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Originally Posted by T134guy
As far as valve restrictions I tend to disagree with rickertsen's 3 way valve. This problem with it is that in a machine that uses lots of pnuematics(ie. 134 bot this past season which ran only two motors) it takes time and power to charge this system. Having a 3 way on a machine like that counters some of your previous arguements. (i could have misinterpretted you however)
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The valve WOULD NOT dump the accumulators, only depressurize downstream components. it does however create the below issue.
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Originally Posted by Andy Brockway
The example you cited is important for safety in industry, a critical need to dump all energy sources. While this is a common practice in industry it may not directly apply to FIRST. Many teams, including ours, use the air pressure in the disabled mode to position a part of the robot at the beginning or end of the match. This years example is all the hangers that withdrew their feet when the match ended.
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This is one thing i overlooked, but that could be prevented by using a 3 position double spring return valve with a blocked neutral state. Of couse judging by the dissaray of valves that have come in the kits the last few years, I think FIRST already has a hard enough time getting valves donated without going into anything fancy. But then agian the whole point of my crusade is to allow us to use one of those if we should so desire. I saw some weird combinations of valves to achieve multipostitioning etc that could have been achieved with a single part if we were not soo restricted.
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Originally Posted by ngreen
If you went to the pneumatics meeting at Atlanta we talked about some of these things. There is a company, can't think of, someone jog my memory that was looking into donating venturi style vaccum generators that weighed less than a 1/4 pounds, barely used any air, and had tremendous suction. If someone else knows the companies name and the device name clue everyone in. But this would solve everyones suction needs...
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The company was probably PIAB, whom my company is a distributor for and whose products i work with on a regular basis. These are exactly what i am referring to. In fact i can say that you are probably referring to either an Mini Chip M(xx)LP pump or a P3010 series pump. The Mini Chip M(xx)LP pumps weigh only a 16th of a pound and is 16.5mm high, 61mm long, and 30mm wide. I havn't weighed a P3010 pump (which is a little more efficient and has an integrated filter, but a stack of 2 would probably be needed in a robot that relied heavily on vacuum). The Mini Chip M(xx)LP pumps can generate a vacuum of up to 24.1-inHg with various max flow rates and air consumptions depending on what you fill the "xx" in with, from a 55psi supply. The P3010 pump can generate a vacuum of up to 27.0-inHg from a 45psi supply and has a max flow rate of 2.97scfm while consuming 1.00scfm of compressed air.
As an addendum to my previous comments, about allowing a greater selection of actuators, i was really referring to two things.
1.) I do not think we should be given a list that says "you can use these sylinders and no others", rather i think we should be given guidelines similar to the allowable parts flowchart. An example of the absurdity of the current regulations was the issue where peope were pressing out the clevis pin to get their cylinders to mount how they wnated them to. This could ahve bene avoided entirely if FIRST had just let us buy the proper cylinders in the first place. Bimba offers their classic line of cylinders with about a dozen different mounting options. Someone find me a reason why we shouldn't be able to use a cylinder that bolts down instead of using brackets, or why we shouldn't be able to use one with a hole instead of a clevis pin? There us a reason why the Bimba Classic line catalog takes up 152 pages.(The classic line is the series of cylinders provided in the FIRST kit.)
2.) I am happy about rotary actuators being allowed this past season, and i saw some creative uses for them. There is one other actuator i think should be allowed, that is the rodless cylinder. For those of you who have never seen a rodless cylinder, Here is a link to a pic of one as an example.
http://www.oylair.com/graphics/bimba...s_cylinder.jpg
I'm not saying that these things need to be incuded in the kit, only that they should be ALLOWED.
O one last thing. limiting selection ENCOURAGES BAD DESIGN PRACTICES. It teaches kids to use the wrong parts for the wrong purpose. The proper design practice is to use the right part for the job. I think that by allowing the proper parts, we would be raising the bar of FIRST stardards not lowering it. Robots would get more complex, not more like a lego set. We have only 6 weeks to build a robot. If we wasted less of that time on menial tasks such as hacking togther assemblies to use a standard cylinder as a rodless sylinder and focused more of our energies on important tasks, we could do alot more.