Frame connections

[manleycor]

I am exploring a rapid framing system for prototyping. I know about the Bosch system what else is available.
If this subject was discussed previously where is it posted?

[sanddrag]

There is also 80/20 which is pretty much the same thing as Bosch. There is also this thread

[Jake177]

When we prototype our end effector (i.e. ball sucker, bin grabber) we usually use PVC pipe.

[Elgin Clock]

LEGO's!!!

You can't go wrong with prototyping with lego's!!

[maclaren]

Our team has been working on a system for just that purpose and it just so happens that we have named it the rapid framing systems.

The concept:

The way it works is there is a cube in in the center on the corner. This cube has a thread thru hole on each of the six faces. There is another part of the system called a plug that is mounted to a face of the cube. This plug has a counter bored thru hole that is designed to be a clearence hole for a 1/4"-20 socket head cap screw. Towards the end of the plug there are four small threaded holes that are used to fix the tube to the plug that it slides over. Also the four small screws that go in those holes keep the socket head cap screws from backing out. On the faces of the cube there needs to be some sort of fixture on the faces of the cube that engages the plug to keep it aligned. This algining fixture can be accomplished in several ways. Slots, Pins and holes, or Sockets.


With this system it is extremely simple to produce a frame in less than an hour. Once you have finished a dozen of the cubes and plugs.

I will try to submit a few inventor snapshots to chiefdelphi sometime soon.

[Cory]

If I am understanding what you are describing, 80/20 already makes them, and Im sure Bosch does too.

[Edit] http://www.8020.net/pdf/Fractional/07%20Section%204%20(03-186).pdf Item number 4042 on page 112. Those things do get rather expensive as you start to use a lot of them, so I can see why you would want to make your own. We are thinking of spending a few days dedicated to nothing but fabricating connectors for 80/20 to cut down on costs.

Cory

[maclaren]

80/20 makes something that is somewhat similar.

However they differ in several important ways. First the 80/20 connectors are not reconfigurable. Our design is reconfigurable. The plug and the cube are two separate pieces. Second the 80/20 connectors are made of plastic. Ours are made of aluminum which is much stronger. Third 80/20 connectors use a special type of tubing which is more expensive and must be shipped to you from an 80/20 distributer. Our connectors use standard aluminum tubing which is cheap in comparison. Fourth 80/20 connectors are friction fit in place and require you to pound the frame together. Our connectors slide on and are screwed in place. Fifth since 80/20 is friction fit they can not be reused several times. Our connectors can be re used and reconfigured as many times as you want.

For those reasons our team chose to use our own design and not to use any premade connectors.

[Cory]

your point that you must buy 80/20's actual material is true, and making them yourself is no doubt cheaper, however, these cubes are made of aluminum, they are not friction-fit, and they are reusable. We used the cubes when constructing our cart frame last year. The cubes themselves arent tapped, but you tap the hole in the end of the 80/20 then you can bolt pieces together nice and square.

[Eric Bareiss]

I know that it is a bit much for some, but there is always Inventor. Building a virtual model is fast, pretty much free, and easily changed. It also gives you leg up on entering your inventor designs for Autodesk award.

Inventor is not as challanging as it seems, a novice can become proficient in a few weeks with the right training and motivation.

[maclaren]

I didn't realize exactly which 80/20 connector you were talking about. The 4042 isn't the connector that I had in mind. The connector that I had in mind was the 9200 series. The issue with the 4042 connector is that you can't make any other type of connector like a "T" connector with it. The connector that our team has designed is totally reconfigureable. You can make a "T" connector then use the same components reconfigue them and make a 3D corner connector.

[Sachiel7]

This year (in a few weeks) we're going to prototype our frame with wood extrusion. The aluminum version will probably need welding... We need to find somebody w/ an aluminum welder, and who knows how to use it!
We're using 1.5" aluminum square extrusion (hollow) for the bulk of our frame. We're taking our drive/chassis design from last year and improving it. We'll probably plan on using it if there isn't anything weird about the game that makes us change our minds.
Anyway, I'm actually making a frame that uses crossbars. My first time actually paying strict attention to structural integrity and force transfer. It's really not that hard once you get used to it.
We're also probably using 6601 sheet for our flatbeds.
I'm getting everything from onlinemetals.com, BTW. Just in case anyone's interested. You can estimate your cost and weight from their info.
Oh, and the frame I've got without any drive or electronic components should weight less than 18 lbs.

[NateBot16]

you could always try riviting instead of welding, not nearly as strong, but easy and effective.

[Tristan Lall]

Originally posted by Sachiel7
This year (in a few weeks) we're going to prototype our frame with wood extrusion.

Hmm...wood extrusion? You mean wood, plain, simple wood, right? Or something like particle board, maybe?

[Sachiel7]

Plain old wood. It's actually a 1" square extrusion (non hollow) bar.
As for the riveting, we thought of that, but we mainly need the welding for the crossbars, thus strength is the key. But a good suggestion, none the less.
One side looks kinda like this:

=====================
//\\//\\//\\//\\//\\//\\//\\//
=====================

Your typical crossbar pattern.
Since there's no 45 aluminum angle, you can't bolt it (easily), and it would take lost of bolts just for one side. I think we can dig up someone who can weld for us. My main concern is if a weld breaks at competition, then what? Hopefully another team would be willing to help...

[Cory]

All regional machine shops should have welding equipment I believe (?) I know that at SVR in 2002 we snapped a weld on one of our goal lifting arms and they were able to repair it. This may just be because we were at a college with a machine shop, but the capability should be there.

Cory