The invention generally relates to automotive safety restraint systems and more particularly to a pretensioning system capable of simultaneously removing the slack in a plurality of seat belts, secured about respective occupants, utilizing a single pretensioning or belt-tightening device.
Pretensioners or belt tighteners, as they are also known in the art, are used to tighten a portion of a seat belt system, thereby removing slack about the occupant, during an accident. This action is done prior to the time the occupant begins to move forward as a result of the deceleration of the vehicle.
As a typical accident progresses, the occupant will remain fixed to the seat and begin to move forward at about 20 milliseconds after the initiation of the crash. Belt tighteners must react and eliminate the slack in the seat belt system, about the occupant, prior to the occupant's moving forward. Typically the pretensioning system is designed to react quickly and eliminate the slack in about 10 milliseconds upon receipt of a control signal, which is generated by one or more crash sensors and associated electronic control systems. There exists in the art two basic types of seat belt pretensioning systems. The first is associated with the spool of a retractor and the shoulder belt of a three-point seat belt system. During the accident the spool is caused, by various means, to reverse-wind or retract thereby removing the slack, typically in the shoulder belt portion of the seat belt system, to thereby hold the occupant in place. The other type of pretensioning system is called a buckle pretensioner. The buckle pretensioner is typically connected by a length of seat belt webbing or by a cable to the seat belt buckle. These buckle pretensioning systems (as well as retractor systems) include a pyrotechnic element which is fired, causing the buckle to be pulled downwardly, thereby reducing slack about the occupant. The prior art generally shows one pyrotechnic element associated with each shoulder belt (for the retractor pretensioner) or with each buckle (for a buckle pretensioner).
It is an object of the present invention to provide a single pretensioning device that is capable of eliminating the slack in a plurality of seat belt systems.
Accordingly the invention comprises a system for eliminating residual seat belt slack about a plurality of occupants of a vehicle, the system comprising: a plurality of seat belt assemblies securable about each respective occupant, each seat belt assembly including a lap belt, a tongue, and a buckle. One end of the lap belt is secured to a support member and an opposite end of the lap belt is operatively joined to the tongue. The buckle matingly locks with the tongue and the buckle is secured to one end of a connecting member, the connecting member having an opposite second end. A belt tightening means, secured to the second ends of each connecting member, generally simultaneously tightens each seat belt assembly about a respective occupant. Each belt assembly may also include a shoulder belt.
Many other objects and purposes of the invention will be clear from the following detailed description of the drawings.