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Experimental device may keep trucks from jack-knifing

Experimental device may keep t...
A new device could help keep transport trucks from jack-knifing (Photo: Shutterstock)
A new device could help keep transport trucks from jack-knifing (Photo: Shutterstock)
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A new device could help keep transport trucks from jack-knifing (Photo: Shutterstock)
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A new device could help keep transport trucks from jack-knifing (Photo: Shutterstock)

If there’s one thing that truck drivers don’t want their articulated tractor/trailer rigs to do, it’s jack-knifing. This typically occurs when the tractor skids on the road, and the momentum of the trailer causes it to swing out from behind, ultimately resulting in the tractor and trailer being folded up against one another – not unlike a jack knife’s body and blade. The folded rig usually ends up blocking the road, and the tractor can’t undo the situation under its own power. Fortunately, Greek researchers have recently created a system that they claim could greatly reduce jack-knifing.

First of all, there are already some technologies that help reduce the risk of a jack-knife occurring. These include anti-lock brakes in the tractor, electromagnetic brakes in the trailer, and devices that limit the angle between tractor and trailer at higher speeds. According to University of Patras engineers Nick Koussoulas and Stamatis Manesis, however, nothing tried so far has been sufficiently reliable.

What they have devised is a new type of kingpin. The kingpin is the junction where the tractor and trailer are joined, and it is normally situated in one static location on the rear of the tractor. The new kingpin, however, slides linearly, parallel to the tractor’s rear axle. In this way, sudden movements of the trailer result in the kingpin temporarily sliding over a bit, instead of having the trailer swinging out across the road.

Of course, a sliding kingpin could make regular driving of the rig rather challenging. That’s why the servo-driven sliding function would only activate in emergency situations, such as during hard braking – otherwise, the kingpin would remain fixed in one spot on the tractor.

So far, models of the system have reportedly indicated that it should “constrain jack-knifing to very low limits for a wide range of vehicle loading and road conditions.” The researchers are currently in the process of patenting the technology.

Source: Inderscience

16 comments
Slowburn
The problem is that the trailer has started sliding. I think the solution is either aerodynamic control surfaces or deployable ice blades.
MD
A Servo operated kingpin would work.... SB, remember that counter-steering in a car doesn't achieve anything until after the rear end has started to break loose.... Likewise the servo actuator on the kingpin acts to "counter-steer" the trailer and avoid the slide progressing towards accelerated instabillity... The best safety device for trucks is ABS / ESP... meaning you didn't lock up the brakes (on ice or gravel..) and run into whatever you were avoiding at "full speed", and then wrap the truck around everything else on the road..... If this works to keep it all in a straight line then it is an advantage.... Many different alternatives could be done to achieve the same result.... Have they actually put a full ESP system on any trailers?? because as it works to stop a car from rotating, it would also stop the trailer....
Florin Nicoara
How about a simple turn limiter in the turret for for any speed over 20mph? All you need is a couple of strong springs on either side and a electromagnetic tooth a few inches away that hits the spring at the 15 or 20 degree mark limiting it to a 30 degree max turn, on either side. It should be permanently deployed at speeds over 20mph under its own weight, but it is then electromagnetically raised up out of the way so the turret can turn all the way at low speeds for tight maneuverability. I'm surprised it has not been built already it is so simple and cheap.
Forest Fab
Springs to stop the rotation of the trailer would have to be quite huge to stop from rotating such a great mass with a great lever... The problem of jack-knifing comes from the fact that the trailer is pushing on the tractor behind its center of mass. An "easy" fix would be to relocate both the kingpin and center of mass of the tractor so that the trailer actually lines up with the tractor under braking. This would not solve the wheels locking though, so ABS or ESP on the trailer is also a great idea.
Mel Tisdale
Whatever happened to the system whereby the ability of the tractor and trailor to turn relative to eachother was constrained by the action of a kingpin brake that came into play when the road wheels were braking hard? With modern sensors that kingpin brake could be released if the unit was trying to form an angle between the tractor and trailor that would result from the driver's steering action, thus taking full advantage of the anti-lock braking system to enable the driver to steer round any obstacles.
Vic K.
For the record, the kingpin on a tractor-trailer is a large metal bolt affixed to the underside of the trailer. It couples to a latching mechanism on the tractor known as the 5th wheel. I'm curious whether the system described in the article is actually a moving kingpin or moving 5th wheel.
pmshah
Experimental 4 wheel Bose suspension reacts extremely fast to give extraordinarily improved ride comfort on roughest road. If that fast reacting program and hardware can be adopted to work for this purpose it should work out great.
windykites
I seem to recall anti-jack-knifing devices being around in the 60s.
robinyatesuk2003
sounds like a great idea which will sell in huge numbers unlike the deployable ice blades someone suggested
MD
FF.. forgetting one important thing.... Axle loads.... Trucks are designed to carry stuff... the distribution is set-up so that the correct weight distribution is on all of the axles under normal operation.. Sure the triler pushes on the Prime mover behine the Prime mover's centre of mass, but with a load on the turntable, that load becomes part of the 16 tonne mass on the rear tandem drives.. (or single drives in countries without tandems) THe truck doesn't actually know where the mass comes from, the fact that the axles see the weight is all that matters... This solution takes a control approach,.. ANOBM.. springs could be dangerous too... setting up potential oscillations that make the situation on the prime mover worse. Also a sliding trailer, hitting any sort of "hard stop" will, either shear the "stop" off, or start the tractor (prime mover) spinning due to loss of traction earlier than it would otherwise. Kinetic energy and momentum are powerful factors. (Was going to say force, gotta be more precise)