Slide out mechanisms?

[LukeH]

Hello all you adventurous self builders.
I haven't got to the camper part of my build yet as the cab extension still requires quite a lot of welding, and the truck is 5 hours drive away, so I have to do it in fits & spurts.

But that doesn't stop me planning and scheming while I'm at work ;-) This is probably a bad thing, as I'm hatching all sorts of far flung ideas, and I'm using my office (and CAD) time to explore and validate them.
The current camper body design idea involves not only a slide, but also a hard sided lifting roof. When down, the roof will retain (and therefore lock) the slide. When up, it will give an extra sleeping space like the Unicat offerings.
The big difference is that I'm on a tight budget (aren't most of us?) and the panelling is certainly going to be recovered from an old refrigerated semi trailer. The lift will be with rigid chains rather than hydraulic (I couldn't get my head round synchronising 4 hydraulic rams), so that's easy.
But for the slide, I've looked at all sorts of systems, and I can't invent or find anything better/stronger/more space efficient than the HWHcorp Universal slide out (USO) straight in – straight out system.
The problem is that HWH Europe wants an arm and a leg and half my mortgage for a new USO system |-(
I would like to look for one from a broken/dismantled American RV but I can't think of the keywords other than “RV breakers yard” or “RV scrapyard” and they don't turn much up.
SOOO, my request to you US residents; first of all do you have any addresses of breakers yards I could try.
And does anybody know anybody who's connected to HWHcorp? The guys in the US refuse to give me a price, my phone number must flash up “Europe” (even masked) and they send me directly to their European importer. Could someone find out how much the USO kit including pump and seals for a 14 foot x 6,5 feet slide (stroke 24 inches, weight approx 600 pounds), delivered somewhere on the East Coast would be?
Pretty please?
Many thanks,
Luke

I promise there'll be a build thread, but for the moment there aren't enough pictures to fill it, and progress is slow. Here's where it's stopped and waiting:

 

[18seeds]

Hello all you adventurous self builders.
I haven’t got to the camper part of my build yet as the cab extension still requires quite a lot of welding, and the truck is 5 hours drive away, so I have to do it in fits & spurts.

But that doesn’t stop me planning and scheming while I’m at work ;-) This is probably a bad thing, as I’m hatching all sorts of far flung ideas, and I’m using my office (and CAD) time to explore and validate them.
The current camper body design idea involves not only a slide, but also a hard sided lifting roof. When down, the roof will retain (and therefore lock) the slide. When up, it will give an extra sleeping space like the Unicat offerings.
The big difference is that I’m on a tight budget (aren’t most of us?) and the panelling is certainly going to be recovered from an old refrigerated semi trailer. The lift will be with rigid chains rather than hydraulic (I couldn’t get my head round synchronising 4 hydraulic rams), so that’s easy.
But for the slide, I’ve looked at all sorts of systems, and I can’t invent or find anything better/stronger/more space efficient than the HWHcorp Universal slide out (USO) straight in – straight out system.
The problem is that HWH Europe wants an arm and a leg and half my mortgage for a new USO system |-(
I would like to look for one from a broken/dismantled American RV but I can’t think of the keywords other than “RV breakers yard” or “RV scrapyard” and they don’t turn much up.
SOOO, my request to you US residents; first of all do you have any addresses of breakers yards I could try.
And does anybody know anybody who’s connected to HWHcorp? The guys in the US refuse to give me a price, my phone number must flash up “Europe” (even masked) and they send me directly to their European importer. Could someone find out how much the USO kit including pump and seals for a 14 foot x 6,5 feet slide (stroke 24 inches, weight approx 600 pounds), delivered somewhere on the East Coast would be?
Pretty please?
Many thanks,
Luke

I promise there’ll be a build thread, but for the moment there aren’t enough pictures to fill it, and progress is slow. Here’s where it’s stopped and waiting:

5 star rv in henderson colorado usa.

 

[Victorian]

Wow! I hope you know what you are getting yourself into!
I did this full time at Unicat for a while... Huge, just HUGE!

You better make sure to get the mechanism working correct! It may looks and works fine in a nicely heated and level (!) shop. But being outside on uneven ground it's a different story! Not even talking about weather proving that whole set up!

Anyhow, I wish you good luck! Please keep us posted on your progress.

 

[LukeH]

Thanks for the tip-off 18seeds, I shall investigate further.
Victorian, I hear you, and I am very interested in your comments (and in your experience).
Obviously you can't give away all the Unicat trade secrets, but I'm sure there's a way I can squeeze more information out of you ;-)
Why so huge? It's just a box on a box; did Unicat encounter that many problems? If so, are they selling a product that has inherent design problems?
Your comment about the alignment surprises me, surely the whole point of the torsion free mounting is that the box is not subjected to deformations, therefore in theory the mechanism will work regardless of chassis twist. I don't like the Unicat chassis system, it's statically indeterminate, and IMHO does transmit some deformation to the box (not necessarily twist; a lorry chassis is very floppy)
I'm thinking of using rigid push chains for the lift, which can be synchronised mechanically rather than hydraulically, and with a worm drive motor are self locking. They also have the advantage of being very tolerant of misalignment. (or perhaps in my case, poor assembly)
OK it means I have tubular transmission shafts going around the upstairs bed area, but that's easily hidden in a casing.
So I think the mechanism's easy. I think.
Mind you a recent post in Basingranger's build thread has got me thinking about synchronised hydraulic rams again…
I reckon the biggest challenge is sealing. I plan to use four blade wiper seals from the refrigerated lorry industry; does anyone know if the wiper seals from the RV slide outs are better/worse?
The seal will only be at the bottom of the roof section, thus keeping all the inside clean.
But on the long sides that makes 5.3 metres of seal! There's no way there'll be enough force to keep the seal in contact in the middle of that length!
On the Unicats I see a sort of guide thing or two up the sides; does that have a piece that links the sliding panel to the fixed, to keep the seal in contact?
If so, that makes an air gap in the channel itself, how do they deal with that? For closed position I have thought of a sort of locating pin and socket affair within the thickness of the walls. For open, my slide guide is on the inside of the sliding section, with the adjustable pin on the top edge of the fixed wall.

However hard the sealing is, it's not going to be perfect. And what's more, during opening the box is going to act as a whopping great bellows, and any dust in nooks and crannies will be woken up and sucked in.
To counter that I plan to put a modified Trav-L-Cool in the roof, sucking filtered air into the camper. That should create a slight positive pressure inside the box, hopefully keeping the dust out. I just have to regulate the lift speed so the volume increase is slower than the air flow rate of the unit.

As you can see I have way too much time to think about it and am just desperate to get on with it.
I would welcome any comments, criticisms and suggestions that anyone has on this concept.
Many thanks
Luke

 

[Victorian]

Think about camping in freezing temperatures. How will you keep the seals/moving parts from freezing up and possibly ripped apart?

 

[LukeH]

Now there's a point.
Good one Victorian, I presume you're asking the question because you have seen the problem show itself in your professional experience.
Clever way of not giving away secrets and not exposing yourself to any sort of follow up.

So on reflection, it's quite clear that in a confined space with my delightful Italian wife (MMMM Pasta!) there's going to be a lot of humidity. Even with 60mm thick refrigerated lorry panels there's a danger of condensation, especially down at the four blade wiper seal.
My first thought was to stick that amazing anti-insect tape all the way round where the seals rest. Nothing sticks to that stuff, not even ice.
But then you'd be sliding a block of ice down the side of the camper to close it.
So the two levels (open and closed) where the wiper seal rests will be taped with heated lagging tape. I've seen self adhesive wrapping tape with a heater wire in it on mission critical plumbing in the past; I have absolutely no idea where to source the stuff though. Ideas anyone?
When parked the tape would not be energised, if ice forms it will actually help the weatherproofing. A few minutes before lowering the roof I would have to remember to energise the tape, and after a calculated time (mass of water x latent heat of fusion x temp ext for example) I would be able to lower the roof.
Waddyareckon?
D'oh! If Uniknow who are watching this I've just given away a cool idea! There are plenty more where that came from guys, gissajob please.

I'm looking forward to your next question/problem.

Cheers
Luke

 

[part time nomad]

Thats quite an interesting motor, Volvo FL6 4x4 I see this is an old thread, do you still have it?

I worked at a Volvo main dealer in the 80s but never saw a 4x4

 

[LukeH]

Hi, yes I do, I get to go and work on it only two or three weeks in the year so progress is slow.
The torsion free subframe is on.

And the second cab is grafted securely in place:

Having terrible trouble with the cab tilt, the mechanism I found from a double cab Renault just doesn't have the throw, and if I fit it so it has the throw it isn't stront enough to lift it. I'm probably going to have to just buy a whopping great telescopic ram off a tipper body.

I get to go and play with it next week. Yippee!