Procon-ten
Procon-ten (of per Grammed con traction and ten sion ) was a brand for a system to increase the passive safety in motor vehicles , which the event of a frontal impact, the steering column retracts and the seat belts tightens. The system was developed by Audi in the 1980s and registered as a trademark, which was deleted in 2002. It was installed in the Audi 80 B3, among others .
The mechanically operated Procon-ten consists of steel cables that connect the steering column and the front seat belts to the engine block via pulleys in the area of the front wheel suspension . In the initial phase of a frontal impact, the engine block is pushed between the front wheels in the direction of the passenger compartment . By redirecting the ropes, this movement is used to pull the steering column and pedals away from the driver in the opposite direction and at the same time to tension the seat belts.
The main purpose of the system is to reduce the risk of head injuries from hitting the steering wheel. The belt tensioners also reduce the risk of injury. At the time when Procon-ten came onto the market, airbags were not part of the standard equipment, but were not even available in many models and available at an additional cost in others. Airbags were considerably more expensive than the Procon-ten with 1000 DM. A technical limitation of Procon-ten is that it only works in the event of a frontal collision that pushes the engine-gearbox combination into the cardan tunnel.
With the fall in the price of airbags and after the initial reservations that an airbag could ignite in an uncontrolled manner, Procon-ten was taken off the market.
disadvantage
The steel cable around the engine block and transmission pulls the steering wheel into the dashboard at the same speed as the impact itself lasts. This process usually only takes a few milliseconds. The engine block adopts the new position in terms of speed, as does the steering wheel. All the forces that act on the engine block are thus transferred to the steering wheel in the negative direction via the steel cable. This means that several kilonewtons can pull on the steering wheel within a few milliseconds, which can have fatal consequences:
If you are taller, your knees can be injured in a collision if the steering wheel is jerked into the dashboard. In particularly severe cases of impact (at more than the 30 to 45 km / h commonly tested at the time), the driver's footwell is greatly reduced by 40% with a front cover. When using the Procon-ten, people who are taller than 1.80 m may well be seriously injured due to the steering wheel snap back and the additional reduction in foot space; in the worst case, there is the possibility of debris breaking the knees and lower legs of the driver. Since the steel cables leading to the belts exert enormous pressure forces on the passenger cell, it can also be deformed somewhat, so that the doors cannot be opened after an accident. In addition, after the system has been triggered, the vehicle is usually irreparably damaged, even in minor accidents, because the B-pillars are bent by the forces acting on the upper deflection points of the belts .
