Subject:
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Re: pneumatic cylinder: why not hydraulic ??
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Newsgroups:
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lugnet.technic
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Date:
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Fri, 9 Apr 2004 05:14:17 GMT
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Viewed:
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2883 times
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In lugnet.technic, Mark Bellis wrote:
> In lugnet.technic, Ross Crawford wrote:
> > In lugnet.technic, Kevin L. Clague wrote:
> > > In lugnet.technic, Chris Masclet wrote:
> > > > Hi everybody,
> > > >
> > > > I' ve read a long time ago something like this: LEGO pneumatic cylinder cannot
> > > > be use as hydraulic cylinder.
> > > >
> > > > Is anybody can explain me why ?? May be we can' t use water with cylinder (may
> > > > be cause of corrosion) but what about silicone oil ?? or something like that....
> > >
> > >
> > > The simplest reason is that when the switch is flipped to one side, the other
> > > port is released to the atmosphere.
> > >
> > > This means that your hydraulic fluid would spill all over the floor.
> >
> > Well one solution to that problem is to position all the switches above a
> > "hydraulic fluid catchment area", however I still think it would be prone to
> > spillage ;)
> >
> > ROSCO
>
> One key thing about hydraulics has always been "avoid leaks". To switch the
> fluid, just invent something I've wished for for years - the reverser switch.
> This switch has four ports, used in opposing pairs. Clockwise in a circle they
> would be A, C, B, D. In the middle position all ports are blocked. Pushed one
> way and A-C and B-D are connected. Push the other way and A-D and B-C are
> connected. The equivalent is to use four switches, with ports A to D being the
> middle ports of each switch. Connect the outer ports of the switches so that
> you get a crossover of the pipes without any leakage to the atmosphere in any
> position, whilst moving all four switch levers together. With ports on a switch
> being L, M and R, connect 1L to 3L, 1R to 4R, 2L to 4L and 2R to 3R. Connect
> the inputs to 1M and 2M and a cylinder to 3M and 4M.
Mark,
I thought this one through, and I get it. I can see how it works. The
solution works equally well as my solution. I don't think mine is any more or
less complicated, just different. Less hoses, more T's and other technic parts
than yours.
The wonderful thing is there are two different solutions, and each have their
strengths.
I've been working on an advanced hexapod that needs 12 reversors. The
geometry of my reversors present some problems because they are so tall, and
they have to be out of phase. I'm going to try your reversors and see if they
fit better in the geometries I already have. I think your geometry will work
better.
I'll keep you informed.
Kevin
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Message has 1 Reply:
 | | Re: pneumatic cylinder: why not hydraulic ??
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| (...) If you're short of space you can always double the reverser back on itself if you're using the new switches from 8455, in a similar way to your picture. That's why I like the new switches. A 2x2 switch module is probably easier to accomodate (...) (21 years ago, 9-Apr-04, to lugnet.technic)
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Message is in Reply To:
| | Re: pneumatic cylinder: why not hydraulic ??
|
| (...) One key thing about hydraulics has always been "avoid leaks". To switch the fluid, just invent something I've wished for for years - the reverser switch. This switch has four ports, used in opposing pairs. Clockwise in a circle they would be (...) (21 years ago, 7-Apr-04, to lugnet.technic)
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