Subject:
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Re: Old pneumatic pistons
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Newsgroups:
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lugnet.technic
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Date:
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Tue, 14 Nov 2000 10:54:51 GMT
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Viewed:
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634 times
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> As a side note: that direction valve doesn't function very good if you
> fill up your *pneumatic* system with water (hydraulic)... case and
> point, mine's bust due to an ill-formed stroke of genius at age 10...
I broke one direction valve while playing with the 8843 Fork Lift
Truck.
To further explain how the old-style pneumatics work:
The handpump creates air preassure when pressed down and suction when
pressed up. The spring on the pump is supposed to be pressing the
piston up but this works rather bad so one has to pull the piston by
hand.
The suction/preassure is led to the direction valve via one hoose. The
valve looks like a grey 2x4 brick with three connections to the side
of it. The middle connection is used to the pump and the two outer is
connected to the valves outer connections. Then the middle connector
of the valve is connected to the pneumatics connector.
Thus will there be one "system" with preassure and one with suction
all the way to the valve. The valve is identic to the once used today.
When the valve is flipped from one side to the other both the hoose
and the cylinder must be filled with either preassure or suction,
hence is the "reaction" of the old system poor. Another disadvantage
is when several valves is connected to one system using T-crosses,
like in the 8851 Excavator the valves cannot be crossed (one valve to
suction and one to pressure) because all the air will escape from the
system when this is happens.
One good thing is that only one hoose has to be led from the valve to
the cylinder, but I prefer the new-style pneumatics.
Hope this helps. If you want me to I can set up a page with schematics
of the two systems.
/Tobbe
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Message has 2 Replies:
 | | Re: Old pneumatic pistons
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| One thing I found with the old-style pneumatics, particularly the excavator, was that the down stroke was considerably easier, in fact, one had to pump very carefully if one only wanted a minor adjustment, otherwise the pressure of the entire (...) (24 years ago, 14-Nov-00, to lugnet.technic)
| | | Re: Old pneumatic pistons
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| One very useful application for the old-style pneumatics I've thought of is a single-cylinder, double-acting compressor. Using a new double-acting cylinder, connect each hose to the centre input of an old-style pneumatic brick, and connect the (...) (24 years ago, 15-Nov-00, to lugnet.technic)
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Message is in Reply To:
| | Re: Old pneumatic pistons
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| (...) As a side note: that direction valve doesn't function very good if you fill up your *pneumatic* system with water (hydraulic)... case and point, mine's bust due to an ill-formed stroke of genius at age 10... C. (24 years ago, 12-Nov-00, to lugnet.technic)
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