Ballrace turntable

The yanks dont run ballrace turntables under the Quickreleace 5th wheels
n they wunder why we need m here in Oz



Your input it sort

Wot say U
Cya

[ch9786]

Swishy,
Most of that damage will buff right out....

I'm not really up with all the info on turntables, can you explain what exactly went wrong in these situations?

My truck has a ballrace turntable, so hopefully the above won't happen to me?!!??! (Other than driver error!)

-Stuart

Swishy - I don't think you could put the blame for all those wrecks on just not having a ballrace fitted .. but yes, ballraces are good, they reduce stress on the turntable area .. are good for heavy loading .. and they widen the "footprint" of the front of the trailer, to improve stability.
A lot of truck drivers don't understand, that when you turn sharply, with a standard single-pivot-point turntable, you're effectively reducing your trailer support points, from four points of support, to only three.
The two pivot pins have turned in an arc and have reduced the width of support at the front of the trailer. They have effectively reduced the support points from two to one.
If you have a high C-of-G on your trailer, (as in the big pipe loaded on the Schnabel trailer, that fell over) .. you're asking for trouble just using a standard turntable.

A ball race improves truck handling, and reduces loading and wear on the QR turntable itself .. and if ya wanna go the whole hog and get a Rolls Royce ballrace .. ya buy a BPW, double row ballrace ..

www.dangelo.com.au/fifth-wheel-assembly....roduct=BallracePlate

www.bpwtranspec.com.au/bpw/index.php?opt...gory&id=16&Itemid=32

We had a BP tanker here in Perth, that lost a full trailer a few years back, while wheeling around a corner, just after pulling out of the BP depot in Kewdale. It had a ballrace fitted .. but all the bolts holding the turntable to the chassis sheared off ..

It seems that a few of the bolts had come a little loose sometime .. and the looseness wasn't easily visible .. but it was enough to severely overstress the remaining tight bolts .. that then sheared off .. and once they went, the loose ones followed .. :'(

Fortunately, despite carrying a full load, and the trailer rolling over .. it didn't result in a disaster .. and there was only a relatively small fuel spill.
There WAS a major investigation into the accident, though. The conclusion was that more thorough turntable checks needed to be carried out on a regular basis.

Here is the turntable on my truck...

From my limited understanding, if the trailer is fitted with a 'block' I should take the pin out to allow the turntable to rotate. If the trailer isn't fitted with a 'block' I must fit the pin to lock the turntable in place.

Is this correct? What damage would I expect if got this wrong?

-Stuart

[img]www.smcswainengineering.com.au/tt.JPG[/img]

Correct Stuart,
If you put a ( no block trailer) onto an unlocked ball race turntable what will happen is that when you come to unhook it, you will have problems, as the slot in the turntable probably wont be facing the back.
If you put a block trailer onto a fixed turntable you wont be able to go round corners ( unless the block snaps off) More serious issue here.
I like ball race turntables, they seem to steer better but there is sometimes a problem coupling up, as the thing rotates if you are not exactly centred. When all else failed I used to temporarily lock the turntable, then unlock it before driving off.

I was all ways told,
When backing under a trailer with Block & Ball race all ways lock the race & back straight, once the table is locked to the trailer, unlock the ball race.

But I can remember one person forgot to unlock the race on a A trailer and did a lot of damage to both trailers.

This is an interesting topic this one.
Our old turntables used to have what we called a greasy plate.
We found we had alot less spring damage on the truck suspension using them offroad. More osilation available I suppose.
Looking at what you all said I see now they were basically a poor mans ballrace. We had the pin to lock it ahead when hooking up then release when the jaws are locked.
Back up without the lock engaged and the plate would spin around all cock eye.
We didnt have what you refer to as a "block" though so sometimes when you went to unhook you have to take the pressure of the plate and spin the turn table around with a crow bar to a position you could lock it then you could release the jaw.
What does the block look like and where is it ?

Basil

The block was on the trailer and slipped into the V on the turntable to allow the turntable to stay straight with the trailer.

I see if I can find some photos

That makes sense now.
That'd be why the turntable was always sitting anywhere but dead ahead. Trailer didnt have the block.

Basil

I would only lock the turntable for a trailer with block when all else failed, as it was often hard to get the pin out again, especially if there wasnt a lot of room to get your arm in. If you were dead centre and the trailer and prime mover were level they usually hooked up all right without locking it. Would be a lot harder with a B Double (pushing A under B ) but I think they always use fixed turntables there.
I was told once that rigid trailers ie fridge pans and tankers should be on a ball race turntable to prevent cracking the prime mover chassis but that doesnt seem to apply these days.