'BRAIN' TO PREVENT WRONG GEAR SELECTION
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INADVERTENT selection of a lower gear ratio while travelling at high speed in top gear can cause damage by "overspeeding" a vehicle engine. With heavy duty commercial vehicles equipped with multi-speed synchromesh gearboxes, a safeguard is of prime importance.
The motor accessory division of Smiths Industries Ltd. has designed and developed a speedsensitive electronic device which actuates a solenoid integral with the gearbox physically to prevent the vehicle driver selecting the wrong gear above a specified road speed. The first original equipment application is on the new Ford D1000 range.
The system consists of three basic component parts: a pulse generator (similar to the Smiths electronic speedometer pulse generator) and a frequency sensing, transistorized electronic "brain" containing a heavy duty output relay or relays depending on the type of gearbox fitted to the vehicle.
In operation the "brain"—a solid state device —receives from the pulse generator (driven from the gearbox final drive shaft) electrical signals which are proportional to vehicle road speed. At a predetermined frequency, the relay is operated causing the solenoid to "block" the appropriate section in the gearbox gate.
A self-monitoring facility is built into the control systems' circuitry providing a "fail-safe" characteristic in the event of component Failure or vehicle wiring damage.
LORRY-MOUNTED CRANES
WHITLOCK Bros. Ltd., Great Yeldham, Essex, says that the range of six Hojbjerg lorrymounted cranes formerly handled by Skandia Engineering Ltd., of rvlartlesham Aerodrome, Suffolk (CM, April 7), is now marketed as the Whitlock-I-IMF Autocranes. Following the liquidation of Skandia Engineering Ltd. a new company. Scanlift Ltd., has been formed to handle other Skandia agencies, including the Sunfab 410 crane and a range of automatic scissors grabs for use with lorry-mounted cranes.