Thread: Coupling for powered trailers

Originally Posted by Blknight.aus

why not just bolt a series diff in under the trailer and then direct couple a DC motor to the flange wire it up so that when you need the push it can draw from a bank of high discharge batteries and when you dont its either regenning or more simply charging from the alternator?

Yes, I guess that matching gear ratios isn't all that critical for the rare occasion that drive assist from the trailer is needed.
As an example. When I toured Vietnam a few years ago we passed through a province of around 20km radius where almost every vehicle was a grey Fergy sized 2wd tractor hitched up to a powered trailer, that consisted of an old truck with the cab, front axle and engine removed. Just the gearbox, propshaft and rear axle remaining. The front of the chassis rails were bent inwards to form the drawbar and a driveshaft from the tractors PTO coupled to the input shaft of the old truck gearbox.
It would be unlikely that any of the old trucks gear ratios matched that of the tractor, but any assist from the trailer was obviously better than a dead weight in the swampy terrain in that province.
Bill.

actually with an electric drive it doesnt matter because theres no mechanical coupling as the combination picks up speed the torque from the electric motor falls off, but that wasnt the key reason I suggested a series axle.

series axles are setup for leaf spring suspension and with the 4.7:1 ratio would give better initial gear reduction for the electric drive system.

Thinking about this, I first saw the Owens system in a book (LR workhorse of the world, which I just ordered a "New" copy of from amazon).

In todays systems I can imagine you could hook it up with the TC/ABS systems to engage/disengage drive as it received feedback from the tow vehicles systems. Just don't know what you'd use to couple the drive system engagement.

Originally Posted by Blknight.aus

why not just bolt a series diff in under the trailer and then direct couple a DC motor to the flange wire it up so that when you need the push it can draw from a bank of high discharge batteries and when you dont its either regenning or more simply charging from the alternator?

There was a stretched 6 wheel Rangie for sale in Gympie a couple of years ago with that system. He said it worked well up the beach.

Something to make the 101 purists throw up.
If one was to convert the rear suspension to coils, move the rear crossmember forward to just behind the rear axle, shorten the drawbar of the powered trailer so that the wheels were much closer to the rear wheels of the 101, and restricted trailer articulation to just roll and pitch but not yaw,
would it approach this kind of mobility? http://www.unusuallocomotion.com/pag...es-medium.html Click on photos to enlarge.

bill.

Originally Posted by wagoo

Ben, I am reasonably certain that Samurais trailer wasn't powered. I remember the story on the TTC event back then, and no mention was made of the trailer being powered, nor is there mention of it in the Google text you posted. There were other photos of the rig in the magazine articles, and there wasn't any evidence of a diff or other type of drive components on the trailer axle.

Bill - you may be right. I have (unfortunately) thrown out the mag during a cleanup, and I can't find anything conclusive either way - however from the pic it doesn't look like the Samurai has an extra drive shaft for the trailer...

Thanks all for your responses... Its all on the drawing board in an effort to build an offroad boat trailer that will weight up over the tonne - and need to get through soft sand mud and slop. No real need to be engaged except for short nasty sections that are generally straight.

Dave,
Series track is too narrow and would need to be widened... also wouldnt a series diff be geared too high for an electric input? I was thinking even a rover 3.58 would mean an electric motor free spinning at 2000rpm would be too tall a gearing. 4.7 requires more torque not less than 3.58 does it not?

I agree that electric has its benefits. Weight is a negative but the lack of coupling linkages is a positive. Any batteries used to power the trailer can be cross utilized to power the boats electric motor once fishing???? I would reckon a 12V winch motor would likely be useable source of power.

Hmmm, more thinking to be done

S

Originally Posted by roverrescue

...4.7 requires more torque not less than 3.58 does it not?

No, lower (numerically higher) gear ratio requires less effort to turn it.

How about hydraulic Steve? For short-term use on straight sections you could maybe even tap the PAS pump. Only weight on the trailer will be a small hydraulic motor + hydro lines...

You could even use hydro wheel motors to have independant operation!

Hydro components would probably be much better at holding up to water/mud/salt etc...