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This whole thing was a University project so documentation is a bit spotty.
I designed a robust chair, it survived many a party (unlike most fragile chairs I've seen) and the principle could be applied to any household furniture.
I've included a step by step of how the basic structure goes together (along with an IKEA type instruction book).
But the best bit is the video of me putting together a whole chair.
- Enjoy
I designed a robust chair, it survived many a party (unlike most fragile chairs I've seen) and the principle could be applied to any household furniture.
I've included a step by step of how the basic structure goes together (along with an IKEA type instruction book).
But the best bit is the video of me putting together a whole chair.
- Enjoy
CBC - manual 2.pdf(1684x2384) 296 KB
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Signing UpStep 1Basic Structure
This will take you through making the basic structure, you can make whatever you want out of it. The pictures (and notes) do most of the explaining.
The first layer will need 3 strips of card, one longer piece to create the zig-zag and two 'sandwich pieces'
Mark out and score your longest piece at 42mm intervals on each side, make sure to stagger the lines so that when scored it will fold up properly (fig.2)
Take one of your other pieces and mark out and glue it (fig.3)
Now carefully glue down the zig-zag piece, you may need to use pins or tape to hold it while it dries.
After about 10 minutes you can glue the second sandwich piece on top.
Use something heavy to weigh it down and make sure it all sticks. (fig.4)
You can continue to add as many layers as you need (fig.5)
you can make this stuff in big sheets and cut it to the right size later, or you can cut out the shapes you want and build them up layer by layer. (like i did)
The first layer will need 3 strips of card, one longer piece to create the zig-zag and two 'sandwich pieces'
Mark out and score your longest piece at 42mm intervals on each side, make sure to stagger the lines so that when scored it will fold up properly (fig.2)
Take one of your other pieces and mark out and glue it (fig.3)
Now carefully glue down the zig-zag piece, you may need to use pins or tape to hold it while it dries.
After about 10 minutes you can glue the second sandwich piece on top.
Use something heavy to weigh it down and make sure it all sticks. (fig.4)
You can continue to add as many layers as you need (fig.5)
you can make this stuff in big sheets and cut it to the right size later, or you can cut out the shapes you want and build them up layer by layer. (like i did)
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I can't work it out - is that "meta" or "über" corrugation?
How does the triangular corrugation add to the structural integrity of the chair. Of course it will help resist sheer (or is it lateral) force, but it strikes me that the primary challenge in furniture building is downward force. So my question is, will the triangular corrugation improve the chairs ability to hold weight, or is the vertical and multiple layers of cardboard in the arms the only weight bearing design feature?
You are right that in a chair probably largest loads are downward. So what vertical corrugation does is increasing the stability of the design. It increases what is commonly called Moment of Inertia. Take a sheet of paper and stand it on edge. It will support no weight. But corrugate it, or transform into a vertical tube, and it will be a lot stronger.
Also: for strength, the amount of material is no more important than the placement of such material: for a sound (and not overweight) structure you want to put the materials under load as separated as possible. Thus, what corrugation also does is to separate one flat paper from the other.
There is a video where aircraft designer Burt Rutan shows that a mini bridge made of two lateral supports and a horizontal piece of, say, 1 inch rigid (insulation) blue foam cannot hold the weight of a single house brick. Equally, two layers of a thin fiberglass+resin laminate cannot support the brick either. But if you epoxy glue one fiberglass layer at each side of the foam (a sandwich structure), the assembly (FG-foam-FG) will support, without even bending, the weight of many bricks.
The structure is strongest at resisting force in the arrangement I have used here. Simple downward compression force translated vertically, running the direction of the corrugations. It obviously doesn't work well in tension which is why I had to use tubes for the crossbeams.
You can get adjustable hole cutters, similar to your circle cutter, for drills - though I don't know how well they'd cope with the thicknesses you're working with here.
A couple of questions - how did you figure your seat-tubes layout? And is it as comfy as you think/thought it should be?
I used anthropometric data from "Architect's Pocketbook" It had average seat heights and angles etc.
Unfortunately I couldn't find similar info online, I would just find a chair whose dimensions you like and measure that.
As for comfort it's not great, If done again I would use 6 smaller tubes for the seat, instead of 3 larger. But throw a cushion in it and it's fine.
Just off the top of my head, keeping 2 large tubes (one at the front, for comfort on the backs of your knees, and one at an appropriate point to support the lower back) might be an idea.
Architects pocket book has some useful basic stuff, but also has standard door/window sizes, prevailing wind conditions across areas, standard sizes in paper/stationary, common bugs likely to eat your house, loads of other random stuff.
(basically a bit of everything)
Knowing my scatterbrain self, I now definitely want the "Architect's Pocketbook" (and given the variety of projects on Instructables, I'd suspect your explanation will cause a bit of a run on it) ;-D
http://www.fas.harvard.edu/~loebinfo/loebinfo/Proportions/humanfigure.html
http://en.wikipedia.org/wiki/Ergonomics
http://www.valuecreatedreview.com/design.htm
(This last reference links to a few free useful PDFs on standards.)
But measuring existing furniture should be a safe way to go.
And a bit of memory-jogging doesn't go amiss, either. To that end, your bracketed comment reminded me of "The-Blueprints.com", so I dug out an old link, had a search on the site, and found some chairs on:
http://www.the-blueprints.com/blueprints/misc/furniture/
If nothing else, they'd save 'you' the measuring of those particular chairs - though it may still be necessary to do some maths to figure averages you can transfer to your own design(s).
The site seems mainly 'dedicated' to "Planes, Trains and Automobiles", but each of these tends to have at least one chair...
And they have a 'Humans' section, so you can sort out proportions.
You'll need at least a free account to do much of anything (basically, downloading as graphic images, via the right-mouse-button), but a paid-for account will let you actually download usable files.
My only problem is that the pictures you download don't have measurements on them, so you have to know at least one dimension of whatever it is, to be able to scale it properly.
That's odd - I just downloaded this Adirondack Chair - both by right-clicking AND via the Download button - and I don't have a paid-for account, just the free one (or am I mis-interpreting your problem?):
A kind of furniture that I might seriously consider using to furnish a weekend house. Congratulations.
A
When I use cardboard tubes to make telescopes, I paint them inside and out with a 50:50 mixture of carpenter's glue (Titebond II) and water (and occasionally some water-based paint mixed in), making them really wet and letting all this soak in. Two or three coats like that, and the result is a very nice and hard tube that can be used outdoors (though I wouldn't want to keep it out in the rain--Titebond II is water resistant but not waterproof (Titebond III would be better, but it's more expensive)). You can sand it, too.