| 摘要 |
1,125,615. Preventing unauthorised use. Sept. 20, 1966 [Sept. 24, 1965], No. 40819/65. Heading F1B. [Also in Divisions G4 and H2] An anti-theft device particularly for a vehicle comprises a key-operated lock including an ignition switch 28, Fig. 3 for completing an electrical circuit such as a bridge circuit energized at 26, 27 from a battery 25 through ignition switch 28 and having an output diagonal 29, 30 coupled to a relay R which is energised to sound a horn 33 and short circuit ignition points 31 when ignition switch 28 is closed unless a key, Fig. 1 (b) or key ring assembly, Fig. 9 (not shown) provided with a predetermined bridge balancing resistor 10 is inserted in the lock to contact terminals 16, 24 connected to relatively insulated parts in the lock. The sensitivity of the bridge is increased by a transistor amplifier Tγ1, Tγ2. An additional slugged relay P is provided to disconnect the bridge after a short time if the correct key is used. The contents of a car may be protected by a key switch (38) Fig. 7 (not shown) on the outside of the car. A number of microswitches (M1 to M4) is parallel with each other and in series with the horn are fixed to the door, window, bonnet and boot of the car. The protection circuit may include a magnetic latching relay (R') Fig. 6 (not shown). |
