JVN Build Tip: Mechanism Loading

[spacepenguine]

Wow. Thanks John! That's just the solution I needed to counterbalance the arm without blowing the 120lb limit or introducing the complexities of a ratcheting system. That's just too simple.

[Gary Dillard]

We planned to use the FP motor with it's gearbox and a rack-and-pinion for our vertical lift, and knowing how the FP's do not like to stall (I think they were the original source of "magic smoke" back in the days before CIM's when they were one of the choices for drive train motors) we decided to use constant tension springs available in a wide range from McMaster. We assembled everything that was going to be lifted, weighed it, divided by 2 and ordered 2 springs in that range. No close fits required - the ID of the spring is over an inch so we just stuck a 3/8" bolt through it, attached it to structure and screwed the other end to the arm. Works great - without the motor even installed you can move the arm to any position and it stays there.

[Aren_Hill]

We cheated to learn this by just copying 148's arm in 2007, works quite well

[Chris Fultz]

Originally Posted by Aren_Hill

We cheated to learn this by just copying 148's arm in 2007, works quite well

So did we. Can we claim collaboration?

[Aren_Hill]

Originally Posted by Chris Fultz

So did we. Can we claim collaboration?

Well we did it in 07 during the fix it windows, this years pretty different on our end.

So if collaboration can be applied over long time periods maybe