Patent US 6,728,616

An apparatus for preventing occupant injury during accident has various features to ensure safety. A sensor (70), detecting seat belt engagement is provided. In addition, there is a means for varying the tension of a seatbelt (17), depending upon the weight of the occupant (110) and the speed of the vehicle carrying the occupant (110). When said occupant (110) seats on any of the seats (17), the load cell switch (18) will close, allowing the load cell output energy to energize the control module (25). The control module (25), after receiving signal communication from any of the said load cells (15), enables the counter (50) to count the number of closed load cell switches (18) before enabling the optoisolator switch (70), to then energize the latching relay (80) to check for the seat belt latching of the occupied seats (10) with closed load cell switches (18) to assure occupants safety. When the switch (18) for the occupied seat (10) is closed, the latching relay (80) circuit will also be energized so that the seat belt (17) for the occupied seat location is checked for buckling. The latching relay (80) circuit and the counter (50) circuit are closed only when an occupant (110) takes any of the seats (10). The latching relay switch (85) is only energized when the counter circuit (50) is closed.