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Hastypickle
01-26-2009, 09:34 PM
Is there some sort of electronic quick release mechanism that we can use on a motor being used as a winch? I think I remember there being a mechanical one a couple years ago, but we got rid of it last year.

DonRotolo
01-26-2009, 09:36 PM
3 years ago we used a small pneumatic piston to pull a "grenade pin" from a mechanism at the start of the match; it was there for safety and we didn't want it released until nobody was near-by.

Kevin Sevcik
01-26-2009, 09:39 PM
Any electronic mechanism is going to be illegal as an electronic solenoid or extra motor or something. So you'll need to go with some kind of mechanical quick-release. There's a rather lot of options, but it depends on how much load you're releasing and how you're winding up the load in the first place.

Hastypickle
01-26-2009, 09:40 PM
We want to be able to set and release it multiple times throughout the match as we are using it for our ball scoring device.

Edit: We are using a fisher price motor to wind up the load. I'd estimate that it is about 15-25 lbs of force.

Gdeaver
01-26-2009, 09:52 PM
You do have the hitec servos and FTC servos available. Could be used as an actuator for a drum brake. Multiple servos could be ganged together if the force of one is not enough.

Kevin Sevcik
01-26-2009, 09:55 PM
I actually happened upon a ridiculously effective quick release based around an FP, a low ratio BaneBot planetary transmission, and a worm-wormgear set. With a servo with a cam to shift things. I can sketch something up in Inventor if you want to see how it'd work.

Hastypickle
01-26-2009, 09:57 PM
I actually happened upon a ridiculously effective quick release based around an FP, a low ratio BaneBot planetary transmission, and a worm-wormgear set. With a servo with a cam to shift things. I can sketch something up in Inventor if you want to see how it'd work.
Sure.
I was thinking maybe the pneumatic actuator could be used, but I don't know how much force that would be able to hold.

EricH
01-26-2009, 10:52 PM
Sure.
I was thinking maybe the pneumatic actuator could be used, but I don't know how much force that would be able to hold.
If you design it right, it can hold a lot. I know that 330 fired a short-throw cylinder into a winch powered by 2 FPs back in 2004 to keep us on the bar. We never had a problem with it.

KE5WGE
01-26-2009, 11:08 PM
1391 used a 1 inch pneumatic piston to hold back our launcher in overdrive. I think we had about 300lbs force held back by a simple lever actuated by the one inch piston.

Depending on the device you are trying to hold back, there are so many ways to do it with pre-made devices but I would recommend just throwing something together that does the job and that is simple and easy to make another one of at a competition.

Chris Fultz
01-26-2009, 11:15 PM
Sure.
I was thinking maybe the pneumatic actuator could be used, but I don't know how much force that would be able to hold.

at 60 psi, a 3/4" diameter cylinder has 26.5 pounds of force in the extend direction and 23.5 in the retract direction. If that is not enough, you can step up to a larger diameter.

the equation is f=pa, or force = pressure x area.
for the example above, in the extend direction it is

f = 60 pounds / inch^2 x 3.14 (.375^2) = 26.49 pounds

for the retract, you have to subtract the area of the internal rod,
so the effective area is reduced (0.25 diameter = .125 radius)

f = 60 pounds / inch^2 x (3.14 (.375^2) - 3.14 (.125^2)) = 23.55 pounds.

CraigHickman
01-26-2009, 11:25 PM
Mod an Andymark Gen1 shifter, it has the release ability you're looking for as well as the ability to "wind up" whatever you're looking to build, if you do your design work right.

qwertyuiop[]\
01-27-2009, 08:55 AM
you could just have a piston push all of the rope off of the open end of the reel.

Dad1279
01-27-2009, 11:03 AM
Fishing reel? Motor to wind, servo to release.

Aren_Hill
01-27-2009, 11:12 AM
http://www.chiefdelphi.com/media/photos/31538

http://www.chiefdelphi.com/media/photos/31539

you dont need pneumatics for quick releases....;)

Chief Pride
01-27-2009, 12:32 PM
You could take a pipe, cut it in half and put it on a shaft, make a notch in one and and a reciprocating notch on the other, mount fasten the left side of the cut pipe to the shaft, use a pnuematic shaft to push the two pipes together while winding, then use the piston in the other direction to dislodge the pipe... If that makes sense.



Edit: 400th post.

Kevin Sevcik
01-27-2009, 01:05 PM
Fishing reel? Motor to wind, servo to release.Fishing reel releases tend to lock when under load. Some of them lock very effectively even under a light load. AndyMark Shifters and other dog or meshing shifters are going to exhibit some amount of locking under load as well, simply because more load means more friction on the meshing parts. They probably will still be shiftable, but it's never going to be as easy as when they're unloaded.

Team 135
01-27-2009, 01:43 PM
I would use a small pneumatic actuator that came in the kit. We used this on a prototype to hot swap the trailer and it worked great even under tension.

bhsrobotics1671
01-13-2010, 06:47 PM
Could you PM me or provide me with more information as to how this winch system worked? We are very interested in this type of design. Thanks!

Pneumaticsman
01-13-2010, 07:11 PM
We are thinking of using a winch as well. We are thinking of having a winch to pull some cable back, which loads tension on some surgical tubing. Once tensioned, we plan on releasing a "clutch" that will disengage the winch and release the tension in the surgical tubing, thus kicking the ball.