Abstract: A special restrained size device, with a gear reduction unit including a pilot motor and a series of Kinematisms, basically made of a train of toothed wheels, connected according to a scheme suitable for a trigger box being charged both by the car battery and by another small standby battery sheltered inside the car passenger compartment. The trigger box is planned to transmit a small electronic timer the impulse for the automatic safety belts quick-release some seconds (6-8) after a violent car crash and consequent motor stop. The safety belts quick-release can be obtained manually. The special structure of the whole of this mechanical device was conceived in order to connect it, through easy fitment and without considerable cost, with all the current best market-licensed safety belts.