Ford, which last year donated its self-applying seat belt to the Government, today reveals details of a new belt system.
Man gets into car
Man turns ignition, Seat belt light lights up
c.u. Seat Belt light
m.c.s. Man puts on seat belt
c.u. seat belt clamp
c.u. seat belt light off
c.u. sensor on seat belt, pan to receiver on roof pillar
Man starts car
Ext car away
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Background: Ford, which last year donated its self-applying seat belt to the Government, today reveals details of a new belt system. Designed to be foolproof, it is based on existing seat belts in cars, but employs electronics to 'see' that the harness is worn correctly.
The originality of Ford's approach lies in the use of an ultrasonic system to prevent the car from being driven unless the driver and front passenger are wearing their belts properly.
Other types of electronically-controlled seat belts concentrate on buckle-switch ignition and seat-sensing devices.
THE MISSING LINK
"We have watched all these developments with growing interest," said Mr Allan Aitken, Director of Car Engineering at Ford. "But we felt there was a missing link. None of them really made sure that the driver or front passenger was properly belted-up. In fact, some people will go to almost any lengths to avoid wearing an ignition-linked belt system. They sit on them, or wrap them round the back of the seat. Some have even cut off the buckles.
"So we asked our engineers to look for a completely different approach; to find a foolproof system which would only work if the belt was worn properly."
When an advanced prototype had been made, Ford engineers subjected it to severe tests, looking for ways to cheat or tamper with the system.
It is designed so that the engine will not start until the driver first sits down, which depresses a sensor in the seat. Then all he has to do is correctly buckle the belt across his torso. The system moves immediately into action, sending an ultrasonic signal from a transmitter mounted on the belt. Unless the receiver on the 'A' pillar can hear the signal the circuit cannot be completed.
The system's 'logic' may be adjusted so that the car can be moved in first gear or reverse without the ignition being cut. This would allow the car to be garaged last thing at night, or manoeuvred in a car park without the driver having to wear the belt for a short period. And a delayed-action device may be necessary in case the buckle is accidentally released while the car is moving.
But these are regarded as matters of refinement only. Major potential drawbacks have already been overcome. Engineers have designed the system so that it remains unaffected by brief interference, such as a flapping tie, thick tobacco smoke, or casual hand-movements crossing the ultrasonic beam.
The electronics company of Mullard Ltd is co-operating in the development of the ultrasonic equipment for the car. Development of the belt system is under the control of Wingard Ltd.
Ford believes that the system offers a viable alternative to the passive type of restraint-whether in airbag form, or the self-applying belt, itself originally Ford-patented and donated last year to the Road Research Laboratory.
The latest seat-belt idea from Ford is an ultra-sonic development of the lap-diagonal belt currently fitted in cars. The new system depends on the harness being properly worn before the car can be driven. The engine will not start unless a sensor in the seat (C) is depressed by the weight of the driver, who must buckle the belt properly across his body (B). Only then is the ultrasonic signal emitted from a small transmitter mounted on the belt (A) to a receiver on the A-pillar to complete the electronic circuit.