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Unread 28-01-2017, 23:08
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Kevin Sevcik Kevin Sevcik is offline
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Re: Legality of Linear Actuators

Quote:
Originally Posted by Retired Starman View Post
To cover yourselves, bring along the manufacturer's data sheet where it is called a SERVO and not a linear actuator. Get the version that has the same part number as the data sheet you have and be prepared to show an invoice with the price less than the limit given in this year's rules for a legal servo.

Do all this, and you should be good to go. I haven't used one of these yet, but I really like the concept.
This is, in fact, exactly what we did. Hard to argue with a manufacturer's website declaring it's a servo.

Quote:
Originally Posted by IndySam View Post
What gear did you use and how was you experience with these?
We actually used the L12-R, not the L16-R. It was to shove a piece of surgical tubing into a gear mesh to act as a brake on a lift, so it wasn't anything sensitive to force or speed. Just needed a small, easy to implement, non pneumatic linear actuation. Ours was a 30mm, 50:1 L12-R.

They worked fairly well, but it's definitely not a digital control in there. There's distinct overshoot past the eventual commanded position if you give it a step change. Even the 50:1 seemed slow-ish. Check the specs to make sure it's going to move fast enough for your needs.

I can tell you that while it's possible to unscrew the clevis from the end, you need to do it with the actuator extended, and rubber faced pliers on the rod to resist the torque. If you don't grab the rod, the servo internals aren't strong enough to resist the torque without damage.

I pulled ours apart to see what the students broke, but all I could tell is the wiper occasionally losing contact with the tracks of the linear pot it uses for feedback. So try not to repeat our mistake.
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