Bar out over the side/rear from the roof

[lager911]

Not to disrespect anyone but this is a bad idea where otherwise this is a simple cantilever beam problem.

Jim

the bad idea is still where i am on this as of now. I was treating it like cantilever beam. metal beam supports the weight as tested so it is more of a can the connection points and roof corner support with out breaking.

[Guest]

the bad idea is still where i am on this as of now. I was treating it like cantilever beam. metal beam supports the weight as tested so it is more of a can the connection points and roof corner support with out breaking.

The roof (trusses) and walls are not designed to handle the dynamic loading as stated by many of our engineers where this could result in a serious injury or worse. I would not say its impossible where you could run another beam down the back to attach to the frame of the trailer for the compression forces on the rear wall. For the rest of the beam (if designed for no buckling, high I), this would have attachments to the roof that are in tension. This mounting would need to contact every truss from the back to front of the rig since we do not know the actual strength of the trusses ( dimensions, materials used etc) which are designed for compressive loads such as snow, walk on etc.. So the roof top beam could be designed as another truss and ran full length of the trailer with the vertical support beam at the rear to the frame...not the bumper.

Also this is just taking into consideration forces in the Z direction where depending on the activity there could be forces in the Y direction as well. You would be ok in the x direction with a truss like beam running full length of the trailer.

I still would not do it.

Jim

[Cate&Rob]

Not to disrespect anyone but this is a bad idea where otherwise this is a simple cantilever beam problem.

Jim

Hi Jim,

Agreed that this is a simple cantilever beam. The concern is holding the inner end of the beam down and the mid point of the beam up. The roof trusses are designed to support loads in the downward direction, not the upward direction. The wall edge may or may not handle the point compressive load of the beam center point support. A "free standing" structure as Keith Yoda suggested, attached to the RV only for stability might make more sense.

Rob

[TucsonJim]

= Don't do it!!!

Sorry

[Guest]

TucsonJim Nice Jim.

Partial differential equations.

Just don't ask me to do this today. We use those fancy computer models. I bet you EE guys just loved those imaginary numbers.

Jim

[lager911]

I wish I had clarified this earlier in the post and it may not make a difference. The only exercises I would be doing on this are dips and pull-ups there actually is no swinging motion I use rings instead of a pull-up bar or dip bar because they add a little bit of instability and are genuinely more convenient to set up. Which is a really funny statement considering this post.

[Guest]

Hi Jim,

Agreed that this is a simple cantilever beam. The concern is holding the inner end of the beam down and the mid point of the beam up. The roof trusses are designed to support loads in the downward direction, not the upward direction. The wall edge may or may not handle the point compressive load of the beam center point support. A "free standing" structure as Keith Yoda suggested, attached to the RV only for stability might make more sense.

Rob

Agree Rob,

Rather than a beam across the roof, another truss could be used in place of the roof top beam and made of aluminum or better yet titanium. I still do not support doing this even though its interesting.
Jim

[Guest]

I wish I had clarified this earlier in the post and it may not make a difference. The only exercises I would be doing on this are dips and pull-ups there actually is no swinging motion I use rings instead of a pull-up bar or dip bar because they add a little bit of instability and are genuinely more convenient to set up. Which is a really funny statement considering this post.

I wish I could still do a dip or a pull up.

Jim

[Yoda]

My problem with these is the setup part and storage in a small 21bhe. Otherwise though I like a lot of these!!

You could add one of these to store it in. Mount it to the rear bumper or frame. https://www.buyersproducts.com/produ...arrier-kit-576

[Yoda]

= Don't do it!!!

Sorry

Your going to give me nightmares
Been 55 years since...... well lets say not my favorite or best class......but I did pass. HP saved me with the 21 model - I gave up the slide rule and never looked back. Still have 2 though though linear and round one but don't ask me to work one even though I took a class to learn.

[lager911]

You could add one of these to store it in. Mount it to the rear bumper or frame. https://www.buyersproducts.com/produ...arrier-kit-576

Or maybe just store it in the rear bumper? I actually have something similar to that for my waist hose attached under the rear bumper so my rear bumper is empty.

[Country Campers]

lager911

This has been and interesting post to say the least. It seems that you have opened a can of worms for the "engineers" to dust off some of the rust accumulated from being retired. I was really hoping this would get the green light some how but I am not sure that the effort will be worth it. I am still holding out on a little hope though.

Brian

[lager911]

lager911

This has been and interesting post to say the least. It seems that you have opened a can of worms for the "engineers" to dust off some of the rust accumulated from being retired. I was really hoping this would get the green light some how but I am not sure that the effort will be worth it. I am still holding out on a little hope though.

Brian

I'm up for keeping the discussion going. How about I promise not to try it unless Cate&Rob , TucsonJim and Guest all give me green .

So 1. Need to address compression at the corner both material failure and whole rear wall.
I think I read Jim recommend a support connected to frame not bumper. so what if I added another beam similar to the existing one vertically at the wall connected to the frame / bumper. This would alleviate any compressive force on the actual back wall or corner.
2. The trusses are not designed for an upward pull. I think adding two beams to create an A-frame on the end of the part sticking out wouldn't be too much to ask. Those would then just go to the ground to create a support. The connections on the roof trusses would then only need to be enough to hold it.
3. The two beams that make the A-frame support could be telescoping and stored in the rear bumper during travel.

This is starting to become a good bit of setup each time I want to use it which is what I was trying to avoid. But still way less setup than trying to set up a portable freestanding stand.
All the Best,
Law

[howson]

I wish I had clarified this earlier in the post and it may not make a difference. The only exercises I would be doing on this are dips and pull-ups there actually is no swinging motion I use rings instead of a pull-up bar or dip bar because they add a little bit of instability and are genuinely more convenient to set up. Which is a really funny statement considering this post.

You've got the engineers here buzzing and writing techno babble--easy to tell they are quite happy getting immersed in "their world". I can just imagine the smoke emitting from their slide rules and scientific calculators. lol

[Guest]

lager911 Don't forget Yoda. I believe he is a civil engineer.

Jim