Struts to lift roof - and no lift panels or EMT lifters?

[philos65]

I'm curious if anyone has devised a system based on using struts to lift the roof and a way to lower it without lift panels or EMT tube lifters. I can envision a light block and tackle and come-along system outside at connection plates of the struts to lower the roof. I wonder what the best design for that would be.

For example, I have a 12' long x 7' wide roof on my 80s era Keystone. I have two fantastic fans (10 lbs each?) I'm installing on my roof, along with two 245 watt, 40 pound panels. The roof weighs about 65 pounds, and the new 1" box alulminum rack I built for the panels weighs about 8 pounds. Lights and wiring add some more. 175 or 180 or so pounds.

In principle, you could install four 50 or 60 lb struts to lift the roof, and a small block and tackle/cable/pulley/come-along system to lower it before clamping it to the camper body.

If the idea has validity, how would you protect against wind blowing the roof/vinyl sidewalls over?

I like the idea of a slightly thicker mattress as I'm replacing it anyway.

Anyone tried something like this? What are some "theoretical" problems you can see?

Or maybe this is one of those wild ideas that won't work???

Jeff
Laramie, WY

 

[rando]

I don't think this is going to work. Without the lift panels you have no resistance against shear forces between the roof and the body of the camper. In the first strong wind from the side, the roof will shift sideways, parallelograming (is that a word?) the gas struts. The reason FWC uses lift panels as opposed to cheaper and lighter EMT tube lifter is to provide a 'shear wall' that can resist the horizontal displacement of roof relative to the camper. But even the EMT tube provides some shear resistance. Because the struts are on pivots at both ends they provide almost no shear resistance.

The other thing to realize is that the way the struts are mounted, they provide very little assistance with the firs part of lifting the roof. The struts only push along their axis, when the roof is down, the axis of the struts is almost parallel to the roof, so they are primarily pushing their two mounting points apart, not pushing up the roof. As you raise the roof, they become more vertical, providing more assistance with lifting the roof.

 

[philos65]

So far two issues then.

1. look at the problem of windshear
2. lifting the roof with 180 lbs on it.

Any others? Any solutions to those two issues?

Jeff

 

[DavidGraves]

What Rando said....

The lift panels ARE the walls which make for a rigid structure to support the roof and the fabric sides.

What are you really trying to accomplish ?

Good luck anyway.....


David Graves

 

[philos65]

What am I really trying to accomplish?

I'd love to get rid of interior supports. My lift panels are at the dump, as is the old vinyl siding. Before I put it all back together, I am wondering what's possible.

Jeff...

 

[EDR]

I know you don’t want an internal lift mechanism, but I don’t think I’ve ever seen a soft sided camper without a ridgid and “locked” structure holding the roof up.

 

[philos65]

Hi EDR:

I'm assuming it's inside the camper itself. I'm wondering what a system that doesn't have anything inside might look like - if it's possible. I can see putting in interior cross braces to deal with windshear - simple and a three minute process, after the roof is up. But is there anything anyone can imagine that's more elegant?

Jeff...

 

[EDR]

Sorry, I edited my response after re-reading your initial question.
I did think of another option, similar to what’s used on pop up camp trailers.
Check out “Homebuilt Pop-up roof lift system” on YouTube. Telescoping sections might work for the short front section of the camper.

 

[PaulT]

Jeff,
You could take a look at a mid 70's VW camper poptop by ASI. It might be a heavy lift without strong gas struts as the entire roof goes up at once and a FWC roof is heavier than the smaller VW roof.

Photo here. http://davidsclassiccars.com/volkswagen/35164-1972-volkswagen-riveria-camper-bus.html

Might give you some ideas.
I had a 1978 ASI VW camper. No problems with stability.

Paul

 

[DavidGraves]

Hey Jeff

The lift telescoping posts from a pop up tent trailer involve a fairly complicated arrangement of pulleys and lots of cable and a winch.

All the pulleys and the telescoping corner posts have to be very well anchored.

They can only lift OR lower to a fixed point.

Do you hope to lift a heavier roof than stock ?

There are not many simple and effective options over the original design.

Good luck.

David Graves

 

[JaSAn]

I'm curious if anyone has devised a system based on using struts to lift the roof and a way to lower it without lift panels or EMT tube lifters. . . .The roof weighs about 65 pounds, and the new 1" box alulminum rack I built for the panels weighs about 8 pounds. Lights and wiring add some more. 175 or 180 or so pounds . . .

When I was contemplating replacing my lift panels last fall I thought about some alternatives. One that I think would work is a system similar to what Alaskan campers use: three or four vertical manual/hydraulic/pnumatic rams on the outside with diagonal stiffeners along each wall. How automated you make it would depend on your engineering skills and how deep your pocket is.

I decided that the current system works and to KISS. My only complaint of the current lift panels is the lack of windows (those distorted, kind of clear plastic rectangles in the soft side) to let light in and to maybe see out of; I do miss looking out the front or back without getting a crick in my neck.

jim

 

[jrwdlw]

It is possible to have a lift system that does not use lift panels or tube lifts. I did it years ago when I built a FWC knock-off for my 90 F350. The roof lifted using gas struts on "V" shape lift arms It did take some legs and back to get the lift started, but once is was up about 8", it would go the rest of the way alone. There were four lifts, two on each side. I had windows all the way around with this design. For safety, I had a lock bar I used on each arm, so if the shock failed, roof wouldn't come down.

As far as resisting shear force, once the roof is fully up and the fabric walls are "tight", the fabric is the shear wall. For the roof to rack in any direction, the fabric wall would have to stretch, or the roof would have to lower somewhat. So, as long as the roof can't lower, and the fabric doesn't stretch (or pull out from it's attachment), the roof won't move. I used laminated PVC for the sides, which has absolutely no stretch. Yes, while lifting, you could accidentally push the roof to one side or the other if not careful. I wish I could post a picture, but all of this came about before digital cameras.

 

[shellback]

The lift struts are the cats meow. What a difference they made in raising my roof. I did build the original type lift panels though. Personally I wouldn't depend on just the struts to hold my roof up, or raise it straight. One weak cylinder and the roof getting caddy wompus, could get out of hand. If there was a scissors type device to keep the roof racked straight in addition to the cylinders, I think they would work. I'm surprised neither FWVC or ATC hasn't come up with something to have windows at each end. But as JaSAn stated, the kiss system tends to be the best.

 

[philos65]

Well, I'm making six panels with windows as part of a new sideliner. Four on the sides and one each fore and aft. I have no intention of using the camper in cold weather, so the more ventilation the better. I want windows on three sides of cab over bed. The whole point of owning this thing is to go off grid for as long as I want during winter months.

I'll make a couple assumptions.

The first is that a stiff side liner will resist wind. The 60 lb struts will be enough to hold the roof up. I can test that and modify if necessary. The two 40 lb solar panels will tilt, and serve as minor sails in wind when tilted. Vertical 1" box aluminum inside at the corners would be easy to make and pop in once the roof was up.

Second, I can use the new 1" box aluminum rack on top of the roof and top of the camper lift jacks to lower the rear. Use a strap and loop it from rack to jack and lower the two jacks, bit by bit, side to side. Lowering the front presents a problem. I'll have to think about that one. Maybe a looped strap between the front cross piece of the new rack and an "L" holding from underneath the front corners - ratcheting down to the point where the struts let go.

I suppose a fallback to lift the roof with 40 lb struts is the speaker jack idea - lifting from the inside.

https://www.amazon.com/LASE-201C-Crank-up-Speaker-Stand/dp/B071WSP5X8

Thinking out loud here - all this is thinking out loud - I'm not sure whether to make the roof easy to raise, or easy to lower. 40 lb struts would make the roof easy to lower. Using a speaker jack with the 40s would let me pop in braces at the corners. The 160 pounds of lift would be 20 or 30 pounds less than the weight of the roof.

60 pounders would make it easier to raise, but have 60 pounds of extra lift. That would make the roof harder to lower. I could install a lightweight cable and come-along at each corner and at least start the lowering process til it got to that "magic" spot - 8"? - where the strut would lose its lift.

The 3/4" EMT solution inside the camper is still viable, but I'd rather not have that structure inside. Maybe there would be a way to attach it outside - permanent brackets and put the EMT in the camper when in transit. It would raise and lower on the long sides.

This is all theory of course. I'm brainstorming. Any suggestions/thoughts that explore are welcome! I figure I'm only going to go through this project once, so why not explore options...


Jeff...