Protective device for restraining a passenger uses a seat sensor to detect a load level on a seat and a tension switch to detect tension on a seat belt moving it into a switch-on state with tension in a certain range.

摘要

A seat sensor (11) detects a load level on a seat. A tension switch (13) detects tension on a seat belt and moves into a switch-on state if tension lies in a certain range. A section (35) to decide on airbag operation determines if tension is under a lower threshold, if the tension switch is switched on, if the seat belt is locked or if the tension switch is switched off and the total seat weight is no more than a preset weight.