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Subject: 
Re: Single acting pneumatics with spring return
Newsgroups: 
lugnet.technic, lugnet.robotics
Date: 
Thu, 7 Mar 2002 04:58:12 GMT
Viewed: 
1242 times
  
Rob Stehlik wrote:

Hello again,
I think I should have another go at this... I wanted to say "Check
this out, I found an interesting application for the old pneumatic
cylinders" What it came out sounding like was "Mr. Soh was wrong! Look
at me prove him wrong!"

How coincidental, but it too struck me that we needed to backtrack as
the thread was getting pretty muddled up. It seemed to me that we may
not be working on the same assumptions. So here's the re-play...

The post that you quoted http://news.lugnet.com/robotics/?n=16764
was in response to Jennifer Clark's suggestion to use two air tanks, one
on the high pressure hose and the other on the vacuum hose between the
pneumatic diode and the valve.

The tacit assumption here is that the pneumatics were being used in the
conventional manner, that is with pneumatic cylinders being controlled
by the valve to retract and to extend the piston. It is in this context
that it was said that the air tanks would not work with the old
pneumatics. (The experimental setup is shown at
http://www.geocities.com/cssoh1/primer/oldpneu.htm).

But perhaps, it would have been clearer if I had qualified that the air
tanks would not work with the old pneumatics *when connected in the
conventional manner* (hopefully this is easily understood).

... my window walker can climb happily away as long as the
tanks have a lower than atmospheric pressure in them. If I pump most
of the air out to start, the robot can climb about 6 steps before
needing a recharge. I suppose it would work without the air tanks, but
not as well:)

Now, the window walker is an exception. It is not using the old
pneumatics in the conventional manner (as defined above). Indeed, it is
using pneumatics in a most irregular manner. There are none of the old
pneumatic cylinders to speak of. Therefore there is no need for
alternate compression and suction. The pneumatic valve is simply being
used to switch the *vacuum* from one pair of suction cups to the other
pair. So I reckon this critter can be left to continue carrying the
tanks on its back ;-)

--
C S Soh

CSSoh's Lego Pneumatics
http://www.geocities.com/cssoh1
... where air is power!



Message is in Reply To:
  Single acting pneumatics with spring return
 
Hello again, I think I should have another go at this... I wanted to say "Check this out, I found an interesting application for the old pneumatic cylinders" What it came out sounding like was "Mr. Soh was wrong! Look at me prove him wrong!" Sorry (...) (22 years ago, 6-Mar-02, to lugnet.technic, lugnet.robotics)

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