening device, have been strained. But we hope that after the peak force, belt tension immediately reduced to reduce occupant forces, this particular task is done by the seat belt tension limiter: seat belts on the device, there is a pre-tightening device as described earlier, winding under a seat belt. Shaft is a steel torsion rod. When the load reaches the intended situation, reversing the rod begins to distort, this relaxed to some extent in the seat belts, implement seatbelt tension limit functionality.
Control unit there are two:
-An electronic control device from the electronic control unit (ECU) detects abnormal changes in vehicle acceleration, after computer sends the signal to the rolling control device, fire pre-tensioning device, this tightening belts are often used in combination with secondary air bags.
And a mechanical control device, sensor detects abnormal changes in vehicle acceleration, pre device control device to stimulate work, such tightening belts can be used separately.
Tensioning devices come in many forms, a common pre-tensioning device is a knock, initiators, gas by gas generating agent, catheters, the piston, the ropes and drive wheels. Dang car was collision Shi pre-pulled tight device was fired Hou, sealed catheter within bottom of gas raised agent immediately spontaneous combustion, detonated same sealed catheter within of gas occurred agent, gas occurred agent immediately produced large gas expansion, forced piston up moved pull ropes, ropes led driven round rotating, driven round makes volume received Manager reel turn, weaving with is volume in reel Shang, makes weaving with is back pulled. Finally, emergency lock for rolling Ribbon, occupant body fixed to prevent leaning to avoid collision with the steering wheel, dashboard and Windows.