lie controller
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AN ANTI-jacknife device, 01 ginally designed by a Scottis engineer, may be develope now by an American con pany.
The device, which its inver tor G. H. Nichol calls a jacknil • arrester, is fitted to th articulated vehicle's kingpi and fifth wheel coupling.
Two pneumatic cylinder are located under the couplim with 44mm (1.75in) diamete ram bolts. The cylinders an connected by airline to a valv( built into an electric solenoic which is mounted on the unit': chassis.
This in turn is wired to switch in the cab, and tell-tale system in the airlin lights a warning lamp to indi ate when the ram bolts have een energised and have posively entered the brake arres3r drum fitted to the trailer.
Air for the device is supplied rom a separate reservoir so here is no direct connection vith the vehicle's brake sysem.
On the trailer an inner and niter casing contain a drum vhich has two 44mm 1.75mm) holes to locate with he ram bolts.
The existing kingpin is built nto the inner casing and held. n place by eight set screws through the top cover of the unit.
On top of the drum is a Ferodo disc and it is this that provides the retardation on the fifth wheel coupling.
However, when the device is inoperative the friction disc is held free.
The sensing of the unit is from road speed and the device is designed so that when road speed drops to within zero, the pressure disc is fully pressurised. Slight retardation of the disc starts at around lOmph.
The device's inventor says that there is allowance for larger diameter kingpins to be fitted and a vehicle fitted with the equipment can be locked manually to enable it to pull away in a straight line if in difficulty.