Patent GB-1242841-A (GB)
Title: Vehicles having door locking means rendered inoperative by abnormal retardations and accelerations
Inventor: FINCH PETER MOLYNEUX
IPC: B60R22/48
Filed: 1968-10-14
Abstract: 1,242,841. Controlling vehicles. PRESSED STEEL FISHER Ltd. 14 Oct., 1968 [12 July, 1967], No. 32092/67. Heading B7H. [Also in Divisions E1-E2 and F1] In a vehicle each passenger door is provided with a locking device so operated by a solenoid 14 that when the solenoid is energized the respective locking device is actuated to a locking condition, an inertia switch 19 operable by a predetermined abnormal acceleration or retardation being arranged to cause the circuit to the solenoid to be broken when it is operated thereby allowing each locking device to assume an unlocking condition, and the ignition switch 11 being adapted to break the circuit to the solenoids when the ignition is switched off. In the circuit shown the inertia switch 19 is disposed so that when its contacts make during the predetermined acceleration or retardation a relay coil 17 is energized. The relay has three sets of contacts 12, 18 and 23; the contacts 12 constitute a change-over switch and when the relay coil is de-energized the solenoids are connected via the change-over switch directly to the ignition switch and hence to the battery so that when the ignition switch contacts are completing the circuit the solenoids are energized and in consequence the doors of the vehicle are locked. When the relay coil 17 is energized the change-over switch formed by the set of contacts 12 connects the solenoids to the ignition switch via switch contacts 21 of a thermal delay device ; the thermal delay device has a filament 22 which when it has been cooled to a predetermined extent causes the contacts of switch 21 to break. The filament 22 is connected via the set of contacts 23 of the relay and is normally energized via the ignition switch; the energization of the relay coil causes the set of contacts 23 to disconnect the filament 22 to allow the filament to cool. The third set of contacts 18 of the relay are holding contacts which hold the relay coils 17 energized after initial energization of the coil by the inertia switch. The relay 17 is de-energized by breaking the circuit to the coil through the ignition switch 11. In the circuit shown the ignition coil 11 is connected in parallel with the solenoids 14 so that it is also controlled by the relay and the thermal delay device. To enable the solenoids 14 to be de-energized by the driver a switch 15 is provided which breaks the circuit. In parallel with the inertia switch 19 is another switch 20 ; this switch is mounted in the housing of an inertia lock reel wound seat harness and is closed when the harness is retracted thus energizing the relay coil 17 and hence disconnecting the ignition coil from the ignition switch so that the vehicle cannot be started. The switch 20 is opened when sufficient of the harness strap has been withdrawn from the reel to enable a small driver to be strapped in place. The inertia switch can comprise an encapsulated dry reed switch mounted on a spring wire inside a cylindrical magnet so that under the predetermined acceleration or retardation the reeds overcome the force exerted by the spring wire and move towards the magnet thereby allowing the magnetic field to close the reeds. Alternatively the inertia switch can comprise a silverplated brass ball suspended by a spring wire inside an earthed hermetically sealed brass housing, acceleration or retardation causing the ball to contact the housing to complete the circuit; the predetermined acceleration or retardation can for example be 5G.