Hi all , i recently read a post on another FB page where someone's drawbar snapped , it was a heavy 4T van yes , but had 6" drawbar , they commented it was 2mm G steel section . I recently changed our hitch to a hitch ezy 3.5 tonne and had to cut the small square section that usually sits on the front and extends under at 45 degrees so I could get the tacks off the bolt heads that hold the hitch on. Anyway I could see inside the RHS and it was either 2mm of perhaps possibly 3mm but I'd err to 2mm . The 10mm thick hitch mounting plate is only welded on outside top edges . I'm going to get it welded on the underside edges also where we can reach . I find it disconcerting that the gauge of steel is that light ? Would that be std for most vans , our van has an ATM of 3360 the drawbar is 150 x 50 RHS.
Like everything Caravan and Motor Home built down to the minimum to save weight. I would expect the 2mm? would be considered fine by the engineers but like everything you need more than the minimum to be safer.
For me 3.5 mm would be the go. It's the bit that all the rest hang off.
What will they build the proposed 4.5 tonne Van's A frames and chassis rails that the Industry wants.
A friend recently repaired an 8x5 trailer by a well known maker. The A Frame had exactly six inches of welds holding the A Frame to the chassis of the trailer box.
Look at timber trusses on roofs. As a youngster we would walk on the trusses, these days I wouldn't dare they have been pared to the bone.
This prompted me to have a look at my 1999 21' 6" Jayco. A bit late after all this time I suppose ...
A frame from - 102 x 52 x 4mm box section (4" x 2") welded full length of all edges touching main chassis. Also has a 50x7 strengthening strap welded under A frame. (is that a 'flat bar truss' .. I think so)
Main chassis - 150 x 52 mm x 6mm box section (6"x2") . Cross members are pressed slotted & Galv C section welded to chassis rails.
Coupling plate - 8mm welded full length of all top edges touching A frame
Complete chassis & A frame steel hot dipped galv. (I think). Not a single sign of rust after almost 20 yrs.
-- Edited by Cupie on Sunday 12th of August 2018 02:07:46 PM
-- Edited by Cupie on Sunday 12th of August 2018 02:10:36 PM
-- Edited by Cupie on Sunday 12th of August 2018 02:13:25 PM
Read an article just now written by cabcar they state drawbars should be from a minimum of 4mm aust steel with a 50 x 10 mm flat bar truss underneath
Depends on the weight of the caravan. Not all are 3 ton. Many poptops are under 1500kg so 4mm + truss under is way over the top imo. 3mm ideal with truss for heavy vans around 3T.
Of course there is an Australian Standards minimum on drawbars but you'd need an engineer to work that all out. Hence I've simply copied similar weight of trailers with ATM of 1 ton for my future 850kg caravan. Mind you if one can take on a little more weight the flat bar and truss under is worth the effort.
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Be nice... if I wanted my school teacher here I would have invited him...
The other thing that needs looking at is the outriggers off the main frame that support the side walls of the caravan.
Some manufacturers have had trouble with side walls dropping slightly due to outrigger issues.
Furniture separating from the walls in the form of small gaps is a dead give away for this problem.
Interesting Desert Dweller. By outriggers I assume you mean what I (likely incorrectly) call joists that are welded onto runners.
From the runners to the end of the ourigger could be about 300-400mm. Depending on the size/thickness of these and the weight of the walls and roof of the van, I think welding a simple 5mm rod from the end of the outrigger to the bottom if the runner should stop that drop occuring. I'd imaging thumping off road or on some Queensland tar roads wouldn't help.
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Be nice... if I wanted my school teacher here I would have invited him...
The other thing that needs looking at is the outriggers off the main frame that support the side walls of the caravan.
Some manufacturers have had trouble with side walls dropping slightly due to outrigger issues.
Furniture separating from the walls in the form of small gaps is a dead give away for this problem.
Interesting Desert Dweller. By outriggers I assume you mean what I (likely incorrectly) call joists that are welded onto runners.
From the runners to the end of the ourigger could be about 300-400mm. Depending on the size/thickness of these and the weight of the walls and roof of the van, I think welding a simple 5mm rod from the end of the outrigger to the bottom if the runner should stop that drop occuring. I'd imaging thumping off road or on some Queensland tar roads wouldn't help.
The outriggers are short cantilever members off the main frame, they're at about a meter spacing all along the main frame to support the walls. They can be rectangular tubing or angle members. The roof is supported by the walls which in turn is supported by the outriggers, so they carry a lot of weight.
If you look at used caravans you'll be surprised how many of them have furniture/cabinets/kitchen tops that have come away from the walls with a slight gap. This is due to the walls dropping slightly over time.
-- Edited by Desert Dweller on Monday 13th of August 2018 09:51:20 AM
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Cheers Keith & Judy
Don't take life too seriously, it never ends well.
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