Hey everyone, new to the forums, and i hope this is the right section, my team is looking into using an electromagnetic gate latch to hold back a tension powered ram. We were wondering if it would be legal as long as we powered it from the distribution board.
We were thinking something like this product: http://www.usbuilderstore.com/securitron-1/gl1-gate-lock.html
not this exact model but the same idea.
What do you guys think?
thanks
Team 2002
The latch would be moving under the influence of the electromagnet, wouldn’t it?
The Q&A has dealt with several questions on electromagnets.
http://forums.usfirst.org/showthread.php?t=13979
http://forums.usfirst.org/showthread.php?t=14121 Note that this one outlaws any use of electromagnets to provide motion.
http://forums.usfirst.org/showthread.php?t=14093
Due to the second response linked (there are more than 3 out there, trust me), if you’re moving the ram with the electromagnet, you are in violation of the rules. By the looks of things, the latch is activated by the electromagnet, making it illegal per <R53> as interpreted by the Q&A.
Thanks for the quick response EricH,
However i dont understand what is illegal about this system. All it does is sit there and close on the incoming object then we supply it power and then releases said object when we are ready to fire…
Clarification please?
Thanks
The electro magnet cannot move something because it is providing motion. But I think you can use it to hold something with electromagnetic force and then release it when you want by turning off the magnet. That is legal because we did it in 2008 to great effect.
If the electromagnet in the lock moves something to release the latch it is illegal as an electromagnet providing motion has been ruled by the GDC to be a solenoid per the responses Eric linked.
If the electromagnet just holds the part in place, then releases it, with no motion of latch parts then you should be OK.
Thanks guys,
I think we will try the electromagnetic latch, but we’ll build a backup system in case we get to regionals and FIRST says we cant.
Thanks Again,
Hans
This “electromagnetic latch” is a solenoid actuator, which is expressly prohibited. There is no doubt it will be disallowed at inspection, unless it is not noticed AND you don’t reveal it. Not worth the risk. Use a small air cylinder.
It won’t pass inspection, unless your inspector doesn’t notice it. And with that packaging, I’m fairly certain they’ll ask. A number of head inspectors also read CD on a regular basis–if yours is one of those, you’re already not going to pass. Don’t try to pass with it on your robot.
[quote=Vikesrock;908225If the electromagnet just holds the part in place, then releases it, with no motion of latch parts then you should be OK.[/QUOTE]
I’d like to see a GDC ruling on this !
Holding is different than actuating.[/quote]
The GDC has ruled on holding already–see that second Q&A I linked. The part in question certainly seems to be an actuated device.
The GDC has been fairly clear.
Use a magnet to hold your claw to the bar? Fine.
Use a magnet to cause something to move? Not fine.
However, if someone still has a question, post it on the Q&A. None of our answers are official.
haha thanks for the tip, i’ve been looking into just an electromagnet with no latch instead, but we’ll probably go with a piston (more cost effective) ya you’re right about inspection too
Thanks again
For less than 1/2 the price of the gate latch you were looking at you can get an electromagnet rated for 160 lbs from McMaster-Carr part #5698K312.
All you would have to do is put an iron plate at the end of your kicker and make sure that the plate is pressed firmly against the electromagnet before the magnet is engaged.
However it is important to remember that the iron may become magnetized with unexpected results!
So do we have to buy the electromagnet or can we make our own.
I mean honestly, making an electromagnet is something i did in elementary school.
The only thing i am not sure about is does that violate the custom circuits rule?
Any help would be greatly appreciated.
So am I understanding this thread correctly, that if I have an aluminum pivot bar having a pin & a spring at one end, and a steel plate at other end, if my pin engages a bungee powered arm, locking it in place, and uses a spring around the pin that’s pushing to disengage it, then if my electromagnet’s grip on the steel plate on opposite end of aluminum pivot bar prevents spring from disengaging pin at other end of aluminum bar until the electromagnet is de-energized, allowing bar to now pivot from the spring’s force, and disengaging the pin — is this a violation?
The electromagnet merely releases its grip on a steel plate, allowing the previously overpowered weaker SPRING to now actuate the release of the pin. What element is the real actuator here ? Is it the electromagnet, or is it the spring?
Is it that an electromagnet MOVING an element is forbidden, but RELEASING ITS GRIP on an element is allowed?
-Dick Ledford
Yes. If the electromagnet is causing the motion, then it is considered a solenoid actuator and illegal (<R53>). If anything else is causing the motion, and the electromagnet is acting as a latch, then the electromagnet is considered an electromagnet and legal.
As far as buying/making your own, you’d probably want to ask that in Q&A. It would probably wind up being answered as “both”, but you never quite know.
So when you say “causing the motion”, this would mean initiating a force on an element applied so as to move it over a distance – i.e. doing work on an element. But a static steel plate stuck to an electromagnet is not in motion, despite the force being applied to hold it in its static position, so, de-energizing the electromagnet merely allows the pin release spring to now do the work of disengaging the pin, and allowing the release of the swing arm.
This seems fairly clear. Just no pushing or pulling MOVEMENT of elements by forces developed within an electromagnetic device are allowed. Only for HOLDING elements in a static position can an electromagnetic device’s force be used.
-Dick Ledford
Yes.
Note that the static position seems to be defined relative to the electromagnet–a team asked Q&A about whether a moving electromagnet (moved by a motor) would be legal, and got an affirmative answer.
The $ 64,000 question !! holding versus moving… need an authoritative definition of ‘solenoid’.
I’m guessing that the “holding” they refer to is the electromagnetic force created by the electromagnet. 272 (2008) physically moved the magnet and used the electromagnetic force to do the “holding”.