Mercedes PRE-SAFE electric pretensioner
Mercedes PRE-SAFE electric pretensioner. Mercedes PRE-SAFE electric pretensioner.
Two words about the basic elements of any seat belt. The straps are made of synthetic ribbons and fastened with special threads. The lock mechanism is protected from deformation and can be easily opened even after an impact, and bolts with a special thread will hold the fasteners in place at extreme overloads.
The front belts of many modern models are equipped with height adjustment of the upper mounting point. The correct location of this point is very important, because the strap pulled up can damage the neck, and sharply going down will break the collarbone during overload.
A sensor is usually built into the lock, “calculating” the unfastened passenger. In its body is a spring-loaded core with a magnet at the end. Insert the buckle into the lock, the magnet goes to the reed switch, the contacts in it close - the pulse goes to the pillow control unit and turns off the warning signal. At the same time, the system does not forget to interrogate the "scales" under the seat cushion about the presence of a passenger on it.
In the rear seats of the Ford Explorer, inflatable sections are integrated into the diagonal straps. In the event of an accident, they additionally amortize, reducing pressure on the internal organs. Because of the risk of burns, cold gas is used in belts under less pressure than in pillows
In the rear seats of the Ford Explorer, inflatable sections are integrated into the diagonal straps. In the event of an accident, they additionally amortize, reducing pressure on the internal organs. Because of the risk of burns, cold gas is used in belts under less pressure than in pillows. In the rear seats of the Ford Explorer, inflatable sections are integrated into the diagonal straps. In the event of an accident, they additionally amortize, reducing pressure on the internal organs. Because of the risk of burns, cold gas is used in belts under less pressure than in pillows.
An integral part of the modern three-point seat belt is an inertial coil. Her task is to tighten the straps, automatically choosing a slack. The self-locking belt mechanism will help to fix the rider in the chair during sudden braking or accident. At the end of the coil mounted movable lever. When quickly unwinding under the action of centrifugal force, it moves and latches the coil stopper - the belt is locked.
But in the event of a serious accident, one lock is not enough. Then automatic pretensioners enter the struggle for life. Their mechanism winds the tape back onto the reel, choosing 100–150 mm of length. As a result, the moment of impact catches the passenger securely locked in the seat.
On the coupe and the three-door hatchback, the average strut is far back. To make it easier to fasten, a loop or hook is provided on the back of the seat, in which the strap is fixed. And in expensive models, the belt, after closing the door, will be supplied with a power rod
On the coupe and the three-door hatchback, the average strut is far back. To make it easier to fasten, a loop or hook is provided on the back of the seat, in which the strap is fixed. And in expensive models, the belt, after closing the door, will be supplied with a power rod. On the coupe and the three-door hatchback, the average strut is far back. To make it easier to fasten, a loop or hook is provided on the back of the seat, in which the strap is fixed. And in expensive models, the belt, after closing the door, will be supplied with a power rod.
An alternative solution for the front seats is to act directly on the belt lock, moving it closer to the floor. Most devices fire instantly at the time of impact, receiving an alarm from the airbag control unit.
However, the abundance and speed of sensors in a modern car allows you to calculate the critical situation in advance, even before contact with an obstacle or another car. So, the Mercedes PRE-SAFE preventive system, sensing something was amiss (for example, by triggering the stabilization system), will tighten belts in advance, close the hatch, and raise the seatbacks. The driving force of a conventional pretensioner is a squib or gas generator. The gas flow from the microexplosion acts on the piston or set of balls that rotate the gear of the coil or move the lock fastener.
One of the pyrotechnic pretensioner design options. The charge pushes the piston with a rack, which drives a pair of gears through the gear. One of them blocks the overrunning clutch - the belt is wound on a reel
One of the pyrotechnic pretensioner design options. The charge pushes the piston with a rack, which drives a pair of gears through the gear. One of them blocks the overrunning clutch - the belt is wound on a reel. One of the pyrotechnic pretensioner design options. The charge pushes the piston with a rack, which drives a pair of gears through the gear. One of them blocks the overrunning clutch - the belt is wound on a reel.
