Flip top lid!!!

[Franklin]

13 minutes ago, 900SL said:

I'm looking at a clamshell roof now

Can't wait to see this. The curved roof is a great idea, considering the amount of snow you have to contend with now.

[900SL]

.

 

Edited February 21, 2023 by 900SL

[Skipper Billy]

@900SL When we retire and move house, V2 will probably have a motorised curved roof as I can't see a way to automate V1. I have picked up a significant back/mobility issue and this will be essential.

[900SL]

Hope you are OK Billy. If and when i get some time to draw it up I'll send you a copy, might help (or help you avoid any mistakes I may make  )

[900SL]

PS I got the idea from a wheelie bin lid...

 

[900SL]

A quick google turned up this , from Germany

Only problem I can see is the neighbours having a stroke thinking the travellers had set up camp

[R26 oldtimer]

3 hours ago, 900SL said:

I'm looking at a clamshell roof now

Should be possible to open and close this with linear actuators or a screwdrive

Basic sketch I knocked up just to start to get a handle on the basics

 

 

I'm toying with a similar idea, but why split the roof in half? It could rotate as a single piece to the side.

[900SL]

9 hours ago, R26 oldtimer said:

I'm toying with a similar idea, but why split the roof in half? It could rotate as a single piece to the side.

I see a number of advantages in a split roof design, namely:

Lighter weight each side

More flexibility on opening - if imaging one side only you only open that side, so keep some shelter

Easier to balance - I am looking at using garage door springs between the radial arms to offset the roof weight (easier to open and close)

Against this is increased complexity of roof and roof ridge flashings

[900SL]

V3, without radial arms

Roof made from stressed skin ply with stiffening ribs and insulated to get a light weight panel (helps being a structural engineer..) and single ply membrane waterproofing

Runs on ply glu-lam end plates, bent to matching radii

Teflon strips for bearing runners

Roof positively secured into side face rebates for wind uplift

 

Roof radius flattened to reduce force needed to close (slope F cos theta ) 

 

 

Edge detail above. Glulam radial bearer is routed and fitted with galvanised light gauge channel insert for roller track

Might be easier to run the ply laminates horizontal, easier to bend to required curvature, glue, clamp and allow glue to set. 

Or keep as-is and cut curved sections of ply to accurate curvature, no need for bending jig 

 

Edited February 21, 2023 by 900SL

[900SL]

If anybody is interested, my initial calculations indicate that you could make a stressed skin shell up from 40 x 75 ribs at 600mm centers and 8mm structural ply top and bottom spanning 2.4m.

Deflection under snow load mid span is around 6mm

Weight of each roof panel is around 40 kg plus membrane, closing force around 20 kg

[Adaaam75]

This is a viable alternative to a sliding roof and will not only take up less space but also looks more compact and structurally sound.

 

[900SL]

So I got to thinking those overhanging curved roof guides could be used to provide more interior space. So I angled the ply panel walls outwards so I can have shelves/worktop/storage  running along the sides

The left hand elevation shows the end wall, door framing, and curved glulam roof guides

 

The right hand section is midspan. The moving roof panels sit above the fixed lower roof panels and slide open over the lower roof. The left hand side of the roof is shown open in both cases

 

Again this is rough work, I've got to tidy this up quite a bit and sort out all the weathering details

   

[Mark2022]

On 11/02/2023 at 09:49, Skipper Billy said:

Hello Mark

Just built the once but I altered the half height door to full height after a couple of seasons of use - the bending and crawling on my knees on a frozen surface wasn't doing my old back any good and it was structurally strong enough to be OK with a full height door. It made life much easier.

The roof is covered in EPDM - very easy to use, completely waterproof and still in good nick 8 years on.  ClassicBond® 1.2mm EPDM Rubber Roof Membrane | Rubber4Roofs

The handles were sealed inside and out with Sikaflex 291 - not a single drop of water has ever passed even with the grandkids using it as a climbing frame !

Good luck!

David

 

 

Hi again David, Can you possibly describe/explain the roof design in more detail: What material/wood size used (9mm OSB?) and how you created the apex/v shaped hang over; how it connects and what material? Also, what sort of weight are the two sections would you guess? Do you think having a 1.6m x 1.8m version would make  the  roof section too unwieldy?

Thanks.

[Skipper Billy]

8 hours ago, Mark2022 said:

Hi again David, Can you possibly describe/explain the roof design in more detail: What material/wood size used (9mm OSB?) and how you created the apex/v shaped hang over; how it connects and what material? Also, what sort of weight are the two sections would you guess? Do you think having a 1.6m x 1.8m version would make  the  roof section too unwieldy?

Hi Mark

The roof panels are 9mm Sterling board over a 1" x 1" wooden frame. The panels are then covered in EPDM. The two panels meet fairly flush when closed. I made an inverted V shape strip to cover the gap from two pieces of ~75mm x 25mm wood planed to give the correct angle of the V (glued and screwed together). This was then covered in EPDM and fixed to the Western side panel by screwing through the roof panel into the V strip from the inside along with a good bead of Sikaflex 291. This means the western panel has to be opened first and closed last. I chose to seal it to the western panel as thats where most of our weather comes from.

Each complete panel weighs about 9kg - the western one a bit more and the Eastern one a bit less.

I would expect 1.6 x 1.8 would be perfectly maneagable if you are reasonably strong/fit - you could decrease the weight by using polycarbonate instead of Sterling board as most of the strength is in the 1x1 frame. EPDM is surprisingly heavy!  I am 64 and I picked up a significant back injury last Nov (which is why I havent posted much in the last 6 months) but with care and good technique I can still open and close the roof. 

There are some detail photos and video of the sealing strip and videos of it opening and closing on the previous page in this thread.

The only downside I can see with this design is that it is almost impossible to motorise it to open and close remotely.

Feel free to ask any questions. It has worked really well for me and has never let a single drop of water in despite >100mph winds, biblical rain and temperatures down to <-20 degrees.

 

[900SL]

I'm onto V3 now, a single panel stressed skin ply roof with torsion spring counterbalances each end

Size is 2m x 2.4m internal. Roof weighs around 50 kg max. Any resemblance to a wheely bin is accidental

[900SL]

Has anybody ever used a 'torsional spring' in a counterbalance mechanism?

This seems fairly straightforward in principle (famous last words..)

The roof exerts a torque of around 30 kg-m each end when opened 90 degrees.

I used an on line torsion spring calculator and this estimates a 16mm wire, 100mm diameter and 8 coils from memory to give a resistance of 30 kg-m at 90 degree twist

Some rough sletch section to demonstrate the principle. Steel plates screwed to wooden framing, M20 shaft to outside radial arms, spring assembly inboard of radial arm.

I'm not a Mechanical Engineer so no idea if this is how you do torsion spring assemblies, welcome any feedback. Or I could just use a counterbalance weight, but that's too simple  

 

 

[Swoop1]

I like the thinking behind that solution👍

I have absolutely no idea if the thinking and maths is sound however😐

[AstroMuni]

On 06/08/2023 at 20:53, 900SL said:

I'm onto V3 now, a single panel stressed skin ply roof with torsion spring counterbalances each end

Nice one. The bottom right image seems to show the curved roof folded downwards?? I am trying to figure out if I have understood it correctly.

Edited August 9, 2023 by AstroMuni

[900SL]

4 hours ago, AstroMuni said:

Nice one. The bottom right image seems to show the curved roof folded downwards?? I am trying to figure out if I have understood it correctly.

Indeed so. The arches each end could be hinged along that line and fold down once the roof is opened