Patent GB-1446747-A (GB)
Title: Vehicle equipped with safety harness and engine start prohibition system
IPC: B60R22/48
Filed: 1973-11-30
Abstract: 1446747 Engine inhibition safety systems NISSAN MOTOR CO Ltd 30 Nov 1973 [4 Dec 1972 2 March 1973] 55708/73 Heading B7H A system for preventing engine start whilst a seat belt is not correctly set includes a start circuit relay 10, a start gate circuit 12 and first and second energizing circuits, the first energizing the gate circuit 12 to pass a start signal to the relay 10 when an occupant sits and fastens the seat belt, and the second being responsive to engine start to maintain the gate circuit 12 energized until the ignition switch SW1 is switched off and the occupant vacates the seat. Both front seats have normally open switches SW3, SW2 respectively and seat belts with normally closed switches SW5, SW4, corresponding seat and belt switches being connected to respective relays RY3, RY2; a relay RY4 is controlled by relay RY2. Start gate circuit 12 is connected to the seat/belt switches by transistor Q2 which is in turn connected to the start relay 10 by switch S15. When contact m of the ignition switch SW1 is moved to accessories/preparation position S1 and the driver sits without fastening his belt, switches SW3 and SW5 are closed and relay RY3 actuated to close switch S6. In this condition Q2 is non-conductive and the gate circuit is not energized. If the driver shifts to a gear other than neutral a switch SW8 closes and a warning light and buzzer BZ are actuated, relay RY5 supplying the warning devices being actuated by the ignition switch. If the ignition switch is moved to start position S2 the light and buzzer actuate through switch S4 of gate circuit 12. Should the belt be fastened before seating RY3 is not actuated and the transistor Q2 is non- conductive. If the seated driver fastens his belt correctly in sequence the potential at the base of Q2 falls to render it conductive and energize the coil C3 of the gate circuit 12. On closure of S3 the ignition switch may be moved to S2 to energize the motor M and start the vehicle. A similar sequence of events occurs for the passenger's seat/belt circuit. The second energizer circuit includes an integrator 13 and a gate circuit 17 and allows the start gate circuit to be re-energized after the engine is stopped but before an occupant vacates his seat. When the engine runs point switch SW9 produces pulses which cause the integrator 13 to produce a trigger signal which actuates a relay RY6 of the gate circuit 14. If the engine stalls RY6 will remain energized until the ignition is switched off and the occupant vacates his seat. The connection of RY6 to circuits 10, 12 through connection D ensures that circuit 10 also remains energized. A third energizing circuit 19 allows the engine to be restarted when the ignition has been turned off for only a short period. This circuit includes a capacitor C3 which charges from the integrator 13 as the engine operates. Discharge of the capacitor through a discharge circuit 20 allows re-start until fully discharged. A fourth energizing circuit 22 allows energization of the start gate circuit 12 when no person is seated in the vehicle. This circuit includes an OR gate 23 connected at E, F to seat switches SW2, SW3 and to a transistor Q7. When no person is seated the OR gate 23 produces no signal and Q7 is conductive so that power is supplied from line 15 via Q7 and a diode D21 to the start gate circuit. Normally open switches SW6, SW7 are series connected to the warning buzzer circuit, SW6 being adapted to close when the steering is locked and SW7 being adapted to close when all the doors are shut.