Can someone tell me the type of spring mechanism used by some teams in 2010 to climb with out using an electric motor? In the videos some of the robots continue to climb after match play is completed.
The name of the part and possible suppliers would be appreciated. Any idea on their weight? How did you “wind” the spring before each match?
Thanks.
Some used surgical tubing. Some used constant-force springs (McMaster.com). (We used neither, so I can’t speak to how others attached their mechanisms).
The constant force spring listed didn’t seem strong enough to lift a 2010 robot. Is there another type of spring that could have been used?
There are other places besides McMaster that sell constant-force springs in larger load capacities. Lee Spring is one source.
If you choose to go a stored-energy route, be VERY CAREFUL, especially with constant force springs. They are sharp and can easily snap back and cut off a finger, poke out an eye or worse. Gas shocks can be safer a lot of the time if they have damping to limit their speed. Regardless of the method, any stored energy solution with enough force to lift a robot off the floor will be dangerous, just due to the energy and forces involved.
And be ready to explain to inspectors what you have done to keep your system safe… on the field and off. As an inspector I’m going to be getting hands on with lots of robots and I really like getting all my fingers back, intact. It makes it easier to sign off the form as “complete”.
Not that stored energy systems can’t be done safely… of course they can… I know there were some threads on CD back in 2008 about it when we were throwing those big exercise balls around the track… but having clear warning markings, guards, and physical lock-outs are a good start.
Jason
Thanks for the heads up on passing inspection and avoiding injuries. That would be a lot of stored energy to lift a robot.
Look at RUSH Team 27 robot for 2010. Don’t have a picture though…
Link is right here: http://www.chiefdelphi.com/media/photos/35095
1717 had a nice gas shock lifter in 2010.
http://www.chiefdelphi.com/forums/showthread.php?t=63289
http://www.chiefdelphi.com/forums/showthread.php?t=65392
http://www.thebluealliance.com/match/2008new_qm75
(See ~58 seconds for us throwing, watch how we back up to throw 
)
Anyhow, we used a garage door spring that took more than 200 lbs of force to winch down. Our winch mechanism was machined from a solid block of aluminum, everything in contact with the spring was robust.
In the center of the spring was a metal wire, if the spring broke parts bigger than a loop would stay on the wire. Encasing the spring was the “Super Bimba Ultra”, which prevented anyone from touching the spring and getting pinched, and also prevented parts from spraying.
When ending the match, we ALWAYS attached tie down straps from the arm to the frame, so that if the release mechanism failed during transport, the arm didn’t swing violently.
When we got back to the pits, we always had about 4 sets of hands on the arm to gently release the spring, but NEVER on the short side, ALWAYS with leverage.
If I remember correctly I think HOT’s 2010 robot used them as well. That robot could hang in a heartbeat as shown here.
If you are looking to continue to climb after the buzzer, a single solenoid valve will always default to a known state when not energized. This can be useful since it will trigger automatically when the robot is disabled, but that can be a bad thing too.
I think you’re thinking of 67’s 2010 robot.
As I understand it, they used 4 (or so) gas struts that were cranked back before each match.