Towards Greater Vehicle Security
Page 75
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ASECURITY system developed by
Patfield Electrical 'Services, 63a Lyndhurst Way, Peckham, London, S.E.15, is said to be the first which prevents all doors on a vehicle from being opened and at the same time sounds an alarm when a forced entry is attempted. Another part of the system prevents either a petrol or oil engine from being started until a special switch has been set.
Basis of the system is a master switch which is connected with from one to 10 electric alarm locks in a circuit using the vehicle's battery. The master switch is mounted at any convenient point and is operated by a special key inserted from outside the vehicle. Alarm locks are fitted to all doors required to be secure, and when the key is turned clockwise in the switch an electrical impulse is transmitted to all locks, which then close.
Thus all doors are locked from one position, in one operation, and it is then impossible to enter the vehicle until the locks are opened by the transmission of a reverse impulse from the master switch. This is done by turning the key anticlockwise in the switch. In addition. attempts to force the doors open when the switch is set, start off an alarm which is only stopped by turning the key.
Once the locks are set in the closed position, no current is used and even if the battery is disconnected the locks will remain secure, The locks are strongly made and able to withstand a force of at least 1 ton—under test, a load of 3 tons has been applied to one lock before failure occurred.
To give protection against duplication of the keys for the master switch (only two are supplied with each switch), Yale blanks with special groove sizes are used. The particular design of blank is obtainable only from ratfields, and it is therefore only from them that spare keys can be obtained. In the event of a key being
lost or stolen, the master switch can be exchanged at a nominal charge for one having a different plunger arrangement and an extra safeguard is that skeleton keys cannot be used in the switch, because there is a comparatively high resistance to the rotation of the plunger barrel.
It is possible to fit the special locks to both hinged and sliding doors, to shutters, and also to braking systems, gearboxes and fuel-injection pump racks, to make a vehicle completely immobile.
In addition to the door locking system, a separate circuit is linked to the alarm. This incorporates a hidden switch which is used to break the ignition circuit in the case of a petrol engine or the battery isolating switch circuit in the case of an oil engine and make either inoperative. If attempts are made to start the engine. ihe alarm sounds and continues as long as the ignition or battery circuit is closed.