Mini-bot Hinges [Archive]

EricH

13-01-2011, 20:52

Are the mini-bots allowed to use hinges like door hinges, etc. to use as doors that close up around the pole?
Not if they aren't in <R92>, and I don't see "hinges" in there.

However, using aluminum, hardware, and maybe some surgical tubing or something, I'm sure you could rig up some form of hinge substitute.

baroneje

14-01-2011, 23:48

Are you allowed to mill them out of aluminum since the rules allow the use of sheet aluminum?

DonRotolo

14-01-2011, 23:48

I don't see why not.

StevenB

15-01-2011, 11:37

Not if they aren't in <R92>, and I don't see "hinges" in there.

As you mentioned, <R92> part S allows "Mechanical hardware (i.e. screws, bolts, etc). Pending clarification in the Q&A, I wouldn't completely rule out hinges as hardware. The hardware store calls them hardware, and you find them stocked pretty close to the screws and bolts.
See this thread (http://www.chiefdelphi.com/forums/showthread.php?threadid=89184) for more discussion.

EricH

15-01-2011, 12:49

As you mentioned, <R92> part S allows "Mechanical hardware (i.e. screws, bolts, etc). Pending clarification in the Q&A, I wouldn't completely rule out hinges as hardware. The hardware store calls them hardware, and you find them stocked pretty close to the screws and bolts.
See this thread (http://www.chiefdelphi.com/forums/showthread.php?threadid=89184) for more discussion.
But being close is not being equal. 5 is close to 4...

The specific examples in the rule tend to point towards fasteners, not springs and hinges (motion parts, we could call them).

J.Warsoff

17-01-2011, 21:21

I don't see why not.

yea i dont see why not either, Don. btw, i might want to use some kind of hinge in the prototype ive been working on, so hopefully i can get that going. i may need some help though

artdutra04

17-01-2011, 21:32

Are the mini-bots allowed to use hinges like door hinges, etc. to use as doors that close up around the pole?As long as it's made out of allowable parts, then yes.

Check out McMaster part #1635A24 (http://www.mcmaster.com/#1635a24). It's a 100% polycarbonate hinge, and thus should be legal.

BJT

18-01-2011, 22:02

Update#3 seems to rule out hinges on the minibot. you could make one, but purchasing a pre-made hinge, regardless of material, seems to be out. right?

awesomeguy1235

18-01-2011, 22:25

well, if it is listed in the parts you are allowed to use, then you can, but if it is not, then just forget it, my team thought of arms that used pulleys and surgical tubing to clamp it shut

PAR_WIG1350

18-01-2011, 22:48

Update #3 still doesn't rule out the polycarbonate hinge. I'd Q&A that one if I were you.

Chris is me

18-01-2011, 22:49

Update#3 seems to rule out hinges on the minibot. you could make one, but purchasing a pre-made hinge, regardless of material, seems to be out. right?

What of Team Update 3 makes purchasing premade parts illegal?

Jimmy the Kidd

18-01-2011, 23:02

Update#3 seems to rule out hinges on the minibot. you could make one, but purchasing a pre-made hinge, regardless of material, seems to be out. right?
A couple of the posters here and I seem to have the same opinion. You should be able to only MAKE hinges. Buying them is against the rules.

EricH

18-01-2011, 23:03

What of Team Update 3 makes purchasing premade parts illegal?
If they aren't Tetrix, and they aren't specifically listed (which the parts in question--hinges--are not), then you either have to make your own or go without. Team Update 3 removed all ambiguity on the "hardware" point by changing "hardware" to "fasteners".

Chris is me

18-01-2011, 23:14

If they aren't Tetrix, and they aren't specifically listed (which the parts in question--hinges--are not), then you either have to make your own or go without. Team Update 3 removed all ambiguity on the "hardware" point by changing "hardware" to "fasteners".

But the hinges are made exclusively of materials found on the list of allowed parts. Why is it suddenly required that you hand make them if they are literally just shaped versions of what is allowed?

EricH

18-01-2011, 23:27

But the hinges are made exclusively of materials found on the list of allowed parts. Why is it suddenly required that you hand make them if they are literally just shaped versions of what is allowed?
Ask the GDC.

I think many door hinges are steel, though. Steel isn't allowed... so you'd have to find aluminum ones. Or the polycarb ones listed earlier. Assuming, of course, that the GDC allows non-team-manufactured hardware that isn't otherwise legal.

Chris is me

18-01-2011, 23:29

Ask the GDC.

I think many door hinges are steel, though. Steel isn't allowed... so you'd have to find aluminum ones. Or the polycarb ones listed earlier. Assuming, of course, that the GDC allows non-team-manufactured hardware that isn't otherwise legal.

What I was trying to say is that Team Update 3 does not require that teams are the group that fabricated said materials - if the items are made from things exclusively from that list they are legal.

EricH

18-01-2011, 23:53

What I was trying to say is that Team Update 3 does not require that teams are the group that fabricated said materials - if the items are made from things exclusively from that list they are legal.
The GDC has not said that teams can go out and buy their X Minibot material pre-formed into final form. They have said that the team can machine said materials. If I were to go out and buy VEX metal (aluminum), I might have a hard time passing inspection as the rules stand. But I can go out and buy aluminum and machine it into VEX metal, and I'd get some funny looks but would probably pass inspection.

There's another way to look at this: Where, on the list of allowed materials, do you find COTS parts? Parts A-E (Tetrix/FTC), I, K-N, P, S, U, X, Y, AA, BB. All the other parts are going to require some modification. Rope, wire, tape, velcro, PVC, and loctite are all going to need to be removed from their containers or cut to length or otherwise worked with. Aluminum and polycarb will need to be cut and shaped and otherwise moved from raw material (the COTS form) to fabricated item.

I don't necessarily like it either, but that's the way the rules are currently written and interpreted. If that's not the way they should be written, then the GDC needs to change that--and I happen not to have access to ask that sort of question on Q&A.

Chris is me

19-01-2011, 00:01

If I were to go out and buy VEX metal (aluminum), I might have a hard time passing inspection as the rules stand. But I can go out and buy aluminum and machine it into VEX metal, and I'd get some funny looks but would probably pass inspection.

To put it frankly - I think you're making that restriction up. It's said nowhere in any Manual, you're just deriving it.

And for what it's worth (standard disclaimer that even posts by Dave Lavery on CD are no substitute for the Q&A here):

Isn't [Vex metal] still [aluminium sheet]?

If the Manual was worded differently I don't see why he'd make that post...

Bob Steele

19-01-2011, 00:03

What I was trying to say is that Team Update 3 does not require that teams are the group that fabricated said materials - if the items are made from things exclusively from that list they are legal.

I think you are swimming in dangerous water if you think that when they say polycarbonate that means you can use anything made of that...
i believe that the rule says polycarbonate and not polycarbonate parts...

This is one to ask Q and A

I will be very surprised if they say that a pre-made polycarbonate hinge is the same as "polycarbonate"

As an inspector unless I had a definite Q and A response that indicated that this was ok I would not allow that pre-made hinge.

And by the way... VEX metal isn't made of aluminum it is made of steel.
(You can get a very expensive set of VEX parts made in aluminum but the pieces you get in the kit and that 99% of all teams use are made of steel.

Dave's statement can be interpreted several ways... you decide how to do it..
Yes VEX metal is still steel...it was made of it...

But is steel the same as vex metal..???

artdutra04

19-01-2011, 00:18

Don't read into the rules what's not there.

"Polycarbonate" with no other strings attached is listed as a "permitted material" in rule R92F.

Where (exact rule #) are these imaginary restrictions on what constitutes legal polycarbonate and illegal polycarbonate coming from?

EricH

19-01-2011, 00:31

Art, <R92> simply states that "The following items are the only permitted materials for use on the MINIBOTS:"
[list]

It then lists a long line of various COTS-type items and what sure looks like raw materials. While it nowhere says "COTS" or "Fabricated item", there are strong conclusions that can be drawn from what the terminology says. For example, if the list had said "steel", would you think that screws, nuts, and bolts were legal? I know I wouldn't! But screws, nuts, and bolts are called out in another item on the list, so they are legal.

As it stands right now, both sides have the right answer, because clarification has not come. I'd much rather inspections not turn into lawyering to the effect of, "But it's made of X..." "But it's not on the list..." Somebody needs to ask Q&A. Something simple, like, "I can buy a COTS item that is entirely made of an allowed material from R92. This item is not listed elsewhere in R92. Is it legal?" would probably work quite well for getting a GDC response one way or the other.

Chris is me

19-01-2011, 00:54

artdutra04

19-01-2011, 00:55

For example, if the list had said "steel", would you think that screws, nuts, and bolts were legal?If made of steel, yes.

Reading between the lines are for philosophical or political discussions. FRC rules are black and white.

Aren_Hill

19-01-2011, 01:01

Now to find some 7068 aluminum bearings

EricH

19-01-2011, 01:06

So basically what you're saying is you're making up "strong conclusions" based on things you admit aren't said in the rules at all. Please for the sake of less-informed teams skimming over these threads do not post things you don't know to be true.Chris, do you know for sure that it is legal to use items that are COTS on the Minibot just because their material matches a legal material? If so, what rule? I'd be interested in knowing.

If made of steel, yes.

Reading between the lines are for philosophical or political discussions. FRC rules are black and white.Except that this one can be read in two ways, black and white. Like I said, I wouldn't see that "steel" included "steel screws, nuts, and bolts that I buy at a hardware store". I'd see "steel" and think, "steel plate, tube, bar that I can form stuff with". You're seeing "steel" and thinking "steel, plate, tube, bar, screw, nut, bolt, and other hardware". Two different points of view, one single word. Because it is quite possible to do that, I propose that we let this topic lie until somebody can ask the Q&A. I can't do that asking, BTW--no account and no team. Q&A is the only official source for making black or white into black and white.

Molten

19-01-2011, 01:16

Please for the sake of less-informed teams skimming over these threads do not post things you don't know to be true.

Since you brought up less-informed teams, wouldn't we be better off suggesting something isn't allowed that is rather then the opposite. I'd much rather get to a regional and find out I could use an extra motor then have to figure out how to do without one I was planning on using. Also, I think you should take Eric at his word. He isn't just a random guy that happens to post on here. He's read every manual for as long as I can remember and knows people who do the inspections. If he can interpret that way(even if your right and he is falsely interpreting it) so can inspectors.

To anyone that might stumble upon this thread: Don't use the hinges until it was asked in Q&A.

Chris is me

19-01-2011, 01:41

Chris, do you know for sure that it is legal to use items that are COTS on the Minibot just because their material matches a legal material? If so, what rule? I'd be interested in knowing.

It'd be the rule that says parts that match what the rules say can be used on the robot. That's... most of them.

"Polycarbonate" is a polymer. It is not a specific formation of that polymer in any particular sheet - all of which would be "COTS" anyway.

dtengineering

19-01-2011, 02:05

Is the COTS polycarbonate hinge legal?

Ask schrodinger's cat. Until the Q&A rules on it, the hinge is both legal and illegal.

According to the letter of the rule, as laid out, right now... I believe they are legal. At the very least, they are not specifically illegal.

But what you are seeing here is a number of FRC veterans reading that rule and putting it in to the context of previous GDC rulings over the past several years, and making a reasonable interpretation as to the intent of the rule.... and I believe they are correct. I believe the hinge, in the context of the rules and previous GDC decisions, is illegal.

So until someone opens the box, by asking the Q&A or undergoing tech inspection, the hinge, like the cat, is both alive and dead.

Jason

P.S. I don't want to imply that your robot is "legal" just because you've passed tech inspection. It is quite possible that you passed tech due to an oversight by your inspector that will require adjustment at some future point of time.

wexlerd1

19-01-2011, 09:03

You could use the tetrix servo-controlled hinges set up with two servos to increase power. You still may need latching mechanisms both to hold the arm(s) in place during robot movement and after minibot deployment.

IndySam

19-01-2011, 09:27

Many ways to make hinges under the rules from simple things like electrical tape or Velcro to machining hinges from aluminum bar.

artdutra04

27-01-2011, 11:38

For anyone looking to use hinges on their Minibot, this Q&A makes polycarbonate hinges legal:

http://forums.usfirst.org/showthread.php?t=16317

There are no restrictions on the size, shape or form of polycarbonate used in the construction of the MINIBOT. FTC rules do not apply to the FRC game.