3 position cylinders

[implosionprez]

Rule <R74> says that

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]

Originally Posted by implosionprez

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]

Has anyone asked the GDC yet?

[wilsonmw04]

Originally Posted by implosionprez

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.

[Tristan Lall]

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.

[implosionprez]

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/

[Al Skierkiewicz]

Ty,
Can you provide a link to the actuator you are asking about?

[Chris Fultz]

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]

Originally Posted by Al Skierkiewicz

Ty,
Can you provide a link to the actuator you are asking about?

Originally Posted by Chris Fultz

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]

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]

Will do. Thanks for checking!

[Chris Fultz]

http://forums.usfirst.org/showthread.php?t=17069

Re: 2 Stage Bimba Cylinders

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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]

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]

Originally Posted by 1075guy

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>.

[craigcd]

3 port center port closed solenoid valves were illegal because they trapped pressure and would not allow the full pressure to be relieved. Why can't you add addition pressure relief surge valves to the line to the cylinder and accomplish the same thing? Might be a good question to ask the GDC..