Frame flex fundamental question
- Thread starter GR8ADV
- Start date
^^
http://www.expeditionportal.com/for...es-and-mounting-campers?p=1762802#post1762802
19 pages for your reading pleasure, sir.
There are a few more around and I have a few pics saved, I can email them if you want. One has a UHMW "board" instead of an oak timber between the body and frame, spring mount similar to above.
http://www.expeditionportal.com/for...es-and-mounting-campers?p=1762802#post1762802
19 pages for your reading pleasure, sir.
There are a few more around and I have a few pics saved, I can email them if you want. One has a UHMW "board" instead of an oak timber between the body and frame, spring mount similar to above.
http://www.robgray.com/graynomad/wothahellizat/index.php
Check out robs build on both his rigs. I like his design his reasoning behind it.
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Check out robs build on both his rigs. I like his design his reasoning behind it.
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GR8ADV
Explorer
I don't understand how with this design. I am not questioning, I just have questions. Please explain how this minimal gap does that. Thanks.
On the three point system you have two mounting points on on end of the box. During the frame flex these points move with frame. The other end has a single point centered between the rails. Which does not move with the frame, this way there less stress placed on your camper box.
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http://www.robgray.com/graynomad/wothahellizat/wot1/diaries/diary_09/index.php
Discussing twist
http://www.robgray.com/graynomad/wothahellizat/wot1/diaries/diary_10/index.php
Visual aids that may help.
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Discussing twist
http://www.robgray.com/graynomad/wothahellizat/wot1/diaries/diary_10/index.php
Visual aids that may help.
Sent from my QMV7A using Tapatalk
GR8ADV
Explorer
W
Ok I am almost getting smarter. The concept is very sound. I am having trouble of how it functions in the real world. In the pic below which is pretty typical and is the same in the side of the ATW
These are not shown on the sketch in the link I don't believe.
My headache is that these appear to limit the great frame movement in the sketch link to less than one inch to the frame. Thus when the frame drops to the left as shown the left spring (not shown) extends and the right side spring (not shown)!contracts. But it can only contract until the apparent very small gap is covered and it hits the frame in the right side ( way less than one inch or less) then it is business as usual with no spring benefit. I can't see a meaningful benefit. Now in the sketch link it shows a tremendous amount of frame flex before contact. Now this makes sense but does not jibe with what I 'think' I am seeing. But I really think I am missing something.
Sorry to be such high maintenance....
Ok I am almost getting smarter. The concept is very sound. I am having trouble of how it functions in the real world. In the pic below which is pretty typical and is the same in the side of the ATW
These are not shown on the sketch in the link I don't believe.
My headache is that these appear to limit the great frame movement in the sketch link to less than one inch to the frame. Thus when the frame drops to the left as shown the left spring (not shown) extends and the right side spring (not shown)!contracts. But it can only contract until the apparent very small gap is covered and it hits the frame in the right side ( way less than one inch or less) then it is business as usual with no spring benefit. I can't see a meaningful benefit. Now in the sketch link it shows a tremendous amount of frame flex before contact. Now this makes sense but does not jibe with what I 'think' I am seeing. But I really think I am missing something.
Sorry to be such high maintenance....
Last edited:
Haf-E
Expedition Leader
This article discusses spring mounts well.
http://www.truckcampermagazine.com/off-road-expeditions/the-overland-fuso-truck-camper
I think that the camper box reduces frame flex and the spring mounts just allow enough flex to reduces point loads from occurring. I don't think you need to allow as much flex as a bare chassis allows - they expect there to be something to be mounted there after all...
http://www.truckcampermagazine.com/off-road-expeditions/the-overland-fuso-truck-camper
I think that the camper box reduces frame flex and the spring mounts just allow enough flex to reduces point loads from occurring. I don't think you need to allow as much flex as a bare chassis allows - they expect there to be something to be mounted there after all...
It's been awhile since I read his build but I don't think these were in his final set up let me go read. The spring here from what can gather is to let springs allow for movement. But it looks like those springs for force to allow movement. I'm not a mechanic. But if you had camper box on that system it be subject to more stress than with the three point system.
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Yeah what he said
Keep reading the next few days of the build diarie. I think it'll become more clear.
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GR8ADV
Explorer
I can see that mounting a rigid box directly along the frame would change the stress pattern along the frame. However that is how they intended them to be attached. So yes it will change it but exactly how they intended. If it is mounted per fuso with several u bolts and wood there arenvirtually no point loads so I am not sure what you are referring to. The only point loads on the frame rails that exist are the ones created by the side spring mounts???
Not sure if I need more sleep or more coffee or more beer. I am starting to feel pretty thick as I am apparently the only one who does not understand this. Thanks for humoring me.