Cool Frame Ideas?

[M. Mellott]

Here's a product I found...I haven't invested any funds to buy pieces for testing, but it looks great for making quick prototype frames:

http://www.eztube.com/

[Qbranch]

Originally Posted by M. Mellott

Here's a product I found...I haven't invested any funds to buy pieces for testing, but it looks great for making quick prototype frames: http://www.eztube.com/

Watch out!

We tried this stuff and it does look fantastic on paper, but they have a huge issue with being out of square. Well, not the connectors themselves, but what you put together with them. When we tapped our connectors in everything was nice and strong... but horribly out of square.

The robot frame we put together couldn't even hold an axle straight, let alone sit level. Maybe if you used force gauges or something when pressing the connectors in, or had really close tolerancs on the ID of the tube you use it would work... but just a heads up, with your ajax square tube it doesn't look too pretty...

-q

[wilmo]

Watch out!

We tried this stuff and it does look fantastic on paper, but they have a huge issue with being out of square. Well, not the connectors themselves, but what you put together with them. When we tapped our connectors in everything was nice and strong... but horribly out of square.

The robot frame we put together couldn't even hold an axle straight, let alone sit level. Maybe if you used force gauges or something when pressing the connectors in, or had really close tolerancs on the ID of the tube you use it would work... but just a heads up, with your ajax square tube it doesn't look too pretty...

The EZ Tube was exactally what I was looking for someone to say. Did you use your own extrusions or the Eztube extrusions made for the connetors, did you use the composite or the steel core?

[JamesBrown]

Last year with 1493 we built a custom frame, the sides contained the transmission (a custom 2 speed based off the AndyMark shifter) and the wheels, the two sides were connected by 1 inch square tubing with 1 inch solid aluminum cubes welded on the ends. We threaded the cubes and connected the sides with counter sunk bolts. this allowed us to quickly remove one entire drive module and replace it with a spare. Allowing us to make repairs without having to miss matches of work directly around the robot.

I am going to attach a picture of the chassis, if you have any questions feel free to ask.

[AdamHeard]

Originally Posted by JamesBrown

Last year with 1493 we built a custom frame, the sides contained the transmission (a custom 2 speed based off the AndyMark shifter) and the wheels, the two sides were connected by 1 inch square tubing with 1 inch solid aluminum cubes welded on the ends. We threaded the cubes and connected the sides with counter sunk bolts. this allowed us to quickly remove one entire drive module and replace it with a spare. Allowing us to make repairs without having to miss matches of work directly around the robot.

I am going to attach a picture of the chassis, if you have any questions feel free to ask.

Just curious.... Why were the center wheels located more towards the centerline of the robot than the outer wheels?

[JamesBrown]

Originally Posted by AdamHeard

Just curious.... Why were the center wheels located more towards the centerline of the robot than the outer wheels?

If I Recall it was just an ease of mounting decision. We wanted wide wheels in the center to push but didn't want to have to make the whole drive module wider.

[M. Mellott]

Originally Posted by Qbranch

Watch out!

We tried this stuff and it does look fantastic on paper, but they have a huge issue with being out of square. Well, not the connectors themselves, but what you put together with them. When we tapped our connectors in everything was nice and strong... but horribly out of square.

The robot frame we put together couldn't even hold an axle straight, let alone sit level. Maybe if you used force gauges or something when pressing the connectors in, or had really close tolerancs on the ID of the tube you use it would work... but just a heads up, with your ajax square tube it doesn't look too pretty...
-q

Thank you for the info--I too was hoping that by mentioning EZ Tube, somebody had to have seen it and tried it. Yes, I would imagine that in order to get a box frame that was square, you would have to have the opposite tubing pieces cut with 90 degree squared ends and be very accurate on the lengths since the lengths are controlled by the connectors bottoming out against the ends of the tubing. Keeping it squared up could probably be helped with some thin aluminum gusset strips and rivets, but now it's not so EZ.

Now that I've had time to look, the 80/20 system and the EZ Tube system look very similar, at least in concept, even with the availability of extruded tubing with panel-mounting flanges. EZ Tube connectors seem longer and have the option of the steel-core reinforcement (probably adds too much weight for a robot frame...probably).

Of course, if you're not worried about reusing the connectors, you could always use standard thin-wall 1" tubing and some two-part epoxy like JB Weld.