Arrangement for the automatic engagement of a hazard warning system

Claim 1

An arrangement for automatically engaging a hazard warning system of a motor vehicle which is operable to be selectively turned on and off by hand, in case of impact accidents and emergency braking situations, comprising inertia switch means which responds at least to impact-like accelerations acting in the road plane of the motor vehicle, a manually actuatable hazard-warning switch means including a turn-on switch for manually turning on the hazard-warning system, circuit means including a self-holding circuit operatively connecting the inertia switch means with the hazard-warning system for turning on the latter while bridging the manually actuatable hazard warning switch means, the hazard-warning switch means including further a change-over switch which, when manually actuated, turns off the hazard-warning system after its automatic engagement effected by the inertia switch means, by interruption of the self-holding circuit, an acceleration-sensitive circuit means which has a relatively lower response threshold and a delaying switching behavior, said acceleration-sensitive circuit means being operatively connected in parallel with the inertia switch means with relatively higher response threshold, the output of said inertia switch means and of said acceleration-sensitive circuit means being connected by way of an OR element with the circuit means including the self-holding circuit for the activation thereof, the manually actuatable hazard-warning turn-on switch being mechanically coupled with the change-over switch which is operatively connected in a loop including the self-holding circuit, and the change-over switch being operable to be switched without overlap between a voltage supply connected by way of an ignition switch and a voltage supply coming directly from a battery and thereby interrupting the closed self-holding circuit during such change-over switching.