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-   -   3 position cylinders (http://www.chiefdelphi.com/forums/showthread.php?t=91666)

implosionprez 12-02-2011 21:11

3 position cylinders
 
Rule <R74> says that
Quote:

Each commanded motion of a pneumatic cylinder or rotary actuator must be accomplished via the flow of compressed air through only one approved pneumatic valve.
Does this illlegalize 3 position cylinders, or are 3 position cylinders legal because they are technically 2 cylinders put together?

Mike Betts 12-02-2011 21:22

Re: 3 position cylinders
 
Quote:

Originally Posted by implosionprez (Post 1021682)
Rule <R74> says that Does this illlegalize 3 position cylinders, or are 3 position cylinders legal because they are technically 2 cylinders put together?

You should ask the GDC officially.

implosionprez 12-02-2011 21:37

Re: 3 position cylinders
 
Has anyone asked the GDC yet?

wilsonmw04 12-02-2011 21:40

Re: 3 position cylinders
 
Quote:

Originally Posted by implosionprez (Post 1021708)
Has anyone asked the GDC yet?

not from my quick hour of looking, but don't limit yourself to the "Pneumatics" section. Pneumatics can be found all over the "the Robot" section of the
Q & A.

Al Skierkiewicz 12-02-2011 21:44

Re: 3 position cylinders
 
Ty,
Can you provide a link to the actuator you are asking about?

Tristan Lall 12-02-2011 21:48

Re: 3 position cylinders
 
It seems to me that one valve means one valve.

Here's how you plumb a 2-port 3-position cylinder with a single 5/3 valve.

This 3-port arrangement probably wouldn't work for you, unless you found an appropriate valve.

Chris Fultz 12-02-2011 21:53

Re: 3 position cylinders
 
Here is a Bimba 3 position. We may use one. I have posted in the Q+A.

http://bimba.com/pdf/catalogs/FL_Ori...ne.pdf#page=67

Here is a pdf explaining how they work.

http://www.bimba.com/pdf/catalogs/TRD_3P_Series.pdf

I don't know what the GDC will say, but I would say these are safer than connecting multiple cylinders together at the clevis or foot end, because these are built as a joined pair.

implosionprez 12-02-2011 21:56

Re: 3 position cylinders
 
Here is a link to the 3 position cylinders. My only worry is that it's a violation of <R74>. http://www.bimba.com/Products/Origin...tionCylinders/

Chris Fultz 12-02-2011 22:01

Re: 3 position cylinders
 
Quote:

<R74> Each commanded motion of a pneumatic cylinder or rotary actuator must be accomplished via the flow of compressed air through only one approved pneumatic valve. Plumbing the outputs from multiple valves together into the same input on a pneumatic cylinder is prohibited.
I posted the question.

My interpretation is that the three position cylinders are legal, as long as you only have one solenoid connected to each input. The rule does not say one solenoid connected to each cylinder.

I will post the response from the GDC when I see it.

implosionprez 12-02-2011 22:02

Re: 3 position cylinders
 
Quote:

Originally Posted by Al Skierkiewicz (Post 1021716)
Ty,
Can you provide a link to the actuator you are asking about?

Quote:

Originally Posted by Chris Fultz (Post 1021725)
Here is a Bimba 3 position. We may use one. I have posted in the Q+A.

http://bimba.com/pdf/catalogs/FL_Ori...ne.pdf#page=67

I can't post a link (immediately) because a moderator has to approve it, but These cylinders from Bimba are the ones I'm talking about. I worry about <R74>, because it's technically one cylinder, with multiple solenoids, but it's also technically two cylinders together.

Al Skierkiewicz 12-02-2011 22:49

Re: 3 position cylinders
 
Ty,
I do not see that the use of this cylinder and multiple solenoids would violate R74. R74 specifically is written to prevent more than one valve to feed the same input on a cylinder in an attempt to make the cylinder react faster. I must abide by by the ruling of the GDC and I have been wrong before. Please standby until they respond.

implosionprez 12-02-2011 22:54

Re: 3 position cylinders
 
Will do. Thanks for checking!

Chris Fultz 16-02-2011 13:47

Re: 3 position cylinders
 
http://forums.usfirst.org/showthread.php?t=17069

Re: 2 Stage Bimba Cylinders

--------------------------------------------------------------------------------

As long as <R74> is followed and "each commanded motion of a pneumatic cylinder is accomplished via the flow of compressed air through only one approved pneumatic valve" and these cylinders meet the requirements of <R66>, the cylinders are allowed.

Racer26 16-02-2011 14:27

Re: 3 position cylinders
 
Interesting note: Does <R74> as written outlaw the design 1075 used in 2004 and 2007 for stopping a pneumatic cylinder mid-stroke?

By passing the exhaust ports of a valve into the P port of another valve, with a looped hose connecting A and B, plugging EA. This seems like TWO valves controlling the flow through that ONE cylinder, though only ONE valve is DIRECTLY connected to the cylinder.

bstrong1218 16-02-2011 15:02

Re: 3 position cylinders
 
Quote:

Originally Posted by 1075guy (Post 1024428)
Interesting note: Does <R74> as written outlaw the design 1075 used in 2004 and 2007 for stopping a pneumatic cylinder mid-stroke?

By passing the exhaust ports of a valve into the P port of another valve, with a looped hose connecting A and B, plugging EA. This seems like TWO valves controlling the flow through that ONE cylinder, though only ONE valve is DIRECTLY connected to the cylinder.

No clue if it's just a negative externality of the pneumatics rules this year, but position control with multiple solenoids or even a single 3 position, normally closed solenoid seems to have been outlawed.

Check the official Q&A... our team asked about what you're describing as did a few others and the answers point to a violation of <R74>.


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