pivoting frames and mounting campers

IdaSHO

IDACAMPER
As to that diagram being the prescribed mounting preference for any OEM, I'd like to see something to back that up besides conjecture on the internet.


What, does your google not work?


Here's a MOG for ya'

Front and rear lateral pivots, center longitudinal pivot.

mercedes-benz

fahrzeugkonzept_uhe_systemk_en.jpg


U4023-U5023-unimog-chassis-design-715x230.jpg.asset.muOEM5K-zZEDPNBrNGW3FdvCao1oErW2kCrFv07HTXg.jpg


http://www.rygormercedes-benz.co.uk...imog_overview/u4023-u5023/chassis-design.html

http://www.emercedesbenz.com/autos/...ds/attachment/mercedes-benz-unimog-13c429_64/
 
Last edited:

IdaSHO

IDACAMPER
Well at least you've made it clear that your only arguing to argue.


You asked for an OEM supported example, and I gave it to you.
Yet you still seem to think your understanding of the subject trumps that of their engineers.

Good luck with that.


There is always more than one way to bake a cake.
This is certainly one of them.

Both methods have been utilized for decades, across a multitude of chassis'. And both work.

But your assumption that a small deflection in a chassis voids any such argument for a 4-point pivot mount is flawed.
Simply utilizing bushings in the front and rear pivots provides for more than enough give if any such forces were applied.
Sure, if things were hard mounted a bind would be present, but there isn't, due to bushings being used.

This design also reduces the overall rigidity requirement of the camper box, as it rides on these pivots freely, instead of always interacting with the springs of a sprung subframe.
 

toylandcruiser

Expedition Leader
Interesting how "degreed engineers" always put themselves up on pedestals. I've corrected a many engineers. They always brush me off and bring up their degree. But in the end they see the lights and change whatever it was.
 

IdaSHO

IDACAMPER
Interesting how "degreed engineers" always put themselves up on pedestals. I've corrected a many engineers. They always brush me off and bring up their degree. But in the end they see the lights and change whatever it was.

funny how that works, right?

"Works" is too vague & subjective. How long will the box live and what is its desired life-span? If it out-lives it's desired life-span then "works" is fine. In this venue I really don't like building something twice, so I take desired life-span to be infinite.


I understand the mentality. but this is where even I will differ from most hard-headed engineers.

I'm pretty hard headed and build things considerably better than traditional standards require, but I'm also realistic. I know plenty of engineers, and have a few in the family.

All are hard headed, few are realistic. And to go from numbers and sketches on paper to working model that is actually worth a dam, you have to be realistic.



Life span is everything. But it must still be relative.

No different in the industry at hand.

And get over it, "infinite" even if plausible, has no business being near a vehicle, period.

Again, come back to earth and be realistic.

I am in no way dis-counting the raw physics. But I am discounting how relative they are to the topic at hand.



So maybe back your thoughts up with some accounts that support your claims.

As in, connect the dots from your engineering standpoint to applicable, realistic accounts.
 

IdaSHO

IDACAMPER
That is one funny scene.

While I like Chevy Chase, my sig is not in reference to that.


Its a reference to Dr Who ;)
 

pappawheely

Autonomous4X4
I'm not sure why you guys are getting into a heated battle over this. I know, I worked as a non-degreed engineer for years. Engineers can be a pain in the *****. Some are too strident on what the book says while others are brilliant problem solvers. I have cursed automotive engineers for years with their sometimes dopey designs. In my opinion, physics always gets the last word. What ntsqd is arguing is simple physics. I have nothing but respect for you IdaSHO; you have built a beautiful camper but I am not a fan of the point loading that takes place with the pivot design and the mog design just does not make sense to me. In the end, we all have to live with the ultimate truth that perfection only exists in nature. Anything man-made is prone to failure.
 

Pntyrmvr

Adventurer
I agree that following the chassis maker's requirements has to take precedence. I believe the issue here is also going to depend on the box design and how flexible it is with torsional loads as it "follows" the frame twisting. A perfectly solid box will restrict the frame possibly breaking connection points and a flexible box may destroy interior components that are securely attached within, and built square to, the box.

The question here really ought to be how flexible does the entire combination need to be to avoid damage at either end of the flexibility spectrum.


"Talk is cheap. Whiskey costs money."
 

grizzlyj

Tea pot tester
Hi
.
O/T but despite MAN Kat 1 having a really stiff frame, the normal (?) German army mounting system is still used with the typical shelters by the likes of Zepplin having a stiff frame within the container walls, the frame will twist a little, and the cross straps holding the two together are chain at the ends but with a springy section to allow some twist. Any box then can go on any truck.mankat shelter.jpg
 

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