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The objective of this paper is to introduce a web-clamp concept which can be adapted to emergency locking retractors (ELR's) or entirely replace these current seat belt locking devices in order to enhance the safety of car passengers in collision-accidents. Different types of web-clamp systems which demonstrate the discussed clamping concept are demonstrated and evaluated in comparison with the current ELR, as well as the pyrotechnically pre-loaded ELR system. The theory of the clamping concept as developed here, as well as different designs with correlating performance data (safety, comfort), will be discussed. It will be shown that a well-adjusted restraint system based on this web-clamp concept can reach a safety and comfort level close to pyrotechnically pre-loaded ELR systems.

Production seats and specially designed research seats were analyzed with respect to seat-safety belt interaction under frontal crash conditions. The objective was to evaluate seat influences on effectiveness of safety belts, or any other restraint system. We determined that classical measurement techniques alone are insufficient to completely cover problems of seat-safety belt interaction. Supplementary evaluation parameters of dummy kinematics were therefore defined to clarify the poor safety design of current production seats necessary seat design development for increased safety. Proposals for possible effective seat design were then derived to satisfy necessary new safety requirements for seating.

From a biomechanical point of view, test criteria in current safety standards for passenger protection do not insure a sufficient over-all protection of quality. First, the deficiencies of data and criteria, responsible for biomechanical problems, are being analysed. Secondly, additional criteria are being defined, which we think are significant for a better over-all evaluation of restraint devices considering biomechanical facts. As a result of a dummy-crash-series, an analysis is presented, demonstrating correlations between the new defined and former criteria. The final aim is to develop a complete system of criteria. By the use of simple evaluation methods it would guarantee clear results concerning biomechanical properties of passenger protection systems. With this technique one can have correct biomechanical evaluations of restraint systems, gained from dynamic tests even with anthropometric dummies.

Our aim is to show that today's safety standards (FMVSS 208, EC-Proposals) are inadequate in the present state to ensure optimum protection for belted passengers. These standards do not take into account motion sequence during impact. The postulated tolerance limits - HIC, SI, forward displacements etc. - cannot describe the dynamic behaviour adequately. We emphasize the importance of motion sequence to ensure optimum biomechanic conditions, because motion sequence is the necessary prerequisite for any discussion about biomechanical tolerance limits. First results of our current belt-accident investigations indicate that this is an important problem. By applying experience from crash tests and accident investigations, we try to define simple and well-controllable criteria for motion sequence.

This force limiter produces a belt force so that at the maximum requested crash-velocity and each lower one the maximum possible relative forward displacement between passenger and vehicle will be nearly used. Thereby, the passenger loads by the belt will be reduced, as well as the decelerations effecting the passenger, at a lower than the maximum requested crash-velocities in accident statistics, injuries by the belt will be effectly reduced, mainly for people of fragile contitution. The princip of the force limiter is a hydraulic throttling member. Due to the relative speed between the passenger and the vehicle the force limiter produces a belt-force according to its F-vrel.-ratio. PROCEEDING - 1. the mathematical analogue-digital simulation of a simplified passenger-vehicle-model in order to get an optimized F-vrel.-ratio of the force limiter 2. construction of a test unit of a force limiter to approximate the theoretical foundings by hardware.