Concept Design for UL Cuben fiber, Silnylon, Carbon fiber, Dyneema cord, fully collaspseable Umbrella

You could put a threaded insert into the two battens and then add a threaded end to the handle.

http://www.grainger.com/category/thread-insert/fasteners/ecatalog/N-8nr

Thanks James, yes that's kind of what i'm looking for. I'm just wondering if putting it through the carbon fiber strips will weaken them too much or not.

They are used very commonly in Aerospace applications in carbon fiber. You may have to do some sort of reinforcement lug around the area to thicken the batten up enough to accept the insert.

If you come up with a triangular version of the umbrella that could block off the open end of a tarp – I'm all in!

Hi James,

I really appreciate your help. Triangular sounds interesting… Stealth bomber umbrella?

Triangular would be a good design for shade, to maximize weight to surface area efficiency, especially when the Sun changes angles during the day, but i suspect that circular tends to be better for rain protection.

In some ways, triangular would be easier to make. Well, in any case, i've already started to work on a prototype, and guess what, it's triangular. Dimensions: It's 48 inches wide at the base, 36 inches tall to the apex–these are practical–it's easy to source 48 inch carbon fiber strips and material/fabric comes in lengths of 36 inches. It will have 3 rectangular strips of carbon fiber. One 48 inch strip for the length of the base, one 36 inch strip going from the base to the apex, and one strip about half way between the base and apex, horizontal to the base strip–this last strip will be about 24 inches (another easy to source length for carbon fiber strips).

These will all go in silnylon sleeves that will be sewn shut on one end, and have a velcro flap on the other to make it easy to put them in and take them out.

I'm still trying to figure out which exact insert i should use. I just sawed a golf shaft at the point where the golf head (?) is connected to the carbon fiber rod. However, the ID of the shaft being 1/8th in/.125, seems to small for many of those inserts. I may have to cut down further to get a wider ID.

I'm so far leaning to using a well nut inserted into the carbon fiber pole, which i plan to epoxy in, then using a matching thread insert (both of these are found under "Nut Inserts") to put through the two strips, and then a longish, flat head screw to go into it all. Not sure if that will work, as i've never worked with these things before (or much hardware in general).

Anyways, tell ya what, if this prototype works out well, in appreciation of your help so far i would charge only approx. materials price for it, if you wanted to buy it. I guesstimate it will weigh between 2.5 and 4 oz total and materials price to be somewhere between 50 and 70 dollars.

I'm definitely in. Good luck on the project. Let us know how it's coming along.

How do you keep the edges stiff? Without some kind of reinforcement they will collapse leaving just a square. Since you're using CF, you can tie cord between the tips to curve the shape, like two interlocking bows.

Seems like it'd be a nice, fun little project to mess with though!

Hi Dustin,

Thank you for the feedback. I could see that as possibly being somewhat an issue with the circular design, but i was hoping that 6 "ribs" rectangular strips of carbon fiber, combined with a somewhat stiff material (reflective cuben), might be enough to keep most of the shape. I wouldn't actually want it super taut around the edges–that's one of the problems with current umbrella designs in some ways, being so concave and having the material tight on the edges turns the umbrella into a type of all around wind sail. However, with the traditional rib system of an umbrella, you need all the material to be taut.

This design would need to very slightly concave as to not pool water though.

In any case, i've switched up designs a bit, and currently am making a triangular shaped one, which will have more of a full edge frame. I liked James idea of double duty as shaped tarp door. Hopefully it will have enough surface area for rain though!

If you want it to shed water you don't want it flat; it must be a dome, however shallow a dome you prefer. To make a dome you cut "gores" of fabric; how many is dependent on how many ribs you plan to use. You can find calculators online that will give you numbers for a hemispherical dome, and then by eliminating most of the hemishpere you can come up with a very shallow dome. Or of course you could wing it just by introducing a gentle convex curve into the edges of four triangles and sewing them together (assuming four ribs) – should be close enough to work and you can tune it up as you go.

Hi Paul,

Yah, i know about the water thing. The original idea with the circular design was to have the fabric/fabric sleeves a bit shorter than the carbon fiber strips, putting some tension on said fabric bowing it a bit.

In any case, right now i'm working on a triangular design. The carbon fiber piece going from the middle of the base to the apex, will also be a bit longer than the cuben material, and same with the cross piece. Just enough tension to bow the fabric a bit, so that water doesn't pool as would happen on a completely flat surface.

Worked on the umbrella quite a bit yesterday. Mostly finished. Some issues though. I've never worked with solid, carbon fiber strips before, so when i ordered some online, i wasn't exactly sure which thicknesses and widths would be most ideal.

Turns out that the 3 outer structure strips, think 3 strips that make a triangle, are too thin, without enough stiffness, so it doesn't tension the fabric quite enough.

Turns out the piece i used for the middle going horizontally across the triangle was too thick, and when i was bending it into the end/securing pouches, it snapped in half at the drill hole area.

The carbon fiber strip i used for the middle going vertically up/down the triangle, seems to be just about right thickness, but i've decided that i'm going to reinforce the middle area at the drill hole site with some "FiberFix", just to be on the safe side.

Fixes i'm thinking of for the other issues. For the 3 outer structure "ribs" aka carbon fiber strips, i'm thinking of replacing with 3 thin bamboo rods. Inexpensive, good weight to stiffness, flexibility, and strength ratio and might fit in the pouches i already sewed on.

For the middle, horizontal piece that needs to be flat, and will have a hole through the middle, i'm not sure what to do. I'm thinking of taking the 3 other carbon fiber strips, laminating them with epoxy and/or wrapping at the middle and ends with the "FiberFix". However, these strips are still too narrow to drill a hole through… So, don't know what to do there. Have thought about taking a couple of small, thinnish squares/rectangular pieces of wood, filing out enough material for the 3, thin carbon fiber strips to place in between, gluing the two pieces of wood together, then drilling a hole through.

Since this is just a prototype, i really don't want to have to order more carbon fiber strips, especially since the company i originally ordered from has a 30 dollar minimum order with semi expensive shipping.

If i go the wood reinforcing route, what would be the best kind of wood to use for the small squares or rectangles? Something with a little flexibility would be good.

I will try to put up pics tomorrow of the project so far. Looks and feels like a kite. Will have two oval slits with overlapping flap, in order to not catch wind like kite. The actual fabric part of the umbrella so far is really light, .7 oz. Course, carbon fiber strips, handle, etc will add all the significant weight.

I haven't yet put in the venting slits/overlapping material. Still haven't replaced the horizontal cross piece, or replaced the outer structure with bamboo. Need to do some research into different woods… (hint, hint).

But here is a pic of it so far (i realize it's not perfectly symmetrical).

Btw, the pouches for the structure strips/rods, are made out of a combo of 1 oz cuben and silnylon. The silnylon went on the inside for abrasion resistance and the cuben on the outside for tensile strength. Later on, they will be taped on the outside with cuben tape to prevent water ingress through the threads.

In the middle of the umbrella, will be a few strips or so of cuben connected to velcro in a circular pattern. This will be too further connect/anchor the fabric/umbrella part to the carbon fiber pole, along with the screw that will go through the two intersecting middle strips and into the carbon fiber pole.

…could you just add three more struts to form a triangular pyramid. Then you can hold on the apex or the end of either of the three, in use. Would be very strong. I like the triangle idea :-)

Thanks Adam. Not sure if my brain is working all that well right now, because I'm not sure what you mean. Do you mean a few horizontal cross strips/ribs? Or something else?

Sorry about slow response.

At the moment, it looks like you've made a triangle. Now, with three more struts of the same length, add them to turn the frame into a triangular based pyramid. Flip it upside down. You can now hold it by either strut or grip it at the apex. Saves you holding your arm up at full length.

This project got way laid by lack of funds and the unforeseen breaking of one of the carbon rods.

In the nearish future i will be able to afford working on it again.