pic: 2791 Concept Arm Frame

[Sh1ine]

loading photo ...

[Chris is me]

Probably should have sent this as an email, whoops.

Right now there's no room on the arm pivot for a sprocket or anything behind the pivot point. I'm not sure how to fix this but it looks like as long as the long 2x1 pieces are mounted on the back like that it'll be a problem.

[MrForbes]

see if you can get the arm to weigh 10 pounds or less...5 would be about right

then yeah, it's overkill....

[Chris is me]

Originally Posted by squirrel

see if you can get the arm to weigh 10 pounds or less...5 would be about right

Should be about right with 1.5" PVC and a roller claw.

[MrForbes]

They make 1.5" ABS sewer pipe too, it's lighter and tougher than PVC, and looks so cool since it's black. We're currently planning our arm to be made of 1.5" ABS at the manipulator end, and 2" ABS at the arm pivot end...it'll do an "extendo" maneuver at the beginning of the match to become a longer arm. If it all works, that is. The prototype is assembled, but not yet powered or mounted to a robot.

[gvarndell]

That's gonna make one heck of an obstacle when it's lying on its side in the middle of the field.

[Chris is me]

Originally Posted by gvarndell

That's gonna make one heck of an obstacle when it's lying on its side in the middle of the field.

Not if it self rights?

[scottydoh]

Be careful of rule <R45>, It appears that you have three CIM motors on each of those drive gearboxes.

<R45> Motors specifically permitted on 2011 FRC ROBOTS include:
C. one or two additional 2½” CIM motors (part #FR801-001 and/or M4-R0062-12) in addition to those provided in the KOP. This means that up to four, and no more, 2½” CIM motors can be used on the ROBOT,

[Chris is me]

Originally Posted by scottydoh

Be careful of rule <R45>, It appears that you have three CIM motors on each of those drive gearboxes.

We have 3 CIMs in the model, but we did that just because there wasn't a BB + CIMple Box model available while designing.

[scottydoh]

Originally Posted by Chris is me

We have 3 CIMs in the model, but we did that just because there wasn't a BB + CIMple Box model available while designing.

Gotcha, Just wanted to make sure.

[Joe Ross]

Originally Posted by Sh1ine

Please forgive the poor Photoshop Job. I am looking for a bit of advice. Although we have not nailed our arm manipulator design yet we want to be able to get the fixed upright welded when the rest of the frame is in the shop. Currently I have it drawn with 1/16" wall tube. The two vertical pieces are 2x1 the rest are 1x1. Do you think that this system will be strong enough to support a arm that can reach to the top peg and weights around 30 or less lbs? Is it overkill? Thanks.

On 330, we put our mast back a few inches to allow room for a big sprocket at the top. http://www.chiefdelphi.com/media/photos/27675. We use 2x1 1/8" for the mast, which is probably overkill.