Designing a better dome hub
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- čas přidán 13. 10. 2018
- This is the first of a new series of videos about improving on existing designs. Geodesic dome hubs are many and varied but I think I can design something better. The brief would be to have fewest number of unique parts, inherent strength, low cost to manufacture or make and something that is as flexible as possible so the hub can be used in lots of different ways. In this video we look at whats currently on the market, rough draughts of the new design and some early concept drawings. Later I'll make videos of prototyping, product testing and hopefully full production.
If you are interested in becoming part of this project please feel free to get in touch, I could use some advice on 3D printing prototypes, injection moulding etc. Thanks for watching - Jak na to + styl
Looks very promising. The flexibility of your design is genius. I hope it comes to fruition.
Very cool. It’ll be interesting to see how this progresses. Thank you.
This design is great! I've thought about a lot of the same drawbacks of other methods that you mention in the first part of the video and completely agree that there is a need for a product like this.
The way that each wing can rotate around the strut axis in order to meet its corresponding neighbor strut's wing at the midway plane is really great. The struts being bolted to each other rather than to a separate center hub prevents unwanted shifting and the placement of the top-left wing hole down and bottom-right wing hole up puts them into alignment with each other and keeps the strut from being offset from its axis. I'll search for a producer in asia that we could work with. Again, great idea, Paul.
Molten Aluminum cans are my first build thoughts. Thanks for sharing.
For temporary use in non-load bearing structures, this looks great. I worry about the shearing forces that would be exerted on the screw and bolts, so I wouldn't trust it to hold up anything living, or heavy. But as part of a temporary greenhouse or tent shelter, it'd do just fine.
If I were to fabricate something like this, I'd probably go with sheet metal. It'd be like making a hinge. Cut a rectangular piece , round one side and drill a hole in the center of that round. This is the hole that bolts to other hub pieces. Other side, cut down the midline, and off to one side. Roll up the tongue, mirror half the parts so the tongue rolls the other way. Screw a pair to a beam, maybe with a washer on the head for good contact. Heck, invest in tooling, and punch the blanks out with a press.
I agree with the others who left a reaction. It looks very promising. Looking forward to further progress in this project.
Looking forward to seeing the prototypes.
Looks promising, looking forward to being able to purchase some of these for a small proof of concept, then moving on to something larger.
Ingenious. While you mentioned it, what you did not show clearly is that each hub section is in two conical sections, with 'ears'. I would suggest having interlocking teeth between the two conical surfaces to prevent it from rotating once attached to the strut. You could also make the wider conical portion have a tubular section into which the strut/dowel could be inserted, with a hole in the side for inserting a screw into the strut rather than using one screw to extend through the two conical sections into the strut. You would then use a bolt going from the narrower section (top) into a thread cut into the larger (bottom) section. Alternatively, you could use a nut on the end of the bolt inside the lower section. These could also be 3-D printed using carbon-fiber filament.
That's sheer genius. I see no reason why this would not work as you intend. You're right, it would be great to have universal hubs with more strength than what's available now. I hope you can make prototypes and test it!
I think it best to add teeth or gears if you may. Where the upper hub and lower hub won't slip once tighten together. The bolt should be an Allen wrench bolt in order to easily tighten and loosen the bolt in a confined configuration.
Brilliant! This is totally visionary and got me thinking outside the box. I'm thinking about how it will connect with various hollow strut materials like piping or PVC. Looking forward to your prototype. I'm in the process of building a small model as a guide to a much larger version. Hopefully get my kids involved but unlikely. Consider patenting your idea.
Love this, really a great concept😎
Brilliant design concept.
I am so intested yo see how this goes. I had to delay my dome building due to flooding in the area (bought your plans a while ago) and this looks like it might be a tad easier for my poor woodworking skills! Good luck!
Brilliant design
Brilliant!
Exactly whant i'm looking for, hope you do or did it !!!
Excellent!
Another idea -- what if you had triangular panels with the wingnuts integrated on the corners ? Then we'd get not only hubless but strutless.
I like your concept. I hope the angle locking system is strong . Keep up the great innovations.....
I only just got to see this video, and it took a while to assimilate in my head. I love a good puzzle.
It seems to me that if all the bolt holes are the same angle and distance at the end of the struts, then the multiple strut assemblies will only work for identical angles of hub struts joining at each hub. With one project, a 4 frequency summary of panels looked like this.
Panel data summary
Area Perimeter Side 1 Side 2 Side 3 Ang13 Ang23
1.09 4.81 1.52 1.52 1.77 54.33 54.33
1.35 5.31 1.77 1.77 1.77 59.92 59.92
1.42 5.44 1.77 1.79 1.88 58.80 57.53
1.56 5.70 1.88 1.88 1.95 58.72 58.72
1.65 5.85 1.95 1.95 1.95 60.00 60.00
.. so we have angles between 54.33 degrees and 60 degrees etc
Michael Sowdal mentioned that the conical shape was going to require special casting or tooling, which makes sense. When you think about it, if you abandon the need to get the end of the struts close together, what you have here is a big hinge, with a hinge pin and two "flaps" at the end of each hub.
In fact, if you abandon the idea of the end screw to hold the components together, and just have a rod projecting from the end of each strut, the two "ears" are just the opposite sides of a hinge.
Its been a while since I fiddled with domes, so I may be missing something. I'll do a bit of a drawing over the next 24 hours to clarify my thoughts a bit.
Nice design looks like it will be a hub for a flat plane intersection, but I guess you could get some "dish" via flex or distortion if needed. Seems ok for non heavy duty applications or low wind areas.
I love it!
I find this a great design. I hope we can see this as a finish product availablein ebay soon
brilliant!
May peace be with you.
Design looks ok , but correct me if i am wrong ( i work 3D only in Sketchup :-) so far) , those 3D schematics you made works only if those strut elements are in straight position - flat , not angled for dome shaped structure.
Design lack at least 1 joint element so that struts can make angle in relation towards this roughly looking hub.
Friend recently suggested me those dome structures and since i like challenges so i am conducting little research because dome structures are rather none commercial appearance in Croatia.
Friend is carpenter and have experience in many wood works and constructions.
I do have like Tesla some schematics in head but Sketchup is rather something you really need to give much attention like every patents which were made, so closest to perfection is required , nothing less may pass.
May peace stays with you.
Very nice design...!! Since the transfer of load from Struts to the Hub is thru that one screw, it could prove as a failure point... Just bumped into your video... will look for your latest developments...!!!
the zip tie hub is super strong.. best idea imo
Wow, you are a hero with that ability to come up with most practical design concepts. And am in awe at your abilities to best utilize that Google Sketchup. You are like the Mark Knopfler of geodesics, lol. Most impressive.
Have you considered uploading that onto the Thingiverse 3d printing based website? You probably have.
I've been printing a few small dome connectors from that site just to tinker with and try to make sense of them, though admit to being dyslexic along with a parkinsons/ms variant, and math hurts my brain, lol, though would be interested in that one you just created right there.
Also, a design that makes best sense for creating home additions with, such as for use with flat walls that have sliding glass doors on them. It's a matter of geometry for those segments that are meant to adapt with a flat wall surface area. And even perhaps dome additions that even can wrap around corners of square shaped housing structures.
And adaptations for standard window frames that could work well being windows on domes, rather than just triangular shapes of windows to consider.
Thanx for sharing your Vulcan knowledge in such a open source-based platform as this.
Have a super day. \V/_ 🇨🇦
Thanks for your kind words, I'll definitely put some files together for thingiverse, as soon as possible.
After reading through the comments and digesting all the "coplanar" comments, I can understand the confusion. The various hub configurations at 7:50 look somewhat coplanar, but I can imagine these flexing to create dihedral angles. I can visualize the center "void" of the hub increasing/decreasing in size and the "ears" rotating axially to each other. Wouldn't these need some sort of keying/knurling/toothing to prevent undesired axial rotation of the "ears" once the proper angle has been acheived depending on dome frequency or hub angles. Any external loading may deform the dome. Depending on the friction of nut and bolt fasteners may be insufficient to prevent warping of the hub angles.
very good design
Your tube hub is a wonderful design and would work perfectly but the tooling to produce it would require casting or injection molding, both very expensive. I'm going to assume you intend to improve the production of a greenhouse structure rather than the construction of a dwelling. The use of tube frames has the big issue of covering the dome in a manner to seal it as the tube frame must be covered after construction unlike your current method that allows each frame to be covered individually (your current method rocks!). I propose you might work to remove the actual frame member and mold panels of polycarbonate to the required shape to allow them to be gasketed and riveted in place. While this would require a vacuum or strip heater forming process and limit the size of dome produced it would make the construction and sealing a snap. Please keep the good work coming.
That's a good idea! I had a similar idea for making molds for pouring Aircrete dome blocks.
Great Idea, Work, Contribution and Design Show, how to ease the Footprint of Humanity on our Host (Planet Earth).. Universal Geodesic Hub Joint..
This appears to be a good workable joint design.
I would like to add to Guillery's comment. In addition to making the units able to pivot, each unite should be attachable to a hallow pipe. PVC plumbing pipes ,even metal ones, are hallow and tend to be the most commonly used in DIY pyramid and geodesic dome construction. Screwing through the top section into the side only works if the side is a solid soft enough for the screw to get a firm "bite" into it.
Best hubs are from Natural Spaces Domes. They are very strong and are engineered for up to 80 foot diameter domes.
Terrific idea! Am wondering where/how the joint takes load from an exterior covering considering that trusses must take their loads at joints. Was wondering if some sort of flanged or capped ring in the z dimension could provide that.
This is good design for temporary and light /without heavy load. I'm a bit concerned how strong to withhold load and aging will be the welding of ring to a semi conical base.
Great design, I wonder how it would hold up. Have you tried doing a paper unfolded model of it? Awesome work! Very clever!
I like that. I wonder if you could use that recycled plastic sand mix? It seems fairly ridge.
Amazing thank you so much they'll definitely make a wooden that's would fit inside PVC tube this Crew 2 security on The chew would be Allen key that's could be worked on an angle this will push the two sides out word
Cool
I like the simplicity of the proposed attachment, however, there is a dead space created at the centre of each junction due to the design of the attachment. In the case of a three way junction this is a reasonably small triangle, but for both the pentagonal and hexagonal junctions the dead spaces would amount to substantial pentagons and hexagons, respectively. To ensure the weather integrity of any geodesic dome created as a structure using the suggested attachment would require some suitable solution to deal with the resulting holes at each hub.
The size and shape of the void changes with the number of brackets in the ring. Its not like a circular hub where the aize is fixed and the spacing is altered. The strut length of a dome is measured from vertex to vertex so you will have to adjust the strut length to account for the difference in the hub diameter. The brackets create as many problems as they solve and given a dome built with them could be up to 5x -6x more expensive than an alternative hub method i wouldnt say they are necessarily a better dome hub.
Interesting. What size would be useful as a test? What material? I’m inclined to cast a few in aluminum or bronze just to see where the forces go.
Great thinking - only if using as a universal hub you need to be able to fix a screw in the center face of your strut. Now that is rather difficult when using metal conduit or other types of tubes. But you are the wood guy Paul - so that will be a good hub your green house uses. For larger Domes the hub should be looked at with regards to shear forces under different loads - it looks not too strong in my humble opinion, unless you cast it from steel or do a CNC milling job.
So compared to the Ring and punched sheet metal (at 1:26) that you didn't like in your video it seems rather more costly to make a strong version of your more complex design that that ring hub.
Also - Have you looked at the simple angle iron idea? Seems similar with the screw in the center face of your strut, but is by far less complex. There are guys selling it made from plastic for small domes. But when using a thicker metal - all you need is to drill and bend it. I guess you have looked at this as well. Let us know what you think about that design. Let's stay creative, constructive and connected - many thanks to you for your great passionate work.
I love the direction this project is going. I like that (presumably) it can be preattached to each end of a strut before constructing a dome.
Some thoughts...
I tried to visualise it but it's not clear to me this gives the freedom of movement needed. Can it all be angled for each strut while still allowing the holes (for the bolts) to sit flush with each other?
The gap in the middle of the hub will vary. Could this add extra complexity in other areas like the parts used to cover the dome?
Even for a 3-way hub I count 15 individual parts to deal with. Possible to reduce further?
Could the bolts work lose over time? Eg if lots of little vibrations from wind over time.
I'll do a more detailed video showing exactly how it works, it is a little hard to visualise because it's very different from anything else. Yes the gap will vary, this means that some struts need to be a little shorter, I'll do strength tests on all hub configurations when I have prototypes. There are two unique components, all the nuts and bolts are of the shelf so I don't count them. Yes there will be a lot of parts (several hundred in a 3v - 4v dome) this is why the cost needs to be as low as possible. Not too worried about bolts working loose as lock nuts can be employed. Oh and for your first question, yes you would fit the hub to the strut first.
Love the idea and concept but one flaw is the fact it’s set on a flat plane the domes angle in depending on the frequency at the joints so like a 5 frequency dome 20 foot diameter has a 6 degree angle need to make the hub pivot at bolt connections or make preset angles for each design angle but the overall design is great and would love to see this as a viable solution for connections in domes
The Guillory's Louisiana Homestead The two "ears" are not coplanar. Because these "ears" are attached to independent "hubs" or "collars", these "collars" can rotate about the same axis to create non-coplanar angles... See 6:10
I like it, when will it be on Kickstarter? What would the possible load be? Thinking about kids climbing...
Could you beat/stamp/drill out two "wingnuts" as in your design from metal pipe or softened PVC ? pros: no parts at all, cons:wouldn't work for wood struts, also you'd need different stamping angles for 5-way and 6-way (then again that only means having 2 different variations if you're building domes). The device design for the stamping/pounding guides would take you a couple of minutes. The only manufactured components any builder needs are the 2 jigs, reducing supplychain exponentially. Just a thought.
A very nice design hub, but the screw at the top of the strut in wood is critical if it is used in some sorts of wood which are not durable.
At 9:20 you describe using pipes, but I don’t understand what you would be screwing the flanges into if the pipe is hollow. I’m building a 5/9 3V dome out of aluminum and am struggling to find a suitable hub solution for the reclaimed 26.5mm tubes. 3D printing seems like best bet at this point
Is the cone shape really necessary? I can envision a simple cut rectangular piece of steel with the "ear" at the end angles so that the the bolt hole is centred along the top longer edge, matching your models position. It could be laser cut, or even a jig saw for proto-typing. Then roll the long rectangle ensuring the "ear" is at a right angle. I'm picturing a door hinge, how the tubes created by the by rolling the metal are stacked with the pin going through them. You could probably cut a door hinge to just to try it out. Just a thought.
at 9:04 you're saying you can have any angle (which will be needed in some cases, like a 6-way hub with 2x55.7 & 4x62.2 degree angles), but I didn't get it how you achieve that?
Otherwise looks great!
you could make a small 3d printed model prototype! if you could put the files (preferably step files) on thingiverse so i could print these to test them that would be great.
That's a great idea, I'll get the files made shortly.
It looks like the same principle as the wanger flange from the uk
Is the same part used in all the N-way connections and dome frequency configurations?
I like the design. One question: How do you adjust for the dihedral angle?
That's why there're two joints per pipe, when the screw in the axis of the pipe is loosened you can rotate them freely to the desired angle and then tighten it. I assume they'll all be slightly loose while you're assembling at least one row of the structure, and then when it's complete and the angles set by the whole structure (because of the struts lengths) you can tighten them.
But I didn't get how one would get the different angles between the struts. There are some irregular joints like the 2x55.7 & 4x62.2 degree angled hubs in v3 dome
I think hub caps could be cool
Is the angle of the cone 6.5 deg. Like with the G15 greenhouse plans that I purchased?
No this is a different build system altogether, the GD15 uses a beveled frame, the 6.5° bevel only works on a 3v dome. this system is designed to work for any frequency, I don't think this system is as good for polythene greenhouses but it would work great for tents, climbing frames, educational projects etc
I like it for its simplicity, however I think it has a fundamental limitation to scale. the connections can only be so big and I think it limits the strength to weight ratio so your not going to be using it to build any geodesic super domes. I am envious of your sketchup skills, I too have a hub design in my mind but lack the sketchup skills to make the model. My design is more robust hub that has some added features as it can be incorporated into a double geodesic dome for a super structure that could be used in concrete forming or aircrete forming.
What about hub cover to allow roofing materials such as 5/8 or 3/4 plywood
I saw a hub that was cut from plywood and the struts were slotted at the appropriate angle and then a wooden dowel was used to pin it together at each strut. Very large livable dome. Used 2x6 for the struts and the hubs appeared to be 3/4” plywood. A CNC router could make mince meat out of it all I would guess. Anyway, anyones thoughts are info about this sort of dome build system?
Did you made them finally / update / improvement?
Put groove on inner part of hub ears that you bolt so they lock into each other after positioning them .Also those ear taps that you bolt would have to be thick for strength. COULD BE A WEAK POINT
Can you confirm that you remove the diameter (2 x radius) of the hub from the length of strut given by the calculator?
Design suggestion.
Piece #1 ( top cone )
Piece #2 ( bottom cone ) create a spline(tenon) that comes off of the Bottom surface. ( think mortise and tenon attachment to the strut material)
end material can be easily mortised ( jig saw, hand saw, table saw ) to receive the tenon.
any material you choose to make the cones out of can be cross drilled while in the endgrain of the strut.
strut owner can countersink any hardware used to attach strut to Hubcone #2
thickening the "hole" attach point to the cone...( twist minimalization ) 4:29 of the video. Where the "arm" meets the cone.maybe a triangle instead of a rectangle?(topview)
also... CZcams videos do not protect your "patent" idea.... take your design, print it, MAIL IT to yourself... while you wait on the patent to process... this is a definitive DATE Stamp that will hold up in any court.
As soon as a design is published it becomes unpatentable. Even if he'd remove this vid now, he'd be unable to patent it. He has now created his "prior art". Prior to filing, the idea should be kept an absolute secret and certainly be disclosed nowhere in public.
how do you attach poly carbonate or ply wood to the pipe. in the US it needs to connect a 2x4 foe a green house for building codes.
You can use any shape timber you like, these would work just as well with 2x4 timber, I'll put something together in sketchup
Thank you I bought your plans and can not start the project til spring.any other ideas to make things easier will be fantastic.
So the "hub" doesn't angle and the struts need to be cut with the correct angle at the end?
No struts are cut at right angles, the hub does all the angle work, did you see how I rotated the top lug at 6:10 this makes the correct dihedral angle automatically.
will it have a limited angle movement? will it strong enough to prevent the structure being collapse?
I would agree with Mårten Woxberg. 'So the "hub" doesn't angle and the struts need to be cut with the correct angle at the end?'
That's how I read it. The lengths of the struts set the angles, the hubs conform to the struts. It does mean the struts have to be fairly accurate but that's easy to do.
Hi Paul,
I've designed new (I hope better & simpler) geo-dome hub connector. One that should be universal for all the angles, and also that can be made only by the most standard & commonly available steel profiles (or other materials if strong enough for the size & purpose). I made a small SketchUp project to illustrate.
3dwarehouse.sketchup.com/model/c63c616b-60b5-497a-a88a-c1cff30269f0/Universal-Geodesic-Dome-Connector
There's detailed description in the project too. But here's the main idea:
Around the hub of course we have either 5 or 6 struts (I prefer to use rectangular tubes since when tightened they'll fit to the other flat elements' surfaces and add some friction force. But there's no big issue to use round tubes for example, perhaps with some spacers);
In the middle there's the main hub, which is basically two flat plates (steel in my case).
These plates should have either 6 holes or 5 holes at needed angles - I mean general angles like the 5-way hub should have it's holes at about 72 degrees, and 6-way hub at about 60 degrees. For a v3 hub actually most of the 6-way hubs will have angles like 55.7 & 62.2 but they're close enough to 60 and the rotation that the bolts give will allow adjustment to the exact needed angle (automatically by connecting the struts with correct lengths). So no need to be super precise and drill different plates with tiny angles differences.
The plates should also have some corners cut so that after the hole there's the same distance to the end of the plate - in my example I'm using M14 bolts, and leaving another 14mm of material on the plate, then cut perpendicular to the line between the plate's center and the respective hole - should be simple enough.
Then there's the 'magic' :) short square profile pegs (in my sizing 30x30x90mm). They're also very common profile, just square extrusion profiles, pick the needed width cut in pieces (90mm in my case) and then drill two holes for the M14 bolts, but drill them on perpendicular sides of the peg - ie you should get something like a middle of a Cardan-Joint (or CV-Joint) one of the holes will go in between the hub plates, and the other in the end of the struts' tube.
So the bolts on the plate will allow to adjust the exact angles between the struts, and the other bolt (thru each struts' end) will adjust the dihedral angles between the dome panels.
This design isn't something original - actually functionally it's very similar to the one you show at 1:24, but without such custom parts or assembly.
The main advantage is the simplicity - no custom parts of processing is needed - just simple cutting at certain lengths and drilling some holes.
Optional) For smaller and lighter domes with lighter frames, the two plates (if thinner sheets are used) can be reinforced by adding a ring with the same thickness as the square-pegs - very much as the ring-hub design from ZipTieDomes . This should reinforce the plates against bending caused by high load and the fact that load direction is not in the same plane (ie at about 156 degrees instead of 180). The distance between the inner ends of the square pegs should determine the ring diameter. These rings can also be cut from standard (wide) pipes, nothing complex.
If the struts have thinner walls laying all the weight on single bolt might try to bend the connection point of the struts (the bolts if chosen correctly can take much higher shear forces) but the ends of the struts can be reinforced by short sleeve, ideally same shape profile, just a size larger so that it can wrap around the strut end. Then more bolts can be used between the strut & the sleeve if necessary, and the single rotation-bolt would got thru the thicker total walls of the strut & sleeve - this should solve potential bending at the struts' ends without the need to use larger & thicker struts for the whole length, but just the ends.
What do you think? I'll appreciate your opinion!
I suggest that you try to condense this concept into a 30 second video and submit it to AvE. He is offering to mill prototypes on his new 5-axis Haas machine if people have good ideas to work with. Check out his channel, just type 'ave cnc' in the search bar.
Thanks for that, I've subbed to Ave's channel but not seen this yet. Great idea, I'll do it now.
I saw the clip you uploaded. I'll post a link to it on AvEs channel. It'd be great if this works out.
Any updates on this project ? Did you get your prototypes ?
Please do another video when the product actually exists.
The product has been live now for maybe a year, you can get more info here: wangerflange.com/default.html
@@Geo-Dome , thanks for the reply, looking good!
you still into doing this? because I'm setting up a personal foundry over the winter
Surely all the struts have to lie in a plane?
The lug with the hole and bolt lie on the same plane as each face, it's the rotating lug at 6:10 that makes this possible.
Ah - I see now that the cone is in two pieces. Serves me right for watching it on my phone!
Paul Robinson Thank you for sharing this brilliant design. I have some questions... After reading through the comments and digesting all the "coplanar" comments, I can understand the confusion. The various hub configurations at 7:50 look somewhat coplanar, but I can imagine these flexing to create dihedral angles. I can visualize the center "void" of the hub increasing/decreasing in size and the "ears" rotating axially to each other. Wouldn't these need some sort of keying/knurling/toothing to prevent undesired axial rotation of the "ears" once the proper angle has been acheived depending on dome frequency or hub angles. Any external loading may deform the dome. Depending on the friction of nut and bolt fasteners may be insufficient to prevent warping of the hub angles.
Useful Invention? | Geodesic Dome Joinery . Saw this and thought of you. google it almost the same idea.
I work in company who is in steel industry. We can cut and bend. Can you send me a model please.
hi paul, i was thinking over your design. i don't know how to attach here sketchup file or images. as others noted below i kept in mind strength and locking ability. so my version is made of steel flat bar. (dome struts are straight steel pipes right angle cut).the flat bar bent around the strut - one end is a small "ear" while the other end is the long "ear". long ear to connect struts. between small and long ear tighten the screws to make fast the set position on strut.
plus.google.com/u/0/collection/sxPkPF
is my g+ account
hey Paul, if you're still out there I would love to talk with you and maybe even pay you for your time. if you're interested please reach out. thanks!
Don't use one. Cut the struts at the right angle in the first place. No need for added cost.
Oh no.%io
Are you still working on this, pm me on Facebook Erwin Vanmassenhove... Or linkedIn.
Yes, I have a website and sell the brackets now. www.wangerflange.com
not cheap not realistic everything started with a greenhouse dome so that means everything must click together with 3 sec a triangle or its not easy not fast and not cheap!!!
Wouldn't work